Electric-hexadecapole (24-pole) Coulomb integrals
NASA Astrophysics Data System (ADS)
Chidichimo, Marita C.; Stastna, Marek
1996-03-01
We obtain the quantal zero-energy-loss limit of the radial integrals arising in the nonrelativistic atomic excitation of electric-hexadecapole transitions. We compare these results to the classical limit and the WKB approximation. We show the different behavior of the Coulomb integrals in the WKB approximation in the cases of repulsive and attractive potentials as functions of the Sommerfeld number η.
Convergence of Feynman integrals in Coulomb gauge QCD
Andraši, A.; Taylor, J.C.
2014-12-15
At 2-loop order, Feynman integrals in the Coulomb gauge are divergent over the internal energy variables. Nevertheless, it is known how to calculate the effective action, provided that the external gluon fields are all transverse. We show that, for the two-gluon Greens function as an example, the method can be extended to include longitudinal external fields. The longitudinal Greens functions appear in the BRST identities. As an intermediate step, we use a flow gauge, which interpolates between the Feynman and Coulomb gauges.
On Dirac-Coulomb problem in (2+1) dimensional space-time and path integral quantization
Haouat, S.; Chetouani, L.
2012-06-15
The problem of Dirac particle interacting with Coulomb potential in (2+1) dimensions is formulated in the framework of super-symmetric path integrals where the spin degrees of freedom are described by odd Grassmannian variables. The relative propagator is expressed through Cartesian coordinates in a Hamiltonian form by the use of an adequate transformation. The passage to the polar coordinates permitted us to calculate the fixed energy Green's function and to extract bound states and associating wave functions.
Przybytek, Michal; Helgaker, Trygve
2013-08-07
We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (γ(H) = 2) and eight (γ(1st) = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (αmin (G)=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d(4) with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step-namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems
NASA Astrophysics Data System (ADS)
Przybytek, Michal; Helgaker, Trygve
2013-08-01
We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (γH = 2) and eight (γ1st = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (α _min^G=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d4 with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step—namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems
Low rank factorization of the Coulomb integrals for periodic coupled cluster theory
NASA Astrophysics Data System (ADS)
Hummel, Felix; Tsatsoulis, Theodoros; Grüneis, Andreas
2017-03-01
We study a tensor hypercontraction decomposition of the Coulomb integrals of periodic systems where the integrals are factorized into a contraction of six matrices of which only two are distinct. We find that the Coulomb integrals can be well approximated in this form already with small matrices compared to the number of real space grid points. The cost of computing the matrices scales as O (N4) using a regularized form of the alternating least squares algorithm. The studied factorization of the Coulomb integrals can be exploited to reduce the scaling of the computational cost of expensive tensor contractions appearing in the amplitude equations of coupled cluster methods with respect to system size. We apply the developed methodologies to calculate the adsorption energy of a single water molecule on a hexagonal boron nitride monolayer in a plane wave basis set and periodic boundary conditions.
Coulomb Stress Distribution Along the Fairweather and Queen Charlotte Transform Fault System
NASA Astrophysics Data System (ADS)
Bufe, C. G.
2004-12-01
Tectonic loading and Coulomb stress transfer are modeled along the right-lateral Fairweather and Queen Charlotte transform fault system using a three-dimensional boundary element program. The loading model includes slip below 12 km along the transform as well as motion of the Pacific plate and is consistent with most available GPS displacement rate data. Coulomb stress transfer from adjacent fault segments is shown to be a weak contributing factor to the failure of the southeastern (Sitka) segment of the Fairweather fault (M 7.6, 1972), advancing the clock by only about 8 months. Failure resulted from a combination of loading from below (99 percent) by slip of nearly 5 cm/yr since before1900, and of stress transfer (1 percent) from major earthquakes on adjoining segments of the Queen Charlotte fault to the southeast (M 8.1 in 1949) and the Fairweather fault to the northwest (M 7.8 on Lituya segment in 1958). Combined Coulomb stress increases exceeded 4 MPa at a depth of 8 km prior to the Sitka earthquake. Coulomb stress transferred from the nearby M 9.2 Alaska earthquake of 1964 also may have advanced the clock for the 1972 event, but only by a month or two. Minimum recurrence times, based on average co-seismic displacements estimated from seismic moments and fault dimensions, range from about 80 years for the 1958 and 1972 events to 160 years for the 1949 earthquake. This implies stresses of 5 to 10 MPa at 8 km depth at failure, assuming total stress drops. Continued tectonic loading over the last half century and stress transfer from the M 7.6 Sitka event has resulted in re-stressing the adjacent segments by about 3 MPa at 8 km depth, as evidenced by the occurrence of a M 6.8 earthquake on the northwestern part of the Queen Charlotte fault on June 28, 2004, the largest since 1949. The segment of the Queen Charlotte fault immediately southeast of the 1949 rupture has accumulated about 6 MPa at 8 km through loading since 1900 and stress transfer in 1949. A
Closed-form expressions for the Dirac-Coulomb radial rt integrals
NASA Astrophysics Data System (ADS)
Bessis, N.; Bessis, G.; Roux, D.
1985-10-01
A novel procedure is devised in order to obtain closed-form expressions of the Dirac-Coulomb radial rt integrals in terms of the Dirac energy ɛ=\\{1+Z2α2/[v+(k2-Z2 α2)1/2]2\\}-1/2, where v=n-||k||, and of the Dirac quantum number k=(-1)j+l+1/2(j+(1/2)). In this procedure, well adapted for symbolic computation, the fundamental array of the rt radial integrals is obtained from the rt-1 array.
Guseinov, Israfil; Mamedov, Bahtiyar; Rzaeva, Afet
2002-04-01
The recurrence relations are established for the basic one-center Coulomb integrals over Slater-type orbitals (STOs). These formulae and the recurrence relations for basic overlap integrals are utilized for the calculation of multicenter electron-repulsion integrals. The calculations of multicenter electron-repulsion integrals are performed by the use of translation formulae for STOs obtained from the Lambda and Coulomb Sturmian exponential-type functions (ETFs). It is shown that these integrals show a faster convergence rate in the case of Coulomb Sturmian ETFs. The accuracy of the results is quite high for the quantum numbers of STOs and for the arbitrary values of internuclear distances and screening constants of atomic orbitals.
Off-shell Jost solutions for Coulomb and Coulomb-like interactions in all partial waves
Laha, U.; Bhoi, J.
2013-01-15
By exploiting the theory of ordinary differential equations, with judicious use of boundary conditions, interacting Green's functions and their integral transforms together with certain properties of higher transcendental functions, useful analytical expressions for the off-shell Jost solutions for motion in Coulomb and Coulomb-nuclear potentials are derived in maximal reduced form through different approaches to the problem in the representation space. The exact analytical expressions for the off-shell Jost solutions for Coulomb and Coulomb-like potentials are believed to be useful for the description of the charged particle scattering/reaction processes.
NASA Astrophysics Data System (ADS)
Hestand, Nicholas J.; Spano, Frank C.
2015-12-01
The spectroscopic differences between J and H-aggregates are traditionally attributed to the spatial dependence of the Coulombic coupling, as originally proposed by Kasha. However, in tightly packed molecular aggregates wave functions on neighboring molecules overlap, leading to an additional charge transfer (CT) mediated exciton coupling with a vastly different spatial dependence. The latter is governed by the nodal patterns of the molecular LUMOs and HOMOs from which the electron (te) and hole (th) transfer integrals derive. The sign of the CT-mediated coupling depends on the sign of the product teth and is therefore highly sensitive to small (sub-Angstrom) transverse displacements or slips. Given that Coulombic and CT-mediated couplings exist simultaneously in tightly packed molecular systems, the interference between the two must be considered when defining J and H-aggregates. Generally, such π-stacked aggregates do not abide by the traditional classification scheme of Kasha: for example, even when the Coulomb coupling is strong the presence of a similarly strong but destructively interfering CT-mediated coupling results in "null-aggregates" which spectroscopically resemble uncoupled molecules. Based on a Frenkel/CT Holstein Hamiltonian that takes into account both sources of electronic coupling as well as intramolecular vibrations, vibronic spectral signatures are developed for integrated Frenkel/CT systems in both the perturbative and resonance regimes. In the perturbative regime, the sign of the lowest exciton band curvature, which rigorously defines J and H-aggregation, is directly tracked by the ratio of the first two vibronic peak intensities. Even in the resonance regime, the vibronic ratio remains a useful tool to evaluate the J or H nature of the system. The theory developed is applied to the reversible H to J-aggregate transformations recently observed in several perylene bisimide systems.
Hestand, Nicholas J.; Spano, Frank C.
2015-12-28
The spectroscopic differences between J and H-aggregates are traditionally attributed to the spatial dependence of the Coulombic coupling, as originally proposed by Kasha. However, in tightly packed molecular aggregates wave functions on neighboring molecules overlap, leading to an additional charge transfer (CT) mediated exciton coupling with a vastly different spatial dependence. The latter is governed by the nodal patterns of the molecular LUMOs and HOMOs from which the electron (t{sub e}) and hole (t{sub h}) transfer integrals derive. The sign of the CT-mediated coupling depends on the sign of the product t{sub e}t{sub h} and is therefore highly sensitive to small (sub-Angstrom) transverse displacements or slips. Given that Coulombic and CT-mediated couplings exist simultaneously in tightly packed molecular systems, the interference between the two must be considered when defining J and H-aggregates. Generally, such π-stacked aggregates do not abide by the traditional classification scheme of Kasha: for example, even when the Coulomb coupling is strong the presence of a similarly strong but destructively interfering CT-mediated coupling results in “null-aggregates” which spectroscopically resemble uncoupled molecules. Based on a Frenkel/CT Holstein Hamiltonian that takes into account both sources of electronic coupling as well as intramolecular vibrations, vibronic spectral signatures are developed for integrated Frenkel/CT systems in both the perturbative and resonance regimes. In the perturbative regime, the sign of the lowest exciton band curvature, which rigorously defines J and H-aggregation, is directly tracked by the ratio of the first two vibronic peak intensities. Even in the resonance regime, the vibronic ratio remains a useful tool to evaluate the J or H nature of the system. The theory developed is applied to the reversible H to J-aggregate transformations recently observed in several perylene bisimide systems.
Higher-order time integration of Coulomb collisions in a plasma using Langevin equations
Dimits, A. M.; Cohen, B. I.; Caflisch, R. E.; ...
2013-02-08
The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional Euler-Maruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the two fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(Δt) vs. O(Δt1/2)] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if andmore » only if the “area-integral” terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the Euler-Maruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. Lastly, this method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.« less
Higher-order time integration of Coulomb collisions in a plasma using Langevin equations
Dimits, A. M.; Cohen, B. I.; Caflisch, R. E.; Rosin, M. S.; Ricketson, L. F.
2013-02-08
The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional Euler-Maruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the two fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(Δt) vs. O(Δt^{1/2})] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if and only if the “area-integral” terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the Euler-Maruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. Lastly, this method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.
Transformational Leadership, Integrity, and Power
ERIC Educational Resources Information Center
Harrison, Laura M.
2011-01-01
Transformational leadership enjoys widespread appeal among student affairs professionals. National Association of Student Personnel Administrators (NASPA) and American College Personnel Association (ACPA) conferences frequently feature speakers who promote transformational leadership's two primary tenets: (1) change is the central purpose of…
NASA Technical Reports Server (NTRS)
Straton, Jack C.
1989-01-01
The four-dimensional Fourier-Feynman transformations previously used in analytically reducing the general class of integrals containing multicenter products of 1s hydrogenic orbitals, Coulomb or Yukawa potentials, and plane waves, are replaced by the one-dimensional Gaussian transformation. This reduces the previously required double-diagonalization of the quadratic form of the multicenter integrals to only one diagonalization, yielding a simpler reduced form of the integral. The present work also extends the result to include all s states and pairs of states with l not equal to zero summed over the m quantum number.
NASA Astrophysics Data System (ADS)
Hollman, David S.; Schaefer, Henry F.; Valeev, Edward F.
2015-04-01
A new estimator for three-center two-particle Coulomb integrals is presented. Our estimator is exact for some classes of integrals and is much more efficient than the standard Schwartz counterpart due to the proper account of distance decay. Although it is not a rigorous upper bound, the maximum degree of underestimation can be controlled by two adjustable parameters. We also give numerical evidence of the excellent tightness of the estimator. The use of the estimator will lead to increased efficiency in reduced-scaling one- and many-body electronic structure theories.
Science education, integral inquiry, transformation and possibility
NASA Astrophysics Data System (ADS)
Stack, Sue
2013-09-01
This paper is written in response to Nancy Davis's article Integral Methodological Pluralism in Science Education Research: Valuing Multiple Perspectives. I use Integral Theory as a framing for this response to explore how it might offer different perspectives and ways of inquiring into Nancy's paper. This process highlights the notion of integral inquiry as a potential for personal transformation. I give an autobiographical account of my own experience in utilising Integral Theory as part of my PhD and its impact on my own becoming. For another perspective I interview Nancy to draw out deeper shared meanings.
NASA Astrophysics Data System (ADS)
Skarbek, Rob; Ikari, Matt; Hüpers, Andre; Rempel, Alan; Wilson, Dean; Kitajima, Hiroko
2014-05-01
In accretionary wedges, the mechanical and hydrologic properties along splay faults and the plate boundary fault at the base of the wedge are intimately related to properties within the wedge itself, as well as to sedimentation and/or mass wasting at the wedge surface, and accretionary flux at the wedge toe; Coulomb wedge theories tie these processes together and have been successful in their application to convergent margins. Most such theories assume for the sake of simplicity that mechanical parameters (e.g. bulk density, compressibility, frictional strength) and pore pressure are constant throughout the overlying wedge. However, the values of these parameters must necessarily change with depth and distance from the trench. Here, we derive a model for a fully general Coulomb wedge, parameterized using data specific to the Kumano transect at Nankai, to better understand the location of the basal plate interface and the properties of material composing an actively accretionary prism. We use shear strength data collected for incoming sediments at Integrated Ocean Drilling Program Site C0011 of the NanTroSEIZE project to parameterize the wedge's coefficient of friction. Preliminary results of models where the friction coefficient of the wedge decreases with depth, with other parameters constant and zero cohesion, indicate that including depth dependent frictional strength in the wedge decreases the taper angle of the wedge, with the effect becoming more pronounced with distance from the trench. This model will be further refined by including seismically and numerically determined spatial variations in fluid pressure within the wedge, as well as detailed locations of the upper and basal wedge surfaces along the Kumano transect determined from 3-D seismic data.
ERIC Educational Resources Information Center
Fay, Temple H.
2012-01-01
Viscous damping is commonly discussed in beginning differential equations and physics texts but dry friction or Coulomb friction is not despite dry friction being encountered in many physical applications. One reason for avoiding this topic is that the equations involve a jump discontinuity in the damping term. In this article, we adopt an energy…
Guseinov, Israfil I; Sahin, Ercan
2011-04-01
By the use of ellipsoidal coordinates, the two-center Coulomb and hybrid integrals over complete orthonormal sets of Ψα-ETO exponential type orbitals arising in ab initio calculations of molecules are evaluated, where α = 1,0, -1, -2, ...,. These integrals are expressed through the auxiliary functions Q(ns)(q) and G(-ns)(q). The comparison is made with some values of integrals for Slater type orbitals the computation results of which are in good agreement with those obtained in the literature. The relationships obtained are valid for the arbitrary quantum numbers, screening constants and location of orbitals. Closed form expressions for two-center Coulomb and hybrid integrals for 1s and 2s orbitals with α = 1 are also presented. As an example of application, the Hartree-Fock-Roothaan calculations for the ground state of H(2) molecule are carried out with α = 1 and α = 0.
NASA Astrophysics Data System (ADS)
Bardhan, Jaydeep P.
2008-10-01
The importance of molecular electrostatic interactions in aqueous solution has motivated extensive research into physical models and numerical methods for their estimation. The computational costs associated with simulations that include many explicit water molecules have driven the development of implicit-solvent models, with generalized-Born (GB) models among the most popular of these. In this paper, we analyze a boundary-integral equation interpretation for the Coulomb-field approximation (CFA), which plays a central role in most GB models. This interpretation offers new insights into the nature of the CFA, which traditionally has been assessed using only a single point charge in the solute. The boundary-integral interpretation of the CFA allows the use of multiple point charges, or even continuous charge distributions, leading naturally to methods that eliminate the interpolation inaccuracies associated with the Still equation. This approach, which we call boundary-integral-based electrostatic estimation by the CFA (BIBEE/CFA), is most accurate when the molecular charge distribution generates a smooth normal displacement field at the solute-solvent boundary, and CFA-based GB methods perform similarly. Conversely, both methods are least accurate for charge distributions that give rise to rapidly varying or highly localized normal displacement fields. Supporting this analysis are comparisons of the reaction-potential matrices calculated using GB methods and boundary-element-method (BEM) simulations. An approximation similar to BIBEE/CFA exhibits complementary behavior, with superior accuracy for charge distributions that generate rapidly varying normal fields and poorer accuracy for distributions that produce smooth fields. This approximation, BIBEE by preconditioning (BIBEE/P), essentially generates initial guesses for preconditioned Krylov-subspace iterative BEMs. Thus, iterative refinement of the BIBEE/P results recovers the BEM solution; excellent agreement
Data integration using color space transforms
Feuquay, Jay W.
1987-01-01
The demand for increased spatial resolution without sacrificing spectral discrimination can be fulfilled by integration of data from different sensor systems and satellite programs. Data of high spatial resolution are frequently available in panchromatic (black-and-white) form rather than multispectral. Techniques gave been developed to combine the higher resolution panchromatic data with a multispectral data set of lower spatial resolution. The standard method of integration modulates the intensity of the mutispectral with the panchromatic data. A less subjective approach uses an algorithm that describes color in terms of intensity (I), hue (H), and saturation (S). Combinations of high resolution panchromatic data (SPOT panchromatic) and lower resolution multispectral data [Landsat thematic mapper (TM), SPOT XS] have been developed. The SPOT data were acquired on April 3, 1986, and the Landsat TM data were acquired on April 5, 1986. The data sets were registered to each other and the multi-spectral data sets were contrast enhanced. The enhanced multispectral data sets were then transformed from red/green/blue (RGB) color space into IHS space. In each case (TM/SPOT panchromatic and SPOT XS/SPOT panchromatic), the SPOT panchromatic data were remapped on a cumulative histogram percentage basis to match the multispectral "I" data. These remapped SPOT panchromatic data were substituted for the original multispectral "I" and the hybrid IHS data transformed back into RGB space for display. While this technique is experimental and still being refined, the results, to date, indicate that the IHS method will be valuable for generating improved images that effectively present both high resolution spatial digital data and multispectral data.
Radon transforms and Gegenbauer-Chebyshev integrals, II; examples
NASA Astrophysics Data System (ADS)
Rubin, Boris
2016-08-01
We transfer the results of Part I related to the modified support theorem and the kernel description of the hyperplane Radon transform to totally geodesic transforms on the sphere and the hyperbolic space, the spherical slice transform, and the spherical mean transform for spheres through the origin. The assumptions for functions are formulated in integral terms and close to minimal.
Allied health: integral to transforming health.
Lizarondo, Lucylynn; Turnbull, Catherine; Kroon, Tracey; Grimmer, Karen; Bell, Alison; Kumar, Saravana; McEvoy, Maureen; Milanese, Steve; Russell, Mary; Sheppard, Lorraine; Walters, Julie; Wiles, Louise
2016-04-01
Objective South Australia is taking an innovative step in transforming the way its healthcare is organised and delivered to better manage current and future demands on the health system. In an environment of transforming health services, there are clear opportunities for allied health to assist in determining solutions to various healthcare challenges. A recent opinion piece proposed 10 clinician-driven strategies to assist in maximising value and sustainability of healthcare in Australia. The present study aimed to seek the perspectives of allied health clinicians, educators, researchers, policy makers and managers on these strategies and their relevance to allied health. Methods A survey of allied health practitioners was undertaken to capture their perspectives on the 10 clinician-driven strategies for maximising value and sustainability of healthcare in Australia. Survey findings were then layered with evidence from the literature. Results Highly relevant across allied health are the strategies of discontinuation of low value practices, targeting clinical interventions to those getting greatest benefit, active involvement of patients in shared decision making and self-management and advocating for integrated systems of care. Conclusions Allied health professionals have been involved in the South Australian healthcare system for a prolonged period, but their services are poorly recognised, often overlooked and not greatly supported in existing traditional practices. The results of the present study highlight ways in which healthcare services can implement strategies not only to improve the quality of patient outcomes, but also to offer innovative solutions for future, sustainable healthcare. The findings call for concerted efforts to increase the utilisation of allied health services to ensure the 'maximum value for spend' of the increasingly scarce health dollar. What is known about the topic? In medicine, clinician-driven strategies have been proposed to
Soft-core potentials in thermodynamic integration: comparing one- and two-step transformations.
Steinbrecher, Thomas; Joung, InSuk; Case, David A
2011-11-30
Molecular dynamics-based free energy calculations allow the determination of a variety of thermodynamic quantities from computer simulations of small molecules. Thermodynamic integration (TI) calculations can suffer from instabilities during the creation or annihilation of particles. This "singularity" problem can be addressed with "soft-core" potential functions which keep pairwise interaction energies finite for all configurations and provide smooth free energy curves. "One-step" transformations, in which electrostatic and van der Waals forces are simultaneously modified, can be simpler and less expensive than "two-step" transformations in which these properties are changed in separate calculations. Here, we study solvation free energies for molecules of different hydrophobicity using both models. We provide recommended values for the two parameters α(LJ) and β(C) controlling the behavior of the soft-core Lennard-Jones and Coulomb potentials and compare one- and two-step transformations with regard to their suitability for numerical integration. For many types of transformations, the one-step procedure offers a convenient and accurate approach to free energy estimates.
Fast Fourier transform based direct integration algorithm for the linear canonical transform
NASA Astrophysics Data System (ADS)
Wang, Dayong; Liu, Changgeng; Wang, Yunxin; Zhao, Jie
2011-03-01
The linear canonical transform(LCT) is a parameterized linear integral transform, which is the general case of many well-known transforms such as the Fourier transform(FT), the fractional Fourier transform(FRT) and the Fresnel transform(FST). These integral transforms are of great importance in wave propagation problems because they are the solutions of the wave equation under a variety of circumstances. In optics, the LCT can be used to model paraxial free space propagation and other quadratic phase systems such as lens and graded-index media. A number of algorithms have been presented to fast compute the LCT. When they are used to compute the LCT, the sampling period in the transform domain is dependent on that in the signal domain. This drawback limits their applicability in some cases such as color digital holography. In this paper, a Fast-Fourier-Transform-based Direct Integration algorithm(FFT-DI) for the LCT is presented. The FFT-DI is a fast computational method of the Direct Integration(DI) for the LCT. It removes the dependency of the sampling period in the transform domain on that in the signal domain. Simulations and experimental results are presented to validate this idea.
Fast Fourier transform based direct integration algorithm for the linear canonical transform
NASA Astrophysics Data System (ADS)
Wang, Dayong; Liu, Changgeng; Wang, Yunxin; Zhao, Jie
2010-07-01
The linear canonical transform(LCT) is a parameterized linear integral transform, which is the general case of many well-known transforms such as the Fourier transform(FT), the fractional Fourier transform(FRT) and the Fresnel transform(FST). These integral transforms are of great importance in wave propagation problems because they are the solutions of the wave equation under a variety of circumstances. In optics, the LCT can be used to model paraxial free space propagation and other quadratic phase systems such as lens and graded-index media. A number of algorithms have been presented to fast compute the LCT. When they are used to compute the LCT, the sampling period in the transform domain is dependent on that in the signal domain. This drawback limits their applicability in some cases such as color digital holography. In this paper, a Fast-Fourier-Transform-based Direct Integration algorithm(FFT-DI) for the LCT is presented. The FFT-DI is a fast computational method of the Direct Integration(DI) for the LCT. It removes the dependency of the sampling period in the transform domain on that in the signal domain. Simulations and experimental results are presented to validate this idea.
Science Education, Integral Inquiry, Transformation and Possibility
ERIC Educational Resources Information Center
Stack, Sue
2013-01-01
This paper is written in response to Nancy Davis's article "Integral Methodological Pluralism in Science Education Research: Valuing Multiple Perspectives." I use Integral Theory as a framing for this response to explore how it might offer different perspectives and ways of inquiring into Nancy's paper. This process highlights…
Exact Green's function of the Aharonov-Bohm-Coulomb system via the Feynman-Kac formula
NASA Astrophysics Data System (ADS)
Chuu, Der-San; Lin, De-Hone
1999-10-01
The Green's function of the relativistic Aharonov-Bohm-Coulomb system is given by the Feynman-Kac formula. The earlier treatment is based on the multiple-valued transformation of Levi-Civitá. The method used in this contribution involves only the explicit form of a simple Green's function and an explicit path integral is avoided.
Improved digital filters for evaluating Fourier and Hankel transform integrals
Anderson, Walter L.
1975-01-01
New algorithms are described for evaluating Fourier (cosine, sine) and Hankel (J0,J1) transform integrals by means of digital filters. The filters have been designed with extended lengths so that a variable convolution operation can be applied to a large class of integral transforms having the same system transfer function. A f' lagged-convolution method is also presented to significantly decrease the computation time when computing a series of like-transforms over a parameter set spaced the same as the filters. Accuracy of the new filters is comparable to Gaussian integration, provided moderate parameter ranges and well-behaved kernel functions are used. A collection of Fortran IV subprograms is included for both real and complex functions for each filter type. The algorithms have been successfully used in geophysical applications containing a wide variety of integral transforms
Integral Transform Methods: A Critical Review of Various Kernels
NASA Astrophysics Data System (ADS)
Orlandini, Giuseppina; Turro, Francesco
2017-03-01
Some general remarks about integral transform approaches to response functions are made. Their advantage for calculating cross sections at energies in the continuum is stressed. In particular we discuss the class of kernels that allow calculations of the transform by matrix diagonalization. A particular set of such kernels, namely the wavelets, is tested in a model study.
A Transformative Approach to Work Integrated Learning in Legal Education
ERIC Educational Resources Information Center
Babacan, Alperhan; Babacan, Hurriyet
2015-01-01
Purpose: The purpose of this paper is to discuss the current context, scope and problems in the provision of work-integrated learning (WIL) in legal education and how the adoption transformative pedagogies in WIL which is offered in legal education can foster personal and social transformation in addition to enhancing lawyering skills. The paper…
Study of {sup 3}He(e,e{prime}) longitudinal response functions with the integral-transform method
Dobretsov, V.Yu.; Efros, V.D.; Shao, B.
1995-09-01
The method of integral transforms is first applied to study of the {sup 3}He longitudinal response functions. The transforms are calculated from localized bound-state type solutions to an inhomogenous three-body equation. {sup 3}N dynamics and the conventional charge density operator serve as an input. The final-state interaction the contribution of the T = 3/2 final states to the problem suppressed and amounts to about 15%. This might be ascribed to symmetry properties of the final-state wave functions. The contributions of the p-wave N/N interaction and of the Coulomb interaction to the problem are studied and found to amount to several percent. Uncertainties due to different choices of s-wave NN forces are found to be of a similar magnitude. For q = 300 MeV/c, the results obtained agree with experiment. For q = 500 MeV/c, noticeable differences are detected. 20 refs., 3 figs.
Numerical approach to Coulomb gauge QCD
Matevosyan, Hrayr H.; Szczepaniak, Adam P.; Bowman, Patrick O.
2008-07-01
We calculate the ghost two-point function in Coulomb gauge QCD with a simple model vacuum gluon wave function using Monte Carlo integration. This approach extends the previous analytic studies of the ghost propagator with this ansatz, where a ladder-rainbow expansion was unavoidable for calculating the path integral over gluon field configurations. The new approach allows us to study the possible critical behavior of the coupling constant, as well as the Coulomb potential derived from the ghost dressing function. We demonstrate that IR enhancement of the ghost correlator or Coulomb form factor fails to quantitatively reproduce confinement using Gaussian vacuum wave functional.
A dynamic integrated fault diagnosis method for power transformers.
Gao, Wensheng; Bai, Cuifen; Liu, Tong
2015-01-01
In order to diagnose transformer fault efficiently and accurately, a dynamic integrated fault diagnosis method based on Bayesian network is proposed in this paper. First, an integrated fault diagnosis model is established based on the causal relationship among abnormal working conditions, failure modes, and failure symptoms of transformers, aimed at obtaining the most possible failure mode. And then considering the evidence input into the diagnosis model is gradually acquired and the fault diagnosis process in reality is multistep, a dynamic fault diagnosis mechanism is proposed based on the integrated fault diagnosis model. Different from the existing one-step diagnosis mechanism, it includes a multistep evidence-selection process, which gives the most effective diagnostic test to be performed in next step. Therefore, it can reduce unnecessary diagnostic tests and improve the accuracy and efficiency of diagnosis. Finally, the dynamic integrated fault diagnosis method is applied to actual cases, and the validity of this method is verified.
A Dynamic Integrated Fault Diagnosis Method for Power Transformers
Gao, Wensheng; Liu, Tong
2015-01-01
In order to diagnose transformer fault efficiently and accurately, a dynamic integrated fault diagnosis method based on Bayesian network is proposed in this paper. First, an integrated fault diagnosis model is established based on the causal relationship among abnormal working conditions, failure modes, and failure symptoms of transformers, aimed at obtaining the most possible failure mode. And then considering the evidence input into the diagnosis model is gradually acquired and the fault diagnosis process in reality is multistep, a dynamic fault diagnosis mechanism is proposed based on the integrated fault diagnosis model. Different from the existing one-step diagnosis mechanism, it includes a multistep evidence-selection process, which gives the most effective diagnostic test to be performed in next step. Therefore, it can reduce unnecessary diagnostic tests and improve the accuracy and efficiency of diagnosis. Finally, the dynamic integrated fault diagnosis method is applied to actual cases, and the validity of this method is verified. PMID:25685841
New four-dimensional integrals by Mellin-Barnes transform
Allendes, Pedro; Guerrero, Natanael; Kondrashuk, Igor; Notte Cuello, Eduardo A.
2010-05-15
This paper is devoted to the calculation of a special class of integrals by Mellin-Barnes transform. It contains double integrals in the position space in d=4-2{epsilon} dimensions, where {epsilon} is parameter of dimensional regularization. These integrals contribute to the effective action of the N=4 supersymmetric Yang-Mills theory. The integrand is a fraction in which the numerator is the logarithm of the ratio of space-time intervals, and the denominator is the product of powers of space-time intervals. According to the method developed in the previous papers, in order to make use of the uniqueness technique for one of two integrations, we shift exponents in powers in the denominator of integrands by some multiples of {epsilon}. As the next step, the second integration in the position space is done by Mellin-Barnes transform. For normalizing procedure, we reproduce first the known result obtained earlier by Gegenbauer polynomial technique. Then, we make another shift of exponents in powers in the denominator to create the logarithm in the numerator as the derivative with respect to the shift parameter {delta}. We show that the technique of work with the contour of the integral modified in this way by using Mellin-Barnes transform repeats the technique of work with the contour of the integral without such a modification. In particular, all the operations with a shift of contour of integration over complex variables of twofold Mellin-Barnes transform are the same as before the {delta} modification of indices, and even the poles of residues coincide. This confirms the observation made in the previous papers that in the position space all the Green's function of N=4 supersymmetric Yang-Mills theory can be expressed in terms of Usyukina-Davydychev functions.
Efficient Integration of Quantum Mechanical Wave Equations by Unitary Transforms
Bauke, Heiko; Keitel, Christoph H.
2009-08-13
The integration of time dependent quantum mechanical wave equations is a fundamental problem in computational physics and computational chemistry. The energy and momentum spectrum of a wave function imposes fundamental limits on the performance of numerical algorithms for this problem. We demonstrate how unitary transforms can help to surmount these limitations.
The Effects of Integrated Transformational Leadership on Achievement
ERIC Educational Resources Information Center
Boberg, John Eric; Bourgeois, Steven J.
2016-01-01
Purpose: Greater understanding about how variables mediate the relationship between leadership and achievement is essential to the success of reform efforts that hold leaders accountable for student learning. The purpose of this paper is to test a model of integrated transformational leadership including three important school mediators.…
Transforming the Economics Curriculum by Integrating Threshold Concepts
ERIC Educational Resources Information Center
Karunaratne, Prashan Shayanka Mendis; Breyer, Yvonne A.; Wood, Leigh N.
2016-01-01
Purpose: Economics is catering to a diverse student cohort. This cohort needs to be equipped with transformative concepts that students can integrate beyond university. When a curriculum is content-driven, threshold concepts are a useful tool in guiding curriculum re-design. The paper aims to discuss these issues. Design/Methodology/Approach: The…
Complexity estimates based on integral transforms induced by computational units.
Kůrková, Věra
2012-09-01
Integral transforms with kernels corresponding to computational units are exploited to derive estimates of network complexity. The estimates are obtained by combining tools from nonlinear approximation theory and functional analysis together with representations of functions in the form of infinite neural networks. The results are applied to perceptron networks.
Exploring Conditions for Transformative Learning in Work-Integrated Education
ERIC Educational Resources Information Center
McRae, Norah
2015-01-01
A qualitative study was undertaken that explored the conditions for transformative learning in cooperative education as a form of work-integrated learning (WIL), towards the development of a theoretical model. Four case studies were analyzed based on interviews with WIL students, supervisors and their co-op coordinator. The findings revealed that…
Transformational leadership and team innovation: integrating team climate principles.
Eisenbeiss, Silke A; van Knippenberg, Daan; Boerner, Sabine
2008-11-01
Fostering team innovation is increasingly an important leadership function. However, the empirical evidence for the role of transformational leadership in engendering team innovation is scarce and mixed. To address this issue, the authors link transformational leadership theory to principles of M. A. West's (1990) team climate theory and propose an integrated model for the relationship between transformational leadership and team innovation. This model involves support for innovation as a mediating process and climate for excellence as a moderator. Results from a study of 33 research and development teams confirmed that transformational leadership works through support for innovation, which in turn interacts with climate for excellence such that support for innovation enhances team innovation only when climate for excellence is high.
Wang, Bin; Gao, Yongsheng
2016-12-01
In this paper, we present a novel mathematical tool, Structure Integral Transform (SIT), for invariant shape description and recognition. Different from the Radon Transform (RT), which integrates the shape image function over a 1D line in the image plane, the proposed SIT builds upon two orthogonal integrals over a 2D K -cross dissecting structure spanning across all rotation angles by which the shape regions are bisected in each integral. The proposed SIT brings the following advantages over the RT: 1) it has the extra function of describing the interior structural relationship within the shape which provides a more powerful discriminative ability for shape recognition; 2) the shape regions are dissected by the K -cross in a coarse to fine hierarchical order that can characterize the shape in a better spatial organization scanning from the center to the periphery; and 3) it is easier to build a completely invariant shape descriptor. The experimental results of applying SIT to shape recognition demonstrate its superior performance over the well-known Radon transform, and the well-known shape contexts and the polar harmonic transforms.
Hughto, J.; Schneider, A. S.; Horowitz, C. J.; Berry, D. K.
2011-07-15
Diffusion in Coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants D from molecular dynamics simulations. We find that D for Coulomb crystals with relatively soft-core 1/r interactions may be larger than D for Lennard-Jones or other solids with harder-core interactions. Diffusion, for simulations of nearly perfect body-centered-cubic lattices, involves the exchange of ions in ringlike configurations. Here ions ''hop'' in unison without the formation of long lived vacancies. Diffusion, for imperfect crystals, involves the motion of defects. Finally, we find that diffusion, for an amorphous system rapidly quenched from Coulomb parameter {Gamma}=175 to Coulomb parameters up to {Gamma}=1750, is fast enough that the system starts to crystalize during long simulation runs. These results strongly suggest that Coulomb solids in cold white dwarf stars, and the crust of neutron stars, will be crystalline and not amorphous.
Diffusion in Coulomb crystals.
Hughto, J; Schneider, A S; Horowitz, C J; Berry, D K
2011-07-01
Diffusion in Coulomb crystals can be important for the structure of neutron star crusts. We determine diffusion constants D from molecular dynamics simulations. We find that D for Coulomb crystals with relatively soft-core 1/r interactions may be larger than D for Lennard-Jones or other solids with harder-core interactions. Diffusion, for simulations of nearly perfect body-centered-cubic lattices, involves the exchange of ions in ringlike configurations. Here ions "hop" in unison without the formation of long lived vacancies. Diffusion, for imperfect crystals, involves the motion of defects. Finally, we find that diffusion, for an amorphous system rapidly quenched from Coulomb parameter Γ=175 to Coulomb parameters up to Γ=1750, is fast enough that the system starts to crystalize during long simulation runs. These results strongly suggest that Coulomb solids in cold white dwarf stars, and the crust of neutron stars, will be crystalline and not amorphous.
Implementing quantum Fourier transform with integrated photonic devices
NASA Astrophysics Data System (ADS)
Tabia, Gelo Noel
2014-03-01
Many quantum algorithms that exhibit exponential speedup over their classical counterparts employ the quantum Fourier transform, which is used to solve interesting problems such as prime factorization. Meanwhile, nonclassical interference of single photons achieved on integrated platforms holds the promise of achieving large-scale quantum computation with multiport devices. An optical multiport device can be built to realize any quantum circuit as a sequence of unitary operations performed by beam splitters and phase shifters on path-encoded qudits. In this talk, I will present a recursive scheme for implementing quantum Fourier transform with a multimode interference photonic integrated circuit. Research at Perimeter Institute is supported by the Government of Canada through Industry Canada and by the Province of Ontario through the Ministry of Research and Innovation.
Linearization properties, first integrals, nonlocal transformation for heat transfer equation
NASA Astrophysics Data System (ADS)
Orhan, Özlem; Özer, Teoman
2016-08-01
We examine first integrals and linearization methods of the second-order ordinary differential equation which is called fin equation in this study. Fin is heat exchange surfaces which are used widely in industry. We analyze symmetry classification with respect to different choices of thermal conductivity and heat transfer coefficient functions of fin equation. Finally, we apply nonlocal transformation to fin equation and examine the results for different functions.
Greater benefits of multisensory integration during complex sensorimotor transformations.
Buchholz, Verena N; Goonetilleke, Samanthi C; Medendorp, W Pieter; Corneil, Brian D
2012-06-01
Multisensory integration enables rapid and accurate behavior. To orient in space, sensory information registered initially in different reference frames has to be integrated with the current postural information to produce an appropriate motor response. In some postures, multisensory integration requires convergence of sensory evidence across hemispheres, which would presumably lessen or hinder integration. Here, we examined orienting gaze shifts in humans to visual, tactile, or visuotactile stimuli when the hands were either in a default uncrossed posture or a crossed posture requiring convergence across hemispheres. Surprisingly, we observed the greatest benefits of multisensory integration in the crossed posture, as indexed by reaction time (RT) decreases. Moreover, such shortening of RTs to multisensory stimuli did not come at the cost of increased error propensity. To explain these results, we propose that two accepted principles of multisensory integration, the spatial principle and inverse effectiveness, dynamically interact to aid the rapid and accurate resolution of complex sensorimotor transformations. First, early mutual inhibition of initial visual and tactile responses registered in different hemispheres reduces error propensity. Second, inverse effectiveness in the integration of the weakened visual response with the remapped tactile representation expedites the generation of the correct motor response. Our results imply that the concept of inverse effectiveness, which is usually associated with external stimulus properties, might extend to internal spatial representations that are more complex given certain body postures.
Singular integrals related to the Radon transform and boundary value problems.
Phong, D H; Stein, E M
1983-12-01
Two classes of integral operators are introduced that combine features of Calderón-Zygmund singular integrals, the Hilbert integral, and the Radon transform. Examples and applications arising from integral geometry and several complex variables are discussed.
Singular integrals related to the Radon transform and boundary value problems
Phong, D. H.; Stein, E. M.
1983-01-01
Two classes of integral operators are introduced that combine features of Calderón—Zygmund singular integrals, the Hilbert integral, and the Radon transform. Examples and applications arising from integral geometry and several complex variables are discussed. PMID:16593402
Federal Register 2010, 2011, 2012, 2013, 2014
2011-10-14
... Transformation--Automated Integrated Operating Environment (IOE), New Information Collection; Comment Request... information collection request for the Automated Integrated Operating Environment (IOE). The comment...
New approach to folding with the Coulomb wave function
Blokhintsev, L. D.; Savin, D. A.; Kadyrov, A. S.; Mukhamedzhanov, A. M.
2015-05-15
Due to the long-range character of the Coulomb interaction theoretical description of low-energy nuclear reactions with charged particles still remains a formidable task. One way of dealing with the problem in an integral-equation approach is to employ a screened Coulomb potential. A general approach without screening requires folding of kernels of the integral equations with the Coulomb wave. A new method of folding a function with the Coulomb partial waves is presented. The partial-wave Coulomb function both in the configuration and momentum representations is written in the form of separable series. Each term of the series is represented as a product of a factor depending only on the Coulomb parameter and a function depending on the spatial variable in the configuration space and the momentum variable if the momentum representation is used. Using a trial function, the method is demonstrated to be efficient and reliable.
Experimental Evaluation of Integral Transformations for Engineering Drawings Vectorization
NASA Astrophysics Data System (ADS)
Vaský, Jozef; Gramblička, Matúš
2014-12-01
The concept of digital manufacturing supposes application of digital technologies in the whole product life cycle. Direct digital manufacturing includes such information technology processes, where products are directly manufactured from 3D CAD model. In digital manufacturing, engineering drawing is replaced by CAD product model. In the contemporary practice, lots of engineering paper-based drawings are still archived. They could be digitalized by scanner and stored to one of the raster graphics format and after that vectorized for interactive editing in the specific software system for technical drawing or for archiving in some of the standard vector graphics file format. The vector format is suitable for 3D model generating, too.The article deals with using of selected integral transformations (Fourier, Hough) in the phase of digitalized raster engineering drawings vectorization.
Solution of Coulomb system in momentum space
Lin, D.-H.
2008-02-15
The solution of D-dimensional Coulomb system is solved in momentum space by path integral. From which the topological effect of a magnetic flux in the system is given. It is revealed that the flux effect represented by the two-dimensional field of Aharonov-Bohm covers any space-dimensions.
NASA Astrophysics Data System (ADS)
Militzer, Burkhard
2003-06-01
Path integral Monte Carlo simulations have been used to study deuterium at high pressure and temperature. The equation of state has been derived in the temperature and density regions of 10 000 leq T leq 1 000 000 K and 0.6 leq rho leq 2.5 g cm-3. A series of shock Hugoniot curves is computed for different initial compressions in order to compare with current and future shock wave experiments using liquid deuterium samples precompressed in diamond anvil cells. Submitted to Proceedings of the Conference on Strongly Coupled Coulomb Systems 2002 in Santa Fe.
Coulomb gauge ghost propagator and the Coulomb form factor
NASA Astrophysics Data System (ADS)
Quandt, M.; Burgio, G.; Chimchinda, S.; Reinhardt, H.
The ghost propagator and the Coulomb potential are evaluated in Coulomb gauge on the lattice, using an improved gauge fixing scheme which includes the residual symmetry. This setting has been shown to be essential in order to explain the scaling violations in the instantaneous gluon propagator. We find that both the ghost propagator and the Coulomb potential are insensitive to the Gribov problem or the details of the residual gauge fixing, even if the Coulomb potential is evaluated from the A0 -propagator instead of the Coulomb kernel. In particular, no signs of scaling violations could be found in either quantity, at least to well below the numerical accuracy where these violations were visible for the gluon propagator. The Coulomb potential from the A0 -propagator is shown to be in qualitative agreement with the (formally equivalent) expression evaluated from the Coulomb kernel.
Learning Multisensory Integration and Coordinate Transformation via Density Estimation
Sabes, Philip N.
2013-01-01
Sensory processing in the brain includes three key operations: multisensory integration—the task of combining cues into a single estimate of a common underlying stimulus; coordinate transformations—the change of reference frame for a stimulus (e.g., retinotopic to body-centered) effected through knowledge about an intervening variable (e.g., gaze position); and the incorporation of prior information. Statistically optimal sensory processing requires that each of these operations maintains the correct posterior distribution over the stimulus. Elements of this optimality have been demonstrated in many behavioral contexts in humans and other animals, suggesting that the neural computations are indeed optimal. That the relationships between sensory modalities are complex and plastic further suggests that these computations are learned—but how? We provide a principled answer, by treating the acquisition of these mappings as a case of density estimation, a well-studied problem in machine learning and statistics, in which the distribution of observed data is modeled in terms of a set of fixed parameters and a set of latent variables. In our case, the observed data are unisensory-population activities, the fixed parameters are synaptic connections, and the latent variables are multisensory-population activities. In particular, we train a restricted Boltzmann machine with the biologically plausible contrastive-divergence rule to learn a range of neural computations not previously demonstrated under a single approach: optimal integration; encoding of priors; hierarchical integration of cues; learning when not to integrate; and coordinate transformation. The model makes testable predictions about the nature of multisensory representations. PMID:23637588
Feynman rules for Coulomb gauge QCD
Andrasi, A.; Taylor, J.C.
2012-10-15
The Coulomb gauge in nonabelian gauge theories is attractive in principle, but beset with technical difficulties in perturbation theory. In addition to ordinary Feynman integrals, there are, at 2-loop order, Christ-Lee (CL) terms, derived either by correctly ordering the operators in the Hamiltonian, or by resolving ambiguous Feynman integrals. Renormalization theory depends on the sub-graph structure of ordinary Feynman graphs. The CL terms do not have a sub-graph structure. We show how to carry out renormalization in the presence of CL terms, by re-expressing these as 'pseudo-Feynman' integrals. We also explain how energy divergences cancel. - Highlights: Black-Right-Pointing-Pointer In Coulomb gauge QCD, we re-express Christ-Lee terms in the Hamiltonian as pseudo-Feynman integrals. Black-Right-Pointing-Pointer This gives a subgraph structure, and allows the ordinary renormalization process. Black-Right-Pointing-Pointer It also leads to cancellation of energy-divergences.
Federal Register 2010, 2011, 2012, 2013, 2014
2011-03-28
... Transformation--Automated Integrated Operating Environment (IOE), New Information Collection; Comment Request... Operating Environment (IOE); OMB Control No. 1615-NEW. SUMMARY: USCIS is developing an automated Integrated Operating Environment (IOE) to process benefit applications. The IOE will collect information by...
2001-03-01
A unique ASIC was designed implementing the Haar Wavelet transform for image compression/decompression. ASIC operations include performing the Haar... wavelet transform on a 512 by 512 square pixel image, preparing the image for transmission by quantizing and thresholding the transformed data, and...performing the inverse Haar wavelet transform , returning the original image with only minor degradation. The ASIC is based on an existing four-chip FPGA
Polonyi, J.
2008-06-15
The contribution of different modes of the Coulomb field to decoherence and to the dynamical breakdown of the time reversal invariance is calculated in the one-loop approximation for nonrelativistic electron gas. The dominant contribution was found to come from the usual collective modes in the plasma, namely, the zero-sound and the plasmon oscillations. The length scale of the quantum-classical transition is found to be close to the Thomas-Fermi screening length. It is argued that the extension of these modes to the whole Fock space yields optimal pointer states.
An integro-differential transform to analytically reduce H2 molecular integrals
NASA Astrophysics Data System (ADS)
Straton, Jack
2012-06-01
Molecular integrals that have a coordinate dependence akin to the bonding H2 wave function are often carried out one-by-one, using hyper-spherical coordinates [1], Jacobi coordinates or bond-length coordinates [2], or confocal ellipsoidal coordinates [3]. An alternative strategy is to extend the general result developed by the author [4] for evaluating integrals of any number of products of multicenter ground-state or excited [5] atomic wave functions, Coulomb or Yukawa potentials, and Coulomb-waves [6] to include the H2 molecular wave function. Modifications for semi-infinite integrals that terminate on a surface such as a Scanning Tunneling Microscope sample are also discussed. [4pt] [1] Y. Zhou, C. D. Lin and J. Shertzer, J. Phys. B: At. Mol. Opt. Phys. 26, 3937-3949 (1993).[0pt] [2] J. M. Hutson and P. Soldan, International Reviews in Physical Chemistry, 26(1) 1 - 28 (January 2007).[0pt] [3] J. P. Grivet, J. Chem. Educ., 79(1), 127 (2002).[0pt] [4] Jack C. Straton, Phys. Rev. A 39, 1676-84 (1989); Erratum Phys. Rev. A 40, 2819 (1989).[0pt] [5] Jack C. Straton, Phys. Rev. A 41, 71-7 (1990).[0pt] [6] Jack C. Straton, Phys. Rev. A 42, 307-10 (1990).
NASA Astrophysics Data System (ADS)
Gaughan, Daniel J.
1990-12-01
This research was performed in order to develop a superior processing schedule for fabricating wafer-scale integration (WSI) circuit modules. This technology allows the design of circuitry that spans the entire surface of a silicon substrate wafer. The circuit element employed in this research was the Hilbert transform, a digital phase-shifting circuit. The transform was incorporated into a three integrated circuit (IC) die package that consisted of a mechanically supportive silicon wafer, three IC die, and a planarizing silicon wafer. The die were epoxied into this wafer using a Teflon block as a flat, and the combination was epoxied onto the substrate wafer, forming the IC module. The original design goals of this research were to keep the IC die and wafer planar and to electrically characterize of the module's interconnections. The first goal was met; the resultant process uses a low temperature (50 C) cure to achieve die-to-wafer planarity of within 5 microns. The second was not met due to the inability to pattern the chosen photosensitive dielectric material. Recommendations for further research included the need to use a stable non-stick surface as a epoxy cure fixture and the need to investigate the photopatternable dielectric material.
Ziegler, Brittany; Montplaisir, Lisa
2012-12-01
A shift is currently taking place in which explicit connections between content are being emphasized. Biology is not an isolated discipline, yet undergraduate courses frequently focus on discrete knowledge. Students often engage in rote learning, struggle with transforming and applying content. Integrative thinking occurs when students recognize connections to content. Written reflections provide students with the opportunity to demonstrate this thinking. We transformed student-written reflections into concept webs to gain insights into how students connect biological concepts. We were interested in determining if characteristics of integrative thinking develop through reflections. The results indicate a significant relationship between concepts and integrated relationships. Integrative thinking varied but declined overall. Concept webs allow for an examination of student integrative thinking through the transformation of reflection and provide insights into the connections and relationships that students draw between biological concepts. Reflections can transform learning by facilitating and allowing for the evaluation of integrative thinking.
Traceable Coulomb blockade thermometry
NASA Astrophysics Data System (ADS)
Hahtela, O.; Mykkänen, E.; Kemppinen, A.; Meschke, M.; Prunnila, M.; Gunnarsson, D.; Roschier, L.; Penttilä, J.; Pekola, J.
2017-02-01
We present a measurement and analysis scheme for determining traceable thermodynamic temperature at cryogenic temperatures using Coulomb blockade thermometry. The uncertainty of the electrical measurement is improved by utilizing two sampling digital voltmeters instead of the traditional lock-in technique. The remaining uncertainty is dominated by that of the numerical analysis of the measurement data. Two analysis methods are demonstrated: numerical fitting of the full conductance curve and measuring the height of the conductance dip. The complete uncertainty analysis shows that using either analysis method the relative combined standard uncertainty (k = 1) in determining the thermodynamic temperature in the temperature range from 20 mK to 200 mK is below 0.5%. In this temperature range, both analysis methods produced temperature estimates that deviated from 0.39% to 0.67% from the reference temperatures provided by a superconducting reference point device calibrated against the Provisional Low Temperature Scale of 2000.
The Impact of Technology Integration through a Transformative Approach
ERIC Educational Resources Information Center
Cubillos, Jo Ann
2013-01-01
The integration of technology into classroom instruction in K-12 schools remains problematic. The problems associated with this integration are troubling, as technology integration may change a teacher's pedagogy toward more innovative approaches that increase student achievement. The purpose of this study was to document teachers' experiences as…
Energies of Screened Coulomb Potentials.
ERIC Educational Resources Information Center
Lai, C. S.
1979-01-01
This article shows that, by applying the Hellman-Feynman theorem alone to screened Coulomb potentials, the first four coefficients in the energy series in powers of the perturbation parameter can be obtained from the unperturbed Coulomb system. (Author/HM)
Coulomb blockade and Coulomb staircase behavior observed at room temperature
NASA Astrophysics Data System (ADS)
Uky Vivitasari, Pipit; Azuma, Yasuo; Sakamoto, Masanori; Teranishi, Toshiharu; Majima, Yutaka
2017-02-01
A single-electron transistor (SET) consists of source, drain, Coulomb island, and gate to modulate the number of electrons and control the current. For practical applications, it is important to operate a SET at room temperature. One proposal towards the ability to operate at room temperature is to decrease Coulomb island size down to a few nanometres. We investigate a SET using Sn-porphyrin (Sn-por) protected gold nanoparticles (AuNPs) with 1.4 nm in core diameter as a Coulomb island. The fabrication method of nanogap electrodes uses the combination of a top-down technique by electron beam lithography (EBL) and a bottom-up process through electroless gold plating (ELGP) as our group have described before. The electrical measurement was conducted at room temperature (300 K). From current–voltage (I d–V d) characteristics, we obtained clear Coulomb blockade phenomena together with a Coulomb staircase due to a Sn-por protected gold NP as a Coulomb island. Experimental results of I d–V d characteristics agree with a theoretical curve based on using the orthodox model. Clear dI d/dV d peaks are observed in the Coulomb staircase at 9 K which suggest the electron transports through excited energy levels of Au NPs. These results are a big step for obtaining SETs that can operate at room temperature.
Solution of fractional kinetic equation by a class of integral transform of pathway type
NASA Astrophysics Data System (ADS)
Kumar, Dilip
2013-04-01
Solutions of fractional kinetic equations are obtained through an integral transform named Pα-transform introduced in this paper. The Pα-transform is a binomial type transform containing many class of transforms including the well known Laplace transform. The paper is motivated by the idea of pathway model introduced by Mathai [Linear Algebra Appl. 396, 317-328 (2005), 10.1016/j.laa.2004.09.022]. The composition of the transform with differential and integral operators are proved along with convolution theorem. As an illustration of applications to the general theory of differential equations, a simple differential equation is solved by the new transform. Being a new transform, the Pα-transform of some elementary functions as well as some generalized special functions such as H-function, G-function, Wright generalized hypergeometric function, generalized hypergeometric function, and Mittag-Leffler function are also obtained. The results for the classical Laplace transform is retrieved by letting α → 1.
ERIC Educational Resources Information Center
Chatterjee, B.; Dey, D.; Chakravorti, S.
2010-01-01
The development of integrated, portable, transformer condition monitoring (TCM) equipment for classroom demonstrations as well as for student exercises conducted in the field is discussed. Demonstrations include experimentation with real-world transformers to illustrate concepts such as polarization and depolarization current through oil-paper…
Integration of planar transformer and/or planar inductor with power switches in power converter
Chen, Kanghua; Ahmed, Sayeed; Zhu, Lizhi
2007-10-30
A power converter integrates at least one planar transformer comprising a multi-layer transformer substrate and/or at least one planar inductor comprising a multi-layer inductor substrate with a number of power semiconductor switches physically and thermally coupled to a heat sink via one or more multi-layer switch substrates.
