Accurate determinations of alpha(s) from realistic lattice QCD.

PubMed

Mason, Q; Trottier, H D; Davies, C T H; Foley, K; Gray, A; Lepage, G P; Nobes, M; Shigemitsu, J

2005-07-29

We obtain a new value for the QCD coupling constant by combining lattice QCD simulations with experimental data for hadron masses. Our lattice analysis is the first to (1) include vacuum polarization effects from all three light-quark flavors (using MILC configurations), (2) include third-order terms in perturbation theory, (3) systematically estimate fourth and higher-order terms, (4) use an unambiguous lattice spacing, and (5) use an [symbol: see text](a2)-accurate QCD action. We use 28 different (but related) short-distance quantities to obtain alpha((5)/(MS))(M(Z)) = 0.1170(12).

The actual scaling of a nominally third-order Reynolds stress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krommes, J. A., E-mail: krommes@princeton.edu; Hammett, G. W., E-mail: hammett@princeton.edu

2014-05-15

It is shown that a particular higher-order Reynolds stress arising from a term in the third-order gyrokinetic Hamiltonian is smaller than it nominally appears to be. However, it does not follow that all third-order terms are unimportant. The discussion is relevant to the ongoing debate about the importance of higher-order terms in the gyrokinetic theory of momentum transport.

Double ionization of helium by ion impact: second Born order treatment at the fully differential level

NASA Astrophysics Data System (ADS)

López, S. D.; Otranto, S.; Garibotti, C. R.

2015-01-01

In this work, a theoretical study of the double ionization of He by ion impact at the fully differential level is presented. Emphasis is made in the role played by the projectile in the double emission process depending on its charge and the amount of momentum transferred to the target. A Born-CDW model including a second-order term in the projectile charge is introduced and evaluated within an on-shell treatment. We find that emission geometries for which the second-order term dominates lead to asymmetric structures around the momentum transfer direction, a typical characteristic of higher order transitions.

Autism, Context/Noncontext Information Processing, and Atypical Development

PubMed Central

Skoyles, John R.

2011-01-01

Autism has been attributed to a deficit in contextual information processing. Attempts to understand autism in terms of such a defect, however, do not include more recent computational work upon context. This work has identified that context information processing depends upon the extraction and use of the information hidden in higher-order (or indirect) associations. Higher-order associations underlie the cognition of context rather than that of situations. This paper starts by examining the differences between higher-order and first-order (or direct) associations. Higher-order associations link entities not directly (as with first-order ones) but indirectly through all the connections they have via other entities. Extracting this information requires the processing of past episodes as a totality. As a result, this extraction depends upon specialised extraction processes separate from cognition. This information is then consolidated. Due to this difference, the extraction/consolidation of higher-order information can be impaired whilst cognition remains intact. Although not directly impaired, cognition will be indirectly impaired by knock on effects such as cognition compensating for absent higher-order information with information extracted from first-order associations. This paper discusses the implications of this for the inflexible, literal/immediate, and inappropriate information processing of autistic individuals. PMID:22937255

A higher-order Skyrme model

NASA Astrophysics Data System (ADS)

Gudnason, Sven Bjarke; Nitta, Muneto

2017-09-01

We propose a higher-order Skyrme model with derivative terms of eighth, tenth and twelfth order. Our construction yields simple and easy-to-interpret higher-order Lagrangians. We first show that a Skyrmion with higher-order terms proposed by Marleau has an instability in the form of a baby-Skyrmion string, while the static energies of our construction are positive definite, implying stability against time-independent perturbations. However, we also find that the Hamiltonians of our construction possess two kinds of dynamical instabilities, which may indicate the instability with respect to time-dependent perturbations. Different from the well-known Ostrogradsky instability, the instabilities that we find are intrinsically of nonlinear nature and also due to the fact that even powers of the inverse metric gives a ghost-like higher-order kinetic-like term. The vacuum state is, however, stable. Finally, we show that at sufficiently low energies, our Hamiltonians in the simplest cases, are stable against time-dependent perturbations.

Extended nonlinear Schrödinger equation with higher-order odd and even terms and its rogue wave solutions.

PubMed

Ankiewicz, Adrian; Wang, Yan; Wabnitz, Stefan; Akhmediev, Nail

2014-01-01

We consider an extended nonlinear Schrödinger equation with higher-order odd (third order) and even (fourth order) terms with variable coefficients. The resulting equation has soliton solutions and approximate rogue wave solutions. We present these solutions up to second order. Moreover, specific constraints on the parameters of higher-order terms provide integrability of the resulting equation, providing a corresponding Lax pair. Particular cases of this equation are the Hirota and the Lakshmanan-Porsezian-Daniel equations. The resulting integrable equation admits exact rogue wave solutions. In particular cases, mentioned above, these solutions are reduced to the rogue wave solutions of the corresponding equations.

Multi-instantons and exact results III: Unification of even and odd anharmonic oscillators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jentschura, Ulrich D.; Surzhykov, Andrey; GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt

2010-05-15

This is the third article in a series of three papers on the resonance energy levels of anharmonic oscillators. Whereas the first two papers mainly dealt with double-well potentials and modifications thereof [see J. Zinn-Justin, U.D. Jentschura, Ann. Phys. (N.Y.) 313 (2004) 197 and 269], we here focus on simple even and odd anharmonic oscillators for arbitrary magnitude and complex phase of the coupling parameter. A unification is achieved by the use of PT-symmetry inspired dispersion relations and generalized quantization conditions that include instanton configurations. Higher-order formulas are provided for the oscillators of degrees 3 to 8, which lead tomore » subleading corrections to the leading factorial growth of the perturbative coefficients describing the resonance energies. Numerical results are provided, and higher-order terms are found to be numerically significant. The resonances are described by generalized expansions involving intertwined nonanalytic exponentials, logarithmic terms and power series. Finally, we summarize spectral properties and dispersion relations of anharmonic oscillators, and their interconnections. The purpose is to look at one of the classic problems of quantum theory from a new perspective, through which we gain systematic access to the phenomenologically significant higher-order terms.« less

Approximate optimal guidance for the advanced launch system

NASA Technical Reports Server (NTRS)

Feeley, T. S.; Speyer, J. L.

1993-01-01

A real-time guidance scheme for the problem of maximizing the payload into orbit subject to the equations of motion for a rocket over a spherical, non-rotating earth is presented. An approximate optimal launch guidance law is developed based upon an asymptotic expansion of the Hamilton - Jacobi - Bellman or dynamic programming equation. The expansion is performed in terms of a small parameter, which is used to separate the dynamics of the problem into primary and perturbation dynamics. For the zeroth-order problem the small parameter is set to zero and a closed-form solution to the zeroth-order expansion term of Hamilton - Jacobi - Bellman equation is obtained. Higher-order terms of the expansion include the effects of the neglected perturbation dynamics. These higher-order terms are determined from the solution of first-order linear partial differential equations requiring only the evaluation of quadratures. This technique is preferred as a real-time, on-line guidance scheme to alternative numerical iterative optimization schemes because of the unreliable convergence properties of these iterative guidance schemes and because the quadratures needed for the approximate optimal guidance law can be performed rapidly and by parallel processing. Even if the approximate solution is not nearly optimal, when using this technique the zeroth-order solution always provides a path which satisfies the terminal constraints. Results for two-degree-of-freedom simulations are presented for the simplified problem of flight in the equatorial plane and compared to the guidance scheme generated by the shooting method which is an iterative second-order technique.

Intermediary LEO propagation including higher order zonal harmonics

NASA Astrophysics Data System (ADS)

Hautesserres, Denis; Lara, Martin

2017-04-01

Two new intermediary orbits of the artificial satellite problem are proposed. The analytical solutions include higher order effects of the geopotential, and are obtained by means of a torsion transformation applied to the quasi-Keplerian system resulting after the elimination of the parallax simplification, for the first intermediary, and after the elimination of the parallax and perigee simplifications, for the second one. The new intermediaries perform notably well for low Earth orbits propagation, are free from special functions, and result advantageous, both in accuracy and efficiency, when compared to the standard Cowell integration of the J_2 problem, thus providing appealing alternatives for onboard, short-term, orbit propagation under limited computational resources.

Ambiguities in the definition of quasilocal mass

NASA Technical Reports Server (NTRS)

Woodhouse, N. M. J.

1987-01-01

For a small surface in a vacuum spacetime, some components of the kinematic twistor are nonzero at the fifth order in the diameter of the surface even though, according to Penrose's (1986) modified construction, the leading term in the quasi-local mass m(p) is sixth order (or higher). This implies that the leading term in m(p) cannot be defined independently of higher-order terms in the twistor norm.

Integrated and differential accuracy in resummed cross sections

DOE PAGES

Bertolini, Daniele; Solon, Mikhail P.; Walsh, Jonathan R.

2017-03-30

Standard QCD resummation techniques provide precise predictions for the spectrum and the cumulant of a given observable. The integrated spectrum and the cumulant differ by higher-order terms which, however, can be numerically significant. Here in this paper we propose a method, which we call the σ-improved scheme, to resolve this issue. It consists of two steps: (i) include higher-order terms in the spectrum to improve the agreement with the cumulant central value, and (ii) employ profile scales that encode correlations between different points to give robust uncertainty estimates for the integrated spectrum. We provide a generic algorithm for determining suchmore » profile scales, and show the application to the thrust distribution in e +e - collisions at NLL'+NLO and NNLL'+NNLO.« less

Stability analysis solutions and optical solitons in extended nonlinear Schrödinger equation with higher-order odd and even terms

NASA Astrophysics Data System (ADS)

Peng, Wei-Qi; Tian, Shou-Fu; Zou, Li; Zhang, Tian-Tian

2018-01-01

In this paper, the extended nonlinear Schrödinger equation with higher-order odd (third order) and even (fourth order) terms is investigated, whose particular cases are the Hirota equation, the Sasa-Satsuma equation and Lakshmanan-Porsezian-Daniel equation by selecting some specific values on the parameters of higher-order terms. We first study the stability analysis of the equation. Then, using the ansatz method, we derive its bright, dark solitons and some constraint conditions which can guarantee the existence of solitons. Moreover, the Ricatti equation extension method is employed to derive some exact singular solutions. The outstanding characteristics of these solitons are analyzed via several diverting graphics.

3D Higher Order Modeling in the BEM/FEM Hybrid Formulation

NASA Technical Reports Server (NTRS)

Fink, P. W.; Wilton, D. R.

2000-01-01

Higher order divergence- and curl-conforming bases have been shown to provide significant benefits, in both convergence rate and accuracy, in the 2D hybrid finite element/boundary element formulation (P. Fink and D. Wilton, National Radio Science Meeting, Boulder, CO, Jan. 2000). A critical issue in achieving the potential for accuracy of the approach is the accurate evaluation of all matrix elements. These involve products of high order polynomials and, in some instances, singular Green's functions. In the 2D formulation, the use of a generalized Gaussian quadrature method was found to greatly facilitate the computation and to improve the accuracy of the boundary integral equation self-terms. In this paper, a 3D, hybrid electric field formulation employing higher order bases and higher order elements is presented. The improvements in convergence rate and accuracy, compared to those resulting from lower order modeling, are established. Techniques developed to facilitate the computation of the boundary integral self-terms are also shown to improve the accuracy of these terms. Finally, simple preconditioning techniques are used in conjunction with iterative solution procedures to solve the resulting linear system efficiently. In order to handle the boundary integral singularities in the 3D formulation, the parent element- either a triangle or rectangle-is subdivided into a set of sub-triangles with a common vertex at the singularity. The contribution to the integral from each of the sub-triangles is computed using the Duffy transformation to remove the singularity. This method is shown to greatly facilitate t'pe self-term computation when the bases are of higher order. In addition, the sub-triangles can be further divided to achieve near arbitrary accuracy in the self-term computation. An efficient method for subdividing the parent element is presented. The accuracy obtained using higher order bases is compared to that obtained using lower order bases when the number of unknowns is approximately equal. Also, convergence rates obtained using higher order bases are compared to those obtained with lower order bases for selected sample

Neural Classifiers for Learning Higher-Order Correlations

NASA Astrophysics Data System (ADS)

Güler, Marifi

1999-01-01

Studies by various authors suggest that higher-order networks can be more powerful and are biologically more plausible with respect to the more traditional multilayer networks. These architectures make explicit use of nonlinear interactions between input variables in the form of higher-order units or product units. If it is known a priori that the problem to be implemented possesses a given set of invariances like in the translation, rotation, and scale invariant pattern recognition problems, those invariances can be encoded, thus eliminating all higher-order terms which are incompatible with the invariances. In general, however, it is a serious set-back that the complexity of learning increases exponentially with the size of inputs. This paper reviews higher-order networks and introduces an implicit representation in which learning complexity is mainly decided by the number of higher-order terms to be learned and increases only linearly with the input size.

Precision comparison of the power spectrum in the EFTofLSS with simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foreman, Simon; Senatore, Leonardo; Perrier, Hideki, E-mail: sfore@stanford.edu, E-mail: senatore@stanford.edu, E-mail: hideki.perrier@unige.ch

2016-05-01

We study the prediction of the dark matter power spectrum at two-loop order in the Effective Field Theory of Large Scale Structures (EFTofLSS) using high precision numerical simulations. In our universe, short distance non-linear fluctuations, not under perturbative control, affect long distance fluctuations through an effective stress tensor that needs to be parametrized in terms of counterterms that are functions of the long distance fluctuating fields. We find that at two-loop order it is necessary to include three counterterms: a linear term in the overdensity, δ, a quadratic term, δ{sup 2}, and a higher derivative term, ∂{sup 2}δ. After themore » inclusion of these three terms, the EFTofLSS at two-loop order matches simulation data up to k ≅ 0.34 h Mpc{sup −1} at redshift z = 0, up to k ≅ 0.55 h Mpc{sup −1} at z = 1, and up to k ≅ 1.1 h Mpc{sup −1} at z = 2. At these wavenumbers, the cosmic variance of the simulation is at least as small as 10{sup −3}, providing for the first time a high precision comparison between theory and data. The actual reach of the theory is affected by theoretical uncertainties associated to not having included higher order terms in perturbation theory, for which we provide an estimate, and by potentially overfitting the data, which we also try to address. Since in the EFTofLSS the coupling constants associated with the counterterms are unknown functions of time, we show how a simple parametrization gives a sensible description of their time-dependence. Overall, the k -reach of the EFTofLSS is much larger than previous analytical techniques, showing that the amount of cosmological information amenable to high-precision analytical control might be much larger than previously believed.« less

The influence of the great inequality on the secular disturbing function of the planetary system.

NASA Technical Reports Server (NTRS)

Musen, P.

1971-01-01

This paper derives the contribution by the great inequality to the secular disturbing function of the principal planets. Andoyer's expansion of the planetary disturbing function and von Zeipel's method of eliminating the periodic terms is employed; thereby, the corrected secular disturbing function for the planetary system is derived. The conclusion is drawn that the canonicity of the equations for the secular variation of the heliocentric elements can be preserved if there be retained, in the secular disturbing function, terms only of the second and fourth order relative to the eccentricity and inclinations. The Krylov-Bogoliubov method is suggested for eliminating periodic terms, if it is desired to include the secular perturbations of the fifth and higher order in the heliocentric elements. The additional part of the secular disturbing function derived in this paper can be included in existing theories of the secular effects of principal planets.

Renormalization scheme dependence of high-order perturbative QCD predictions

NASA Astrophysics Data System (ADS)

Ma, Yang; Wu, Xing-Gang

2018-02-01

Conventionally, one adopts typical momentum flow of a physical observable as the renormalization scale for its perturbative QCD (pQCD) approximant. This simple treatment leads to renormalization scheme-and-scale ambiguities due to the renormalization scheme and scale dependence of the strong coupling and the perturbative coefficients do not exactly cancel at any fixed order. It is believed that those ambiguities will be softened by including more higher-order terms. In the paper, to show how the renormalization scheme dependence changes when more loop terms have been included, we discuss the sensitivity of pQCD prediction on the scheme parameters by using the scheme-dependent {βm ≥2}-terms. We adopt two four-loop examples, e+e-→hadrons and τ decays into hadrons, for detailed analysis. Our results show that under the conventional scale setting, by including more-and-more loop terms, the scheme dependence of the pQCD prediction cannot be reduced as efficiently as that of the scale dependence. Thus a proper scale-setting approach should be important to reduce the scheme dependence. We observe that the principle of minimum sensitivity could be such a scale-setting approach, which provides a practical way to achieve optimal scheme and scale by requiring the pQCD approximate be independent to the "unphysical" theoretical conventions.

Higher-order rational solitons and rogue-like wave solutions of the (2 + 1)-dimensional nonlinear fluid mechanics equations

NASA Astrophysics Data System (ADS)

Wen, Xiao-Yong; Yan, Zhenya

2017-02-01

The novel generalized perturbation (n, M)-fold Darboux transformations (DTs) are reported for the (2 + 1)-dimensional Kadomtsev-Petviashvili (KP) equation and its extension by using the Taylor expansion of the Darboux matrix. The generalized perturbation (1 , N - 1) -fold DTs are used to find their higher-order rational solitons and rogue wave solutions in terms of determinants. The dynamics behaviors of these rogue waves are discussed in detail for different parameters and time, which display the interesting RW and soliton structures including the triangle, pentagon, heptagon profiles, etc. Moreover, we find that a new phenomenon that the parameter (a) can control the wave structures of the KP equation from the higher-order rogue waves (a ≠ 0) into higher-order rational solitons (a = 0) in (x, t)-space with y = const . These results may predict the corresponding dynamical phenomena in the models of fluid mechanics and other physically relevant systems.

Design of blade-shaped-electrode linear ion traps with reduced anharmonic contributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, K.; Che, H.; Ge, Y. P.

2015-09-21

RF quadrupole linear Paul traps are versatile tools in quantum physics experiments. Linear Paul traps with blade-shaped electrodes have the advantages of larger solid angles for fluorescence collection. But with these kinds of traps, the existence of higher-order anharmonic terms of the trap potentials can cause large heating rate for the trapped ions. In this paper, we theoretically investigate the dependence of higher-order terms of trap potentials on the geometry of blade-shaped traps, and offer an optimized design. A modified blade electrodes trap is proposed to further reduce higher-order anharmonic terms while still retaining large fluorescence collection angle.

The use of touch to enhance nursing care of older person in long-term mental health care facilities.

PubMed

Gleeson, M; Timmins, F

2004-10-01

The self-care deficits experienced by older clients in long-term mental health settings, because of cognitive impairment, are likely to impact upon the clients' higher-order needs. The practice of nursing the elderly involves a lot of personal contact, during the delivery of fundamental physical care. While physiological and safety needs are crucial to clients in long-term settings, higher-order needs need also to be addressed. From the clients' perspective nurse's use of touch provides comfort, warmth and security, although there is a dearth of empirical evidence of these benefits. This paper explores the nurse's use of touch, the impact of touch and the experiences of touch on the older person in long-term settings. Because of the dearth of research in the use of touch with elderly clients in long-term care mental health facilities, a review of the literature was performed on the topic. This revealed that touch by nurses is frequently associated with routine tasks within nursing, and is less likely to be a caring touch intervention. Recommendations include further research on the topic and caution with widespread adoption of caring touch as an intervention.

A critical evaluation of perturbation theories by Monte Carlo simulation of the first four perturbation terms in a Helmholtz energy expansion for the Lennard-Jones fluid

NASA Astrophysics Data System (ADS)

van Westen, Thijs; Gross, Joachim

2017-07-01

The Helmholtz energy of a fluid interacting by a Lennard-Jones pair potential is expanded in a perturbation series. Both the methods of Barker-Henderson (BH) and of Weeks-Chandler-Andersen (WCA) are evaluated for the division of the intermolecular potential into reference and perturbation parts. The first four perturbation terms are evaluated for various densities and temperatures (in the ranges ρ*=0 -1.5 and T*=0.5 -12 ) using Monte Carlo simulations in the canonical ensemble. The simulation results are used to test several approximate theoretical methods for describing perturbation terms or for developing an approximate infinite order perturbation series. Additionally, the simulations serve as a basis for developing fully analytical third order BH and WCA perturbation theories. The development of analytical theories allows (1) a careful comparison between the BH and WCA formalisms, and (2) a systematic examination of the effect of higher-order perturbation terms on calculated thermodynamic properties of fluids. Properties included in the comparison are supercritical thermodynamic properties (pressure, internal energy, and chemical potential), vapor-liquid phase equilibria, second virial coefficients, and heat capacities. For all properties studied, we find a systematically improved description upon using a higher-order perturbation theory. A result of particular relevance is that a third order perturbation theory is capable of providing a quantitative description of second virial coefficients to temperatures as low as the triple-point of the Lennard-Jones fluid. We find no reason to prefer the WCA formalism over the BH formalism.

Higher-order Skyrme hair of black holes

NASA Astrophysics Data System (ADS)

Gudnason, Sven Bjarke; Nitta, Muneto

2018-05-01

Higher-order derivative terms are considered as replacement for the Skyrme term in an Einstein-Skyrme-like model in order to pinpoint which properties are necessary for a black hole to possess stable static scalar hair. We find two new models able to support stable black hole hair in the limit of the Skyrme term being turned off. They contain 8 and 12 derivatives, respectively, and are roughly the Skyrme-term squared and the so-called BPS-Skyrme-term squared. In the twelfth-order model we find that the lower branches, which are normally unstable, become stable in the limit where the Skyrme term is turned off. We check this claim with a linear stability analysis. Finally, we find for a certain range of the gravitational coupling and horizon radius, that the twelfth-order model contains 4 solutions as opposed to 2. More surprisingly, the lowest part of the would-be unstable branch turns out to be the stable one of the 4 solutions.