ERIC Educational Resources Information Center
Roth, George
2004-01-01
Reflection upon a field study of a corporate transformation provides insights into the application and integration of organizational learning theory and frameworks with local, corporate knowledge. In the corporate transformation studied this local knowledge came from consumer psychology, marketing campaigns and the use of media. When these ideas…
Renormalization in the Coulomb gauge and order parameter for confinement in QCD
NASA Astrophysics Data System (ADS)
Zwanziger, Daniel
1998-05-01
Renormalization of the Coulomb gauge is studied in the phase space formalism, where one integrates over both the vector potential A, and its canonical momentum Π as well as the usual Faddeev-Popov auxiliary fields. A proof of renormalizability is not attempted. Instead, algebraic identities are derived from BRST invariance which renormalization must satisfy if the Coulomb gauge is renormalizable. In particular, a Ward identity is derived which holds at a fixed time t, and which is an analog of Gauss's law in the BRST formalism, and which we call the Gauss-BRST identity. The familiar Zinn-Justin equation results when this identity is integrated over all t. It is shown that in the Coulomb gauge, g2D0.0 is a renormalization-group invariant, as is its instantaneous part V( R), which we call the color-Coulomb potential. (Here D0.0 is the time-time component of the gluon propagator.) The contribution of V( R) to the Wilson loop exponentiates. It is proposed that the string tension defined by KCoul = lim R→∞ CV( R)/ R may serve as an order parameter for confinement, where C = (2 N) -1( N2 - 1) for SU( N) gauge theory. A remarkable consequence of the above-mentioned Ward identity is that the Fourier transform V( k) of V( R) is of the product form V( k) = [ k2D C,C ∗ ( k)] 2L( k) , where D C,C ∗ ( k) is the ghost propagator, and L( k) is a correlation function of longitudinal gluons. This exact equation combines with a previous analysis of the Gribov problem according to which k2D C,C ∗ ( k) diverges at k = 0 , to provide a scenario for confinement.
Coulomb excitation of radioactive nuclear beams in inverse kinematics
Zamfir, N.V. |||; Barton, C.J.; Brenner, D.S.; Casten, R.F. |; Gill, R.L.; Zilges, A. |
1996-12-31
Techniques for the measurement of B (E2:0{sub 1}{sup +} {r_arrow} 2{sub 1}{sup +}) values by Coulomb excitation of Radioactive Nuclear Beams in inverse kinematics are described. Using a thin, low Z target, the Coulomb excited beam nuclei will decay in flight downstream of the target. For long lifetimes (nanosecond range) these nuclei decay centimeters downstream of the target and for shorter lifetimes (picoseconds or less) they decay near the target. Corresponding to these two lifetime regimes two methods have been developed to measure {gamma} rays from the Coulomb excited nuclei: the lifetime method in which the lifetime of the excited state is deduced from the decay curve and the integral method in which the B(E2) value is extracted from the measured total Coulomb excitation cross section.
Laplace transform approach for solving integral equations using computer algebra system
NASA Astrophysics Data System (ADS)
Paneva-Konovska, Jordanka; Nikolova, Yanka
2016-12-01
The Laplace transform method, along with Computer Algebra Systems (CAS) "Maple" v. 13, are extremely successfully applied for solving a class of integral equations with an arbitrary order, including fractional order integral equations. The combining of both powerful approaches allows students more quickly, enjoyable and thoroughly to master the material.
Transforming Academic Nursing: From Balance through Integration to Coherence.
ERIC Educational Resources Information Center
Langston, Nancy F.; Cowling, W. Richard, III; McCain, Nancy L.
1999-01-01
The academic mission should move from teaching-research-service to a holistic model with a single, integrative focus on knowledge work. The unity of knowledge development, dissemination, and application by a community of scholars promotes coherence at the university, unit, and scholar level. (SK)
Transforming Water Management: an Emerging Promise of Integrated Earth Observations
NASA Astrophysics Data System (ADS)
Lawford, R. G.
2011-12-01
Throughout its history, civilization has relied on technology to facilitate many of its advances. New innovations and technologies have often provided strategic advantages that have led to transformations in institutions, economies and ultimately societies. Observational and information technologies are leading to significant developments in the water sector. After a brief introduction tracing the role of observational technologies in the areas of hydrology and water cycle science, this talk explores the existing and potential contributions of remote sensing data in water resource management around the world. In particular, it outlines the steps being undertaken by the Group on Earth Observations (GEO) and its Water Task to facilitate capacity building efforts in water management using Earth Observations in Asia, Africa and Latin and Caribbean America. Success stories on the benefits of using Earth Observations and applying GEO principles are provided. While GEO and its capacity building efforts are contributing to the transformation of water management through interoperability, data sharing, and capacity building, the full potential of these contributions has not been fully realized because impediments and challenges still remain.
NASA Astrophysics Data System (ADS)
Krasilenko, Vladimir G.; Nikolsky, Alexander I.; Lazarev, Alexander A.; Lazareva, Maria V.
2008-03-01
In the paper the actuality of neurophysiologically motivated neuron arrays with flexibly programmable functions and operations with possibility to select required accuracy and type of nonlinear transformation and learning are shown. We consider neurons design and simulation results of multichannel spatio-time algebraic accumulation - integration of optical signals. Advantages for nonlinear transformation and summation - integration are shown. The offered circuits are simple and can have intellectual properties such as learning and adaptation. The integrator-neuron is based on CMOS current mirrors and comparators. The performance: consumable power - 100...500 μW, signal period- 0.1...1ms, input optical signals power - 0.2...20 μW time delays - less 1μs, the number of optical signals - 2...10, integration time - 10...100 of signal periods, accuracy or integration error - about 1%. Various modifications of the neuron-integrators with improved performance and for different applications are considered in the paper.
Pérez, Alejandro; von Lilienfeld, O Anatole
2011-08-09
Thermodynamic integration, perturbation theory, and λ-dynamics methods were applied to path integral molecular dynamics calculations to investigate free energy differences due to "alchemical" transformations. Several estimators were formulated to compute free energy differences in solvable model systems undergoing changes in mass and/or potential. Linear and nonlinear alchemical interpolations were used for the thermodynamic integration. We find improved convergence for the virial estimators, as well as for the thermodynamic integration over nonlinear interpolation paths. Numerical results for the perturbative treatment of changes in mass and electric field strength in model systems are presented. We used thermodynamic integration in ab initio path integral molecular dynamics to compute the quantum free energy difference of the isotope transformation in the Zundel cation. The performance of different free energy methods is discussed.
NASA Astrophysics Data System (ADS)
Cai, Huiying; Zhu, Feng; Hao, Yingming; Lu, Rongrong
2016-10-01
Shape Matching under Affine Transformation (SMAT) is an important issue in shape analysis. Most of the existing SMAT methods are sensitive to noise or complicated because they usually need to extract the edge points or compute the high order function of the shape. To solve these problems, a new SMAT method which combines the low order shape normalization and the multi-scale area integral features is proposed. First, the shapes with affine transformation are normalized into their orthogonal representations according to the moments and an equivalent resample. This procedure transforms the shape by several linear operations: translations, scaling, and rotation, following by a resample operation. Second, the Multi-Scale Area Integral Features (MSAIF) of the shapes which are invariant to the orthogonal transformation (rotation and reflection transformation) are extracted. The MSAIF is a signature achieved through concatenating the area integral feature at a range of scales from fine to coarse. The area integral feature is an integration of the feature values, which are computed by convoluting the shape with an isotropic kernel and taking the complement, over the shape domain following by the normalization using the area of the shape. Finally, the matching of different shapes is performed according to the dissimilarity which is measured with the optimal transport distance. The performance of the proposed method is tested on the car dataset and the multi-view curve dataset. Experimental results show that the proposed method is efficient and robust, and can be used in many shape analysis works.
Integrative Approach for a Transformative Freshman-Level STEM Curriculum
Curran, Kathleen L.; Olsen, Paul E.; Nwogbaga, Agashi P.; Stotts, Stephanie
2016-01-01
In 2014 Wesley College adopted a unified undergraduate program of evidence-based high-impact teaching practices. Through foundation and federal and state grant support, the college completely revised its academic core curriculum and strengthened its academic support structures by including a comprehensive early alert system for at-risk students. In this core, science, technology, engineering, and mathematics (STEM) faculty developed fresh manifestations of integrated concept-based introductory courses and revised upper-division STEM courses around student-centered learning. STEM majors can participate in specifically designed paid undergraduate research experiences in directed research elective courses. Such a college-wide multi-tiered approach results in institutional cultural change. PMID:27064213
Radiative capture versus Coulomb dissociation.
Esbensen, H.; Physics
2006-01-01
Measurements of the Coulomb dissociation of {sup 8}B have been used to infer the rate of the inverse radiative proton capture on {sup 7}Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed.
Stratified flow over a backward-facing step: hybrid solution by integral transforms
NASA Astrophysics Data System (ADS)
Ramos, R.; Perez Guerrero, J. S.; Cotta, R. M.
2001-01-01
The generalized integral transform technique (GITT) is employed in the hybrid numerical-analytical solution of the stratified backward-facing step flow problem, with automatic global accuracy control towards a user-prescribed accuracy target. The present paper is aimed at extending the available database on benchmark results in heat and fluid flow, which were progressively obtained through integral transforms, for the co-validation of more flexible fully discrete approaches. Numerical results are presented for the situations more frequently encountered in the literature Copyright
NASA Astrophysics Data System (ADS)
Ji, Jia-Liang; Zhu, Zuo-Nong
2017-01-01
Very recently, Ablowitz and Musslimani introduced a new integrable nonlocal nonlinear Schrödinger equation. In this paper, we investigate an integrable nonlocal modified Korteweg-de Vries equation (mKdV) which can be derived from the well-known AKNS system. We construct the Darboux transformation for the nonlocal mKdV equation. Using the Darboux transformation, we obtain its different kinds of exact solutions including soliton, kink, antikink, complexiton, rogue-wave solution, and nonlocalized solution with singularities. It is shown that these solutions possess new properties which are different from the ones for mKdV equation.
Room temperature Coulomb blockade mediated field emission via self-assembled gold nanoparticles
NASA Astrophysics Data System (ADS)
Wang, Fei; Fang, Jingyue; Chang, Shengli; Qin, Shiqiao; Zhang, Xueao; Xu, Hui
2017-02-01
Coulomb blockade mediated field-emission current was observed in single-electron tunneling devices based on self-assembled gold nanoparticles at 300 K. According to Raichev's theoretical model, by fixing a proper geometric distribution of source, island and drain, the transfer characteristics can be well explained through a combination of Coulomb blockade and field emission. Coulomb blockade and field emission alternately happen in our self-assembled devices. The Coulomb island size derived from the experimental data is in good agreement with the average size of the gold nanoparticles used in the device. The integrated tunneling can be adjusted via a gate electrode.
Helicity is the only integral invariant of volume-preserving transformations
Enciso, Alberto; Peralta-Salas, Daniel; de Lizaur, Francisco Torres
2016-01-01
We prove that any regular integral invariant of volume-preserving transformations is equivalent to the helicity. Specifically, given a functional ℐ defined on exact divergence-free vector fields of class C1 on a compact 3-manifold that is associated with a well-behaved integral kernel, we prove that ℐ is invariant under arbitrary volume-preserving diffeomorphisms if and only if it is a function of the helicity. PMID:26864201
Helicity is the only integral invariant of volume-preserving transformations.
Enciso, Alberto; Peralta-Salas, Daniel; de Lizaur, Francisco Torres
2016-02-23
We prove that any regular integral invariant of volume-preserving transformations is equivalent to the helicity. Specifically, given a functional I defined on exact divergence-free vector fields of class C(1) on a compact 3-manifold that is associated with a well-behaved integral kernel, we prove that I is invariant under arbitrary volume-preserving diffeomorphisms if and only if it is a function of the helicity.
A system for multi-locus chromosomal integration and transformation-free selection marker rescue
Siddiqui, Michael S.; Choksi, Atri; Smolke, Christina D.
2014-01-01
Yeast integrating plasmids (YIPs) are a versatile tool for stable integration in Saccharomyces cerevisiae. However, current YIP systems necessitate time- and labor-intensive methods for cloning and selection marker rescue. Here we describe the design, construction, and validation of a new YIP system capable of accelerating the stable integration of multiple expression constructs into different loci in the yeast S. cerevisiae. These “directed pop-out” plasmids enable a simple, two-step integration protocol that results in a scarless integration alongside a complete rescue of the selection marker. These plasmids combine three key features: a dedicated “YIPout” fragment directs a recombination event that rescues the selection marker while avoiding undesired excision of the target DNA sequence, a multi-fragment modular DNA assembly system simplifies cloning, and a new set of counterselectable markers enables serial integration followed by a transformation-free marker rescue event. We constructed and tested directed pop-out YIPs for integration of fluorescent reporter genes into four yeast loci. We validated our new YIP design by integrating three reporter genes into three different loci with transformation-free rescue of selection markers. These new YIP designs will facilitate the construction of yeast strains that express complex heterologous metabolic pathways. PMID:25226817
Integrated Environmental Modeling (IEM) systems that account for the fate/transport of organics frequently require physicochemical properties as well as transformation products. A myriad of chemical property databases exist but these can be difficult to access and often do not co...
ERIC Educational Resources Information Center
Wetzel, David R.
The purpose of this study was to determine the effects of an implementation plan that would support middle school science teachers as they integrated a specific technological tool, Calculator-Based Laboratory (CBL) probeware. The final goal of the implementation process was pedagogical and curricula transformation by the participants. The…
2015-10-01
interactive data visualizations designed to transform and consolidate complex multimodal physiological data into integrated interactive displays will...accomplishments include: 1) Devised methods to both filter and interpolate physiological data, 2) Created physiologic indices for clinically meaningful...variation among several parameters using a version of empirical orthogonal functions, 3) Applied the above physiologic indices to create a patient
Integrated Environmental Modeling (IEM) systems that account for the fate/transport of organics frequently require physicochemical properties as well as transformation products. A myriad of chemical property databases exist but these can be difficult to access and often do not co...
Using the Screened Coulomb Potential to Illustrate the Variational Method
ERIC Educational Resources Information Center
Zuniga, Jose; Bastida, Adolfo; Requena, Alberto
2012-01-01
The screened Coulomb potential, or Yukawa potential, is used to illustrate the application of the single and linear variational methods. The trial variational functions are expressed in terms of Slater-type functions, for which the integrals needed to carry out the variational calculations are easily evaluated in closed form. The variational…
Phillips, Andrew B; Merrill, Jacqueline A
2015-12-01
Healthcare is in a period significant transformational activity through the accelerated adoption of healthcare technologies, new reimbursement systems that emphasize shared savings and care coordination, and the common place use of mobile technologies by patients, providers, and others. The complexity of healthcare creates barriers to transformational activity and has the potential to inhibit the desired paths toward change envisioned by policymakers. Methods for understanding how change is occurring within this complex environment are important to the evaluation of delivery system reform and the role of technology in healthcare transformation. This study examines the use on an integrative review methodology to evaluate the healthcare literature for evidence of technology transformation in healthcare. The methodology integrates the evaluation of a broad set of literature with an established evaluative framework to develop a more complete understanding of a particular topic. We applied this methodology and the framework of punctuated equilibrium (PEq) to the analysis of the healthcare literature from 2004 to 2012 for evidence of technology transformation, a time during which technology was at the forefront of healthcare policy. The analysis demonstrated that the established PEq framework applied to the literature showed considerable potential for evaluating the progress of policies that encourage healthcare transformation. Significant inhibitors to change were identified through the integrative review and categorized into ten themes that describe the resistant structure of healthcare delivery: variations in the environment; market complexity; regulations; flawed risks and rewards; change theories; barriers; ethical considerations; competition and sustainability; environmental elements, and internal elements. We hypothesize that the resistant nature of the healthcare system described by this study creates barriers to the direct consumer involvement and engagement
LACKS,S.A.
2003-10-09
Transformation, which alters the genetic makeup of an individual, is a concept that intrigues the human imagination. In Streptococcus pneumoniae such transformation was first demonstrated. Perhaps our fascination with genetics derived from our ancestors observing their own progeny, with its retention and assortment of parental traits, but such interest must have been accelerated after the dawn of agriculture. It was in pea plants that Gregor Mendel in the late 1800s examined inherited traits and found them to be determined by physical elements, or genes, passed from parents to progeny. In our day, the material basis of these genetic determinants was revealed to be DNA by the lowly bacteria, in particular, the pneumococcus. For this species, transformation by free DNA is a sexual process that enables cells to sport new combinations of genes and traits. Genetic transformation of the type found in S. pneumoniae occurs naturally in many species of bacteria (70), but, initially only a few other transformable species were found, namely, Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrheae, and Bacillus subtilis (96). Natural transformation, which requires a set of genes evolved for the purpose, contrasts with artificial transformation, which is accomplished by shocking cells either electrically, as in electroporation, or by ionic and temperature shifts. Although such artificial treatments can introduce very small amounts of DNA into virtually any type of cell, the amounts introduced by natural transformation are a million-fold greater, and S. pneumoniae can take up as much as 10% of its cellular DNA content (40).
Gauge Theories on the Coulomb Branch
NASA Astrophysics Data System (ADS)
Schwarz, John H.
We construct the world-volume action of a probe D3-brane in AdS5 × S5 with N units of flux. It has the field content, symmetries, and dualities of the U(1) factor of 𝒩 = 4 U(N + 1) super Yang-Mills theory, spontaneously broken to U(N) × U(1) by being on the Coulomb branch, with the massive fields integrated out. This motivates the conjecture that it is the exact effective action, called a highly effective action (HEA). We construct an SL(2, Z) multiplet of BPS soliton solutions of the D3-brane theory (the conjectured HEA) and show that they reproduce the electrically charged massive states that have been integrated out as well as magnetic monopoles and dyons. Their charges are uniformly spread on a spherical surface, called a soliton bubble, which is interpreted as a phase boundary.
A DNase encoded by integrated element CJIE1 inhibits natural transformation of Campylobacter jejuni.
Gaasbeek, Esther J; Wagenaar, Jaap A; Guilhabert, Magalie R; Wösten, Marc M S M; van Putten, Jos P M; van der Graaf-van Bloois, Linda; Parker, Craig T; van der Wal, Fimme J
2009-04-01
The species Campylobacter jejuni is considered naturally competent for DNA uptake and displays strong genetic diversity. Nevertheless, nonnaturally transformable strains and several relatively stable clonal lineages exist. In the present study, the molecular mechanism responsible for the nonnatural transformability of a subset of C. jejuni strains was investigated. Comparative genome hybridization indicated that C. jejuni Mu-like prophage integrated element 1 (CJIE1) was more abundant in nonnaturally transformable C. jejuni strains than in naturally transformable strains. Analysis of CJIE1 indicated the presence of dns (CJE0256), which is annotated as a gene encoding an extracellular DNase. DNase assays using a defined dns mutant and a dns-negative strain expressing Dns from a plasmid indicated that Dns is an endogenous DNase. The DNA-hydrolyzing activity directly correlated with the natural transformability of the knockout mutant and the dns-negative strain expressing Dns from a plasmid. Analysis of a broader set of strains indicated that the majority of nonnaturally transformable strains expressed DNase activity, while all naturally competent strains lacked this activity. The inhibition of natural transformation in C. jejuni via endogenous DNase activity may contribute to the formation of stable lineages in the C. jejuni population.
Daskaloyannis, C. Tanoudis, Y.
2008-05-15
The two-dimensional quantum superintegrable systems with quadratic integrals of motion on a manifold are classified by using the quadratic associative algebra of the integrals of motion. There are six general fundamental classes of quantum superintegrable systems corresponding to the classical ones. Analytic formulas for the involved integrals are calculated in all the cases. All the known quantum superintegrable systems with quadratic integrals are classified as special cases of these six general classes. The coefficients of the quadratic associative algebra of integrals are calculated and they are compared to the coefficients of the corresponding coefficients of the Poisson quadratic algebra of the classical systems. The quantum coefficients are similar to the classical ones multiplied by a quantum coefficient -{h_bar}{sup 2} plus a quantum deformation of order {h_bar}{sup 4} and {h_bar}{sup 6}. The systems inside the classes are transformed using Staeckel transforms in the quantum case as in the classical case. The general form of the Staeckel transform between superintegrable systems is discussed.
Coulomb and nuclear effects in breakup and reaction cross sections
NASA Astrophysics Data System (ADS)
Descouvemont, P.; Canto, L. F.; Hussein, M. S.
2017-01-01
We use a three-body continuum discretized coupled channel (CDCC) model to investigate Coulomb and nuclear effects in breakup and reaction cross sections. The breakup of the projectile is simulated by a finite number of square integrable wave functions. First we show that the scattering matrices can be split in a nuclear term and in a Coulomb term. This decomposition is based on the Lippmann-Schwinger equation and requires the scattering wave functions. We present two different methods to separate both effects. Then, we apply this separation to breakup and reaction cross sections of 7Li+208Pb . For breakup, we investigate various aspects, such as the role of the α +t continuum, the angular-momentum distribution, and the balance between Coulomb and nuclear effects. We show that there is a large ambiguity in defining the Coulomb and nuclear breakup cross sections, since both techniques, although providing the same total breakup cross sections, strongly differ for the individual components. We suggest a third method which could be efficiently used to address convergence problems at large angular momentum. For reaction cross sections, interference effects are smaller, and the nuclear contribution is dominant above the Coulomb barrier. We also draw attention to different definitions of the reaction cross section which exist in the literature and which may induce small, but significant, differences in the numerical values.
Nonstationary multistate Coulomb and multistate exponential models for nonadiabatic transitions
Ostrovsky, V. N.
2003-07-01
The nonstationary Schroedinger equation is considered in a finite basis of states. The model Hamiltonian matrix corresponds to a single diabatic potential curve with a Coulombic {approx}1/t time dependence. An arbitrary number of other diabatic potential curves are flat, i.e., time independent and have arbitrary energies. Related states are coupled by constant interactions with the Coulomb state. The resulting nonstationary Schroedinger equation is solved by the method of contour integral. Probabilities of transitions to any other state are obtained as t{yields}{infinity} in a simple analytical form for the case when the Coulomb state is populated initially (at instant of time t{yields}+0). The formulas apply both to the cases when a horizontal diabatic potential curve is crossed by the Coulomb one and to a noncrossing situation. In the limit of weak coupling, the transition probabilities are interpreted in terms of a sequence of pairwise Landau-Zener-type transitions. Mapping of the Coulomb model onto an exactly solvable exponential multistate model is established. For the special two-state case, the well-known Nikitin model is recovered.
Baker, W.R.
1959-08-25
Transformers of a type adapted for use with extreme high power vacuum tubes where current requirements may be of the order of 2,000 to 200,000 amperes are described. The transformer casing has the form of a re-entrant section being extended through an opening in one end of the cylinder to form a coaxial terminal arrangement. A toroidal multi-turn primary winding is disposed within the casing in coaxial relationship therein. In a second embodiment, means are provided for forming the casing as a multi-turn secondary. The transformer is characterized by minimized resistance heating, minimized external magnetic flux, and an economical construction.
Non-parametric transformation for data correlation and integration: From theory to practice
Datta-Gupta, A.; Xue, Guoping; Lee, Sang Heon
1997-08-01
The purpose of this paper is two-fold. First, we introduce the use of non-parametric transformations for correlating petrophysical data during reservoir characterization. Such transformations are completely data driven and do not require a priori functional relationship between response and predictor variables which is the case with traditional multiple regression. The transformations are very general, computationally efficient and can easily handle mixed data types for example, continuous variables such as porosity, permeability and categorical variables such as rock type, lithofacies. The power of the non-parametric transformation techniques for data correlation has been illustrated through synthetic and field examples. Second, we utilize these transformations to propose a two-stage approach for data integration during heterogeneity characterization. The principal advantages of our approach over traditional cokriging or cosimulation methods are: (1) it does not require a linear relationship between primary and secondary data, (2) it exploits the secondary information to its fullest potential by maximizing the correlation between the primary and secondary data, (3) it can be easily applied to cases where several types of secondary or soft data are involved, and (4) it significantly reduces variance function calculations and thus, greatly facilitates non-Gaussian cosimulation. We demonstrate the data integration procedure using synthetic and field examples. The field example involves estimation of pore-footage distribution using well data and multiple seismic attributes.
Brenna, Andrea; Montanini, Barbara; Muggiano, Eleonora; Proietto, Marco; Filetici, Patrizia; Ottonello, Simone; Ballario, Paola
2014-01-01
Agrobacterium tumefaciens-mediated transformation is a powerful tool for reverse genetics and functional genomic analysis in a wide variety of plants and fungi. Tuber spp. are ecologically important and gastronomically prized fungi ("truffles") with a cryptic life cycle, a subterranean habitat and a symbiotic, but also facultative saprophytic lifestyle. The genome of a representative member of this group of fungi has recently been sequenced. However, because of their poor genetic tractability, including transformation, truffles have so far eluded in-depth functional genomic investigations. Here we report that A. tumefaciens can infect Tuber borchii mycelia, thereby conveying its transfer DNA with the production of stably integrated transformants. We constructed two new binary plasmids (pABr1 and pABr3) and tested them as improved transformation vectors using the green fluorescent protein as reporter gene and hygromycin phosphotransferase as selection marker. Transformants were stable for at least 12 months of in vitro culture propagation and, as revealed by TAIL- PCR analysis, integration sites appear to be heterogeneous, with a preference for repeat element-containing genome sites.
Numerical implementation of the integral-transform solution to Lamb's point-load problem
NASA Astrophysics Data System (ADS)
Georgiadis, H. G.; Vamvatsikos, D.; Vardoulakis, I.
The present work describes a procedure for the numerical evaluation of the classical integral-transform solution of the transient elastodynamic point-load (axisymmetric) Lamb's problem. This solution involves integrals of rapidly oscillatory functions over semi-infinite intervals and inversion of one-sided (time) Laplace transforms. These features introduce difficulties for a numerical treatment and constitute a challenging problem in trying to obtain results for quantities (e.g. displacements) in the interior of the half-space. To deal with the oscillatory integrands, which in addition may take very large values (pseudo-pole behavior) at certain points, we follow the concept of Longman's method but using as accelerator in the summation procedure a modified Epsilon algorithm instead of the standard Euler's transformation. Also, an adaptive procedure using the Gauss 32-point rule is introduced to integrate in the vicinity of the pseudo-pole. The numerical Laplace-transform inversion is based on the robust Fourier-series technique of Dubner/Abate-Crump-Durbin. Extensive results are given for sub-surface displacements, whereas the limit-case results for the surface displacements compare very favorably with previous exact results.
Ontology for Transforming Geo-Spatial Data for Discovery and Integration of Scientific Data
NASA Astrophysics Data System (ADS)
Nguyen, L.; Chee, T.; Minnis, P.
2013-12-01
Discovery and access to geo-spatial scientific data across heterogeneous repositories and multi-discipline datasets can present challenges for scientist. We propose to build a workflow for transforming geo-spatial datasets into semantic environment by using relationships to describe the resource using OWL Web Ontology, RDF, and a proposed geo-spatial vocabulary. We will present methods for transforming traditional scientific dataset, use of a semantic repository, and querying using SPARQL to integrate and access datasets. This unique repository will enable discovery of scientific data by geospatial bound or other criteria.
NASA Astrophysics Data System (ADS)
Elliott, David; Johnston, Peter R.
2007-06-01
In the two-dimensional boundary element method, one often needs to evaluate numerically integrals of the form where j2 is a quadratic, g is a polynomial and f is a rational, logarithmic or algebraic function with a singularity at zero. The constants a and b are such that -1[less-than-or-equals, slant]a[less-than-or-equals, slant]1 and 0integration. In this case the direct application of Gauss-Legendre quadrature can give large truncation errors. By making the transformation x=a+bsinh([mu]u-[eta]), where the constants [mu] and [eta] are chosen so that the interval of integration is again [-1,1], it is found that the truncation errors arising, when the same Gauss-Legendre quadrature is applied to the transformed integral, are much reduced. The asymptotic error analysis for Gauss-Legendre quadrature, as given by Donaldson and Elliott [A unified approach to quadrature rules with asymptotic estimates of their remainders, SIAM J. Numer. Anal. 9 (1972) 573-602], is then used to explain this phenomenon and justify the transformation.
Integrated Personal Health Records: Transformative Tools for Consumer-Centric Care
Detmer, Don; Bloomrosen, Meryl; Raymond, Brian; Tang, Paul
2008-01-01
Background Integrated personal health records (PHRs) offer significant potential to stimulate transformational changes in health care delivery and self-care by patients. In 2006, an invitational roundtable sponsored by Kaiser Permanente Institute, the American Medical Informatics Association, and the Agency for Healthcare Research and Quality was held to identify the transformative potential of PHRs, as well as barriers to realizing this potential and a framework for action to move them closer to the health care mainstream. This paper highlights and builds on the insights shared during the roundtable. Discussion While there is a spectrum of dominant PHR models, (standalone, tethered, integrated), the authors state that only the integrated model has true transformative potential to strengthen consumers' ability to manage their own health care. Integrated PHRs improve the quality, completeness, depth, and accessibility of health information provided by patients; enable facile communication between patients and providers; provide access to health knowledge for patients; ensure portability of medical records and other personal health information; and incorporate auto-population of content. Numerous factors impede widespread adoption of integrated PHRs: obstacles in the health care system/culture; issues of consumer confidence and trust; lack of technical standards for interoperability; lack of HIT infrastructure; the digital divide; uncertain value realization/ROI; and uncertain market demand. Recent efforts have led to progress on standards for integrated PHRs, and government agencies and private companies are offering different models to consumers, but substantial obstacles remain to be addressed. Immediate steps to advance integrated PHRs should include sharing existing knowledge and expanding knowledge about them, building on existing efforts, and continuing dialogue among public and private sector stakeholders. Summary Integrated PHRs promote active, ongoing
Transformation as a Design Process and Runtime Architecture for High Integrity Software
Bespalko, S.J.; Winter, V.L.
1999-04-05
We have discussed two aspects of creating high integrity software that greatly benefit from the availability of transformation technology, which in this case is manifest by the requirement for a sophisticated backtracking parser. First, because of the potential for correctly manipulating programs via small changes, an automated non-procedural transformation system can be a valuable tool for constructing high assurance software. Second, modeling the processing of translating data into information as a, perhaps, context-dependent grammar leads to an efficient, compact implementation. From a practical perspective, the transformation process should begin in the domain language in which a problem is initially expressed. Thus in order for a transformation system to be practical it must be flexible with respect to domain-specific languages. We have argued that transformation applied to specification results in a highly reliable system. We also attempted to briefly demonstrate that transformation technology applied to the runtime environment will result in a safe and secure system. We thus believe that the sophisticated multi-lookahead backtracking parsing technology is central to the task of being in a position to demonstrate the existence of HIS.
Ordering in classical Coulombic systems.
Schiffer, J. P.
1998-01-22
The author discusses the properties of classical Coulombic matter at low temperatures. It has been well known for some time [1,2] that infinite Coulombic matter will crystallize in body-centered cubic form when the quantity {Lambda} (the dimensionless ratio of the average two-particle Coulomb energy to the kinetic energy per particle) is larger than {approximately}175. But the systems of such particles that have been produced in the laboratory in ion traps, or ion beams, are finite with surfaces defined by the boundary conditions that have to be satisfied. This results in ion clouds with sharply defined curved surfaces, and interior structures that show up as a set of concentric layers that are parallel to the outer surface. The ordering does not appear to be cubic, but the charges on each shell exhibit a ''hexatic'' pattern of equilateral triangles that is the characteristic of liquid crystals. The curvature of the surfaces prevents the structures on successive shells from interlocking in any simple fashion. This class of structures was first found in simulations [3] and later in experiments [4].
NASA Astrophysics Data System (ADS)
Shen, Fabin; Wang, Anbo
2006-02-01
The numerical calculation of the Rayleigh-Sommerfeld diffraction integral is investigated. The implementation of a fast-Fourier-transform (FFT) based direct integration (FFT-DI) method is presented, and Simpson's rule is used to improve the calculation accuracy. The sampling interval, the size of the computation window, and their influence on numerical accuracy and on computational complexity are discussed for the FFT-DI and the FFT-based angular spectrum (FFT-AS) methods. The performance of the FFT-DI method is verified by numerical simulation and compared with that of the FFT-AS method.
Local-instantaneous filtering in the integral transform solution of nonlinear diffusion problems
NASA Astrophysics Data System (ADS)
Macêdo, E. N.; Cotta, R. M.; Orlande, H. R. B.
A novel filtering strategy is proposed to be utilized in conjunction with the Generalized Integral Transform Technique (GITT), in the solution of nonlinear diffusion problems. The aim is to optimize convergence enhancement, yielding computationally efficient eigenfunction expansions. The proposed filters include space and time dependence, extracted from linearized versions of the original partial differential system. The scheme automatically updates the filter along the time integration march, as the required truncation orders for the user requested accuracy begin to exceed a prescribed maximum system size. A fully nonlinear heat conduction example is selected to illustrate the computational performance of the filtering strategy, against the classical single-filter solution behavior.
Zhao, Guoliang; Li, Hongxing
2013-01-01
This paper proposes new methodologies for the design of adaptive integral-sliding mode control. A tensor product model transformation based adaptive integral-sliding mode control law with respect to uncertainties and perturbations is studied, while upper bounds on the perturbations and uncertainties are assumed to be unknown. The advantage of proposed controllers consists in having a dynamical adaptive control gain to establish a sliding mode right at the beginning of the process. Gain dynamics ensure a reasonable adaptive gain with respect to the uncertainties. Finally, efficacy of the proposed controller is verified by simulations on an uncertain nonlinear system model. PMID:24453897
Kiyokura, Takanori; Ito, Takahiro; Sawada, Renshi
2004-12-01
This paper describes a Fourier transform (FT) near-infrared spectrometer that uses an integrated prism scanning interferometer whose optical paths are stabilized by corner cubes. A combination of corner cubes and a retroreflection mirror, which is sometimes used in the conventional interferometer for FT spectrometers, is adopted and adapted to the integrated prism scanning interferometer through a special design. Without any degradation of spectroscopic properties, the optical path in the interferometer is highly stabilized and the moving distance of the stage is halved. These advantages provide a robust and portable FT spectrometer for field use.
Zhao, Guoliang; Sun, Kaibiao; Li, Hongxing
2013-01-01
This paper proposes new methodologies for the design of adaptive integral-sliding mode control. A tensor product model transformation based adaptive integral-sliding mode control law with respect to uncertainties and perturbations is studied, while upper bounds on the perturbations and uncertainties are assumed to be unknown. The advantage of proposed controllers consists in having a dynamical adaptive control gain to establish a sliding mode right at the beginning of the process. Gain dynamics ensure a reasonable adaptive gain with respect to the uncertainties. Finally, efficacy of the proposed controller is verified by simulations on an uncertain nonlinear system model.
ERIC Educational Resources Information Center
Grimm, C. A.
This document contains two units that examine integral transforms and series expansions. In the first module, the user is expected to learn how to use the unified method presented to obtain Laplace transforms, Fourier transforms, complex Fourier series, real Fourier series, and half-range sine series for given piecewise continuous functions. In…
PREFACE: Strongly Coupled Coulomb Systems Strongly Coupled Coulomb Systems
NASA Astrophysics Data System (ADS)
Neilson, David; Senatore, Gaetano
2009-05-01
This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS), held from 29 July-2 August 2008 at the University of Camerino. Camerino is an ancient hill-top town located in the Apennine mountains of Italy, 200 kilometres northeast of Rome, with a university dating back to 1336. The Camerino conference was the 11th in a series which started in 1977: 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (hosted by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (hosted by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, New York, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) 2005: Moscow, Russia (hosted by Vladimir E Fortov and Vladimir Vorob'ev). The name of the series was changed in 1996 from Strongly Coupled Plasmas to Strongly Coupled Coulomb Systems to reflect a wider range of topics. 'Strongly Coupled Coulomb Systems' encompasses diverse many-body systems and physical conditions. The purpose of the conferences is to provide a regular international forum for the presentation and discussion of research achievements and ideas relating to a variety of plasma, liquid and condensed matter systems that are dominated by strong Coulomb interactions between their constituents. Each meeting has seen an evolution of topics and emphases that have followed new discoveries and new techniques. The field has continued to see new experimental tools and access to new strongly coupled conditions, most recently in the areas of warm matter, dusty plasmas
Efficient local statistical analysis via integral histograms with discrete wavelet transform.
Lee, Teng-Yok; Shen, Han-Wei
2013-12-01
Histograms computed from local regions are commonly used in many visualization applications, and allowing the user to query histograms interactively in regions of arbitrary locations and sizes plays an important role in feature identification and tracking. Computing histograms in regions with arbitrary location and size, nevertheless, can be time consuming for large data sets since it involves expensive I/O and scan of data elements. To achieve both performance- and storage-efficient query of local histograms, we present a new algorithm called WaveletSAT, which utilizes integral histograms, an extension of the summed area tables (SAT), and discrete wavelet transform (DWT). Similar to SAT, an integral histogram is the histogram computed from the area between each grid point and the grid origin, which can be be pre-computed to support fast query. Nevertheless, because one histogram contains multiple bins, it will be very expensive to store one integral histogram at each grid point. To reduce the storage cost for large integral histograms, WaveletSAT treats the integral histograms of all grid points as multiple SATs, each of which can be converted into a sparse representation via DWT, allowing the reconstruction of axis-aligned region histograms of arbitrary sizes from a limited number of wavelet coefficients. Besides, we present an efficient wavelet transform algorithm for SATs that can operate on each grid point separately in logarithmic time complexity, which can be extended to parallel GPU-based implementation. With theoretical and empirical demonstration, we show that WaveletSAT can achieve fast preprocessing and smaller storage overhead than the conventional integral histogram approach with close query performance.
Elastic Coulomb breakup of 34Na
NASA Astrophysics Data System (ADS)
Singh, G.; Shubhchintak, Chatterjee, R.
2016-08-01
Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our
van Peer, Arend F.; de Bekker, Charissa; Vinck, Arman; Wösten, Han A. B.; Lugones, Luis G.
2009-01-01
Phleomycin is mutagenic by introducing double-strand breaks in DNA. The ble gene of Streptoalloteychus hindustanus, which confers resistance to this substance, is widely used as a selection marker for transformation. Schizophyllum commune grows on 25 μg of phleomycin ml−1 after introduction of a resistance cassette based on the ble gene. However, we here report that growth of resistant colonies on this concentration of phleomycin resulted in aberrant colony morphologies. Apparently, phleomycin was mutagenic despite acquired resistance. Therefore, a new selection system was developed based on resistance to the antibiotic nourseothricin. However, the transformation efficiency was tenfold lower than that obtained with phleomycin as a selection agent. This low transformation efficiency could be rescued by addition of a nonselective concentration of phleomycin during protoplast regeneration. This was accompanied by a higher incidence of single-copy integrations and with an increase of expression of key genes involved in double-strand break repair. Taken together, we conclude that the effect of a nonselective concentration of phleomycin strongly resembles the effect of restriction enzyme-mediated integration (REMI) but, unlike REMI, it does not depend on the presence of a target restriction site. PMID:19114524
Newman, S. M.; Boynton, J. E.; Gillham, N. W.; Randolph-Anderson, B. L.; Johnson, A. M.; Harris, E. H.
1990-01-01
Transformation of chloroplast ribosomal RNA (rRNA) genes in Chlamydomonas has been achieved by the biolistic process using cloned chloroplast DNA fragments carrying mutations that confer antibiotic resistance. The sites of exchange employed during the integration of the donor DNA into the recipient genome have been localized using a combination of antibiotic resistance mutations in the 16S and 23S rRNA genes and restriction fragment length polymorphisms that flank these genes. Complete or nearly complete replacement of a region of the chloroplast genome in the recipient cell by the corresponding sequence from the donor plasmid was the most common integration event. Exchange events between the homologous donor and recipient sequences occurred preferentially near the vector:insert junctions. Insertion of the donor rRNA genes and flanking sequences into one inverted repeat of the recipient genome was followed by intramolecular copy correction so that both copies of the inverted repeat acquired identical sequences. Increased frequencies of rRNA gene transformants were achieved by reducing the copy number of the chloroplast genome in the recipient cells and by decreasing the heterology between donor and recipient DNA sequences flanking the selectable markers. In addition to producing bona fide chloroplast rRNA transformants, the biolistic process induced mutants resistant to low levels of streptomycin, typical of nuclear mutations in Chlamydomonas. PMID:1981764
Self-Consistent Sources for Integrable Equations Via Deformations of Binary Darboux Transformations
NASA Astrophysics Data System (ADS)
Chvartatskyi, Oleksandr; Dimakis, Aristophanes; Müller-Hoissen, Folkert
2016-08-01
We reveal the origin and structure of self-consistent source extensions of integrable equations from the perspective of binary Darboux transformations. They arise via a deformation of the potential that is central in this method. As examples, we obtain in particular matrix versions of self-consistent source extensions of the KdV, Boussinesq, sine-Gordon, nonlinear Schrödinger, KP, Davey-Stewartson, two-dimensional Toda lattice and discrete KP equation. We also recover a (2+1)-dimensional version of the Yajima-Oikawa system from a deformation of the pKP hierarchy. By construction, these systems are accompanied by a hetero binary Darboux transformation, which generates solutions of such a system from a solution of the source-free system and additionally solutions of an associated linear system and its adjoint. The essence of all this is encoded in universal equations in the framework of bidifferential calculus.
Integrated system for image storage, retrieval, and transmission using wavelet transform
NASA Astrophysics Data System (ADS)
Yu, Dan; Liu, Yawen; Mu, Ray Y.; Yang, Shi-Qiang
1998-12-01
Currently, much work has been done in the area of image storage and retrieval. However, the overall performance has been far from practical. A highly integrated wavelet-based image management system is proposed in this paper. By integrating wavelet-based solutions for image compression and decompression, content-based retrieval and progressive transmission, much higher performance can be achieved. The multiresolution nature of the wavelet transform has been proven to be a powerful tool to represent images. The wavelet transform decomposes the image into a set of subimages with different resolutions. From here three solutions for key aspects of image management are reached. The content-based image retrieval (CBIR) features of our system include the color, contour, texture, sample, keyword and topic information of images. The first four features can be naturally extracted from the wavelet transform coefficients. By scoring the similarity of users' requests with images in the database, those who have higher scores are noted and the user receives feedback. Image compression and decompression. Assuming that details at high resolution and diagonal directions are less visible to the human eye, a good compression ratio can be achieved. In each subimage, the wavelet coefficients are vector quantized (VQ), using the LGB algorithm, which is improved in our approach to accelerate the process. Higher compression ratio can be achieved with DPCM and entropy coding method applied together. With YIQ representation, color images can also be effectively compressed. There is a very low load on the network bandwidth by transmitting compressed image data across the network. Progressive transmission is possible by employment of the multiresolution nature of the wavelet, which makes the system respond faster and the user-interface more friendly. The system shows a high overall performance by exploring the excellent features of wavelet, and integrating key aspects of image management. An
Nguyen, Thach G; Shoeiby, Mehrdad; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J
2015-08-24
We demonstrate a photonic RF Hilbert transformer for broadband microwave in-phase and quadrature-phase generation based on an integrated frequency optical comb, generated using a nonlinear microring resonator based on a CMOS compatible, high-index contrast, doped-silica glass platform. The high quality and large frequency spacing of the comb enables filters with up to 20 taps, allowing us to demonstrate a quadrature filter with more than a 5-octave (3 dB) bandwidth and an almost uniform phase response.
NASA Astrophysics Data System (ADS)
Denisenko, M. V.; Munyaev, V. O.; Satanin, A. M.
2016-11-01
The parametric frequency division in a coplanar waveguide line with an integrated single-contact rf SQUID (Josephson oscillator) is discussed. It is assumed that the oscillator is excited by pump pulses whose carrier frequency can be a multiple of the plasma frequency of the oscillator. It is shown that the Josephson oscillator excited at the pump frequency can induce frequency division by emitting subharmonics that are multiples of the fundamental frequency (fractional resonances). Parameters for which parametric frequency transformation occurs are determined. The possible generalization of this effect to the quantum case in which correlated microwave photons (entangled photon states) can be generated is discussed.
PREFACE: Strongly Coupled Coulomb Systems
NASA Astrophysics Data System (ADS)
Fortov, Vladimir E.; Golden, Kenneth I.; Norman, Genri E.
2006-04-01
This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS) which was held during the week of 20 24 June 2005 in Moscow, Russia. The Moscow conference was the tenth in a series of conferences. The previous conferences were organized as follows. 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (organized by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (organized by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, NY, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) After 1995 the name of the series was changed from `Strongly Coupled Plasmas' to the present name in order to extend the topics of the conferences. The planned frequency for the future is once every three years. The purpose of these conferences is to provide an international forum for the presentation and discussion of research accomplishments and ideas relating to a variety of plasma liquid and condensed matter systems, dominated by strong Coulomb interactions between their constituents. Strongly coupled Coulomb systems encompass diverse many-body systems and physical conditions. Each meeting has seen an evolution of topics and emphasis as new discoveries and new methods appear. This year, sessions were organized for invited presentations and posters on dense plasmas and warm matter, astrophysics and dense hydrogen, non-neutral and ultracold plasmas, dusty plasmas, condensed matter 2D and layered charged-particle systems, Coulomb liquids, and statistical theory of SCCS. Within
Analytical expressions for partial wave two-body Coulomb transition matrices at ground-state energy
NASA Astrophysics Data System (ADS)
Kharchenko, V. F.
2016-11-01
Leaning upon the Fock method of the stereographic projection of the three-dimensional momentum space onto the four-dimensional unit sphere the possibility of the analytical solving of the Lippmann-Schwinger integral equation for the partial wave two-body Coulomb transition matrix at the ground bound state energy has been studied. In this case new expressions for the partial p-, d- and f-wave two-body Coulomb transition matrices have been obtained in the simple analytical form. The developed approach can also be extended to determine analytically the partial wave Coulomb transition matrices at the energies of excited bound states.
Coulomb-nuclear interference in 56 MeV deuteron breakup at extreme forward angle
NASA Astrophysics Data System (ADS)
Samanta, C.; Kanungo, Rituparna; Mukherjee, Sanjukta; Basu, D. N.
1995-02-01
Recently measured 12C(d,pn) 12C breakup data show a dip in the energy integrated cross section below a momentum transfer ∼ 117 MeV/ c. We analyse these data by the prior form distorted-wave Born approximation theory. Although the double humped structure of the θp = θn = 0° data exhibit the dominance of Coulomb-breakup, the pronounced asymmetry of the energy sharing data cannot be explained through Coulomb breakup only. A closer agreement to the data is obtained through Coulomb-nuclear interference and an unusual optical potential of longer range in the exit channel.
The Effects of Static Coulomb Stress Change on Southern California Earthquake Forecasts
NASA Astrophysics Data System (ADS)
Strader, A. E.; Jackson, D. D.
2013-12-01
In previous studies, we confirmed an association between static Coulomb stress change and earthquake location in southern California, when resolving stress tensors onto uniformly oriented northwest right-lateral strike-slip planes (Deng & Sykes, 1997). Using an optimized index function to convert static Coulomb stress change into normalized seismicity rates, we found that the Coulomb stress-based forecasts were not significantly more effective indicators of future earthquake locations than forecasts based on smoothed seismicity (Hiemer et al., 2011). These results were likely due to Coulomb stress uncertainties, particularly near stress singularities at the ends of fault sections where many earthquakes occurred. We evaluate hybrid Coulomb stress/smoothed seismicity earthquake forecasts against those with earthquake rates derived from only one component, within a southern California study area (32°N-37°N latitude, 122°W-114°W longitude). Using a weighted linear combination of earthquake rates derived from static Coulomb stress change and smoothed seismicity, we mitigate the effects of stress uncertainty through increasing the influence of Coulomb stress on earthquake rates with increasing distance from faults. We also evaluate time-dependent Coulomb stress earthquake forecasts based on rate-and-state friction (Toda & Enescu, 2011 and Dieterich, 1996) against a Poissonian null hypothesis, from the 10/16/1999 Hector Mine earthquake to the 4/4/2010 El Mayor Cucapah earthquake. From numerical integration, we establish a normalized seismicity rate for each day, during the target time interval, from Coulomb stress evolution and the times since all preceding source earthquakes. During each day we assume seismicity follows a Poissonian process, with expected rates defined as the rate-and-state seismicity rates. By pseudo-prospectively testing these spatial and spatiotemporal earthquake forecasts, we ascertain the role of static and quasi-static Coulomb stress change in
Coulombic contribution and fat center vortex model
Rafibakhsh, Shahnoosh; Deldar, Sedigheh
2007-02-27
The fat (thick) center vortex model is one of the phenomenological models which is fairly successful to interpret the linear potential between static sources. However, the Coulombic part of the potential has not been investigated by the model yet. In an attempt to get the Coulombic contribution and to remove the concavity of the potentials, we are studying different vortex profiles and vortex sizes.
Matharu, Zimple; Patel, Dipali; Gao, Yandong; Haque, Amranul; Zhou, Qing; Revzin, Alexander
2014-09-02
We developed a cell-culture/biosensor platform consisting of aptamer-modified Au electrodes integrated with reconfigurable microfluidics for monitoring of transforming growth factor-beta 1 (TGF-β1), an important inflammatory and pro-fibrotic cytokine. Aptamers were thiolated, labeled with redox reporters, and self-assembled on gold surfaces. The biosensor was determined to be specific for TGF-β1 with an experimental detection limit of 1 ng/mL and linear range extending to 250 ng/mL. Upon determining figures of merit, aptasensor was miniaturized and integrated with human hepatic stellate cells inside microfluidic devices. Reconfigurable microfluidics were developed to ensure that seeding of "sticky" stromal cells did not foul the electrode and compromise sensor performance. This microsystem with integrated aptasensors was used to monitor TGF-β1 release from activated stellate cells over the course of 20 h. The electrochemical response went down upon infusing anti-TGF-β1 antibodies into the microfluidic devices containing activated stellate cells. To further validate aptasensor responses, stellate cells were stained for markers of activation (e.g., alpha smooth muscle actin) and were also tested for presence of TGF-β1 using enzyme linked immunosorbent assay (ELISA). Given the importance of TGF-β1 as a fibrogenic signal, a microsystem with integrated biosensors for local and continuous detection of TGF-β1 may prove to be an important tool to study fibrosis of the liver and other organs.
NASA Astrophysics Data System (ADS)
Gao, Yingjie; Zhang, Jinhai; Yao, Zhenxing
2016-06-01
The symplectic integration method is popular in high-accuracy numerical simulations when discretizing temporal derivatives; however, it still suffers from time-dispersion error when the temporal interval is coarse, especially for long-term simulations and large-scale models. We employ the inverse time dispersion transform (ITDT) to the third-order symplectic integration method to reduce the time-dispersion error. First, we adopt the pseudospectral algorithm for the spatial discretization and the third-order symplectic integration method for the temporal discretization. Then, we apply the ITDT to eliminate time-dispersion error from the synthetic data. As a post-processing method, the ITDT can be easily cascaded in traditional numerical simulations. We implement the ITDT in one typical exiting third-order symplectic scheme and compare its performances with the performances of the conventional second-order scheme and the rapid expansion method. Theoretical analyses and numerical experiments show that the ITDT can significantly reduce the time-dispersion error, especially for long travel times. The implementation of the ITDT requires some additional computations on correcting the time-dispersion error, but it allows us to use the maximum temporal interval under stability conditions; thus, its final computational efficiency would be higher than that of the traditional symplectic integration method for long-term simulations. With the aid of the ITDT, we can obtain much more accurate simulation results but with a lower computational cost.
TRANSVERSE MERCATOR MAP PROJECTION OF THE SPHEROID USING TRANSFORMATION OF THE ELLIPTIC INTEGRAL
NASA Technical Reports Server (NTRS)
Wallis, D. E.
1994-01-01
the (irreducible) Incomplete Elliptic Integral of the 2nd Kind, the value for the tangent of one half the amplitude of the Elliptic Integral of the 2nd Kind is now known. The elliptic integral may now be computed by any desired method, and the result will be the Gauss-Kruger Transverse Mercator Projection. This result is a consequence of the fact that these steps produce a computation of real distance along the image (in the plane) of the principal meridian, and an analytic continuation of the distance at points that don't lie on the principal meridian. The elliptic-integral method used by this program is one of the "transformations of the elliptic integral" (similar to Landen's Transformation), appearing in standard handbooks of mathematical functions. Only elementary transcendental functions are utilized. The program output is the conventional (as used by the mapping agencies) cartesian coordinates, in meters, of the Transverse Mercator projection. The origin is at the intersection of the principal meridian and the equator. This FORTRAN77 program was developed on an IBM PC series computer equipped with an Intel Math Coprocessor. Double precision complex arithmetic and transcendental functions are needed to support a projection accuracy of 1 mm. Because such functions are not usually part of the FORTRAN library, the needed functions have been explicitly programmed and included in the source code. The program was developed in 1989. TRANSVERSE MERCATOR MAP PROJECTION OF THE SPHEROID USING TRANSFORMATIONS OF THE ELLIPTIC INTEGRAL is a copyrighted work with all copyright vested in NASA.
NASA Astrophysics Data System (ADS)
Liu, Chongxuan; Szecsody, Jim E.; Zachara, John M.; Ball, William P.
The generalized integral transform technique (GITT) is applied to solve the one-dimensional advection-dispersion equation (ADE) in heterogeneous porous media coupled with either linear or nonlinear sorption and decay. When both sorption and decay are linear, analytical solutions are obtained using the GITT for one-dimensional ADEs with spatially and temporally variable flow and dispersion coefficient and arbitrary initial and boundary conditions. When either sorption or decay is nonlinear the solutions to ADEs with the GITT are hybrid analytical-numerical. In both linear and nonlinear cases, the forward and inverse integral transforms for the problems described in the paper are apparent and straightforward. Some illustrative examples with linear sorption and decay are presented to demonstrate the application and check the accuracy of the derived analytical solutions. The derived hybrid analytical-numerical solutions are checked against a numerical approach and demonstratively applied to a nonlinear transport example, which simulates a simplified system of iron oxide bioreduction with nonlinear sorption and nonlinear reaction kinetics.
Flow integration transform: detecting shapes in matrix-array 3D ultrasound data
NASA Astrophysics Data System (ADS)
Stetten, George D.; Caines, Michael; von Ramm, Olaf T.
1995-03-01
Matrix-array ultrasound produces real-time 3D images of the heart, by employing a square array of transducers to steer the ultrasound beam in three dimensions electronically with no moving parts. Other 3D modalities such as MR, MUGA, and CT require the use of gated studies, which combine many cardiac cycles to produce a single average cycle. Three- dimensional ultrasound eliminates this restriction, in theory permitting the continuous measurement of cardiac ventricular volume, which we call the volumetricardiogram. Towards implementing the volumetricardiogram, we have developed the flow integration transform (FIT), which operates on a 2D slice within the volumetric ultrasound data. The 3D ultrasound machine's scan converter produces a set of such slices in real time, at any desired location and orientation, to which the FIT may then be applied. Although lacking rotational or scale invariance, the FIT is designed to operate in dedicated hardware where an entire transform could be completed within a few microseconds with present integrated circuit technology. This speed would permit the application of a large battery of test shapes, or the evolution of the test shape to converge on that of the actual target.
Zhang, Min; Jiang, Shaotong; Zheng, Juan; Zheng, Zhi; Li, Xingjiang; Pan, Lijun; Luo, Shuizhong
2015-08-01
To construct a system of genetic transformation suitable for Rhizopus oryzae, we constructed a single-exchange vector pBS-hygro carrying hygromycin B resistance gene (hph) as its selective marker using gene splicing by overlap extension PCR (SOE PCR) technique. We introduced this recombinant vector into Rhizopus oryzae AS 3.819 by PEG/CaCl2-mediated transformation of protoplast, electroporation of protoplast and germinated spores; and we studied the effects of hydrolysis time, field strength and spore germination time on transformation frequency. We conducted quantitative real-time PCR (qPCR) assay to determine the gene copy number of ldhA integrated in the genome of R. oryzae transformants and its effect on the stability of transformants. We successfully achieved R. oryzae transformants integrated with pBS-hygro-ldhA vector. The optimal hydrolysis time for protoplast production was 140 min, and the optimal field strength of electroporation pulse for protoplast was 13 kV/cm. The optimal germination time of spores for electroporation was 2.5 h, and the optimal field strength of electroporation pulse was 14 kV/cm. The transformation frequency of method based on germinated spores was generally higher than the methods based on protoplast. The qPCR test results suggested that transformants with high copy number of integration in a certain range were relatively stable. Our results provided basis and support for metabolic regulation and genetic engineering breeding of R. oryzae.
NASA Technical Reports Server (NTRS)
Pawloski, Janice S.
2001-01-01
This project uses the integral transform technique to model the problem of nanotube behavior as an axially symmetric system of shells. Assuming that the nanotube behavior can be described by the equations of elasticity, we seek a stress function x which satisfies the biharmonic equation: del(exp 4) chi = [partial deriv(r(exp 2)) + partial deriv(r) + partial deriv(z(exp 2))] chi = 0. The method of integral transformations is used to transform the differential equation. The symmetry with respect to the z-axis indicates that we only need to consider the sine transform of the stress function: X(bar)(r,zeta) = integral(from 0 to infinity) chi(r,z)sin(zeta,z) dz.
The Coulombic Lattice Potential of Ionic Compounds: The Cubic Perovskites.
ERIC Educational Resources Information Center
Francisco, E.; And Others
1988-01-01
Presents coulombic models representing the particles of a system by point charges interacting through Coulomb's law to explain coulombic lattice potential. Uses rubidium manganese trifluoride as an example of cubic perovskite structure. Discusses the effects on cluster properties. (CW)
Al Khawaja, U.
2010-05-15
We derive the integrability conditions of nonautonomous nonlinear Schroedinger equations using the Lax pair and similarity transformation methods. We present a comparative analysis of these integrability conditions with those of the Painleve method. We show that while the Painleve integrability conditions restrict the dispersion, nonlinearity, and dissipation/gain coefficients to be space independent and the external potential to be only a quadratic function of position, the Lax Pair and the similarity transformation methods allow for space-dependent coefficients and an external potential that is not restricted to the quadratic form. The integrability conditions of the Painleve method are retrieved as a special case of our general integrability conditions. We also derive the integrability conditions of nonautonomous nonlinear Schroedinger equations for two- and three-spacial dimensions.
Dynamical Coulomb blockade of tunnel junctions driven by alternating voltages
NASA Astrophysics Data System (ADS)
Grabert, Hermann
2015-12-01
The theory of the dynamical Coulomb blockade is extended to tunneling elements driven by a time-dependent voltage. It is shown that, for standard setups where an external voltage is applied to a tunnel junction via an impedance, time-dependent driving entails an excitation of the modes of the electromagnetic environment by the applied voltage. Previous approaches for ac driven circuits need to be extended to account for the driven bath modes. A unitary transformation involving also the variables of the electromagnetic environment is introduced which allows us to split off the time dependence from the Hamiltonian in the absence of tunneling. This greatly simplifies perturbation-theoretical calculations based on treating the tunneling Hamiltonian as a perturbation. In particular, the average current flowing in the leads of the tunnel junction is studied. Explicit results are given for the case of an applied voltage with a constant dc part and a sinusoidal ac part. The connection with standard dynamical Coulomb blockade theory for constant applied voltage is established. It is shown that an alternating voltage source reveals significant additional effects caused by the electromagnetic environment. The hallmark of the dynamical Coulomb blockade in ac driven devices is a suppression of higher harmonics of the current by the electromagnetic environment. The theory presented basically applies to all tunneling devices driven by alternating voltages.
Correlation functions of Coulomb branch operators
NASA Astrophysics Data System (ADS)
Gerchkovitz, Efrat; Gomis, Jaume; Ishtiaque, Nafiz; Karasik, Avner; Komargodski, Zohar; Pufu, Silviu S.
2017-01-01
We consider the correlation functions of Coulomb branch operators in four-dimensional N = 2 Superconformal Field Theories (SCFTs) involving exactly one antichiral operator. These extremal correlators are the "minimal" non-holomorphic local observables in the theory. We show that they can be expressed in terms of certain determinants of derivatives of the four-sphere partition function of an appropriate deformation of the SCFT. This relation between the extremal correlators and the deformed four-sphere partition function is non-trivial due to the presence of conformal anomalies, which lead to operator mixing on the sphere. Evaluating the deformed four-sphere partition function using supersymmetric localization, we compute the extremal correlators explicitly in many interesting examples. Additionally, the representation of the extremal correlators mentioned above leads to a system of integrable differential equations. We compare our exact results with previous perturbative computations and with the four-dimensional tt ∗ equations. We also use our results to study some of the asymptotic properties of the perturbative series expansions we obtain in N = 2 SQCD.
A new method to calculate the beam charge for an integrating current transformer
Wu Yuchi; Han Dan; Zhu Bin; Dong Kegong; Tan Fang; Gu Yuqiu
2012-09-15
The integrating current transformer (ICT) is a magnetic sensor widely used to precisely measure the charge of an ultra-short-pulse charged particle beam generated by traditional accelerators and new laser-plasma particle accelerators. In this paper, we present a new method to calculate the beam charge in an ICT based on circuit analysis. The output transfer function shows an invariable signal profile for an ultra-short electron bunch, so the function can be used to evaluate the signal quality and calculate the beam charge through signal fitting. We obtain a set of parameters in the output function from a standard signal generated by an ultra-short electron bunch (about 1 ps in duration) at a radio frequency linear electron accelerator at Tsinghua University. These parameters can be used to obtain the beam charge by signal fitting with excellent accuracy.
Simulation of the superconducting multiturn flux transformer integrated with a coplanar resonator
NASA Astrophysics Data System (ADS)
Yi, H. R.; Zhang, Y.; Klein, N.
2000-06-01
The analysis of the structure of a superconducting multiturn flux transformer integrated with a coplanar resonator for radio-frequency superconducting quantum interference devices is described. Electromagnetic simulations indicate that the loss is dominated by the high loss tangent of the dielectric film used for the separation of the upper and lower superconducting films. The simulated current distribution at its resonant frequency shows that the highest current density is distributed on the multiturn input coil. This current distribution leads to a very high loss when the loss tangent of the dielectric film is high. However, for the same loss tangent of the dielectric film, it is possible to get a reasonably high unloaded quality factor by providing a normal shunt for the multiturn input coil.
Geometric BVPs, Hardy spaces, and the Cauchy integral and transform on regions with corners
NASA Astrophysics Data System (ADS)
Loya, Paul
In this paper we give a new perspective on the Cauchy integral and transform and Hardy spaces for Dirac-type operators on manifolds with corners of codimension two. Instead of considering Banach or Hilbert spaces, we use polyhomogeneous functions on a geometrically "blown-up" version of the manifold called the total boundary blow-up introduced by Mazzeo and Melrose [R.R. Mazzeo, R.B. Melrose, Analytic surgery and the eta invariant, Geom. Funct. Anal. 5 (1) (1995) 14-75]. These polyhomogeneous functions are smooth everywhere on the original manifold except at the corners where they have a "Taylor series" (with possible log terms) in polar coordinates. The main application of our analysis is a complete Fredholm theory for boundary value problems of Dirac operators on manifolds with corners of codimension two.
NASA Astrophysics Data System (ADS)
Engel, Megan C.; Ritchie, Dustin B.; Foster, Daniel A. N.; Beach, Kevin S. D.; Woodside, Michael T.
2014-12-01
The energy landscapes that drive structure formation in biopolymers are difficult to measure. Here we validate experimentally a novel method to reconstruct landscape profiles from single-molecule pulling curves using an inverse Weierstrass transform (IWT) of the Jarzysnki free-energy integral. The method was applied to unfolding measurements of a DNA hairpin, replicating the results found by the more-established weighted histogram (WHAM) and inverse Boltzmann methods. Applying both WHAM and IWT methods to reconstruct the folding landscape for a RNA pseudoknot having a stiff energy barrier, we found that landscape features with sharper curvature than the force probe stiffness could not be recovered with the IWT method. The IWT method is thus best for analyzing data from stiff force probes such as atomic force microscopes.
NASA Technical Reports Server (NTRS)
Verber, C. M.; Vahey, D. W.; Wood, V. E.; Kenan, R. P.; Hartman, N. F.
1977-01-01
The possibility of producing an integrated optics data processing device based upon Fourier transformations or other parallel processing techniques, and the ways in which such techniques may be used to upgrade the performance of present and projected NASA systems were investigated. Activities toward this goal include; (1) production of near-diffraction-limited geodesic lenses in glass waveguides; (2) development of grinding and polishing techniques for the production of geodesic lenses in LiNbO3 waveguides; (3) development of a characterization technique for waveguide lenses; and (4) development of a theory for corrected aspheric geodesic lenses. A holographic subtraction system was devised which should be capable of rapid on-board preprocessing of a large number of parallel data channels. The principle involved is validated in three demonstrations.
Fedele, L A; Even, J; Garon, C F; Donner, L; Sherr, C J
1981-01-01
The integrated DNA provirus of the Gardner-Arnstein (GA) strain of feline sarcoma virus (FeSV) was molecularly cloned in a bacteriophage lambda vector. The cloned DNA fragment is 14.4 kilobase pairs long and contains a 6.7-kilobase provirus flanked by cellular sequences derived from nonproductively transformed mink cells. Transfection of mouse NIH/3T3 cells with the cloned DNA fragment induced foci of transformation at efficiencies of 10(4) focus-forming units/pmol of sarcoma virus DNA. Restriction endonuclease mapping and heteroduplex analyses were used to compare the GA-FeSV provirus with that of Snyder-Theilen (ST)-FeSV, a second strain that contains homologous transformation-specific sequences (v-fes). Both viruses have the general structure 5'-gag-fes-env-c region-3', each having retained portions of the feline leukemia virus (FeLV) gag and env genes. In addition to segments shared by the two sarcoma viruses, GA-FeSV contains 1.7 kilobases of extra sequences not found in ST-FeSV. Of these, at least 400-500 base pairs located near the 5' end of v-fes encode a portion of the GA-FeSV polyprotein; the remaining 1.2 kilobases are derived from the FeLV env gene but do not appear to encode any detectable product related to the FeLV envelope glycoprotein. The close homology of the v-fes sequences shows that GA- and ST-FeSV were formed by recombination of FeLV with similar portions of a cat cellular gene (c-fes). Images PMID:6270655
Hait, Subrata; Tare, Vinod
2012-05-01
Transformation and availability of nutrients and some heavy metals were assessed during the integrated composting-vermicomposting of both primary sewage sludge (PSS) and waste activated sewage sludge (WAS) using matured vermicompost as indigenous bulking material and employing Eisenia fetida as earthworm species. Vermicomposting resulted in significant increase in total N (TN) (PSS: 41.7-64.6%, F=11.6, P<0.05; WAS: 36.4-58.6%, F=6.4, P<0.05), water soluble N (WSN) (PSS: 37.1-50.5%, F=30.1, P<0.05; WAS: 40.1-53.0%, F=27.6, P<0.05), total P (TP) (PSS: 39.9-69.8%, F=27.1, P<0.05; WAS: 32.2-56.6%, F=21.4, P<0.05) and water soluble P (WSP) (PSS: 25.2-34.3%, F=163.9, P<0.05; WAS: 24.1-34.2%, F=144.3, P<0.05) as compared to the initial compost material depending on different experimental conditions. The study demonstrated that the vermicomposting significantly improved the availability of nutrients in sewage sludges. In addition, vermicomposting considerably reduced the availability of heavy metals except Fe and Mn, presumably by forming organic-bound complexes in spite of several fold increase in their total content. The environmental conditions (i.e., temperature and relative humidity), in general, showed significant effect on the transformation and availability of nutrients and heavy metals. There was no effect of earthworm density on the transformation and availability of heavy metals and nutrients except N and P, possibly due to prior exposure during acclimation period in sewage sludge.
Three New (2+1)-dimensional Integrable Systems and Some Related Darboux Transformations
NASA Astrophysics Data System (ADS)
Guo, Xiu-Rong
2016-06-01
We introduce two operator commutators by using different-degree loop algebras of the Lie algebra A1, then under the framework of zero curvature equations we generate two (2+1)-dimensional integrable hierarchies, including the (2+1)-dimensional shallow water wave (SWW) hierarchy and the (2+1)-dimensional Kaup-Newell (KN) hierarchy. Through reduction of the (2+1)-dimensional hierarchies, we get a (2+1)-dimensional SWW equation and a (2+1)-dimensional KN equation. Furthermore, we obtain two Darboux transformations of the (2+1)-dimensional SWW equation. Similarly, the Darboux transformations of the (2+1)-dimensional KN equation could be deduced. Finally, with the help of the spatial spectral matrix of SWW hierarchy, we generate a (2+1) heat equation and a (2+1) nonlinear generalized SWW system containing inverse operators with respect to the variables x and y by using a reduction spectral problem from the self-dual Yang-Mills equations. Supported by the National Natural Science Foundation of China under Grant No. 11371361, the Shandong Provincial Natural Science Foundation of China under Grant Nos. ZR2012AQ011, ZR2013AL016, ZR2015EM042, National Social Science Foundation of China under Grant No. 13BJY026, the Development of Science and Technology Project under Grant No. 2015NS1048 and A Project of Shandong Province Higher Educational Science and Technology Program under Grant No. J14LI58
NASA Astrophysics Data System (ADS)
Rossbach, P. C.
1985-12-01
The calculation of the Discrete Fourier Transform has long been a significant bottleneck in many Digital Signal Processing applications. With the arrival of Very Large Scale Integration and new DFT algorithms, system architectures that significantly reduce the DFT bottleneck are possible. This thesis addresses the design, simulation, implementation, and testing of the control circuitry for a high speed, VLSI Winograd Fourier Transform (WFT) processor. Three WFT processors are combined into a pipelined architecture that is capable of computing a 4080-point DFT on complex input data approximately every 120 microseconds when operating with 70 MHz clock signals. The chip control architecture features a special Programmable Logic Array (PLA) to control the on-chip arithmetic circuitry, and a dense, 54K ROM to generate data addresses for the external RAM. The PLA controller was fabricated in 3 micron CMOS and functioned properly for clock rates of over 60 MHz. The address generator ROM was designed and submitted for fabrication in 3 micron CMOS, and SPICE simulations predict an access time of 60 nanoseconds. Software that automatically generates a ROM layout description from a data file was developed to ensure the correctness of the final design. The transistor minimization procedure i s based on a graph partitioning heuristic, and the drain removal procedure is based on an algorithm that near-optimally solves the Traveling Salesman Problem.
Crystallization in two-component Coulomb systems.
Bonitz, M; Filinov, V S; Fortov, V E; Levashov, P R; Fehske, H
2005-12-02
The analysis of Coulomb crystallization is extended from one-component to two-component plasmas. Critical parameters for the existence of Coulomb crystals are derived for both classical and quantum crystals. In the latter case, a critical mass ratio of the two charged components is found, which is of the order of 80. Thus, holes in semiconductors with sufficiently flat valence bands are predicted to spontaneously order into a regular lattice. Such hole crystals are intimately related to ion Coulomb crystals in white dwarf and neutron stars as well as to ion crystals produced in the laboratory. A unified phase diagram of two-component Coulomb crystals is presented and is verified by first-principles computer simulations.
Wakunuma, Kutoma; Rainey, Stephen; Hansen, Christian
2017-01-01
Research on Brain Computer Interfaces (BCI) often aims to provide solutions for vulnerable populations, such as individuals with diseases, conditions or disabilities that keep them from using traditional interfaces. Such research thereby contributes to the public good. This contribution to the public good corresponds to a broader drive of research and funding policy that focuses on promoting beneficial societal impact. One way of achieving this is to engage with the public. In practical terms this can be done by integrating civil society organisations (CSOs) in research. The open question at the heart of this paper is whether and how such CSO integration can transform the research and contribute to the public good. To answer this question the paper describes five detailed qualitative case studies of research projects including CSOs. The paper finds that transformative impact of CSO integration is possible but by no means assured. It provides recommendations on how transformative impact can be promoted. PMID:28207882
Stahl, Bernd Carsten; Wakunuma, Kutoma; Rainey, Stephen; Hansen, Christian
2017-01-01
Research on Brain Computer Interfaces (BCI) often aims to provide solutions for vulnerable populations, such as individuals with diseases, conditions or disabilities that keep them from using traditional interfaces. Such research thereby contributes to the public good. This contribution to the public good corresponds to a broader drive of research and funding policy that focuses on promoting beneficial societal impact. One way of achieving this is to engage with the public. In practical terms this can be done by integrating civil society organisations (CSOs) in research. The open question at the heart of this paper is whether and how such CSO integration can transform the research and contribute to the public good. To answer this question the paper describes five detailed qualitative case studies of research projects including CSOs. The paper finds that transformative impact of CSO integration is possible but by no means assured. It provides recommendations on how transformative impact can be promoted.
Recent developments in Coulomb breakup calculations
Capel, P.
2008-05-12
The theory of reactions applied to Coulomb breakup of loosely-bound projectiles is reviewed. Both the Continuum Discretized Coupled Channel (CDCC) and time-dependent models are described. Recent results about sensitivity of breakup calculations to the projectile wave function are reviewed. Analyses of the extraction of radiative-capture cross section from Coulomb breakup measurements are presented. Current developments in breakup theory are also mentioned.
Coulomb crystal mass spectrometry in a digital ion trap
NASA Astrophysics Data System (ADS)
Deb, Nabanita; Pollum, Laura L.; Smith, Alexander D.; Keller, Matthias; Rennick, Christopher J.; Heazlewood, Brianna R.; Softley, Timothy P.
2015-03-01
We present a mass spectrometric technique for identifying the masses and relative abundances of Coulomb-crystallized ions held in a linear Paul trap. A digital radio-frequency wave form is employed to generate the trapping potential, as this can be cleanly switched off, and static dipolar fields are subsequently applied to the trap electrodes for ion ejection. Close to 100% detection efficiency is demonstrated for Ca+ and CaF+ ions from bicomponent Ca+-CaF+ Coulomb crystals prepared by the reaction of Ca+ with CH3F . A quantitative linear relationship is observed between ion number and the corresponding integrated time-of-flight (TOF) peak, independent of the ionic species. The technique is applicable to a diverse range of multicomponent Coulomb crystals—demonstrated here for Ca+-NH 3+ -NH 4+ and Ca+-CaOH +-CaOD + crystals—and will facilitate the measurement of ion-molecule reaction rates and branching ratios in complicated reaction systems.
The algebra of the quantum nondegenerate three-dimensional Kepler-Coulomb potential
Tanoudis, Y.; Daskaloyannis, C.
2011-07-15
The classical generalized Kepler-Coulomb potential, introduced by Verrier and Evans, corresponds to a quantum superintegrable system, with quadratic and quartic integrals of motion. In this paper we show that the algebra of the integrals is a quadratic ternary algebra, i.e a quadratic extension of a Lie triple system.
Slave rotor approach to dynamically screened Coulomb interactions in solids
NASA Astrophysics Data System (ADS)
Krivenko, I. S.; Biermann, S.
2015-04-01
Recent studies of dynamical screening of the electronic Coulomb interactions in solids have revived interest in lattice models of correlated fermions coupled to bosonic degrees of freedom (Hubbard-Holstein-type models). We propose a new dynamical mean-field-based approach to dynamically screened Coulomb interactions. In the effective Anderson-Holstein model, a transformation to slave rotors [S. Florens and A. Georges, Phys. Rev. B 66, 165111 (2002), 10.1103/PhysRevB.66.165111] is performed to decouple the dynamical part of the interaction. This transformation allows for a systematic derivation and analysis of recently introduced approximate schemes for the solution of dynamical impurity problems, in particular, the Bose factor ansatz within the dynamic atomic limit approximation (DALA) with and without Lang-Firsov correction. More importantly still, it suggests an optimized choice for a Bose factor in the sense of the variational principle of Feynman and Peierls. We demonstrate the accuracy of our scheme and present a comparison to calculations within the DALA.
Bates, Jason H T; Sobel, Burton E
2003-05-01
This is the third in a series of four articles developed for the readers of Coronary Artery Disease. Without language ideas cannot be articulated. What may not be so immediately obvious is that they cannot be formulated either. One of the essential languages of cardiology is mathematics. Unfortunately, medical education does not emphasize, and in fact, often neglects empowering physicians to think mathematically. Reference to statistics, conditional probability, multicompartmental modeling, algebra, calculus and transforms is common but often without provision of genuine conceptual understanding. At the University of Vermont College of Medicine, Professor Bates developed a course designed to address these deficiencies. The course covered mathematical principles pertinent to clinical cardiovascular and pulmonary medicine and research. It focused on fundamental concepts to facilitate formulation and grasp of ideas.This series of four articles was developed to make the material available for a wider audience. The articles will be published sequentially in Coronary Artery Disease. Beginning with fundamental axioms and basic algebraic manipulations they address algebra, function and graph theory, real and complex numbers, calculus and differential equations, mathematical modeling, linear system theory and integral transforms and statistical theory. The principles and concepts they address provide the foundation needed for in-depth study of any of these topics. Perhaps of even more importance, they should empower cardiologists and cardiovascular researchers to utilize the language of mathematics in assessing the phenomena of immediate pertinence to diagnosis, pathophysiology and therapeutics. The presentations are interposed with queries (by Coronary Artery Disease abbreviated as CAD) simulating the nature of interactions that occurred during the course itself. Each article concludes with one or more examples illustrating application of the concepts covered to
Bae, Sunwoong; Park, Seunghye; Kim, Jung; Choi, Jong Seob; Kim, Kyung Hoon; Kwon, Donguk; Jin, EonSeon; Park, Inkyu; Kim, Do Hyun; Seo, Tae Seok
2015-12-16
Superior green algal cells showing high lipid production and rapid growth rate are considered as an alternative for the next generation green energy resources. To achieve the biomass based energy generation, transformed microalgae with superlative properties should be developed through genetic engineering. Contrary to the normal cells, microalgae have rigid cell walls, so that target gene delivery into cells is challengeable. In this study, we report a ZnO nanowire-incorporated microdevice for a high throughput microalgal transformation. The proposed microdevice was equipped with not only a ZnO nanowire in the microchannel for gene delivery into cells but also a pneumatic polydimethylsiloxane (PDMS) microvalve to modulate the cellular attachment and detachment from the nanowire. As a model, hygromycin B resistance gene cassette (Hyg3) was functionalized on the hydrothermally grown ZnO nanowires through a disulfide bond and released into green algal cells, Chlamydomonas reinhardtii, by reductive cleavage. During Hyg3 gene delivery, a monolithic PDMS membrane was bent down, so that algal cells were pushed down toward ZnO nanowires. The supply of vacuum in the pneumatic line made the PDMS membrane bend up, enabling the gene delivered algal cells to be recovered from the outlet of the microchannel. We successfully confirmed Hyg3 gene integrated in microalgae by amplifying the inserted gene through polymerase chain reaction (PCR) and DNA sequencing. The efficiency of the gene delivery to algal cells using the ZnO nanowire-incorporated microdevice was 6.52 × 10(4)- and 9.66 × 10(4)-fold higher than that of a traditional glass bead beating and electroporation.
Strong-field ionization via a high-order Coulomb-corrected strong-field approximation
NASA Astrophysics Data System (ADS)
Klaiber, Michael; Daněk, Jiří; Yakaboylu, Enderalp; Hatsagortsyan, Karen Z.; Keitel, Christoph H.
2017-02-01
Signatures of the Coulomb corrections in the photoelectron momentum distribution during laser-induced ionization of atoms or ions in tunneling and multiphoton regimes are investigated analytically in the case of a one-dimensional problem. A high-order Coulomb-corrected strong-field approximation is applied, where the exact continuum state in the S matrix is approximated by the eikonal Coulomb-Volkov state including the second-order corrections to the eikonal. Although without high-order corrections our theory coincides with the known analytical R -matrix (ARM) theory, we propose a simplified procedure for the matrix element derivation. Rather than matching the eikonal Coulomb-Volkov wave function with the bound state as in the ARM theory to remove the Coulomb singularity, we calculate the matrix element via the saddle-point integration method by time as well as by coordinate, and in this way avoiding the Coulomb singularity. The momentum shift in the photoelectron momentum distribution with respect to the ARM theory due to high-order corrections is analyzed for tunneling and multiphoton regimes. The relation of the quantum corrections to the tunneling delay time is discussed.
The distinguishable cluster approach from a screened Coulomb formalism.
Kats, Daniel
2016-01-28
The distinguishable cluster doubles equations have been derived starting from an effective screened Coulomb formalism and a particle-hole symmetric formulation of the Fock matrix. A perturbative triples correction to the distinguishable cluster with singles and doubles (DCSD) has been introduced employing the screened integrals. It is shown that the resulting DCSD(T) method is more accurate than DCSD for reaction energies and is less sensitive to the static correlation than coupled cluster with singles and doubles with a perturbative triples correction.
Analytical approach to quasiperiodic beam Coulomb field modeling
NASA Astrophysics Data System (ADS)
Rubtsova, I. D.
2016-09-01
The paper is devoted to modeling of space charge field of quasiperiodic axial- symmetric beam. Particle beam is simulated by charged disks. Two analytical Coulomb field expressions are presented, namely, Fourier-Bessel series and trigonometric polynomial. Both expressions permit the integral representation. It provides the possibility of integro-differential beam dynamics description. Consequently, when beam dynamics optimization problem is considered, it is possible to derive the analytical formula for quality functional gradient and to apply directed optimization methods. In addition, the paper presents the method of testing of space charge simulation code.
Ice limit of Coulomb gauge Yang-Mills theory
Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; McMullan, D.
2008-10-01
In this paper we describe gauge invariant multiquark states generalizing the path integral framework developed by Parrinello, Jona-Lasinio, and Zwanziger to amend the Faddeev-Popov approach. This allows us to produce states such that, in a limit which we call the ice limit, fermions are dressed with glue exclusively from the fundamental modular region associated with Coulomb gauge. The limit can be taken analytically without difficulties, avoiding the Gribov problem. This is illustrated by an unambiguous construction of gauge invariant mesonic states for which we simulate the static quark-antiquark potential.
Emissions of ammonia and methane from an anaerobic lagoon at a swine animal feeding operation were evaluated five times over a period of two years. The plane-integrated (PI) open-path Fourier transform infrared spectrometry (OP-FTIR) methodology was used to transect the plume at ...
ERIC Educational Resources Information Center
Kingston, Mary; Richards, Curtis; Blank, Rolf; Stonemeier, Jennifer; Trader, Barbara; East, Bill
2014-01-01
In this Issue Brief we discuss the impact that the Schoolwide Integrated Framework for Transformation (SWIFT) has on improving the outcomes of several current federal, state, district, and school education reform initiatives. Federal initiatives include Race to the Top, School Improvement Grants, and Campaign for Grade-Level Reading; Common Core…
Some results on the integral transforms and applications to differential equations
Eltayeb, Hassan; Kilicman, Adem
2010-11-11
In this paper we give some remark about the relationship between Sumudu and Laplace transforms, further; for the comparison purpose, we apply both transforms to solve partial differential equations to see the differences and similarities.
Marshall, Deborah A; Burgos-Liz, Lina; Pasupathy, Kalyan S; Padula, William V; IJzerman, Maarten J; Wong, Peter K; Higashi, Mitchell K; Engbers, Jordan; Wiebe, Samuel; Crown, William; Osgood, Nathaniel D
2016-02-01
In the era of the Information Age and personalized medicine, healthcare delivery systems need to be efficient and patient-centred. The health system must be responsive to individual patient choices and preferences about their care, while considering the system consequences. While dynamic simulation modelling (DSM) and big data share characteristics, they present distinct and complementary value in healthcare. Big data and DSM are synergistic-big data offer support to enhance the application of dynamic models, but DSM also can greatly enhance the value conferred by big data. Big data can inform patient-centred care with its high velocity, volume, and variety (the three Vs) over traditional data analytics; however, big data are not sufficient to extract meaningful insights to inform approaches to improve healthcare delivery. DSM can serve as a natural bridge between the wealth of evidence offered by big data and informed decision making as a means of faster, deeper, more consistent learning from that evidence. We discuss the synergies between big data and DSM, practical considerations and challenges, and how integrating big data and DSM can be useful to decision makers to address complex, systemic health economics and outcomes questions and to transform healthcare delivery.
Peeraer, Jef; Van Petegem, Peter
2015-02-01
Over the last two decades, crucial factors for Information and Communication Technology (ICT) in education have improved significantly in Vietnam. Nevertheless, it is clear that, as in other countries, no educational revolution is taking place. We argue that there is a need for a broad dialogue on the future of ICT in education in Vietnam as discussion of ideas about future possibilities can be instrumental in rationalizing and generating educational change. We explore how a group of key players representing the public and private sector as well as development partners in the field look at the future of ICT in education in the country. Following the Delphi method, these key players assessed in different survey rounds the current situation of ICT in education, identified a series of targets and were asked to assess these targets in respect of their importance. The key players reached a consensus that the purpose of technology integration is to achieve learning goals and enhance learning. However, there is more controversy on targets that could potentially transform education practice in Vietnam. We discuss the value of the Delphi technique and argue for increased participation of all involved stakeholders in policy development on ICT in education.
Coulomb wave functions in momentum space
Eremenko, V.; Upadhyay, N. J.; Thompson, I. J.; ...
2015-10-15
We present an algorithm to calculate non-relativistic partial-wave Coulomb functions in momentum space. The arguments are the Sommerfeld parameter η, the angular momentum l, the asymptotic momentum q and the 'running' momentum p, where both momenta are real. Since the partial-wave Coulomb functions exhibit singular behavior when p → q, different representations of the Legendre functions of the 2nd kind need to be implemented in computing the functions for the values of p close to the singularity and far away from it. The code for the momentum-space Coulomb wave functions is applicable for values of vertical bar eta vertical barmore » in the range of 10-1 to 10, and thus is particularly suited for momentum space calculations of nuclear reactions.« less
Coulomb wave functions in momentum space
Eremenko, V.; Upadhyay, N. J.; Thompson, I. J.; Elster, Ch.; Nunes, F. M.; Arbanas, G.; Escher, J. E.; Hlophe, L.
2015-10-15
We present an algorithm to calculate non-relativistic partial-wave Coulomb functions in momentum space. The arguments are the Sommerfeld parameter η, the angular momentum l, the asymptotic momentum q and the 'running' momentum p, where both momenta are real. Since the partial-wave Coulomb functions exhibit singular behavior when p → q, different representations of the Legendre functions of the 2nd kind need to be implemented in computing the functions for the values of p close to the singularity and far away from it. The code for the momentum-space Coulomb wave functions is applicable for values of vertical bar eta vertical bar in the range of 10^{-1} to 10, and thus is particularly suited for momentum space calculations of nuclear reactions.
Approximate Coulomb distortion effects in (e,e{sup {prime}}p) reactions
Kim, K.S.; Wright, L.E.
1997-07-01
In this paper we apply a well-tested approximation of electron Coulomb distortion effects to the exclusive reaction (e,e{sup {prime}}p) in the quasielastic region. We compare the approximate treatment of Coulomb distortion effects to the exact distorted wave Born approximation evaluated by means of partial wave analysis to gauge the quality of our approximate treatment. We show that the approximate Mo/ller potential has a plane-wave-like structure and hence permits the separation of the cross section into five terms which depend on bilinear products of transforms of the transition four current elements. These transforms reduce to Fourier transforms when Coulomb distortion is not present, but become modified with the inclusion of Coulomb distortion. We investigate the application of the approximate formalism to a model of {sup 208}Pb(e,e{sup {prime}}p) using Dirac-Hartree single particle wave functions for the ground state and relativistic optical model wave functions for the continuum proton. We show that it is still possible to extract, albeit with some approximation, the various structure functions from the experimentally measured data even for heavy nuclei. {copyright} {ital 1997} {ital The American Physical Society}
Observation of ionic Coulomb blockade in nanopores
NASA Astrophysics Data System (ADS)
Feng, Jiandong; Liu, Ke; Graf, Michael; Dumcenco, Dumitru; Kis, Andras; di Ventra, Massimiliano; Radenovic, Aleksandra
2016-08-01
Emergent behaviour from electron-transport properties is routinely observed in systems with dimensions approaching the nanoscale. However, analogous mesoscopic behaviour resulting from ionic transport has so far not been observed, most probably because of bottlenecks in the controlled fabrication of subnanometre nanopores for use in nanofluidics. Here, we report measurements of ionic transport through a single subnanometre pore junction, and the observation of ionic Coulomb blockade: the ionic counterpart of the electronic Coulomb blockade observed for quantum dots. Our findings demonstrate that nanoscopic, atomically thin pores allow for the exploration of phenomena in ionic transport, and suggest that nanopores may also further our understanding of transport through biological ion channels.
Three-body Coulomb continuum problem
NASA Astrophysics Data System (ADS)
Berakdar, J.; Briggs, J. S.
1994-06-01
A symmetric representation of the three-body Coulomb continuum wave function as a product of three two-body Coulomb wave functions is modified to allow for three-body effects whereby the Sommerfeld parameter describing the strength of interaction of any two particles is affected by the presence of the third particle. This approach gives excellent agreement with near-threshold absolute (e,2e) ionization cross sections. In particular a recently observed deep minimum in noncoplanar geometry is reproduced for the first time.
An implicit fast Fourier transform method for integration of the time dependent Schrodinger equation
Riley, M.E.; Ritchie, A.B.
1997-12-31
One finds that the conventional exponentiated split operator procedure is subject to difficulties when solving the time-dependent Schrodinger equation for Coulombic systems. By rearranging the kinetic and potential energy terms in the temporal propagator of the finite difference equations, one can find a propagation algorithm for three dimensions that looks much like the Crank-Nicholson and alternating direction implicit methods for one- and two-space-dimensional partial differential equations. The authors report investigations of this novel implicit split operator procedure. The results look promising for a purely numerical approach to certain electron quantum mechanical problems. A charge exchange calculation is presented as an example of the power of the method.
Repair-dependent cell radiation survival and transformation: an integrated theory.
Sutherland, John C
2014-09-07
The repair-dependent model of cell radiation survival is extended to include radiation-induced transformations. The probability of transformation is presumed to scale with the number of potentially lethal damages that are repaired in a surviving cell or the interactions of such damages. The theory predicts that at doses corresponding to high survival, the transformation frequency is the sum of simple polynomial functions of dose; linear, quadratic, etc, essentially as described in widely used linear-quadratic expressions. At high doses, corresponding to low survival, the ratio of transformed to surviving cells asymptotically approaches an upper limit. The low dose fundamental- and high dose plateau domains are separated by a downwardly concave transition region. Published transformation data for mammalian cells show the high-dose plateaus predicted by the repair-dependent model for both ultraviolet and ionizing radiation. For the neoplastic transformation experiments that were analyzed, the data can be fit with only the repair-dependent quadratic function. At low doses, the transformation frequency is strictly quadratic, but becomes sigmodial over a wider range of doses. Inclusion of data from the transition region in a traditional linear-quadratic analysis of neoplastic transformation frequency data can exaggerate the magnitude of, or create the appearance of, a linear component. Quantitative analysis of survival and transformation data shows good agreement for ultraviolet radiation; the shapes of the transformation components can be predicted from survival data. For ionizing radiations, both neutrons and x-rays, survival data overestimate the transforming ability for low to moderate doses. The presumed cause of this difference is that, unlike UV photons, a single x-ray or neutron may generate more than one lethal damage in a cell, so the distribution of such damages in the population is not accurately described by Poisson statistics. However, the complete
Coulomb string tension, asymptotic string tension, and the gluon chain
Greensite, Jeff; Szczepaniak, Adam P.
2015-02-01
We compute, via numerical simulations, the non-perturbative Coulomb potential and position-space ghost propagator in pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.
A Coulomb-Like Off-Shell T-Matrix with the Correct Coulomb Phase Shift
NASA Astrophysics Data System (ADS)
Oryu, Shinsho; Watanabe, Takashi; Hiratsuka, Yasuhisa; Togawa, Yoshio
2017-03-01
We confirm the reliability of the well-known Coulomb renormalization method (CRM). It is found that the CRM is only available for a very-long-range screened Coulomb potential (SCP). However, such an SCP calculation in momentum space is considerably difficult because of the cancelation of significant digits. In contrast to the CRM, we propose a new method by using an on-shell equivalent SCP and the rest term. The two-potential theory with r-space is introduced, which defines fully the off-shell Coulomb amplitude.
NASA Astrophysics Data System (ADS)
Šprlák, Michal; Novák, Pavel
2017-02-01
New spherical integral formulas between components of the second- and third-order gravitational tensors are formulated in this article. First, we review the nomenclature and basic properties of the second- and third-order gravitational tensors. Initial points of mathematical derivations, i.e., the second- and third-order differential operators defined in the spherical local North-oriented reference frame and the analytical solutions of the gradiometric boundary-value problem, are also summarized. Secondly, we apply the third-order differential operators to the analytical solutions of the gradiometric boundary-value problem which gives 30 new integral formulas transforming (1) vertical-vertical, (2) vertical-horizontal and (3) horizontal-horizontal second-order gravitational tensor components onto their third-order counterparts. Using spherical polar coordinates related sub-integral kernels can efficiently be decomposed into azimuthal and isotropic parts. Both spectral and closed forms of the isotropic kernels are provided and their limits are investigated. Thirdly, numerical experiments are performed to test the consistency of the new integral transforms and to investigate properties of the sub-integral kernels. The new mathematical apparatus is valid for any harmonic potential field and may be exploited, e.g., when gravitational/magnetic second- and third-order tensor components become available in the future. The new integral formulas also extend the well-known Meissl diagram and enrich the theoretical apparatus of geodesy.
Benchmark values for molecular three-center integrals arising in the Dirac equation
NASA Astrophysics Data System (ADS)
Baǧcı, A.; Hoggan, P. E.
2015-10-01
Previous papers by the authors report that they obtained compact, arbitrarily accurate expressions for two-center, one- and two-electron relativistic molecular integrals expressed over Slater-type orbitals. In the present study, accuracy limits of expressions given are examined for three-center nuclear attraction integrals, which are one-electron, three-center integrals with no analytically closed-form expression. In this work new molecular auxiliary functions are used. They are obtained via Neumann expansion of the Coulomb interaction. The numerical global adaptive method is used to evaluate these integrals for arbitrary values of orbital parameters and quantum numbers. Several methods, such as Laplace expansion of Coulomb interaction, single-center expansion, and the Fourier transformation method, have previously been used to evaluate these integrals considering the values of principal quantum numbers in the set of positive integer numbers. This study of three-center integrals places no restrictions on quantum numbers in all ranges of orbital parameters.
Benchmark values for molecular three-center integrals arising in the Dirac equation.
Bağcı, A; Hoggan, P E
2015-10-01
Previous papers by the authors report that they obtained compact, arbitrarily accurate expressions for two-center, one- and two-electron relativistic molecular integrals expressed over Slater-type orbitals. In the present study, accuracy limits of expressions given are examined for three-center nuclear attraction integrals, which are one-electron, three-center integrals with no analytically closed-form expression. In this work new molecular auxiliary functions are used. They are obtained via Neumann expansion of the Coulomb interaction. The numerical global adaptive method is used to evaluate these integrals for arbitrary values of orbital parameters and quantum numbers. Several methods, such as Laplace expansion of Coulomb interaction, single-center expansion, and the Fourier transformation method, have previously been used to evaluate these integrals considering the values of principal quantum numbers in the set of positive integer numbers. This study of three-center integrals places no restrictions on quantum numbers in all ranges of orbital parameters.
Coulomb drag between helical Luttinger liquids
NASA Astrophysics Data System (ADS)
Kainaris, N.; Gornyi, I. V.; Levchenko, A.; Polyakov, D. G.
2017-01-01
We theoretically study Coulomb drag between two helical edges with broken spin-rotational symmetry, such as would occur in two capacitively coupled quantum spin Hall insulators. For the helical edges, Coulomb drag is particularly interesting because it specifically probes the inelastic interactions that break the conductance quantization for a single edge. Using the kinetic equation formalism, supplemented by bosonization, we find that the drag resistivity ρD exhibits a nonmonotonic dependence on the temperature T . In the limit of low T ,ρD vanishes with decreasing T as a power law if intraedge interactions are not too strong. This is in stark contrast to Coulomb drag in conventional quantum wires, where ρD diverges at T →0 irrespective of the strength of repulsive interactions. Another unusual property of Coulomb drag between the helical edges concerns higher T for which, unlike in the Luttinger liquid model, drag is mediated by plasmons. The special type of plasmon-mediated drag can be viewed as a distinguishing feature of the helical liquid—because it requires peculiar umklapp scattering only available in the presence of a Dirac point in the electron spectrum.
Coulomb Logarithm, Version 1.0
Singleton, Robert
2016-11-23
Clog is a library of charged particle stopping powers and related Coulomb logarithm processes in a plasma. The stopping power is a particularly useful quantity for plasma physics, as it measures the energy loss of per unit length of charged particle as it traverses a plasma. Clog's primary stopping power is the BPS (Brown-Preston-Singleton) theory.
Technology Transfer Automated Retrieval System (TEKTRAN)
The species Campylobacter jejuni displays huge genetic diversity, and is naturally competent for DNA uptake. Nevertheless, not every strain is able to acquire foreign DNA since nonnaturally transformable strains do exist. Previously we showed that many nonnaturally transformable C. jejuni strains ex...
NASA Astrophysics Data System (ADS)
Marikhin, V. G.
2016-12-01
We construct a three-dimensional octahedral lattice of Bäcklund transformations of integrable cases of the Davey-Stewartson system. At the lattice sites, we arrange functions, which, on one hand, are used to define the dynamical variables of the Davey-Stewartson system and, on the other hand, are connected by bilinear relations of the Hirota type. One of the lattice equations is a purely discrete six-point equation that coincides with the famous Hirota equation.
NASA Astrophysics Data System (ADS)
Liu, Hanze; Xin, Xiangpeng; Wang, Zenggui; Liu, Xiqiang
2017-03-01
This paper is concerned with the Bäcklund transformations (BTs) of the nonlinear evolution equations (NLEEs). Based on the homogeneous balance principle (HBP), the existence of the BT of the generalized Burgers'-KdV (B-KdV) equation is classified, then the BTs of the nonlinear equations are given. In general, the method can be used to construct BTs of the nonlinear evolution equations in polynomial form. Furthermore, the integrability and exact explicit solutions to the nonlinear equations are investigated.
Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots
NASA Astrophysics Data System (ADS)
Keller, A. J.; Lim, J. S.; Sánchez, David; López, Rosa; Amasha, S.; Katine, J. A.; Shtrikman, Hadas; Goldhaber-Gordon, D.
2016-08-01
In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior.
Quantum mechanics on phase space and the Coulomb potential
NASA Astrophysics Data System (ADS)
Campos, P.; Martins, M. G. R.; Vianna, J. D. M.
2017-04-01
Symplectic quantum mechanics (SMQ) makes possible to derive the Wigner function without the use of the Liouville-von Neumann equation. In this formulation of the quantum theory the Galilei Lie algebra is constructed using the Weyl (or star) product with Q ˆ = q ⋆ = q +iħ/2∂p , P ˆ = p ⋆ = p -iħ/2∂q, and the Schrödinger equation is rewritten in phase space; in consequence physical applications involving the Coulomb potential present some specific difficulties. Within this context, in order to treat the Schrödinger equation in phase space, a procedure based on the Levi-Civita (or Bohlin) transformation is presented and applied to two-dimensional (2D) hydrogen atom. Amplitudes of probability in phase space and the correspondent Wigner quasi-distribution functions are derived and discussed.
Measurement of the 92,93,94,100Mo(γ,n) reactions by Coulomb Dissociation
NASA Astrophysics Data System (ADS)
Göbel, K.; Adrich, P.; Altstadt, S.; Alvarez-Pol, H.; Aksouh, F.; Aumann, T.; Babilon, M.; Behr, K.-H.; Benlliure, J.; Berg, T.; Böhmer, M.; Boretzky, K.; Brünle, A.; Beyer, R.; Casarejos, E.; Chartier, M.; Cortina-Gil, D.; Chatillon, A.; Datta Pramanik, U.; Deveaux, L.; Elvers, M.; Elze, T. W.; Emling, H.; Erhard, M.; Ershova; Fernandez-Dominguez, B.; Geissel, H.; Górska, M.; Heftrich, T.; Heil, M.; Hellstroem, M.; Ickert, G.; Johansson, H.; Junghans, A. R.; Käppeler, F.; Kiselev, O.; Klimkiewicz, A.; Kratz, J. V.; Kulessa, R.; Kurz, N.; Labiche, M.; Langer, C.; Le Bleis, T.; Lemmon, R.; Lindenberg, K.; Litvinov, Y. A.; Maierbeck, P.; Movsesyan, A.; Müller, S.; Nilsson, T.; Nociforo, C.; Paar, N.; Palit, R.; Paschalis, S.; Plag, R.; Prokopowicz, W.; Reifarth, R.; Rossi, D. M.; Schnorrenberger, L.; Simon, H.; Sonnabend, K.; Sümmerer, K.; Surówka, G.; Vretenar, D.; Wagner, A.; Walter, S.; Waluś, W.; Wamers, F.; Weick, H.; Weigand, M.; Winckler, N.; Winkler, M.; Zilges, A.
2016-01-01
The Coulomb Dissociation (CD) cross sections of the stable isotopes 92,94,100Mo and of the unstable isotope 93Mo were measured at the LAND/R3B setup at GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. Experimental data on these isotopes may help to explain the problem of the underproduction of 92,94Mo and 96,98Ru in the models of p-process nucleosynthesis. The CD cross sections obtained for the stable Mo isotopes are in good agreement with experiments performed with real photons, thus validating the method of Coulomb Dissociation. The result for the reaction 93Mo(γ,n) is especially important since the corresponding cross section has not been measured before. A preliminary integral Coulomb Dissociation cross section of the 94Mo(γ,n) reaction is presented. Further analysis will complete the experimental database for the (γ,n) production chain of the p-isotopes of molybdenum.
DNA Integrity and Shock Wave Transformation Efficiency of Bacteria and Fungi
NASA Astrophysics Data System (ADS)
Loske, Achim M.; Campos-Guillén, Juan; Fernández, Francisco; Pastrana, Xóchitl; Magaña-Ortíz, Denis; Coconi-Linares, Nancy; Ortíz-Vázquez, Elizabeth; Gómez-Lim, Miguel
Delivery of DNA into bacteria and fungi is essential in medicine and biotechnology to produce metabolites, enzymes, antibiotics and proteins. So far, protocols to genetically transform bacteria and fungi are inefficient and have low reproducibility.
Absence of exponential clustering in quantum Coulomb fluids
NASA Astrophysics Data System (ADS)
Alastuey, A.; Martin, Ph. A.
1989-12-01
We show that the quantum corrections to the classical correlations of a Coulomb fluid do not decay exponentially fast for all values of the thermodynamical parameters. Specifically, the ħ4 term in the Wigner-Kirkwood expansion of the equilibrium charge-charge correlations of the quantum one-component plasma is found to decay like ||r||-10. More generally, using functional integration, we present a diagrammatic representation of the ħ expansion of the correlations in a multicomponent fluid with a locally regularized Coulomb potential and Maxwell-Boltzmann statistics. The ħ2n terms are found to decay algebraically for all n>=2. Furthermore, an analysis of the hierarchy equations for the correlations provides upper bounds that are compatible with the findings of the perturbative expansion. Except for the monopole, all higher-order multipole sum rules do not hold, in general, in the quantum system. This violation of the multipole sum rules as well as the related algebraic tails are due to the intrinsic quantum fluctuations that prevent a perfect organization of the screening clouds. This phenomenon is illustrated in a simpler model where the large-distance correlations between two quantum particles embedded in a classical plasma can be exactly computed.
Coulomb Bound States of Strongly Interacting Photons
NASA Astrophysics Data System (ADS)
Maghrebi, M. F.; Gullans, M. J.; Bienias, P.; Choi, S.; Martin, I.; Firstenberg, O.; Lukin, M. D.; Büchler, H. P.; Gorshkov, A. V.
2015-09-01
We show that two photons coupled to Rydberg states via electromagnetically induced transparency can interact via an effective Coulomb potential. This interaction gives rise to a continuum of two-body bound states. Within the continuum, metastable bound states are distinguished in analogy with quasibound states tunneling through a potential barrier. We find multiple branches of metastable bound states whose energy spectrum is governed by the Coulomb potential, thus obtaining a photonic analogue of the hydrogen atom. Under certain conditions, the wave function resembles that of a diatomic molecule in which the two polaritons are separated by a finite "bond length." These states propagate with a negative group velocity in the medium, allowing for a simple preparation and detection scheme, before they slowly decay to pairs of bound Rydberg atoms.
Coulomb edge effects in graphene nanoribbons
NASA Astrophysics Data System (ADS)
Jaskolski, W.; Ayuela, A.
2014-10-01
Coulomb effects in graphene nanoribbons with arbitrary edges are investigated with the use of a mean-field Hubbard model. It was recently shown that chiral ribbons with minimal edges, characterized by the translation vector (n,m), have a similar structure of bands localized around the Fermi energy as pure zigzag ribbons (n-m,0). Here we show that these flat bands in both ribbon cases differ in detail due to the perturbation induced by armchair edge nodes. For chiral ribbons the edge bands split at the zone boundary, where the corresponding bands of (n-m,0) zigzag ribbons are degenerate. Coulomb interactions enhance strongly this splitting and at the same time they bring spin into play. We modify each edge keeping global sublattice balance to find that spin degeneracy can be partially lifted. The breaking of spin-degeneracy depends on the asymmetry between the edges and in some cases leads to spin-polarized currents.
Coulomb crystallization of highly charged ions.
Schmöger, L; Versolato, O O; Schwarz, M; Kohnen, M; Windberger, A; Piest, B; Feuchtenbeiner, S; Pedregosa-Gutierrez, J; Leopold, T; Micke, P; Hansen, A K; Baumann, T M; Drewsen, M; Ullrich, J; Schmidt, P O; López-Urrutia, J R Crespo
2015-03-13
Control over the motional degrees of freedom of atoms, ions, and molecules in a field-free environment enables unrivalled measurement accuracies but has yet to be applied to highly charged ions (HCIs), which are of particular interest to future atomic clock designs and searches for physics beyond the Standard Model. Here, we report on the Coulomb crystallization of HCIs (specifically (40)Ar(13+)) produced in an electron beam ion trap and retrapped in a cryogenic linear radiofrequency trap by means of sympathetic motional cooling through Coulomb interaction with a directly laser-cooled ensemble of Be(+) ions. We also demonstrate cooling of a single Ar(13+) ion by a single Be(+) ion-the prerequisite for quantum logic spectroscopy with a potential 10(-19) accuracy level. Achieving a seven-orders-of-magnitude decrease in HCI temperature starting at megakelvin down to the millikelvin range removes the major obstacle for HCI investigation with high-precision laser spectroscopy.
Multicenter molecular integrals for Slater orbitals of higher principal quantum numbers
NASA Technical Reports Server (NTRS)
Tai, H.
1989-01-01
As was shown earlier by Tai (1979), by using the Fourier-transform technique and properly coupling a pair of two-center exchange integrals, the multicenter molecular integrals can be cast into a simple expression upon which numerical procedures can be directly applied. In this paper, the procedure of Tai is extended to integrals involving orbitals with arbitrarily higher principal quantum number. The derivation is outlined, and the explicit expressions are presented for a three-center nuclear attraction integral and a four-center two-electron Coulomb repulsion integral of arbitrary higher states.
Coulomb impurities in two-dimensional topological insulators
NASA Astrophysics Data System (ADS)
Zhu, Jia-Lin; Li, Guo; Yang, Ning
2017-03-01
Introducing a powerful method, we obtain the exact solutions for a Coulomb impurity in two-dimensional infinite and finite topological insulators. The level order and zero-energy degeneracy of the spectra are found to be quite different between topological trivial and nontrivial phases. For quantum dots of topological insulator, the variation of the edge and Coulomb states with dot size, Coulomb potential, and magnetic field are clearly shown. It is found that for small dots the edge states can be strongly coupled with the Coulomb states and for large dots the edge states are insensitive to the Coulomb fields but sensitive to the magnetic fields.
Coulomb interaction on spin-1 particles
NASA Astrophysics Data System (ADS)
Owen, D. A.; Barrett, R. C.
2003-11-01
Using the electro-weak theory, we find the lowest order perturbative correction to a spin-1 particle in an external Coulomb field. We show this leads to a correction of order (Zα)4 and is independent of the mass of the external field. Previous work with Duffin-Kemmer-Petiau (see Nedjadi and Barrett [J. Math. Phys. 35 (1994) 4517]) and the Proca equation has failed to produce this correction.
Generalized oscillator strength and Coulomb excitation
NASA Astrophysics Data System (ADS)
Chidichimo, Marita C.; Thorsley, Michael D.
2003-02-01
Coulomb interaction is characterized by two nondimensional fundamental quantities: the Sommerfeld parameter η and the adiabaticity parameter ξ=ηf-ηi. In this different approach, we choose these variables to describe the behavior of the generalized oscillator strength (GOS). The expression we obtain is valid for scattering of electrons, positrons, and nuclei by arbitrary targets. We present asymptotic expansions, in the quantal and semiclassical approximation, of the electric dipole GOS.
McPherson, Marla C; Cheng, Hans H; Delany, Mary E
2016-11-04
Marek's disease (MD) is a lymphotropic and oncogenic disease of chickens that can lead to death in susceptible and unvaccinated host birds. The causative pathogen, MD virus (MDV), a highly oncogenic alphaherpesvirus, integrates into host genome near the telomeres. MD occurrence is controlled across the globe by biosecurity, selective breeding for enhanced MD genetic resistance, and widespread vaccination of flocks using attenuated serotype 1 MDV or other serotypes. Despite over 40 years of usage, the specific mechanism(s) of MD vaccine-related immunity and anti-tumor effects are not known. Here we investigated the cytogenetic interactions of commonly used MD vaccine strains of all three serotypes (HVT, SB-1, and Rispens) with the host to determine if all were equally capable of host genome integration. We also studied the dynamic profiles of chromosomal association and integration of the three vaccine strains, a first for MD vaccine research. Our cytogenetic data provide evidence that all three MD vaccine strains tested integrate in the chicken host genome as early as 1 day after vaccination similar to oncogenic strains. However, a specific, transformation-associated virus-host phenotype observed for oncogenic viruses is not established. Our results collectively provide an updated model of MD vaccine-host genome interaction and an improved understanding of the possible mechanisms of vaccinal immunity. Physical integration of the oncogenic MDV genome into host chromosomes along with cessation of viral replication appears to have joint signification in MDV's ability to induce oncogenic transformation. Whereas for MD vaccine serotypes, a sustained viral replication stage and lack of the chromosome-integrated only stage were shared traits during early infection.
Thermoelectrics with Coulomb-coupled quantum dots
NASA Astrophysics Data System (ADS)
Thierschmann, Holger; Sánchez, Rafael; Sothmann, Björn; Buhmann, Hartmut; Molenkamp, Laurens W.
2016-12-01
In this article we review the thermoelectric properties of three terminal devices with Coulomb-coupled quantum dots (QDs) as observed in recent experiments [1,2]. The system we consider consists of two Coulomb-blockade QDs, one of which can exchange electrons with only a single reservoir (heat reservoir), while the other dot is tunnel coupled with two reservoirs at a lower temperature (conductor). The heat reservoir and the conductor interact only via the Coulomb coupling of the quantum dots. It has been found that two regimes have to be considered. In the first one, the heat flow between the two systems is small. In this regime, thermally driven occupation fluctuations of the hot QD modify the transport properties of the conductor system. This leads to an effect called thermal gating. Experiments have shown how this can be used to control charge flow in the conductor by means of temperature in a remote reservoir. We further substantiate the observations with model calculations, and implications for the realisation of an all-thermal transistor are discussed. In the second regime, the heat flow between the two systems is relevant. Here the system works as a nanoscale heat engine, as proposed recently (Sánchez and Büttiker [3]). We review the conceptual idea, its experimental realisation and the novel features arising in this new kind of thermoelectric device such as decoupling of heat and charge flow. xml:lang="fr"
Koufogiannis, E T; Sgouros, N P; Sangriotis, M S
2011-12-01
In most integral image analysis and processing tasks, accurate knowledge of the internal image structure is required. In this paper we present a robust framework for the accurate rectification of perspectively distorted integral images based on multiple line segment detection. The use of multiple line segments increases the overall fault tolerance of our framework providing strong statistical support for the rectification process. The proposed framework is used for the automatic rectification, metric correction, and rotation of distorted integral images. The performance of our framework is assessed over a number of integral images with varying scene complexity and noise levels.