On the surface-to-bulk mode conversion of Rayleigh waves.

NASA Technical Reports Server (NTRS)

Chang, C.-P.; Tuan, H.-S.

1973-01-01

Surface-to-bulk wave conversion phenomena occurring at a discontinuity characterized by a surface contour deformation are shown to be usable as a means for tapping Rayleigh waves in a nonpiezoelectric solid. A boundary perturbation technique is used in the treatment of the mode conversion problem. A systematic procedure is presented for calculating not only the first-order scattered waves, which include the reflected surface wave and the converted bulk wave, but also the higher order terms.

Multiple scattering effects with cyclical terms in active remote sensing of vegetated surface using vector radiative transfer theory

USDA-ARS?s Scientific Manuscript database

The energy transport in a vegetated (corn) surface layer is examined by solving the vector radiative transfer equation using a numerical iterative approach. This approach allows a higher order that includes the multiple scattering effects. Multiple scattering effects are important when the optical t...

The Impact of Threat of Shock-Induced Anxiety on Memory Encoding and Retrieval

ERIC Educational Resources Information Center

Bolton, Sorcha; Robinson, Oliver J.

2017-01-01

Anxiety disorders are the most common mental health disorders, and daily transient feelings of anxiety (or "stress") are ubiquitous. However, the precise impact of both transient and pathological anxiety on higher-order cognitive functions, including short- and long-term memory, is poorly understood. A clearer understanding of the…

Modeling the physisorption of graphene on metals

NASA Astrophysics Data System (ADS)

Tao, Jianmin; Tang, Hong; Patra, Abhirup; Bhattarai, Puskar; Perdew, John P.

2018-04-01

Many processes of technological and fundamental importance occur on surfaces. Adsorption is one of these phenomena that has received the most attention. However, it presents a great challenge to conventional density functional theory. Starting with the Lifshitz-Zaremba-Kohn second-order perturbation theory, here we develop a long-range van der Waals (vdW) correction for physisorption of graphene on metals. The model importantly includes quadrupole-surface interaction and screening effects. The results show that, when the vdW correction is combined with the Perdew-Burke-Enzerhof functional, it yields adsorption energies in good agreement with the random-phase approximation, significantly improving upon other vdW methods. We also find that, compared with the leading-order interaction, the higher-order quadrupole-surface correction accounts for about 25 % of the total vdW correction, suggesting the importance of the higher-order term.

Lamb shift and fine structure at n =2 in a hydrogenlike muonic atom with the nuclear spin I =0

NASA Astrophysics Data System (ADS)

Korzinin, Evgeny Yu.; Shelyuto, Valery A.; Ivanov, Vladimir G.; Karshenboim, Savely G.

2018-01-01

The paper is devoted to the Lamb shift and fine structure in a hydrogenlike muonic atom with a spinless nucleus up to the order α5m with all the recoil corrections included. Enhanced contributions of a higher order are also considered. We present the results on the pure QED contribution and on the finite-nuclear-size contribution, proportional to RN2, with the higher-order corrections included. We also consider the consistency of the pure QED theory and the evaluation of the nuclear-structure effects. Most of the QED theory is the same as the theory for the case of the nuclear spin 1/2. Additional nuclear-spin-dependent terms are considered in detail. The issue of the difference for the theories with a spinor nucleus and a scalar one is discussed for the recoil contributions in the order (Zα ) 4m ,α (Zα ) 4m , and (Zα ) 5m . The numerical results are presented for the muonic atoms with two lightest scalar nuclei, helium-4 and beryllium-10. We compare the theory of those muonic atoms with theory for the muonic hydrogen. Some higher-order finite-nuclear-size corrections for the Lamb shift in muonic hydrogen are revisited.

Neoclassical transport including collisional nonlinearity.

PubMed

Candy, J; Belli, E A

2011-06-10

In the standard δf theory of neoclassical transport, the zeroth-order (Maxwellian) solution is obtained analytically via the solution of a nonlinear equation. The first-order correction δf is subsequently computed as the solution of a linear, inhomogeneous equation that includes the linearized Fokker-Planck collision operator. This equation admits analytic solutions only in extreme asymptotic limits (banana, plateau, Pfirsch-Schlüter), and so must be solved numerically for realistic plasma parameters. Recently, numerical codes have appeared which attempt to compute the total distribution f more accurately than in the standard ordering by retaining some nonlinear terms related to finite-orbit width, while simultaneously reusing some form of the linearized collision operator. In this work we show that higher-order corrections to the distribution function may be unphysical if collisional nonlinearities are ignored.

Second- and Higher-Order Virial Coefficients Derived from Equations of State for Real Gases

ERIC Educational Resources Information Center

Parkinson, William A.

2009-01-01

Derivation of the second- and higher-order virial coefficients for models of the gaseous state is demonstrated by employing a direct differential method and subsequent term-by-term comparison to power series expansions. This communication demonstrates the application of this technique to van der Waals representations of virial coefficients.…

Tidal evolution of close binary asteroid systems

NASA Astrophysics Data System (ADS)

Taylor, Patrick A.; Margot, Jean-Luc

2010-12-01

We provide a generalized discussion of tidal evolution to arbitrary order in the expansion of the gravitational potential between two spherical bodies of any mass ratio. To accurately reproduce the tidal evolution of a system at separations less than 5 times the radius of the larger primary component, the tidal potential due to the presence of a smaller secondary component is expanded in terms of Legendre polynomials to arbitrary order rather than truncated at leading order as is typically done in studies of well-separated system like the Earth and Moon. The equations of tidal evolution including tidal torques, the changes in spin rates of the components, and the change in semimajor axis (orbital separation) are then derived for binary asteroid systems with circular and equatorial mutual orbits. Accounting for higher-order terms in the tidal potential serves to speed up the tidal evolution of the system leading to underestimates in the time rates of change of the spin rates, semimajor axis, and mean motion in the mutual orbit if such corrections are ignored. Special attention is given to the effect of close orbits on the calculation of material properties of the components, in terms of the rigidity and tidal dissipation function, based on the tidal evolution of the system. It is found that accurate determinations of the physical parameters of the system, e.g., densities, sizes, and current separation, are typically more important than accounting for higher-order terms in the potential when calculating material properties. In the scope of the long-term tidal evolution of the semimajor axis and the component spin rates, correcting for close orbits is a small effect, but for an instantaneous rate of change in spin rate, semimajor axis, or mean motion, the close-orbit correction can be on the order of tens of percent. This work has possible implications for the determination of the Roche limit and for spin-state alteration during close flybys.

Short-term effects of instillation of a rebamipide suspension on visual function.

PubMed

Kaido, Minako; Ishida, Reiko; Dogru, Murat; Tsubota, Kazuo

2014-05-01

To investigate the short-term adverse effects of using rebamipide for the treatment of dry eye by assessing visual function and optical quality. This interventional noncomparative study included 14 right eyes of 14 healthy volunteers. Serial measurements of visual acuity (VA) and higher-order aberrations were obtained prior to instillation of the rebamipide suspension (baseline) and immediately after and at 5, 10, 20, and 30 min after instillation. Functional VA measurement was performed over a 60-s period with the subject blinking naturally. Ocular aberrations were measured for 10 s while the subject was told not to blink, but no topical anesthesia was applied. Each patient also filled out a questionnaire exploring the rebamipide-associated adverse effects. There was no significant difference between functional VA measured at baseline and at each time point after the instillation of rebamipide. In contrast, the root mean square of third-order and total higher-order aberrations increased significantly immediately after drug instillation (P<0.05). The severity of higher-order aberrations at baseline was similar to that observed at 5, 10, 20, and 30 min after instillation (P>0.05). The transient reduction in optical quality immediately after administration of rebamipide is corrected by the patient's natural blink reflex. The adverse effects observed in this study do not outweigh the benefits of rebamipide treatment.

Dynamical Landscape of Heart Rhythm in Long-Term Heart Transplant Recipients: A Way to Discern Erratic Rhythms

PubMed Central

Wdowczyk, Joanna; Makowiec, Danuta; Gruchała, Marcin; Wejer, Dorota; Struzik, Zbigniew R.

2018-01-01

It is commonly believed that higher values of heart rate variability (HRV) indices account for better organization of the network of feedback reflexes driving an organism's response to actual bodily needs. In order to evaluate this organization in heart transplant (HTX) recipients, 58 nocturnal Holter signals of 14 HTX patients were analyzed. Their dynamical properties were evaluated by short-term HRV indices and measures grounded on entropy. Estimates grouped according to the patients' clinical progress: free of complications versus with complications, and arranged in order of the length of time since the HTX, lead us to the conclusion that higher HRV is associated with a worse outcome for HTX patients. Moreover, short-term HRV indices that are constant, rather than increasing over time, serve well in the prognosis of the future state of a HTX patient. These findings suggest that increases observed in HRV indices are related to erratic rhythms resulting from remodeling of the cardiac tissue (including heterogeneous innervation) in long-term HTX patients. Therefore, we hypothesize that dynamical landscape markers (entropy and fragmentation measures together with the short-term HRV indices) can serve as a tool in the exploration of the genesis of (non-respiratory sinus) arrhythmia. PMID:29686620

Computational Complexity of Bosons in Linear Networks

DTIC Science & Technology

2017-03-01

photon statistics while strongly reducing emission probabilities: thus leading experimental teams pursuing large-scale BOSONSAMPLING have faced a hard...Potentially, this could motivate new validation protocols exploiting statistics that include this temporal degree of freedom. The impact of...photon- statistics polluted by higher-order terms, which can be mistakenly interpreted as decreased photon-indistinguishability. In fact, in many cases

Intact Inner Speech Use in Autism Spectrum Disorder: Evidence from a Short-Term Memory Task

ERIC Educational Resources Information Center

Williams, David; Happe, Francesca; Jarrold, Christopher

2008-01-01

Background: Inner speech has been linked to higher-order cognitive processes including "theory of mind", self-awareness and executive functioning, all of which are impaired in autism spectrum disorder (ASD). Individuals with ASD, themselves, report a propensity for visual rather than verbal modes of thinking. This study explored the extent to…

Keldysh meets Lindblad: Correlated Gain and Loss in Higher Order Perturbation Theory

NASA Astrophysics Data System (ADS)

Stace, Tom; Mueller, Clemens

Motivated by correlated decay processes driving gain, loss and lasing in driven artificial quantum systems, we develop a theoretical technique using Keldysh diagrammatic perturbation theory to derive a Lindblad master equation that goes beyond the usual second order perturbation theory. We demonstrate the method on the driven dissipative Rabi model, including terms up to fourth order in the interaction between the qubit and both the resonator and environment. This results in a large class of Lindblad dissipators and associated rates which go beyond the terms that have previously been proposed to describe similar systems. All of the additional terms contribute to the system behaviour at the same order of perturbation theory. We then apply these results to analyse the phonon-assisted steady-state gain of a microwave field driving a double quantum-dot in a resonator. We show that resonator gain and loss are substantially affected by dephasing- assisted dissipative processes in the quantum-dot system. These additional processes, which go beyond recently proposed polaronic theories, are in good quantitative agreement with experimental observations.

Position-dependent mass, finite-gap systems, and supersymmetry

NASA Astrophysics Data System (ADS)

Bravo, Rafael; Plyushchay, Mikhail S.

2016-05-01

The ordering problem in quantum systems with position-dependent mass (PDM) is treated by inclusion of the classically fictitious similarity transformation into the kinetic term. This provides a generation of supersymmetry with the first-order supercharges from the kinetic term alone, while inclusion of the potential term allows us also to generate nonlinear supersymmetry with higher-order supercharges. A broad class of finite-gap systems with PDM is obtained by different reduction procedures, and general results on supersymmetry generation are applied to them. We show that elliptic finite-gap systems of Lamé and Darboux-Treibich-Verdier types can be obtained by reduction to Seiffert's spherical spiral and Bernoulli lemniscate in the presence of Calogero-like or harmonic oscillator potentials, or by angular momentum reduction of a free motion on some AdS2 -related surfaces in the presence of Aharonov-Bohm flux. The limiting cases include the Higgs and Mathews-Lakshmanan oscillator models as well as a reflectionless model with PDM exploited recently in the discussion of cosmological inflationary scenarios.

A critical evaluation of two-equation models for near wall turbulence

NASA Technical Reports Server (NTRS)

Speziale, Charles G.; Abid, Ridha; Anderson, E. Clay

1990-01-01

A variety of two-equation turbulence models,including several versions of the K-epsilon model as well as the K-omega model, are analyzed critically for near wall turbulent flows from a theoretical and computational standpoint. It is shown that the K-epsilon model has two major problems associated with it: the lack of natural boundary conditions for the dissipation rate and the appearance of higher-order correlations in the balance of terms for the dissipation rate at the wall. In so far as the former problem is concerned, either physically inconsistent boundary conditions have been used or the boundary conditions for the dissipation rate have been tied to higher-order derivatives of the turbulent kinetic energy which leads to numerical stiffness. The K-omega model can alleviate these problems since the asymptotic behavior of omega is known in more detail and since its near wall balance involves only exact viscous terms. However, the modeled form of the omega equation that is used in the literature is incomplete-an exact viscous term is missing which causes the model to behave in an asymptotically inconsistent manner. By including this viscous term and by introducing new wall damping functions with improved asymptotic behavior, a new K-tau model (where tau is identical with 1/omega is turbulent time scale) is developed. It is demonstrated that this new model is computationally robust and yields improved predictions for turbulent boundary layers.

The photon content of the proton

NASA Astrophysics Data System (ADS)

Manohar, Aneesh V.; Nason, Paolo; Salam, Gavin P.; Zanderighi, Giulia

2017-12-01

The photon PDF of the proton is needed for precision comparisons of LHC cross sections with theoretical predictions. In a recent paper, we showed how the photon PDF could be determined in terms of the electromagnetic proton structure functions F 2 and F L measured in electron-proton scattering experiments, and gave an explicit formula for the PDF including all terms up to next-to-leading order. In this paper we give details of the derivation. We obtain the photon PDF using the factorisation theorem and applying it to suitable BSM hard scattering processes. We also obtain the same PDF in a process-independent manner using the usual definition of PDFs in terms of light-cone Fourier transforms of products of operators. We show how our method gives an exact representation for the photon PDF in terms of F 2 and F L , valid to all orders in QED and QCD, and including all non-perturbative corrections. This representation is then used to give an explicit formula for the photon PDF to one order higher than our previous result. We also generalise our results to obtain formulæ for the polarised photon PDF, as well as the photon TMDPDF. Using our formula, we derive the P γ i subset of DGLAP splitting functions to order αα s and α 2, which agree with known results. We give a detailed explanation of the approach that we follow to determine a photon PDF and its uncertainty within the above framework.

Some implementational issues of convection schemes for finite volume formulations

NASA Technical Reports Server (NTRS)

Thakur, Siddharth; Shyy, Wei

1993-01-01

Two higher-order upwind schemes - second-order upwind and QUICK - are examined in terms of their interpretation, implementation as well as performance for a recirculating flow in a lid-driven cavity, in the context of a control volume formulation using the SIMPLE algorithm. The present formulation of these schemes is based on a unified framework wherein the first-order upwind scheme is chosen as the basis, with the remaining terms being assigned to the source term. The performance of these schemes is contrasted with the first-order upwind and second-order central difference schemes. Also addressed in this study is the issue of boundary treatment associated with these higher-order upwind schemes. Two different boundary treatments - one that uses a two-point scheme consistently within a given control volume at the boundary, and the other that maintains consistency of flux across the interior face between the adjacent control volumes - are formulated and evaluated.

Some implementational issues of convection schemes for finite-volume formulations

NASA Technical Reports Server (NTRS)

Thakur, Siddharth; Shyy, Wei

1993-01-01

Two higher-order upwind schemes - second-order upwind and QUICK - are examined in terms of their interpretation, implementations, as well as performance for a recirculating flow in a lid-driven cavity, in the context of a control-volume formulation using the SIMPLE algorithm. The present formulation of these schemes is based on a unified framework wherein the first-order upwind scheme is chosen as the basis, with the remaining terms being assigned to the source term. The performance of these schemes is contrasted with the first-order upwind and second-order central difference schemes. Also addressed in this study is the issue of boundary treatment associated with these higher-order upwind schemes. Two different boundary treatments - one that uses a two-point scheme consistently within a given control volume at the boundary, and the other that maintains consistency of flux across the interior face between the adjacent control volumes - are formulated and evaluated.

The generalized fracture criteria based on the multi-parameter representation of the crack tip stress field

NASA Astrophysics Data System (ADS)

Stepanova, L. V.

2017-12-01

The paper is devoted to the multi-parameter asymptotic description of the stress field near the crack tip of a finite crack in an infinite isotropic elastic plane medium subject to 1) tensile stress; 2) in-plane shear; 3) mixed mode loading for a wide range of mode-mixity situations (Mode I and Mode II). The multi-parameter series expansion of stress tensor components containing higher-order terms is obtained. All the coefficients of the multiparameter series expansion of the stress field are given. The main focus is on the discussion of the influence of considering the higher-order terms of the Williams expansion. The analysis of the higher-order terms in the stress field is performed. It is shown that the larger the distance from the crack tip, the more terms it is necessary to keep in the asymptotic series expansion. Therefore, it can be concluded that several more higher-order terms of the Williams expansion should be used for the stress field description when the distance from the crack tip is not small enough. The crack propagation direction angle is calculated. Two fracture criteria, the maximum tangential stress criterion and the strain energy density criterion, are used. The multi-parameter form of the two commonly used fracture criteria is introduced and tested. Thirty and more terms of the Williams series expansion for the near-crack-tip stress field enable the angle to be calculated more precisely.

Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings

NASA Astrophysics Data System (ADS)

Bordin, Lorenzo; Cabass, Giovanni; Creminelli, Paolo; Vernizzi, Filippo

2017-09-01

We study generalized disformal transformations, including derivatives of the metric, in the context of the Effective Field Theory of Inflation. All these transformations do not change the late-time cosmological observables but change the coefficients of the operators in the action: some couplings are effectively redundant. At leading order in derivatives and up to cubic order in perturbations, one has 6 free functions that can be used to set to zero 6 of the 17 operators at this order. This is used to show that the tensor three-point function cannot be modified at leading order in derivatives, while the scalar-tensor-tensor correlator can only be modified by changing the scalar dynamics. At higher order in derivatives there are transformations that do not affect the Einstein-Hilbert action: one can find 6 additional transformations that can be used to simplify the inflaton action, at least when the dynamics is dominated by the lowest derivative terms. We also identify the leading higher-derivative corrections to the tensor power spectrum and bispectrum.

Carrier recombination mechanisms and efficiency droop in GaInN/GaN light-emitting diodes

DOE PAGES

Dai, Qi; Shan, Qifeng; Wang, Jing; ...

2010-09-30

In this work, we model the carrier recombination mechanisms in GaInN/GaN light-emitting diodes as R=An+Bn 2+Cn 3+f(n), where f(n) represents carrier leakage out of the active region. The term f(n) is expanded into a power series and shown to have higher-than-third-order contributions to the recombination. The total third-order nonradiative coefficient (which may include an f(n) leakage contribution and an Auger contribution) is found to be 8×10 -29 cm 6 s -1. Finally, comparison of the theoretical ABC+f(n) model with experimental data shows that a good fit requires the inclusion of the f(n) term.

On non-BPS effective actions of string theory

NASA Astrophysics Data System (ADS)

Hatefi, Ehsan

2018-05-01

We discuss some physical prospective of the non-BPS effective actions of type IIA and IIB superstring theories. By dealing with all complete three and four point functions, including a closed Ramond-Ramond string (in terms of both its field strength and its potential), gauge (scalar) fields as well as a real tachyon and under symmetry structures, we find various restricted world volume and bulk Bianchi identities. The complete forms of the non-BPS scattering amplitudes including their Chan-Paton factors are elaborated. All the singularity structures of the non-BPS amplitudes, their all order α ' higher-derivative corrections, their contact terms and various modified Bianchi identities are derived. Finally, we show that scattering amplitudes computed in different super-ghost pictures are compatible when suitable Bianchi identities are imposed on the Ramond-Ramond fields. Moreover, we argue that the higher-derivative expansion in powers of the momenta of the tachyon is universal.

Chirped femtosecond pulses in the higher-order nonlinear Schrödinger equation with non-Kerr nonlinear terms and cubic-quintic-septic nonlinearities

NASA Astrophysics Data System (ADS)

Triki, Houria; Biswas, Anjan; Milović, Daniela; Belić, Milivoj

2016-05-01

We consider a high-order nonlinear Schrödinger equation with competing cubic-quintic-septic nonlinearities, non-Kerr quintic nonlinearity, self-steepening, and self-frequency shift. The model describes the propagation of ultrashort (femtosecond) optical pulses in highly nonlinear optical fibers. A new ansatz is adopted to obtain nonlinear chirp associated with the propagating femtosecond soliton pulses. It is shown that the resultant elliptic equation of the problem is of high order, contains several new terms and is more general than the earlier reported results, thus providing a systematic way to find exact chirped soliton solutions of the septic model. Novel soliton solutions, including chirped bright, dark, kink and fractional-transform soliton solutions are obtained for special choices of parameters. Furthermore, we present the parameter domains in which these optical solitons exist. The nonlinear chirp associated with each of the solitonic solutions is also determined. It is shown that the chirping is proportional to the intensity of the wave and depends on higher-order nonlinearities. Of special interest is the soliton solution of the bright and dark type, determined for the general case when all coefficients in the equation have nonzero values. These results can be useful for possible chirped-soliton-based applications of highly nonlinear optical fiber systems.

Apparatus, Method and Program Storage Device for Determining High-Energy Neutron/Ion Transport to a Target of Interest

NASA Technical Reports Server (NTRS)

Wilson, John W. (Inventor); Tripathi, Ram K. (Inventor); Cucinotta, Francis A. (Inventor); Badavi, Francis F. (Inventor)

2012-01-01

An apparatus, method and program storage device for determining high-energy neutron/ion transport to a target of interest. Boundaries are defined for calculation of a high-energy neutron/ion transport to a target of interest; the high-energy neutron/ion transport to the target of interest is calculated using numerical procedures selected to reduce local truncation error by including higher order terms and to allow absolute control of propagated error by ensuring truncation error is third order in step size, and using scaling procedures for flux coupling terms modified to improve computed results by adding a scaling factor to terms describing production of j-particles from collisions of k-particles; and the calculated high-energy neutron/ion transport is provided to modeling modules to control an effective radiation dose at the target of interest.

The Gaussian streaming model and convolution Lagrangian effective field theory

DOE PAGES

Vlah, Zvonimir; Castorina, Emanuele; White, Martin

2016-12-05

We update the ingredients of the Gaussian streaming model (GSM) for the redshift-space clustering of biased tracers using the techniques of Lagrangian perturbation theory, effective field theory (EFT) and a generalized Lagrangian bias expansion. After relating the GSM to the cumulant expansion, we present new results for the real-space correlation function, mean pairwise velocity and pairwise velocity dispersion including counter terms from EFT and bias terms through third order in the linear density, its leading derivatives and its shear up to second order. We discuss the connection to the Gaussian peaks formalism. We compare the ingredients of the GSM tomore » a suite of large N-body simulations, and show the performance of the theory on the low order multipoles of the redshift-space correlation function and power spectrum. We highlight the importance of a general biasing scheme, which we find to be as important as higher-order corrections due to non-linear evolution for the halos we consider on the scales of interest to us.« less

Relativistic wide-angle galaxy bispectrum on the light cone

NASA Astrophysics Data System (ADS)

Bertacca, Daniele; Raccanelli, Alvise; Bartolo, Nicola; Liguori, Michele; Matarrese, Sabino; Verde, Licia

2018-01-01

Given the important role that the galaxy bispectrum has recently acquired in cosmology and the scale and precision of forthcoming galaxy clustering observations, it is timely to derive the full expression of the large-scale bispectrum going beyond approximated treatments which neglect integrated terms or higher-order bias terms or use the Limber approximation. On cosmological scales, relativistic effects that arise from observing the past light cone alter the observed galaxy number counts, therefore leaving their imprints on N-point correlators at all orders. In this paper we compute for the first time the bispectrum including all general relativistic, local and integrated, effects at second order, the tracers' bias at second order, geometric effects as well as the primordial non-Gaussianity contribution. This is timely considering that future surveys will probe scales comparable to the horizon where approximations widely used currently may not hold; neglecting these effects may introduce biases in estimation of cosmological parameters as well as primordial non-Gaussianity.

The Gaussian streaming model and convolution Lagrangian effective field theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vlah, Zvonimir; Castorina, Emanuele; White, Martin, E-mail: zvlah@stanford.edu, E-mail: ecastorina@berkeley.edu, E-mail: mwhite@berkeley.edu

We update the ingredients of the Gaussian streaming model (GSM) for the redshift-space clustering of biased tracers using the techniques of Lagrangian perturbation theory, effective field theory (EFT) and a generalized Lagrangian bias expansion. After relating the GSM to the cumulant expansion, we present new results for the real-space correlation function, mean pairwise velocity and pairwise velocity dispersion including counter terms from EFT and bias terms through third order in the linear density, its leading derivatives and its shear up to second order. We discuss the connection to the Gaussian peaks formalism. We compare the ingredients of the GSM tomore » a suite of large N-body simulations, and show the performance of the theory on the low order multipoles of the redshift-space correlation function and power spectrum. We highlight the importance of a general biasing scheme, which we find to be as important as higher-order corrections due to non-linear evolution for the halos we consider on the scales of interest to us.« less

On the loop approximation in nucleon QCD sum rules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drukarev, E. G., E-mail: drukarev@thd.pnpi.spb.ru; Ryskin, M. G.; Sadovnikova, V. A.

There was a general belief that the nucleon QCD sum rules which include only the quark loops and thus contain only the condensates of dimension d = 3 and d = 4 have only a trivial solution. We demonstrate that there is also a nontrivial solution. We show that it can be treated as the lowest order approximation to the solution which includes the higher terms of the Operator Product Expansion. Inclusion of the radiative corrections improves the convergence of the series.

Optimal guidance law development for an advanced launch system

NASA Technical Reports Server (NTRS)

Calise, Anthony J.; Hodges, Dewey H.

1990-01-01

A regular perturbation analysis is presented. Closed-loop simulations were performed with a first order correction including all of the atmospheric terms. In addition, a method was developed for independently checking the accuracy of the analysis and the rather extensive programming required to implement the complete first order correction with all of the aerodynamic effects included. This amounted to developing an equivalent Hamiltonian computed from the first order analysis. A second order correction was also completed for the neglected spherical Earth and back-pressure effects. Finally, an analysis was begun on a method for dealing with control inequality constraints. The results on including higher order corrections do show some improvement for this application; however, it is not known at this stage if significant improvement will result when the aerodynamic forces are included. The weak formulation for solving optimal problems was extended in order to account for state inequality constraints. The formulation was tested on three example problems and numerical results were compared to the exact solutions. Development of a general purpose computational environment for the solution of a large class of optimal control problems is under way. An example, along with the necessary input and the output, is given.

Long Periodic Terms in the Solar System

NASA Technical Reports Server (NTRS)

Bretagnon, P.

1982-01-01

The long period variations of the first eight planets in the solar system are studied. First, the Lagrangian solution is calculated and then the long period terms with fourth order eccentricities and inclinations are introduced into the perturbation function. A second approximation was made taking into account the short period terms' contribution, namely the perturbations of first order with respect to the masses. Special attention was paid to the determination of the integration constants. The relative importance of the different contributions is shown. It is useless, for example, to introduce the long period terms of fifth order if no account has been taken of the short period terms. Meanwhile, the terms that have been neglected would not introduce large changes in the integration constants. Even so, the calculation should be repeated with higher order short period terms and fifth order long periods.

Variable High Order Multiblock Overlapping Grid Methods for Mixed Steady and Unsteady Multiscale Viscous Flows

NASA Technical Reports Server (NTRS)

Sjogreen, Bjoern; Yee, H. C.

2007-01-01

Flows containing steady or nearly steady strong shocks in parts of the flow field, and unsteady turbulence with shocklets on other parts of the flow field are difficult to capture accurately and efficiently employing the same numerical scheme even under the multiblock grid or adaptive grid refinement framework. On one hand, sixth-order or higher shock-capturing methods are appropriate for unsteady turbulence with shocklets. On the other hand, lower order shock-capturing methods are more effective for strong steady shocks in terms of convergence. In order to minimize the shortcomings of low order and high order shock-capturing schemes for the subject flows,a multi- block overlapping grid with different orders of accuracy on different blocks is proposed. Test cases to illustrate the performance of the new solver are included.

The effects of finite rate chemical processes on high enthalpy nozzle performance - A comparison between SPARK and SEAGULL

NASA Technical Reports Server (NTRS)

Carpenter, M. H.

1988-01-01

The generalized chemistry version of the computer code SPARK is extended to include two higher-order numerical schemes, yielding fourth-order spatial accuracy for the inviscid terms. The new and old formulations are used to study the influences of finite rate chemical processes on nozzle performance. A determination is made of the computationally optimum reaction scheme for use in high-enthalpy nozzles. Finite rate calculations are compared with the frozen and equilibrium limits to assess the validity of each formulation. In addition, the finite rate SPARK results are compared with the constant ratio of specific heats (gamma) SEAGULL code, to determine its accuracy in variable gamma flow situations. Finally, the higher-order SPARK code is used to calculate nozzle flows having species stratification. Flame quenching occurs at low nozzle pressures, while for high pressures, significant burning continues in the nozzle.

Symmetries, invariants and generating functions: higher-order statistics of biased tracers

NASA Astrophysics Data System (ADS)

Munshi, Dipak

2018-01-01

Gravitationally collapsed objects are known to be biased tracers of an underlying density contrast. Using symmetry arguments, generalised biasing schemes have recently been developed to relate the halo density contrast δh with the underlying density contrast δ, divergence of velocity θ and their higher-order derivatives. This is done by constructing invariants such as s, t, ψ,η. We show how the generating function formalism in Eulerian standard perturbation theory (SPT) can be used to show that many of the additional terms based on extended Galilean and Lifshitz symmetry actually do not make any contribution to the higher-order statistics of biased tracers. Other terms can also be drastically simplified allowing us to write the vertices associated with δh in terms of the vertices of δ and θ, the higher-order derivatives and the bias coefficients. We also compute the cumulant correlators (CCs) for two different tracer populations. These perturbative results are valid for tree-level contributions but at an arbitrary order. We also take into account the stochastic nature bias in our analysis. Extending previous results of a local polynomial model of bias, we express the one-point cumulants Script SN and their two-point counterparts, the CCs i.e. Script Cpq, of biased tracers in terms of that of their underlying density contrast counterparts. As a by-product of our calculation we also discuss the results using approximations based on Lagrangian perturbation theory (LPT).

Real-time approximate optimal guidance laws for the advanced launch system

NASA Technical Reports Server (NTRS)

Speyer, Jason L.; Feeley, Timothy; Hull, David G.

1989-01-01

An approach to optimal ascent guidance for a launch vehicle is developed using an expansion technique. The problem is to maximize the payload put into orbit subject to the equations of motion of a rocket over a rotating spherical earth. It is assumed that the thrust and gravitational forces dominate over the aerodynamic forces. It is shown that these forces can be separated by a small parameter epsilon, where epsilon is the ratio of the atmospheric scale height to the radius of the earth. The Hamilton-Jacobi-Bellman or dynamic programming equation is expanded in a series where the zeroth-order term (epsilon = 0) can be obtained in closed form. The zeroth-order problem is that of putting maximum payload into orbit subject to the equations of motion of a rocket in a vacuum over a flat earth. The neglected inertial and aerodynamic terms are included in higher order terms of the expansion, which are determined from the solution of first-order linear partial differential equations requiring only quadrature integrations. These quadrature integrations can be performed rapidly, so that real-time approximate optimization can be used to construct the launch guidance law.

Time-varying higher order spectra

NASA Astrophysics Data System (ADS)

Boashash, Boualem; O'Shea, Peter

1991-12-01

A general solution for the problem of time-frequency signal representation of nonlinear FM signals is provided, based on a generalization of the Wigner-Ville distribution. The Wigner- Ville distribution (WVD) is a second order time-frequency representation. That is, it is able to give ideal energy concentration for quadratic phase signals and its ensemble average is a second order time-varying spectrum. The same holds for Cohen's class of time-frequency distributions, which are smoothed versions of the WVD. The WVD may be extended so as to achieve ideal energy concentration for higher order phase laws, and such that the expectation is a time-varying higher order spectrum. The usefulness of these generalized Wigner-Ville distributions (GWVD) is twofold. Firstly, because they achieve ideal energy concentration for polynomial phase signals, they may be used for optimal instantaneous frequency estimation. Second, they are useful for discriminating between nonstationary processes of differing higher order moments. In the same way that the WVD is generalized, we generalize Cohen's class of TFDs by defining a class of generalized time-frequency distributions (GTFDs) obtained by a two dimensional smoothing of the GWVD. Another results derived from this approach is a method based on higher order spectra which allows the separation of cross-terms and auto- terms in the WVD.

The refractive index in electron microscopy and the errors of its approximations.

PubMed

Lentzen, M

2017-05-01

In numerical calculations for electron diffraction often a simplified form of the electron-optical refractive index, linear in the electric potential, is used. In recent years improved calculation schemes have been proposed, aiming at higher accuracy by including higher-order terms of the electric potential. These schemes start from the relativistically corrected Schrödinger equation, and use a second simplified form, now for the refractive index squared, being linear in the electric potential. The second and higher-order corrections thus determined have, however, a large error, compared to those derived from the relativistically correct refractive index. The impact of the two simplifications on electron diffraction calculations is assessed through numerical comparison of the refractive index at high-angle Coulomb scattering and of cross-sections for a wide range of scattering angles, kinetic energies, and atomic numbers. Copyright © 2016 Elsevier B.V. All rights reserved.

Aberrated laser beams in terms of Zernike polynomials

NASA Astrophysics Data System (ADS)

Alda, Javier; Alonso, Jose; Bernabeu, Eusebio

1996-11-01

The characterization of light beams has devoted a lot of attention in the past decade. Several formalisms have been presented to treat the problem of parameter invariance and characterization in the propagation of light beam along ideal, ABCD, optical systems. The hard and soft apertured optical systems have been treated too. Also some aberrations have been analyzed, but it has not appeared a formalism able to treat the problem as a whole. In this contribution we use a classical approach to describe the problem of aberrated, and therefore apertured, light beams. The wavefront aberration is included in a pure phase term expanded in terms of the Zernike polynomials. Then, we can use the relation between the lower order Zernike polynomia and the Seidel or third order aberrations. We analyze the astigmatism, the spherical aberration and the coma, and we show how higher order aberrations can be taken into account. We have calculated the divergence, and the radius of curvature of such aberrated beams and the influence of these aberrations in the quality of the light beam. Some numerical simulations have been done to illustrate the method.

A real-time approximate optimal guidance law for flight in a plane

NASA Technical Reports Server (NTRS)

Feeley, Timothy S.; Speyer, Jason L.

1990-01-01

A real-time guidance scheme is presented for the problem of maximizing the payload into orbit subject to the equations of motion of a rocket over a nonrotating spherical earth. The flight is constrained to a path in the equatorial plane while reaching an orbital altitude at orbital injection speeds. The dynamics of the problem can be separated into primary and perturbation effects by a small parameter, epsilon, which is the ratio of the atmospheric scale height to the radius of the earth. The Hamilton-Jacobi-Bellman or dynamic programming equation is expanded in an asymptotic series where the zeroth-order term (epsilon = 0) can be obtained in closed form. The neglected perturbation terms are included in the higher-order terms of the expansion, which are determined from the solution of first-order linear partial differential equations requiring only integrations which are quadratures. The quadratures can be performed rapidly with emerging computer capability, so that real-time approximate optimization can be used to construct the launch guidance law. The application of this technique to flight in three-dimensions is made apparent from the solution presented.

Electron acceleration by a tightly focused Hermite-Gaussian beam: higher-order corrections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao Zhiguo; Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064; Yang Dangxiao

2008-03-15

Taking the TEM{sub 1,0}-mode Hermite-Gaussian (H-G) beam as a numerical calculation example, and based on the method of the perturbation series expansion, the higher-order field corrections of H-G beams are derived and used to study the electron acceleration by a tightly focused H-G beam in vacuum. For the case of the off-axis injection the field corrections to the terms of order f{sup 3} (f=1/kw{sub 0}, k and w{sub 0} being the wavenumber and waist width, respectively) are considered, and for the case of the on-axis injection the contributions of the terms of higher orders are negligible. By a suitable optimizationmore » of injection parameters the energy gain in the giga-electron-volt regime can be achieved.« less

A Generalization of Snell’s Law

DTIC Science & Technology

1990-06-01

Weinstock [Ref. 2:pp. 20-22]. We know that f(x+h) - f(x) = f’(x)h + higher order terms in h. We apply this to our simplest variational problem by considering...higher order terms . We also define 6J[h] to be the first variation : 8J[h] =f’b (Fy h + Fyh ’)& Setting the first variation equal to zero, and integrating...tC.’~.’’ 82 16. SUPPLEMENTARY NOTATION o r-’ ~ A I~ ~rt~i ra -Ir C’t t.t ) o 17, COSATI CODES 18, SyBJECT TERMS (Continue on reverse if necessary

On push-forward representations in the standard gyrokinetic model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyato, N., E-mail: miyato.naoaki@jaea.go.jp; Yagi, M.; Scott, B. D.

2015-01-15

Two representations of fluid moments in terms of a gyro-center distribution function and gyro-center coordinates, which are called push-forward representations, are compared in the standard electrostatic gyrokinetic model. In the representation conventionally used to derive the gyrokinetic Poisson equation, the pull-back transformation of the gyro-center distribution function contains effects of the gyro-center transformation and therefore electrostatic potential fluctuations, which is described by the Poisson brackets between the distribution function and scalar functions generating the gyro-center transformation. Usually, only the lowest order solution of the generating function at first order is considered to explicitly derive the gyrokinetic Poisson equation. This ismore » true in explicitly deriving representations of scalar fluid moments with polarization terms. One also recovers the particle diamagnetic flux at this order because it is associated with the guiding-center transformation. However, higher-order solutions are needed to derive finite Larmor radius terms of particle flux including the polarization drift flux from the conventional representation. On the other hand, the lowest order solution is sufficient for the other representation, in which the gyro-center transformation part is combined with the guiding-center one and the pull-back transformation of the distribution function does not appear.« less

Thermodynamics of higher dimensional black holes with higher order thermal fluctuations

NASA Astrophysics Data System (ADS)

Pourhassan, B.; Kokabi, K.; Rangyan, S.

2017-12-01

In this paper, we consider higher order corrections of the entropy, which coming from thermal fluctuations, and find their effect on the thermodynamics of higher dimensional charged black holes. Leading order thermal fluctuation is logarithmic term in the entropy while higher order correction is proportional to the inverse of original entropy. We calculate some thermodynamics quantities and obtain the effect of logarithmic and higher order corrections of entropy on them. Validity of the first law of thermodynamics investigated and Van der Waals equation of state of dual picture studied. We find that five-dimensional black hole behaves as Van der Waals, but higher dimensional case have not such behavior. We find that thermal fluctuations are important in stability of black hole hence affect unstable/stable black hole phase transition.

Fitting Prony Series To Data On Viscoelastic Materials

NASA Technical Reports Server (NTRS)

Hill, S. A.

1995-01-01

Improved method of fitting Prony series to data on viscoelastic materials involves use of least-squares optimization techniques. Based on optimization techniques yields closer correlation with data than traditional method. Involves no assumptions regarding the gamma'(sub i)s and higher-order terms, and provides for as many Prony terms as needed to represent higher-order subtleties in data. Curve-fitting problem treated as design-optimization problem and solved by use of partially-constrained-optimization techniques.

Constraints on tree-level higher order gravitational couplings in superstring theory.

PubMed

Stieberger, Stephan

2011-03-18

We consider the scattering amplitudes of five and six gravitons at tree level in superstring theory. Their power series expansions in the Regge slope α' are analyzed through the order α'(8) showing some interesting constraints on higher order gravitational couplings in the effective superstring action such as the absence of R(5) terms. Furthermore, some transcendentality constraints on the coefficients of the nonvanishing couplings are observed: the absence of zeta values of even weight through the order α'(8) like the absence of ζ(2)ζ(3)R(6) terms. Our analysis is valid for any superstring background in any space-time dimension, which allows for a conformal field theory description.

The consequences of improperly describing oscillator strengths beyond the electric dipole approximation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lestrange, Patrick J.; Egidi, Franco; Li, Xiaosong, E-mail: xsli@uw.edu

2015-12-21

The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strengthmore » can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities.« less

The consequences of improperly describing oscillator strengths beyond the electric dipole approximation.

PubMed

Lestrange, Patrick J; Egidi, Franco; Li, Xiaosong

2015-12-21

The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities.

The consequences of improperly describing oscillator strengths beyond the electric dipole approximation

NASA Astrophysics Data System (ADS)

Lestrange, Patrick J.; Egidi, Franco; Li, Xiaosong

2015-12-01

The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities.

SCL-90-R emotional distress ratings in substance use and impulse control disorders: One-factor, oblique first-order, higher-order, and bi-factor models compared.

PubMed

Arrindell, Willem A; Urbán, Róbert; Carrozzino, Danilo; Bech, Per; Demetrovics, Zsolt; Roozen, Hendrik G

2017-09-01

To fully understand the dimensionality of an instrument in a certain population, rival bi-factor models should be routinely examined and tested against oblique first-order and higher-order structures. The present study is among the very few studies that have carried out such a comparison in relation to the Symptom Checklist-90-R. In doing so, it utilized a sample comprising 2593 patients with substance use and impulse control disorders. The study also included a test of a one-dimensional model of general psychological distress. Oblique first-order factors were based on the original a priori 9-dimensional model advanced by Derogatis (1977); and on an 8-dimensional model proposed by Arrindell and Ettema (2003)-Agoraphobia, Anxiety, Depression, Somatization, Cognitive-performance deficits, Interpersonal sensitivity and mistrust, Acting-out hostility, and Sleep difficulties. Taking individual symptoms as input, three higher-order models were tested with at the second-order levels either (1) General psychological distress; (2) 'Panic with agoraphobia', 'Depression' and 'Extra-punitive behavior'; or (3) 'Irritable-hostile depression' and 'Panic with agoraphobia'. In line with previous studies, no support was found for the one-factor model. Bi-factor models were found to fit the dataset best relative to the oblique first-order and higher-order models. However, oblique first-order and higher-order factor models also fit the data fairly well in absolute terms. Higher-order solution (2) provided support for R.F. Krueger's empirical model of psychopathology which distinguishes between fear, distress, and externalizing factors (Krueger, 1999). The higher-order model (3), which combines externalizing and distress factors (Irritable-hostile depression), fit the data numerically equally well. Overall, findings were interpreted as supporting the hypothesis that the prevalent forms of symptomatology addressed have both important common and unique features. Proposals were made to improve the Depression subscale as its scores represent more of a very common construct as is measured with the severity (total) scale than of a specific measure that purports to measure what it should assess-symptoms of depression. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Higher order QCD predictions for associated Higgs production with anomalous couplings to gauge bosons

NASA Astrophysics Data System (ADS)

Mimasu, Ken; Sanz, Verónica; Williams, Ciaran

2016-08-01

We present predictions for the associated production of a Higgs boson at NLO+PS accuracy, including the effect of anomalous interactions between the Higgs and gauge bosons. We present our results in different frameworks, one in which the interaction vertex between the Higgs boson and Standard Model W and Z bosons is parameterized in terms of general Lorentz structures, and one in which Electroweak symmetry breaking is manifestly linear and the resulting operators arise through a six-dimensional effective field theory framework. We present analytic calculations of the Standard Model and Beyond the Standard Model contributions, and discuss the phenomenological impact of the higher order pieces. Our results are implemented in the NLO Monte Carlo program MCFM, and interfaced to shower Monte Carlos through the Powheg box framework.