Integrated Deployment Model: A Comprehensive Approach to Transforming the Energy Economy
Werner, M.
2010-11-01
This paper describes the Integrated Deployment model to accelerate market adoption of alternative energy solutions to power homes, businesses, and vehicles through a comprehensive and aggressive approach.
ERIC Educational Resources Information Center
Sahin Izmirli, Özden; Kabakçi Yurdakul, Isil
2014-01-01
An examination of prospective teachers' information and communication technology (ICT) integration skills development in an undergraduate program indicated that the only course available to practice these skills was the teaching practice course. However, the practice and development of these ICT integration skills in the teaching practice course…
Muniraj, Inbarasan; Guo, Changliang; Lee, Byung-Geun; Sheridan, John T
2015-06-15
We present a method of securing multispectral 3D photon-counted integral imaging (PCII) using classical Hartley Transform (HT) based encryption by employing optical interferometry. This method has the simultaneous advantages of minimizing complexity by eliminating the need for holography recording and addresses the phase sensitivity problem encountered when using digital cameras. These together with single-channel multispectral 3D data compactness, the inherent properties of the classical photon counting detection model, i.e. sparse sensing and the capability for nonlinear transformation, permits better authentication of the retrieved 3D scene at various depth cues. Furthermore, the proposed technique works for both spatially and temporally incoherent illumination. To validate the proposed technique simulations were carried out for both the 2D and 3D cases. Experimental data is processed and the results support the feasibility of the encryption method.
A DNase encoded by integrated element CJIE1 inhibits natural transformation of Campylobacter jejuni
Technology Transfer Automated Retrieval System (TEKTRAN)
The species Campylobacter jejuni (C. jejuni) is considered naturally competent for DNA uptake and displays strong genetic diversity. Yet, non-transformable strains and several relatively stable clonal lineages exist. In the present study, the molecular mechanism responsible for the non-transformabil...
Transforming Pedagogies: Integrating 21st Century Skills and Web 2.0 Technology
ERIC Educational Resources Information Center
Tucker, Shelia Y.
2014-01-01
According to (P21), Partnership for 21st Century Skills (n.d.), unless the gap is bridged between how students learn and how they live, today's education system will face irrelevance. The way people work and live has been transformed by demographic, economic, political, technological, and informational forces. Schools must adapt to these…
Transformative Experience: An Integrative Construct in the Spirit of Deweyan Pragmatism
ERIC Educational Resources Information Center
Pugh, Kevin J.
2011-01-01
A sentiment held by Dewey and shared by other educators is that learning should enrich and expand everyday experience. However, this goal has not been a focus of research. In this article, I propose "transformative experience" as a construct capable of reflecting this goal and functioning as an empirical research construct. I discuss the…
Quantum Coulomb systems: some exact results in the atomic limit
NASA Astrophysics Data System (ADS)
Ballenegger, V.; Martin, Ph. A.
2002-04-01
We review a number of exact results concerning the recombined electron-proton gas. The recombination problem can be formulated in precise terms in the atomic limit. In this limit one lets the density and the temperature tend to zero in a coupled way so that the resulting energy-entropy balance favors the formation of certain chemical species. This enables to develop a clear understanding of the dielectric versus conducting behavior in the system. In particular, we give a first principle derivation of the dielectric constant of the dilute atomic gas without presupposing the existence of atoms. The analysis relies on the path integral representation of the Coulomb gas together with Mayer diagrammatic techniques.
NASA Astrophysics Data System (ADS)
Santos, J. C.; Rubini, J.; Silva, L. P. C.; Caetano, R. E.
2015-09-01
The use of two electro-optical modulators linked in series, one for sensing and one for recovering signals, was formerly presented by some of the authors as a solution for interrogation of optical fiber sensor systems based on WLI method. A key feature required from such systems is that half-wave voltage (Vπ) of recovering modulator must be as small as possible. Aiming at meeting this requirement, in this paper it is presented the use of an unbalanced Michelson Interferometer implemented using an integrated optics component as recover interferometer in an optical voltage transformer intended for high voltage measurements.
Rolled-up transformer structure for a radiofrequency integrated circuit (RFIC)
Li, Xiuling; Huang, Wen
2016-05-03
A rolled-up transformer structure comprises a multilayer sheet having a rolled configuration comprising multiple turns about a longitudinal axis. The multilayer sheet comprises more than one conductive pattern layer on a strain-relieved layer, including a first conductive film and a second conductive film separated from the first conductive film in a thickness direction. The first conductive film comprises an even number of primary conductive strips, where each primary conductive strip has a length extending in the rolling direction, and the second conductive film comprises an even number of secondary conductive strips, where each secondary conductive strip has a length extending in the rolling direction. In the rolled configuration, turns of the primary conductive strips and turns of the secondary conductive strips wrap around the longitudinal axis. The primary conductive strips serve as a primary winding and the secondary conductive strips serve as a secondary winding of the rolled-up transformer structure.
Rolled-up transformer structure for a radiofrequency integrated circuit (RFIC)
Li, Xiuling; Huang, Wen
2015-01-27
A rolled-up transformer structure comprises a multilayer sheet having a rolled configuration comprising multiple turns about a longitudinal axis. The multilayer sheet comprises more than one conductive pattern layer on a strain-relieved layer, including a first conductive film and a second conductive film separated from the first conductive film in a thickness direction. The first conductive film comprises an even number of primary conductive strips, where each primary conductive strip has a length extending in the rolling direction, and the second conductive film comprises an even number of secondary conductive strips, where each secondary conductive strip has a length extending in the rolling direction. In the rolled configuration, turns of the primary conductive strips and turns of the secondary conductive strips wrap around the longitudinal axis. The primary conductive strips serve as a primary winding and the secondary conductive strips serve as a secondary winding of the rolled-up transformer structure.
Bazargani, Hamed Pishvai; Burla, Maurizio; Chrostowski, Lukas; Azaña, José
2016-11-01
We experimentally demonstrate high-performance integer and fractional-order photonic Hilbert transformers based on laterally apodized Bragg gratings in a silicon-on-insulator technology platform. The sub-millimeter-long gratings have been fabricated using single-etch electron beam lithography, and the resulting HT devices offer operation bandwidths approaching the THz range, with time-bandwidth products between 10 and 20.
Militello, Kevin T; Chang, Ming-Mei; Simon, Robert D; Lazatin, Justine C
2016-01-01
The ability of students to understand the relationship between genotype and phenotype, and the mechanisms by which genotypes and phenotypes can change is essential for students studying genetics. To this end, we have developed a four-week laboratory called Blue Genes, which is designed to help novice students discriminate between two mechanisms by which the genetic material can be altered: genetic transformation and gene mutation. In the first week of the laboratory, students incubate a plasmid DNA with calcium chloride-treated Escherichia coli JM109 cells and observe a phenotype change from ampicillin sensitive to ampicillin resistant and from white color to blue color on plates containing 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) and isopropyl β-D-thiogalactopyranoside (IPTG). Over the course of the next three weeks, students use a battery of approaches including plasmid DNA isolation experiments, restriction maps, and PCR to differentiate between mutation and transformation. The students ultimately come to the conclusion that the changes in phenotypes are due to genetic transformation and not mutation based on the evidence generated over the four-week period. Pre-laboratory tests and post-laboratory tests indicate that this set of exercises is successful in helping students differentiate between transformation and mutation. The laboratory is designed for underclassmen and is a good prerequisite for an apprentice-based research opportunity, although it is not designed as a class based research experience. Potential modifications and future directions of the laboratory based upon student experiences and assessment are presented.
Particle Diffusion Due to Coulomb Scattering
V. Lebedev and S. Nagaitsev
2002-06-03
Conventionally, the multiple and single particle scattering in a storage ring are considered to be independent. Such an approach is simple and often yields sufficiently accurate results. Nevertheless, there is a class of problems where such an approach is not adequate and the single and multiple scattering need to be considered together. This can be achieved by solving an integro-differential equation for the particle distribution function, which correctly treats particle Coulomb scattering in the presence of betatron motion. A derivation of the equation is presented in the article. A numerical solution for one practical case is also considered.
Nanoplasmonic renormalization and enhancement of Coulomb interactions
NASA Astrophysics Data System (ADS)
Durach, Maxim; Rusina, Anastasia; Klimov, Victor I.; Stockman, Mark I.
2008-08-01
In this paper we propose a general and powerful theory of the plasmonic enhancement of the many-body phenomena resulting in a closed expression for the surface plasmon-dressed Coulomb interaction. We illustrate this theory by computing dressed interaction explicitly for an important example of metal-dielectric nanoshells which exhibits a rich resonant behavior in magnitude and phase. This interaction is used to describe the nanoplasmonic-enhanced FÂ¨orster resonant energy transfer (FRET) between nanocrystal quantum dots near a nanoshell.
Nanoplasmonic renormalization and enhancement of Coulomb interactions
NASA Astrophysics Data System (ADS)
Durach, M.; Rusina, A.; Klimov, V. I.; Stockman, M. I.
2008-10-01
In this paper, we propose a general and powerful theory of the plasmonic enhancement of the many-body phenomena resulting in a closed expression for the surface plasmon-dressed Coulomb interaction. We illustrate this theory by computing the dressed interaction explicitly for an important example of metal-dielectric nanoshells which exhibits a rich resonant behavior in magnitude and phase. This interaction is used to describe the nanoplasmonic-enhanced Förster resonant energy transfer (FRET) between nanocrystal quantum dots near a nanoshell.
Action principle for Coulomb collisions in plasmas
Hirvijoki, Eero
2016-09-14
In this study, an action principle for Coulomb collisions in plasmas is proposed. Although no natural Lagrangian exists for the Landau-Fokker-Planck equation, an Eulerian variational formulation is found considering the system of partial differential equations that couple the distribution function and the Rosenbluth-MacDonald-Judd potentials. Conservation laws are derived after generalizing the energy-momentum stress tensor for second order Lagrangians and, in the case of a test-particle population in a given plasma background, the action principle is shown to correspond to the Langevin equation for individual particles.
NASA Astrophysics Data System (ADS)
Mathuna, Cian Ó.; Wang, Ningning; Kulkarni, Santosh; Roy, Saibal
2013-07-01
This paper introduces the concept of power supply on chip (PwrSoC) which will enable the development of next-generation, functionally integrated, power management platforms with applications in dc-dc conversion, gate drives, isolated power transmission and ultimately, high granularity, on-chip, power management for mixed-signal, SOC chips. PwrSoC will integrate power passives with the power management IC, in a 3D stacked or monolithic form factor, thereby delivering the performance of a highefficiency dc-dc converter within the footprint of a low-efficiency linear regulator. A central element of the PwrSoC concept is the fabrication of power micro-magnetics on silicon to deliver micro-inductors and micro-transformers. The paper details the magnetics on silicon process which combines thin film magnetic core technology with electroplated copper conductors. Measured data for micro-inductors show inductance operation up to 20 MHz, footprints down to 0.5 mm2, efficiencies up to 93% and dc current carrying capability up to 600 mA. Measurements on micro-transformers show voltage gain of approximately - 1 dB at between 10 MHz and 30 MHz. Contribution to the Topical Issue “International Semiconductor Conference Dresden-Grenoble - ISCDG 2012”, Edited by Gérard Ghibaudo, Francis Balestra and Simon Deleonibus.
Schwarzhans, Jan-Philipp; Wibberg, Daniel; Winkler, Anika; Luttermann, Tobias; Kalinowski, Jörn; Friehs, Karl
2016-01-01
The non-conventional yeast Pichia pastoris is a popular host for recombinant protein production in scientific research and industry. Typically, the expression cassette is integrated into the genome via homologous recombination. Due to unknown integration events, a large clonal variability is often encountered consisting of clones with different productivities as well as aberrant morphological or growth characteristics. In this study, we analysed several clones with abnormal colony morphology and discovered unpredicted integration events via whole genome sequencing. These include (i) the relocation of the locus targeted for replacement to another chromosome (ii) co-integration of DNA from the E. coli plasmid host and (iii) the disruption of untargeted genes affecting colony morphology. Most of these events have not been reported so far in literature and present challenges for genetic engineering approaches in this yeast. Especially, the presence and independent activity of E. coli DNA elements in P. pastoris is of concern. In our study, we provide a deeper insight into these events and their potential origins. Steps preventing or reducing the risk for these phenomena are proposed and will help scientists working on genetic engineering of P. pastoris or similar non-conventional yeast to better understand and control clonal variability. PMID:27958335
Revenue Forecasting to Integrate CCC Planning and Resource Allocation for Transformative Leadership
ERIC Educational Resources Information Center
Hovey, Ann
2012-01-01
In recent years the majority of California community colleges evaluated for re-accreditation received sanctions requiring documented improvement in the integration of college planning and budgeting processes. This study explores the challenges colleges face and the best practices utilized by successful colleges in implementing integrated…
Transforming Education into the 21st Century by Integrating 1:1 iPads
ERIC Educational Resources Information Center
Belcher, Kermit E.
2014-01-01
Teachers at Mason County High School are changing from predominantly teacher led instruction to increased student engagement by providing blended learning opportunities through technology integration. Every student and teacher at Mason County High School was provided an iPad as a resource to enhance instruction. The purpose of this case study is…
Improved Shell models for screened Coulomb balls
NASA Astrophysics Data System (ADS)
Bonitz, M.; Kaehlert, H.; Henning, C.; Baumgartner, H.; Filinov, A.
2006-10-01
Spherical Coulomb crystals in dusty plasmas [1] are well described by an isotropic Yukawa-type pair interaction and an external parabolic confinement as was shown by extensive molecular dynamics simulations [2]. A much simpler description is possible with analytical shell models which have been derived for Yukawas plasmas in [3,4]. Here we analyze improved Yukawa shell models which include correlations along the lines proposed for Coulomb crystals in [5]. The shell configurations are efficiently evaluated using a Monte Carlo procedure. [1] O. Arp, A. Piel and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004). [2] M. Bonitz, D. Block, O. Arp, V. Golunychiy, H. Baumgartner, P. Ludwig, A. Piel and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006). [3] H. Totsuji, C. Totsuji, T. Ogawa, and K. Tsuruta, Phys. Rev. E 71, 045401 (2005). [4] C. Henning, M. Bonitz, A. Piel, P. Ludwig, H. Baumgartner, V. Golubnichiy, and D. Block, submitted to Phys. Rev. E [5] W.D. Kraeft and M. Bonitz, J. Phys. Conf. Ser. 35, 94 (2006).
Thermodynamic properties of screened Coulomb balls
NASA Astrophysics Data System (ADS)
Bonitz, M.; Baumgartner, H.; Filinov, A.
2006-10-01
Complex plasmas in parabolic traps [1,2], especially Coulomb balls, can easily reach a strongly coupled state which is of great current interest in many fields, including trapped ions, ultracold plasmas and condensed matter. The advantage of the dust crystals is the direct experimental access to the individual particle positions, allowing for precision comparisons with theoretical models and numerical simulations. In this work the dependence of melting points of mesoscopic spherical crystals on the screening and particle number is analyzed. We present analytical results which are compared with simulation and experimental data [3,4,5]. It is shown that the influence of the screening on structural properties of these mesoscopic systems exhibts also a strong impact on the melting behavior. This analysis is based on Metropolis thermodynamic Monte Carlo simulations to obtain first principle thermodynamic properties of the strongly correlated Coulomb clusters. Finally, our results allow to propose a new non-invasive diagnostic to determine the dust temperature. [1] O. Arp, A. Piel and A. Melzer, Phys. Rev. Lett. 93, 165004 (2004).[2] P. Ludwig, S. Kosse and M. Bonitz, Phys. Rev. E 71, 046403 (2005).[3] M. Bonitz, D. Block, O. Arp, V. Golunychiy, H. Baumgartner, P. Ludwig, A. Piel and A. Filinov, Phys. Rev. Lett. 96, 075001 (2006). [4] O.S. Vaulina, S.A. Khrapak and G.E. Morfill, Phys. Rev. E 66, 016404 (2002). [5] J.P. Schiffer, Phys. Rev. Lett. 88, 205003 (2002)
Coulomb excitation of radioactive {sup 79}Pb
Lister, C.J.; Blumenthal, D.; Davids, C.N.
1995-08-01
The technical challenges expected in experiments with radioactive beams can already be explored by using ions produced in primary reactions. In addition, the re-excitation of these ions by Coulomb excitation allows a sensitive search for collective states that are well above the yrast line. We are building an experiment to study Coulomb excitation of radioactive ions which are separated from beam particles by the Fragment Mass Analyzer. An array of gamma detectors will be mounted at the focal plane to measure the gamma radiation following re-excitation. Five Compton-suppressed Ge detectors and five planar LEPS detectors will be used. The optimum experiment of this type appears to be the study of {sup 79}Rb following the {sup 24}Mg ({sup 58}Ni,3p) reaction. We calculate that about 5 x 10{sup 5} {sup 79}Rb nuclei/second will reach the excitation foil. This rubidium isotope was selected for study as it is strongly produced and is highly deformed, so easily re-excited. The use of a {sup 58}Ni re-excitation foil offers the best yields. After re-excitation the ions will be subsequently transported into a shielded beamdump to prevent the accumulation of activity.
Effect of Coulomb interaction on multi-electronwave packet dynamics
Shiokawa, T.; Takada, Y.; Konabe, S.; Hatsugai, Y.; Muraguchi, M.; Endoh, T.; Shiraishi, K.
2013-12-04
We have investigated the effect of Coulomb interaction on electron transport in a one-dimensional nanoscale structure using a multi-electron wave packet approach. To study the time evolution, we numerically solve the time-dependent Hartree-Fock equation, finding that the electron wave packet dynamics strongly depends on the Coulomb interaction strength. When the Coulomb interaction is large, each electron wave packet moves separately in the presence of an electric field. With weak Coulomb interaction, however, the electron wave packets overlap, forming and moving as one collective wave packet.
Extract transformation loading from OLTP to OLAP data using pentaho data integration
NASA Astrophysics Data System (ADS)
Salaki, R. J.; Waworuntu, J.; Tangkawarow, I. R. H. T.
2016-04-01
The design of the data warehouse in this case is expected to solve the problem of evaluation of learning results as well as the relevance of the information received to support decision-making by the leader. Data warehouse design is very important, which is designed to utilize the existing resources of information. GPA (Grade Point Average) data warehouse can be used for the process of evaluation, decision making and even further planning of the study program of PTIK. The diversity of data sources in the course PTIK make decisionmaking and evaluation process becomes not easier. Pentaho Data Integration is used to integrate data in PTIK easy. CPI data warehouse design with multidimensional database modeling approach using the dimension tables and fact tables.
A Fully Integrated Global Strategic Supply Network - A Critical Enabler of DoD Transformation
2004-01-01
3.1 Supply Chain Management Defined The Council of Logistics Management (CLM) defines Supply Chain Management ( SCM ) as “the process of planning...point of consumption for the purpose of conforming to customers requirements. “1 Effective SCM has become a core...leaders are expecting SCM to provide them improved methods of integrating their businesses with both suppliers and customers, while driving ever higher
Pattern Representation and Evaluation of Data through Integration Correlation, and Transformation
2014-02-01
iterative process to translate the CWA results into requirements for prototype visualizations. Mockup visualizations were developed for an integrated...stream (Milestone 2) as will be detailed later in this report. The results of the cognitive work analysis (reportable outcome 1) and prototype mockups ...reportable outcome 2) are detailed below. Each mockup underwent a series of design iterations to ensure that the visualizations made sense for the
NASA Astrophysics Data System (ADS)
Ngo, Nam Quoc; Song, Yufeng; Lin, Bo
2011-02-01
We present the design and analysis of a wideband and tunable optical Hilbert transformer (OHT) using a tunable waveguide-based finite-impulse response (FIR) filter structure by using the digital filter design method and the Remez algorithm. The tunable Nth-order waveguide-based FIR filter, which simply consists of N delay lines, N tunable couplers, N tunable phase shifters and a combiner, can be tuned, by thermally adjusting the tunable couplers and tunable phase shifters, to tune the bandwidth of an OHT using silica-based planar lightwave circuit (PLC) technology. To demonstrate the effectiveness of the method, the simulation results have an excellent agreement with the theoretical predictions. The tunable OHT can function as a wideband and tunable 90° phase shifter and thus has many potential applications. The two unique features of wideband characteristic (up to ~ 2 THz) and tunable bandwidth (THz tuning range) of the proposed OHT cannot be obtained from the existing OHTs.
Phase-integral solution of the radial Dirac equation
Linnaeus, Staffan
2010-03-15
A phase-integral (WKB) solution of the radial Dirac equation is constructed, retaining perfect symmetry between the two components of the wave function and introducing no singularities except at the classical transition points. The potential is allowed to be the time component of a four-vector, a Lorentz scalar, a pseudoscalar, or any combination of these. The key point in the construction is the transformation from two coupled first-order equations constituting the radial Dirac equation to a single second-order Schroedinger-type equation. This transformation can be carried out in infinitely many ways, giving rise to different second-order equations but with the same spectrum. A unique transformation is found that produces a particularly simple second-order equation and correspondingly simple and well-behaved phase-integral solutions. The resulting phase-integral formulas are applied to unbound and bound states of the Coulomb potential. For bound states, the exact energy levels are reproduced.
InTeGrate: Transforming the Teaching of Geoscience and Sustainability
NASA Astrophysics Data System (ADS)
Blockstein, D.; Manduca, C. A.; Bralower, T. J.; Castendyk, D.; Egger, A. E.; Gosselin, D. C.; Iverson, E. A.; Matson, P. A.; MacGregor, J.; Mcconnell, D. A.; Mogk, D. W.; Nevle, R. J.; Oches, E. A.; Steer, D. N.; Wiese, K.
2012-12-01
InTeGrate is an NSF-funded community project to improve geoscience literacy and build a workforce that can apply geoscience principles to address societal issues. Three workshops offered this year by InTeGrate and its partner, On the Cutting Edge, addressed strategies for bringing together geoscience and sustainability within geoscience courses and programs, in interdisciplinary courses and programs, and in courses and programs in other disciplines or schools including arts and humanities, health science, and business. Participants in all workshops described the power of teaching geoscience in the context of sustainability and the utility of this approach in engaging students with geoscience, including student populations not traditionally represented in the sciences. Faculty involved in both courses and programs seek to teach important skills including the ability to think about systems and to make connections between local observations and challenges and global phenomena and issues. Better articulation of these skills, including learning outcomes and assessments, as well as documenting the relationship between these skills and employment opportunities were identified as important areas for further work. To support widespread integration of geoscience and sustainability concepts, these workshops initiated collections describing current teaching activities, courses, and programs. InTeGrate will continue to build these collections in collaboration with On the Cutting Edge and Building Strong Geoscience Departments, and through open contributions by individual faculty and programs. In addition, InTeGrate began developing new teaching modules and courses. Materials for use in introductory geoscience and environmental science/studies courses, distance learning courses, and courses for education majors are being developed and tested by teams of faculty drawn from at least three institutions, including several members from two-year colleges. An assessment team is
Oscillator-Morse-Coulomb mappings and algebras for constant or position-dependent mass
Quesne, C.
2008-02-15
The bound-state solutions and the su(1,1) description of the d-dimensional radial harmonic oscillator, the Morse, and the D-dimensional radial Coulomb Schroedinger equations are reviewed in a unified way using the point canonical transformation method. It is established that the spectrum generating su(1,1) algebra for the first problem is converted into a potential algebra for the remaining two. This analysis is then extended to Schroedinger equations containing some position-dependent mass. The deformed su(1,1) construction recently achieved for a d-dimensional radial harmonic oscillator is easily extended to the Morse and Coulomb potentials. In the last two cases, the equivalence between the resulting deformed su(1,1) potential algebra approach and a previous deformed shape invariance one generalizes to a position-dependent mass background a well-known relationship in the context of constant mass.
Coulomb crystallization in classical and quantum systems
NASA Astrophysics Data System (ADS)
Bonitz, Michael
2007-11-01
Coulomb crystallization occurs in one-component plasmas when the average interaction energy exceeds the kinetic energy by about two orders of magnitude. A simple road to reach such strong coupling consists in using external confinement potentials the strength of which controls the density. This has been succsessfully realized with ions in traps and storage rings and also in dusty plasma. Recently a three-dimensional spherical confinement could be created [1] which allows to produce spherical dust crystals containing concentric shells. I will give an overview on our recent results for these ``Yukawa balls'' and compare them to experiments. The shell structure of these systems can be very well explained by using an isotropic statically screened pair interaction. Further, the thermodynamic properties of these systems, such as the radial density distribution are discussed based on an analytical theory [3]. I then will discuss Coulomb crystallization in trapped quantum systems, such as mesoscopic electron and electron hole plasmas in coupled layers [4,5]. These systems show a very rich correlation behavior, including liquid and solid like states and bound states (excitons, biexcitons) and their crystals. On the other hand, also collective quantum and spin effects are observed, including Bose-Einstein condensation and superfluidity of bound electron-hole pairs [4]. Finally, I consider Coulomb crystallization in two-component neutral plasmas in three dimensions. I discuss the necessary conditions for crystals of heavy charges to exist in the presence of a light component which typically is in the Fermi gas or liquid state. It can be shown that their exists a critical ratio of the masses of the species of the order of 80 [5] which is confirmed by Quantum Monte Carlo simulations [6]. Familiar examples are crystals of nuclei in the core of White dwarf stars, but the results also suggest the existence of other crystals, including proton or α-particle crystals in dense matter
Scalar vertex operator for bound-state QED in the Coulomb gauge
Holmberg, Johan
2011-12-15
Adkins's result [Phys. Rev. D 34, 2489 (1986)] for the time component of the renormalized vertex operator in Coulomb-gauge QED is separated according to its tensor structure and some of the Feynman parameter integrals are carried out analytically, yielding a form suited for numerical bound-state QED calculations. This modified form is applied to the evaluation of the self-energy shift to the binding energy in hydrogenic ions of high nuclear charge.
NASA Astrophysics Data System (ADS)
Khan, Farrukh I.; Schinn, Dustin S.
2013-08-01
A new business plan that enables policy transformation and resource mobilization at the national and international level, while improving access to resources, will allow the Green Climate Fund to integrate development goals and action on climate change.
The ghost propagator in Coulomb gauge
NASA Astrophysics Data System (ADS)
Watson, P.; Reinhardt, H.
2011-05-01
We present results for a numerical study of the ghost propagator in Coulomb gauge whereby lattice results for the spatial gluon propagator are used as input to solving the ghost Dyson-Schwinger equation. We show that in order to solve completely, the ghost equation must be supplemented by a boundary condition (the value of the inverse ghost propagator dressing function at zero momentum) which determines if the solution is critical (zero value for the boundary condition) or subcritical (finite value). The various solutions exhibit a characteristic behavior where all curves follow the same (critical) solution when going from high to low momenta until `forced' to freeze out in the infrared to the value of the boundary condition. The boundary condition can be interpreted in terms of the Gribov gauge-fixing ambiguity; we also demonstrate that this is not connected to the renormalization. Further, the connection to the temporal gluon propagator and the infrared slavery picture of confinement is discussed.
The ghost propagator in Coulomb gauge
Watson, P.; Reinhardt, H.
2011-05-23
We present results for a numerical study of the ghost propagator in Coulomb gauge whereby lattice results for the spatial gluon propagator are used as input to solving the ghost Dyson-Schwinger equation. We show that in order to solve completely, the ghost equation must be supplemented by a boundary condition (the value of the inverse ghost propagator dressing function at zero momentum) which determines if the solution is critical (zero value for the boundary condition) or subcritical (finite value). The various solutions exhibit a characteristic behavior where all curves follow the same (critical) solution when going from high to low momenta until 'forced' to freeze out in the infrared to the value of the boundary condition. The boundary condition can be interpreted in terms of the Gribov gauge-fixing ambiguity; we also demonstrate that this is not connected to the renormalization. Further, the connection to the temporal gluon propagator and the infrared slavery picture of confinement is discussed.
Tabletop nucleosynthesis driven by cluster Coulomb explosion.
Last, Isidore; Jortner, Joshua
2006-10-27
Coulomb explosion of completely ionized (CH4)n, (NH3)n, and (H2O)n clusters will drive tabletop nuclear reactions of protons with 12C6+, 14N7+, and 16O8+ nuclei, extending the realm of nuclear reactions driven by ultraintense laser-heterocluster interaction. The realization for nucleosynthesis in exploding cluster beams requires complete electron stripping from the clusters (at laser intensities I(M) > or = 10(19) W cm(-2)), the utilization of nanodroplets of radius 300-700 A for vertical ionization, and the attainment of the highest energies for the nuclei (i.e., approximately 30 MeV for heavy nuclei and approximately 3 MeV for protons).
Ion Coulomb Crystals and Their Applications
NASA Astrophysics Data System (ADS)
Drewsen, Michael
The following text will give a brief introduction to the physics of the spatially ordered structures, so-called Coulomb crystals, that appear when confined ions are cooled to sufficiently low temperatures. It will as well briefly comment on the very diverse scientific applications of such crystals, which have emerged in the past two decades. While this document lacks figures and many specific references, it is the hope, not the text will stimulate the reader to dig deeper into one or more of the discussed subjects, and inspire her/him to think about new potential applications. A fully referenced journal article of essentially the same text can be found in Physica B 460, 105 (2015) [1].
Simulating Coulomb collisions in a magnetized plasma
Hinton, Fred L.
2008-04-15
The problem of simulating ion-ion Coulomb collisions in a plasma in a strong magnetic field is considered. No assumption is made about the ion distribution function except that it is independent of the gyrophase angle, consistent with the assumption that the ion gyrofrequency is much larger than the ion-ion collision frequency. A Langevin method is presented which time-advances the components of a particle's velocity parallel and perpendicular to the magnetic field, without following the rapidly changing gyrophase. Although the standard Monte Carlo procedure, which uses random sampling, can be used, it is also possible to use a deterministic sampling procedure, where the samples are determined by the points which would be used in a numerical quadrature formula for moments of the Fokker-Planck Green's function. This should reduce the sampling noise compared with the Monte Carlo collision method.
A coulombic hypothesis of mitochondrial oxidative phosphorylation.
Malpress, F H
1984-08-21
A coulombic hypothesis of mitochondrial oxidative phosphorylation is presented, founded upon the evidence for negative fixed charge formation during electron transport chain activity. The intermediary force is electrostatic (psi H) and not electrochemical (delta mu H). The electrochemical potential of the chemiosmotic hypothesis is identified as a "phantom" parameter which owes its delusive existence to the procedures by which it is measured. The connection between psi H and the conditional delta mu H values is examined; it entails the use of a variable conversion factor, f, where delta mu H (mV) = f psi H, and the concept of the "protonic status" of the diffuse double layer. A number of problems which beset the chemiosmotic view are reappraised in the light of the new interpretation, and find authentic solutions.
Relativistic Coulomb excitation of 88Kr
NASA Astrophysics Data System (ADS)
Moschner, K.; Blazhev, A.; Jolie, J.; Warr, N.; Boutachkov, P.; Bednarczyk, P.; Sieja, K.; Algora, A.; Ameil, F.; Bentley, M. A.; Brambilla, S.; Braun, N.; Camera, F.; Cederkäll, J.; Corsi, A.; Danchev, M.; DiJulio, D.; Fahlander, C.; Gerl, J.; Giaz, A.; Golubev, P.; Górska, M.; Grebosz, J.; Habermann, T.; Hackstein, M.; Hoischen, R.; Kojouharov, I.; Kurz, N.; Mǎrginean, N.; Merchán, E.; Möller, T.; Naqvi, F.; Nara Singh, B. S.; Nociforo, C.; Pietralla, N.; Pietri, S.; Podolyák, Zs.; Prochazka, A.; Reese, M.; Reiter, P.; Rudigier, M.; Rudolph, D.; Sava, T.; Schaffner, H.; Scruton, L.; Taprogge, J.; Thomas, T.; Weick, H.; Wendt, A.; Wieland, O.; Wollersheim, H.-J.
2016-11-01
To investigate the systematics of mixed-symmetry states in N =52 isotones, a relativistic Coulomb excitation experiment was performed during the PreSPEC campaign at the GSI Helmholtzzentrum für Schwerionenforschung to determine E 2 transition strengths to 2+ states of the radioactive nucleus 88Kr. Absolute transition rates could be measured towards the first and third 2+ states. For the latter a mixed-symmetry character is suggested on the basis of the indication for a strong M 1 transition to the fully symmetric 21+ state, extending the knowledge of the N =52 isotones below Z =40 . A comparison with the proton-neutron interacting boson model and shell-model predictions is made and supports the assignment.
Littlewood, Roland; Leavey, Gerard
2013-01-01
The psychological consequences of sexual abuse are generally serious and enduring, particularly when the perpetrator is known and trusted by the survivor. This paper explores the experiences of five contemplative nuns who were sexually abused by priests and the spiritual journeys that followed. In the context of an ethnographic study of contemplative practice, participant observation and in-depth interviews were used to examine the ways that the nuns sought to make sense of their experiences through a long process of solitary introspection. The pursuit of meaning was shaped by religious beliefs relating to forgiveness, sacrifice, and salvation. Thus, trauma was transformed into a symbolic religious narrative that shaped their sense of identity. They were able to restructure core beliefs and to manage their current relationships with priests more securely. They described regaining their spiritual well-being in ways that suggest a form of posttraumatic spiritual growth. We conclude by discussing the findings in the light of the existing literature on the interaction of trauma and spirituality. PMID:23296289
Zhou, Chengfeng; Jiang, Wei; Cheng, Qingzheng; Via, Brian K.
2015-01-01
This research addressed a rapid method to monitor hardwood chemical composition by applying Fourier transform infrared (FT-IR) spectroscopy, with particular interest in model performance for interpretation and prediction. Partial least squares (PLS) and principal components regression (PCR) were chosen as the primary models for comparison. Standard laboratory chemistry methods were employed on a mixed genus/species hardwood sample set to collect the original data. PLS was found to provide better predictive capability while PCR exhibited a more precise estimate of loading peaks and suggests that PCR is better for model interpretation of key underlying functional groups. Specifically, when PCR was utilized, an error in peak loading of ±15 cm−1 from the true mean was quantified. Application of the first derivative appeared to assist in improving both PCR and PLS loading precision. Research results identified the wavenumbers important in the prediction of extractives, lignin, cellulose, and hemicellulose and further demonstrated the utility in FT-IR for rapid monitoring of wood chemistry. PMID:26576321
NASA Astrophysics Data System (ADS)
Cox, J. Neal; Sedayao, J.; Shergill, Gurmeet S.; Villasol, R.; Haaland, David M.
1991-03-01
Fourier transform infrared spectrophotometry (FTIR) is a valuable technique for monitoring thin films used in semiconductor device manufacture. Determinations of the constituent contents in borophosphosilicate (BPSG) phosphosilicate (PSG) silicon oxynitride (SiON:H and spin-on-glass (SOG) thin films are a few applications. Due to the nature of the technique FTIR instrumentation is one of the most extensively computer-dependent pieces of equipment that is likely to be found in a microelectronics plant. In the role of fab monitor or reactor characterization tool FTIR instruments can rapidly generate large amounts of data. Also the drive for greater accuracy and tighter precision is leading to the development of increasingly sophisticated data processing software that tax the computing abilities of most instrument local data stations. By linking a local FTIR data station to a remote minicomputer its capabilities are greatly improved. We discuss three classes of enhancement. First the FTIR in the fab area communicates and interacts in real time with the minicomputer: transferring data segments to it instructing it to perform sophisticated processing and returning the results to the operator in the fab. Characterizations of PSG thin films by this approach are discussed. Second the spectra of large numbers of samples are processed locally. The large database is then transmitted to the minicomputer for study by statistical/graphics software. Results of CVD-reactor spatial profiling experiments for plasma SiON are presented. Third processing of calibration spectra is performed
Dynamical effects in the Coulomb expansion following nuclear fragmentation
Chung, K.C.; Donangelo, R.; Schechter, H.
1987-09-01
The effects of the Coulomb expansion on the fragment kinetic energy spectrum for a fragmentating hot nuclear system is investigated. In particular, /sup 12/C-fragment spectra are calculated and compared with those predicted by the uniform expansion approximation. The results indicate that the energy spectra of fragments are quite sensitive to the details of the Coulomb expansion treatment.
Known-to-Unknown Approach to Teach about Coulomb's Law
ERIC Educational Resources Information Center
Thamburaj, P. K.
2007-01-01
Analogies from life experiences help students understand various relationships presented in an introductory chemistry course. Coulomb's law is a complex relationship encountered in introductory general chemistry. A proper understanding of the relationships between the quantities involved in Coulomb's law is necessary in order for students to…
a Field-Theoretical Investigation of 2-D Coulomb Systems with Short-Range Yukawa Repulsion.
NASA Astrophysics Data System (ADS)
Jargocki, Krzysztof Piotr
The two-dimensional Coulomb gas, consisting of positive and negative charges, is an important system which, on one hand, is equivalent to the vortex sector of the planar X-Y model, and, on the other, to the sine-Gordon field theory. In most treatments the charged particles are assumed to have a repulsive hard core which prevents arbitrarily close approaches. In the present work a new regularization scheme based on a soft short-range Yukawa repulsion between the Coulomb gas particles is presented. This formulation is transcribed into a local sine-Gordon-like field theory involving two Bose fields, one the original massless sine -Gordon field corresponding to the long-range Coulomb interaction and an auxiliary massive field corresponding to the short -range Yukawa repulsion. The resulting Lagrangian is not Hermitian. Using the techniques of functional integration, an effective field theory involving the Coulomb field alone is obtained by integrating out the massive field. The resulting Lagrangian is now Hermitian. Then a generalization of Peierls' inequality is used to make a variational calculation of the ground state energy of the Coulomb system. Unlike in the pure sine-Gordon case the theory has a well-defined ground state energy for (beta)q('2) > 2 (or (beta)c('2) > 8(pi)). A new method is used to derive the Kosterlitz -Thouless renormalization group equations, starting with the original sine-Gordon-like theory. The equations are identical to those found previously by other authors. A wave function renormalization is found to be necessary in addition to the normal ordering discussed by Coleman. A fermionized version of the theory is obtained, using the dictionary provided by Kogut and Susskind, which involves two Fermi fields and an electromagnetic potential. Position -space correlation functions are calculated at the critical point. The effective potential is computed in the one -loop approximation. A nonlinear field theory with derivative couplings is found to
NASA Astrophysics Data System (ADS)
Sandner, Thilo; Grasshoff, Thomas; Schenk, Harald; Kenda, Andreas
2012-03-01
A translatory MOEMS actuator with extraordinary large stroke - especially developed for fast optical path length modulation in miniaturized FTIR-spectrometers (FTS) - is presented. A precise translational out-of-plane oscillation at 500 Hz with large stroke of up to 1.2 mm is realized by means of an optimized MEMS design using four pantograph suspensions of the comparative large mirror plate with 5mm diameter. The MOEMS device is driven electro - statically resonant and is manufactured in a CMOS compatible SOI process. Up to +/- 600 μm amplitude (typically 1mm stroke) has been measured in vacuum of 30 Pa and 50 V driving voltage for an optimized pantograph design enabling reduced gas damping and higher driving efficiency. For FTS system integration the MOEMS actuator has been encapsulated in a hybrid optical vacuum package. In this paper we discuss the thermal influences of packaging technology on MOEMS behaviors more detail.
NASA Astrophysics Data System (ADS)
Cox, J. N.; Sedayao, J.; Shergill, G.; Villasol, R.; Haaland, D. M.
Fourier transform infrared spectrophotometry (FTIR) is a valuable technique for monitoring thin films used in semiconductor device manufacture. Determinations of the constituent contents in borophosphosilicate (BPSG), phosphosilicate (PSG), silicon oxynitride (SiON:H,OH), and spin-on-glass (SOG) thin films are a few applications. Due to the nature of the technique, FTIR instrumentation is one of the most extensively computer-dependent pieces of equipment that is likely to be found in a microelectronics plant. In the role of fab monitor or reactor characterization tool, FTIR instruments can rapidly generate large amounts of data. By linking a local FTIR data station to a remote minicomputer its capabilities are greatly improved. We discuss three caused of enhancement. First, the FTIR in the fab area communicates and interacts in real time with the minicomputer: transferring data segments to it, instructing it to perform sophisticated processing, and returning the result to the operator in the fab. Characterizations of PSG thin films by this approach are discussed. Second, the spectra of large numbers of samples are processed locally. The large database is then transmitted to the minicomputer for study by statistical/graphics software. Results of CVD-reactor spatial profiling experiments for plasma SiON are presented. Third, processing of calibration spectra is performed on the minicomputer to optimize the accuracy and precision of a Partial Least Squares analysis mode. This model is then transferred to the data station in the fab. The analysis of BPSG thin films is discussed in this regard. The prospects for fully automated at-line monitoring and for real-time, in-situ monitoring will be discussed.
Cox, J.N.; Sedayao, J.; Shergill, G.; Villasol, R. ); Haaland, D.M. )
1990-01-01
Fourier transform infrared spectrophotometry (FTIR) is a valuable technique for monitoring thin films used in semiconductor device manufacture. Determinations of the constituent contents in borophosphosilicate (BPSG), phosphosilicate (PSG), silicon oxynitride (SiON:H,OH), and spin-on-glass (SOG) thin films are a few applications. Due to the nature of the technique, FTIR instrumentation is one of the most extensively computer-dependent pieces of equipment that is likely to be found in a microelectronics plant. In the role of fab monitor or reactor characterization tool, FTIR instruments can rapidly generate large amounts of data. By linking a local FTIR data station to a remote minicomputer its capabilities are greatly improved. We discuss three caused of enhancement. First, the FTIR in the fab area communicates and interacts in real time with the minicomputer: transferring data segments to it, instructing it to perform sophisticated processing, and returning the result to the operator in the fab. Characterizations of PSG thin films by this approach are discussed. Second, the spectra of large numbers of samples are processed locally. The large database is then transmitted to the minicomputer for study by statistical/graphics software. Results of CVD-reactor spatial profiling experiments for plasma SiON are presented. Third, processing of calibration spectra is performed on the minicomputer to optimize the accuracy and precision of a Partial Least Squares'' analysis mode. This model is then transferred to the data station in the fab. The analysis of BPSG thin films is discussed in this regard. The prospects for fully automated at-line monitoring and for real-time, in-situ monitoring will be discussed. 10 refs., 4 figs.
NASA Astrophysics Data System (ADS)
Levin, S. B.; Yakovlev, S. L.; Elander, N.
2001-12-01
The three-body Coulomb Green's function asymptotic structure is studied by the stationary phase method for the convolution integral for the case of two charged particles. The stationary phase points are roots of the third degree polinomial with the coefficients depending on the position in configuration space.
Durant, Anne Foss; McDermott, Shawna; Kinney, Gwendolyn; Triner, Trudy
2015-01-01
In early 2010, leaders within Kaiser Permanente (KP) Northern California’s Patient Care Services division embarked on a journey to embrace and embed core tenets of Caring Science into the practice, environment, and culture of the organization. Caring Science is based on the philosophy of Human Caring, a theory articulated by Jean Watson, PhD, RN, AHN-BC, FAAN, as a foundational covenant to guide nursing as a discipline and a profession. Since 2010, Caring Science has enabled KP Northern California to demonstrate its commitment to being an authentic person- and family-centric organization that promotes and advocates for total health. This commitment empowers KP caregivers to balance the art and science of clinical judgment by considering the needs of the whole person, honoring the unique perception of health and healing that each member or patient holds, and engaging with them to make decisions that nurture their well-being. The intent of this article is two-fold: 1) to provide context and background on how a professional practice framework was used to transform the ethic of caring-healing practice, environment, and culture across multiple hospitals within an integrated delivery system; and 2) to provide evidence on how integration of Caring Science across administrative, operational, and clinical areas appears to contribute to meaningful patient quality and health outcomes. PMID:26828076
Transforming trauma healthcare delivery in rural areas by use of an integrated call center
Agrawal, Deepak
2012-01-01
Introduction: There is poor penetration of trauma healthcare delivery in rural areas. On the other hand, mobile penetration in India is now averaging 80% with most families having access to mobile phone. Aims and Objectives: The aim of this study was to assess the implementation and socioeconomic impact of a call center in providing healthcare delivery for patients with head and spinal injuries. Materials and Methods: This was a prospective observational study carried out over a 6-month period at a level I trauma Center in New Delhi, India. A nine-seater call center was outsourced to a private company and the hospital's electronic medical records were integrated with the call-center operations. The call center was given responsibility of maintaining appointments and scheduling clinics for the whole hospital as well as ensuring follow-up visits. Trained call-center staff handled simple patient queries and referred the rest via email to concerned doctors. A telephonic survey was done prior to the start of call-center operations and after 3 months to assess for user satisfaction. Results: The initial cost of outsourcing the call center was Rs 1.6 lakhs (US$ 4000), with a recurring cost of Rs 80,000 (US$ 2000) per month. A total of 484 patients were admitted in the department of Neurosurgery during the study period. Of these, 63% (n=305) were from rural areas. Patients’ overall experience for clinic visits improved markedly following implementation of call center. Patient satisfaction for follow-up visits increased from a mean of 32-96%. Ninety-five percent patients reported a significant decrease in waiting time in clinics 80.4% reporting improved doctor-patient interaction. A total of 52 visits could be postponed/cancelled for patients living in far flung areas resulting in major socioeconomic benefits to these families. Conclusions: As shown by our case study, call centers have the potential to revolutionize delivery of trauma healthcare to rural areas in an
Coupling constant metamorphosis, the Staeckel transform and superintegrability
Post, Sarah
2010-12-23
This paper is dedicated to the memory of Marcos Moshinsky. In this paper, we discuss the important role that coupling constant metamorphosis (CCM) and the Staeckel transform have played in the analysis of superintegrable systems. We explain the relation between the two and in particular show that they coincide when transforming between second-order superintegrable systems. Unlike in the case of second-order superintegrability, the quantum analog of CCM has only been proven for a subclass of systems with integrals of a specific form. We give the proof and as an application show the mapping of a family of superintegrable deformations of the simple harmonic oscillator to an associated family of superintegrable deformations of the Kepler-Coulomb potential.
NASA Astrophysics Data System (ADS)
Tian, Y. P.; Wang, Y.; Jin, X. L.; Huang, Z. L.
2014-09-01
A nonlinear electromagnetic energy harvester directly powering a load resistance is considered in this manuscript. The nonlinearity includes the cubic stiffness and the unavoidable Coulomb friction, and the base excitation is confined to Gaussian white noise. Directly starting from the coupled equations, a novel procedure to evaluate the random responses and the mean output power is developed through the generalized harmonic transformation and the equivalent non-linearization technique. The dependence of the optimal ratio of the load resistance to the internal resistance and the associated optimal mean output power on the internal resistance of the coil is established. The principle of impedance matching is correct only when the internal resistance is infinity, and the optimal mean output power approaches an upper limit as the internal resistance is close to zero. The influence of the Coulomb friction on the optimal resistance ratio and the optimal mean output power is also investigated. It is proved that the Coulomb friction almost does not change the optimal resistance ratio although it prominently reduces the optimal mean output power.
Analytic evaluation of two-center molecular integrals
NASA Technical Reports Server (NTRS)
Tai, H.
1986-01-01
By using the Fourier-transform technique, the explicit expressions for the one-electron - two-center overlap integrals of Slater-type atomic orbitals up to 3d are derived. The final expressions are analytic, simple, and independent of local coordinates. Furthermore, they do not contain the nonclosed-form of exponential integrals which were presented in expressions given in earlier work. It is shown that the two-electron - two-center Coulomb integrals, as well as the hybrid integrals, can simply be expressed in terms of these integrals. The numerical instability arising from the situation in which the exponents of the two orbitals are almost equal is discussed, and a solution for this problem based on a Taylor-series expansion of the integral is suggested.
Coulomb gauge ghost Dyson-Schwinger equation
NASA Astrophysics Data System (ADS)
Watson, P.; Reinhardt, H.
2010-12-01
A numerical study of the ghost Dyson-Schwinger equation in Coulomb gauge is performed and solutions for the ghost propagator found. As input, lattice results for the spatial gluon propagator are used. It is shown that in order to solve completely, the equation must be supplemented by a nonperturbative boundary condition (the value of the inverse ghost propagator dressing function at zero momentum), which determines if the solution is critical (zero value for the boundary condition) or subcritical (finite value). The various solutions exhibit a characteristic behavior where all curves follow the same (critical) solution when going from high to low momenta until forced to freeze out in the infrared to the value of the boundary condition. The renormalization is shown to be largely independent of the boundary condition. The boundary condition and the pattern of the solutions can be interpreted in terms of the Gribov gauge-fixing ambiguity. The connection to the temporal gluon propagator and the infrared slavery picture of confinement is explored.
Coulomb glass in the random phase approximation
NASA Astrophysics Data System (ADS)
Basylko, S. A.; Onischouk, V. A.; Rosengren, A.
2002-01-01
A three-dimensional model of the electrons localized on randomly distributed donor sites of density n and with the acceptor charge uniformly smeared on these sites, -Ke on each, is considered in the random phase approximation (RPA). For the case K=1/2 the free energy, the density of the one-site energies (DOSE) ɛ, and the pair OSE correlators are found. In the high-temperature region (e2n1/3/T)<1 (T is the temperature) RPA energies and DOSE are in a good agreement with the corresponding data of Monte Carlo simulations. Thermodynamics of the model in this region is similar to the one of an electrolyte in the regime of Debye screening. In the vicinity of the Fermi level μ=0 the OSE correlations, depending on sgn(ɛ1.ɛ2) and with very slow decoupling law, have been found. The main result is that even in the temperature range where the energy of a Coulomb glass is determined by Debye screening effects, the correlations of the long-range nature between the OSE still exist.
Femtosecond Laser-Induced Coulomb Explosion Imaging
NASA Astrophysics Data System (ADS)
Karimi, Reza; Liu, Wing-Ki; Sanderson, Joseph
2016-07-01
We review recent progress in the field of Coulomb imaging using femtosecond laser pulses of variable length, referred to as Femtosecond Multiple Pulse Length Spectroscopy (FEMPULS). This method introduces a multi-dimensional approach to the study of the molecular dynamics of the multiply ionized triatomic molecules: CO2, OCS, and N2O. We describe the experimental setup used and the approaches needed to optimize the multi-particle detection, coincidence technique. The results show the degree of high resolution imaging which can be achieved with few cycle pulses, and how the onset of charge resonance enhanced ionization (CREI) can be observed as pulse length is increased. By coupling pulse length variation with Dalitz and Newton plotting techniques, stepwise processes can be identified for all three molecules, giving insight into the dynamics, particularly on the 3+ state, which has been revealed as the doorway state to CREI. Finally, in the case of OCS, pulse length variation is shown to have the potential as a control mechanism, as it modulates the ratio of stepwise to concerted processes.
Electron attraction mediated by Coulomb repulsion
NASA Astrophysics Data System (ADS)
Hamo, A.; Benyamini, A.; Shapir, I.; Khivrich, I.; Waissman, J.; Kaasbjerg, K.; Oreg, Y.; von Oppen, F.; Ilani, S.
2016-07-01
One of the defining properties of electrons is their mutual Coulomb repulsion. However, in solids this basic property may change; for example, in superconductors, the coupling of electrons to lattice vibrations makes the electrons attract one another, leading to the formation of bound pairs. Fifty years ago it was proposed that electrons can be made attractive even when all of the degrees of freedom in the solid are electronic, by exploiting their repulsion from other electrons. This attraction mechanism, termed ‘excitonic’, promised to achieve stronger and more exotic superconductivity. Yet, despite an extensive search, experimental evidence for excitonic attraction has yet to be found. Here we demonstrate this attraction by constructing, from the bottom up, the fundamental building block of the excitonic mechanism. Our experiments are based on quantum devices made from pristine carbon nanotubes, combined with cryogenic precision manipulation. Using this platform, we demonstrate that two electrons can be made to attract each other using an independent electronic system as the ‘glue’ that mediates attraction. Owing to its tunability, our system offers insights into the underlying physics, such as the dependence of the emergent attraction on the underlying repulsion, and the origin of the pairing energy. We also demonstrate transport signatures of excitonic pairing. This experimental demonstration of excitonic pairing paves the way for the design of exotic states of matter.
Deep inelastic scattering near the Coulomb barrier
Gehring, J.; Back, B.; Chan, K.
1995-08-01
Deep inelastic scattering was recently observed in heavy ion reactions at incident energies near and below the Coulomb barrier. Traditional models of this process are based on frictional forces and are designed to predict the features of deep inelastic processes at energies above the barrier. They cannot be applied at energies below the barrier where the nuclear overlap is small and friction is negligible. The presence of deep inelastic scattering at these energies requires a different explanation. The first observation of deep inelastic scattering near the barrier was in the systems {sup 124,112}Sn + {sup 58,64}Ni by Wolfs et al. We previously extended these measurements to the system {sup 136}Xe + {sup 64}Ni and currently measured the system {sup 124}Xe + {sup 58}Ni. We obtained better statistics, better mass and energy resolution, and more complete angular coverage in the Xe + Ni measurements. The cross sections and angular distributions are similar in all of the Sn + Ni and Xe + Ni systems. The data are currently being analyzed and compared with new theoretical calculations. They will be part of the thesis of J. Gehring.
Multilevel Monte Carlo simulation of Coulomb collisions
Rosin, M.S.; Ricketson, L.F.; Dimits, A.M.; Caflisch, R.E.; Cohen, B.I.
2014-10-01
We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε, the computational cost of the method is O(ε{sup −2}) or O(ε{sup −2}(lnε){sup 2}), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε{sup −3}) for direct simulation Monte Carlo or binary collision methods. We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10{sup −5}. We discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.
Electron attraction mediated by Coulomb repulsion.
Hamo, A; Benyamini, A; Shapir, I; Khivrich, I; Waissman, J; Kaasbjerg, K; Oreg, Y; von Oppen, F; Ilani, S
2016-07-21
One of the defining properties of electrons is their mutual Coulomb repulsion. However, in solids this basic property may change; for example, in superconductors, the coupling of electrons to lattice vibrations makes the electrons attract one another, leading to the formation of bound pairs. Fifty years ago it was proposed that electrons can be made attractive even when all of the degrees of freedom in the solid are electronic, by exploiting their repulsion from other electrons. This attraction mechanism, termed 'excitonic', promised to achieve stronger and more exotic superconductivity. Yet, despite an extensive search, experimental evidence for excitonic attraction has yet to be found. Here we demonstrate this attraction by constructing, from the bottom up, the fundamental building block of the excitonic mechanism. Our experiments are based on quantum devices made from pristine carbon nanotubes, combined with cryogenic precision manipulation. Using this platform, we demonstrate that two electrons can be made to attract each other using an independent electronic system as the 'glue' that mediates attraction. Owing to its tunability, our system offers insights into the underlying physics, such as the dependence of the emergent attraction on the underlying repulsion, and the origin of the pairing energy. We also demonstrate transport signatures of excitonic pairing. This experimental demonstration of excitonic pairing paves the way for the design of exotic states of matter.
Coulomb gauge model for hidden charm tetraquarks
NASA Astrophysics Data System (ADS)
Xie, W.; Mo, L. Q.; Wang, Ping; Cotanch, Stephen R.