The Effect of Inhibitory Neuron on the Evolution Model of Higher-Order Coupling Neural Oscillator Population

PubMed Central

Qi, Yi; Wang, Rubin; Jiao, Xianfa; Du, Ying

2014-01-01

We proposed a higher-order coupling neural network model including the inhibitory neurons and examined the dynamical evolution of average number density and phase-neural coding under the spontaneous activity and external stimulating condition. The results indicated that increase of inhibitory coupling strength will cause decrease of average number density, whereas increase of excitatory coupling strength will cause increase of stable amplitude of average number density. Whether the neural oscillator population is able to enter the new synchronous oscillation or not is determined by excitatory and inhibitory coupling strength. In the presence of external stimulation, the evolution of the average number density is dependent upon the external stimulation and the coupling term in which the dominator will determine the final evolution. PMID:24516505

Optical design with Wood lenses

NASA Astrophysics Data System (ADS)

Caldwell, J. Brian

1991-01-01

Spherical aberration in a flat surfaced radial gradient-index lens (a Wood lens) with a parabolic index profile can be corrected by altering the profile to Include higher order terms. However this results in a large amowfl of third order coma. This paper presents an alternative method of aberration correction similar to that used in the catadiopthc Schmidtsystem. A Wood lens with a parabolic profile is used to provide all or most of the optical power. Coma is corrected by stop shifting and Spherical aberration is corrected by placing a powerless Wood lens corrector plate at the stop. 1.

Simplifying the EFT of Inflation: generalized disformal transformations and redundant couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bordin, Lorenzo; Cabass, Giovanni; Creminelli, Paolo

We study generalized disformal transformations, including derivatives of the metric, in the context of the Effective Field Theory of Inflation. All these transformations do not change the late-time cosmological observables but change the coefficients of the operators in the action: some couplings are effectively redundant. At leading order in derivatives and up to cubic order in perturbations, one has 6 free functions that can be used to set to zero 6 of the 17 operators at this order. This is used to show that the tensor three-point function cannot be modified at leading order in derivatives, while the scalar-tensor-tensor correlatormore » can only be modified by changing the scalar dynamics. At higher order in derivatives there are transformations that do not affect the Einstein-Hilbert action: one can find 6 additional transformations that can be used to simplify the inflaton action, at least when the dynamics is dominated by the lowest derivative terms. We also identify the leading higher-derivative corrections to the tensor power spectrum and bispectrum.« less

Distribution function approach to redshift space distortions. Part IV: perturbation theory applied to dark matter

NASA Astrophysics Data System (ADS)

Vlah, Zvonimir; Seljak, Uroš; McDonald, Patrick; Okumura, Teppei; Baldauf, Tobias

2012-11-01

We develop a perturbative approach to redshift space distortions (RSD) using the phase space distribution function approach and apply it to the dark matter redshift space power spectrum and its moments. RSD can be written as a sum over density weighted velocity moments correlators, with the lowest order being density, momentum density and stress energy density. We use standard and extended perturbation theory (PT) to determine their auto and cross correlators, comparing them to N-body simulations. We show which of the terms can be modeled well with the standard PT and which need additional terms that include higher order corrections which cannot be modeled in PT. Most of these additional terms are related to the small scale velocity dispersion effects, the so called finger of god (FoG) effects, which affect some, but not all, of the terms in this expansion, and which can be approximately modeled using a simple physically motivated ansatz such as the halo model. We point out that there are several velocity dispersions that enter into the detailed RSD analysis with very different amplitudes, which can be approximately predicted by the halo model. In contrast to previous models our approach systematically includes all of the terms at a given order in PT and provides a physical interpretation for the small scale dispersion values. We investigate RSD power spectrum as a function of μ, the cosine of the angle between the Fourier mode and line of sight, focusing on the lowest order powers of μ and multipole moments which dominate the observable RSD power spectrum. Overall we find considerable success in modeling many, but not all, of the terms in this expansion. This is similar to the situation in real space, but predicting power spectrum in redshift space is more difficult because of the explicit influence of small scale dispersion type effects in RSD, which extend to very large scales.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vlah, Zvonimir; Seljak, Uroš; Baldauf, Tobias

We develop a perturbative approach to redshift space distortions (RSD) using the phase space distribution function approach and apply it to the dark matter redshift space power spectrum and its moments. RSD can be written as a sum over density weighted velocity moments correlators, with the lowest order being density, momentum density and stress energy density. We use standard and extended perturbation theory (PT) to determine their auto and cross correlators, comparing them to N-body simulations. We show which of the terms can be modeled well with the standard PT and which need additional terms that include higher order correctionsmore » which cannot be modeled in PT. Most of these additional terms are related to the small scale velocity dispersion effects, the so called finger of god (FoG) effects, which affect some, but not all, of the terms in this expansion, and which can be approximately modeled using a simple physically motivated ansatz such as the halo model. We point out that there are several velocity dispersions that enter into the detailed RSD analysis with very different amplitudes, which can be approximately predicted by the halo model. In contrast to previous models our approach systematically includes all of the terms at a given order in PT and provides a physical interpretation for the small scale dispersion values. We investigate RSD power spectrum as a function of μ, the cosine of the angle between the Fourier mode and line of sight, focusing on the lowest order powers of μ and multipole moments which dominate the observable RSD power spectrum. Overall we find considerable success in modeling many, but not all, of the terms in this expansion. This is similar to the situation in real space, but predicting power spectrum in redshift space is more difficult because of the explicit influence of small scale dispersion type effects in RSD, which extend to very large scales.« less

Modulational instability and dynamics of implicit higher-order rogue wave solutions for the Kundu equation

NASA Astrophysics Data System (ADS)

Wen, Xiao-Yong; Zhang, Guoqiang

2018-01-01

Under investigation in this paper is the Kundu equation, which may be used to describe the propagation process of ultrashort optical pulses in nonlinear optics. The modulational instability of the plane-wave for the possible reason of the formation of the rogue wave (RW) is studied for the system. Based on our proposed generalized perturbation (n,N - n)-fold Darboux transformation (DT), some new higher-order implicit RW solutions in terms of determinants are obtained by means of the generalized perturbation (1,N - 1)-fold DT, when choosing different special parameters, these results will reduce to the RW solutions of the Kaup-Newell (KN) equation, Chen-Lee-Liu (CLL) equation and Gerjikov-Ivanov (GI) equation, respectively. The relevant wave structures are shown graphically, which display abundant interesting wave structures. The dynamical behaviors and propagation stability of the first-order and second-order RW solutions are discussed by using numerical simulations, the higher-order nonlinear terms for the Kundu equation have an impact on the propagation instability of the RW. The method can also be extended to find the higher-order RW or rational solutions of other integrable nonlinear equations.

Predicting Physical Time Series Using Dynamic Ridge Polynomial Neural Networks

PubMed Central

Al-Jumeily, Dhiya; Ghazali, Rozaida; Hussain, Abir

2014-01-01

Forecasting naturally occurring phenomena is a common problem in many domains of science, and this has been addressed and investigated by many scientists. The importance of time series prediction stems from the fact that it has wide range of applications, including control systems, engineering processes, environmental systems and economics. From the knowledge of some aspects of the previous behaviour of the system, the aim of the prediction process is to determine or predict its future behaviour. In this paper, we consider a novel application of a higher order polynomial neural network architecture called Dynamic Ridge Polynomial Neural Network that combines the properties of higher order and recurrent neural networks for the prediction of physical time series. In this study, four types of signals have been used, which are; The Lorenz attractor, mean value of the AE index, sunspot number, and heat wave temperature. The simulation results showed good improvements in terms of the signal to noise ratio in comparison to a number of higher order and feedforward neural networks in comparison to the benchmarked techniques. PMID:25157950

Predicting physical time series using dynamic ridge polynomial neural networks.

PubMed

Al-Jumeily, Dhiya; Ghazali, Rozaida; Hussain, Abir

2014-01-01

Forecasting naturally occurring phenomena is a common problem in many domains of science, and this has been addressed and investigated by many scientists. The importance of time series prediction stems from the fact that it has wide range of applications, including control systems, engineering processes, environmental systems and economics. From the knowledge of some aspects of the previous behaviour of the system, the aim of the prediction process is to determine or predict its future behaviour. In this paper, we consider a novel application of a higher order polynomial neural network architecture called Dynamic Ridge Polynomial Neural Network that combines the properties of higher order and recurrent neural networks for the prediction of physical time series. In this study, four types of signals have been used, which are; The Lorenz attractor, mean value of the AE index, sunspot number, and heat wave temperature. The simulation results showed good improvements in terms of the signal to noise ratio in comparison to a number of higher order and feedforward neural networks in comparison to the benchmarked techniques.

Communication: Understanding molecular representations in machine learning: The role of uniqueness and target similarity

NASA Astrophysics Data System (ADS)

Huang, Bing; von Lilienfeld, O. Anatole

2016-10-01

The predictive accuracy of Machine Learning (ML) models of molecular properties depends on the choice of the molecular representation. Inspired by the postulates of quantum mechanics, we introduce a hierarchy of representations which meet uniqueness and target similarity criteria. To systematically control target similarity, we simply rely on interatomic many body expansions, as implemented in universal force-fields, including Bonding, Angular (BA), and higher order terms. Addition of higher order contributions systematically increases similarity to the true potential energy and predictive accuracy of the resulting ML models. We report numerical evidence for the performance of BAML models trained on molecular properties pre-calculated at electron-correlated and density functional theory level of theory for thousands of small organic molecules. Properties studied include enthalpies and free energies of atomization, heat capacity, zero-point vibrational energies, dipole-moment, polarizability, HOMO/LUMO energies and gap, ionization potential, electron affinity, and electronic excitations. After training, BAML predicts energies or electronic properties of out-of-sample molecules with unprecedented accuracy and speed.

On the complete and partial integrability of non-Hamiltonian systems

NASA Astrophysics Data System (ADS)

Bountis, T. C.; Ramani, A.; Grammaticos, B.; Dorizzi, B.

1984-11-01

The methods of singularity analysis are applied to several third order non-Hamiltonian systems of physical significance including the Lotka-Volterra equations, the three-wave interaction and the Rikitake dynamo model. Complete integrability is defined and new completely integrable systems are discovered by means of the Painlevé property. In all these cases we obtain integrals, which reduce the equations either to a final quadrature or to an irreducible second order ordinary differential equation (ODE) solved by Painlevé transcendents. Relaxing the Painlevé property we find many partially integrable cases whose movable singularities are poles at leading order, with In( t- t0) terms entering at higher orders. In an Nth order, generalized Rössler model a precise relation is established between the partial fulfillment of the Painlevé conditions and the existence of N - 2 integrals of the motion.

Effects of fluid inertia and turbulence on force coefficients for squeeze film dampers

NASA Technical Reports Server (NTRS)

Andres, L. S.; Vance, J. M.

1984-01-01

The effects of fluid inertia and turbulence on the force coefficients of squeeze film dampers are investigated analytically. Both the convective and the temporal terms are included in the analysis of inertia effects. The analysis of turbulence is based on friction coefficients currently found in the literature for Poiseuille flow. The effect of fluid inertia on the magnitude of the radial direct inertia coefficient (i.e., to produce an apparent added mass at small eccentricity ratios, due to the temporal terms) is found to be completely reversed at large eccentricity ratios. The reversal is due entirely to the inclusion of the convective inertia terms in the analysis. Turbulence is found to produce a large effect on the direct damping coefficient at high eccentricity ratios. For the long or sealed squeeze film damper at high eccentricity ratios, the damping prediction with turbulence included is an order of magnitude higher than the laminar solution.

fNL‑gNL mixing in the matter density field at higher orders

NASA Astrophysics Data System (ADS)

Gressel, Hedda A.; Bruni, Marco

2018-06-01

In this paper we examine how primordial non-Gaussianity contributes to nonlinear perturbative orders in the expansion of the density field at large scales in the matter dominated era. General Relativity is an intrinsically nonlinear theory, establishing a nonlinear relation between the metric and the density field. Representing the metric perturbations with the curvature perturbation ζ, it is known that nonlinearity produces effective non-Gaussian terms in the nonlinear perturbations of the matter density field δ, even if the primordial ζ is Gaussian. Here we generalise these results to the case of a non-Gaussian primordial ζ. Using a standard parametrization of primordial non-Gaussianity in ζ in terms of fNL, gNL, hNL\\ldots , we show how at higher order (from third and higher) nonlinearity also produces a mixing of these contributions to the density field at large scales, e.g. both fNL and gNL contribute to the third order in δ. This is the main result of this paper. Our analysis is based on the synergy between a gradient expansion (aka long-wavelength approximation) and standard perturbation theory at higher order. In essence, mathematically the equations for the gradient expansion are equivalent to those of first order perturbation theory, thus first-order results convert into gradient expansion results and, vice versa, the gradient expansion can be used to derive results in perturbation theory at higher order and large scales.

Near-term lander experiments for growing plants on Mars: requirements for information on chemical and physical properties of Mars regolith.

PubMed

Schuerger, Andrew C; Ming, Douglas W; Newsom, Horton E; Ferl, Robert J; McKay, Christopher P

2002-01-01

In order to support humans for long-duration missions to Mars, bioregenerative Advanced Life Support (ALS) systems have been proposed that would use higher plants as the primary candidates for photosynthesis. Hydroponic technologies have been suggested as the primary method of plant production in ALS systems, but the use of Mars regolith as a plant growth medium may have several advantages over hydroponic systems. The advantages for using Mars regolith include the likely bioavailability of plant-essential ions, mechanical support for plants, and easy access of the material once on the surface. We propose that plant biology experiments must be included in near-term Mars lander missions in order to begin defining the optimum approach for growing plants on Mars. Second, we discuss a range of soil chemistry and soil physics tests that must be conducted prior to, or in concert with, a plant biology experiment in order to properly interpret the results of plant growth studies in Mars regolith. The recommended chemical tests include measurements on soil pH, electrical conductivity and soluble salts, redox potential, bioavailability of essential plant nutrients, and bioavailability of phytotoxic elements. In addition, a future plant growth experiment should include procedures for determining the buffering and leaching requirements of Mars regolith prior to planting. Soil physical tests useful for plant biology studies in Mars regolith include bulk density, particle size distribution, porosity, water retention, and hydraulic conductivity.

Near-term lander experiments for growing plants on Mars: requirements for information on chemical and physical properties of Mars regolith

NASA Technical Reports Server (NTRS)

Schuerger, Andrew C.; Ming, Douglas W.; Newsom, Horton E.; Ferl, Robert J.; McKay, Christopher P.

2002-01-01

In order to support humans for long-duration missions to Mars, bioregenerative Advanced Life Support (ALS) systems have been proposed that would use higher plants as the primary candidates for photosynthesis. Hydroponic technologies have been suggested as the primary method of plant production in ALS systems, but the use of Mars regolith as a plant growth medium may have several advantages over hydroponic systems. The advantages for using Mars regolith include the likely bioavailability of plant-essential ions, mechanical support for plants, and easy access of the material once on the surface. We propose that plant biology experiments must be included in near-term Mars lander missions in order to begin defining the optimum approach for growing plants on Mars. Second, we discuss a range of soil chemistry and soil physics tests that must be conducted prior to, or in concert with, a plant biology experiment in order to properly interpret the results of plant growth studies in Mars regolith. The recommended chemical tests include measurements on soil pH, electrical conductivity and soluble salts, redox potential, bioavailability of essential plant nutrients, and bioavailability of phytotoxic elements. In addition, a future plant growth experiment should include procedures for determining the buffering and leaching requirements of Mars regolith prior to planting. Soil physical tests useful for plant biology studies in Mars regolith include bulk density, particle size distribution, porosity, water retention, and hydraulic conductivity.

Deriving Lindblad master equations with Keldysh diagrams: Correlated gain and loss in higher order perturbation theory

NASA Astrophysics Data System (ADS)

Müller, Clemens; Stace, Thomas M.

2017-01-01

Motivated by correlated decay processes producing gain, loss, and lasing in driven semiconductor quantum dots [Phys. Rev. Lett. 113, 036801 (2014), 10.1103/PhysRevLett.113.036801; Science 347, 285 (2015), 10.1126/science.aaa2501; Phys. Rev. Lett. 114, 196802 (2015), 10.1103/PhysRevLett.114.196802], we develop a theoretical technique by using Keldysh diagrammatic perturbation theory to derive a Lindblad master equation that goes beyond the usual second-order perturbation theory. We demonstrate the method on the driven dissipative Rabi model, including terms up to fourth order in the interaction between the qubit and both the resonator and environment. This results in a large class of Lindblad dissipators and associated rates which go beyond the terms that have previously been proposed to describe similar systems. All of the additional terms contribute to the system behavior at the same order of perturbation theory. We then apply these results to analyze the phonon-assisted steady-state gain of a microwave field driving a double quantum dot in a resonator. We show that resonator gain and loss are substantially affected by dephasing-assisted dissipative processes in the quantum-dot system. These additional processes, which go beyond recently proposed polaronic theories, are in good quantitative agreement with experimental observations.

Single-Inclusive Jet Production In Electron-Nucleon Collisions Through Next-To-Next-To-Leading Order In Perturbative QCD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abelof, Gabriel; Boughezal, Radja; Liu, Xiaohui

2016-10-17

We compute the Oσ 2σ 2 s perturbative corrections to inclusive jet production in electron-nucleon collisions. This process is of particular interest to the physics program of a future Electron Ion Collider (EIC). We include all relevant partonic processes, including deep-inelastic scattering contributions, photon-initiated corrections, and parton-parton scattering terms that first appear at this order. Upon integration over the final-state hadronic phase space we validate our results for the deep-inelastic corrections against the known next-to-next-to-leading order (NNLO) structure functions. Our calculation uses the N-jettiness subtraction scheme for performing higher-order computations, and allows for a completely differential description of the deep-inelasticmore » scattering process. We describe the application of this method to inclusive jet production in detail, and present phenomenological results for the proposed EIC. The NNLO corrections have a non-trivial dependence on the jet kinematics and arise from an intricate interplay between all contributing partonic channels.« less

A continued fraction resummation form of bath relaxation effect in the spin-boson model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Zhihao; Tang, Zhoufei; Wu, Jianlan, E-mail: jianlanwu@zju.edu.cn

2015-02-28

In the spin-boson model, a continued fraction form is proposed to systematically resum high-order quantum kinetic expansion (QKE) rate kernels, accounting for the bath relaxation effect beyond the second-order perturbation. In particular, the analytical expression of the sixth-order QKE rate kernel is derived for resummation. With higher-order correction terms systematically extracted from higher-order rate kernels, the resummed quantum kinetic expansion approach in the continued fraction form extends the Pade approximation and can fully recover the exact quantum dynamics as the expansion order increases.

Air transportation energy efficiency - Alternatives and implications

NASA Technical Reports Server (NTRS)

Williams, L. J.

1976-01-01

Results from recent studies of air transportation energy efficiency alternatives are discussed, along with some of the implications of these alternatives. The fuel-saving alternatives considered include aircraft operation, aircraft modification, derivative aircraft, and new aircraft. In the near-term, energy efficiency improvements should be possible through small improvements in fuel-saving flight procedures, higher density seating, and higher load factors. Additional small near-term improvements could be obtained through aircraft modifications, such as the relatively inexpensive drag reduction modifications. Derivatives of existing aircraft could meet the requirements for new aircraft and provide energy improvements until advanced technology is available to justify the cost of a completely new design. In order to obtain significant improvements in energy efficiency, new aircraft must truly exploit advanced technology in such areas as aerodynamics, composite structures, active controls, and advanced propulsion.