2013-08-01
The spectrum of tetraquark states with hidden charm is studied within an effective Coulomb gauge Hamiltonian approach. Of the four independent color schemes, two are investigated, the (qcbar)1(cqbar)1 singlet-singlet (molecule) and the (qc)3(qbarcbar)3 triplet-triplet (diquark), for selected JPC states using a variational method. The predicted masses of triplet-triplet tetraquarks are roughly a GeV heavier than the singlet-singlet states. There is also an interesting flavor dependence with (qqbar)1 (ccbar1) states about half a GeV lighter than (qcbar)1(qbarc)1. The lightest 1++ and 1-- predictions are in agreement with the observed X (3872) and Y (4008) masses suggesting they are molecules with ωJ / ψ and ηhc, rather than D*Dbar* and DDbar, type structure, respectively. Similarly, the lightest isovector 1++ molecule, having a ρJ / ψ flavor composition, has mass near the recently observed charged Zc (3900) value. These flavor configurations are consistent with observed X, Y and Zc decays to ππJ / ψ.
Multilevel Monte Carlo simulation of Coulomb collisions
Rosin, M. S.; Ricketson, L. F.; Dimits, A. M.; ...
2014-05-29
We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε , the computational cost of the method is O(ε–2) or (ε–2(lnε)2), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε–3) for direct simulation Monte Carlo or binary collision methods.more » We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10–5. Lastly, we discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.« less
Multilevel Monte Carlo simulation of Coulomb collisions
Rosin, M. S.; Ricketson, L. F.; Dimits, A. M.; Caflisch, R. E.; Cohen, B. I.
2014-05-29
We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε , the computational cost of the method is O(ε^{–2}) or (ε^{–2}(lnε)^{2}), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε^{–3}) for direct simulation Monte Carlo or binary collision methods. We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10^{–5}. Lastly, we discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.
Positron scattering from hydrogen atom with screened Coulomb potentials
Ghoshal, Arijit; Nayek, Sujay; Kamali, M. Z. M.; Ratnavelu, K.
2014-03-05
Elastic positron-hydrogen collisions with screened Coulomb potentials have been investigated using a second-order distorted wave Born approximation in the momentum space. Two types of potentials have been considered, namely, static screened Coulomb potential and exponential cosine-screened Coulomb potential. Using a simple variationally determined hydrogenic wave function it has been possible to obtain the scattering amplitude in a closed form. A detailed study has been made on the differential and total cross sections in the energy range 20–300 eV.
Verification of Coulomb order in a storage ring
Hasse, Rainer W.
1999-12-10
We verify theoretically that the anomalous longitudinal temperature reduction of strongly electron cooled heavy ions in the ESR at very low density is explained by the fact that there is no intrabeam scattering and that the particles by their Coulomb repulsion cannot pass each other any more. At the achievable momentum spreads Coulomb order is reached at particle distances of the order of centimeters. It is also shown that under the given experimental conditions in the proton NAP-M experiment of 1980 intrabeam heating counteracts Coulomb order.
Verification of Coulomb Order in a Storage Ring
Rainer W. Hasse
1999-12-31
We verify theoretically that the anomalous longitudinal temperature reduction of strongly electron cooled heavy ions in the ESR at very low density is explained by the fact that there is no intrabeam scattering and that the particles by their Coulomb repulsion cannot pass each other any more. At the achievable momentum spreads Coulomb order is reached at particle distances of the order of centimeters. It is also shown that under the given experimental conditions in the proton NAP-M experiment of 1980 intrabeam heating counteracts Coulomb order.
Classical Coulomb blockade of a silicon nanowire dot
NASA Astrophysics Data System (ADS)
Huang, Shaoyun; Fukata, Naoki; Shimizu, Maki; Yamaguchi, Tomohiro; Sekiguchi, Takashi; Ishibashi, Koji
2008-05-01
Single electron transistors (SETs) have been fabricated with an individual n-type single-crystal silicon nanowire (SiNW) that was grown by a catalytic chemical vapor deposition technique, and their transport properties have been measured in low temperatures. The SiNW-SET in the present work exhibited well pronounced Coulomb oscillations in a wide gate voltage range from -10to10V, featuring in uniform peak height, uniform full width at half maximum, and equidistant peak spacing. The charging energy turned out to be 64μeV. The temperature dependence of Coulomb oscillations revealed that the dot worked within the classical Coulomb blockade model.
Safouhi, Hassan . E-mail: hassan.safouhi@ualberta.ca; Berlu, Lilian
2006-07-20
Molecular overlap-like quantum similarity measurements imply the evaluation of overlap integrals of two molecular electronic densities related by Dirac delta function. When the electronic densities are expanded over atomic orbitals using the usual LCAO-MO approach (linear combination of atomic orbitals), overlap-like quantum similarity integrals could be expressed in terms of four-center overlap integrals. It is shown that by introducing the Fourier transform of delta Dirac function in the integrals and using the Fourier transform approach combined with the so-called B functions, one can obtain analytic expressions of the integrals under consideration. These analytic expressions involve highly oscillatory semi-infinite spherical Bessel functions, which are the principal source of severe numerical and computational difficulties. In this work, we present a highly efficient algorithm for a fast and accurate numerical evaluation of these multicenter overlap-like quantum similarity integrals over Slater type functions. This algorithm is based on the SD-bar approach due to Safouhi. Recurrence formulae are used for a better control of the degree of accuracy and for a better stability of the algorithm. The numerical result section shows the efficiency of our algorithm, compared with the alternatives using the one-center two-range expansion method, which led to very complicated analytic expressions, the epsilon algorithm and the nonlinear D-bar transformation.
NASA Astrophysics Data System (ADS)
Bonhivers, Jean-Christophe
The increase in production of goods over the last decades has led to the need for improving the management of natural resources management and the efficiency of processes. As a consequence, heat integration methods for industry have been developed. These have been successful for the design of new plants: the integration principles are largely employed, and energy intensity has dramatically decreased in many processes. Although progress has also been achieved in integration methods for retrofit, these methods still need further conceptual development. Furthermore, methodological difficulties increase when trying to retrofit heat exchange networks that are closely interrelated to water networks, such as the case of pulp and paper mills. The pulp and paper industry seeks to increase its profitability by reducing production costs and optimizing supply chains. Recent process developments in forestry biorefining give this industry the opportunity for diversification into bio-products, increasing potential profit margins, and at the same time modernizing its energy systems. Identification of energy strategies for a mill in a changing environment, including the possibility of adding a biorefinery process on the industrial site, requires better integration methods for retrofit situations. The objective of this thesis is to develop an energy integration method for the retrofit of industrial systems and the transformation of pulp and paper mills, ant to demonstrate the method in case studies. Energy is conserved and degraded in a process. Heat can be converted into electricity, stored as chemical energy, or rejected to the environment. A systematic analysis of successive degradations of energy between the hot utilities until the environment, through process operations and existing heat exchangers, is essential in order to reduce the heat consumption. In this thesis, the "Bridge Method" for energy integration by heat exchanger network retrofit has been developed. This method
ERIC Educational Resources Information Center
Stonemeier, Jennifer; Trader, Barbara; Kingston, Mary; Richards, Curtis; Blank, Rolf; East, Bill
2014-01-01
The SWIFT Center (Schoolwide Integrated Framework for Transformation) is an initiative to bring about educational equity district by district until all students excel, including students with the most profound needs. As the national technical assistance center to build schoolwide inclusive practices to improve academic and behavioral outcomes for…
Technology Transfer Automated Retrieval System (TEKTRAN)
Plant Transformation Technologies is a comprehensive, authoritative book focusing on cutting-edge plant biotechnologies, offering in-depth, forward-looking information on methods for controlled and accurate genetic engineering. In response to ever-increasing pressure for precise and efficient integr...
Zhang Songbin; Wang Jianguo; Janev, R. K.
2010-01-15
The effects of Coulomb interaction screening on electron-hydrogen atom excitation in the n=2 threshold region are investigated by using the R-matrix method with pseudostates. The interaction screening lifts the l degeneracy of n=2 Coulomb energy level, producing two distinct thresholds for 2s and 2p states. The phenomenon of transformation of {sup 1,3}P and {sup 1}D Feshbach resonances into shape-type resonances is observed when they pass across the 2s and 2p threshold, respectively, as the interaction screening increases. It is shown that this resonance transformation leads to dramatic effects in the 1s->2s and 1s->2p excitation collision strengths in the n=2 threshold collision energy region.
Thermodynamic properties of the magnetized Coulomb crystal lattices
NASA Astrophysics Data System (ADS)
Kozhberov, A. A.
2016-08-01
It is thought that Coulomb crystals of ions with hexagonal close-packed lattice may form in the crust of strongly-magnetized neutron stars (magnetars). In this work we are trying to verify this prediction assuming that the direction of the magnetic field corresponds to the minimum of the zero-point energy. We also continue a detailed study of vibration modes and thermodynamic properties of magnetized Coulomb crystals in a wide range of temperatures and magnetic fields. It is demonstrated that the total Helmholtz free energy of the body-centered cubic Coulomb crystal is always lower than that of the Coulomb crystal with hexagonal close-packed or face-centered cubic lattice, which casts doubt on the hypothesis above.
Multifragmentation: Surface and Coulomb instabilities of sheets, bubbles, and donuts
Moretto, L.G.; Tso, Kin; Wozniak, G.J.
1993-08-01
Disks, bubbles, and donuts have been observed in dynamical calculations of heavy ion collisions. These shapes are subject to a variety of surface and Coulomb instabilities. These instabilities are identified and analyzed in terms of their relevance to multifragmentation.
Constants of motion in deformed oscillator and Coulomb systems
NASA Astrophysics Data System (ADS)
Hakobyan, Tigran; Nersessian, Armen; Shmavonyan, Hovhannes
2017-03-01
In this note we propose a unified description for the constants of motion for superintegrable deformations of the oscillator and Coulomb systems on N-dimensional Euclidean space, sphere and hyperboloid.
Li, Fuzhong
2014-03-01
Tai Ji Quan, developed as a martial art, has traditionally served multiple purposes, including self-defense, competition/performance, and health promotion. With respect to health, the benefits historically and anecdotally associated with Tai Ji Quan are now being supported by scientific and clinical research, with mounting evidence indicating its potential value in preventing and managing various diseases and improving well-being and quality of life in middle-aged and older adults. The research findings produced to date have both public health significance and clinical relevance. However, because of its roots in the martial arts, transforming traditional Tai Ji Quan movements and training approaches into contemporary therapeutic programs and functional applications is needed to maximize its ultimate utility. This paper addresses this issue by introducing Tai Ji Quan: Moving for Better Balance, a functional therapy that involves the use of Tai Ji Quan principles and Yang-style-based movements to form an innovative, contemporary therapeutic approach that integrates motor, sensory, and cognitive components to improve postural control, gait, and mobility for older adults and those who have neurodegenerative movement impairments. It provides a synergy of traditional and contemporary Tai Ji Quan practice with the ultimate goal of improving balance and gait, enhancing performance of daily functional tasks, and reducing incidence of falls among older adults.
Li, Fuzhong
2014-01-01
Tai Ji Quan, developed as a martial art, has traditionally served multiple purposes, including self-defense, competition/performance, and health promotion. With respect to health, the benefits historically and anecdotally associated with Tai Ji Quan are now being supported by scientific and clinical research, with mounting evidence indicating its potential value in preventing and managing various diseases and improving well-being and quality of life in middle-aged and older adults. The research findings produced to date have both public health significance and clinical relevance. However, because of its roots in the martial arts, transforming traditional Tai Ji Quan movements and training approaches into contemporary therapeutic programs and functional applications is needed to maximize its ultimate utility. This paper addresses this issue by introducing Tai Ji Quan: Moving for Better Balance, a functional therapy that involves the use of Tai Ji Quan principles and Yang-style-based movements to form an innovative, contemporary therapeutic approach that integrates motor, sensory, and cognitive components to improve postural control, gait, and mobility for older adults and those who have neurodegenerative movement impairments. It provides a synergy of traditional and contemporary Tai Ji Quan practice with the ultimate goal of improving balance and gait, enhancing performance of daily functional tasks, and reducing incidence of falls among older adults. PMID:25126445
Aftershock triggering by complete Coulomb stress changes
Kilb, Debi; Gomberg, J.; Bodin, P.
2002-01-01
We examine the correlation between seismicity rate change following the 1992, M7.3, Landers, California, earthquake and characteristics of the complete Coulomb failure stress (CFS) changes (??CFS(t)) that this earthquake generated. At close distances the time-varying "dynamic" portion of the stress change depends on how the rupture develops temporally and spatially and arises from radiated seismic waves and from permanent coseismic fault displacement. The permanent "static" portion (??CFS) depends only on the final coseismic displacement. ??CFS diminishes much more rapidly with distance than the transient, dynamic stress changes. A common interpretation of the strong correlation between ??CFS and aftershocks is that load changes can advance or delay failure. Stress changes may also promote failure by physically altering properties of the fault or its environs. Because it is transient, ??CFS(t) can alter the failure rate only by the latter means. We calculate both ??CFS and the maximum positive value of ??CFS(t) (peak ??CFS(t)) using a reflectivity program. Input parameters are constrained by modeling Landers displacement seismograms. We quantify the correlation between maps of seismicity rate changes and maps of modeled ??CFS and peak ??CFS(t) and find agreement for both models. However, rupture directivity, which does not affect ??CFS, creates larger peak ??CFS(t) values northwest of the main shock. This asymmetry is also observed in seismicity rate changes but not in ??CFS. This result implies that dynamic stress changes are as effective as static stress changes in triggering aftershocks and may trigger earthquakes long after the waves have passed.
Uniform derivation of Coulomb collisional transport thanks to Debye shielding
NASA Astrophysics Data System (ADS)
Escande, Dominique; Elskens, Yves; Doveil, Fabrice
2016-10-01
The effective potential acting on particles in plasmas being essentially the Debye-shielded Coulomb potential, the particles collisional transport in thermal equilibrium is calculated for all impact parameters b, with a convergent expression reducing to Rutherford scattering for small b, in agreement with both usual expressions holding for large b and small b. No cutoff at the Debye length scale is needed, and the Coulomb logarithm is only slightly modified.
A New Hybrid STEP/Coulomb model for Aftershock Forecasting
NASA Astrophysics Data System (ADS)
Steacy, S.; Jimenez, A.; Gerstenberger, M.
2014-12-01
Aftershock forecasting models tend to fall into two classes - purely statistical approaches based on clustering, b-value, and the Omori-Utsu law; and Coulomb rate-state models which relate the forecast increase in rate to the magnitude of the Coulomb stress change. Recently, hybrid models combining physical and statistical forecasts have begun to be developed, for example by Bach and Hainzl (2012) and Steacy et al. (2013). The latter approach combined Coulomb stress patterns with the STEP (short-term earthquake probability) model by redistributing expected rate from areas with decreased stress to regions where the stress had increased. The chosen 'Coulomb Redistribution Parameter' (CRP) was 0.93, based on California earthquakes, which meant that 93% of the total rate was expected to occur where the stress had increased. The model was tested against the Canterbury sequence and the main result was that the new model performed at least as well as, and often better than, STEP when tested against retrospective data but that STEP was generally better in pseudo-prospective tests that involved data actually available within the first 10 days of each event of interest. The authors suggested that the major reason for this discrepancy was uncertainty in the slip models and, particularly, in the geometries of the faults involved in each complex major event. Here we develop a variant of the STEP/Coulomb model in which the CRP varies based on the percentage of aftershocks that occur in the positively stressed areas during the forecast learning period. We find that this variant significantly outperforms both STEP and the previous hybrid model in almost all cases, even when the input Coulomb model is quite poor. Our results suggest that this approach might be more useful than Coulomb rate-state when the underlying slip model is not well constrained due to the dependence of that method on the magnitude of the Coulomb stress change.
NASA Astrophysics Data System (ADS)
Kagan, M. Yu.; Val'kov, V. V.; Aksenov, S. V.
2017-01-01
We present an analytical and numerical investigation of the spectral and transport properties of a quadruple quantum-dot (QQD) structure which is one of the popular low-dimensional systems in the context of fundamental quantum physics study, future electronic applications, and quantum calculations. The density of states, occupation numbers, and conductance of the structure were analyzed using the nonequilibrium Green's functions in the tight-binding approach and the equation-of-motion method. In particular the anisotropy of hopping integrals and on-site electron energies as well as the effects of the finite intra- and interdot Coulomb interactions were investigated. It was found out that the anisotropy of the kinetic processes in the system leads to the Fano-Feshbach asymmetrical peak. We demonstrated that the conductance of the QQD device has a wide insulating band with steep edges separating triple-peak structures if the intradot Coulomb interactions are taken into account. The interdot Coulomb correlations between the central QDs result in the broadening of this band and the occurrence of an additional band with low conductance due to the Fano antiresonances. It was shown that in this case the conductance of the anisotropic QQD device can be dramatically changed by tuning the anisotropy of on-site electron energies.
NASA Astrophysics Data System (ADS)
Leclerc, Arnaud; Jolicard, Georges
2015-06-01
A global solution of the Schrödinger equation for explicitly time-dependent Hamiltonians is derived by integrating the nonlinear differential equation associated with the time-dependent wave operator. A fast iterative solution method is proposed in which, however, numerous integrals over time have to be evaluated. This internal work is done using a numerical integrator based on fast Fourier transforms (FFT). The case of a transition between two potential wells of a model molecule driven by intense laser pulses is used as an illustrative example. This application reveals some interesting features of the integration technique. Each iteration provides a global approximate solution on grid points regularly distributed over the full time propagation interval. Inside the convergence radius, the complete integration is competitive with standard algorithms, especially when high accuracy is required.
Ultrafast dynamics of Coulomb correlated excitons in GaAs quantum wells
Mycek, M.A. |
1995-12-01
The author measures the transient nonlinear optical response of room temperature excitons in gallium arsenide quantum wells via multi-wave mixing experiments. The dynamics of the resonantly excited excitons is directly reflected by the ultrafast decay of the induced nonlinear polarization, which radiates the detected multi-wave mixing signal. She characterizes this ultrafast coherent emission in both amplitude and phase, using time- and frequency-domain measurement techniques, to better understand the role of Coulomb correlation in these systems. To interpret the experimental results, the nonlinear optical response of a dense medium is calculated using a model including Coulomb interaction. She contributes three new elements to previous theoretical and experimental studies of these systems. First, surpassing traditional time-integrated measurements, she temporally resolves the amplitude of the ultrafast coherent emission. Second, in addition to measuring the third-order four-wave mixing signal, she also investigates the fifth-order six-wave mixing response. Third, she characterizes the ultrafast phase dynamics of the nonlinear emission using interferometric techniques with an unprecedented resolution of approximately 140 attoseconds. The author finds that effects arising from Coulomb correlation dominate the nonlinear optical response when the density of excitons falls below 3 {times} 10{sup 11} cm{sup {minus}2}, the saturation density. These signatures of Coulomb correlation are investigated for increasing excitation density to gradually screen the interactions and test the validity of the model for dense media. The results are found to be qualitatively consistent with both the predictions of the model and with numerical solutions to the semiconductor Bloch equations. Importantly, the results also indicate current experimental and theoretical limitations, which should be addressed in future research.
Coulomb excitation of states in 238U
NASA Astrophysics Data System (ADS)
McGowan, F. K.; Milner, W. T.
1994-05-01
Twenty-two states in 238U have been observed with 18 MeV 4He ions on a thick target. Eight 2 + states between 966 and 1782 keV and three 3 - states are populated by direct E2 and E3, respectively. The remaining states are either weakly excited by multiple Coulomb excitation and /or populated by the γ-ray decay of the directly excited states. Spin assignments are based on γ-ray angular distributions. Reduced transition probabilities have been deduced from the γ-ray yields. The B(E2) values for excitation of the 2 + states range from 0.10 to 3.0 W.u. (281 W.u. for the first 2 + state). For the 3 states, the B(E3, 0 → 3 -) values are 7.1, 7.8, and 24.2 W.u. Several of the 2 + states have decay branches to the one-phonon states with B(E2) values between 27 and 56 W.u. which are an order of magnitude larger than the B(E2) values between the one- and zero-phonon states. This disagrees with our present understanding of collectivity in nuclei if these 2 + states are considered to be collective two-phonon excitations. However, the excitation energies of these 2 + states with respect to the one-phonon states are only 1.3 to 1.6. The B(E1) values for 17 transitions between the positive- and negative-parity states range between 10 -3 and 10 -7 W.u. The B(E1) branching ratios for many of these transitions have large deviations from the Alaga-rule predictions. These deviations can be understood by the strong Coriolis coupling between the states of the one-phonon octupole quadruplet in deformed nuclei. The general features of the experimental results for the B(E3) values are reproduced by the microscopic calculations of Neergård and Vogel when the Coriolis coupling between the states of the octupole quadruplet is included.
Coulomb excitation of states in 232Th
NASA Astrophysics Data System (ADS)
McGowan, F. K.; Milner, W. T.
1993-09-01
Twenty-five states in 232Th have been observed with 18 MeV 4He ions on a thick target. Eleven 2 + states between 774 and 1554 keV and three 3 - states are populated by direct E2 and E3, respectively. The remaining states are either weakly excited by multiple Coulomb excitation and/or populated by the decay of the directly excited states. Spin assignments are based on γ-ray angular distributions. Reduced transition probabilities have been deduced from the γ-ray yields. The B(E2) values for excitation of the 2 + states range from 0.024 to 3.5 W.u. (222 W.u. for the first 2 + state). For the 3 - states, the B(E3,0 → 3 -) values are 1.7, 11, and 24 W.u. A possible two-phonon state at 1554 keV, which is nearly harmonic, decays to four members of the one-phonon states, to the ground-state band, and to the K = 0 - octupole band. The B(E2) value for excitation of this state is 0.66 ± 0.05 W.u. and the B(E1) values for decay of this state are (2 and 6)×10 -4 W.u. The B(E2) values between two- and one-phonon vibrational states range between 16 and 53 W.u. which are an order of magnitude larger than the B(E2) values between the one- and zero-phonon states. This disagrees with our present understanding of collectivity in nuclei if this 2 + state is considered to be a collective two-phonon excitation. The 2 + states at 1477 and 1387 keV, which are also nearly harmonic, are possible candidates with two-phonon structure. The agreement between the experimental results and the microscopic calculations by Neergård and Vogel of the B(E3,0 → 3) for the 3 - members of the one-phonon octupole quadruplet is satisfactory when the Coriolis coupling between the states with K and K ± 1 is included. The B(E1) branching ratios for transitions from the 3 - and 1 - states to the ground-state band have large deviations from the Alaga-rule predictions. These deviations can be understood by the strong Coriolis coupling between the states of the octupole quadruplet in deformed nuclei.
Coulomb stress transfer and tectonic loading preceding the 2002 Denali fault earthquake
Bufe, C.G.
2006-01-01
Pre-2002 tectonic loading and Coulomb stress transfer are modeled along the rupture zone of the M 7.9 Denali fault earthquake (DFE) and on adjacent segments of the right-lateral Denali-Totschunda fault system in central Alaska, using a three-dimensional boundary-element program. The segments modeled closely follow, for about 95??, the arc of a circle of radius 375 km centered on an inferred asperity near the northeastern end of the intersection of the Patton Bay fault with the Alaskan megathrust under Prince William Sound. The loading model includes slip of 6 mm/yr below 12 km along the fault system, consistent with rotation of the Wrangell block about the asperity at a rate of about 1??/m.y. as well as slip of the Pacific plate at 5 cm/yr at depth along the Fairweather-Queen Charlotte transform fault system and on the Alaska megathrust. The model is consistent with most available pre-2002 Global Positioning System (GPS) displacement rate data. Coulomb stresses induced on the Denali-Totschunda fault system (locked above 12 km) by slip at depth and by transfer from the M 9.2 Prince William Sound earthquake of 1964 dominated the changing Coulomb stress distribution along the fault. The combination of loading (???70-85%) and coseismic stress transfer from the great 1964 earthquake (???15-30%) were the principal post-1900 stress factors building toward strike-slip failure of the northern Denali and Totschunda segments in the M 7.9 earthquake of November 2002. Postseismic stresses transferred from the 1964 earthquake may also have been a significant factor. The M 7.2-7.4 Delta River earthquake of 1912 (Carver et al., 2004) may have delayed or advanced the timing of the DFE, depending on the details and location of its rupture. The initial subevent of the 2002 DFE earthquake was on the 40-km Susitna Glacier thrust fault at the western end of the Denali fault rupture. The Coulomb stress transferred from the 1964 earthquake moved the Susitna Glacier thrust fault uniformly
Maruyama, K; Oda, K
1984-01-01
Simian virus 40 (SV40) DNA insertions from SV40-transformed mouse cell line W-2K-11 and its revertants M18, M31, and M42 were cloned. W-2K-11 cells contain 1.5 copies of the SV40 sequences in a partially tandem duplicated form. The endpoints of the viral sequences at the virus-host junctions are located very close to those reported by others, indicating that there are some preferred sites for integration and rearrangement in SV40 sequences. One flanking cellular sequence is a long stretch of adenine and thymine with repeated AAAT, and the other is a stretch of guanine and cytosine with repeated CCG. There are patchy homologies between the flanking cellular sequences and the corresponding parental SV40 sequences. The sequences around both junctions were retained in all the revertants, whereas most of the internal SV40 sequences coding for large T antigen were deleted. The coding sequences for small T antigen are intact, and small T antigen was expressed in all the revertants. The fragments cloned from M18 and M42 were identical and 3.9 kilobases of SV40 sequences were deleted. The parental SV40 sequences around the deletion site have sequences capable of forming a secondary structure which might reduce the effective distance between the two regions. The SV40 DNA retained in M31 is colinear with SV40 virion DNA, and a unit length of SV40 DNA was deleted within the SV40 sequences present in W-2K-11 cells. These results indicated that two types of deletion occurred during the reversion, one between homologous sequences and the other between nonhomologous sequences. Images PMID:6319747
Stable and Critical Noncohesive Coulomb Wedges: Exact Elastic Solutions
NASA Astrophysics Data System (ADS)
Wang, K.; Hu, Y.
2004-12-01
The theory of critically tapered Coulomb wedge has been successfully applied to model active fold-and-thrust belts or submarine accretionary prisms. Brittle mountain building is episodic in nature, controlled by changes in basal friction, erosion and sedimentation, and hydrogeology. Sediment accretion may be modulated by great subduction earthquakes. Between deformation episodes and/or during transition between compressional and extensional tectonics, the Coulomb wedges are stable (i.e., supercritical), to which the critical taper theory does not apply. In this work, we provide an exact elastic solution for stable wedges based on Airy stress functions. The stress equilibrium equation and definition of basal friction and basal and internal pore fluid pressure ratios are exactly the same as those used for Dahlen's [1984] exact solution for critical noncohesive Coulomb wedges, but internal friction μ becomes irrelevant. Given elastic - perfectly Coulomb-plastic rheology, for stresses in a wedge on the verge of Coulomb failure there must co-exist a critical taper solution involving μ and a unique equivalent elastic solution not involving μ . Our elastic solution precisely reduces to Dahlen's critical taper solution for critical conditions. For stable conditions, normal stress perpendicular to the surface slope σ z and shear stress τ xz are identical with those in a critical taper, but the slope-parallel normal stress is different. The elastic solution is also generally applicable to purely elastic wedges and useful for modeling geodetic observations. A stable noncohesive Coulomb wedge differs from a general elastic wedge in that its upper and lower surfaces stay at zero curvature during loading. Dahlen, F.A. (1984), Noncohesive critical Coulomb wedges: An exact solution, JGR, 89, 10,125-10,133.
Limpanuparb, Taweetham; Milthorpe, Josh; Rendell, Alistair P
2014-10-30
Use of the modern parallel programming language X10 for computing long-range Coulomb and exchange interactions is presented. By using X10, a partitioned global address space language with support for task parallelism and the explicit representation of data locality, the resolution of the Ewald operator can be parallelized in a straightforward manner including use of both intranode and internode parallelism. We evaluate four different schemes for dynamic load balancing of integral calculation using X10's work stealing runtime, and report performance results for long-range HF energy calculation of large molecule/high quality basis running on up to 1024 cores of a high performance cluster machine.
Yarimizu, Tohru; Nonklang, Sanom; Nakamura, Junpei; Tokuda, Shuya; Nakagawa, Takaaki; Lorreungsil, Sasithorn; Sutthikhumpha, Surasit; Pukahuta, Charida; Kitagawa, Takao; Nakamura, Mikiko; Cha-Aim, Kamonchai; Limtong, Savitree; Hoshida, Hisashi; Akada, Rinji
2013-12-01
The isolation and application of auxotrophic mutants for gene manipulations, such as genetic transformation, mating selection and tetrad analysis, form the basis of yeast genetics. For the development of these genetic methods in the thermotolerant fermentative yeast Kluyveromyces marxianus, we isolated a series of auxotrophic mutants with defects in amino acid or nucleic acid metabolism. To identify the mutated genes, linear DNA fragments of nutrient biosynthetic pathway genes were amplified from Saccharomyces cerevisiae chromosomal DNA and used to directly transform the K. marxianus auxotrophic mutants by random integration into chromosomes through non-homologous end joining (NHEJ). The appearance of transformant colonies indicated that the specific S. cerevisiae gene complemented the K. marxianus mutant. Using this interspecific complementation approach with linear PCR-amplified DNA, we identified auxotrophic mutations of ADE2, ADE5,7, ADE6, HIS2, HIS3, HIS4, HIS5, HIS6, HIS7, LYS1, LYS2, LYS4, LYS9, LEU1, LEU2, MET2, MET6, MET17, TRP3, TRP4 and TRP5 without the labour-intensive requirement of plasmid construction. Mating, sporulation and tetrad analysis techniques for K. marxianus were also established. With the identified auxotrophic mutant strains and S. cerevisiae genes as selective markers, NHEJ-mediated integrative transformation with PCR-amplified DNA is an attractive system for facilitating genetic analyses in the yeast K. marxianus.
The Funk transform as a Penrose transform
NASA Astrophysics Data System (ADS)
Bailey, Toby N.; Eastwood, Michael G.; Gover, A. Rod; Mason, Lionel J.
1999-01-01
The Funk transform is the integral transform from the space of smooth even functions on the unit sphere S2[subset or is implied by][open face R]3 to itself defined by integration over great circles. One can regard this transform as a limit in a certain sense of the Penrose transform from [open face C][open face P]2 to [open face C][open face P]*ast;2. We exploit this viewpoint by developing a new proof of the bijectivity of the Funk transform which proceeds by considering the cohomology of a certain involutive (or formally integrable) structure on an intermediate space. This is the simplest example of what we hope will prove to be a general method of obtaining results in real integral geometry by means of complex holomorphic methods derived from the Penrose transform.
PFLOW: A 3-D Numerical Modeling Tool for Calculating Fluid-Pressure Diffusion from Coulomb Strain
NASA Astrophysics Data System (ADS)
Wolf, L. W.; Lee, M.; Meir, A.; Dyer, G.; Ma, K.; Chan, C.
2009-12-01
A new 3D time-dependent pore-pressure diffusion model PFLOW is developed to investigate the response of pore fluids to the crustal deformation generated by strong earthquakes in heterogeneous geologic media. Given crustal strain generated by changes in Coulomb stress, this MATLAB-based code uses Skempton's coefficient to calculate resulting changes fluid pressure. Pore-pressure diffusion can be tracked over time in a user-defined model space with user-prescribed Neumann or Dirchilet boundary conditions and with spatially variable values of permeability. PFLOW employs linear or quadratic finite elements for spatial discretization and first order or second order, explicit or implicit finite difference discretization in time. PFLOW is easily interfaced with output from deformation modeling programs such as Coulomb (Toda et al., 2007) or 3D-DEF (Gomberg and Ellis, 1994). The code is useful for investigating to first-order the evolution of pore pressure changes induced by changes in Coulomb stress and their possible relation to water-level changes in wells or changes in stream discharge. It can also be used for student research and classroom instruction. As an example application, we calculate the coseismic pore pressure changes and diffusion induced by volumetric strain associated with the 1999 Chi-Chi earthquake (Mw = 7.6) in Taiwan. The Chi-Chi earthquake provides an unique opportunity to investigate the spatial and time-dependent poroelastic response of near-field rocks and sediments because there exist extensive observational data of water-level changes and crustal deformation. The integrated model allows us to explore whether changes in Coulomb stress can adequately explain hydrologic anomalies observed in areas such as Taiwan’s western foothills and the Choshui River alluvial plain. To calculate coseismic strain, we use the carefully calibrated finite fault-rupture model of Ma et al. (2005) and the deformation modeling code Coulomb 3.1 (Toda et al., 2007
Thermodynamic functions of the hcp Coulomb crystal lattice
NASA Astrophysics Data System (ADS)
Kozhberov, A. A.; Baiko, D. A.
2015-10-01
One-component Coulomb crystals of ions with hexagonal close-packed (hcp) lattice likely form in the crust of strongly-magnetized neutron stars (magnetars). In this work we present a detailed study of vibration modes and thermodynamic properties of such crystals in a wide range of temperatures at zero magnetic field. In contrast to typically considered lattices, the phonon spectrum of the system exhibits a peculiar crossing of the acoustic modes near the Brillouin zone center in certain directions of the wavevector. It is demonstrated that in the field-free regime the Helmholtz free energy of the hcp Coulomb crystal is always higher than those of the Coulomb crystals with body-centered cubic and face-centered cubic lattices. The results of our numerical calculations are fitted by simple analytic expressions.
Coulomb matrix elements in multi-orbital Hubbard models
NASA Astrophysics Data System (ADS)
Bünemann, Jörg; Gebhard, Florian
2017-04-01
Coulomb matrix elements are needed in all studies in solid-state theory that are based on Hubbard-type multi-orbital models. Due to symmetries, the matrix elements are not independent. We determine a set of independent Coulomb parameters for a d-shell and an f-shell and all point groups with up to 16 elements (O h , O, T d , T h , D 6h , and D 4h ). Furthermore, we express all other matrix elements as a function of the independent Coulomb parameters. Apart from the solution of the general point-group problem we investigate in detail the spherical approximation and first-order corrections to the spherical approximation.
Coulomb explosion of the hot spot of micropinches
NASA Astrophysics Data System (ADS)
Oreshkin, V. I.; Oreshkin, E. V.
2017-01-01
It has been shown that the generation of hard X-ray radiation, electron beam, and high energy ions that have been detected in experiments on compressing pinches can be related to the Coulomb explosion of a micropinch hot spot, which is formed due to the outflow of the material. In the outflow process, the plasma temperature in the hot spot increases and conditions appear for the transition of electrons to the regime of continuous acceleration. The exit of runaway electrons from the hot spot region leads to the creation of a positive bulk charge, then to a Coulomb explosion. Conditions under which electrons pass to the continuous acceleration regime have been determined and estimates of the ion kinetic energy upon a Coulomb explosion have been obtained.
Gribov horizon and Gribov copies effect in lattice Coulomb gauge
NASA Astrophysics Data System (ADS)
Burgio, Giuseppe; Quandt, Markus; Reinhardt, Hugo; Vogt, Hannes
2017-01-01
Following a recent proposal by Cooper and Zwanziger, we investigate via S U (2 ) lattice simulations the effect on the Coulomb gauge propagators and on the Gribov-Zwanziger confinement mechanism of selecting the Gribov copy with the smallest nontrivial eigenvalue of the Faddeev-Popov operator, i.e., the one closest to the Gribov horizon. Although such choice of gauge drives the ghost propagator towards the prediction of continuum calculations, we find that it actually overshoots the goal. With increasing computer time, we observe that Gribov copies with arbitrarily small eigenvalues can be found. For such a method to work, one would therefore need further restrictions on the gauge condition to isolate the physically relevant copies, since, for example, the Coulomb potential VC defined through the Faddeev-Popov operator becomes otherwise physically meaningless. Interestingly, the Coulomb potential alternatively defined through temporal link correlators is only marginally affected by the smallness of the eigenvalues.
Coulomb branch Hilbert series and Hall-Littlewood polynomials
NASA Astrophysics Data System (ADS)
Cremonesi, Stefano; Hanany, Amihay; Mekareeya, Noppadol; Zaffaroni, Alberto
2014-09-01
There has been a recent progress in understanding the chiral ring of 3d = 4 superconformal gauge theories by explicitly constructing an exact generating function (Hilbert series) counting BPS operators on the Coulomb branch. In this paper we introduce Coulomb branch Hilbert series in the presence of background magnetic charges for flavor symmetries, which are useful for computing the Hilbert series of more general theories through gluing techniques. We find a simple formula of the Hilbert series with background magnetic charges for T ρ ( G) theories in terms of Hall-Littlewood polynomials. Here G is a classical group and ρ is a certain partition related to the dual group of G. The Hilbert series for vanishing background magnetic charges show that Coulomb branches of T ρ ( G) theories are complete intersections. We also demonstrate that mirror symmetry maps background magnetic charges to baryonic charges.
Effect of Coulombic friction on spatial displacement statistics.
Menzel, Andreas M; Goldenfeld, Nigel
2011-07-01
The phenomenon of Coulombic friction enters the stochastic description of dry friction between two solids and the statistic characterization of vibrating granular media. Here we analyze the corresponding Fokker-Planck equation including both velocity and spatial components, exhibiting a formal connection to a quantum mechanical harmonic oscillator in the presence of a delta potential. Numerical solutions for the resulting spatial displacement statistics show a crossover from exponential to Gaussian displacement statistics. We identify a transient intermediate regime that exhibits multiscaling properties arising from the contribution of Coulombic friction. The possible role of these effects during observations in diffusion experiments is briefly discussed.
Separable wave equation for three Coulomb interacting particles
NASA Astrophysics Data System (ADS)
Colavecchia, F. D.; Gasaneo, G.; Garibotti, C. R.
1998-02-01
We consider a separable approximation to the Schrödinger equation for the three-body Coulomb problem and found its exact solution above the ionization threshold. This wave function accounts for different possible asymptotic behaviors and reduces to the well-known product of three two-body Coulomb waves (C3) for scattering conditions. The momenta and position-dependent modifications recently proposed for the Sommerfeld parameters, as an improvement to the C3 model, are analyzed. We show how these changes can be included in our model as a suitable physically based variations in the separable approximation for the wave equation.
On rate-state and Coulomb failure models
Gomberg, J.; Beeler, N.; Blanpied, M.
2000-01-01
We examine the predictions of Coulomb failure stress and rate-state frictional models. We study the change in failure time (clock advance) Δt due to stress step perturbations (i.e., coseismic static stress increases) added to "background" stressing at a constant rate (i.e., tectonic loading) at time t0. The predictability of Δt implies a predictable change in seismicity rate r(t)/r0, testable using earthquake catalogs, where r0 is the constant rate resulting from tectonic stressing. Models of r(t)/r0, consistent with general properties of aftershock sequences, must predict an Omori law seismicity decay rate, a sequence duration that is less than a few percent of the mainshock cycle time and a return directly to the background rate. A Coulomb model requires that a fault remains locked during loading, that failure occur instantaneously, and that Δt is independent of t0. These characteristics imply an instantaneous infinite seismicity rate increase of zero duration. Numerical calculations of r(t)/r0 for different state evolution laws show that aftershocks occur on faults extremely close to failure at the mainshock origin time, that these faults must be "Coulomb-like," and that the slip evolution law can be precluded. Real aftershock population characteristics also may constrain rate-state constitutive parameters; a may be lower than laboratory values, the stiffness may be high, and/or normal stress may be lower than lithostatic. We also compare Coulomb and rate-state models theoretically. Rate-state model fault behavior becomes more Coulomb-like as constitutive parameter a decreases relative to parameter b. This is because the slip initially decelerates, representing an initial healing of fault contacts. The deceleration is more pronounced for smaller a, more closely simulating a locked fault. Even when the rate-state Δt has Coulomb characteristics, its magnitude may differ by some constant dependent on b. In this case, a rate-state model behaves like a modified
Higher-order dynamical effects in Coulomb dissociation
Esbensen, H.; Bertsch, G.F.; Bertulani, C.A.
1995-08-01
Coulomb dissociation is a technique commonly used to extract the dipole response of nuclei far from stability. This technique is applicable if the dissociation is dominated by dipole transitions and if first-order perturbation theory is valid. In order to assess the significance of higher-order processes we solve numerically the time evolution of the wave function for a two-body breakup in the Coulomb field from a high Z target. We applied this method to the breakup reactions: {sup 11}Be {yields} {sup 10}Be + n and {sup 11}Li {yields} +2n. The latter is treated as a two-body breakup, using a di-neutron model.
Running Coulomb potential and Lamb shift in QCD
Hoang, Andre H.; Manohar, Aneesh V.; Stewart, Iain W.
2001-07-01
The QCD {beta} function and the anomalous dimensions for the Coulomb potential and the static potential first differ at three loop order. We evaluate the three loop ultrasoft anomalous dimension for the Coulomb potential and give the complete three loop running. Using this result, we calculate the leading logarithmic Lamb shift for a heavy-quark{endash}antiquark bound state, which includes all contributions to the binding energies of the form m{alpha}{sub s}{sup 4}({alpha}{sub s}ln{alpha}{sub s}){sup k}, k{ge}0.
Kit, S; Hazen, M; Otsuka, H; Qavi, H; Trkula, D; Dubbs, D R
1981-12-01
To analyze the site of integration of the herpes simplex virus type I (HSV-I) thymidine kinase (TK) gene in biochemically transformed human cells, TK-HeLa-(BU25) cells were transformed to the TK+ phenotype by a cloned, 2 kbp Pvull fragment of HSV-I DNA. The transformed cells [HeLa(BU25)/TF pAGO PP3] were fused with mouse LM(TK-) cells, and human-mouse somatic cell hybrid clones (LH PP3 clones 1, 2, 3, 5 and 6) were isolated in HATG-ouabain selective medium. The HeLa(BU25)/TF pAGO PP3 cells and the LH PP3 hybrid clones expressed HSV-I specific TK activity and a herpesvirus-associated nuclear antigen, and contained herpesvirus nucleotide sequences. Molecular hybridization experiments were carried out to map the HSV-I and flanking cellular nucleotide sequences in the biochemically transformed cells. These experiments demonstrated that the HSV-I nucleotide sequences were integrated at a single site, and that the same cellular nucleotide sequences flanked the viral DNA in transformed HeLa(BU25)/TF pAGO PP3 and LH PP3 clone 5 cells. TK- revertant subclones isolated by growing the LH PP3 clone 5 cells in BrdUrd (and diphtheria toxin) failed to form colonies in HATG medium, but retained HSV-I nucleotide sequences. Isozyme analyses on 21 gene-enzyme systems representing 21 human chromosomes revealed that all of the LH PP3 clonal lines expressed human hexosaminidase B, which has been assigned to chromosome 5, and all were sensitive to diphtheria toxin, which is also a marker for chromosome 5. Chromosome analyses showed that chromosome 5 was the nly human chromosome present in mitoses of LH PP3 clone 5 cells and that human chromosome 5 was present in most of the mitoses of LH PP3 clone 1, 2, 3, and 6 cells. The latter clones also contained 1 or 2 additional human chromosomes in some of the cells. As expected from the molecular hybridization analyses, TK- revertants of LH PP3 clone 5 cells retained portions of chromosome 5 and expressed human hexosaminidase B. The results
Amplitude Function of Asymptotic Correlations Along Charged Wall in Coulomb Fluids
NASA Astrophysics Data System (ADS)
Šamaj, Ladislav
2016-07-01
In classical semi-infinite Coulomb fluids, two-point correlation functions exhibit a slow inverse-power law decay along a uniformly charged wall. In this work, we concentrate on the corresponding amplitude function which depends on the distances of the two points from the wall. Recently Šamaj (J Stat Phys 161:227-249 2015), applying a technique of anticommuting variables to a 2D system of charged rectilinear wall with "counter-ions only", we derived a relation between the amplitude function and the density profile which holds for any temperature. In this paper, using the Möbius conformal transformation of particle coordinates in a disc, a new relation between the amplitude function and the density profile is found for that model. In all exactly solvable cases, the amplitude function factorizes itself in the two distances from the wall. Presupposing this factorization property at any temperature and using specific sum rules for semi-infinite geometries, a relation between the amplitude function of the charge-charge structure function and the charge profile is derived for many-component Coulomb fluids in any dimension.
Isotope shifts and coulomb displacement energies in calcium isotopes
NASA Astrophysics Data System (ADS)
Caurier, E.; Poves, A.; Zuker, A.
1980-10-01
Isotope shifts, neutron-proton radii differences and Coulomb displacement energies are calculated for calcium isotopes A = 41 to 48. A simple parametrization of the core polarization terms of the effective force in the framework of the Isospin Projected Hartree-Fock (IPHF) method leads to good agreement between theory and experiment.
Coulomb repulsion and the electron beam directed energy weapon
NASA Astrophysics Data System (ADS)
Retsky, Michael W.
2004-09-01
Mutual repulsion of discrete charged particles or Coulomb repulsion is widely considered to be an ultimate hard limit in charged particle optics. It prevents the ability to finely focus high current beams into small spots at large distances from defining apertures. A classic example is the 1970s era "Star Wars" study of an electron beam directed energy weapon as an orbiting antiballistic missile device. After much analysis, it was considered physically impossible to focus a 1000-amp 1-GeV beam into a 1-cm diameter spot 1000-km from the beam generator. The main reason was that a 1-cm diameter beam would spread to 5-m diameter at 1000-km due to Coulomb repulsion. Since this could not be overcome, the idea was abandoned. But is this true? What if the rays were reversed? That is, start with a 5-m beam converging slightly with the same nonuniform angular and energy distribution as the electrons from the original problem were spreading at 1000-km distance. Could Coulomb repulsion be overcome? Looking at the terms in computational studies, some are reversible while others are not. Based on estimates, the nonreversible terms should be small - of the order of 0.1 mm. If this is true, it is possible to design a practical electron beam directed weapon not limited by Coulomb repulsion.
Limits to Electron Beam Emittance from Stochastic Coulomb Interactions
Coleman-Smith, Christopher; Padmore, Howard A.; Wan, Weishi
2008-08-22
Dense electron beams can now be generated on an ultrafast timescale using laser driven photo-cathodes and these are used for a range of applications from ultrafast electron defraction to free electron lasers. Here we determine a lower bound to the emittance of an electron beam limited by fundamental stochastic Coulomb interactions.
Exchange Coulomb interaction in nanotubes: Dispersion of Langmuir waves
Andreev, P. A. Ivanov, A. Yu.
2015-07-15
The microscopic derivation of the Coulomb exchange interaction for electrons located on the nanotubes is presented. The derivation is based on the many-particle quantum hydrodynamic method. We demonstrate the effect of curvature of the nanocylinders on the force of exchange interaction. We calculate corresponding dispersion dependencies for electron oscillations on the nanotubes.
Coulomb Interactions in Hanbury Brown-Twiss Experiments with Electrons
ERIC Educational Resources Information Center
Shen, Kan
2009-01-01
This dissertation examines the effect of Coulomb interactions in Hanbury Brown-Twiss (HBT) type experiments with electrons. HBT experiments deal with intensity interference, which is related to the second-order correlation function of the particle field. This is an extension of the usual amplitude interference experiment, such as Young's…
Coulomb gauge approach for charmonium meson and hybrid radiative transitions
Gou, Peng; Yepez-Martínez, Tochtli; Szczepaniak, Adam P.
2015-01-22
We consider the lowest order interaction of the Foldy-Wouthuysen QED and QCD Hamiltonian in the Coulomb gauge approach, to describe radiative transitions between conventional and hybrids charmonium mesons. The results are compared to potential quark models and lattices calculations.
Accurate Coulomb blockade thermometry up to 60 kelvin.
Meschke, M; Kemppinen, A; Pekola, J P
2016-03-28
We demonstrate experimentally a precise realization of Coulomb blockade thermometry working at temperatures up to 60 K. Advances in nano-fabrication methods using electron beam lithography allow us to fabricate uniform arrays of sufficiently small tunnel junctions to guarantee an overall temperature reading precision of about 1%.
Existence of the thermodynamic limit for disordered quantum Coulomb systems
NASA Astrophysics Data System (ADS)
Blanc, Xavier; Lewin, Mathieu
2012-09-01
Following a recent method introduced by Hainzl, Solovej, and Lewin, we prove the existence of the thermodynamic limit for a system made of quantum electrons, and classical nuclei whose positions and charges are randomly perturbed in an ergodic fashion. All the particles interact through Coulomb forces.
Interpolating the Coulomb phase of little string theory
Lin, Ying -Hsuan; Shao, Shu -Heng; Wang, Yifan; ...
2015-12-03
We study up to 8-derivative terms in the Coulomb branch effective action of (1,1) little string theory, by collecting results of 4-gluon scattering amplitudes from both perturbative 6D super-Yang-Mills theory up to 4-loop order, and tree-level double scaled little string theory (DSLST). In previous work we have matched the 6-derivative term from the 6D gauge theory to DSLST, indicating that this term is protected on the entire Coulomb branch. The 8-derivative term, on the other hand, is unprotected. In this paper we compute the 8-derivative term by interpolating from the two limits, near the origin and near the infinity onmore » the Coulomb branch, numerically from SU(k) SYM and DSLST respectively, for k=2,3,4,5. We discuss the implication of this result on the UV completion of 6D SYM as well as the strong coupling completion of DSLST. As a result, we also comment on analogous interpolating functions in the Coulomb phase of circle-compactified (2,0) little string theory.« less
Finiteness of the Coulomb gauge QCD perturbative effective action
Andraši, A.; Taylor, J.C.
2015-05-15
At 2-loop order in the Coulomb gauge, individual Feynman graphs contributing to the effective action have energy divergences. It is proved that these cancel in suitable combinations of graphs. This has previously been shown only for transverse external fields. The calculation results in a generalization of the Christ–Lee term which was inserted into the Hamiltonian.
Application of Designer Polynomials to the Soft-Coulomb Potential
NASA Astrophysics Data System (ADS)
Weatherford, Charles; Wynn, Albert, III; Red, Eddie; Mathis, Clausell
2004-05-01
In a recent article [C.A. Weatherford, E. Red, A. Wynn III, International Journal of Quantum Chemistry 90, 1289-1294 (2002)], an algorithm was described whereby a synthetic weighted polynomial basis may be constructed which is adapted (designed) to a particular potential. It was applied therein to the Schroedinger equation with a coulomb potential in one dimension (-1/|x| ). A weighted polynomial basis with weight function w(x)=exp(-a|x|) was employed. It was observed that this potential had no even parity solutions - only odd parity solutions. The question arises as to the relationship of the solutions (eigenfunctions and eigenvalues) for this hard coulomb potential to the solutions for the soft coulomb potential (-1/ √x^2+b^2^1/2 ). In particular, since the soft coulomb potential is clearly expected to possess both even and odd parity solutions, how do these solutions behave as b->0 and thus what happens to the even solutions. This problem is deceptively difficult none of the standard basis sets produce a variational minimum as a function of 'a' for nonzero 'b'. This is apparently why this problem has never been done before. A new orthonormal basis was designed with weight function w(x)=exp(-a√x^2+b^2) which did produce a variational minimum for variable a and arbitrary fixed 'b'. The present paper describes these solutions and clearly indicates how they behave as b->0 .
Hamiltonian flow in Coulomb gauge Yang-Mills theory
Leder, Markus; Reinhardt, Hugo; Pawlowski, Jan M.; Weber, Axel
2011-01-15
We derive a new functional renormalization group equation for Hamiltonian Yang-Mills theory in Coulomb gauge. The flow equations for the static gluon and ghost propagators are solved under the assumption of ghost dominance within different diagrammatic approximations. The results are compared to those obtained in the variational approach and the reliability of the approximations is discussed.
Interpolating the Coulomb phase of little string theory
Lin, Ying -Hsuan; Shao, Shu -Heng; Wang, Yifan; Yin, Xi
2015-12-03
We study up to 8-derivative terms in the Coulomb branch effective action of (1,1) little string theory, by collecting results of 4-gluon scattering amplitudes from both perturbative 6D super-Yang-Mills theory up to 4-loop order, and tree-level double scaled little string theory (DSLST). In previous work we have matched the 6-derivative term from the 6D gauge theory to DSLST, indicating that this term is protected on the entire Coulomb branch. The 8-derivative term, on the other hand, is unprotected. In this paper we compute the 8-derivative term by interpolating from the two limits, near the origin and near the infinity on the Coulomb branch, numerically from SU(k) SYM and DSLST respectively, for k=2,3,4,5. We discuss the implication of this result on the UV completion of 6D SYM as well as the strong coupling completion of DSLST. As a result, we also comment on analogous interpolating functions in the Coulomb phase of circle-compactified (2,0) little string theory.
Luo, H; Hu, Q; Nelson, K; Longo, C; Kausch, A P; Chandlee, J M; Wipff, J K; Fricker, C R
2004-04-01
Genetic transformation of creeping bentgrass mediated by Agrobacterium tumefaciens has been achieved. Embryogenic callus initiated from seeds (cv. Penn-A-4) was infected with an A. tumefaciens strain (LBA4404) harboring a super-binary vector that contained an herbicide-resistant bar gene driven either by the CaMV 35S promoter or a rice ubiquitin promoter. Plants were regenerated from 219 independent transformation events. The overall stable transformation efficiency ranged from 18% to 45%. Southern blot and genetic analysis confirmed transgene integration in the creeping bentgrass genome and normal transmission and stable expression of the transgene in the T1 generation. All independent transformation events carried one to three copies of the transgene, and a majority (60-65%) contained only a single copy of the foreign gene with no apparent rearrangements. We report here the successful use of Agrobacterium for the large-scale production of transgenic creeping bentgrass plants with a high frequency of a single-copy transgene insertion that exhibit stable inheritance patterns.
Ibrahim, Ahmed; Bucur, Anca; Perez-Rey, David; Alonso, Enrique; de Hoog, Matthy; Dekker, Andre; Marshall, M Scott
2015-01-01
This paper describes the data transformation pipeline defined to support the integration of a new clinical site in a standards-based semantic interoperability environment. The available datasets combined structured and free-text patient data in Dutch, collected in the context of radiation therapy in several cancer types. Our approach aims at both efficiency and data quality. We combine custom-developed scripts, standard tools and manual validation by clinical and knowledge experts. We identified key challenges emerging from the several sources of heterogeneity in our case study (systems, language, data structure, clinical domain) and implemented solutions that we will further generalize for the integration of new sites. We conclude that the required effort for data transformation is manageable which supports the feasibility of our semantic interoperability solution. The achieved semantic interoperability will be leveraged for the deployment and evaluation at the clinical site of applications enabling secondary use of care data for research. This work has been funded by the European Commission through the INTEGRATE (FP7-ICT-2009-6-270253) and EURECA (FP7-ICT-2011-288048) projects.