CMB spectral distortions as solutions to the Boltzmann equations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ota, Atsuhisa, E-mail: a.ota@th.phys.titech.ac.jp

2017-01-01

We propose to re-interpret the cosmic microwave background spectral distortions as solutions to the Boltzmann equation. This approach makes it possible to solve the second order Boltzmann equation explicitly, with the spectral y distortion and the momentum independent second order temperature perturbation, while generation of μ distortion cannot be explained even at second order in this framework. We also extend our method to higher order Boltzmann equations systematically and find new type spectral distortions, assuming that the collision term is linear in the photon distribution functions, namely, in the Thomson scattering limit. As an example, we concretely construct solutions tomore » the cubic order Boltzmann equation and show that the equations are closed with additional three parameters composed of a cubic order temperature perturbation and two cubic order spectral distortions. The linear Sunyaev-Zel'dovich effect whose momentum dependence is different from the usual y distortion is also discussed in the presence of the next leading order Kompaneets terms, and we show that higher order spectral distortions are also generated as a result of the diffusion process in a framework of higher order Boltzmann equations. The method may be applicable to a wider class of problems and has potential to give a general prescription to non-equilibrium physics.« less

Quantum geometry of resurgent perturbative/nonperturbative relations

NASA Astrophysics Data System (ADS)

Basar, Gökçe; Dunne, Gerald V.; Ünsal, Mithat

2017-05-01

For a wide variety of quantum potentials, including the textbook `instanton' examples of the periodic cosine and symmetric double-well potentials, the perturbative data coming from fluctuations about the vacuum saddle encodes all non-perturbative data in all higher non-perturbative sectors. Here we unify these examples in geometric terms, arguing that the all-orders quantum action determines the all-orders quantum dual action for quantum spectral problems associated with a classical genus one elliptic curve. Furthermore, for a special class of genus one potentials this relation is particularly simple: this class includes the cubic oscillator, symmetric double-well, symmetric degenerate triple-well, and periodic cosine potential. These are related to the Chebyshev potentials, which are in turn related to certain \\mathcal{N} = 2 supersymmetric quantum field theories, to mirror maps for hypersurfaces in projective spaces, and also to topological c = 3 Landau-Ginzburg models and `special geometry'. These systems inherit a natural modular structure corresponding to Ramanujan's theory of elliptic functions in alternative bases, which is especially important for the quantization. Insights from supersymmetric quantum field theory suggest similar structures for more complicated potentials, corresponding to higher genus. Our approach is very elementary, using basic classical geometry combined with all-orders WKB.

Ghost-Free Theory with Third-Order Time Derivatives

NASA Astrophysics Data System (ADS)

Motohashi, Hayato; Suyama, Teruaki; Yamaguchi, Masahide

2018-06-01

As the first step to extend our understanding of higher-derivative theories, within the framework of analytic mechanics of point particles, we construct a ghost-free theory involving third-order time derivatives in Lagrangian. While eliminating linear momentum terms in the Hamiltonian is necessary and sufficient to kill the ghosts associated with higher derivatives for Lagrangian with at most second-order derivatives, we find that this is necessary but not sufficient for the Lagrangian with higher than second-order derivatives. We clarify a set of ghost-free conditions under which we show that the Hamiltonian is bounded, and that equations of motion are reducible into a second-order system.

A three-dimensional parabolic equation model of sound propagation using higher-order operator splitting and Padé approximants.

PubMed

Lin, Ying-Tsong; Collis, Jon M; Duda, Timothy F

2012-11-01

An alternating direction implicit (ADI) three-dimensional fluid parabolic equation solution method with enhanced accuracy is presented. The method uses a square-root Helmholtz operator splitting algorithm that retains cross-multiplied operator terms that have been previously neglected. With these higher-order cross terms, the valid angular range of the parabolic equation solution is improved. The method is tested for accuracy against an image solution in an idealized wedge problem. Computational efficiency improvements resulting from the ADI discretization are also discussed.

Oscillations and chaos in neural networks: an exactly solvable model.

PubMed Central

Wang, L P; Pichler, E E; Ross, J

1990-01-01

We consider a randomly diluted higher-order network with noise, consisting of McCulloch-Pitts neurons that interact by Hebbian-type connections. For this model, exact dynamical equations are derived and solved for both parallel and random sequential updating algorithms. For parallel dynamics, we find a rich spectrum of different behaviors including static retrieving and oscillatory and chaotic phenomena in different parts of the parameter space. The bifurcation parameters include first- and second-order neuronal interaction coefficients and a rescaled noise level, which represents the combined effects of the random synaptic dilution, interference between stored patterns, and additional background noise. We show that a marked difference in terms of the occurrence of oscillations or chaos exists between neural networks with parallel and random sequential dynamics. Images PMID:2251287

Quantum search algorithms on a regular lattice

NASA Astrophysics Data System (ADS)

Hein, Birgit; Tanner, Gregor

2010-07-01

Quantum algorithms for searching for one or more marked items on a d-dimensional lattice provide an extension of Grover’s search algorithm including a spatial component. We demonstrate that these lattice search algorithms can be viewed in terms of the level dynamics near an avoided crossing of a one-parameter family of quantum random walks. We give approximations for both the level splitting at the avoided crossing and the effectively two-dimensional subspace of the full Hilbert space spanning the level crossing. This makes it possible to give the leading order behavior for the search time and the localization probability in the limit of large lattice size including the leading order coefficients. For d=2 and d=3, these coefficients are calculated explicitly. Closed form expressions are given for higher dimensions.

Revealing cancer subtypes with higher-order correlations applied to imaging and omics data.

PubMed

Graim, Kiley; Liu, Tiffany Ting; Achrol, Achal S; Paull, Evan O; Newton, Yulia; Chang, Steven D; Harsh, Griffith R; Cordero, Sergio P; Rubin, Daniel L; Stuart, Joshua M

2017-03-31

Patient stratification to identify subtypes with different disease manifestations, severity, and expected survival time is a critical task in cancer diagnosis and treatment. While stratification approaches using various biomarkers (including high-throughput gene expression measurements) for patient-to-patient comparisons have been successful in elucidating previously unseen subtypes, there remains an untapped potential of incorporating various genotypic and phenotypic data to discover novel or improved groupings. Here, we present HOCUS, a unified analytical framework for patient stratification that uses a community detection technique to extract subtypes out of sparse patient measurements. HOCUS constructs a patient-to-patient network from similarities in the data and iteratively groups and reconstructs the network into higher order clusters. We investigate the merits of using higher-order correlations to cluster samples of cancer patients in terms of their associations with survival outcomes. In an initial test of the method, the approach identifies cancer subtypes in mutation data of glioblastoma, ovarian, breast, prostate, and bladder cancers. In several cases, HOCUS provides an improvement over using the molecular features directly to compare samples. Application of HOCUS to glioblastoma images reveals a size and location classification of tumors that improves over human expert-based stratification. Subtypes based on higher order features can reveal comparable or distinct groupings. The distinct solutions can provide biologically- and treatment-relevant solutions that are just as significant as solutions based on the original data.

Many-body dispersion interactions from the exchange-hole dipole moment model

NASA Astrophysics Data System (ADS)

Otero-de-la-Roza, A.; Johnson, Erin R.

2013-02-01

In this article, we present the extension of the exchange-hole dipole moment model (XDM) of dispersion interactions to the calculation of two-body and three-body dispersion energy terms to any order, 2l-pole oscillator strengths, and polarizabilities. By using the newly-formulated coefficients, we study the relative importance of the higher-order two-body and the leading non-additive three-body (triple-dipole) interactions in gas-phase as well as in condensed systems. We show that the two-body terms up to R-10, but not the terms of higher-order, are essential in the correct description of the dispersion energy, while there are a number of difficulties related to the choice of the damping function, which precludes the use three-body triple-dipole contributions in XDM. We conclude that further study is required before the three-body term can be used in production XDM density-functional calculations and point out the salient problems regarding its use.

Vector critical points and generalized quasi-efficient solutions in nonsmooth multi-objective programming.

PubMed

Wang, Zhen; Li, Ru; Yu, Guolin

2017-01-01

In this work, several extended approximately invex vector-valued functions of higher order involving a generalized Jacobian are introduced, and some examples are presented to illustrate their existences. The notions of higher-order (weak) quasi-efficiency with respect to a function are proposed for a multi-objective programming. Under the introduced generalization of higher-order approximate invexities assumptions, we prove that the solutions of generalized vector variational-like inequalities in terms of the generalized Jacobian are the generalized quasi-efficient solutions of nonsmooth multi-objective programming problems. Moreover, the equivalent conditions are presented, namely, a vector critical point is a weakly quasi-efficient solution of higher order with respect to a function.

Generalized Gödel universes in higher dimensions and pure Lovelock gravity

NASA Astrophysics Data System (ADS)

Dadhich, Naresh; Molina, Alfred; Pons, Josep M.

2017-10-01

The Gödel universe is a homogeneous rotating dust with negative Λ which is a direct product of a three-dimensional pure rotation metric with a line. We would generalize it to higher dimensions for Einstein and pure Lovelock gravity with only one N th-order term. For higher-dimensional generalization, we have to include more rotations in the metric, and hence we shall begin with the corresponding pure rotation odd (d =2 n +1 )-dimensional metric involving n rotations, which eventually can be extended by a direct product with a line or a space of constant curvature for yielding a higher-dimensional Gödel universe. The considerations of n rotations and also of constant curvature spaces is a new line of generalization and is being considered for the first time.

Towards construction of ghost-free higher derivative gravity from bigravity

NASA Astrophysics Data System (ADS)

Akagi, Satoshi

2018-06-01

In this paper, the ghost-freeness of the higher derivative theory proposed by Hassan et al. in [Universe 1, 92 (2015), 10.3390/universe1020092] is investigated. Hassan et al. believed the ghost-freeness of the higher derivative theory based on the analysis in the linear approximation. However, in order to obtain the complete correspondence, we have to analyze the model without any approximations. In this paper, we analyze the two-scalar model proposed in [Universe 1, 92 (2015), 10.3390/universe1020092] with arbitrary nonderivative interaction terms. In any order with respect to perturbative parameters, we prove that we can eliminate the ghost for the model with any nonderivative interaction terms.

Modulational instability of beat waves in a transversely magnetized plasma: Ion effects

NASA Astrophysics Data System (ADS)

Ferdous, T.; Amin, M. R.; Salimullah, M.

1996-05-01

The effect of ion dynamics on the modulational instability of the electrostatic beat wave at the difference frequency of two incident laser beams in a hot, collisionless, and transversely magnetized plasma has been studied theoretically. The full Vlasov equation in terms of gyrokinetic variables is employed to obtain the nonlinear response of ions and electrons. It is found that the growth rate of modulational instability is about two orders higher when ion motions are included.

The Adler D-function for N = 1 SQCD regularized by higher covariant derivatives in the three-loop approximation

NASA Astrophysics Data System (ADS)

Kataev, A. L.; Kazantsev, A. E.; Stepanyantz, K. V.

2018-01-01

We calculate the Adler D-function for N = 1 SQCD in the three-loop approximation using the higher covariant derivative regularization and the NSVZ-like subtraction scheme. The recently formulated all-order relation between the Adler function and the anomalous dimension of the matter superfields defined in terms of the bare coupling constant is first considered and generalized to the case of an arbitrary representation for the chiral matter superfields. The correctness of this all-order relation is explicitly verified at the three-loop level. The special renormalization scheme in which this all-order relation remains valid for the D-function and the anomalous dimension defined in terms of the renormalized coupling constant is constructed in the case of using the higher derivative regularization. The analytic expression for the Adler function for N = 1 SQCD is found in this scheme to the order O (αs2). The problem of scheme-dependence of the D-function and the NSVZ-like equation is briefly discussed.

A scheme to calculate higher-order homogenization as applied to micro-acoustic boundary value problems

NASA Astrophysics Data System (ADS)

Vagh, Hardik A.; Baghai-Wadji, Alireza

2008-12-01

Current technological challenges in materials science and high-tech device industry require the solution of boundary value problems (BVPs) involving regions of various scales, e.g. multiple thin layers, fibre-reinforced composites, and nano/micro pores. In most cases straightforward application of standard variational techniques to BVPs of practical relevance necessarily leads to unsatisfactorily ill-conditioned analytical and/or numerical results. To remedy the computational challenges associated with sub-sectional heterogeneities various sophisticated homogenization techniques need to be employed. Homogenization refers to the systematic process of smoothing out the sub-structural heterogeneities, leading to the determination of effective constitutive coefficients. Ordinarily, homogenization involves a sophisticated averaging and asymptotic order analysis to obtain solutions. In the majority of the cases only zero-order terms are constructed due to the complexity of the processes involved. In this paper we propose a constructive scheme for obtaining homogenized solutions involving higher order terms, and thus, guaranteeing higher accuracy and greater robustness of the numerical results. We present

Hamiltonian modelling of relative motion.

PubMed

Kasdin, N Jeremy; Gurfil, Pini

2004-05-01

This paper presents a Hamiltonian approach to modelling relative spacecraft motion based on derivation of canonical coordinates for the relative state-space dynamics. The Hamiltonian formulation facilitates the modelling of high-order terms and orbital perturbations while allowing us to obtain closed-form solutions to the relative motion problem. First, the Hamiltonian is partitioned into a linear term and a high-order term. The Hamilton-Jacobi equations are solved for the linear part by separation, and new constants for the relative motions are obtained, they are called epicyclic elements. The influence of higher order terms and perturbations, such as the oblateness of the Earth, are incorporated into the analysis by a variation of parameters procedure. Closed-form solutions for J(2-) and J(4-)invariant orbits and for periodic high-order unperturbed relative motion, in terms of the relative motion elements only, are obtained.

Perianal Dermatitis, Its Incidence, and Patterns of Topical Therapies in a Level IV Neonatal Intensive Care Unit.

PubMed

Malik, Anuj; Witsberger, Emily; Cottrell, Lesley; Kiefer, Autumn; Yossuck, Panitan

2018-04-01

 To define the incidence of perianal dermatitis (PD) and determine the usage pattern and cost efficacy of diaper products among neonates admitted to a level IV neonatal intensive care unit (NICU) including those with a diagnosis of neonatal abstinence syndrome (NAS).  A retrospective cohort study to evaluate neonates with PD based on number of orders for Aquaphor, Bagbalm, Desitin, Flanders, or Nystatin. Various demographic and clinical parameters were recorded. Usage patterns of these five products were analyzed, and their costs estimated. Subgroup analysis was performed among infants with NAS.  Of 1,241 admissions, 56.2% had at least one diaper product ordered during their NICU stay, while 52.6% had multiple products ordered. Only 23.0% of all neonates had appropriate documentation of PD. The most common product ordered first was Aquaphor (64.3%), followed by Desitin (19.2%). Note that 86% term NAS infants had PD compared with 28% term non-NAS infants. The estimated product cost was $14,139 over 2 years, averaging $20 per patient.  Over half of NICU neonates were exposed to one or more diaper products, usually without documented PD diagnosis. Term NAS infants had three times higher incidence of PD than term non-NAS infants. The cost of diaper product use was significant, and possibly underestimated due to lack of documentation. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Obtaining tight bounds on higher-order interferences with a 5-path interferometer

NASA Astrophysics Data System (ADS)

Kauten, Thomas; Keil, Robert; Kaufmann, Thomas; Pressl, Benedikt; Brukner, Časlav; Weihs, Gregor

2017-03-01

Within the established theoretical framework of quantum mechanics, interference always occurs between pairs of paths through an interferometer. Higher order interferences with multiple constituents are excluded by Born’s rule and can only exist in generalized probabilistic theories. Thus, high-precision experiments searching for such higher order interferences are a powerful method to distinguish between quantum mechanics and more general theories. Here, we perform such a test in an optical multi-path interferometer, which avoids crucial systematic errors, has access to the entire phase space and is more stable than previous experiments. Our results are in accordance with quantum mechanics and rule out the existence of higher order interference terms in optical interferometry to an extent that is more than four orders of magnitude smaller than the expected pairwise interference, refining previous bounds by two orders of magnitude.

A distinguishing gravitational property for gravitational equation in higher dimensions

NASA Astrophysics Data System (ADS)

Dadhich, Naresh

2016-03-01

It is well known that Einstein gravity is kinematic (meaning that there is no non-trivial vacuum solution; i.e. the Riemann tensor vanishes whenever the Ricci tensor does so) in 3 dimension because the Riemann tensor is entirely given in terms of the Ricci tensor. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one Nth order term in the action) gravity for which the Nth order Lovelock-Riemann tensor is indeed given in terms of the corresponding Ricci tensor for all odd, d=2N+1, dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good distinguishing and guiding criterion for the gravitational equation in higher dimensions.

Non-equilibrium many-body influence on mode-locked Vertical External-cavity Surface-emitting Lasers

NASA Astrophysics Data System (ADS)

Kilen, Isak Ragnvald

Vertical external-cavity surface-emitting lasers are ideal testbeds for studying the influence of the non-equilibrium many-body dynamics on mode locking. As we will show in this thesis, ultra short pulse generation involves a marked departure from Fermi carrier distributions assumed in prior theoretical studies. A quantitative model of the mode locking dynamics is presented, where the semiconductor Bloch equations with Maxwell's equation are coupled, in order to study the influences of quantum well carrier scattering on mode locking dynamics. This is the first work where the full model is solved without adiabatically eliminating the microscopic polarizations. In many instances we find that higher order correlation contributions (e.g. polarization dephasing, carrier scattering, and screening) can be represented by rate models, with the effective rates extracted at the level of second Born-Markov approximations. In other circumstances, such as continuous wave multi-wavelength lasing, we are forced to fully include these higher correlation terms. In this thesis we identify the key contributors that control mode locking dynamics, the stability of single pulse mode-locking, and the influence of higher order correlation in sustaining multi-wavelength continuous wave operation.

Quintessential quartic quasi-topological quartet

NASA Astrophysics Data System (ADS)

Ahmed, Jamil; Hennigar, Robie A.; Mann, Robert B.; Mir, Mozhgan

2017-05-01

We construct the quartic version of generalized quasi-topological gravity, which was recently constructed to cubic order in arXiv:1703.01631. This class of theories includes Lovelock gravity and a known form of quartic quasi-topological gravity as special cases and possess a number of remarkable properties: (i) In vacuum, or in the presence of suitable matter, there is a single independent field equation which is a total derivative. (ii) At the linearized level, the equations of motion on a maximally symmetric background are second order, coinciding with the linearized Einstein equations up to a redefinition of Newton's constant. Therefore, these theories propagate only the massless, transverse graviton on a maximally symmetric background. (iii) While the Lovelock and quasi-topological terms are trivial in four dimensions, there exist four new generalized quasi-topological terms (the quartet) that are nontrivial, leading to interesting higher curvature theories in d ≥ 4 dimensions that appear well suited for holographic study. We construct four dimensional black hole solutions to the theory and study their properties. A study of black brane solutions in arbitrary dimensions reveals that these solutions are modified from the `universal' properties they possess in other higher curvature theories, which may lead to interesting consequences for the dual CFTs.

Noncommutative geometry inspired Einstein–Gauss–Bonnet black holes

NASA Astrophysics Data System (ADS)

Ghosh, Sushant G.

2018-04-01

Low energy limits of a string theory suggests that the gravity action should include quadratic and higher-order curvature terms, in the form of dimensionally continued Gauss–Bonnet densities. Einstein–Gauss–Bonnet is a natural extension of the general relativity to higher dimensions in which the first and second-order terms correspond, respectively, to general relativity and Einstein–Gauss–Bonnet gravity. We obtain five-dimensional (5D) black hole solutions, inspired by a noncommutative geometry, with a static spherically symmetric, Gaussian mass distribution as a source both in the general relativity and Einstein–Gauss–Bonnet gravity cases, and we also analyzes their thermodynamical properties. Owing the noncommutative corrected black hole, the thermodynamic quantities have also been modified, and phase transition is shown to be achievable. The phase transitions for the thermodynamic stability, in both the theories, are characterized by a discontinuity in the specific heat at r_+=rC , with the stable (unstable) branch for r < (>) rC . The metric of the noncommutative inspired black holes smoothly goes over to the Boulware–Deser solution at large distance. The paper has been appended with a calculation of black hole mass using holographic renormalization.

Assessment of higher order structure comparability in therapeutic proteins using nuclear magnetic resonance spectroscopy.

PubMed

Amezcua, Carlos A; Szabo, Christina M

2013-06-01

In this work, we applied nuclear magnetic resonance (NMR) spectroscopy to rapidly assess higher order structure (HOS) comparability in protein samples. Using a variation of the NMR fingerprinting approach described by Panjwani et al. [2010. J Pharm Sci 99(8):3334-3342], three nonglycosylated proteins spanning a molecular weight range of 6.5-67 kDa were analyzed. A simple statistical method termed easy comparability of HOS by NMR (ECHOS-NMR) was developed. In this method, HOS similarity between two samples is measured via the correlation coefficient derived from linear regression analysis of binned NMR spectra. Applications of this method include HOS comparability assessment during new product development, manufacturing process changes, supplier changes, next-generation products, and the development of biosimilars to name just a few. We foresee ECHOS-NMR becoming a routine technique applied to comparability exercises used to complement data from other analytical techniques. Copyright © 2013 Wiley Periodicals, Inc.

Proofreading of DNA polymerase: a new kinetic model with higher-order terminal effects

NASA Astrophysics Data System (ADS)

Song, Yong-Shun; Shu, Yao-Gen; Zhou, Xin; Ou-Yang, Zhong-Can; Li, Ming

2017-01-01

The fidelity of DNA replication by DNA polymerase (DNAP) has long been an important issue in biology. While numerous experiments have revealed details of the molecular structure and working mechanism of DNAP which consists of both a polymerase site and an exonuclease (proofreading) site, there were quite a few theoretical studies on the fidelity issue. The first model which explicitly considered both sites was proposed in the 1970s and the basic idea was widely accepted by later models. However, all these models did not systematically investigate the dominant factor on DNAP fidelity, i.e. the higher-order terminal effects through which the polymerization pathway and the proofreading pathway coordinate to achieve high fidelity. In this paper, we propose a new and comprehensive kinetic model of DNAP based on some recent experimental observations, which includes previous models as special cases. We present a rigorous and unified treatment of the corresponding steady-state kinetic equations of any-order terminal effects, and derive analytical expressions for fidelity in terms of kinetic parameters under bio-relevant conditions. These expressions offer new insights on how the higher-order terminal effects contribute substantially to the fidelity in an order-by-order way, and also show that the polymerization-and-proofreading mechanism is dominated only by very few key parameters. We then apply these results to calculate the fidelity of some real DNAPs, which are in good agreements with previous intuitive estimates given by experimentalists.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Okumura, Teppei; Seljak, Uroš; McDonald, Patrick

Measurement of redshift-space distortions (RSD) offers an attractive method to directly probe the cosmic growth history of density perturbations. A distribution function approach where RSD can be written as a sum over density weighted velocity moment correlators has recently been developed. In this paper we use results of N-body simulations to investigate the individual contributions and convergence of this expansion for dark matter. If the series is expanded as a function of powers of μ, cosine of the angle between the Fourier mode and line of sight, then there are a finite number of terms contributing at each order. Wemore » present these terms and investigate their contribution to the total as a function of wavevector k. For μ{sup 2} the correlation between density and momentum dominates on large scales. Higher order corrections, which act as a Finger-of-God (FoG) term, contribute 1% at k ∼ 0.015hMpc{sup −1}, 10% at k ∼ 0.05hMpc{sup −1} at z = 0, while for k > 0.15hMpc{sup −1} they dominate and make the total negative. These higher order terms are dominated by density-energy density correlations which contributes negatively to the power, while the contribution from vorticity part of momentum density auto-correlation adds to the total power, but is an order of magnitude lower. For μ{sup 4} term the dominant term on large scales is the scalar part of momentum density auto-correlation, while higher order terms dominate for k > 0.15hMpc{sup −1}. For μ{sup 6} and μ{sup 8} we find it has very little power for k < 0.15hMpc{sup −1}, shooting up by 2–3 orders of magnitude between k < 0.15hMpc{sup −1} and k < 0.4hMpc{sup −1}. We also compare the expansion to the full 2-d P{sup ss}(k,μ), as well as to the monopole, quadrupole, and hexadecapole integrals of P{sup ss}(k,μ). For these statistics an infinite number of terms contribute and we find that the expansion achieves percent level accuracy for kμ < 0.15hMpc{sup −1} at 6-th order, but breaks down on smaller scales because the series is no longer perturbative. We explore resummation of the terms into FoG kernels, which extend the convergence up to a factor of 2 in scale. We find that the FoG kernels are approximately Lorentzian with velocity dispersions around 600 km/s at z = 0.« less

Higher Order, Hybrid BEM/FEM Methods Applied to Antenna Modeling

NASA Technical Reports Server (NTRS)

Fink, P. W.; Wilton, D. R.; Dobbins, J. A.

2002-01-01

In this presentation, the authors address topics relevant to higher order modeling using hybrid BEM/FEM formulations. The first of these is the limitation on convergence rates imposed by geometric modeling errors in the analysis of scattering by a dielectric sphere. The second topic is the application of an Incomplete LU Threshold (ILUT) preconditioner to solve the linear system resulting from the BEM/FEM formulation. The final tOpic is the application of the higher order BEM/FEM formulation to antenna modeling problems. The authors have previously presented work on the benefits of higher order modeling. To achieve these benefits, special attention is required in the integration of singular and near-singular terms arising in the surface integral equation. Several methods for handling these terms have been presented. It is also well known that achieving he high rates of convergence afforded by higher order bases may als'o require the employment of higher order geometry models. A number of publications have described the use of quadratic elements to model curved surfaces. The authors have shown in an EFIE formulation, applied to scattering by a PEC .sphere, that quadratic order elements may be insufficient to prevent the domination of modeling errors. In fact, on a PEC sphere with radius r = 0.58 Lambda(sub 0), a quartic order geometry representation was required to obtain a convergence benefi.t from quadratic bases when compared to the convergence rate achieved with linear bases. Initial trials indicate that, for a dielectric sphere of the same radius, - requirements on the geometry model are not as severe as for the PEC sphere. The authors will present convergence results for higher order bases as a function of the geometry model order in the hybrid BEM/FEM formulation applied to dielectric spheres. It is well known that the system matrix resulting from the hybrid BEM/FEM formulation is ill -conditioned. For many real applications, a good preconditioner is required to obtain usable convergence from an iterative solver. The authors have examined the use of an Incomplete LU Threshold (ILUT) preconditioner . to solver linear systems stemming from higher order BEM/FEM formulations in 2D scattering problems. Although the resulting preconditioner provided aD excellent approximation to the system inverse, its size in terms of non-zero entries represented only a modest improvement when compared with the fill-in associated with a sparse direct solver. Furthermore, the fill-in of the preconditioner could not be substantially reduced without the occurrence of instabilities. In addition to the results for these 2D problems, the authors will present iterative solution data from the application of the ILUT preconditioner to 3D problems.

Cost-effective accurate coarse-grid method for highly convective multidimensional unsteady flows

NASA Technical Reports Server (NTRS)

Leonard, B. P.; Niknafs, H. S.

1991-01-01

A fundamentally multidimensional convection scheme is described based on vector transient interpolation modeling rewritten in conservative control-volume form. Vector third-order upwinding is used as the basis of the algorithm; this automatically introduces important cross-difference terms that are absent from schemes using component-wise one-dimensional formulas. Third-order phase accuracy is good; this is important for coarse-grid large-eddy or full simulation. Potential overshoots or undershoots are avoided by using a recently developed universal limiter. Higher order accuracy is obtained locally, where needed, by the cost-effective strategy of adaptive stencil expansion in a direction normal to each control-volume face; this is controlled by monitoring the absolute normal gradient and curvature across the face. Higher (than third) order cross-terms do not appear to be needed. Since the wider stencil is used only in isolated narrow regions (near discontinuities), extremely high (in this case, seventh) order accuracy can be achieved for little more than the cost of a globally third-order scheme.

Stopping relativistic Xe, Ho, Au, and U nuclei in nuclear emulsions

NASA Technical Reports Server (NTRS)

Waddington, C. J.; Fixsen, D. J.; Freier, P. S.

1985-01-01

Nuclei of Xe-54, Ho-67, Au-79 and U-92 accelerated at the Bevalac to energies between 1200 and 900 MeV/n were stopped in nuclear emulsions. The observed residual ranges were compared with those calculated from various models of energy loss and shown to be most consistent with a calculation that includes those higher order correction terms proposed previously to describe the energy loss of highly changed particles, for which the first Born approximation is not valid.

Stopping relativistic Xe, Ho, Au and U nuclei in nuclear emulsions

NASA Technical Reports Server (NTRS)

Waddington, C. J.; Fixsen, D. J.; Freier, P. S.

1985-01-01

Nuclei of Xe-54, Ho-67, Au-79 and U-92 accelerated at the Bevalac to energies between 1200 and 900 MeV/n were stopped in nuclear emulsions. The observed residual ranges were compared with those calculated from various models of energy loss and shown to be most consistent with a calculation that includes those higher order correction terms proposed previously to describe the energy loss of highly charged particles, for which the first Born approximation is not valid.

The absence of intraband scattering in a consistent theory of Gilbert damping in pure metallic ferromagnets.

PubMed

Edwards, D M

2016-03-02

Damping of magnetization dynamics in a ferromagnetic metal, arising from spin-orbit coupling, is usually characterised by the Gilbert parameter α. Recent calculations of this quantity, using a formula due to Kambersky, find that it is infinite for a perfect crystal owing to an intraband scattering term which is of third order in the spin-orbit parameter ξ. This surprising result conflicts with recent work by Costa and Muniz who study damping numerically by direct calculation of the dynamical transverse susceptibility in the presence of spin-orbit coupling. We resolve this inconsistency by following the approach of Costa and Muniz for a slightly simplified model where it is possible to calculate α analytically. We show that to second order in ξ one retrieves the Kambersky result for α, but to higher order one does not obtain any divergent intraband terms. The present work goes beyond that of Costa and Muniz by pointing out the necessity of including the effect of long-range Coulomb interaction in calculating damping for large ξ. A direct derivation of the Kambersky formula is given which shows clearly the restriction of its validity to second order in ξ so that no intraband scattering terms appear. This restriction has an important effect on the damping over a substantial range of impurity content and temperature. The experimental situation is discussed.

Tensorial Calibration. 2. Second Order Tensorial Calibration.

DTIC Science & Technology

1987-10-12

index is repeated more than once only in one side of an equation, it implies a summation over the index valid range. 12 To avoid confusion of terms...and higher order tensor, the rank can be higher than the maximum dimensionality. 13 ,ON 6 LINEAR SECOND ORDER TENSORIAL CALIBRATION MODEL From...these equations are valid only if all the elements of the diagonal matrix B3 are non-zero because its inverse (-1) must be computed. This implies that M

The Ostrogradsky Prescription for BFV Formalism

NASA Astrophysics Data System (ADS)

Nirov, Khazret S.

Gauge-invariant systems of a general form with higher order time derivatives of gauge parameters are investigated within the framework of the BFV formalism. Higher order terms of the BRST charge and BRST-invariant Hamiltonian are obtained. It is shown that the identification rules for Lagrangian and Hamiltonian BRST ghost variables depend on the choice of the extension of constraints from the primary constraint surface.

Third-order dissipative hydrodynamics from the entropy principle

NASA Astrophysics Data System (ADS)

El, Andrej; Xu, Zhe; Greiner, Carsten

2010-06-01

We review the entropy based derivation of third-order hydrodynamic equations and compare their solutions in one-dimensional boost-invariant geometry with calculations by the partonic cascade BAMPS. We demonstrate that Grad's approximation, which underlies the derivation of both Israel-Stewart and third-order equations, describes the transverse spectra from BAMPS with high accuracy. At the same time solutions of third-order equations are much closer to BAMPS results than solutions of Israel-Stewart equations. Introducing a resummation scheme for all higher-oder corrections to one-dimensional hydrodynamic equation we demonstrate the importance of higher-order terms if the Knudsen number is large.

Time-dependent variational approach in terms of squeezed coherent states: Implication to semi-classical approximation

NASA Technical Reports Server (NTRS)

Tsue, Yasuhiko

1994-01-01

A general framework for time-dependent variational approach in terms of squeezed coherent states is constructed with the aim of describing quantal systems by means of classical mechanics including higher order quantal effects with the aid of canonicity conditions developed in the time-dependent Hartree-Fock theory. The Maslov phase occurring in a semi-classical quantization rule is investigated in this framework. In the limit of a semi-classical approximation in this approach, it is definitely shown that the Maslov phase has a geometric nature analogous to the Berry phase. It is also indicated that this squeezed coherent state approach is a possible way to go beyond the usual WKB approximation.

Systematic review of the neural basis of social cognition in patients with mood disorders.

PubMed

Cusi, Andrée M; Nazarov, Anthony; Holshausen, Katherine; Macqueen, Glenda M; McKinnon, Margaret C

2012-05-01

This review integrates neuroimaging studies of 2 domains of social cognition--emotion comprehension and theory of mind (ToM)--in patients with major depressive disorder and bipolar disorder. The influence of key clinical and method variables on patterns of neural activation during social cognitive processing is also examined. Studies were identified using PsycINFO and PubMed (January 1967 to May 2011). The search terms were "fMRI," "emotion comprehension," "emotion perception," "affect comprehension," "affect perception," "facial expression," "prosody," "theory of mind," "mentalizing" and "empathy" in combination with "major depressive disorder," "bipolar disorder," "major depression," "unipolar depression," "clinical depression" and "mania." Taken together, neuroimaging studies of social cognition in patients with mood disorders reveal enhanced activation in limbic and emotion-related structures and attenuated activity within frontal regions associated with emotion regulation and higher cognitive functions. These results reveal an overall lack of inhibition by higher-order cognitive structures on limbic and emotion-related structures during social cognitive processing in patients with mood disorders. Critically, key variables, including illness burden, symptom severity, comorbidity, medication status and cognitive load may moderate this pattern of neural activation. Studies that did not include control tasks or a comparator group were included in this review. Further work is needed to examine the contribution of key moderator variables and to further elucidate the neural networks underlying altered social cognition in patients with mood disorders. The neural networks under lying higher-order social cognitive processes, including empathy, remain unexplored in patients with mood disorders.

Higher-order accurate space-time schemes for computational astrophysics—Part I: finite volume methods

NASA Astrophysics Data System (ADS)

Balsara, Dinshaw S.

2017-12-01

As computational astrophysics comes under pressure to become a precision science, there is an increasing need to move to high accuracy schemes for computational astrophysics. The algorithmic needs of computational astrophysics are indeed very special. The methods need to be robust and preserve the positivity of density and pressure. Relativistic flows should remain sub-luminal. These requirements place additional pressures on a computational astrophysics code, which are usually not felt by a traditional fluid dynamics code. Hence the need for a specialized review. The focus here is on weighted essentially non-oscillatory (WENO) schemes, discontinuous Galerkin (DG) schemes and PNPM schemes. WENO schemes are higher order extensions of traditional second order finite volume schemes. At third order, they are most similar to piecewise parabolic method schemes, which are also included. DG schemes evolve all the moments of the solution, with the result that they are more accurate than WENO schemes. PNPM schemes occupy a compromise position between WENO and DG schemes. They evolve an Nth order spatial polynomial, while reconstructing higher order terms up to Mth order. As a result, the timestep can be larger. Time-dependent astrophysical codes need to be accurate in space and time with the result that the spatial and temporal accuracies must be matched. This is realized with the help of strong stability preserving Runge-Kutta schemes and ADER (Arbitrary DERivative in space and time) schemes, both of which are also described. The emphasis of this review is on computer-implementable ideas, not necessarily on the underlying theory.

Automorphic properties of low energy string amplitudes in various dimensions

NASA Astrophysics Data System (ADS)

Green, Michael B.; Russo, Jorge G.; Vanhove, Pierre

2010-04-01

This paper explores the moduli-dependent coefficients of higher-derivative interactions that appear in the low-energy expansion of the four-supergraviton amplitude of maximally supersymmetric string theory compactified on a d torus. These automorphic functions are determined for terms up to order ∂6R4 and various values of d by imposing a variety of consistency conditions. They satisfy Laplace eigenvalue equations with or without source terms, whose solutions are given in terms of Eisenstein series, or more general automorphic functions, for certain parabolic subgroups of the relevant U-duality groups. The ultraviolet divergences of the corresponding supergravity field theory limits are encoded in various logarithms, although the string theory expressions are finite. This analysis includes intriguing representations of SL(d) and SO(d,d) Eisenstein series in terms of toroidally compactified one and two-loop string and supergravity amplitudes.

Curvature and gravity actions for matrix models: II. The case of general Poisson structures

NASA Astrophysics Data System (ADS)

Blaschke, Daniel N.; Steinacker, Harold

2010-12-01

We study the geometrical meaning of higher order terms in matrix models of Yang-Mills type in the semi-classical limit, generalizing recent results (Blaschke and Steinacker 2010 Class. Quantum Grav. 27 165010 (arXiv:1003.4132)) to the case of four-dimensional spacetime geometries with general Poisson structure. Such terms are expected to arise e.g. upon quantization of the IKKT-type models. We identify terms which depend only on the intrinsic geometry and curvature, including modified versions of the Einstein-Hilbert action as well as terms which depend on the extrinsic curvature. Furthermore, a mechanism is found which implies that the effective metric G on the spacetime brane {\\cal M}\\subset \\mathds{R}^D 'almost' coincides with the induced metric g. Deviations from G = g are suppressed, and characterized by the would-be U(1) gauge field.

Quantum geometry of resurgent perturbative/nonperturbative relations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Basar, Gokce; Dunne, Gerald V.; Unsal, Mithat

For a wide variety of quantum potentials, including the textbook ‘instanton’ examples of the periodic cosine and symmetric double-well potentials, the perturbative data coming from fluctuations about the vacuum saddle encodes all non-perturbative data in all higher non-perturbative sectors. Here we unify these examples in geometric terms, arguing that the all-orders quantum action determines the all-orders quantum dual action for quantum spectral problems associated with a classical genus one elliptic curve. Furthermore, for a special class of genus one potentials this relation is particularly simple: this class includes the cubic oscillator, symmetric double-well, symmetric degenerate triple-well, and periodic cosine potential.more » These are related to the Chebyshev potentials, which are in turn related to certain N = 2 supersymmetric quantum field theories, to mirror maps for hypersurfaces in projective spaces, and also to topological c = 3 Landau-Ginzburg models and ‘special geometry’. These systems inherit a natural modular structure corresponding to Ramanujan’s theory of elliptic functions in alternative bases, which is especially important for the quantization. Insights from supersymmetric quantum field theory suggest similar structures for more complicated potentials, corresponding to higher genus. Lastly, our approach is very elementary, using basic classical geometry combined with all-orders WKB.« less

Quantum geometry of resurgent perturbative/nonperturbative relations

DOE PAGES

Basar, Gokce; Dunne, Gerald V.; Unsal, Mithat

2017-05-16

For a wide variety of quantum potentials, including the textbook ‘instanton’ examples of the periodic cosine and symmetric double-well potentials, the perturbative data coming from fluctuations about the vacuum saddle encodes all non-perturbative data in all higher non-perturbative sectors. Here we unify these examples in geometric terms, arguing that the all-orders quantum action determines the all-orders quantum dual action for quantum spectral problems associated with a classical genus one elliptic curve. Furthermore, for a special class of genus one potentials this relation is particularly simple: this class includes the cubic oscillator, symmetric double-well, symmetric degenerate triple-well, and periodic cosine potential.more » These are related to the Chebyshev potentials, which are in turn related to certain N = 2 supersymmetric quantum field theories, to mirror maps for hypersurfaces in projective spaces, and also to topological c = 3 Landau-Ginzburg models and ‘special geometry’. These systems inherit a natural modular structure corresponding to Ramanujan’s theory of elliptic functions in alternative bases, which is especially important for the quantization. Insights from supersymmetric quantum field theory suggest similar structures for more complicated potentials, corresponding to higher genus. Lastly, our approach is very elementary, using basic classical geometry combined with all-orders WKB.« less

Higher-order stochastic differential equations and the positive Wigner function

NASA Astrophysics Data System (ADS)

Drummond, P. D.

2017-12-01

General higher-order stochastic processes that correspond to any diffusion-type tensor of higher than second order are obtained. The relationship of multivariate higher-order stochastic differential equations with tensor decomposition theory and tensor rank is explained. Techniques for generating the requisite complex higher-order noise are proved to exist either using polar coordinates and γ distributions, or from products of Gaussian variates. This method is shown to allow the calculation of the dynamics of the Wigner function, after it is extended to a complex phase space. The results are illustrated physically through dynamical calculations of the positive Wigner distribution for three-mode parametric downconversion, widely used in quantum optics. The approach eliminates paradoxes arising from truncation of the higher derivative terms in Wigner function time evolution. Anomalous results of negative populations and vacuum scattering found in truncated Wigner quantum simulations in quantum optics and Bose-Einstein condensate dynamics are shown not to occur with this type of stochastic theory.

Improvements to the George/Castillo Boundary Layer Theory

NASA Astrophysics Data System (ADS)

Wosnik, Martin; George, William K.; Castillo, Luciano

2000-11-01

George and Castillo (1997)(George WK and Castillo L (1997) Appl.Mech.Rev.), 50, 12/1, 689-729. presented a new theory for Zero Pressure Gradient Turbulent Boundary Layers based on an application of Near-Asymptotics to scaling laws derived from equilibrium similarity to the Reynolds-averaged equations. The resulting overlap velocity profiles retained a dependence on local Reynolds number, the parameters for which had to satisfy the following constraint equation: ln \\varepsilon fracdγd ln δ^+ = fracdln [C_o/C_i] d ln δ^+ where γ is the power exponent, Co and Ci are the coefficients in inner and outer variables respectively. GC considered only the first term in an asymptotic expansion of the exact solution, but higher order terms can be considered with no increase in the number of unknowns. The improved theory is tested against new experimental Zero Pressure Gradient Turbulent Boundary Layer data of Smith (1994), Oesterlund (1999) and Johansson and Castillo (2000). For the friction law, the first order term is sufficient, but for Co and γ the higher order terms improve the fit to the velocity profiles significantly.

Reliable prediction of three-body intermolecular interactions using dispersion-corrected second-order Møller-Plesset perturbation theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Yuanhang; Beran, Gregory J. O., E-mail: gregory.beran@ucr.edu

2015-07-28

Three-body and higher intermolecular interactions can play an important role in molecular condensed phases. Recent benchmark calculations found problematic behavior for many widely used density functional approximations in treating 3-body intermolecular interactions. Here, we demonstrate that the combination of second-order Møller-Plesset (MP2) perturbation theory plus short-range damped Axilrod-Teller-Muto (ATM) dispersion accurately describes 3-body interactions with reasonable computational cost. The empirical damping function used in the ATM dispersion term compensates both for the absence of higher-order dispersion contributions beyond the triple-dipole ATM term and non-additive short-range exchange terms which arise in third-order perturbation theory and beyond. Empirical damping enables this simplemore » model to out-perform a non-expanded coupled Kohn-Sham dispersion correction for 3-body intermolecular dispersion. The MP2 plus ATM dispersion model approaches the accuracy of O(N{sup 6}) methods like MP2.5 or even spin-component-scaled coupled cluster models for 3-body intermolecular interactions with only O(N{sup 5}) computational cost.« less

Second-order closure models for supersonic turbulent flows

NASA Technical Reports Server (NTRS)

Speziale, Charles G.; Sarkar, Sutanu

1991-01-01

Recent work by the authors on the development of a second-order closure model for high-speed compressible flows is reviewed. This turbulence closure is based on the solution of modeled transport equations for the Favre-averaged Reynolds stress tensor and the solenoidal part of the turbulent dissipation rate. A new model for the compressible dissipation is used along with traditional gradient transport models for the Reynolds heat flux and mass flux terms. Consistent with simple asymptotic analyses, the deviatoric part of the remaining higher-order correlations in the Reynolds stress transport equation are modeled by a variable density extension of the newest incompressible models. The resulting second-order closure model is tested in a variety of compressible turbulent flows which include the decay of isotropic turbulence, homogeneous shear flow, the supersonic mixing layer, and the supersonic flat-plate turbulent boundary layer. Comparisons between the model predictions and the results of physical and numerical experiments are quite encouraging.