Ibrahim, Ahmed; Bucur, Anca; Perez-Rey, David; Alonso, Enrique; de Hoog, Matthy; Dekker, Andre; Marshall, M. Scott
2015-01-01
This paper describes the data transformation pipeline defined to support the integration of a new clinical site in a standards-based semantic interoperability environment. The available datasets combined structured and free-text patient data in Dutch, collected in the context of radiation therapy in several cancer types. Our approach aims at both efficiency and data quality. We combine custom-developed scripts, standard tools and manual validation by clinical and knowledge experts. We identified key challenges emerging from the several sources of heterogeneity in our case study (systems, language, data structure, clinical domain) and implemented solutions that we will further generalize for the integration of new sites. We conclude that the required effort for data transformation is manageable which supports the feasibility of our semantic interoperability solution. The achieved semantic interoperability will be leveraged for the deployment and evaluation at the clinical site of applications enabling secondary use of care data for research. This work has been funded by the European Commission through the INTEGRATE (FP7-ICT-2009-6-270253) and EURECA (FP7-ICT-2011-288048) projects. PMID:26306242
Unuofin, F O; Siswana, M; Cishe, E N
2016-01-01
Rock phosphate (RP) addition in cow-dung waste-paper mixtures at rates above 2% P has been reported to increase the rate of bio-transformation and humification of organic waste mixtures during vermicomposting to produce organic fertilizer for organic farming. However, the optimization of RP for vermicomposting was not established. The objective of this study was to determine the optimal amount of RP integration rates for effective bio-transformation of cow-dung waste-paper mixtures. Arrays of RP integration degrees (0, 0.5, 1, 1.5, 2, and 4% P as RP) were thoroughly mixed with cow- dung waste-paper mixtures to achieve an optimized C:N ratio of 30 and allowed to vermidegrade following the introduction of earthworms at a stocking mass of 12.5 g-worms kg(-1). The bio-transformation of the waste mixtures was examined by measuring C:N ratios and humification index (HI) and per cent ash and volatile solids. Application of 1% P as RP resulted in fast bio-transformation and maturation of cow-dung waste-paper mixtures. A scanning electron microscopy (SEM) was used to evaluate the morphological properties of the different vermicomposts affected by rates of RP showing the degree of degradation of initial compacted aggregates of cellulose and protein fibres in the mixtures at maturity. A germination test was used to further determine phytotoxicity of the final composts and microbial biomass assessment. The final vermicompost (organic fertilizer) had a C:N ratio of 7, MBC of 900 mg kg(-1) and HI of 27.1%. The RP incorporation rate of 1% P of RP investigated is therefore, recommended for efficient vermidegradation and humification of cow-dung waste-paper mixtures. However, higher rates of RP incorporation should be considered where greater P enrichment of the final vermicompost (organic fertilizer) is desired.
Compact Collision Kernels for Hard Sphere and Coulomb Cross Sections; Fokker-Planck Coefficients
Chang Yongbin; Shizgal, Bernie D.
2008-12-31
A compact collision kernel is derived for both hard sphere and Coulomb cross sections. The difference between hard sphere interaction and Coulomb interaction is characterized by a parameter {eta}. With this compact collision kernel, the calculation of Fokker-Planck coefficients can be done for both the Coulomb and hard sphere interactions. The results for arbitrary order Fokker-Planck coefficients are greatly simplified. An alternate form for the Coulomb logarithm is derived with concern to the temperature relaxation in a binary plasma.
Small-angle Coulomb collision model for particle-in-cell simulations
Lemons, Don S. Winske, Dan; Daughton, William; Albright, Brian
2009-03-20
We construct and investigate a set of stochastic differential equations that incorporate the physics of velocity-dependent small-angle Coulomb collisions among the plasma particles in a particle-in-cell simulation. Each particle is scattered stochastically from all the other particles in a simulation cell modeled as one or more Maxwellians. Total energy and momentum are conserved by linear transformation of the velocity increments. In two test simulations the proposed 'particle-moment' collision algorithm performs well with time steps as large as 10% of the relaxation time - far larger than a particle-pairing collision algorithm, in which pairs of particles are scattered from one another, requires to achieve the same accuracy.
Transformational Learners: Transformational Teachers
ERIC Educational Resources Information Center
Jones, Marguerite
2009-01-01
Transformational learning, according to Mezirow (1981), involves transforming taken-for-granted frames of reference into more discriminating, flexible "habits of mind". In teacher education, transformative learning impacts on the development of students' action theories, self-efficacy and professional attributes. Although considered…
NASA Astrophysics Data System (ADS)
Glaeske, H.-J.; Kilbas, Anatoly A.; Saigo, Megumi
2000-06-01
The paper is devoted to study the integral transformwith the kernelfor [beta]>0; Re([gamma])>1/[beta]-1; ; Re(z)>0, which is a generalization of the modified Bessel function of the third kind or Macdonald function K-[gamma](z). Properties of [lambda][gamma],[sigma]([beta])(z) are investigated and compositions of the operator L[gamma],[sigma]([beta]) with the left- and right-sided Liouville fractional integrals and derivatives are proved.
The Effects of Static Coulomb Stress Change on Southern California Earthquake Forecasting
NASA Astrophysics Data System (ADS)
Strader, Anne Elizabeth
I investigate how inclusion of static Coulomb stress changes, caused by tectonic loading and previous seismicity, contributes to the effectiveness and reliability of prospective earthquake forecasts. Several studies have shown that positive static Coulomb stress changes are associated with increased seismicity, relative to stress shadows. However, it is difficult to avoid bias when the learning and testing intervals are chosen retrospectively. I hypothesize that earthquake forecasts based on static Coulomb stress fields may improve upon existing earthquake forecasts based on historical seismicity. Within southern California, I have confirmed the aforementioned relationship between earthquake location and Coulomb stress change, but found no identifiable triggering threshold based on static Coulomb stress history at individual earthquake locations. I have also converted static Coulomb stress changes into spatially-varying earthquake rates by optimizing an index function and calculating probabilities of cells containing at least one earthquake based on Coulomb stress ranges. Inclusion of Coulomb stress effects gives an improvement in earthquake forecasts that is significant with 95% confidence, compared to smoothed seismicity null forecasts. Because of large uncertainties in Coulomb stress calculations near faults (and aftershock distributions), I combine static Coulomb stress and smoothed seismicity into a hybrid earthquake forecast. Evaluating such forecasts against those in which only Coulomb stress or smoothed seismicity determines earthquake rates indicates that Coulomb stress is more effective in the far field, whereas statistical seismology outperforms Coulomb stress near faults. Additionally, I test effects of receiver plane orientation, stress type (normal and shear components), and declustering receiver earthquakes. While static Coulomb stress shows significant potential in a prospective earthquake forecast, simplifying assumptions compromise its
Conductance of a proximitized nanowire in the Coulomb blockade regime
NASA Astrophysics Data System (ADS)
van Heck, B.; Lutchyn, R. M.; Glazman, L. I.
2016-06-01
We identify the leading processes of electron transport across finite-length segments of proximitized nanowires and build a quantitative theory of their two-terminal conductance. In the presence of spin-orbit interaction, a nanowire can be tuned across the topological transition point by an applied magnetic field. Due to a finite segment length, electron transport is controlled by the Coulomb blockade. Upon increasing of the field, the shape and magnitude of the Coulomb blockade peaks in the linear conductance are defined, respectively, by Andreev reflection, single-electron tunneling, and resonant tunneling through the Majorana modes emerging after the topological transition. Our theory provides the framework for the analysis of experiments with proximitized nanowires [such as reported in S. M. Albrecht et al., Nature (London) 531, 206 (2016), 10.1038/nature17162] and identifies the signatures of the topological transition in the two-terminal conductance.
Coulomb and electron-phonon interactions in metals
NASA Astrophysics Data System (ADS)
Tupitsyn, Igor S.; Mishchenko, Andrey S.; Nagaosa, Naoto; Prokof'ev, Nikolay
2016-10-01
An accurate and consistent theory of phonons in metals requires that all long-range Coulomb interactions between charged particles (electrons and ions) be treated on equal footing. So far, all attempts to deal with this nonperturbative system were relying on uncontrolled approximations in the absence of small parameters. In this paper, we develop the diagrammatic Monte Carlo approach for a two-component Coulomb system that obtains the solution to this fundamental problem in an approximation-free way by computing vertex corrections from higher-order skeleton graphs. The feasibility of the method is demonstrated by calculating the spectrum of longitudinal acoustic phonons in a simple cubic lattice, determining their sound velocity, and obtaining the phonon spectral densities by analytic continuation of the Matsubara-Green's functions. Final results are checked against the lowest-order fully self-consistent G W approximation in both adiabatic and nonadiabatic regimes.
Electronic cooling via interlayer Coulomb coupling in multilayer epitaxial graphene.
Mihnev, Momchil T; Tolsma, John R; Divin, Charles J; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A; MacDonald, Allan H; Norris, Theodore B
2015-09-24
In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron-phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport, even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier dynamics as temperature and the number of layers is varied.
Coulomb effects in low-energy nuclear fragmentation
NASA Technical Reports Server (NTRS)
Wilson, John W.; Chun, Sang Y.; Badavi, Francis F.; John, Sarah
1993-01-01
Early versions of the Langley nuclear fragmentation code NUCFRAG (and a publicly released version called HZEFRG1) assumed straight-line trajectories throughout the interaction. As a consequence, NUCFRAG and HZEFRG1 give unrealistic cross sections for large mass removal from the projectile and target at low energies. A correction for the distortion of the trajectory by the nuclear Coulomb fields is used to derive fragmentation cross sections. A simple energy-loss term is applied to estimate the energy downshifts that greatly alter the Coulomb trajectory at low energy. The results, which are far more realistic than prior versions of the code, should provide the data base for future transport calculations. The systematic behavior of charge-removal cross sections compares favorably with results from low-energy experiments.
Proton focusing driven by laser triggered Coulomb explosion
NASA Astrophysics Data System (ADS)
Wang, W. Q.; Yin, Y.; Zou, D. B.; Yu, T. P.; Ge, Z. Y.; Xu, H.; Zhuo, H. B.; Shao, F. Q.
2017-03-01
A mechanism of the acceleration and focusing of quasi-monoenergetic proton beams from a thin arched carbon-hydrogen target irradiated by a relativistic-intensity laser pulse is investigated by multi-dimensional particle-in-cell (PIC) simulations. As an intense linearly polarized laser pulse impinges on the thin target, a considerable number of electrons are evacuated, leading to Coulomb explosion in the excess positive charges left behind. Accompanying with the acceleration, the protons are focused ballistically in the Coulomb field, which is mainly contributed by the carbon ions. It is demonstrated that a quasi-monoenergetic proton bunch with the energy-density as high as 1017 J/m3 is produced by using a laser pulse with the intensity of 1021 W/cm2. An analytical model is proposed to predict the proton energy and the focal position, which is fairly consistent with PIC simulations.
Role of the Permanent Dipole Moment in Coulomb Explosion
NASA Astrophysics Data System (ADS)
Zhang, Cai-Ping; Miao, Xiang-Yang
2013-10-01
By numerically solving the non-Born—Oppenheimer time-dependent Schrödinger equation in a few-cycle chirped laser field (5-fs, 800-nm), the effect of the permanent dipole moment on the Coulomb explosion is studied by the kinetic-energy-release spectra with the “virtual detector" method. The results indicate that with the effect of the permanent dipole moment, different multiphoton processes for heteronuclear and homonuclear diatomic molecular ions may take place when the wave packets transit from the ground state (1sσg) to the first excited state (2pσu), and then move along the excited potential curve, and finally charge-resonant enhanced ionization occurs at critical internuclear distance. As a result, despite the similar ionization probabilities for these two systems at higher vibrational level with larger chirp parameter β, the structure of the Coulomb explosion spectrum for the former is prominently different from that for the latter.
Elastic scattering of Beryllium isotopes near the Coulomb barrier
Di Pietro, A.; Figuera, P.; Amorini, F.; Fisichella, M.; Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Randisi, G.; Rizzo, F.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.; Torresi, D.; Papa, M.; Acosta, L.; Martel, I.; Perez-Bernal, F.; Borge, M. J. G.; Tengblad, O.
2011-10-28
In this contribution, results of experiments performed with the three Beryllium isotopes {sup 9,10,11}Be on a medium mass {sup 64}Zn target, at a center of mass energy of {approx_equal}1.4 the Coulomb barrier, will be discussed. Elastic scattering angular distributions have been measured for the {sup 9,10}Be reactions. In the {sup 11}Be case the quasielastic scattering angular distribution was obtained. In the halo nucleus case, the angular distribution exhibit a non-Fresnel-type pattern with a strong damping of the Coulomb-nuclear interference peak. Moreover, it is found that the total reaction cross-section for the halo nucleus induced collision is more than double the ones extracted in the collisions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the {sup 11}Be case could be attributed to transfer and/or break-up events.
Coulomb artifacts and bottomonium hyperfine splitting in lattice NRQCD
NASA Astrophysics Data System (ADS)
Liu, T.; Penin, A. A.; Rayyan, A.
2017-02-01
We study the role of the lattice artifacts associated with the Coulomb binding effects in the analysis of the heavy quarkonium within lattice NRQCD. We find that a "na¨ıve" perturbative matching generates spurious linear Coulomb artifacts, which result in a large systematic error in the lattice predictions for the heavy quarkonium spectrum. This effect is responsible, in particular, for the discrepancy between the recent determinations of the bottomonium hyperfine splitting in the radiatively improved lattice NRQCD [1, 2]. We show that the correct matching procedure which provides full control over discretization errors is based on the asymptotic expansion of the lattice theory about the continuum limit, which gives M Y(1 S) - M ηb (1 S) = 52.9 ± 5.5 MeV [1].
Structural phase transitions and topological defects in ion Coulomb crystals
Partner, Heather L.; Nigmatullin, Ramil; Burgermeister, Tobias; Keller, Jonas; Pyka, Karsten; Plenio, Martin B.; Retzker, Alex; Zurek, Wojciech Hubert; del Campo, Adolfo; Mehlstaubler, Tanja E.
2014-11-19
We use laser-cooled ion Coulomb crystals in the well-controlled environment of a harmonic radiofrequency ion trap to investigate phase transitions and defect formation. Topological defects in ion Coulomb crystals (kinks) have been recently proposed for studies of nonlinear physics with solitons and as carriers of quantum information. Defects form when a symmetry breaking phase transition is crossed non-adiabatically. For a second order phase transition, the Kibble-Zurek mechanism predicts that the formation of these defects follows a power law scaling in the rate of the transition. We demonstrate a scaling of defect density and describe kink dynamics and stability. We further discuss the implementation of mass defects and electric fields as first steps toward controlled kink preparation and manipulation.
Orbital ice: An exact Coulomb phase on the diamond lattice
Chern Giawei; Wu Congjun
2011-12-15
We demonstrate the existence of an orbital Coulomb phase as the exact ground state of a p-orbital exchange Hamiltonian on the diamond lattice. The Coulomb phase is an emergent state characterized by algebraic dipolar correlations and a gauge structure resulting from local constraints (ice rules) of the underlying lattice models. For most ice models on the pyrochlore lattice, these local constraints are a direct consequence of minimizing the energy of each individual tetrahedron. On the contrary, the orbital ice rules are emergent phenomena resulting from the quantum orbital dynamics. We show that the orbital ice model exhibits an emergent geometrical frustration by mapping the degenerate quantum orbital ground states to the spin-ice states obeying the 2-in-2-out constraints on the pyrochlore lattice. We also discuss possible realization of the orbital ice model in optical lattices with p-band fermionic cold atoms.
Coulomb path'' interference in low energy He sup + + He collisions
Swenson, J.K. ); Burgdoerfer, J. ); Meyer, F.W.; Havener, C.C.; Gregory, D.C.; Stolterfoht, N. )
1990-01-01
A new interference mechanism, analogous to classic'' double-slit electron scattering, has been identified in low energy ion-atom collisions. This Coulomb path'' interference results from the existence of two trajectories, indistinguishable with respect to laboratory energy and emission angle, along which ejected autoionizing electrons may be scattered by the attractive Coulomb potential of the slowly receding spectator ion. We present a simple semi-classical model for this effect in which we account for the path dependence of the amplitude of the ejected electron following decay of the autoionizing state. Calculated model lineshapes are found to be in excellent agreement with strong angular dependence of the interference structure observed in the He target 2s{sup 2} {sup 1}S autoionizing lineshape measured near 0{degree} following 10 keV He{sup +} + He collisions.
Coulomb chronometry to probe the decay mechanism of hot nuclei
NASA Astrophysics Data System (ADS)
Gruyer, D.; Frankland, J. D.; Bonnet, E.; Chbihi, A.; Ademard, G.; Boisjoli, M.; Borderie, B.; Bougault, R.; Galichet, E.; Gauthier, J.; Guinet, D.; Lautesse, P.; Le Neindre, N.; Legouée, E.; Lombardo, I.; Lopez, O.; Manduci, L.; Marini, P.; Mazurek, K.; Nadtochy, P. N.; Pârlog, M.; Rivet, M. F.; Roy, R.; Rosato, E.; Spadaccini, G.; Verde, G.; Vient, E.; Vigilante, M.; Wieleczko, J. P.; Indra Collaboration
2015-12-01
In 129Xe+natSn central collisions from 8 to 25 MeV/nucleon, the three-fragment exit channel occurs with a significant cross section. We show that these fragments arise from two successive binary splittings of a heavy composite system. The sequence of fragment production is determined. Strong Coulomb proximity effects are observed in the three-fragment final state. A comparison with Coulomb trajectory calculations shows that the time scale between the consecutive breakups decreases with increasing bombarding energy, becoming quasisimultaneous above excitation energy E*=4.0 ±0.5 MeV /nucleon . This transition from sequential to simultaneous breakup was interpreted as the signature of the onset of multifragmentation for the three-fragment exit channel in this system.
Electronic cooling via interlayer Coulomb coupling in multilayer epitaxial graphene
Mihnev, Momchil T.; Tolsma, John R.; Divin, Charles J.; Sun, Dong; Asgari, Reza; Polini, Marco; Berger, Claire; de Heer, Walt A.; MacDonald, Allan H.; Norris, Theodore B.
2015-01-01
In van der Waals bonded or rotationally disordered multilayer stacks of two-dimensional (2D) materials, the electronic states remain tightly confined within individual 2D layers. As a result, electron–phonon interactions occur primarily within layers and interlayer electrical conductivities are low. In addition, strong covalent in-plane intralayer bonding combined with weak van der Waals interlayer bonding results in weak phonon-mediated thermal coupling between the layers. We demonstrate here, however, that Coulomb interactions between electrons in different layers of multilayer epitaxial graphene provide an important mechanism for interlayer thermal transport, even though all electronic states are strongly confined within individual 2D layers. This effect is manifested in the relaxation dynamics of hot carriers in ultrafast time-resolved terahertz spectroscopy. We develop a theory of interlayer Coulomb coupling containing no free parameters that accounts for the experimentally observed trends in hot-carrier dynamics as temperature and the number of layers is varied. PMID:26399955
Glassy Dynamics in Geometrically Frustrated Coulomb Liquids without Disorder
NASA Astrophysics Data System (ADS)
Mahmoudian, Samiyeh; Rademaker, Louk; Ralko, Arnaud; Fratini, Simone; Dobrosavljević, Vladimir
2015-07-01
We show that introducing long-range Coulomb interactions immediately lifts the massive ground state degeneracy induced by geometric frustration for electrons on quarter-filled triangular lattices in the classical limit. Important consequences include the stabilization of a stripe-ordered crystalline (global) ground state, but also the emergence of very many low-lying metastable states with amorphous "stripe-glass" spatial structures. Melting of the stripe order thus leads to a frustrated Coulomb liquid at intermediate temperatures, showing remarkably slow (viscous) dynamics, with very long relaxation times growing in Arrhenius fashion upon cooling, as typical of strong glass formers. On shorter time scales, the system falls out of equilibrium and displays the aging phenomena characteristic of supercooled liquids above the glass transition. Our results show remarkable similarity with the recent observations of charge-glass behavior in ultraclean triangular organic materials of the θ -(BEDT -TTF )2 family.
Is the ground state of Yang-Mills theory Coulombic?
Heinzl, T.; Ilderton, A.; Langfeld, K.; Lavelle, M.; McMullan, D.; Lutz, W.
2008-08-01
We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-Abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.
Stability of Dirac Liquids with Strong Coulomb Interaction
NASA Astrophysics Data System (ADS)
Tupitsyn, Igor S.; Prokof'ev, Nikolay V.
2017-01-01
We develop and apply the diagrammatic Monte Carlo technique to address the problem of the stability of the Dirac liquid state (in a graphene-type system) against the strong long-range part of the Coulomb interaction. So far, all attempts to deal with this problem in the field-theoretical framework were limited either to perturbative or random phase approximation and functional renormalization group treatments, with diametrically opposite conclusions. Our calculations aim at the approximation-free solution with controlled accuracy by computing vertex corrections from higher-order skeleton diagrams and establishing the renormalization group flow of the effective Coulomb coupling constant. We unambiguously show that with increasing the system size L (up to ln (L )˜40 ), the coupling constant always flows towards zero; i.e., the two-dimensional Dirac liquid is an asymptotically free T =0 state with divergent Fermi velocity.
Renormalization group analysis of graphene with a supercritical Coulomb impurity
NASA Astrophysics Data System (ADS)
Nishida, Yusuke
2016-08-01
We develop a field-theoretic approach to massless Dirac fermions in a supercritical Coulomb potential. By introducing an Aharonov-Bohm solenoid at the potential center, the critical Coulomb charge can be made arbitrarily small for one partial-wave sector, where a perturbative renormalization group analysis becomes possible. We show that a scattering amplitude for reflection of particle at the potential center exhibits the renormalization group limit cycle, i.e., log-periodic revolutions as a function of the scattering energy, revealing the emergence of discrete scale invariance. This outcome is further incorporated in computing the induced charge and current densities, which turn out to have power-law tails with coefficients log-periodic with respect to the distance from the potential center. Our findings are consistent with the previous prediction obtained by directly solving the Dirac equation and can in principle be realized by graphene experiments with charged impurities.
Coulomb excitation of C{sub 60} molecules
Esbensen, H.; Berry, H.G.; Cheng, S.
1995-08-01
The ionization and dissociation of C{sub 60} molecules in the Coulomb field from fast, highly-charged xenon ions was measured recently at ATLAS. The Coulomb excitation was modeled as a coherent excitation of the giant plasmon resonance. Guided by photo-absorption measurements, single-plasmon excitations were identified with the production of single-charged C{sub 60}{sup +} molecular ions. The calculated cross sections do indeed reproduce the beam energy-dependence of the measured C{sub 60}{sup +} yield. The calculations show that single-plasmon excitations are responsible for about half of the total reaction cross section. The other half, i.e., multiplasmon excitations, leads to multiple ionization and dissociation of the molecule.
A Coulomb collision algorithm for weighted particle simulations
NASA Technical Reports Server (NTRS)
Miller, Ronald H.; Combi, Michael R.
1994-01-01
A binary Coulomb collision algorithm is developed for weighted particle simulations employing Monte Carlo techniques. Charged particles within a given spatial grid cell are pair-wise scattered, explicitly conserving momentum and implicitly conserving energy. A similar algorithm developed by Takizuka and Abe (1977) conserves momentum and energy provided the particles are unweighted (each particle representing equal fractions of the total particle density). If applied as is to simulations incorporating weighted particles, the plasma temperatures equilibrate to an incorrect temperature, as compared to theory. Using the appropriate pairing statistics, a Coulomb collision algorithm is developed for weighted particles. The algorithm conserves energy and momentum and produces the appropriate relaxation time scales as compared to theoretical predictions. Such an algorithm is necessary for future work studying self-consistent multi-species kinetic transport.
Coulomb branch Hilbert series and three dimensional Sicilian theories
NASA Astrophysics Data System (ADS)
Cremonesi, Stefano; Hanany, Amihay; Mekareeya, Noppadol; Zaffaroni, Alberto
2014-09-01
We evaluate the Coulomb branch Hilbert series of mirrors of three dimensional Sicilian theories, which arise from compactifying the 6 d (2 , 0) theory with symmetry G on a circle times a Riemann surface with punctures. We obtain our result by gluing together the Hilbert series for building blocks T ρ ( G), where ρ is a certain partition related to the dual group of G, which we evaluated in a previous paper. The result is expressed in terms of a class of symmetric functions, the Hall-Littlewood polynomials. As expected from mirror symmetry, our results agree at genus zero with the superconformal index prediction for the Higgs branch Hilbert series of the Sicilian theories and extend it to higher genus. In the A 1 case at genus zero, we also evaluate the Coulomb branch Hilbert series of the Sicilian theory itself, showing that it only depends on the number of external legs.
Low-energy Coulomb excitation of Sr,9896 beams
NASA Astrophysics Data System (ADS)
Clément, E.; Zielińska, M.; Péru, S.; Goutte, H.; Hilaire, S.; Görgen, A.; Korten, W.; Doherty, D. T.; Bastin, B.; Bauer, C.; Blazhev, A.; Bree, N.; Bruyneel, B.; Butler, P. A.; Butterworth, J.; Cederkäll, J.; Delahaye, P.; Dijon, A.; Ekström, A.; Fitzpatrick, C.; Fransen, C.; Georgiev, G.; Gernhäuser, R.; Hess, H.; Iwanicki, J.; Jenkins, D. G.; Larsen, A. C.; Ljungvall, J.; Lutter, R.; Marley, P.; Moschner, K.; Napiorkowski, P. J.; Pakarinen, J.; Petts, A.; Reiter, P.; Renstrøm, T.; Seidlitz, M.; Siebeck, B.; Siem, S.; Sotty, C.; Srebrny, J.; Stefanescu, I.; Tveten, G. M.; Van de Walle, J.; Vermeulen, M.; Voulot, D.; Warr, N.; Wenander, F.; Wiens, A.; De Witte, H.; Wrzosek-Lipska, K.
2016-11-01
The structure of neutron-rich Sr,9896 nuclei was investigated by low-energy safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN, with the MINIBALL spectrometer. A rich set of transitional and diagonal E 2 matrix elements, including those for non-yrast structures, has been extracted from the differential Coulomb-excitation cross sections. The results support the scenario of a shape transition at N =60 , giving rise to the coexistence of a highly deformed prolate and a spherical configuration in 98Sr, and are compared to predictions from several theoretical calculations. The experimental data suggest a significant contribution of the triaxal degree of freedom in the ground state of both isotopes. In addition, experimental information on low-lying states in 98Rb has been obtained.
Quantum solution for the one-dimensional Coulomb problem
Nunez-Yepez, H. N.; Salas-Brito, A. L.; Solis, Didier A.
2011-06-15
The one-dimensional hydrogen atom has been a much studied system with a wide range of applications. Since the pioneering work of Loudon [R. Loudon, Am. J. Phys. 27, 649 (1959).], a number of different features related to the nature of the eigenfunctions have been found. However, many of the claims made throughout the years in this regard are not correct--such as the existence of only odd eigenstates or of an infinite binding-energy ground state. We explicitly show that the one-dimensional hydrogen atom does not admit a ground state of infinite binding energy and that the one-dimensional Coulomb potential is not its own supersymmetric partner. Furthermore, we argue that at the root of many such false claims lies the omission of a superselection rule that effectively separates the right side from the left side of the singularity of the Coulomb potential.
NASA Astrophysics Data System (ADS)
Li, Wei; Zhao, Jingkai; Zhang, Lei; Xia, Yinfeng; Liu, Nan; Li, Sujing; Zhang, Shihan
2016-01-01
A novel chemical absorption-biological reduction (CABR) integrated process, employing ferrous ethylenediaminetetraacetate (Fe(II)EDTA) as a solvent, is deemed as a potential option for NOx removal from the flue gas. Previous work showed that the Fe(II)EDTA concentration was critical for the NOx removal in the CABR process. In this work, the pathway of FeEDTA (Fe(III)/Fe(II)-EDTA) transformation was investigated to assess its impact on the NOx removal in a biofilter. Experimental results revealed that the FeEDTA transformation involved iron precipitation and EDTA degradation. X-ray photoelectron spectroscopy analysis confirmed the iron was precipitated in the form of Fe(OH)3. The iron mass balance analysis showed 44.2% of the added iron was precipitated. The EDTA degradation facilitated the iron precipitation. Besides chemical oxidation, EDTA biodegradation occurred in the biofilter. The addition of extra EDTA helped recover the iron from the precipitation. The transformation of FeEDTA did not retard the NO removal. In addition, EDTA rather than the iron concentration determined the NO removal efficiency.
Li, Wei; Zhao, Jingkai; Zhang, Lei; Xia, Yinfeng; Liu, Nan; Li, Sujing; Zhang, Shihan
2016-01-08
A novel chemical absorption-biological reduction (CABR) integrated process, employing ferrous ethylenediaminetetraacetate (Fe(II)EDTA) as a solvent, is deemed as a potential option for NOx removal from the flue gas. Previous work showed that the Fe(II)EDTA concentration was critical for the NOx removal in the CABR process. In this work, the pathway of FeEDTA (Fe(III)/Fe(II)-EDTA) transformation was investigated to assess its impact on the NOx removal in a biofilter. Experimental results revealed that the FeEDTA transformation involved iron precipitation and EDTA degradation. X-ray photoelectron spectroscopy analysis confirmed the iron was precipitated in the form of Fe(OH)3. The iron mass balance analysis showed 44.2% of the added iron was precipitated. The EDTA degradation facilitated the iron precipitation. Besides chemical oxidation, EDTA biodegradation occurred in the biofilter. The addition of extra EDTA helped recover the iron from the precipitation. The transformation of FeEDTA did not retard the NO removal. In addition, EDTA rather than the iron concentration determined the NO removal efficiency.
Park, Melissa
2012-01-01
In occupational therapy practice, the rich interweaving of procedural and narrative reasoning results in healing transformations. However, a lack of research focus on transformational processes perpetuates a focus on observable and measurable behaviors. In line with the movement toward evidence-based implementation research, this article focuses on a case study drawn from an ethnography of therapist-child-family interactions in a sensory integration-based clinic to provide a thick description of the moments leading up to and following changes in bodily and social engagement for a child with autism. Using theoretical resources on acted narratives and aesthetics, this article provides a developing method and language to show how an occupational therapist and a child with autism throw breaches to jointly create embodied metaphors of what matters to the child in his or her everyday life. A microanalysis of therapist-child bodily and sensing interactions also reveals how narrative and procedural reasoning converge in moments of pleasure that ultimately lead to outcomes in participation outside the clinic and confound characterizations of autistic aloneness. Implications for research on sensory integration approaches in general and social interventions for children with autism are discussed.
Coulomb excitations for a short linear chain of metallic shells
Zhemchuzhna, Liubov; Gumbs, Godfrey; Iurov, Andrii; Huang, Danhong; Gao, Bo
2015-03-15
A self-consistent-field theory is given for the electronic collective modes of a chain containing a finite number, N, of Coulomb-coupled spherical two-dimensional electron gases arranged with their centers along a straight line, for simulating electromagnetic response of a narrow-ribbon of metallic shells. The separation between nearest-neighbor shells is arbitrary and because of the quantization of the electron energy levels due to their confinement to the spherical surface, all angular momenta L of the Coulomb excitations, as well as their projections M on the quantization axis, are coupled. However, for incoming light with a given polarization, only one angular momentum quantum number is usually required. Therefore, the electromagnetic response of the narrow-ribbon of metallic shells is expected to be controlled externally by selecting different polarizations for incident light. We show that, when N = 3, the next-nearest-neighbor Coulomb coupling is larger than its value if they are located at opposite ends of a right-angle triangle forming the triad. Additionally, the frequencies of the plasma excitations are found to depend on the orientation of the line joining them with respect to the axis of quantization since the magnetic field generated from the induced oscillating electric dipole moment on one sphere can couple to the induced magnetic dipole moment on another. Although the transverse inter-shell electromagnetic coupling can be modeled by an effective dynamic medium, the longitudinal inter-shell Coulomb coupling, on the other hand, can still significantly modify the electromagnetic property of this effective medium between shells.
Stability characterizations of fixtured rigid bodies with Coulomb friction
PANG,J.S.; TRINKLE,JEFFREY C.
2000-02-15
This paper formally introduces several stability characterizations of fixtured three-dimensional rigid bodies initially at rest and in unilateral contact with Coulomb friction. These characterizations, weak stability and strong stability, arise naturally from the dynamic model of the system, formulated as a complementarity problem. Using the tools of complementarity theory, these characterizations are studied in detail to understand their properties and to develop techniques to identify the stability classifications of general systems subjected to known external loads.
Coulomb-Gauge Gluon Propagator and the Gribov Formula
Burgio, G.; Quandt, M.; Reinhardt, H.
2009-01-23
We analyze the lattice SU(2) Yang-Mills theory in the Coulomb gauge. We show that the static gluon propagator is multiplicative renormalizable and takes the simple form D(|p-vector|){sup -1}={radical}(|p-vector|{sup 2}+M{sup 4}/|p-vector|{sup 2}), proposed by Gribov through heuristic arguments many years ago. We find M=0.88(1) GeV{approx_equal}2{radical}({sigma})
On the Nonlocality of the Coulomb Gauge External Field Problem
NASA Astrophysics Data System (ADS)
Hraskó, Péter
The apparent nonlocality of the Coulomb gauge external field problem in electrodynamics is illustrated with an example in which nonlocality is especially striking. Explanation of this apparent nonlocal behaviour based on a purely local picture is given. A gauge invariant decomposition of the Lorentz-force into two terms with clear physical meanings is pointed out. Based on this decomposition derivation of the Aharonov-Bohm effect in terms of field strengths alone is given.
On the nonlocality of the Coulomb gauge external field problem
NASA Astrophysics Data System (ADS)
Hraskó, Péter
2016-10-01
The apparent nonlocality of the Coulomb gauge external field problem in electrodynamics is illustrated with an example in which nonlocality is especially striking. Explanation of this apparent nonlocal behaviour based on a purely local picture is given. A gauge invariant decomposition of the Lorentz-force into two terms with clear physical meanings is pointed out. Based on this decomposition derivation of the Aharonov-Bohm effect in terms of field strengths alone is given.
Coulomb crystallization of sympathetically cooled highly charged ions
NASA Astrophysics Data System (ADS)
Crespo López-Urrutia, José R.
2015-05-01
Wave functions of inner-shell electrons significantly overlap with the nucleus, whereby enormously magnified relativistic, quantum electrodynamic (QED) and nuclear size effects emerge. In highly charged ions (HCI), the relative reduction of electronic correlations contributions improves the visibility of these effects. This well known facts have driven research efforts with HCI, yet the typically high temperatures at which these can be prepared in the laboratory constitutes a serious hindrance for application of laser spectroscopic methods. The solution for this, cooling HCI down to crystallization has remained an elusive target for more than two decades. By applying laser cooling to an ensemble of Be+ ions, we build Coulomb crystals that we use for stopping the motion of HCI and for cooling them. HCI, in this case Ar13+ ions are extracted from an electron beam ion trap with an energy spread of a few 100's of eV, due to the ion temperature within the trap. Carefully timed electric pulses in a potential-gradient decelerate and bunch the HCI. We achieve Coulomb crystallization of these HCI by re-trapping them in a cryogenic linear radiofrequency trap where they are sympathetically cooled through Coulomb interaction with the directly laser-cooled ensemble. Furthermore, we also demonstrate cooling of a single Ar13+ ion by a single Be+ ion, prerequisite for quantum logic spectroscopy with potentially 10-19 relative accuracy. The strongly suppressed thermal motion of the embedded HCI offers novel possibilities for investigation of questions related to the time variation of fundamental constants, parity non-conservation effects, Lorentz invariance and quantum electrodynamics. Achieving a seven orders-of-magnitude decrease in HCI temperature, from the starting point at MK values in the ion source down to the mK range within the Coulomb crystal eliminates the major obstacle for HCI investigation with high precision laser spectroscopy and quantum computation schemes.
Can Coulomb repulsion for charged particle beams be overcome?
NASA Astrophysics Data System (ADS)
Retsky, Michael W.
2004-01-01
Mutual repulsion of discrete charged particles or Coulomb repulsion is widely considered to be an ultimate hard limit in charged particle optics. It prevents the ability to finely focus high current beams into a small spots at large distances from the defining apertures. A classic example is the 1970s era "Star Wars" study of an electron beam directed energy weapon as an orbiting antiballistic missile device. After much analysis, it was considered physically impossible to focus a 1000-amp 1-GeV beam into a 1-cm diameter spot 1000-km from the beam generator. The main reason was that a 1-cm diameter beam would spread to 5-m diameter at 1000-km due to Coulomb repulsion. Since this could not be overcome, the idea was abandoned. But is this true? What if the rays were reversed? That is, start with a 5-m beam converging slightly with the same nonuniform angular and energy distribution as the electrons from the original problem were spreading at 1000-km distance. Could Coulomb repulsion be overcome? Looking at the terms in computational studies, some are reversible while others are not. Since the nonreversible terms should be small, it might be possible to construct an electron beam directed energy weapon.
Implosive Interatomic Coulombic decay in the simplest molecular anion
NASA Astrophysics Data System (ADS)
Greene, Chris H.; Perez-Rios, Jesus; Slipchenko, Lyudmila
2016-05-01
Interatomic Coulombic decay (ICD) has been extensively studied in different systems: from diatomic systems such as He2 up to more complex chemical systems with interest in biochemistry. Independently of the size and complexity of the system, the ICD process proposed involves the emission of an electron through exchange of a virtual photon. The present theoretical study investigates the ICD process in the helium hydride anion, which involves two final product states that can be produced through a Coulomb implosion following high energy ejection of a He 1s electron accompanied by excitation to He+(n = 2) . One of the subsequent decay channels is associated with the usual emission of a single electron, to produce a stable molecule: HeH+, which can compete with the usual dissociated final state of the system. The second channel involves the emission of two electrons, leading to the usual Coulomb explosion of the final product ions He+(1 s) + H + . In addition, the process of formation of the helium hydride anion is analyzed in terms of the existing technology of ionic molecular beams and buffer gas cooling techniques. This work is supported by the National Science Foundation under Grant PHY-1306905.
Quasi-exactly solvable relativistic soft-core Coulomb models
Agboola, Davids Zhang, Yao-Zhong
2012-09-15
By considering a unified treatment, we present quasi exact polynomial solutions to both the Klein-Gordon and Dirac equations with the family of soft-core Coulomb potentials V{sub q}(r)=-Z/(r{sup q}+{beta}{sup q}){sup 1/q}, Z>0, {beta}>0, q{>=}1. We consider cases q=1 and q=2 and show that both cases are reducible to the same basic ordinary differential equation. A systematic and closed form solution to the basic equation is obtained using the Bethe ansatz method. For each case, the expressions for the energies and the allowed parameters are obtained analytically and the wavefunctions are derived in terms of the roots of a set of Bethe ansatz equations. - Highlights: Black-Right-Pointing-Pointer The relativistic bound-state solutions of the soft-core Coulomb models. Black-Right-Pointing-Pointer Quasi-exact treatments of the Dirac and Klein-Gordon equations for the soft-core Coulomb models. Black-Right-Pointing-Pointer Solutions obtained in terms of the roots to the Bethe ansatz equations. Black-Right-Pointing-Pointer The hidden Lie algebraic structure discussed for the models. Black-Right-Pointing-Pointer Results useful in describing mesonic atoms and interaction of intense laser fields with atom.
Electron interactions in graphene through an effective Coulomb potential
NASA Astrophysics Data System (ADS)
Rodrigues, Joao N. B.; Adam, Shaffique
A recent numerical work [H.-K. Tang et al, PRL 115, 186602 (2015)] considering graphene's π-electrons interacting through an effective Coulomb potential that is finite at short-distances, stressed the importance of the sp2 -electrons in determining the semimetal to Mott insulator phase transition in graphene. Some years ago, I. F. Herbut [PRL 97, 146401 (2006)] studied such a transition by mapping graphene's π-electrons into a Gross-Neveu model. From a different perspective, D. T. Son [PRB 75, 235423 (2007)] put the emphasis on the long-range interactions by modelling graphene as Dirac fermions interacting through a bare Coulomb potential. Here we build on these works and explore the phase diagram of Dirac fermions interacting through an effective Coulomb-like potential screened at short-distances. The interaction potential used allows for analytic results that controllably switch between the two perspectives above. This work was supported by the Singapore National Research Foundation (NRF-NRFF2012-01 and CA2DM medium-sized centre program) and by the Singapore Ministry of Education and Yale-NUS College (R-607-265-01312).
Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule.
Cloët, Ian C; Bentz, Wolfgang; Thomas, Anthony W
2016-01-22
In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q|≳0.5 GeV. The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei.
Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule
NASA Astrophysics Data System (ADS)
Cloët, Ian C.; Bentz, Wolfgang; Thomas, Anthony W.
2016-01-01
In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q |≳0.5 GeV . The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei.
Regularized friction and continuation: Comparison with Coulomb's law
NASA Astrophysics Data System (ADS)
Vigué, Pierre; Vergez, Christophe; Karkar, Sami; Cochelin, Bruno
2017-02-01
Periodic solutions of systems with friction are difficult to investigate because of the non-smooth nature of friction laws. This paper examines periodic solutions and most notably stick-slip, on a simple one-degree-of-freedom system (mass, spring, damper, and belt), with Coulomb's friction law, and with a regularized friction law (i.e. the friction coefficient becomes a function of relative speed, with a stiffness parameter). With Coulomb's law, the stick-slip solution is constructed step by step, which gives a usable existence condition. With the regularized law, the Asymptotic Numerical Method and the Harmonic Balance Method provide bifurcation diagrams with respect to the belt speed or normal force, and for several values of the regularization parameter. Formulations from the Coulomb case give the means of a comparison between regularized solutions and a standard reference. With an appropriate definition, regularized stick-slip motion exists, its amplitude increases with respect to the belt speed and its pulsation decreases with respect to the normal force.
Coulomb-dominated low-energy deuteron stripping
Austern, N. )
1991-02-01
Analysis of a three-body model shows that Coulomb polarization of the deuteron has very little influence on the branching ratio {ital A}({ital d},{ital p})/{ital A}({ital d},{ital n}) for transfer reactions on target nucleus {ital A} at very low deuteron energies (the Oppenheimer-Phillips effect). We see that polarization effects in transfer reactions are not related to the long range of the Coulomb field, but are caused by the more intense fields near the target nucleus. However, even in that region the induced dipole moment is limited by the deuteron binding, and it is small for low {ital Z} targets. We see in addition that the transfer amplitudes tend to be {ital insensitive} to any polarization admixtures in the entrance channel. On the other hand, the branching ratio can be affected by the Coulomb barrier for the bound final-state wave function of the proton, especially for very weakly bound final states. Brief remarks about the relation of stripping theory to special properties of the {ital d}+{ital d} system are included.
Ionization in an intense field considering Coulomb correction
NASA Astrophysics Data System (ADS)
Li, Jian; Huo, Yi-Ning; Tang, Zeng-Hua; Ma, Feng-Cai
2017-01-01
We derive a simple ionization rate formula for the ground state of a hydrogen atom in the velocity gauge under the conditions: ω \\ll 1 a.u. (a.u. is short for atomic unit) and γ \\ll 1 (ω is the laser frequency and γ is the Keldysh parameter). Comparisons are made among the different versions of the Keldysh–Faisal–Reiss (KFR) theory. The numerical study shows that with considering the quasi-classical (WKB) Coulomb correction in the final state of the ionized electron, the photoionization rate is enhanced compared with without considering the Coulomb correction, and the Reiss theory with the WKB Coulomb correction gives the correct result in the tunneling regime. Our concise formula of the ionization rate may provide an insight into the ionization mechanism for the ground state of a hydrogen atom. Project supported by the National Natural Science Foundation of China (Grant Nos. 11274149 and 11304185) and the Program of Shenyang Key Laboratory of Optoelectronic Materials and Technology, China (Grant No. F12-254-1-00).
Instabilities of Coulomb phases and quark confinement in QCD
Asorey, Manuel; Santagata, Alessandro
2009-01-01
The Gribov picture to quark confinement is based on the Coulomb phase instability due to the very large values that the effective α{sub s} coupling constant can reach in the infrared regime. The Gribov instability is driven by a vacuum decay into light quarks beyond a critical value of the coupling constant α{sub s}3π(1-√(2/3))/4 (for SU(3) gauge group). From first principles it has been shown the existence of an instability of the Coulomb phase in pure gauge theories for α≥√(2), much beyond the Gribov critical value. In this paper we analyze the effect of dynamical quarks in the instability of the Coulomb phase. We find a critical value of the coupling α=√(3) where a quark-antiquark pair creation mechanism leads to vacuum instability. However, the new critical value turns out to be larger than the pure gauge critical value α=√(2), unlike it is expected in the standard Gribov scenario. The result is analytically derived from first principles and provides further consistency to the picture where quark confinement is mainly driven by gluonic fluctuation instabilities.
NASA Astrophysics Data System (ADS)
Turker, Mustafa; Koc-San, Dilek
2015-02-01
This paper presents an integrated approach for the automatic extraction of rectangular- and circular-shape buildings from high-resolution optical spaceborne images using the integration of support vector machine (SVM) classification, Hough transformation and perceptual grouping. The building patches are detected from the image using the binary SVM classification. The generated normalized digital surface model (nDSM) and the normalized difference vegetation index (NDVI) are incorporated in the classification process as additional bands. After detecting the building patches, the building boundaries are extracted through sequential processing of edge detection, Hough transformation and perceptual grouping. Those areas that are classified as building are masked and further processing operations are performed on the masked areas only. The edges of the buildings are detected through an edge detection algorithm that generates a binary edge image of the building patches. These edges are then converted into vector form through Hough transform and the buildings are constructed by means of perceptual grouping. To validate the developed method, experiments were conducted on pan-sharpened and panchromatic Ikonos imagery, covering the selected test areas in Batikent district of Ankara, Turkey. For the test areas that contain industrial buildings, the average building detection percentage (BDP) and quality percentage (QP) values were computed to be 93.45% and 79.51%, respectively. For the test areas that contain residential rectangular-shape buildings, the average BDP and QP values were computed to be 95.34% and 79.05%, respectively. For the test areas that contain residential circular-shape buildings, the average BDP and QP values were found to be 78.74% and 66.81%, respectively.
Sheibley, R.W.; Duff, J.H.; Jackman, A.P.; Triska, F.J.
2003-01-01
Inorganic N transformations were examined in streambed sediments from the Shingobee River using sediment perfusion cores. The experimental design simulated groundwater-stream water mixing within sediment cores, which provided a well-defined one-dimensional representation of in situ hydrologic conditions. Two distinct hydrologic and chemical settings were preserved in the sediment cores: the lowermost sediments, perfused with groundwater, remained anaerobic during the incubations, whereas the uppermost sediments, perfused with oxic water pumped from the overlying water column, simulated stream water penetration into the bed. The maintenance of oxic and anoxic zones formed a biologically active aerobic-anaerobic interface. Ammonium (NH4+) dissolved in groundwater was transported conservatively through the lower core zone but was removed as it mixed with aerated recycle water. Concurrently, a small quantity of nitrate (NO3-) equaling ???25% of the NH4+ loss was produced in the upper sediments. The NH4+ and NO3- profiles in the uppermost sediments resulted from coupled nitrification-denitrification, because assimilation and sorption were negligible. We hypothesize that anaerobic microsites within the aerated upper sediments supported denitrification. Rates of nitrification and denitrification in the perfusion cores ranged 42-209 and 53-160 mg N m-2 day-1, respectively. The use of modified perfusion cores permitted the identification and quantification of N transformations and verified process control by surface water exchange into the shallow hyporheic zone of the Shingobee River.
ERIC Educational Resources Information Center
Kalyn, Brenda
2006-01-01
Integrated learning is an exciting adventure for both teachers and students. It is not uncommon to observe the integration of academic subjects such as math, science, and language arts. However, educators need to recognize that movement experiences in physical education also can be linked to academic curricula and, may even lead the…
NASA Astrophysics Data System (ADS)
Mukhopadhyay, S.; Chatterjee, A.
2006-09-01
The integral integral F(r, r', vertical bar r - r'vertical bar) dr dr' where r and r' are N-dimensional position vectors can be transformed into a simple three-dimensional integral using Hylleraas coordinates. A simple derivation of this result is presented.
Jackson, M I; Hiley, M J; Yeadon, M R
2011-10-13
In the table contact phase of gymnastics vaulting both dynamic and static friction act. The purpose of this study was to develop a method of simulating Coulomb friction that incorporated both dynamic and static phases and to compare the results with those obtained using a pseudo-Coulomb implementation of friction when applied to the table contact phase of gymnastics vaulting. Kinematic data were obtained from an elite level gymnast performing handspring straight somersault vaults using a Vicon optoelectronic motion capture system. An angle-driven computer model of vaulting that simulated the interaction between a seven segment gymnast and a single segment vaulting table during the table contact phase of the vault was developed. Both dynamic and static friction were incorporated within the model by switching between two implementations of the tangential frictional force. Two vaulting trials were used to determine the model parameters using a genetic algorithm to match simulations to recorded performances. A third independent trial was used to evaluate the model and close agreement was found between the simulation and the recorded performance with an overall difference of 13.5%. The two-state simulation model was found to be capable of replicating performance at take-off and also of replicating key contact phase features such as the normal and tangential motion of the hands. The results of the two-state model were compared to those using a pseudo-Coulomb friction implementation within the simulation model. The two-state model achieved similar overall results to those of the pseudo-Coulomb model but obtained solutions more rapidly.
NASA Technical Reports Server (NTRS)
Ambrosia, Vincent G.; Myers, Jeffrey S.; Ekstrand, Robert E.; Fitzgerald, Michael T.
1991-01-01
A simple method for enhancing the spatial and spectral resolution of disparate data sets is presented. Two data sets, digitized aerial photography at a nominal spatial resolution 3,7 meters and TMS digital data at 24.6 meters, were coregistered through a bilinear interpolation to solve the problem of blocky pixel groups resulting from rectification expansion. The two data sets were then subjected to intensity-saturation-hue (ISH) transformations in order to 'blend' the high-spatial-resolution (3.7 m) digitized RC-10 photography with the high spectral (12-bands) and lower spatial (24.6 m) resolution TMS digital data. The resultant merged products make it possible to perform large-scale mapping, ease photointerpretation, and can be derived for any of the 12 available TMS spectral bands.
Steiger, Matthias G; Vitikainen, Marika; Uskonen, Pekka; Brunner, Kurt; Adam, Gerhard; Pakula, Tiina; Penttilä, Merja; Saloheimo, Markku; Mach, Robert L; Mach-Aigner, Astrid R
2011-01-01
Hypocrea jecorina is an industrially important filamentous fungus due to its effective production of hydrolytic enzymes. It has received increasing interest because of its ability to convert lignocellulosic biomass to monomeric sugars, which can be converted into biofuels or platform chemicals. Genetic engineering of strains is a highly important means of meeting the requirements of tailor-made applications. Therefore, we report the development of a transformation system that allows highly efficient gene targeting by using a tmus53 (human LIG4 homolog) deletion strain. Moreover, it permits the unlimited reuse of the same marker by employing a Cre/loxP-based excision system. Both marker insertion and marker excision can be positively selected for by combining resistance to hygromycin B and loss of sensitivity to fluoroacetamide. Finally, the marker pyr4, also positively selectable for insertion and loss, can be used to remove the cre gene.
Signatures of subband quantization in the Coulomb blockade regime of a disordered quantum wire
NASA Astrophysics Data System (ADS)
Liu, Wei; He, Jianhong; Guo, Huazhong; Gao, Jie
2017-01-01
We report experiments on the two-terminal conductance of a long disordered quantum wire in a perpendicular magnetic field. Pronouncedly enhanced magnetoconductance in magnetic fields of intermediate strength is observed in the Coulomb blockade regime, which is well explained using the boundary roughness scattering and the subband quantization of the quantum wire, by modeling the disordered quantum wire as that of a quantum dot defined in a quantum wire. Assuming a parabolic constriction in the disordered quantum wire, we further obtained the magnetic field dependence of high energy levels in the quantum dot and the gate voltage dependence of the effective width of the quantum wire. Our results may provide useful information for further studies on integrated structures in on-chip laboratories.
Equation satisfied by the energy-density functional for electron-electron mutual Coulomb repulsion
Joubert, Daniel P.
2011-10-15
It is shown that the electron-electron mutual Coulomb repulsion energy-density functional V{sub ee}{sup {gamma}}[{rho}] satisfies the equationV{sub ee}{sup {gamma}}[{rho}{sub N}{sup 1}]-V{sub ee}{sup {gamma}}[{rho}{sub N-1}{sup {gamma}}]={integral}d{sup 3}r({delta}V{sub ee}{sup {gamma}}[{rho}{sub N}{sup 1}]/{delta}{rho}{sub N}{sup 1}(r))[{rho}{sub N}{sup 1}(r)-{rho}{sub N-1}{sup {gamma}}(r)], where {rho}{sub N}{sup 1}(r) and {rho}{sub N-1}{sup {gamma}}(r) are N-electron and (N-1)-electron densities determined from the same adiabatic scaled external potential of the N-electron system at coupling strength {gamma}.
NASA Astrophysics Data System (ADS)
Moore, R.
2008-12-01
The pressure to take a more integrated approach both to science and to management increases by the day. At almost any scale from local to global, it is no longer possible to consider issues in isolation; to do so runs a high risk of creating more problems than are solved. The consequence of this situation is that there is strong encouragement in the scientific world not just to understand and to be able to predict the response of individual processes but also to predict how those processes will interact. The manager is similarly encouraged to think in the widest terms about the likely impact of any policy before it is implemented. A new reservoir may solve a water supply problem but will it adversely affect the fishing and hence the tourist trade? How will climate change impact biodiversity? Will the drugs for treating a flu pandemic adversely affect river water quality? One approach to predicting such impacts would be to create new models simulating more and more processes. This, however, is neither feasible nor useful and makes poor use of the huge investment in existing models. A better approach, with many additional benefits, would be to find a way of linking existing models and modelling components such as databases or visualisation systems. Against this background, the European Commission, as part of its research programme to facilitate the introduction of integrated water management, commissioned a community project to find a generic solution to the linking of simulation models at run time. The outcome of this work was the Open Modelling Interface (OpenMI) standard and the creation of the OpenMI Association, an open, non-proprietary, not-for-profit, international organisation for its support. The work has received widespread recognition and encouragement from across the world, especially in the USA. A second phase is now building a community to continue the OpenMI's development and promote its use. The community's vision, mission and implementation strategy
Coulomb Drag and Magnetotransport in Graphene Double Layers
NASA Astrophysics Data System (ADS)
Tutuc, Emanuel
2013-03-01
Graphene double layers, a set of two closely spaced graphene monolayers seperated by an ultra-thin dielectric, represent an interesting electron system to explore correlated electron states. We discuss the fabrication of such samples using a layer-by-layer transfer approach, the electron transport in individual layers at zero and in a high magnetic field, and Coulomb drag measurements. Coulomb drag, probed by flowing a drive current in one layer, and measuring the voltage drop in the opposite layer provides a direct measurement of the electron-electron scattering between the two layers, and can be used to probe the electron system ground state. Coulomb drag in graphene, measured as a function of both layer densities and temperature reveals two distinct regimes: (i) diffusive drag at elevated temperatures, above 50 K, and (ii) mesoscopic fluctuations-dominated drag at low temperatures. A second topic discussed here is a technique that allows a direct measurement of the Fermi energy in an electron system with an accuracy independent of the sample size, using a graphene double layer heterostructure. The underlying principle of the technique is that an interlayer bias applied to bring the top layer to the charge neutrality point is equal to the Fermi energy of the bottom layer, which in effect renders the top graphene layer a resistively detected Kelvin probe. We illustrate this method by measuring the Fermi velocity, Landau level spacing, and Landau level broadening in monolayer graphene. Work done in collaboration with S. Kim, I. Jo, J. Nah, D. Dillen, K. Lee, B. Fallahazad, Z. Yao, and S. K. Banerjee. We thank ONR, NRI, and NSF for support.
Coulomb excitation of levels in 143Nd and 145Nd
NASA Astrophysics Data System (ADS)
Drǎgulescu, E.; Ivaşcu, M.; Mihu, R.; Popescu, D.; Semenescu, G.; Paar, V.; Vretenar, D.
1984-04-01
The low-lying states of 143Nd and 154Nd have been studied by means of Coulomb excitation with 16O and α-particles. Angular distribution measurements were carried out for some transitions in 145Nd with 11.2 MeV α-particles. Level energy decay schemes and B(E2)↑ values were measured for two states in 143Nd and for six states in 145Nd. Some spin assignments have been established for the 145Nd nucleus. 143Nd and 145Nd have been theoretically described by coupling one and three particles, respectively, to quadrupole vibrations, and rather good agreement with experiment was achieved.