Second-order closure models for supersonic turbulent flows

NASA Technical Reports Server (NTRS)

Speziale, Charles G.; Sarkar, Sutanu

1991-01-01

Recent work on the development of a second-order closure model for high-speed compressible flows is reviewed. This turbulent closure is based on the solution of modeled transport equations for the Favre-averaged Reynolds stress tensor and the solenoidal part of the turbulent dissipation rate. A new model for the compressible dissipation is used along with traditional gradient transport models for the Reynolds heat flux and mass flux terms. Consistent with simple asymptotic analyses, the deviatoric part of the remaining higher-order correlations in the Reynolds stress transport equations are modeled by a variable density extension of the newest incompressible models. The resulting second-order closure model is tested in a variety of compressible turbulent flows which include the decay of isotropic turbulence, homogeneous shear flow, the supersonic mixing layer, and the supersonic flat-plate turbulent boundary layer. Comparisons between the model predictions and the results of physical and numerical experiments are quite encouraging.

Estimate of higher order ionospheric errors in GNSS positioning

NASA Astrophysics Data System (ADS)

Hoque, M. Mainul; Jakowski, N.

2008-10-01

Precise navigation and positioning using GPS/GLONASS/Galileo require the ionospheric propagation errors to be accurately determined and corrected for. Current dual-frequency method of ionospheric correction ignores higher order ionospheric errors such as the second and third order ionospheric terms in the refractive index formula and errors due to bending of the signal. The total electron content (TEC) is assumed to be same at two GPS frequencies. All these assumptions lead to erroneous estimations and corrections of the ionospheric errors. In this paper a rigorous treatment of these problems is presented. Different approximation formulas have been proposed to correct errors due to excess path length in addition to the free space path length, TEC difference at two GNSS frequencies, and third-order ionospheric term. The GPS dual-frequency residual range errors can be corrected within millimeter level accuracy using the proposed correction formulas.

Birth Order, Club Membership and Mass Media Exposure

ERIC Educational Resources Information Center

Tomeh, Aida K.

1976-01-01

Examines the relationship between birth order, club membership and mass media exposure for women college students in Lebanon. Findings show the total membership rate and mass media consumption are higher among last born girls than first born. Birth order differences are explained in terms of the differential socialization of children. (Author)

Higher order moments, structure functions and spectral ratios in near- and far-wakes of a wind turbine array

NASA Astrophysics Data System (ADS)

Ali, Naseem; Aseyev, A.; McCraney, J.; Vuppuluri, V.; Abbass, O.; Al Jubaree, T.; Melius, M.; Cal, R. B.

2014-11-01

Hot-wire measurements obtained in a 3 × 3 wind turbine array boundary layer are utilized to analyze higher order statistics which include skewness, kurtosis as well as the ratios of structure functions and spectra. The ratios consist of wall-normal to streamwise components for both quantities. The aim is to understand the degree of anisotropy in the flow for the near- and far-wakes of the flow field where profiles at one diameter and five diameters are considered, respectively. The skewness at top tip for both wakes show a negative skewness while below the turbine canopy, this terms are positive. The kurtosis shows a Gaussian behavior in the near-wake immediately at hub-height. In addition, the effect due to the passage of the rotor in tandem with the shear layer at the top tip renders relatively high differences in the fourth order moment. The second order structure function and spectral ratios are found to exhibit anisotropic behavior at the top and bottom-tips for the large scales. Mixed structure functions and co-spectra are also considered in the context of isotropy.

Vector breather-to-soliton transitions and nonlinear wave interactions induced by higher-order effects in an erbium-doped fiber

NASA Astrophysics Data System (ADS)

Sun, Wen-Rong; Wang, Lei; Xie, Xi-Yang

2018-06-01

Vector breather-to-soliton transitions for the higher-order nonlinear Schrödinger-Maxwell-Bloch (NLS-MB) system with sextic terms are investigated. The Lax pair and Darboux transformation (DT) of such system are constructed. With the DT, analytic vector breather solutions up to the second order are obtained. With appropriate choices of the spectra parameters, vector breather-to-soliton transitions happen. Interaction mechanisms of vector nonlinear waves (breather-soliton or soliton-soliton interactions) are displayed.

Mutual potential between two rigid bodies with arbitrary shapes and mass distributions

NASA Astrophysics Data System (ADS)

Hou, Xiyun; Scheeres, Daniel J.; Xin, Xiaosheng

2017-03-01

Formulae to compute the mutual potential, force, and torque between two rigid bodies are given. These formulae are expressed in Cartesian coordinates using inertia integrals. They are valid for rigid bodies with arbitrary shapes and mass distributions. By using recursive relations, these formulae can be easily implemented on computers. Comparisons with previous studies show their superiority in computation speed. Using the algorithm as a tool, the planar problem of two ellipsoids is studied. Generally, potential truncated at the second order is good enough for a qualitative description of the mutual dynamics. However, for ellipsoids with very large non-spherical terms, higher order terms of the potential should be considered, at the cost of a higher computational cost. Explicit formulae of the potential truncated to the fourth order are given.

A Long-Term Experiment to Investigate the Relationships between High School Students' Perceptions of Mobile Learning and Peer Interaction and Higher-Order Thinking Tendencies

ERIC Educational Resources Information Center

Hwang, Gwo-Jen; Lai, Chiu-Lin; Liang, Jyh-Chong; Chu, Hui-Chun; Tsai, Chin-Chung

2018-01-01

In this study, a one-year program was conducted to investigate the relationships between students' perceptions of mobile learning and their tendencies of peer interaction and higher-order thinking in issue-based mobile learning activities. To achieve the research objective, a survey consisting of eight scales, namely, usability, continuity,…

A Comparison of Mother-Tongue Curricula of Successful Countries in PISA and Turkey by Higher-Order Thinking Processes

ERIC Educational Resources Information Center

Cer, Erkan

2018-01-01

Purpose: The purpose of the current study is to reveal general qualities of the objectives in the mother-tongue curricula of Hong Kong and Shanghai-China, South Korea, Singapore, and Turkey in terms of higher-order thinking processes specified by PISA tests. Research Methods: In this study, the researcher used a qualitative research design.…

Impact and Implementation of Higher-Order Ionospheric Effects on Precise GNSS Applications

NASA Astrophysics Data System (ADS)

Hadas, T.; Krypiak-Gregorczyk, A.; Hernández-Pajares, M.; Kaplon, J.; Paziewski, J.; Wielgosz, P.; Garcia-Rigo, A.; Kazmierski, K.; Sosnica, K.; Kwasniak, D.; Sierny, J.; Bosy, J.; Pucilowski, M.; Szyszko, R.; Portasiak, K.; Olivares-Pulido, G.; Gulyaeva, T.; Orus-Perez, R.

2017-11-01

High precision Global Navigation Satellite Systems (GNSS) positioning and time transfer require correcting signal delays, in particular higher-order ionospheric (I2+) terms. We present a consolidated model to correct second- and third-order terms, geometric bending and differential STEC bending effects in GNSS data. The model has been implemented in an online service correcting observations from submitted RINEX files for I2+ effects. We performed GNSS data processing with and without including I2+ corrections, in order to investigate the impact of I2+ corrections on GNSS products. We selected three time periods representing different ionospheric conditions. We used GPS and GLONASS observations from a global network and two regional networks in Poland and Brazil. We estimated satellite orbits, satellite clock corrections, Earth rotation parameters, troposphere delays, horizontal gradients, and receiver positions using global GNSS solution, Real-Time Kinematic (RTK), and Precise Point Positioning (PPP) techniques. The satellite-related products captured most of the impact of I2+ corrections, with the magnitude up to 2 cm for clock corrections, 1 cm for the along- and cross-track orbit components, and below 5 mm for the radial component. The impact of I2+ on troposphere products turned out to be insignificant in general. I2+ corrections had limited influence on the performance of ambiguity resolution and the reliability of RTK positioning. Finally, we found that I2+ corrections caused a systematic shift in the coordinate domain that was time- and region-dependent and reached up to -11 mm for the north component of the Brazilian stations during the most active ionospheric conditions.

Theory of the magnetic susceptibility including zero-point spin fluctuations of itinerant nearly ferromagnetic compounds

NASA Astrophysics Data System (ADS)

Konno, Rikio; Hatayama, Nobukuni; Takahashi, Yoshinori

2018-05-01

We have investigated the temperature dependence of the magnetic susceptibility of itinerant nearly ferromagnetic compounds based on the spin fluctuation theory. It is based on the conservation of the local spin amplitude that consists of both the thermal and the zero-point components. The linear dependence of the zero-point spin fluctuation amplitude on the inverse of magnetic susceptibility is usually assumed. The purpose of our present study is to include its higher order terms and to see their effects on the magnetic susceptibility. For the thermal amplitude, it shows T2-linear temperature dependence at low temperatures.

A hierarchical generalization of the acoustic reciprocity theorem involving higher-order derivatives and interaction quantities.

PubMed

Lin, Ju; Li, Jie; Li, Xiaolei; Wang, Ning

2016-10-01

An acoustic reciprocity theorem is generalized, for a smoothly varying perturbed medium, to a hierarchy of reciprocity theorems including higher-order derivatives of acoustic fields. The standard reciprocity theorem is the first member of the hierarchy. It is shown that the conservation of higher-order interaction quantities is related closely to higher-order derivative distributions of perturbed media. Then integral reciprocity theorems are obtained by applying Gauss's divergence theorem, which give explicit integral representations connecting higher-order interactions and higher-order derivative distributions of perturbed media. Some possible applications to an inverse problem are also discussed.

Effect of second-order exchange in electron-hydrogen scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madison, D.H.; Bray, I.; McCarthy, I.

1990-05-07

The electron-hydrogen scattering problem has been a nemesis to theoretical atomic physicists due to the fact that even the most sophisticated of theoretical calculations, both perturbative and nonperturbative, do not agree with experiment. The current opinion is that the perturbative approach cannot be used for this problem since recent second-order calculations are not in agreement with the experimental data and higher-order calculations are deemed impractical. However, these second-order calculations neglected second-order exchange. We have now added exchange to the second-order calculation and have found that the primary source of disagreement between experiment and theory for intermediate energies is attributable notmore » to higher-order terms but to second-order exchange.« less

Optical and Biometric Characteristics of Anisomyopia in Human Adults

PubMed Central

Tian, Yibin; Tarrant, Janice; Wildsoet, Christine F.

2011-01-01

Purpose To investigate the role of higher order optical aberrations and thus retinal image degradation in the development of myopia, through the characterization of anisomyopia in human adults in terms of their optical and biometric characteristics. Methods The following data were collected from both eyes of fifteen young adult anisometropic myopes and sixteen isometropic myopes: subjective and objective refractive errors, corneal power and shape, monochromatic optical aberrations, anterior chamber depth, lens thickness, vitreous chamber depth, and best corrected visual acuity. Monochromatic aberrations were analyzed in terms of their higher order components, and further analyzed in terms of 31 optical quality metrics. Interocular differences for the two groups (anisomyopes vs. isomyopes) were compared and the relationship between measured ocular parameters and refractive errors also analyzed across all eyes. Results As expected, anisomyopes and isomyopes differed significantly in terms of interocular differences in vitreous chamber depth, axial length and refractive error. However, interocular differences in other optical properties showed no significant intergroup differences. Overall, higher myopia was associated with deeper anterior and vitreous chambers, higher astigmatism, more prolate corneas, and more positive spherical aberration. Other measured optical and biometric parameters were not significantly correlated with spherical refractive error, although some optical quality metrics and corneal astigmatism were significantly correlated with refractive astigmatism. Conclusions An optical cause for anisomyopia related to increased higher order aberrations is not supported by our data. Corneal shape changes and increased astigmatism in more myopic eyes may be a by-product of the increased anterior chamber growth in these eyes; likewise, the increased positive spherical aberration in more myopic eyes may be a product of myopic eye growth. PMID:21797915

A PVS Prover Strategy Package for Common Manipulations

NASA Technical Reports Server (NTRS)

DiVito, Ben L.

2002-01-01

Sequent manipulations for an interactive prover such as PVS can often be labor intensive. We describe an approach to tactic-based proving for improved interactive deduction in specialized domains. An experimental package of strategies (tactics) and support functions has been developed for PVS to reduce the tedium of arithmetic manipulation. Included are strategies aimed at algebraic simplification of real-valued expressions as well as term-access techniques applicable in arbitrary settings. The approach is general enough to serve in other mathematical domains and for provers other than PVS. This report presents the full set of arithmetic strategies and discusses how they are invoked within the prover. Included is a description of the extended expression notation for accessing terms as well as a substitution technique provided for higher-order strategies. Several sample proofs are displayed in full to show how the strategies might be used in practice.

Bs and Ds decay constants in three-flavor lattice QCD.

PubMed

Wingate, Matthew; Davies, Christine T H; Gray, Alan; Lepage, G Peter; Shigemitsu, Junko

2004-04-23

Capitalizing on recent advances in lattice QCD, we present a calculation of the leptonic decay constants f(B(s)) and f(D(s)) that includes effects of one strange sea quark and two light sea quarks via an improved staggered action. By shedding the quenched approximation and the associated lattice scale uncertainty, lattice QCD greatly increases its predictive power. Nonrelativistic QCD is used to simulate heavy quarks with masses between 1.5m(c) and m(b). We arrive at the following results: f(B(s))=260+/-7+/-26+/-8+/-5 and f(D(s))=290+/-20+/-29+/-29+/-6 MeV. The first quoted error is the statistical uncertainty, and the rest estimate the sizes of higher order terms neglected in this calculation. All of these uncertainties are systematically improvable by including another order in the weak coupling expansion, the nonrelativistic expansion, or the Symanzik improvement program.

Higher-order finite-difference formulation of periodic Orbital-free Density Functional Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Swarnava; Suryanarayana, Phanish, E-mail: phanish.suryanarayana@ce.gatech.edu

2016-02-15

We present a real-space formulation and higher-order finite-difference implementation of periodic Orbital-free Density Functional Theory (OF-DFT). Specifically, utilizing a local reformulation of the electrostatic and kernel terms, we develop a generalized framework for performing OF-DFT simulations with different variants of the electronic kinetic energy. In particular, we propose a self-consistent field (SCF) type fixed-point method for calculations involving linear-response kinetic energy functionals. In this framework, evaluation of both the electronic ground-state and forces on the nuclei are amenable to computations that scale linearly with the number of atoms. We develop a parallel implementation of this formulation using the finite-difference discretization.more » We demonstrate that higher-order finite-differences can achieve relatively large convergence rates with respect to mesh-size in both the energies and forces. Additionally, we establish that the fixed-point iteration converges rapidly, and that it can be further accelerated using extrapolation techniques like Anderson's mixing. We validate the accuracy of the results by comparing the energies and forces with plane-wave methods for selected examples, including the vacancy formation energy in Aluminum. Overall, the suitability of the proposed formulation for scalable high performance computing makes it an attractive choice for large-scale OF-DFT calculations consisting of thousands of atoms.« less

BRST Formalism for Systems with Higher Order Derivatives of Gauge Parameters

NASA Astrophysics Data System (ADS)

Nirov, Kh. S.

For a wide class of mechanical systems, invariant under gauge transformations with arbitrary higher order time derivatives of gauge parameters, the equivalence of Lagrangian and Hamiltonian BRST formalisms is proved. It is shown that the Ostrogradsky formalism establishes the natural rules to relate the BFV ghost canonical pairs with the ghosts and antighosts introduced by the Lagrangian approach. Explicit relation between corresponding gauge-fixing terms is obtained.

Development of a Higher Order Laminate Theory for Modeling Composites with Induced Strain Actuators

NASA Technical Reports Server (NTRS)

Chattopadhyay, Aditi; Seeley, Charles E.

1996-01-01

A refined higher order plate theory is developed to investigate the actuation mechanism of piezoelectric materials surface bonded or embedded in composite laminates. The current analysis uses a displacement field which accurately accounts for transverse shear stresses. Some higher order terms are identified by using the conditions that shear stresses vanish at all free surfaces. Therefore, all boundary conditions for displacements and stresses are satisfied in the present theory. The analysis is implemented using the finite element method which provides a convenient means to construct a numerical solution due to the discrete nature of the actuators. The higher order theory is computationally less expensive than a full three dimensional analysis. The theory is also shown to agree well with published experimental results. Numerical examples are presented for composite plates with thicknesses ranging from thin to very thick.

The QCD form factor of heavy quarks at NNLO

NASA Astrophysics Data System (ADS)

Gluza, J.; Mitov, A.; Moch, S.; Riemann, T.

2009-07-01

We present an analytical calculation of the two-loop QCD corrections to the electromagnetic form factor of heavy quarks. The two-loop contributions to the form factor are reduced to linear combinations of master integrals, which are computed through higher orders in the parameter of dimensional regularization epsilon = (4-D)/2. Our result includes all terms of order epsilon at two loops and extends the previous literature. We apply the exponentiation of the heavy-quark form factor to derive new improved three-loop expansions in the high-energy limit. We also discuss the implications for predictions of massive n-parton amplitudes based on massless results in the limit, where the quark mass is small compared to all kinematical invariants.

On the vanishing couplings in ADE affine Toda field theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saitoh, Y.; Shimada, T.

In this paper, the authors show that certain vanishing couplins in the ADE affine Toda field theories remain vanishing even after higher-order corrections are included. This is a requisite property for the Lagrangian formulation of the theory. The authors develop a new perturbative formulation and treat affine Toda field theories as a massless theory with exponential interaction terms. The authors shown that the nonrenormalization comes from the Dynkin automorphism of the Lie algebra associated with these theories. A charge balance conditions plays an important role in our scheme. The all-order nonrenormalization of vanishing couplings in [bar A][sub n] affine Todamore » field theory is also proved in a standard massive scheme.« less

A root-mean-square pressure fluctuations model for internal flow applications

NASA Technical Reports Server (NTRS)

Chen, Y. S.

1985-01-01

A transport equation for the root-mean-square pressure fluctuations of turbulent flow is derived from the time-dependent momentum equation for incompressible flow. Approximate modeling of this transport equation is included to relate terms with higher order correlations to the mean quantities of turbulent flow. Three empirical constants are introduced in the model. Two of the empirical constants are estimated from homogeneous turbulence data and wall pressure fluctuations measurements. The third constant is determined by comparing the results of large eddy simulations for a plane channel flow and an annulus flow.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dulat, Falko; Lionetti, Simone; Mistlberger, Bernhard

We present an analytic computation of the Higgs production cross section in the gluon fusion channel, which is differential in the components of the Higgs momentum and inclusive in the associated partonic radiation through NNLO in perturbative QCD. Our computation includes the necessary higher order terms in the dimensional regulator beyond the finite part that are required for renormalisation and collinear factorisation at N 3LO. We outline in detail the computational methods which we employ. We present numerical predictions for realistic final state observables, specifically distributions for the decay products of the Higgs boson in the γγ decay channel.

Higher order explicit symmetric integrators for inseparable forms of coordinates and momenta

NASA Astrophysics Data System (ADS)

Liu, Lei; Wu, Xin; Huang, Guoqing; Liu, Fuyao

2016-06-01

Pihajoki proposed the extended phase-space second-order explicit symmetric leapfrog methods for inseparable Hamiltonian systems. On the basis of this work, we survey a critical problem on how to mix the variables in the extended phase space. Numerical tests show that sequent permutations of coordinates and momenta can make the leapfrog-like methods yield the most accurate results and the optimal long-term stabilized error behaviour. We also present a novel method to construct many fourth-order extended phase-space explicit symmetric integration schemes. Each scheme represents the symmetric production of six usual second-order leapfrogs without any permutations. This construction consists of four segments: the permuted coordinates, triple product of the usual second-order leapfrog without permutations, the permuted momenta and the triple product of the usual second-order leapfrog without permutations. Similarly, extended phase-space sixth, eighth and other higher order explicit symmetric algorithms are available. We used several inseparable Hamiltonian examples, such as the post-Newtonian approach of non-spinning compact binaries, to show that one of the proposed fourth-order methods is more efficient than the existing methods; examples include the fourth-order explicit symplectic integrators of Chin and the fourth-order explicit and implicit mixed symplectic integrators of Zhong et al. Given a moderate choice for the related mixing and projection maps, the extended phase-space explicit symplectic-like methods are well suited for various inseparable Hamiltonian problems. Samples of these problems involve the algorithmic regularization of gravitational systems with velocity-dependent perturbations in the Solar system and post-Newtonian Hamiltonian formulations of spinning compact objects.

Testing the Impact of a Multi-year, Curriculum-based Undergraduate Research Experience (MY-CURE) in the Geosciences: Baseline Observations

NASA Astrophysics Data System (ADS)

Allen, J. L.; Creamer, E. G.; Kuehn, S. C.