Heavy quarks, gluons and the confinement potential in Coulomb gauge
Popovici, Carina; Watson, Peter; Reinhardt, Hugo
2011-05-23
We consider the heavy quark limit of Coulomb gauge QCD, with the truncation of the Yang-Mills sector to include only (dressed) two-point functions. We find that the rainbow-ladder approximation to the gap and Bethe-Salpeter equations is nonperturbatively exact and moreover, we provide a direct connection between the temporal gluon propagator and the quark confinement potential. Further, we show that only bound states of color singlet quark-antiquark (meson) and quark-quark (SU(2) baryon) pairs are physically allowed.
Photodetachment of hydrogen negative ions with screened Coulomb interaction
Zhang, Song Bin; Chen, Xiang Jun; Wang, Jian Guo; Janev, R. K.; Qu, Yi Zhi
2010-06-15
The effects of Coulomb interaction screening on photodetachment cross sections of hydrogen negative ions below the n =2 excitation threshold is investigated by using the R-matrix method with pseudostates. The contributions of Feshbach and shape resonances to H{sup -} photodetachment cross section are presented when screening length (D) varies from D = {infinity} to D = 4.6 a.u. It is found that the interaction screening has dramatic effects on the photodetachment cross sections of hydrogen negative ions in the photoelectron energy region around the n = 2 excitation threshold by strongly affecting the evolution of near-threshold resonances.
A nonlinear Bloch model for Coulomb interaction in quantum dots
Bidegaray-Fesquet, Brigitte Keita, Kole
2014-02-15
In this paper, we first derive a Coulomb Hamiltonian for electron–electron interaction in quantum dots in the Heisenberg picture. Then we use this Hamiltonian to enhance a Bloch model, which happens to be nonlinear in the density matrix. The coupling with Maxwell equations in case of interaction with an electromagnetic field is also considered from the Cauchy problem point of view. The study is completed by numerical results and a discussion about the advisability of neglecting intra-band coherences, as is done in part of the literature.
Coulombic wall slip of concentrated soft-particle suspensions
NASA Astrophysics Data System (ADS)
Adams, Michael; Liu, Wei; Zhang, Zhibing; Fryer, Peter
2013-06-01
The coefficients of friction of concentrated soft-particle suspensions (tomato paste and a microgel suspension) were measured as a function of the slip velocity for a number of substrates. The data are interpreted using a micro-elastohydrodynamic model that is consistent with significant bulk frictional dissipation and an increase in the number of particle-wall contacts with increasing normal stress. The origin of the Coulombic slip, which has not been observed previously for pastes, is ascribed to the sensitivity of the lubricating film thickness.
Proton radiography, nuclear cross sections and multiple Coulomb scattering
Sjue, Sky K.
2015-11-04
The principles behind proton radiography including multiple Coulomb scattering are discussed for a purely imaginary square well nucleus in the eikonal approximation. It is found that a very crude model can reproduce the angular dependence of the cross sections measured at 24 GeV/c. The largest differences are ~3% for the 4.56 mrad data, and ~4% for the 6.68 mrad data. The prospect of understanding how to model deterministically high-energy proton radiography over a very large range of energies is promising, but it should be tested more thoroughly.
Momentum correlation in the three-body Coulomb continuum problem
NASA Astrophysics Data System (ADS)
Zhang, Suimeng
2000-09-01
Following the work of Berakdar (1996 Phys. Rev. A 53 2316), momentum correlation in the three-body Coulomb continuum problem is considered by the introduction of effective Sommerfeld parameters for both the symmetric and the asymmetric geometry. The triple differential cross sections for electron impact ionization of atomic helium at incident energies of 50 eV in the asymmetric geometry are calculated. Results of this approach are compared with the absolute measurements, the results of the BBK model without modification, the convergent close-coupling calculations and the results of our earlier model.
Nonlocal and nonlinear electrostatics of a dipolar Coulomb fluid.
Sahin, Buyukdagli; Ralf, Blossey
2014-07-16
We study a model Coulomb fluid consisting of dipolar solvent molecules of finite extent which generalizes the point-like dipolar Poisson-Boltzmann model (DPB) previously introduced by Coalson and Duncan (1996 J. Phys. Chem. 100 2612) and Abrashkin et al (2007 Phys. Rev. Lett. 99 077801). We formulate a nonlocal Poisson-Boltzmann equation (NLPB) and study both linear and nonlinear dielectric response in this model for the case of a single plane geometry. Our results shed light on the relevance of nonlocal versus nonlinear effects in continuum models of material electrostatics.
Triaxiality near the 110Ru ground state from Coulomb excitation
NASA Astrophysics Data System (ADS)
Doherty, D. T.; Allmond, J. M.; Janssens, R. V. F.; Korten, W.; Zhu, S.; Zielińska, M.; Radford, D. C.; Ayangeakaa, A. D.; Bucher, B.; Batchelder, J. C.; Beausang, C. W.; Campbell, C.; Carpenter, M. P.; Cline, D.; Crawford, H. L.; David, H. M.; Delaroche, J. P.; Dickerson, C.; Fallon, P.; Galindo-Uribarri, A.; Kondev, F. G.; Harker, J. L.; Hayes, A. B.; Hendricks, M.; Humby, P.; Girod, M.; Gross, C. J.; Klintefjord, M.; Kolos, K.; Lane, G. J.; Lauritsen, T.; Libert, J.; Macchiavelli, A. O.; Napiorkowski, P. J.; Padilla-Rodal, E.; Pardo, R. C.; Reviol, W.; Sarantites, D. G.; Savard, G.; Seweryniak, D.; Srebrny, J.; Varner, R.; Vondrasek, R.; Wiens, A.; Wilson, E.; Wood, J. L.; Wu, C. Y.
2017-03-01
A multi-step Coulomb excitation measurement with the GRETINA and CHICO2 detector arrays was carried out with a 430-MeV beam of the neutron-rich 110Ru (t1/2 = 12 s) isotope produced at the CARIBU facility. This represents the first successful measurement following the post-acceleration of an unstable isotope of a refractory element. The reduced transition probabilities obtained for levels near the ground state provide strong evidence for a triaxial shape; a conclusion confirmed by comparisons with the results of beyond-mean-field and triaxial rotor model calculations.
Mean Field Evolution of Fermions with Coulomb Interaction
NASA Astrophysics Data System (ADS)
Porta, Marcello; Rademacher, Simone; Saffirio, Chiara; Schlein, Benjamin
2017-03-01
We study the many body Schrödinger evolution of weakly coupled fermions interacting through a Coulomb potential. We are interested in a joint mean field and semiclassical scaling, that emerges naturally for initially confined particles. For initial data describing approximate Slater determinants, we prove convergence of the many-body evolution towards Hartree-Fock dynamics. Our result holds under a condition on the solution of the Hartree-Fock equation, that we can only show in a very special situation (translation invariant data, whose Hartree-Fock evolution is trivial), but that we expect to hold more generally.
Quantum confinement and Coulomb blockade in isolated nanodiamond crystallites
NASA Astrophysics Data System (ADS)
Bolker, Asaf; Saguy, Cecile; Tordjman, Moshe; Kalish, Rafi
2013-07-01
We present direct experimental evidence of quantum confinement effects in single isolated nanodiamonds by scanning tunneling spectroscopy. For grains smaller than 4.5 nm, the band gap was found to increase with decreasing nanodiamond size and a well-defined, evenly spaced, 12-peak structure was observed on the conduction band side of the conductance curves. We attribute these peaks to the Coulomb blockade effect, reflecting the 12-fold degeneracy of the first electron-energy level in the confined nanodiamond. The present results shed light on the size dependence of the electronic properties of single nanodiamonds and are of major importance for future nanodiamond-based applications.
"Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications
NASA Technical Reports Server (NTRS)
Marshall, J. R.
1999-01-01
The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this
A solvable model for localized adsorption in a Coulomb system
Rosinberg, M.L.; Blum, L.; Lebowitz, J.L.
1986-07-01
A model for an interface with localized adsorption is presented, in which the surface has a distribution of sticky adhesive sites in contact with a Coulomb fluid. Contrary to the current literature on the electrical double layer the surface charge is in dynamic equilibrium with the bulk fluid. The sum rules obeyed by the one- and two-body correlation functions are investigated. Explicit results are obtained for a solvable model, the two-dimensional one-component plasma at reduced temperature 2. The effect of the granularity of the adsorbed charge on the adsorption isotherm is discussed.
Dynamic screening of the three-body coulomb interactions
NASA Astrophysics Data System (ADS)
Zhang-jin, Chen
1998-03-01
The BBK approach is modified by the introduction of effective Sommerfeld parameters for both symmetric and asymmetric geometries, according to the fact that the strength of any particular two-body Coulomb interaction is affected by the presence of the third particle. The triple differential cross sections for electron impact ionization of atomic helium at incident energies of 40 and 50 eV in asymmetric geometry are calculated. Results of this approach are found to be in good agreement with the absolute measurements and the only existing theoretical results of the convergent close-coupling method.
NASA Astrophysics Data System (ADS)
Ojeda-Guillén, D.; Mota, R. D.; Granados, V. D.
2014-08-01
We decouple the Dirac's radial equations in D+1 dimensions with Coulomb-type scalar and vector potentials through appropriate transformations. We study each of these uncoupled second-order equations in an algebraic way by using an su(1,1) algebra realization. Based on the theory of irreducible representations, we find the energy spectrum and the radial eigenfunctions. We construct the Perelomov coherent states for the Sturmian basis, which is the basis for the unitary irreducible representation of the su(1,1) Lie algebra. The physical radial coherent states for our problem are obtained by applying the inverse original transformations to the Sturmian coherent states.
NASA Astrophysics Data System (ADS)
Brogi, Bharat Bhushan; Chand, Shyam; Ahluwalia, P. K.
2015-06-01
Theoretical study of the Coulomb blockade effect on transport properties (Transmission Probability and I-V characteristics) for varied configuration of coupled quantum dot system has been studied by using Non Equilibrium Green Function(NEGF) formalism and Equation of Motion(EOM) method in the presence of magnetic flux. The self consistent approach and intra-dot Coulomb interaction is being taken into account. As the key parameters of the coupled quantum dot system such as dot-lead coupling, inter-dot tunneling and magnetic flux threading through the system can be tuned, the effect of asymmetry parameter and magnetic flux on this tuning is being explored in Coulomb blockade regime. The presence of the Coulomb blockade due to on-dot Coulomb interaction decreases the width of transmission peak at energy level ɛ + U and by adjusting the magnetic flux the swapping effect in the Fano peaks in asymmetric and symmetric parallel configuration sustains despite strong Coulomb blockade effect.
NASA Astrophysics Data System (ADS)
Kadic, Muamer; Guenneau, Sébastien; Enoch, Stefan; Huidobro, Paloma A.; Martín-Moreno, Luis; García-Vidal, Francisco J.; Renger, Jan; Quidant, Romain
2012-07-01
Surface plasmons polaritons (SPPs) at metal/dielectric interfaces have raised lots of expectations in the on-going quest towards scaling down optical devices. SPP optics offers a powerful and flexible platform for real two-dimensional integrated optics, capable of supporting both light and electrons. Yet, a full exploitation of the features of SPPs is conditioned by an accurate control of their flow. Most efforts have so far focused on the extrapolation of concepts borrowed from guided optics. This strategy has already led to many important breakthroughs but a fully deterministic control of SPP modes remains a challenge. Recently, the field of optics was stimulated by a novel paradigm, transformation optics, which offers the capability to control light flow in any desired fashion. While it has already significantly contributed to the design of metamaterials with unprecedented optical properties, its versatility offers new opportunities towards a fully deterministic control of SPPs and the design of a new class of plasmonic functionalities. Here, we review recent progress in the application of transformation optics to SPPs. We first briefly describe the theoretical formalism of transformation plasmonics, focusing on its specificities over its three-dimensional optical counterpart. Numerical simulations are then used to illustrate its capability to tame SPP flows at a metal interface patterned with a dielectric load. Finally, we review recent experimental implementations leading to unique SPP functionalities at optical frequencies.
Wen, Xiao-Yong; Yan, Zhenya
2015-12-01
We study higher-order rogue wave (RW) solutions of the coupled integrable dispersive AB system (also called Pedlosky system), which describes the evolution of wave-packets in a marginally stable or unstable baroclinic shear flow in geophysical fluids. We propose its continuous-wave (CW) solutions and existent conditions for their modulation instability to form the rogue waves. A new generalized N-fold Darboux transformation (DT) is proposed in terms of the Taylor series expansion for the spectral parameter in the Darboux matrix and its limit procedure and applied to the CW solutions to generate multi-rogue wave solutions of the coupled AB system, which satisfy the general compatibility condition. The dynamical behaviors of these higher-order rogue wave solutions demonstrate both strong and weak interactions by modulating parameters, in which some weak interactions can generate the abundant triangle, pentagon structures, etc. Particularly, the trajectories of motion of peaks and depressions of profiles of the first-order RWs are explicitly analyzed. The generalized DT method used in this paper can be extended to other nonlinear integrable systems. These results may be useful for understanding the corresponding rogue-wave phenomena in fluid mechanics and related fields.
Coulomb-corrected molecular orbital tomography of nitrogen
NASA Astrophysics Data System (ADS)
Zhai, Chunyang; He, Lixin; Lan, Pengfei; Zhu, Xiaosong; Li, Yang; Wang, Feng; Shi, Wenjing; Zhang, Qingbin; Lu, Peixiang
2016-03-01
High-order harmonic generation (HHG) from aligned molecules has provided a promising way to probe the molecular orbital with an Ångström resolution. This method, usually called molecular orbital tomography (MOT) replies on a simple assumption of the plane-wave approximation (PW), which has long been questioned due to that PW approximation is known to be valid in the keV energy region. However, the photon energy is usually no more than 100 eV in HHG. In this work, we experimentally reconstruct the highest occupied molecular orbital (HOMO) of nitrogen (N2) by using a Coulomb-corrected MOT (CCMOT) method. In our scheme, the molecular continuum states are described by a Coulomb wave function instead of the PW approximation. With CCMOT, the reconstructed orbital is demonstrated to agree well with the theoretical prediction and retain the main features of the HOMO of N2. Compared to the PW approximation method, the CCMOT shows a significant improvement in eliminating the artificial structures caused by PW approximation.
Exact linearized Coulomb collision operator in the moment expansion
Ji, Jeong-Young; Held, Eric D.
2006-10-15
In the moment expansion, the Rosenbluth potentials, the linearized Coulomb collision operators, and the moments of the collision operators are analytically calculated for any moment. The explicit calculation of Rosenbluth potentials converts the integro-differential form of the Coulomb collision operator into a differential operator, which enables one to express the collision operator in a simple closed form for any arbitrary mass and temperature ratios. In addition, it is shown that gyrophase averaging the collision operator acting on arbitrary distribution functions is the same as the collision operator acting on the corresponding gyrophase averaged distribution functions. The moments of the collision operator are linear combinations of the fluid moments with collision coefficients parametrized by mass and temperature ratios. Useful forms involving the small mass-ratio approximation are easily found since the collision operators and their moments are expressed in terms of the mass ratio. As an application, the general moment equations are explicitly written and the higher order heat flux equation is derived.
Coulomb interaction effects on the Majorana states in quantum wires.
Manolescu, A; Marinescu, D C; Stanescu, T D
2014-04-30
The stability of the Majorana modes in the presence of a repulsive interaction is studied in the standard semiconductor wire-metallic superconductor configuration. The effects of short-range Coulomb interaction, which is incorporated using a purely repulsive δ-function to model the strong screening effect due to the presence of the superconductor, are determined within a Hartree-Fock approximation of the effective Bogoliubov-De Gennes Hamiltonian that describes the low-energy physics of the wire. Through a numerical diagonalization procedure we obtain interaction corrections to the single particle eigenstates and calculate the extended topological phase diagram in terms of the chemical potential and the Zeeman energy. We find that, for a fixed Zeeman energy, the interaction shifts the phase boundaries to a higher chemical potential, whereas for a fixed chemical potential this shift can occur either at lower or higher Zeeman energies. These effects can be interpreted as a renormalization of the g-factor due to the interaction. The minimum Zeeman energy needed to realize Majorana fermions decreases with the increasing strength of the Coulomb repulsion. Furthermore, we find that in wires with multi-band occupancy this effect can be enhanced by increasing the chemical potential, i.e. by occupying higher energy bands.
Super-Coulombic atom-atom interactions in hyperbolic media.
Cortes, Cristian L; Jacob, Zubin
2017-01-25
Dipole-dipole interactions, which govern phenomena such as cooperative Lamb shifts, superradiant decay rates, Van der Waals forces and resonance energy transfer rates, are conventionally limited to the Coulombic near-field. Here we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole-dipole coupling, referred to as a super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom-atom interactions in hyperbolic media confirming the giant long-range enhancement. We also propose multiple experimental platforms to verify our predicted effect with phonon-polaritonic hexagonal boron nitride, plasmonic super-lattices and hyperbolic meta-surfaces as well. Our work paves the way for the control of cold atoms above hyperbolic meta-surfaces and the study of many-body physics with hyperbolic media.
Interatomic Coulombic decay cascades in multiply excited neon clusters
Nagaya, K.; Iablonskyi, D.; Golubev, N. V.; Matsunami, K.; Fukuzawa, H.; Motomura, K.; Nishiyama, T.; Sakai, T.; Tachibana, T.; Mondal, S.; Wada, S.; Prince, K. C.; Callegari, C.; Miron, C.; Saito, N.; Yabashi, M.; Demekhin, Ph. V.; Cederbaum, L. S.; Kuleff, A. I.; Yao, M.; Ueda, K.
2016-01-01
In high-intensity laser light, matter can be ionized by direct multiphoton absorption even at photon energies below the ionization threshold. However on tuning the laser to the lowest resonant transition, the system becomes multiply excited, and more efficient, indirect ionization pathways become operative. These mechanisms are known as interatomic Coulombic decay (ICD), where one of the species de-excites to its ground state, transferring its energy to ionize another excited species. Here we show that on tuning to a higher resonant transition, a previously unknown type of interatomic Coulombic decay, intra-Rydberg ICD occurs. In it, de-excitation of an atom to a close-lying Rydberg state leads to electron emission from another neighbouring Rydberg atom. Moreover, systems multiply excited to higher Rydberg states will decay by a cascade of such processes, producing even more ions. The intra-Rydberg ICD and cascades are expected to be ubiquitous in weakly-bound systems exposed to high-intensity resonant radiation. PMID:27917867
Interatomic Coulombic decay cascades in multiply excited neon clusters
NASA Astrophysics Data System (ADS)
Nagaya, K.; Iablonskyi, D.; Golubev, N. V.; Matsunami, K.; Fukuzawa, H.; Motomura, K.; Nishiyama, T.; Sakai, T.; Tachibana, T.; Mondal, S.; Wada, S.; Prince, K. C.; Callegari, C.; Miron, C.; Saito, N.; Yabashi, M.; Demekhin, Ph. V.; Cederbaum, L. S.; Kuleff, A. I.; Yao, M.; Ueda, K.
2016-12-01
In high-intensity laser light, matter can be ionized by direct multiphoton absorption even at photon energies below the ionization threshold. However on tuning the laser to the lowest resonant transition, the system becomes multiply excited, and more efficient, indirect ionization pathways become operative. These mechanisms are known as interatomic Coulombic decay (ICD), where one of the species de-excites to its ground state, transferring its energy to ionize another excited species. Here we show that on tuning to a higher resonant transition, a previously unknown type of interatomic Coulombic decay, intra-Rydberg ICD occurs. In it, de-excitation of an atom to a close-lying Rydberg state leads to electron emission from another neighbouring Rydberg atom. Moreover, systems multiply excited to higher Rydberg states will decay by a cascade of such processes, producing even more ions. The intra-Rydberg ICD and cascades are expected to be ubiquitous in weakly-bound systems exposed to high-intensity resonant radiation.
Laser-Driven Recollisions under the Coulomb Barrier
NASA Astrophysics Data System (ADS)
Keil, Th.; Popruzhenko, S. V.; Bauer, D.
2016-12-01
Photoelectron spectra obtained from the ab initio solution of the time-dependent Schrödinger equation can be in striking disagreement with predictions by the strong-field approximation (SFA), not only at low energy but also around twice the ponderomotive energy where the transition from the direct to the rescattered electrons is expected. In fact, the relative enhancement of the ionization probability compared to the SFA in this regime can be several orders of magnitude. We show for which laser and target parameters such an enhancement occurs and for which the SFA prediction is qualitatively good. The enhancement is analyzed in terms of the Coulomb-corrected action along analytic quantum orbits in the complex-time plane, taking soft recollisions under the Coulomb barrier into account. These recollisions in complex time and space prevent a separation into sub-barrier motion up to the "tunnel exit" and subsequent classical dynamics. Instead, the entire quantum path up to the detector determines the ionization probability.
Enhancement of the Coulomb collision rate by individual particle wakes
NASA Astrophysics Data System (ADS)
Baalrud, Scott; Scheiner, Brett
2013-09-01
Charged particles moving in a plasma leave a trailing wake in their electric potential profile associated with the response function of the medium. For superthermal particles, these wakes can cause significant departures from the oft-assumed screened Coulomb potential profile. The wakes extend the interaction length scale beyond the Debye screening length for collisions between fast test particles and field particles in their wake. This can increase the Coulomb collision rate for velocities beyond the thermal speed. To demonstrate this effect, we consider the relaxation rate due to electron-electron collisions of an electron distribution function with initially depleted tails, as is common near boundary sheaths or double layers. This problem is related to Langmuir's paradox. We compare the standard Landau (Fokker-Planck) collision operator, which does not account for wakes, with the Lenard-Balescu collision operator, which includes wake effects through the linear dielectric response function. For this distribution, the linear dielectric is described by the incomplete plasma dispersion function. We compare the collision operators directly as well as the relaxation rate determined from a hybrid kinetic-fluid model. S. D. Baalrud, Phys. Plasmas 20, 012118 (2013).
Revision of the Coulomb logarithm in the ideal plasma
Mulser, P. Alber, G.; Murakami, M.
2014-04-15
The standard picture of the Coulomb logarithm in the ideal plasma is controversial, the arguments for the lower cut off need revision. The two cases of far subthermal and of far superthermal electron drift motions are accessible to a rigorous analytical treatment. We show that the lower cut off b{sub min} is a function of symmetry and shape of the shielding cloud, it is not universal. In the subthermal case, shielding is spherical and b{sub min} is to be identified with the de Broglie wavelength; at superthermal drift the shielding cloud exhibits cylindrical (axial) symmetry and b{sub min} is the classical parameter of perpendicular deflection. In both situations, the cut offs are determined by the electron-ion encounters at large collision parameters. This is in net contrast to the governing standard interpretation that attributes b{sub min} to the Coulomb singularity at vanishing collision parameters b and, consequently, assigns it universal validity. The origin of the contradictions in the traditional picture is analyzed.
Super-Coulombic atom–atom interactions in hyperbolic media
Cortes, Cristian L.; Jacob, Zubin
2017-01-01
Dipole–dipole interactions, which govern phenomena such as cooperative Lamb shifts, superradiant decay rates, Van der Waals forces and resonance energy transfer rates, are conventionally limited to the Coulombic near-field. Here we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole–dipole coupling, referred to as a super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom–atom interactions in hyperbolic media confirming the giant long-range enhancement. We also propose multiple experimental platforms to verify our predicted effect with phonon–polaritonic hexagonal boron nitride, plasmonic super-lattices and hyperbolic meta-surfaces as well. Our work paves the way for the control of cold atoms above hyperbolic meta-surfaces and the study of many-body physics with hyperbolic media. PMID:28120826
Super-Coulombic atom-atom interactions in hyperbolic media
NASA Astrophysics Data System (ADS)
Cortes, Cristian L.; Jacob, Zubin
2017-01-01
Dipole-dipole interactions, which govern phenomena such as cooperative Lamb shifts, superradiant decay rates, Van der Waals forces and resonance energy transfer rates, are conventionally limited to the Coulombic near-field. Here we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole-dipole coupling, referred to as a super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom-atom interactions in hyperbolic media confirming the giant long-range enhancement. We also propose multiple experimental platforms to verify our predicted effect with phonon-polaritonic hexagonal boron nitride, plasmonic super-lattices and hyperbolic meta-surfaces as well. Our work paves the way for the control of cold atoms above hyperbolic meta-surfaces and the study of many-body physics with hyperbolic media.
Pore fluid pressure, apparent friction, and Coulomb failure
Beeler, N.M.; Simpson, R.W.; Hickman, S.H.; Lockner, D.A.
2000-01-01
Many recent studies of stress-triggered seismicity rely on a fault failure model with a single free parameter, the apparent coefficient of friction, presumed to be a material constant with possible values 0 ≤ μ′ ≤ 1. These studies may present a misleading view of fault strength and the role of pore fluid pressure in earthquake failure. The parameter μ′ is intended to incorporate the effects of both friction and pore pressure, but is a material constant only if changes in pore fluid pressure induced by changes in stress are proportional to the normal stress change across the potential failure plane. Although specific models of fault zones permit such a relation, neither is it known that fault zones within the Earth behave this way, nor is this behavior expected in all cases. In contrast, for an isotropic homogeneous poroelastic model the pore pressure changes are proportional to changes in mean stress, μ′ is not a material constant, and −∞ ≤ μ′ ≤ +∞. Analysis of the change in Coulomb failure stress for tectonically loaded reverse and strike-slip faults shows considerable differences between these two pore pressure models, suggesting that such models might be distinguished from one another using observations of triggered seismicity (e.g., aftershocks). We conclude that using the constant apparent friction model exclusively in studies of Coulomb failure stress is unwise and could lead to significant errors in estimated stress change and seismic hazard.
Coulomb-corrected molecular orbital tomography of nitrogen.
Zhai, Chunyang; He, Lixin; Lan, Pengfei; Zhu, Xiaosong; Li, Yang; Wang, Feng; Shi, Wenjing; Zhang, Qingbin; Lu, Peixiang
2016-03-22
High-order harmonic generation (HHG) from aligned molecules has provided a promising way to probe the molecular orbital with an Ångström resolution. This method, usually called molecular orbital tomography (MOT) replies on a simple assumption of the plane-wave approximation (PW), which has long been questioned due to that PW approximation is known to be valid in the keV energy region. However, the photon energy is usually no more than 100 eV in HHG. In this work, we experimentally reconstruct the highest occupied molecular orbital (HOMO) of nitrogen (N2) by using a Coulomb-corrected MOT (CCMOT) method. In our scheme, the molecular continuum states are described by a Coulomb wave function instead of the PW approximation. With CCMOT, the reconstructed orbital is demonstrated to agree well with the theoretical prediction and retain the main features of the HOMO of N2. Compared to the PW approximation method, the CCMOT shows a significant improvement in eliminating the artificial structures caused by PW approximation.
Exact linearized Coulomb collision operator in the moment expansion
Ji, Jeong -Young; Held, Eric D.
2006-10-05
In the moment expansion, the Rosenbluth potentials, the linearized Coulomb collision operators, and the moments of the collision operators are analytically calculated for any moment. The explicit calculation of Rosenbluth potentials converts the integro-differential form of the Coulomb collision operator into a differential operator, which enables one to express the collision operator in a simple closed form for any arbitrary mass and temperature ratios. In addition, it is shown that gyrophase averaging the collision operator acting on arbitrary distribution functions is the same as the collision operator acting on the corresponding gyrophase averaged distribution functions. The moments of the collisionmore » operator are linear combinations of the fluid moments with collision coefficients parametrized by mass and temperature ratios. Furthermore, useful forms involving the small mass-ratio approximation are easily found since the collision operators and their moments are expressed in terms of the mass ratio. As an application, the general moment equations are explicitly written and the higher order heat flux equation is derived.« less
Influence of the Coulomb Force on Spray Cooling
NASA Astrophysics Data System (ADS)
Kuhlman, John M.; Kreitzer, Paul J.; Mehra, Deepak; Gray, Donald D.; Yerkes, Kirk L.
2007-01-01
Effects of the Coulomb electrical body force on heat transfer performance of an instrumented spray cooling experiment are reported. Heat transfer performance is documented for a range of spray volume flow rates and heater power levels using the dielectric liquids, FC-72 and HFE-7000, sprayed onto a Thick Film Resistor (TFR) heater; along with flow visualization results using a transparent Indium-Tin Oxide (ITO) heater. Two Coulomb force electrode geometries show modest but consistent improvements in heat transfer (order of 5-15%), but only at heat fluxes where boiling of the liquid film occurs. Flow visualization shows a highly contorted liquid film forming on the heater surface. These flow visualization results are used to aid in the estimation of characteristic time scales governing the effects of surface tension, gravity, heating of the liquid film, and vaporization of the film. For the present dense liquid sprays, it is concluded that none of these time scales are as short as the average time between droplet impacts into a heater surface area equal to the estimated size of the thin, crater-like liquid films formed by a previous droplet impact.
Pederson, Mark R
2015-04-14
It is tacitly accepted that, for practical basis sets consisting of N functions, solution of the two-electron Coulomb problem in quantum mechanics requires storage of O(N(4)) integrals in the small N limit. For localized functions, in the large N limit, or for planewaves, due to closure, the storage can be reduced to O(N(2)) integrals. Here, it is shown that the storage can be further reduced to O(N(2/3)) for separable basis functions. A practical algorithm, that uses standard one-dimensional Gaussian-quadrature sums, is demonstrated. The resulting algorithm allows for the simultaneous storage, or fast reconstruction, of any two-electron Coulomb integral required for a many-electron calculation on processors with limited memory and disk space. For example, for calculations involving a basis of 9171 planewaves, the memory required to effectively store all Coulomb integrals decreases from 2.8 Gbytes to less than 2.4 Mbytes.
A New Feature of the Screened Coulomb Potential in Momentum Space
NASA Astrophysics Data System (ADS)
Watanabe, Takashi; Hiratsuka, Yasuhisa; Oryu, Shinsho; Togawa, Yoshio
2017-03-01
A Coulomb equivalent screened Coulomb potential is proposed for solving the Schrödinger equation and/or the Calogero first order differential equation, where some critical range bands are obtained. Phase shifts for "any" two-charged particle system (from electron-electron to heavy ion-heavy ion) are reproduced by using the universal critical range bands and the appropriate Sommerfeld parameter over a very wide energy region. A Coulomb-like off-shell amplitude is introduced using two-potential theory without employing the usual Coulomb renormalization method.
"Coulombic Viscosity" In Granular Materials: Planetary and Astrophysical Implications
NASA Technical Reports Server (NTRS)
Marshall, J. R.
1999-01-01
The term "Coulombic viscosity" is introduced here to define an empirically observed phenomenon from experiments conducted in both microgravity, and in ground-based 1-g conditions. In the latter case, a sand attrition device was employed to test the longevity of aeolian materials by creating two intersecting grain-circulation paths or cells that would lead to most of the grain energy being expended on grain-to-grain collisions (simulating dune systems). In the areas in the device where gravitationally-driven grain-slurries recycled the sand, the slurries moved with a boundary-layer impeded motion down the chamber walls. Excessive electrostatic charging of the grains during these experiments was prevented by the use of an a.c. corona (created by a Tesla coil) through which the grains passed on every cycle. This created both positive and negative ions which neutralized the triboelectrically-generated grain charges. When the corona was switched on, the velocity of the wall-attached slurries increased by a factor of two as approximately determined by direct observation. What appeared to be a freely-flowing slurry of grains impeded only by intergranular mechanical friction, had obviously been significantly retarded in its motion by electrostatic forces between the grains; with the charging reduced, the grains were able to move past one another without a flow "viscosity" imposed by the Coulombic intergranular forces. A similar phenomenon was observed during microgravity experiments aboard Space Shuttle in USML-1 & USML-2 spacelabs where freely-suspended clouds of sand were being investigated for their potential to for-m aggregates. In this environment, the grains were also charged electrostatically (by natural processes prior to flight), but were free from the intervention of gravity in their interactions. The grains were dispersed into dense clouds by bursts of air turbulence and allowed to form aggregates as the ballistic and turbulent motions damped out. During this
Perkyns, John S.; Lynch, Gillian C.; Howard, Jesse J.; Pettitt, Bernard M.
2010-02-14
Solvation forces dominate protein structure and dynamics. Integral equation theories allow a rapid and accurate evaluation of the effect of solvent around a complex solute, without the sampling issues associated with simulations of explicit solvent molecules. Advances in integral equation theories make it possible to calculate the angle dependent average solvent structure around an irregular molecular solution. We consider two methodological problems here: the treatment of long-ranged forces without the use of artificial periodicity or truncations and the effect of closures. We derive a method for calculating the long-ranged Coulomb interaction contributions to three-dimensional distribution functions involving only a rewriting of the system of integral equations and introducing no new formal approximations. We show the comparison of the exact forms with those implied by the supercell method. The supercell method is shown to be a good approximation for neutral solutes whereas the new method does not exhibit the known problems of the supercell method for charged solutes. Our method appears more numerically stable with respect to thermodynamic starting state. We also compare closures including the Kovalenko–Hirata closure, the hypernetted-chain _HNC_ and an approximate three-dimensional bridge fu nction combined with the HNC closure. Comparisons to molecular dynamics results are made for water as well as for the protein solute bovine pancreatic trypsin inhibitor. The proposed equations have less severe approximations and often provide results which compare favorably to molecular dynamics simulation where other methods fail.
Coulomb breakup of neutron-rich 29,30Na isotopes near the island of inversion
NASA Astrophysics Data System (ADS)
Rahaman, A.; Datta, Ushasi; Aumann, T.; Beceiro-Novo, S.; Boretzky, K.; Caesar, C.; Carlson, B. V.; Catford, W. N.; Chakraborty, S.; Chartier, M.; Cortina-Gil, D.; De Angelis, G.; Diaz Fernandez, P.; Emling, H.; Ershova, O.; Fraile, L. M.; Geissel, H.; Gonzalez-Diaz, D.; Johansson, H.; Jonson, B.; Kalantar-Nayestanaki, N.; Kröll, T.; Krücken, R.; Kurcewicz, J.; Langer, C.; Le Bleis, T.; Leifels, Y.; Marganiec, J.; Münzenberg, G.; Najafi, M. A.; Nilsson, T.; Nociforo, C.; Panin, V.; Paschalis, S.; Plag, R.; Reifarth, R.; Ricciardi, M. V.; Rigollet, C.; Rossi, D.; Scheidenberger, C.; Scheit, H.; Simon, H.; Taylor, J. T.; Togano, Y.; Typel, S.; Volkov, V.; Wagner, A.; Wamers, F.; Weick, H.; Weigand, M.; Winfield, J. S.; Yakorev, D.; Zoric, M.
2017-04-01
First results are reported on the ground state configurations of the neutron-rich 29,30Na isotopes, obtained via Coulomb dissociation (CD) measurements. The invariant mass spectra of these nuclei have been obtained through measurement of the four-momenta of all decay products after Coulomb excitation of those nuclei on a 208Pb target at energies of 400–430 MeV/nucleon using the FRS-ALADIN-LAND setup at GSI, Darmstadt. Integrated inclusive CD cross-sections (CD) of 89 (7) mb and 167 (13) mb for one neutron removal from 29Na and 30Na, respectively, have been extracted up to an excitation energy of 10 MeV. The major part of one neutron removal, CD cross-sections of those nuclei populate the core, in its ground state. A comparison with the direct breakup model, suggests the predominant occupation of the valence neutron in the ground state of 29Na (3/{2}+) and 30Na ({2}+) is the d-orbital with a small contribution from the s-orbital, which are coupled with the ground state of the core. One of the major components of the ground state configurations of these nuclei are 28Na{}{gs}({1}+)\\otimes {ν }s,d and 29Na{}{gs}(3/{2}+)\\otimes {ν }s,d, respectively. The ground state spin and parity of these nuclei obtained from this experiment are in agreement with earlier reported values. The spectroscopic factors for the valence neutron occupying the s and d orbitals for these nuclei in the ground state have been extracted and reported for the first time. A comparison of the experimental findings with shell model calculation using the MCSM suggests a lower limit of around 4.3 MeV of the sd–pf shell gap in 30Na.
NASA Astrophysics Data System (ADS)
Carbotte, S. M.; Ferrini, V.; Arko, R. A.; Chandler, C. L.; Maffei, A. R.; Miller, S. P.; Stocks, K.; Smith, S. R.; Bourassa, M. A.
2009-12-01
for quality assessment of high priority underway data types, to provide feedback to operators on data quality and integrity. The R2R project plan is to leverage and augment the existing centralized information resources of the UNOLS office, ship operators, and National Data Centers to facilitate the documentation and delivery of oceanographic data from “rolling deck” to “repository.”
Interatomic Coulombic decay widths of helium trimer: Ab initio calculations
Kolorenč, Přemysl; Sisourat, Nicolas
2015-12-14
We report on an extensive study of interatomic Coulombic decay (ICD) widths in helium trimer computed using a fully ab initio method based on the Fano theory of resonances. Algebraic diagrammatic construction for one-particle Green’s function is utilized for the solution of the many-electron problem. An advanced and universal approach to partitioning of the configuration space into discrete states and continuum subspaces is described and employed. Total decay widths are presented for all ICD-active states of the trimer characterized by one-site ionization and additional excitation of an electron into the second shell. Selected partial decay widths are analyzed in detail, showing how three-body effects can qualitatively change the character of certain relaxation transitions. Previously unreported type of three-electron decay processes is identified in one class of the metastable states.
Coulomb-stable triply charged diatomic: HeY3+
NASA Astrophysics Data System (ADS)
Wesendrup, Ralf; Pernpointner, Markus; Schwerdtfeger, Peter
1999-11-01
Accurate relativistic coupled-cluster calculations show that the triply charged species HeY3+ is a stable molecule and represents the lightest diatomic trication that does not undergo a Coulomb fragmentation into charged fragments. The diatomic potential-energy curve is approximated by an extended Morse potential, and vibrational-rotational constants for HeY3+ are predicted (Re=224.3 pm, D0=0.394 eV, ωe=437 cm-1, ωexe=15.8 cm-1, Be=0.877 cm-1). It is further shown that the He-Y3+ bond can basically be described as a charge-induced dipole interaction.
Strong nuclear couplings as a source of Coulomb rainbow suppression
Keeley, N.; Alamanos, N.; Rusek, K.
2010-09-15
A recent measurement of the {sup 11}Be+{sup 64}Zn quasielastic scattering angular distribution exhibits a non-Fresnel-type pattern, in contrast to {sup 6}He+{sup 64}Zn elastic scattering but similar to that for the elastic scattering of {sup 6}He from heavy targets. We show by means of continuum discretized coupled-channels (CDCC) calculations that this unusual behavior of {sup 11}Be is caused by the much greater importance of nuclear coupling to the continuum in {sup 11}Be compared to {sup 6}He, where Coulomb dipole coupling is mainly responsible for the non-Fresnel-like shape, when present. We also show that the dynamic polarization potentials derived from the CDCC calculations seem to follow a universal form as a function of radius.
Coulomb gauge confinement in the heavy quark limit
Popovici, C.; Watson, P.; Reinhardt, H.
2010-05-15
The relationship between the nonperturbative Green's functions of Yang-Mills theory and the confinement potential is investigated. By rewriting the generating functional of quantum chromodynamics in terms of a heavy quark mass expansion in Coulomb gauge, restricting to leading order in this expansion and considering only the two-point functions of the Yang-Mills sector, the rainbow-ladder approximation to the gap and Bethe-Salpeter equations is shown to be exact in this case and an analytic, nonperturbative solution is presented. It is found that there is a direct connection between the string tension and the temporal gluon propagator. Further, it is shown that for the 4-point quark correlation functions, only confined bound states of color-singlet quark-antiquark (meson) and quark-quark (baryon) pairs exist.
Slow Interatomic Coulombic Decay of Multiply Excited Neon Clusters
NASA Astrophysics Data System (ADS)
Iablonskyi, D.; Nagaya, K.; Fukuzawa, H.; Motomura, K.; Kumagai, Y.; Mondal, S.; Tachibana, T.; Takanashi, T.; Nishiyama, T.; Matsunami, K.; Johnsson, P.; Piseri, P.; Sansone, G.; Dubrouil, A.; Reduzzi, M.; Carpeggiani, P.; Vozzi, C.; Devetta, M.; Negro, M.; Calegari, F.; Trabattoni, A.; Castrovilli, M. C.; Faccialà, D.; Ovcharenko, Y.; Möller, T.; Mudrich, M.; Stienkemeier, F.; Coreno, M.; Alagia, M.; Schütte, B.; Berrah, N.; Kuleff, A. I.; Jabbari, G.; Callegari, C.; Plekan, O.; Finetti, P.; Spezzani, C.; Ferrari, E.; Allaria, E.; Penco, G.; Serpico, C.; De Ninno, G.; Nikolov, I.; Diviacco, B.; Di Mitri, S.; Giannessi, L.; Prince, K. C.; Ueda, K.
2016-12-01
Ne clusters (˜5000 atoms ) were resonantly excited (2 p →3 s ) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.
Gribov pendulum in the Coulomb gauge on curved spaces
NASA Astrophysics Data System (ADS)
Canfora, Fabrizio; Giacomini, Alex; Oliva, Julio
2011-11-01
In this paper the generalization of the Gribov pendulum equation in the Coulomb gauge for curved space-times is analyzed on static spherically symmetric backgrounds. A rigorous argument for the existence and uniqueness of solution is provided in the asymptotically AdS case. The analysis of the strong and weak boundary conditions is equivalent to analyzing an effective one-dimensional Schrödinger equation. Necessary conditions in order for spherically symmetric backgrounds to admit solutions of the Gribov pendulum equation representing copies of the vacuum satisfying the strong boundary conditions are given. It is shown that asymptotically flat backgrounds do not support solutions of the Gribov pendulum equation of this type, while on asymptotically AdS backgrounds such ambiguities can appear. Some physical consequences are discussed.
Finsler-type modification of the Coulomb law
NASA Astrophysics Data System (ADS)
Itin, Yakov; Lämmerzahl, Claus; Perlick, Volker
2014-12-01
Finsler geometry is a natural generalization of pseudo-Riemannian geometry. It can be motivated e.g. by a modified version of the Ehlers-Pirani-Schild axiomatic approach to space-time theory. Also, some scenarios of quantum gravity suggest a modified dispersion relation which could be phrased in terms of Finsler geometry. On a Finslerian space-time, the universality of free fall is still satisfied but local Lorentz invariance is violated in a way not covered by standard Lorentz invariance violation schemes. In this paper we consider a Finslerian modification of Maxwell's equations. The corrections to the Coulomb potential and to the hydrogen energy levels are computed. We find that the Finsler metric corrections yield a splitting of the energy levels. Experimental data provide bounds for the Finsler parameters.
Coulomb-blockade and Pauli-blockade magnetometry
NASA Astrophysics Data System (ADS)
Széchenyi, Gábor; Pályi, András
2017-01-01
Scanning-probe magnetometry is a valuable experimental tool to investigate magnetic phenomena at the micro- and nanoscale. We theoretically analyze the possibility of measuring magnetic fields via the electrical current flowing through quantum dots. We characterize the shot-noise-limited magnetic-field sensitivity of two devices: a single dot in the Coulomb blockade regime, and a double dot in the Pauli blockade regime. Constructing such magnetometers using carbon nanotube quantum dots would benefit from the large, strongly anisotropic and controllable g tensors, the low abundance of nuclear spins, and the small detection volume allowing for nanoscale spatial resolution; we estimate that a sensitivity below 1 μ T/√{Hz} can be achieved with this material. As quantum dots have already proven to be useful as scanning-probe electrometers, our proposal highlights their potential as hybrid sensors having in situ switching capability between electrical and magnetic sensing.
Classical Kepler-Coulomb problem on SO(2, 2) hyperboloid
Petrosyan, D. Pogosyan, G. S.
2013-10-15
In the present work, the problem of the motion of the classical particle in the Kepler-Coulomb field in three-dimensional hyperbolic space H{sub 2}{sup 2}: z{sub 2}{sup 0} + z{sub 2}{sup 1} - z{sub 2}{sup 2} - z{sub 2}{sup 3} = R{sup 2} is solved in the framework of Hamilton-Jacobi equation. The requirements for the existence of bounded motion of particle are formulated. The equation of the trajectory of particle is obtained, and it is shown that all the finite trajectories are closed. It is also demonstrated that under the certain values (zero or negative) of the separation constant A the fall of the particle onto the center takes place.
Ultra-high-ohmic microstripline resistors for Coulomb blockade devices
NASA Astrophysics Data System (ADS)
Lotkhov, Sergey V.
2013-06-01
In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ˜ 20 mK for films with sheet resistivities as high as ˜7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current.
Ultra-high-ohmic microstripline resistors for Coulomb blockade devices.
Lotkhov, Sergey V
2013-06-14
In this paper, we report on the fabrication and low-temperature characterization of ultra-high-ohmic microstripline resistors made of a thin film of weakly oxidized titanium. Nearly linear voltage-current characteristics were measured at temperatures down to T ~ 20 mK for films with sheet resistivities as high as ~7 kΩ, i.e. about an order of magnitude higher than our previous findings for weakly oxidized Cr. Our analysis indicates that such an improvement can help to create an advantageous high-impedance environment for different Coulomb blockade devices. Further properties of the Ti film addressed in this work show the promise of low-noise behavior of the resistors when applied in different realizations of the quantum standard of current.
Relativistic Aharonov{endash}Bohm{endash}Coulomb problem
Hagen, C.R.; Park, D.K.
1996-10-01
The ((2+1)-dimensional) Aharonov{endash}Bohm effect is analyzed for a spin-1/2 particle in the case that a 1/{ital r} potential is present. Scalar and vector couplings are each considered. It is found that the approach in which the flux tube is given a finite radius that is taken to zero only after a matching of boundary conditions does not give physically meaningful results. Specifically, the operations of taking the limit of zero flux tube radius and the Galilean limit do not commute. Thus there appears to be no satisfactory solution of the relativistic Aharonov{endash}Bohm{endash}Coulomb problem using the finite radius flux tube method. Copyright {copyright} 1996 Academic Press, Inc.
Configurational and energy landscape in one-dimensional Coulomb systems
NASA Astrophysics Data System (ADS)
Varela, Lucas; Téllez, Gabriel; Trizac, Emmanuel
2017-02-01
We study a one-dimensional Coulomb system, where two charged colloids are neutralized by a collection of point counterions, with global neutrality. With temperature being given, two situations are addressed: Either the colloids are kept at fixed positions (canonical ensemble) or the force acting on the colloids is fixed (isobaric-isothermal ensemble). The corresponding partition functions are worked out exactly, in view of determining which arrangement of counterions is optimal. How many counterions should be in the confined segment between the colloids? For the remaining ions outside, is there a left-right symmetry breakdown? We evidence a cascade of transitions as system size is varied in the canonical treatment or as pressure is increased in the isobaric formulation.
Coulomb Excitation of the N = 50 nucleus 80Zn
NASA Astrophysics Data System (ADS)
van de Walle, J.; Aksouh, F.; Ames, F.; Behrens, T.; Bildstein, V.; Blazhev, A.; Cederkäll, J.; Clément, E.; Cocolios, T. E.; Davinson, T.; Delahaye, P.; Eberth, J.; Ekström, A.; Fedorov, D. V.; Fedosseev, V. N.; Fraile, L. M.; Franchoo, S.; Gernhauser, R.; Georgiev, G.; Habs, D.; Heyde, K.; Huber, G.; Huyse, M.; Ibrahim, F.; Ivanov, O.; Iwanicki, J.; Jolie, J.; Kester, O.; Köster, U.; Kröll, T.; Krücken, R.; Lauer, M.; Lisetskiy, A. F.; Lutter, R.; Marsh, B. A.; Mayet, P.; Niedermaier, O.; Nilsson, T.; Pantea, M.; Perru, O.; Raabe, R.; Reiter, P.; Sawicka, M.; Scheit, H.; Schrieder, G.; Schwalm, D.; Seliverstov, M. D.; Sieber, T.; Sletten, G.; Smirnova, N.; Stanoiu, M.; Stefanescu, I.; Thomas, J.-C.; Valiente-Dobón, J. J.; van Duppen, P.; Verney, D.; Voulot, D.; Warr, N.; Weisshaar, D.; Wenander, F.; Wolf, B. H.; Zielińska, M.
2008-05-01
Neutron rich Zinc isotopes, including the N = 50 nucleus 80Zn, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2+ states. For the first time, an excited state in 80Zn was observed and the 21+ state in 78Zn was established. The measured B(E2,21+-->01+) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N = 50 isotones indicate a good N = 50 shell closure and a strong Z = 28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus 78Ni.
Configurational and energy landscape in one-dimensional Coulomb systems.
Varela, Lucas; Téllez, Gabriel; Trizac, Emmanuel
2017-02-01
We study a one-dimensional Coulomb system, where two charged colloids are neutralized by a collection of point counterions, with global neutrality. With temperature being given, two situations are addressed: Either the colloids are kept at fixed positions (canonical ensemble) or the force acting on the colloids is fixed (isobaric-isothermal ensemble). The corresponding partition functions are worked out exactly, in view of determining which arrangement of counterions is optimal. How many counterions should be in the confined segment between the colloids? For the remaining ions outside, is there a left-right symmetry breakdown? We evidence a cascade of transitions as system size is varied in the canonical treatment or as pressure is increased in the isobaric formulation.
Anomalous Coulomb drag in bilayer graphene double layers
NASA Astrophysics Data System (ADS)
Liu, Xiaomeng; Taniguchi, Takashi; Watanabe, Kenji; Kim, Philip
Bilayer graphene double-layer structure consists of two layers of bilayer graphene separated by atomically thin hexagonal boron nitride (hBN). With a perfect Fermi surface nesting and strong electron-electron interaction (ECoulomb > Ekinetic), such systems offer exciting platforms to study interaction driven phenomena, such as Coulomb drag and exciton condensation. We fabricate ultra-clean encapsulated bilayer graphene double layers with dry pick-up method. Room temperature drag measurement on our devices shows the sign of drag agree with the typical Fermi liquid behavior. However, at lower temperatures, the sign of drag reversed, indicating a new drag mechanism emerges and dominates. We measure this with different geometry, temperature, bias and gating to investigate the origin of such effect and discuss the implication of the drag sign changes.
Dynamic stresses, coulomb failure, and remote triggering: corrected
Hill, David P.
2012-01-01
Dynamic stresses associated with crustal surface waves with 15–30 s periods and peak amplitudes <1 MPa are capable of triggering seismicity at sites remote from the generating mainshock under appropriate conditions. Coulomb failure models based on a frictional strength threshold offer one explanation for instances of rapid‐onset triggered seismicity that develop during the surface‐wave peak dynamic stressing. Evaluation of the triggering potential of surface‐wave dynamic stresses acting on critically stressed faults using a Mohr’s circle representation together with the Coulomb failure criteria indicates that Love waves should have a higher triggering potential than Rayleigh waves for most fault orientations and wave incidence angles. That (1) the onset of triggered seismicity often appears to begin during the Rayleigh wave rather than the earlier arriving Love wave, and (2) Love‐wave amplitudes typically exceed those for Rayleigh waves suggests that the explanation for rapid‐onset dynamic triggering may not reside solely with a simple static‐threshold friction mode. The results also indicate that normal faults should be more susceptible to dynamic triggering by 20‐s Rayleigh‐wave stresses than thrust faults in the shallow seismogenic crust (<10 km) while the advantage tips in favor of reverse faults greater depths. This transition depth scales with wavelength and coincides roughly with the transition from retrograde‐to‐prograde particle motion. Locally elevated pore pressures may have a role in the observed prevalence of dynamic triggering in extensional regimes and geothermal/volcanic systems. The result is consistent with the apparent elevated susceptibility of extensional or transtensional tectonic regimes to remote triggering by Rayleigh‐wave dynamic stresses than compressional or transpressional regimes.
Three-body Coulomb systems using generalized angular-momentum S states
NASA Technical Reports Server (NTRS)
Whitten, R. C.; Sims, J. S.
1974-01-01
An expansion of the three-body Coulomb potential in generalized angular-momentum eigenfunctions developed earlier by one of the authors is used to compute energy eigenvalues and eigenfunctions of bound S states of three-body Coulomb systems. The results for He, H(-), e(-)e(+)e(-), and pmu(-)p are compared with the results of other computational approaches.
First-principles calculations of shear moduli for Monte Carlo-simulated Coulomb solids
NASA Technical Reports Server (NTRS)
Ogata, Shuji; Ichimaru, Setsuo
1990-01-01
The paper presents a first-principles study of the shear modulus tensor for perfect and imperfect Coulomb solids. Allowance is made for the effects of thermal fluctuations for temperatures up to the melting conditions. The present theory treats the cases of the long-range Coulomb interaction, where volume fluctuations should be avoided in the Ewald sums.
Coulomb-corrected eikonal description of the breakup of halo nuclei
Capel, P.; Baye, D.
2008-11-15
The eikonal description of breakup reactions diverges because of the Coulomb interaction between the projectile and the target. This divergence is due to the adiabatic, or sudden, approximation usually made, which is incompatible with the infinite range of the Coulomb interaction. A correction for this divergence is analyzed by comparison with the dynamical eikonal approximation, which is derived without the adiabatic approximation. The correction consists in replacing the first-order term of the eikonal Coulomb phase by the first-order of the perturbation theory. This allows taking into account both nuclear and Coulomb interactions on the same footing within the computationally efficient eikonal model. Excellent results are found for the dissociation of {sup 11}Be on lead at 69 MeV/nucleon. This Coulomb-corrected eikonal approximation provides a competitive alternative to more elaborate reaction models for investigating breakup of three-body projectiles at intermediate and high energies.
Resonance tuning due to Coulomb interaction in strong near-field coupled metamaterials
Roy Chowdhury, Dibakar; Xu, Ningning; Zhang, Weili; Singh, Ranjan
2015-07-14
Coulomb's law is one of the most fundamental laws of physics that describes the electrostatic interaction between two like or unlike point charges. Here, we experimentally observe a strong effect of Coulomb interaction in tightly coupled terahertz metamaterials where the split-ring resonator dimers in a unit cell are coupled through their near fields across the capacitive split gaps. Using a simple analytical model, we evaluated the Coulomb parameter that switched its sign from negative to positive values indicating the transition in the nature of Coulomb force from being repulsive to attractive depending upon the near field coupling between the split ring resonators. Apart from showing interesting effects in the strong coupling regime between meta-atoms, Coulomb interaction also allows an additional degree of freedom to achieve frequency tunable dynamic metamaterials.
Interatomic and intermolecular Coulombic decay: the coming of age story
NASA Astrophysics Data System (ADS)
Jahnke, T.
2015-04-01
In pioneering work by Cederbaum et al an excitation mechanism was proposed that occurs only in loosely bound matter (Cederbaum et al 1997 Phys. Rev. Lett. 79 4778): it turned out, that (in particular) in cases where a local Auger decay is energetically forbidden, an excited atom or molecule is able to decay in a scheme which was termed ‘interatomic Coulombic decay’ (or ‘intermolecular Coulombic decay’) (ICD). As ICD occurs, the excitation energy is released by transferring it to an atomic or molecular neighbor of the initially excited particle. As a consequence the neighboring atom or molecule is ionized as it receives the energy. A few years later the existence of ICD was confirmed experimentally (Marburger et al 2003 Phys. Rev. Lett. 90 203401; Jahnke et al 2004 Phys. Rev. Lett. 93 163401; Öhrwall et al 2004 Phys. Rev. Lett. 93 173401) by different techniques. Since this time it has been found that ICD is not (as initially suspected) an exotic feature of van der Waals or hydrogen bonded systems, but that ICD is a very general and common feature occurring after a manifold of excitation schemes and in numerous weakly bound systems, as revealed by more than 200 publications. It was even demonstrated, that ICD can become more efficient than a local Auger decay in some system. This review will concentrate on recent experimental investigations on ICD. It will briefly introduce the phenomenon and give a short summary of the ‘early years’ of ICD (a detailed view on this episode of investigations can be found in the review article by U Hergenhahn with the same title (Hergenhahn 2011 J. Electron Spectrosc. Relat. Phenom. 184 78)). More recent articles will be presented that investigate the relevance of ICD in biological systems and possible radiation damage of such systems due to ICD. The occurrence of ICD and ICD-like processes after different excitation schemes and in different systems is covered in the middle section: in that context the helium dimer (He2
Ryan, Christopher M; Souda, Puneet; Bassilian, Sara; Ujwal, Rachna; Zhang, Jun; Abramson, Jeff; Ping, Peipei; Durazo, Armando; Bowie, James U; Hasan, S Saif; Baniulis, Danas; Cramer, William A; Faull, Kym F; Whitelegge, Julian P
2010-05-01
Integral membrane proteins remain a challenge to proteomics because they contain domains with physicochemical properties poorly suited to today's bottom-up protocols. These transmembrane regions may potentially contain post-translational modifications of functional significance, and thus development of protocols for improved coverage in these domains is important. One way to achieve this goal is by using top-down mass spectrometry whereby the intact protein is subjected to mass spectrometry and dissociation. Here we describe top-down high resolution Fourier transform mass spectrometry with collisionally activated dissociation to study post-translationally modified integral membrane proteins with polyhelix bundle and transmembrane porin motifs and molecular masses up to 35 kDa. On-line LC-MS analysis of the bacteriorhodopsin holoprotein yielded b- and y-ions that covered the full sequence of the protein and cleaved 79 of 247 peptide bonds (32%). The experiment proved that the mature sequence consists of residues 14-261, confirming N-terminal propeptide cleavage and conversion of N-terminal Gln-14 to pyrrolidone carboxylic acid (-17.02 Da) and C-terminal removal of Asp-262. Collisionally activated dissociation fragments localized the N(6)-(retinylidene) modification (266.20 Da) between residues 225-248 at Lys-229, the sole available amine in this stretch. Off-line nanospray of all eight subunits of the cytochrome b(6)f complex from the cyanobacterium Nostoc PCC 7120 defined various post-translational modifications, including covalently attached c-hemes (615.17 Da) on cytochromes f and b. Analysis of murine mitochondrial voltage-dependent anion channel established the amenability of the transmembrane beta-barrel to top-down MS and localized a modification site of the inhibitor Ro 68-3400 at Cys-232. Where neutral loss of the modification is a factor, only product ions that carry the modification should be used to assign its position. Although bond cleavage in some
Benessaiah, Karina; Sengupta, Raja
2014-08-01
Ecosystem-based approaches to aquaculture integrate environmental concerns into planning. Social-ecological systems research can improve this approach by explicitly relating ecological and social dynamics of change at multiple scales. Doing so requires not only addressing direct effects of aquaculture but also considering indirect factors such as changes in livelihood strategies, governance dynamics, and power relations. We selected the community of Puerto Morazán, Nicaragua as a case study to demonstrate how the introduction of small-scale aquaculture radically transformed another key livelihood activity, lagoon shrimp fishing, and the effects that these changes have had on lagoons and the people that depend on them. We find that shrimp aquaculture played a key role in the collapse, in the 1990s, of an existing lagoon common-property management. Shrimp aquaculture-related capital enabled the adoption of a new fishing technique that not only degraded lagoons but also led to their gradual privatization. The existence of social ties between small-scale shrimp farmers and other community members mitigated the impacts of privatization, illustrating the importance of social capital. Since 2008, community members are seeking to communally manage the lagoons once again, in response to degraded environmental conditions and a consolidation of the shrimp industry at the expense of smaller actors. This research shows that shrimp aquaculture intersects with a complex set of drivers, affecting not only how ecosystems are managed but also how they are perceived and valued. Understanding these social-ecological dynamics is essential to implement realistic policies and management of mangrove ecosystems and address the needs of resource-dependent people.
NASA Astrophysics Data System (ADS)
Benessaiah, Karina; Sengupta, Raja
2014-08-01
Ecosystem-based approaches to aquaculture integrate environmental concerns into planning. Social-ecological systems research can improve this approach by explicitly relating ecological and social dynamics of change at multiple scales. Doing so requires not only addressing direct effects of aquaculture but also considering indirect factors such as changes in livelihood strategies, governance dynamics, and power relations. We selected the community of Puerto Morazán, Nicaragua as a case study to demonstrate how the introduction of small-scale aquaculture radically transformed another key livelihood activity, lagoon shrimp fishing, and the effects that these changes have had on lagoons and the people that depend on them. We find that shrimp aquaculture played a key role in the collapse, in the 1990s, of an existing lagoon common-property management. Shrimp aquaculture-related capital enabled the adoption of a new fishing technique that not only degraded lagoons but also led to their gradual privatization. The existence of social ties between small-scale shrimp farmers and other community members mitigated the impacts of privatization, illustrating the importance of social capital. Since 2008, community members are seeking to communally manage the lagoons once again, in response to degraded environmental conditions and a consolidation of the shrimp industry at the expense of smaller actors. This research shows that shrimp aquaculture intersects with a complex set of drivers, affecting not only how ecosystems are managed but also how they are perceived and valued. Understanding these social-ecological dynamics is essential to implement realistic policies and management of mangrove ecosystems and address the needs of resource-dependent people.
Effects of Coulomb quadrupole excitation in heavy-ion reactions
NASA Astrophysics Data System (ADS)
Cheoun, Myung-Ki; Choi, K. S.; Kim, K. S.; Kim, T. H.; So, W. Y.
2016-09-01
For 12C + 184W, 18O + 184W, and 20Ne + 208Pb systems, we investigate the suppression of the ratios P E = σ el/ σ RU by using the Coulomb quadrupole excitation (CQE) potentials. In order to explain the effect of the CQE potentials, we first use a well-known Love's CQE potential, and reproduce the experimental P E data well by using this potential. We also introduce a simple CQE potential written as W CQE( r) = - W P / r n , which is much simpler than the conventional Love's potential, to investigate the suppression of the P E ratios. Using this potential, we perform a χ2 analysis to find the adjustable parameter n, then, we find that the best fit parameters n ≈ 5 is close to the lowest order term, 1/ r 5. Consequently, we find that using the simple CQE potential explains the experimental P E data and that the ratio P E depends on the n values sensitively.
Le probleme quantique bicomplexe du potentiel de Coulomb
NASA Astrophysics Data System (ADS)
Mathieu, Jeremie
In this master's thesis, is gathered a great part of my work on bicomplex quantum mechanics. Bicomplex numbers are the second order multicomplex generalization of complex numbers. Equipped with the standard addition and multiplication, they form an algebraic structure called a commutative ring with unity and are one of many known generalizations of the real number system. It has been almost eighty years since it's been proposed to use an algebra of a superior dimension than the one of complex numbers to construct the mathematical formalism of quantum mechanics. However it's only been since less than a decade ago that the idea of using the bicomplex numbers to do so has been seriously considered. In that sense, the complete resolution of the quantum harmonic oscillator in a bicomplex Hilbert space was the first major achievement of this ambitious project. This thesis, by article style, is a continuation of this work of generalization. It presents, by an axiomatic approach, the complete differential solution of the bicomplex quantum Coulomb potential problem and half of its algebraic solution.
Coulomb drag and tunneling studies in quantum Hall bilayers
NASA Astrophysics Data System (ADS)
Nandi, Debaleena
The bilayer quantum Hall state at total filling factor νT=1, where the total electron density matches the degeneracy of the lowest Landau level, is a prominent example of Bose-Einstein condensation of excitons. A macroscopically ordered state is realized where an electron in one layer is tightly bound to a "hole" in the other layer. If exciton transport were the only bulk transportmechanism, a current driven in one layer would spontaneously generate a current of equal magnitude and opposite sign in the other layer. The Corbino Coulomb drag measurements presented in this thesis demonstrate precisely this phenomenon. Excitonic superfluidity has been long sought in the νT=1 state. The tunneling between the two electron gas layers exihibit a dc Josephson-like effect. A simple model of an over-damped voltage biased Josephson junction is in reasonable agreement with the observed tunneling I -- V. At small tunneling biases, it exhibits a tunneling "supercurrent". The dissipation is carefully studied in this tunneling "supercurrent" and found to remain small but finite.
The mystery of Coulomb friction in sediment transport
NASA Astrophysics Data System (ADS)
Pähtz, Thomas; Duran, Orencio
Nearly all analytical models of sediment transport in Newtonian fluid (e.g., air or water) are based on Bagnold's assumption of a constant Coulomb friction coefficient (particle-shear-pressure-ratio, μ) at the interface (zb) between sediment bed and transport layer. In fact, this assumption is the main reason why these models predict the sediment load (and subsequently the sediment transport rate) to be proportional to the excess shear stress (τ -τt), a scaling which has been confirmed in many wind-tunnel and flume experiments. Attempts to explain why μ (zb) is constant have usually been based on the sliding-friction analogy or rheology arguments. However, here we analytically derive μ (zs) √{ 3} - 1 , where zs is the location at which the production rate of particle fluctuation energy is maximal. Our derivation is based on the assumption that the rate of collisional transfer of horizontal into vertical kinetic energy is typically much larger than the rate of energy dissipation. Using state-of-the-art numerical simulations of sediment transport in Newtonian fluid, we validate all assumptions and approximation involved in our derivation. Interestingly, the location zs can significantly deviate from zb depending on the simulated conditions. We acknowledge support from grants National Natural Science Foundation of China (Nos. 1151101041 and 41376095) and Natural Science Foundation of Zhejiang Province (No. LR16E090001).
Three-body quantum Coulomb problem: Analytic continuation
NASA Astrophysics Data System (ADS)
Turbiner, A. V.; Lopez Vieyra, J. C.; Olivares Pilón, H.
2016-08-01
The second (unphysical) critical charge in the three-body quantum Coulomb system of a nucleus of positive charge Z and mass mp, and two electrons, predicted by Stillinger has been calculated to be equal to ZB∞ = 0.904854 and ZBmp = 0.905138 for infinite and finite (proton) mass mp, respectively. It is shown that in both cases, the ground state energy E(Z) (analytically continued beyond the first critical charge Zc, for which the ionization energy vanishes, to ReZ
Synchrotron and Coulomb Boiler in Cygnus X-1
Malzac, Julien; Belmont, Renaud
2009-05-11
We use a new code to simulate the radiation and kinetic processes in the X-ray emitting region around accreting black holes and constrain the magnetic field and temperature of the hot protons in the corona of Cygnus X-1. In the hard state we find a magnetic field below equipartition with radiation, suggesting that the corona is not powered through magnetic field dissipation (as assumed in most accretion disc corona models). On the other hand, our results also point toward proton temperatures that are substantially lower than typical temperatures of the ADAF models. Finally, we show that in both spectral states Comptonising plasma could be powered essentially through power-law acceleration of non-thermal electrons, which are then partly thermalised by the synchrotron and Coulomb boiler. This suggests that, contrary to current beliefs, the corona of the HSS and that of the LHS could be of very similar nature. The differences between the LHS and HSS coronal spectra would then be predominantly caused by the strong disc soft cooling emission which is present in the HSS and absent in the LHS.
The EBIS/T as a Coulomb target for ions
NASA Astrophysics Data System (ADS)
Becker, Reinard; Kester, Oliver
2004-01-01
A partially neutralised electron beam can be considered as a well defined target of ions. Trapped in the electrostatic 3D-trap of the electron beam in an EBIS, they will—for low loss rates—acquire an energy distribution according to Boltzmanns law. The resulting spatial distribution then is well defined, once the ion temperature and the amount of ions are known. Both are related to each other by a monotone dependence, hence determination of either the ion temperature or the number of ions will give the second quantity. Such a Coulomb target provides friction to the radial movement of newly injected ions, hence can be used to facilitate the trapping of low charged injected ions (external ion source, charge breeder) or of cooling of highly charged ions (created by deceleration). Due to the well known properties of such a target, it also may be used for collision studies between trapped ions and either a beam of atoms or of additionally injected ions.
Superallowed fermi beta decay and Coulomb mixing in nuclei
Hardy, J. C.; Towner, I. S.
1999-09-02
Superallowed 0{sup +}{yields}0{sup +} nuclear beta decay provides a direct measure of the weak vector coupling constant, G{sub v}. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of {sup 10}C to that of {sup 54}Co, and demonstrate that the results confirm conservation of the weak vector current (CVC) but differ at the 98% confidence level from the unitarity condition for the Cabibbo-Kobayashi-Maskawa (CKM) matrix. We examine the reliability of the small calculated corrections that have been applied to the data, and conclude that there are no evident defects although the Coulomb correction, {delta}{sub C}, depends sensitively on nuclear structure and thus needs to be constrained independently. The potential importance of a result in disagreement with unitarity, clearly indicates the need for further work to confirm or deny the discrepancy. We examine the options and recommend priorities for new experiments and improved calculations. Some of the required experiments depend upon the availability of intense radioactive beams. Others are possible with existing facilities. (c) 1999 American Institute of Physics.
A molecular dynamics model for the Coulomb explosion
NASA Astrophysics Data System (ADS)
Smith, Roger; Ramasawmy, D.; Kenny, S. D.
2005-01-01
The impact of positively charged Arn+ ions, n = 1, 4, 8, incident normally on the (1 0 0) surface of NaCl is studied by Molecular Dynamics (MD) simulations for energies up to 1 keV. The model assumes fixed charges on the ions and the effect of projectile charge is investigated as a function of energy. It is shown that there is a significant enhancement in the sputtering yield at low impact energies due to the attachment of Cl ions to the impacting Ar, which is subsequently ejected from the lattice. The low energy Ar ions can also experience acceleration towards the NaCl crystal due to Coulombic attraction. At energies greater than a few hundred eV the Ar ions implant within the crystal which accommodates the extra charge from these ions. As a result the sputtering yield from the initial impact is reduced but as the dose increases, the yield rises as Na+ ions are preferentially ejected from the lattice. A large proportion of the ejected material is in the form of clusters.
Dust-Coulomb waves in dense dusty plasmas
NASA Astrophysics Data System (ADS)
Rao, N. N.
1999-12-01
Dusty plasmas can be considered as tenuous, dilute or dense when the dust fugacity parameter f≡4πnd0λD2R˜NDR/λD satisfies f≪1, ˜1, or ≫1, where nd0, λD and R denote, respectively, the dust number density, the plasma Debye length and the dust grain size (radius), and ND=nd0λD3 is the dust plasma parameter. Dense dusty plasmas are shown to support a new kind of ultra low-frequency electrostatic dust mode which may be called the "Dust-Coulomb Wave" (DCW). In contrast to the dust-acoustic wave (DAW) and the dust-lattice wave (DLW) which exist even for constant grain charge, DCWs are accompanied by dust charge as well as number density perturbations which are proportional to each other. For frequencies much smaller than the grain charging frequency, DCWs propagate as normal modes with the phase speed CDC≡qd0/√mdR , where qd0 (md) is the charge (mass) of the dust grains. In the long wavelength limit, the DCW phase speed is much smaller than that of DAW (CDA), and scales as ˜CDA/√f . Thus, for a given wave number, the frequency regime for the existence of DCW is much lower than the DAW regime. A comparison between the three types of dust-modes (DCWs, DAWs, and DLWs) has been carried out.
Coulomb Excitation of Radioactive Mo-Ru Isotopes
NASA Astrophysics Data System (ADS)
Allmond, J. M.; Gretina-Chico2 Collaboration
2016-09-01
The study of shapes in atomic nuclei has been a major focus of nuclear structure ever since the observation of large electric quadrupole moments in the first half of the 20th century. A leading challenge has been to experimentally establish regions of oblate deformation, which are very limited, and triaxial deformation. The neutron-rich Mo-Ru region is expected to exhibit triaxial deformation in the low-lying states, mediated by a relatively rare instance of prolate-to-oblate shape evolution. A survey of equipment, techniques, and preliminary results from recent Coulomb-excitation and beta-decay experiments in the neutron-rich Mo-Ru region will be presented. These experiments were conducted at the CARIBU-ANL facility using GRETINA-CHICO2. An emphasis will be placed on unique opportunities with 3-MeV/u beams. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics.
The onset of coulomb explosions in polyatomic molecules
Smith; Ledingham; Singhal; McCanny; Graham; Kilic; Tzallas; Kosmidis; Langley; Taday
1999-01-01
With the development of high intensity femtosecond lasers, the ionisation and dissociation dynamics of molecules has become an area of considerable interest. Using the technique of femtosecond laser mass spectrometry (FLMS), the molecules carbon disulphide, pyrimidine, toluene, cyclohexanone and benzaldehyde are studied with pulse widths of 50 fs in the near infrared (IR) wavelength region (790 nm). Results are presented and contrasted for laser beam intensities around 10(15) and 10(16) W cm(-2). For the lower intensities, the mass spectra yield dominant singly charged parent ions. Additionally, the appearance of doubly charged parent ions is evident for carbon disulphide, toluene and benzaldehyde with envelopes of doubly charged satellite species existing in these local regions. Carbon disulphide also reveals a small triply charged component. Such atomic-like features are thought to be a strong fingerprint of FLMS at these intensities. However, upon increasing the laser intensity to approximately 10(16) W cm(-2), parent ion dominance decreases and the appearance of multiply charged atomic species occurs, particularly carbon. This phenomenon has been attributed to Coulomb explosions in which the fast absorption of many photons may produce transient highly ionised parent species which can subsequently blow apart. Copyright 1999 John Wiley & Sons, Ltd.
Dark Coulomb binding of heavy neutrinos of fourth family
NASA Astrophysics Data System (ADS)
Belotsky, K. M.; Esipova, E. A.; Khlopov, M. Yu.; Laletin, M. N.
2015-11-01
Direct dark matter searches put severe constraints on the weakly interacting massive particles (WIMPs). These constraints cause serious troubles for the model of stable neutrino of fourth generation with mass around 50GeV. Though the calculations of primordial abundance of these particles make them in the charge symmetric case a sparse subdominant component of the modern dark matter, their presence in the universe would exceed the current upper limits by several orders of the magnitude. However, if quarks and leptons of fourth generation possess their own Coulomb-like y-interaction, recombination of pairs of heavy neutrinos and antineutrinos and their annihilation in the “neutrinium” atoms can play important role in their cosmological evolution, reducing their modern abundance far below the experimental upper limits. The model of stable fourth generation assumes that the dominant part of dark matter is explained by excessive Ū antiquarks, forming (ŪŪŪ)-- charged clusters, bound with primordial helium in nuclear-interacting O-helium (OHe) dark atoms. The y charge conservation implies generation of the same excess of fourth generation neutrinos, potentially dangerous WIMP component of this scenario. We show that due to y-interaction recombination of fourth neutrinos with OHe hides these WIMPs from direct WIMP searches, leaving the negligible fraction of free neutrinos, what makes their existence compatible with the experimental constraints.
A new graphene composite with a high coulombic efficiency
NASA Astrophysics Data System (ADS)
Protich, Z.; Wong, P.; Santhanam, K. S. V.
2016-11-01
Zinc-graphene composite has been electrolytically produced for the first time using a graphene quantum dot (GQD) electrode. The electrochemical reduction of zinc ion at a GQD electrode is shifted to a lesser negative potential with the complimentary anodic peak due to the oxidation of the composite shifted towards a positive potential as compared to zinc ion reduction in the GQD bath. The coulombic efficiency of the composite represents a gain of nearly 10% over the conventional Zn/Zn2+ in the energy storage systems. In galvanostatic electrolysis, the deposition of zinc-graphene composite is carried out under neutral and acidic conditions. The X-ray diffraction of the electrolytically prepared composite shows distinct features of 2 theta reflection at 8° due to (001) plane of graphene, in addition to the characteristic reflections at 38.9°,43.2°, 54.3°, 70.1° and 90° arising from Zn at (002), (100), (101), (102) and (110). A large scale preparation of the zinc-graphene composite has been achieved at a zinc plate as the working electrode in the GQD bath. The composite is stable up to 250 °C. Scanning electron microscopic (SEM) and energy dispersion X-ray analysis (EDAX) shows a string like structure with peaks for carbon and zinc in EDAX.
Liquid-gas phase transitions in a multicomponent nuclear system with Coulomb and surface effects
Lee, S. J.; Mekjian, A. Z.
2001-04-01
The liquid-gas phase transition is studied in a multicomponent nuclear system using a local Skyrme interaction with Coulomb and surface effects. Some features are qualitatively the same as the results of Mu''ller and Serot where a relativistic mean field was used without Coulomb and surface effects. Surface tension brings the coexistence binodal surface to lower pressure. The Coulomb interaction makes the binodal surface smaller and causes another pair of binodal points at low pressure and large proton fraction with fewer protons in the liquid phase and more protons in the gas phase.
Coulomb impurity effects on the zero-Landau level splitting of graphene on polar substrates
NASA Astrophysics Data System (ADS)
Xiao, Yao; Li, Wei-Ping; Li, Zhi-Qing; Wang, Zi-Wu
2017-04-01
We theoretically investigate the effects of the Coulomb impurity on the zero-Landau level splitting of graphene on different polar substrates basing on the Fröhlich polaron model, in which the polaron is formed due to the carriers-surface optical phonon coupling. We discuss the influence of Coulomb impurity on the zero-Landau level splitting in the case of weak and strong coupling limits. We find that the splitting energy can be varied in a large scale due to the Coulomb impurity, which provides the possible theoretical explanation for the experimental measurements regarding the energy gap opened and zero-Landau level splitting in Landau quantized graphene.
Large ion Coulomb crystals: A near-ideal medium for coupling optical cavity modes to matter
Dantan, A.; Albert, M.; Marler, J. P.; Herskind, P. F.; Drewsen, M.
2009-10-15
We present an investigation of the coherent coupling of various transverse field modes of an optical cavity to ion Coulomb crystals. The obtained experimental results, which include the demonstration of identical collective coupling rates for different transverse modes of a cavity field to ions in the same large Coulomb crystal, are in excellent agreement with theoretical predictions. The results furthermore suggest that Coulomb crystals in the future may serve as near-ideal media for high-fidelity multimode quantum information processing and communication purposes, including the generation and storage of single-photon qubits encoded in different transverse modes.
Nonlinear quantization of a degenerate charged Bose gas in an external Coulomb trap
Reinisch, Gilbert
2004-09-01
We consider a degenerate charged Bose-Coulomb gas populating several discrete stationary boson bound states that are located in a spherical-symmetrical central Coulombian potential. Each such state is defined, through appropriate boundary conditions and normalization, by a so-called 'nonlinear eigenstate' that is actually a solution of the coupled (linear) stationary Schroedinger-like Gross-Pitaevskii differential equation and the (nonlinear) Poisson equation. The corresponding eigenvalues allow us to define the energies of these degenerate boson states, much like the Koopmans orbital energy in atomic physics. This theory applies surprisingly well (compared with the corresponding Hartree-Fock results) to spherical-symmetrical s orbital states in atomic physics (i.e., bosonlike restricted orbital states where the additional spin degree of freedom is already integrated out). Finally the superposition of two such stationary nonlinear eigenstates is investigated and given a semiclassical physical significance similar to a Thomas-Fermi approach. The resulting concepts apply particularly well (namely within an average 1% error bar with respect to spectroscopic data) to the 1s{sup 2}-2s{sup 2} orbital states of the 3{<=}Z{<=}9 atomic subsystems.
Analysis of Periodically Varying Gear Mesh Systems with Coulomb Friction Using Floquet Theory
NASA Astrophysics Data System (ADS)
VAISHYA, M.; SINGH, R.
2001-06-01
This article presents a new analytical model of a gear pair with time varying mesh stiffness, viscous damping and sliding friction parameters. Unlike previous models, the excitation consists of three separate terms, namely the unloaded transmission error, time-invariant external torque and the periodically varying sliding friction force. A Coulomb friction model is considered using first a quasi-static mean transmitted load that is represented by the Meissner equation. Then, a truly dynamic force between gear teeth is described that leads to a triangular function, and after appropriate substitutions, this assumes the form of the Bessel equation of the one-third order. For the damped Meissner equation, the forced vibration response is found with the application of Floquet theory. Exact integrals are calculated for the state transition matrix in a piecewise manner, instead of using the Fourier series expansion, thus eliminating the mode truncation errors. From the state transition matrix, unstable zones are identified and the actual forced response of the system is found in terms of dynamic transmission error for these zones. With the aid of an example, the significance of sliding friction on system response and stability is examined. Finally, key advantages and the need for analytical methods are demonstrated for such systems.
NumSBT: A subroutine for calculating spherical Bessel transforms numerically
NASA Astrophysics Data System (ADS)
Talman, J. D.
2009-02-01
A previous subroutine, LSFBTR, for computing numerical spherical Bessel (Hankel) transforms is updated with several improvements and modifications. The procedure is applicable if the input radial function and the output transform are defined on logarithmic meshes and if the input function satisfies reasonable smoothness conditions. Important aspects of the procedure are that it is simply implemented with two successive applications of the fast Fourier transform, and it yields accurate results at very large values of the transform variable. Applications to the evaluation of overlap integrals and the Coulomb potential of multipolar charge distributions are described. Program summaryProgram title: NumSBT Catalogue identifier: AANZ_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AANZ_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 476 No. of bytes in distributed program, including test data, etc.: 4451 Distribution format: tar.gz Programming language: Fortran 90 Computer: Generic Operating system: Linux Classification: 4.6 Catalogue identifier of previous version: AANZ_v1_0 Journal reference of previous version: Comput. Phys. Comm. 30 (1983) 93 Does the new version supersede the previous version?: No Nature of problem: This program is a subroutine which, for a function defined numerically on a logarithmic mesh in the radial coordinate, generates the spherical Bessel, or Hankel, transform on a logarithmic mesh in the transform variable. Accurate results for large values of the transform variable are obtained, that would not be otherwise obtainable. Solution method: The program applies a procedure proposed by the author [1] that treats the problem as a convolution. The calculation then requires two applications of the fast Fourier transform method. Reasons for
Solution of two-body relativistic bound state equations with confining plus Coulomb interactions
NASA Technical Reports Server (NTRS)
Maung, Khin Maung; Kahana, David E.; Norbury, John W.
1992-01-01
Studies of meson spectroscopy have often employed a nonrelativistic Coulomb plus Linear Confining potential in position space. However, because the quarks in mesons move at an appreciable fraction of the speed of light, it is necessary to use a relativistic treatment of the bound state problem. Such a treatment is most easily carried out in momentum space. However, the position space Linear and Coulomb potentials lead to singular kernels in momentum space. Using a subtraction procedure we show how to remove these singularities exactly and thereby solve the Schroedinger equation in momentum space for all partial waves. Furthermore, we generalize the Linear and Coulomb potentials to relativistic kernels in four dimensional momentum space. Again we use a subtraction procedure to remove the relativistic singularities exactly for all partial waves. This enables us to solve three dimensional reductions of the Bethe-Salpeter equation. We solve six such equations for Coulomb plus Confining interactions for all partial waves.
Last, Isidore; Levy, Yaakov; Jortner, Joshua
2002-07-09
We address the stability of multicharged finite systems driven by Coulomb forces beyond the Rayleigh instability limit. Our exploration of the nuclear dynamics of heavily charged Morse clusters enabled us to vary the range of the pair potential and of the fissibility parameter, which results in distinct fragmentation patterns and in the angular distributions of the fragments. The Rayleigh instability limit separates between nearly binary (or tertiary) spatially unisotropic fission and spatially isotropic Coulomb explosion into a large number of small, ionic fragments. Implications are addressed for a broad spectrum of dynamics in chemical physics, radiation physics of ultracold gases, and biophysics, involving the fission of clusters and droplets, the realization of Coulomb explosion of molecular clusters, the isotropic expansion of optical molasses, and the Coulomb instability of "isolated" proteins.
Liu Jianye; Guo Wenjun; Gao Yuanyi; Xing Yongzhong; Li Xiguo
2004-09-01
We investigate separately the isospin effects of Coulomb interaction and symmetry potential on the dissipation and fragmentation in the intermediate energy heavy ion collisions by using isospin-dependent quantum molecular dynamics model. The calculated results show that the Coulomb interaction induces the reductions of both isospin fractionation ratio and nuclear stopping (momentum dissipation). However, the Coulomb interaction not only does not change obviously the strong isospin effect of the symmetry potential on the isospin fractionation ratio but also does not change obviously that of in-medium two-body collision on the nuclear stopping. On the contrary, the symmetry potential induces the enhancement of the isospin fractionation ratio but it is insensitive to the nuclear stopping. Finally, the competition between the Coulomb interaction and symmetry potential induces the reductions of both isospin fractionation ratio and nuclear stopping for two forms of symmetry potentials in this paper.
NASA Astrophysics Data System (ADS)
Hakobyan, Tigran; Nersessian, Armen; Shmavonyan, Hovhannes
2017-01-01
We propose a unified description for the constants of motion for superintegrable deformations of the oscillator and Coulomb systems on N -dimensional Euclidean space, sphere, and hyperboloid. We also consider the duality between these generalized systems and present some examples.
Capri, M.A.L. . E-mail: marcio@dft.if.uerj.br; Sobreiro, R.F. . E-mail: sobreiro@uerj.br; Sorella, S.P. . E-mail: sorella@uerj.br; Thibes, R. . E-mail: thibes@dft.if.uerj.br
2007-08-15
A detailed discussion of the renormalization properties of a class of gauges which interpolates among the Landau, Coulomb and maximal Abelian gauges is provided in the framework of the algebraic renormalization in Euclidean Yang-Mills theories in four dimensions.
Inversion of the circular averages transform using the Funk transform
NASA Astrophysics Data System (ADS)
Evren Yarman, Can; Yazıcı, Birsen
2011-06-01
The integral of a function defined on the half-plane along the semi-circles centered on the boundary of the half-plane is known as the circular averages transform. Circular averages transform arises in many tomographic image reconstruction problems. In particular, in synthetic aperture radar (SAR) when the transmitting and receiving antennas are colocated, the received signal is modeled as the integral of the ground reflectivity function of the illuminated scene over the intersection of spheres centered at the antenna location and the surface topography. When the surface topography is flat the received signal becomes the circular averages transform of the ground reflectivity function. Thus, SAR image formation requires inversion of the circular averages transform. Apart from SAR, circular averages transform also arises in thermo-acoustic tomography and sonar inverse problems. In this paper, we present a new inversion method for the circular averages transform using the Funk transform. For a function defined on the unit sphere, its Funk transform is given by the integrals of the function along the great circles. We used hyperbolic geometry to establish a diffeomorphism between the circular averages transform, hyperbolic x-ray and Funk transforms. The method is exact and numerically efficient when fast Fourier transforms over the sphere are used. We present numerical simulations to demonstrate the performance of the inversion method. Dedicated to Dennis Healy, a friend of Applied Mathematics and Engineering.
Cold chemistry with electronically excited Ca{sup +} Coulomb crystals
Gingell, Alexander D.; Bell, Martin T.; Oldham, James M.; Softley, Timothy P.; Harvey, Jeremy N.
2010-11-21
Rate constants for chemical reactions of laser-cooled Ca{sup +} ions and neutral polar molecules (CH{sub 3}F, CH{sub 2}F{sub 2}, or CH{sub 3}Cl) have been measured at low collision energies (
A mechanical connector design for high-current, high-coulomb pulsed power systems
Susoeff, A.R.; Hawke, R.S.; Leighton, K.S.
1992-02-25
A technique to make reliable high-current, high-coulomb electrical contact was developed for transmitting power into railguns. The method uses spring loaded removable connectors that are installed independently from the launcher. The simple rod-type design and absence of fastener holes allow maximum utilization of material mechanical properties. Repeated experiments with 9.5-mm diameter connectors demonstrated reliable pulsed charge transfer of 200 coulombs at currents of over 400kA. 20 refs.
Violation of detailed balance for charge-transfer statistics in Coulomb-blockade systems
NASA Astrophysics Data System (ADS)
Stegmann, Philipp; König, Jürgen
2017-03-01
We discuss the possibility to generate in Coulomb-blockade systems steady states that violate detailed balance. This includes both voltage biased and non-biased scenarios. The violation of detailed balance yields that the charge-transfer statistics for electrons tunneling into an island experiencing strong Coulomb interaction is different from the statistics for tunneling out. This can be experimentally tested by time-resolved measurement of the island's charge state. We demonstrate this claim for two model systems.
Solutions to the 1d Klein Gordon equation with cut-off Coulomb potentials
NASA Astrophysics Data System (ADS)
Hall, Richard L.
2007-12-01
In a recent paper by Barton [G. Barton, J. Phys. A: Math. Gen. 40 (2007) 1011], the 1-dimensional Klein Gordon equation was solved analytically for the non-singular Coulomb-like potential V(|x|)=-α/(|x|+a). In the present Letter, these results are completely confirmed by a numerical formulation that also allows a solution for an alternative cut-off Coulomb potential V(|x|)=-α/|x|, |x|>a, and otherwise V(|x|)=-α/a.
Ion Coulomb crystals: from quantum technology to chemistry close to the absolute zero point
NASA Astrophysics Data System (ADS)
Dulieu, O.; Willitsch, S.
2017-03-01
Ion Coulomb crystals are ordered structures of atomic or molecular ions stored in ion traps at temperatures close to the absolute zero point. These unusual "crystals" form the basis of extremely accurate clocks, provide an environment for precise studies of chemical reactions and enable advanced implementations of the technology for a quantum computer. In this article, we discuss the techniques for generating atomic and molecular Coulomb crystals and highlight some of their applications.
Three-Body Wave Functions in the Continuum: Application to the Repulsive Coulomb Case
NASA Astrophysics Data System (ADS)
Garrido, E.; Kievsky, A.; Viviani, M.
2017-03-01
In this work we describe a method that permits to obtain full three-body continuum wave functions regardless the short- or long-range character of the two-body potentials involved. Within this method all the possible incoming channels are automatically taken into account. When applied to systems where only the repulsive Coulomb interaction enters the method provides the corresponding regular three-body Coulomb functions, from which their irregular partners can be obtained.
Perturbed Coulomb potentials in the Klein-Gordon equation via the asymptotic iteration method
Barakat, T.
2009-03-15
The asymptotic iteration method is used to construct the exact energy eigenvalues for a Lorentz vector or a Lorentz scalar, and an equally mixed Lorentz vector and Lorentz scalar Coulombic potentials. Highly accurate and rapidly converging ground-state energies for Lorentz vector Coulomb with a Lorentz vector or a Lorentz scalar linear potential, V(r)=-{lambda}{sub 1}/r+krandV(r)=-{lambda}{sub 1}/randW(r)=kr, respectively, are obtained.
Comparing Mohr Coulomb and Drucker Prager function in three dimensional analysis on rock
NASA Astrophysics Data System (ADS)
Okay Aksoy, C.; Safak, Suleyman
2010-05-01
Rapid development is happening in the solution of engineering problems in recent years. The most important of all, develops in the area of computer software with no doubt. There are many programs that are finite element, finite different boundary element based. Some of these programmes use the Mohr-Coulomb failure criterion for the purpose of mining problems. This function is not very suitable in the solution of three dimension elasto-plastic problems. Mohr-Coulomb and Drucker-Prager functions are defined in a very similar manner. However, Mohr-Coulomb elastic-plastic model does not represent hardening behavior exhibited by most geologic materials and no yield under stress. On the other hand, Drucker-Prager plasticity model is an approximation of the Mohr-Coulomb failure criterion. Both, Mohr-Coulumb and Drucker-Prager fonctions have been analyzed with Gauss Elimination Method and Newton-Raphson Method, respectively and clearer results can be obtained by adopting the Drucker-Prager function to the Mohr-Coulomb function. Keywords: Drucker-Prager, Mohr-Coulomb, Rock Mechanics.
Coulomb-tail effect of electron-electron interaction on nonsequential double ionization
NASA Astrophysics Data System (ADS)
Zhou, Yueming; Huang, Cheng; Lu, Peixiang
2011-08-01
With the classical ensemble model, we investigate the manifestations of the Coulomb tail of electron-electron interaction in nonsequential double ionization by comparing the results from the short-range electron-electron interaction with those from the Coulombic electron-electron interaction. At the intensity below the recollision threshold, the two-electron momentum distributions in the direction parallel to the laser polarization show an anticorrelated behavior for the Coulombic electron-electron interaction while a correlated behavior for the short-range interaction, which indicates the responsibility of the Coulomb tail of the electron-electron interaction for the experimentally observed anticorrelated emission [Y. Liu, S. Tschuch, A. Rudenko, M. Durr, M. Siegel, U. Morgner, R. Moshammer, and J. Ullrich, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.101.053001 101, 053001 (2008)]. In the transverse direction, for the Coulombic electron-electron interaction, the two electrons exhibit no effect of repulsion at an intensity below the recollision threshold while a strong repulsion effect at an intensity above the threshold, which becomes weaker as the laser intensity further increases. Back analysis shows that the role of the Coulomb tail of electron-electron interaction leads asymmetric energy sharing (AES) to be prevalent at recollision. This AES results in the two electrons leaving the ion at different times or with different initial momenta, which is responsible for the anticorrelated behavior in the parallel direction and the intensity-dependent repulsion effect in the transverse direction.
Coulomb-tail effect of electron-electron interaction on nonsequential double ionization
Zhou Yueming; Huang Cheng; Lu Peixiang
2011-08-15
With the classical ensemble model, we investigate the manifestations of the Coulomb tail of electron-electron interaction in nonsequential double ionization by comparing the results from the short-range electron-electron interaction with those from the Coulombic electron-electron interaction. At the intensity below the recollision threshold, the two-electron momentum distributions in the direction parallel to the laser polarization show an anticorrelated behavior for the Coulombic electron-electron interaction while a correlated behavior for the short-range interaction, which indicates the responsibility of the Coulomb tail of the electron-electron interaction for the experimentally observed anticorrelated emission [Y. Liu, S. Tschuch, A. Rudenko, M. Durr, M. Siegel, U. Morgner, R. Moshammer, and J. Ullrich, Phys. Rev. Lett. 101, 053001 (2008)]. In the transverse direction, for the Coulombic electron-electron interaction, the two electrons exhibit no effect of repulsion at an intensity below the recollision threshold while a strong repulsion effect at an intensity above the threshold, which becomes weaker as the laser intensity further increases. Back analysis shows that the role of the Coulomb tail of electron-electron interaction leads asymmetric energy sharing (AES) to be prevalent at recollision. This AES results in the two electrons leaving the ion at different times or with different initial momenta, which is responsible for the anticorrelated behavior in the parallel direction and the intensity-dependent repulsion effect in the transverse direction.
The effect of Coulomb interactions on thermoelectric properties of quantum dots
NASA Astrophysics Data System (ADS)
Zimbovskaya, Natalya; Kuzmin, Valery
2014-03-01
Thermoelectric effects in a quantum dot coupled to the source and drain charge reservoirs are explored using a nonequilibrium Green's functions formalism beyond the Hartree-Fock approxomation. We concentrate on theoretical analysis of the influence of Coulomb interactions on thermopower and the figure of merit ZT . Obtained results show that Coulomb interactions between charge carriers on the dot significantly contribute to its thermoelectric properties. In the present work, we trace the transition from the Coulomb blockade regime to Kondo regime in the thermoelectric properties of the quantum dot which occurs when we gradually strengthen the coupling of the dot to the charge reservoirs. We show that within the Coulomb blockade regime (when the coupling of the dot to the leads is weak compared to the characteristic strength of the charge carriers interactions) thermoelectric characteristics of the dot display distinct features caused by Coulomb interactions. These features indicate possibilities of enhancement of thermoelectric efficiency of the considered systems. Within the Kondo regime, when the couplings of the dot to the leads became stronger, the influence of Coulomb interactions declines bringing a decrease in the the thermoelectric efficiency.
Coulomb-interaction-dependent effect of high-order sideband generation in an optomechanical system
NASA Astrophysics Data System (ADS)
Kong, Cui; Xiong, Hao; Wu, Ying
2017-03-01
High-order sideband generation in an optomechanical system coupled to a charged object is discussed, and the features of Coulomb-interaction-dependent effect are identified. We show that the Coulomb-interaction-dependent effect of high-order sideband generation exhibits essential difference between the case of weak control field and strong control field. In the weak control field case, the output spectra are in the perturbative regime and there is hardly any Coulomb-interaction-dependent effect in an optomechanical system coupling to an object with a small amount of charge. In the strong control field case, the output spectra are in the nonperturbative regime and robust Coulomb-interaction-dependent effect arises even if there are few charges. The amplitudes of specific sidebands are also discussed, and it is shown that Coulomb interaction plays an important role in achieving optomechanical control. Due to the extremely sensitive charge number, the Coulomb-interaction-dependent effect of high-order sideband generation is remarkable in many aspects and may be used to precision measurement of electrical charges beyond the linearized optomechanical interaction.
Fincham, J R
1989-01-01
Transformation with exogenous deoxyribonucleic acid (DNA) now appears to be possible with all fungal species, or at least all that can be grown in culture. This field of research is at present dominated by Saccharomyces cerevisiae and two filamentous members of the class Ascomycetes, Aspergillus nidulans and Neurospora crassa, with substantial contributions also from fission yeast (Schizosaccharomyces pombe) and another filamentous member of the class Ascomycetes, Podospora anserina. However, transformation has been demonstrated, and will no doubt be extensively used, in representatives of most of the main fungal classes, including Phycomycetes, Basidiomycetes (the order Agaricales and Ustilago species), and a number of the Fungi Imperfecti. The list includes a number of plant pathogens, and transformation is likely to become important in the analysis of the molecular basis of pathogenicity. Transformation may be maintained either by using an autonomously replicating plasmid as a vehicle for the transforming DNA or through integration of the DNA into the chromosomes. In S. cerevisiae and other yeasts, a variety of autonomously replicating plasmids have been used successfully, some of them designed for use as shuttle vectors for Escherichia coli as well as for yeast transformation. Suitable plasmids are not yet available for use in filamentous fungi, in which stable transformation is dependent on chromosomal integration. In Saccharomyces cerevisiae, integration of transforming DNA is virtually always by homology; in filamentous fungi, in contrast, it occurs just as frequently at nonhomologous (ectopic) chromosomal sites. The main importance of transformation in fungi at present is in connection with gene cloning and the analysis of gene function. The most advanced work is being done with S. cerevisiae, in which the virtual restriction of stable DNA integration to homologous chromosome loci enables gene disruption and gene replacement to be carried out with greater
Oh, S H; Chater, K F
1997-01-01
Using Streptomyces coelicolor A3(2) protoplasts, the number of transformants obtained by homologous recombination of incoming double-stranded circular DNA with the recipient chromosome was greatly stimulated by simple denaturation of the donor DNA. This procedure was very effective with inserts over a ca. 100-fold size range, the largest tested being ca. 40-kb inserts in cosmids. These observations led to transformation experiments with linearized cloned DNA and randomly sheared genomic DNA. In both cases, DNA denaturation led to significant levels of transformation. Most of the transformants had resulted from the predicted homologous recombination events. A number of genetic manipulations will be made easier or possible by these procedures. PMID:8981988
NASA Astrophysics Data System (ADS)
Strader, A. E.; Jackson, D. D.
2011-12-01
Deng & Sykes (1997) found a strong correlation between receiver earthquake location and positive increase in Coulomb stress (ΔCFF). Assuming a coefficient of friction of 0.6, and resolving stresses onto assumed fault planes with uniform orientation parallel to average Pacific-North American plate motion, they found that only 15% of receiver earthquakes occur in "stress shadows" where the Coulomb stress change should impede faulting. We extended their study by adding two source earthquakes (Hector Mine, 1999 and El Mayor-Cucupah, 2010), and calculating the stress changes at the locations of 134 receiver earthquakes with magnitude 4.4 and greater after 1999. We examined shear stress, normal stress, and Coulomb stress, resolving stresses onto four different hypothetical fault planes: smoothed seismicity-based planes, a weighted average of nearby fault-plane orientations, and the two nodal planes of weighed average moment tensors of nearby earthquakes. We also computed shear, normal, and Coulomb stress histories oriented according to the four choices of fault orientation, and tested the effect of total stress change on receiver earthquake magnitude. Our chi square test results indicate that, with 95% confidence, receiver earthquakes do not tend to avoid stress shadows, and that the choice of plane onto which stress is resolved does not affect the result. On average, 39% of earthquakes occur at the time of maximum stress at the event location, with no significant variation depending on the choice of rupture plane or type of stress change. We found no correlation between earthquake magnitude and total stress change at the events' locations. These results suggest that instantaneous cumulative Coulomb stress, as we and Deng & Sykes modeled it, does not strongly control the locations of future earthquakes. The lack of correlation between Coulomb stress change and magnitude suggests that modeled Coulomb stress change does not control the size of earthquakes once they
Direct evidence for a Coulombic phase in monopole-suppressed SU(2) lattice gauge theory
NASA Astrophysics Data System (ADS)
Grady, Michael
2013-11-01
Further evidence is presented for the existence of a non-confining phase at weak coupling in SU(2) lattice gauge theory. Using Monte Carlo simulations with the standard Wilson action, gauge-invariant SO(3)-Z2 monopoles, which are strong-coupling lattice artifacts, have been seen to undergo a percolation transition exactly at the phase transition previously seen using Coulomb gauge methods, with an infinite lattice critical point near β=3.2. The theory with both Z2 vortices and monopoles and SO(3)-Z2 monopoles eliminated is simulated in the strong-coupling (β=0) limit on lattices up to 604. Here, as in the high-β phase of the Wilson-action theory, finite size scaling shows it spontaneously breaks the remnant symmetry left over after Coulomb gauge fixing. Such a symmetry breaking precludes the potential from having a linear term. The monopole restriction appears to prevent the transition to a confining phase at any β. Direct measurement of the instantaneous Coulomb potential shows a Coulombic form with moderately running coupling possibly approaching an infrared fixed point of α˜1.4. The Coulomb potential is measured to 50 lattice spacings and 2 fm. A short-distance fit to the 2-loop perturbative potential is used to set the scale. High precision at such long distances is made possible through the use of open boundary conditions, which was previously found to cut random and systematic errors of the Coulomb gauge fixing procedure dramatically. The Coulomb potential agrees with the gauge-invariant interquark potential measured with smeared Wilson loops on periodic lattices as far as the latter can be practically measured with similar statistics data.
Comparison of COULOMB-2, NASCAP-2k and SPIS codes for geostationary spacecrafts charging
NASA Astrophysics Data System (ADS)
Novikov, Lev; Makletsov, Andrei; Sinolits, Vadim
In developing of international standards for spacecraft charging, it is necessary to compare results of spacecraft charging modeling obtained with various models. In the paper, electrical potentials for spacecraft 3D models were calculated with COULOMB-2, NASCAP-2k [1] and SPIS [2] software, and the comparison of obtained values was performed. To compare COULOMB-2 and NASCAP-2k codes we used a 3D geometrical model of a spacecraft given in [1]. Parameters of spacecraft surface materials were taken from [1], too. For COULOMB-2 and SPIS cross validation, we carried out calculations with SPIS code through SPENVIS web-interface and with COULOMB-2 software for a spacecraft geometrical model given in SPIS test examples [2]. In both cases, we calculated distributions of electric potentials on the spacecraft surface and visualized the obtained distributions with color code. Pictures of the surface potentials distribution calculated with COULOMB-2 and SPIS software are in good qualitative agreement. Absolute values of surface potentials calculated with these codes for different plasma conditions, are close enough. Pictures of the surface potentials distribution calculated for the spacecraft model [1] with COULOMB-2 software completely correspond to actual understanding of physical mechanisms of differential spacecraft surface charging. In this case, we compared only calculated values of the surface potential for the same space plasma conditions because the potential distributions on the spacecraft surface are absent in [1]. For all the plasma conditions considered, COULOMB-2 model gives higher absolute values of negative potential, than NASCAP-2k model. Differences in these values reach 2-3 kV. The possible explanations of the divergences indicated above are distinctions in calculation procedures of primary plasma currents and secondary emission currents. References 1. Ferguson D.С., Wimberly S.C. 51st AIAA Aerospace Science Meeting 2013 (AIAA 2013-0810). 2. http://dev.spis.org/projects/spine/home/spis
Structural transitions in laterally compressed two-dimensional Coulomb clusters
Rancova, O.; Anisimovas, E.; Varanavicius, T.
2011-03-15
We model structural transitions of small-size Wigner crystals in laterally compressed two-dimensional traps. Ground and metastable configurations are calculated and their transformations are linked to conspicuous changes in the heat capacity of the system. We show that various types of structural transitions are reflected by characteristic features in the behavior of the heat capacity. For deeper understanding, results produced by the Monte Carlo numerical calculations are compared to predictions of simple one-dimensional models.
NASA Astrophysics Data System (ADS)
Anoukou, K.; Pastor, F.; Dufrenoy, P.; Kondo, D.
2016-06-01
The present two-part study aims at investigating the specific effects of Mohr-Coulomb matrix on the strength of ductile porous materials by using a kinematic limit analysis approach. While in the Part II, static and kinematic bounds are numerically derived and used for validation purpose, the present Part I focuses on the theoretical formulation of a macroscopic strength criterion for porous Mohr-Coulomb materials. To this end, we consider a hollow sphere model with a rigid perfectly plastic Mohr-Coulomb matrix, subjected to axisymmetric uniform strain rate boundary conditions. Taking advantage of an appropriate family of three-parameter trial velocity fields accounting for the specific plastic deformation mechanisms of the Mohr-Coulomb matrix, we then provide a solution of the constrained minimization problem required for the determination of the macroscopic dissipation function. The macroscopic strength criterion is then obtained by means of the Lagrangian method combined with Karush-Kuhn-Tucker conditions. After a careful analysis and discussion of the plastic admissibility condition associated to the Mohr-Coulomb criterion, the above procedure leads to a parametric closed-form expression of the macroscopic strength criterion. The latter explicitly shows a dependence on the three stress invariants. In the special case of a friction angle equal to zero, the established criterion reduced to recently available results for porous Tresca materials. Finally, both effects of matrix friction angle and porosity are briefly illustrated and, for completeness, the macroscopic plastic flow rule and the voids evolution law are fully furnished.
Positive and Negative Coulomb Drag in a 1D Quantum Circuit
NASA Astrophysics Data System (ADS)
Laroche, Dominique; Gervais, Guillaume; Lilly, Mike; Reno, John
2012-02-01
We report Coulomb drag measurements between tunable vertically-coupled quantum wires. The wires are fabricated in a GaAs/AlGaAs double quantum well heterostructure with a 15 nm barrier separating the quantum wells. The Coulomb drag signal is mapped out versus the number of subbands occupied in each wire, and regions of both positive and negative drag are observed (D. Laroche et. al. Nature Nanotechnology, doi:10.1038/nnano.2011.182). The observation of negative Coulomb drag at a high one-dimensional electronic density is not predicted by the usual momentum-transfer model for Coulomb drag and shows that the existing picture of the drag effect in one-dimension is incomplete. In order to clarify the origin of this negative signal, temperature dependencies of the Coulomb drag are presented both in the positive and in the negative drag regimes. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Observations of Coulomb explosion in doubly charged atomic and molecular clusters
NASA Astrophysics Data System (ADS)
Gotts, N. G.; Lethbridge, P. G.; Stace, A. J.
1992-01-01
Coulomb explosion has been promoted in a range of doubly charged atomic and molecular clusters. In these new experiments, mass selected clusters of Ar2+n, (CO2)2+n, (H2O)2+n, (H2O)nH2+2, (CH3CN)nH2+2, and (C6H6)2+n have been subjected to collisional activation with a background gas. For species close to the Coulomb cutoff, each collision removes sufficient atoms or molecules (approximately six) as to render the clusters unstable. As a result, charge separation occurs and part (≂30%) of the Coulomb repulsion energy is released in the form of center of mass kinetic energy in the fragments. The remaining Coulomb energy appears as internal excitation in the fragments and subsequently leads to extensive evaporation. It is shown that the latter process is continuing even 10-6 s after Coulomb explosion. All the molecular systems studied show evidence of asymmetric charge separation, with some singly charged fragments containing up to 65% of the initial cluster mass. A detailed quantitative analysis of the results is made difficult by the very broad range of fragment ion sizes.
Three-Body Coulomb Functions in the Hyperspherical Adiabatic Expansion Method
NASA Astrophysics Data System (ADS)
Garrido, E.; Kievsky, A.; Viviani, M.
2016-12-01
In this work we describe a numerical method devised to compute continuum three-body wave functions. The method is implemented using the hyperspherical adiabatic expansion for the three-body wave function imposing a box boundary condition. The continuum energy spectrum results discretized and, for specific quantum number values, all the possible incoming and outgoing channels are simultaneously computed. For a given energy, the hyperradial continuum functions form a matrix whose ij-term refers to specific incoming and outgoing channels. When applied to three-body systems interacting only through the Coulomb potential, this method provides the adiabatic representation of the regular three-body Coulomb wave function. The computation of the irregular Coulomb wave function representation is also discussed. These regular and irregular Coulomb functions can be used to extract the S-matrix for those reactions where, together with some short-range potential, the Coulomb interaction is also present. The method is illustrated in the case of the 3→ 3 process of three alpha particles.
ERIC Educational Resources Information Center
Karp, Melinda Mechur; Kalamkarian, Hoori Santikian; Klempin, Serena; Fletcher, Jeffrey
2016-01-01
This paper examines technology-mediated advising reform in order to contribute to the understanding of how colleges engage in transformative change to improve student outcomes. Conceptualizing such change as occurring along three interrelated dimensions of organizational functioning (structural, process, and attitudinal), we seek to understand the…
ERIC Educational Resources Information Center
Denning, Peter J.; Hiles, John E.
2006-01-01
Transformational Events is a new pedagogic pattern that explains how innovations (and other transformations) happened. The pattern is three temporal stages: an interval of increasingly unsatisfactory ad hoc solutions to a persistent problem (the "mess"), an offer of an invention or of a new way of thinking, and a period of widespread adoption and…
ERIC Educational Resources Information Center
Reeves, Melinda
2006-01-01
The parents of students who attend Decatur High School thought that there was little hope of their kids going on to college. After a year or so in Decatur's reading program, their sons and daughters were both transformed and college bound. In this article, the author describes how Decatur was able to successfully transform their students. Seven…
NASA Astrophysics Data System (ADS)
Zhang, G. L.; Pan, M.
2016-10-01
The Coulomb barrier heights are calculated by using the proximity potential with a new universal function in comparison with the results of proximity potentials Prox77, AW95, Bass73, BW91, CW76, DP and Ng80. It is found that the new results of Coulomb barrier heights are better than those of most proximity potentials. Then this proximity potential with the new universal function was used to calculate the Coulomb barrier positions and heights from light fusion systems to heavy fusion systems. The parametrized formulas are obtained for Coulomb barrier height and position, and can reproduce most of calculated barrier heights and positions within the accuracy of ± 1%.
Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics
Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing
2016-01-01
In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends. PMID:27256904
NASA Astrophysics Data System (ADS)
Yudin, G. L.; Patchkovskii, S.; Corkum, P. B.; Bandrauk, A. D.
2007-03-01
We develop a description of laser-assisted x-ray photoionization based on a sudden approximation approach. By splitting the system evolution into three time stages we find necessary and sufficient conditions for spatial and temporal separation of Coulomb and Volkov continuum solutions. Using the separable Coulomb-Volkov wavefunction we present an analytical non-relativistic quantum theory of attosecond photoionization. It applies for arbitrary x-ray parameters, with both Coulomb continuum and laser field treated non-perturbatively. The theory provides a firm basis for characterizing photoelectron phase and atomic and molecular wavefunctions, by extracting them from experimental data. Using the molecular hydrogen ion as a test case, we display a variety of photoelectron interference sources in energy- and angular-resolved spectra for different pulse durations, chirps and delay times between x-ray pulse replicas.