2016-12-01

Short-term undergraduate research experiences (URE's) provide skill and confidence enhancement to students, but it is unclear how effective they are in comparison to a dedicated, longer-term URE. This study examines the impact of a long-term URE embedded in a sequence of five courses in the geology curriculum. It begins with a sophomore course in environmental geology, and continues through mineralogy, structural geology, and petrology, before concluding at our summer geology field camp. In this sequence, they build upon individual URE's related to the structure and petrology of fault rocks from a mid-crustal shear zone. Rather than have students engage in one or more short-term URE's, they retain the same project for two calendar years so that we can assess when and how different gains, including a more sophisticated understanding of the nature of science, begin to emerge and mature. As each student progresses, we document the longitudinal development of a diverse suite of gains including: (1) Technical and higher-order research skills, (2) personal gains such as self-identity as a scientist, and (3) communication skills. In this presentation, we describe the framework of the study and baseline observations recorded during the first year of a 2-year cohort. Using a Q-sort method, students were given a deck of 16 index cards with an educational outcome listed on each. They sorted the cards into three piles: Those that encouraged an interest in geology, those that deterred an interest, and those with no impact. Participants discussed the top cards from the negative and positive piles. The top attractors to geology are collegial relationships with faculty, the opportunity to use scientific equipment, field work, the concreteness of geology, and the availability of jobs. Factors that deter interest include hours of tedious homework, math courses, and time invested in wrong answers or failed experiments/sample preparation. Factors not yet evident include confidence in ability to be a scientist, interest in graduate school, and higher-order research skills. These are expected to rise in prominence as the cohort progresses. Early observations underscore the importance of hands-on experience, the concreteness of geology as compared to more person-oriented fields of study, and opportunities for internships and jobs.

Defining Higher-Order Turbulent Moment Closures with an Artificial Neural Network and Random Forest

NASA Astrophysics Data System (ADS)

McGibbon, J.; Bretherton, C. S.

2017-12-01

Unresolved turbulent advection and clouds must be parameterized in atmospheric models. Modern higher-order closure schemes depend on analytic moment closure assumptions that diagnose higher-order moments in terms of lower-order ones. These are then tested against Large-Eddy Simulation (LES) higher-order moment relations. However, these relations may not be neatly analytic in nature. Rather than rely on an analytic higher-order moment closure, can we use machine learning on LES data itself to define a higher-order moment closure?We assess the ability of a deep artificial neural network (NN) and random forest (RF) to perform this task using a set of observationally-based LES runs from the MAGIC field campaign. By training on a subset of 12 simulations and testing on remaining simulations, we avoid over-fitting the training data.Performance of the NN and RF will be assessed and compared to the Analytic Double Gaussian 1 (ADG1) closure assumed by Cloudy Layers Unified By Binormals (CLUBB), a higher-order turbulence closure currently used in the Community Atmosphere Model (CAM). We will show that the RF outperforms the NN and the ADG1 closure for the MAGIC cases within this diagnostic framework. Progress and challenges in using a diagnostic machine learning closure within a prognostic cloud and turbulence parameterization will also be discussed.

Electroneutral models for dynamic Poisson-Nernst-Planck systems

NASA Astrophysics Data System (ADS)

Song, Zilong; Cao, Xiulei; Huang, Huaxiong

2018-01-01

The Poisson-Nernst-Planck (PNP) system is a standard model for describing ion transport. In many applications, e.g., ions in biological tissues, the presence of thin boundary layers poses both modeling and computational challenges. In this paper, we derive simplified electroneutral (EN) models where the thin boundary layers are replaced by effective boundary conditions. There are two major advantages of EN models. First, it is much cheaper to solve them numerically. Second, EN models are easier to deal with compared to the original PNP system; therefore, it would also be easier to derive macroscopic models for cellular structures using EN models. Even though the approach used here is applicable to higher-dimensional cases, this paper mainly focuses on the one-dimensional system, including the general multi-ion case. Using systematic asymptotic analysis, we derive a variety of effective boundary conditions directly applicable to the EN system for the bulk region. This EN system can be solved directly and efficiently without computing the solution in the boundary layer. The derivation is based on matched asymptotics, and the key idea is to bring back higher-order contributions into the effective boundary conditions. For Dirichlet boundary conditions, the higher-order terms can be neglected and the classical results (continuity of electrochemical potential) are recovered. For flux boundary conditions, higher-order terms account for the accumulation of ions in boundary layer and neglecting them leads to physically incorrect solutions. To validate the EN model, numerical computations are carried out for several examples. Our results show that solving the EN model is much more efficient than the original PNP system. Implemented with the Hodgkin-Huxley model, the computational time for solving the EN model is significantly reduced without sacrificing the accuracy of the solution due to the fact that it allows for relatively large mesh and time-step sizes.

Modulational instability, beak-shaped rogue waves, multi-dark-dark solitons and dynamics in pair-transition-coupled nonlinear Schrödinger equations.

PubMed

Zhang, Guoqiang; Yan, Zhenya; Wen, Xiao-Yong

2017-07-01

The integrable coupled nonlinear Schrödinger equations with four-wave mixing are investigated. We first explore the conditions for modulational instability of continuous waves of this system. Secondly, based on the generalized N -fold Darboux transformation (DT), beak-shaped higher-order rogue waves (RWs) and beak-shaped higher-order rogue wave pairs are derived for the coupled model with attractive interaction in terms of simple determinants. Moreover, we derive the simple multi-dark-dark and kink-shaped multi-dark-dark solitons for the coupled model with repulsive interaction through the generalizing DT. We explore their dynamics and classifications by different kinds of spatial-temporal distribution structures including triangular, pentagonal, 'claw-like' and heptagonal patterns. Finally, we perform the numerical simulations to predict that some dark solitons and RWs are stable enough to develop within a short time. The results would enrich our understanding on nonlinear excitations in many coupled nonlinear wave systems with transition coupling effects.

Theoretical scheme of thermal-light many-ghost imaging by Nth-order intensity correlation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Yingchuan; College of Mathematics and Physics, University of South China, Hengyang 421001; Kuang Leman

2011-05-15

In this paper, we propose a theoretical scheme of many-ghost imaging in terms of Nth-order correlated thermal light. We obtain the Gaussian thin lens equations in the many-ghost imaging protocol. We show that it is possible to produce N-1 ghost images of an object at different places in a nonlocal fashion by means of a higher order correlated imaging process with an Nth-order correlated thermal source and correlation measurements. We investigate the visibility of the ghost images in the scheme and obtain the upper bounds of the visibility for the Nth-order correlated thermal-light ghost imaging. It is found that themore » visibility of the ghost images can be dramatically enhanced when the order of correlation becomes larger. It is pointed out that the many-ghost imaging phenomenon is an observable physical effect induced by higher order coherence or higher order correlations of optical fields.« less

Assessment of Higher Order Thinking Skills. Current Perspectives on Cognition, Learning and Instruction

ERIC Educational Resources Information Center

Schraw, Gregory, Ed.; Robinson, Daniel H., Ed.

2011-01-01

This volume examines the assessment of higher order thinking skills from the perspectives of applied cognitive psychology and measurement theory. The volume considers a variety of higher order thinking skills, including problem solving, critical thinking, argumentation, decision making, creativity, metacognition, and self-regulation. Fourteen…

Asymptotic matching by the symbolic manipulator MACSYMA

NASA Technical Reports Server (NTRS)

Lo, L. L.

1985-01-01

The delegation of the labor of calculating higher-order terms in singular perturbation (SP) expansions to a computer by the use of MACSYMA is considered. The method of matched asymptotic expansions is studied in detail for two model SP problems: a model resembling the boundary layer equation with a small parameter multiplying the highest derivatives; and a turning-point problem. It is shown that MACSYMA has successfully performed the higher-order matching in both problems.

Higher order Larmor radius corrections to guiding-centre equations and application to fast ion equilibrium distributions

NASA Astrophysics Data System (ADS)

Lanthaler, S.; Pfefferlé, D.; Graves, J. P.; Cooper, W. A.

2017-04-01

An improved set of guiding-centre equations, expanded to one order higher in Larmor radius than usually written for guiding-centre codes, are derived for curvilinear flux coordinates and implemented into the orbit following code VENUS-LEVIS. Aside from greatly improving the correspondence between guiding-centre and full particle trajectories, the most important effect of the additional Larmor radius corrections is to modify the definition of the guiding-centre’s parallel velocity via the so-called Baños drift. The correct treatment of the guiding-centre push-forward with the Baños term leads to an anisotropic shift in the phase-space distribution of guiding-centres, consistent with the well-known magnetization term. The consequence of these higher order terms are quantified in three cases where energetic ions are usually followed with standard guiding-centre equations: (1) neutral beam injection in a MAST-like low aspect-ratio spherical equilibrium where the fast ion driven current is significantly larger with respect to previous calculations, (2) fast ion losses due to resonant magnetic perturbations where a lower lost fraction and a better confinement is confirmed, (3) alpha particles in the ripple field of the European DEMO where the effect is found to be marginal.

The Politics of French University Reform: Ten Years after May.

ERIC Educational Resources Information Center

Ambler, John S.

1978-01-01

Examines French higher education in terms of Michel Crozier's theory that views the French as torn between two conflicting desires: to maximize personal autonomy and to assure an ordered and orderly environment. Participation on all levels in the university system is described. (AMH)

Stability and Hamiltonian formulation of higher derivative theories

NASA Astrophysics Data System (ADS)

Schmidt, Hans-Jürgen

1994-06-01

We analyze the presuppositions leading to instabilities in theories of order higher than second. The type of fourth-order gravity which leads to an inflationary (quasi-de Sitter) period of cosmic evolution by inclusion of one curvature-squared term (i.e., the Starobinsky model) is used as an example. The corresponding Hamiltonian formulation (which is necessary for deducing the Wheeler-DeWitt equation) is found both in the Ostrogradski approach and in another form. As an example, a closed form solution of the Wheeler-DeWitt equation for a spatially flat Friedmann model and L=R2 is found. The method proposed by Simon to bring fourth order gravity to second order can be (if suitably generalized) applied to bring sixth-order gravity to second order.

Relativistic satellite orbits: central body with higher zonal harmonics

NASA Astrophysics Data System (ADS)

Schanner, Maximilian; Soffel, Michael

2018-06-01

Satellite orbits around a central body with arbitrary zonal harmonics are considered in a relativistic framework. Our starting point is the relativistic Celestial Mechanics based upon the first post-Newtonian approximation to Einstein's theory of gravity as it has been formulated by Damour et al. (Phys Rev D 43:3273-3307, 1991; 45:1017-1044, 1992; 47:3124-3135, 1993; 49:618-635, 1994). Since effects of order (GM/c^2R) × J_k with k ≥ 2 for the Earth are very small (of order 7 × 10^{-10} × J_k) we consider an axially symmetric body with arbitrary zonal harmonics and a static external gravitational field. In such a field the explicit J_k/c^2-terms (direct terms) in the equations of motion for the coordinate acceleration of a satellite are treated first with first-order perturbation theory. The derived perturbation theoretical results of first order have been checked by purely numerical integrations of the equations of motion. Additional terms of the same order result from the interaction of the Newtonian J_k-terms with the post-Newtonian Schwarzschild terms (relativistic terms related to the mass of the central body). These `mixed terms' are treated by means of second-order perturbation theory based on the Lie-series method (Hori-Deprit method). Here we concentrate on the secular drifts of the ascending node <{\\dot{Ω }}> and argument of the pericenter <{\\dot{ω }}>. Finally orders of magnitude are given and discussed.

Optimized equation of the state of the square-well fluid of variable range based on a fourth-order free-energy expansion.

PubMed

Espíndola-Heredia, Rodolfo; del Río, Fernando; Malijevsky, Anatol

2009-01-14

The free energy of square-well (SW) systems of hard-core diameter sigma with ranges 1 < or = lambda < or = 3 is expanded in a perturbation series. This interval covers most ranges of interest, from short-ranged SW fluids (lambda approximately 1.2) used in modeling colloids to long ranges (lambda approximately 3) where the van der Waals classic approximation holds. The first four terms are evaluated by means of extensive Monte Carlo simulations. The calculations are corrected for the thermodynamic limit and care is taken to evaluate and to control the various sources of error. The results for the first two terms in the series confirm well-known independent results but have an increased estimated accuracy and cover a wider set of well ranges. The results for the third- and fourth-order terms are novel. The free-energy expansion for systems with short and intermediate ranges, 1 < or = lambda < or = 2, is seen to have properties similar to those of systems with longer ranges, 2 < or = lambda < or = 3. An equation of state (EOS) is built to represent the free-energy data. The thermodynamics given by this EOS, confronted against independent computer simulations, is shown to predict accurately the internal energy, pressure, specific heat, and chemical potential of the SW fluids considered and for densities 0 < or = rho sigma(3) < or = 0.9 including subcritical temperatures. This fourth-order theory is estimated to be accurate except for a small region at high density, rho sigma(3) approximately 0.9, and low temperature where terms of still higher order might be needed.

Retrospective Analysis of the Post-Operative Changes in Higher-Order Aberrations: A Comparison of the WaveLight EX500 to the VISX S4 Laser in Refractive Surgery.

PubMed

Reed, Donovan S; Apsey, Douglas; Steigleman, Walter; Townley, James; Caldwell, Matthew

2017-11-01

In an attempt to maximize treatment outcomes, refractive surgery techniques are being directed toward customized ablations to correct not only lower-order aberrations but also higher-order aberrations specific to the individual eye. Measurement of the entirety of ocular aberrations is the most definitive means to establish the true effect of refractive surgery on image quality and visual performance. Whether or not there is a statistically significant difference in induced higher-order corneal aberrations between the VISX Star S4 (Abbott Medical Optics, Santa Ana, California) and the WaveLight EX500 (Alcon, Fort Worth, Texas) lasers was examined. A retrospective analysis was performed to investigate the difference in root-mean-square (RMS) value of the higher-order corneal aberrations postoperatively between two currently available laser platforms, the VISX Star S4 and the WaveLight EX500 lasers. The RMS is a compilation of higher-order corneal aberrations. Data from 240 total eyes of active duty military or Department of Defense beneficiaries who completed photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK) refractive surgery at the Wilford Hall Ambulatory Surgical Center Joint Warfighter Refractive Surgery Center were examined. Using SPSS statistics software (IBM Corp., Armonk, New York), the mean changes in RMS values between the two lasers and refractive surgery procedures were determined. A Student t test was performed to compare the RMS of the higher-order aberrations of the subjects' corneas from the lasers being studied. A regression analysis was performed to adjust for preoperative spherical equivalent. The study and a waiver of informed consent have been approved by the Clinical Research Division of the 59th Medical Wing Institutional Review Board (Protocol Number: 20150093H). The mean change in RMS value for PRK using the VISX laser was 0.00122, with a standard deviation of 0.02583. The mean change in RMS value for PRK using the WaveLight EX500 laser was 0.004323, with a standard deviation of 0.02916. The mean change in RMS value for LASIK using the VISX laser was 0.00841, with a standard deviation of 0.03011. The mean change in RMS value for LASIK using the WaveLight EX500 laser was 0.0174, with a standard deviation of 0.02417. When comparing the two lasers for PRK and LASIK procedures, the p values were 0.431 and 0.295, respectively. The results of this study suggest no statistically significant difference concerning induced higher-order aberrations between the two laser platforms for either LASIK or PRK. Overall, the VISX laser did have consistently lower induced higher-order aberrations postoperatively, but this did not reach statistical significance. It is likely the statistical significance of this study was hindered by the power, given the relatively small sample size. Additional limitations of the study include its design, being a retrospective analysis, and the generalizability of the study, as the Department of Defense population may be significantly different from the typical refractive surgery population in terms of overall health and preoperative refractive error. Further investigation of visual outcomes between the two laser platforms should be investigated before determining superiority in terms of visual image and quality postoperatively. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

[Effects of long-term fertilization on microbial biomass carbon and nitrogen and on carbon source utilization of microbes in a red soil].

PubMed

Sun, Feng-xia; Zhang, Wei-hua; Xu, Ming-gang; Zhang, Wen-ju; Li, Zhao-qiang; Zhang, Jing-ye

2010-11-01

In order to explore the effects of long-term fertilization on the microbiological characters of red soil, soil samples were collected from a 19-year long-term experimental field in Qiyang of Hunan, with their microbial biomass carbon (MBC) and nitrogen (MBN) and microbial utilization ratio of carbon sources analyzed. The results showed that after 19-year fertilization, the soil MBC and MBN under the application of organic manure and of organic manure plus inorganic fertilizers were 231 and 81 mg x kg(-1) soil, and 148 and 73 mg x kg(-1) soil, respectively, being significantly higher than those under non-fertilization, inorganic fertilization, and inorganic fertilization plus straw incorporation. The ratio of soil MBN to total N under the application of organic manure and of organic manure plus inorganic fertilizers was averagely 6.0%, significantly higher than that under non-fertilization and inorganic fertilization. Biolog-ECO analysis showed that the average well color development (AWCD) value was in the order of applying organic manure plus inorganic fertilizers = applying organic manure > non-fertilization > inorganic fertilization = inorganic fertilization plus straw incorporation. Under the application of organic manure or of organic manure plus inorganic fertilizers, the microbial utilization rate of carbon sources, including carbohydrates, carboxylic acids, amino acids, polymers, phenols, and amines increased; while under inorganic fertilization plus straw incorporation, the utilization rate of polymers was the highest, and that of carbohydrates was the lowest. Our results suggested that long-term application of organic manure could increase the red soil MBC, MBN, and microbial utilization rate of carbon sources, improve soil fertility, and maintain a better crop productivity.

A Green's function method for high charge and energy ion transport.

PubMed

Chun, S Y; Khandelwal, G S; Wilson, J W

1996-02-01

A heavy-ion transport code using Green's function methods is developed. The low-order perturbation terms exhibiting the greatest energy variation are used as dominant energy-dependent terms, and the higher order collision terms are evaluated using nonperturbative methods. The recently revised NUCFRG database is used to evaluate the solution for comparison with experimental data for 625A MeV 20Ne and 517A MeV 40Ar ion beams. Improved agreements with the attenuation characteristics for neon ions are found, and reasonable agreement is obtained for the transport of argon ions in water.

How long can fisheries management delay action in response to ecosystem and climate change?

PubMed

Brown, Christopher J; Fulton, Elizabeth A; Possingham, Hugh P; Richardson, Anthony J

2012-01-01

Sustainable management of fisheries is often compromised by management delaying implementation of regulations that reduce harvest, in order to maintain higher catches in the short-term. Decreases or increases in fish population growth rate driven by environmental change, including ecosystem and climate change, affect the harvest that can be taken sustainably. If not acted on rapidly, environmental change could result in unsustainable fishing or missed opportunity for higher catches. Using simulation models of harvested fish populations influenced by environmental change, we explore how long fisheries managers can afford to wait before changing harvest regulations in response to changes in population growth. If environmental change causes population declines, delays greater than five years increase the probability of population collapse. Species with fast and highly variable population growth rates are more susceptible to collapse under delays and should be a priority for revised management where delays occur. Generally, the long-term cost of delay, in terms of lost fishing opportunity, exceeds the short-term benefits of overfishing. Lowering harvest limits and monitoring for environmental change can alleviate the impact of delays; however, these measures may be more costly than reducing delays. We recommend that management systems that allow rapid responses to population growth changes be enacted for fisheries management to adapt to ecosystem and climate change.

Effective operators in a single-j orbital

NASA Astrophysics Data System (ADS)

Derbali, E.; Van Isacker, P.; Tellili, B.; Souga, C.

2018-03-01

We present an analysis of effective operators in the shell model with up to three-body interactions in the Hamiltonian and two-body terms in electromagnetic transition operators when the nucleons are either neutrons or protons occupying a single-j orbital. We first show that evidence for an effective three-body interaction exists in the N = 50 isotones and in the lead isotopes but that the separate components of such interaction are difficult to obtain empirically. We then determine higher-order terms on more microscopic grounds. The starting point is a realistic two-body interaction in a large shell-model space together with a standard one-body transition operator, which, after restriction to the dominant orbital and with use of stationary perturbation theory, are transformed into effective versions with higher-order terms. An application is presented for the lead isotopes with neutrons in the 1{g}9/2 orbital.

From 2D to 3D modelling in long term tectonics: Modelling challenges and HPC solutions (Invited)

NASA Astrophysics Data System (ADS)

Le Pourhiet, L.; May, D.

2013-12-01

Over the last decades, 3D thermo-mechanical codes have been made available to the long term tectonics community either as open source (Underworld, Gale) or more limited access (Fantom, Elvis3D, Douar, LaMem etc ...). However, to date, few published results using these methods have included the coupling between crustal and lithospheric dynamics at large strain. The fact that these computations are computational expensive is not the primary reason for the relatively slow development of 3D modeling in the long term tectonics community, as compare to the rapid development observed within the mantle dynamic community, or in the short-term tectonics field. Long term tectonics problems have specific issues not found in either of these two field, including; large strain (not an issue for short-term), the inclusion of free surface and the occurence of large viscosity contrasts. The first issue is typically eliminated using a combined marker-ALE method instead of fully lagrangian method, however, the marker-ALE approach can pose some algorithmic challenges in a massively parallel environment. The two last issues are more problematic because they affect the convergence of the linear/non-linear solver and the memory cost. Two options have been tested so far, using low order element and solving with a sparse direct solver, or using higher order stable elements together with a multi-grid solver. The first options, is simpler to code and to use but reaches its limit at around 80^3 low order elements. The second option requires more operations but allows using iterative solver on extremely large computers. In this presentation, I will describe the design philosophy and highlight results obtained using a code from the second-class method. The presentation will be oriented from an end-user point of view, using an application from 3D continental break up to illustrate key concepts. The description will proceed point by point from implementing physics into the code, to dealing with specific issues related to solving the discrete system of non linear equations.

Identifying and reducing error in cluster-expansion approximations of protein energies.

PubMed

Hahn, Seungsoo; Ashenberg, Orr; Grigoryan, Gevorg; Keating, Amy E

2010-12-01

Protein design involves searching a vast space for sequences that are compatible with a defined structure. This can pose significant computational challenges. Cluster expansion is a technique that can accelerate the evaluation of protein energies by generating a simple functional relationship between sequence and energy. The method consists of several steps. First, for a given protein structure, a training set of sequences with known energies is generated. Next, this training set is used to expand energy as a function of clusters consisting of single residues, residue pairs, and higher order terms, if required. The accuracy of the sequence-based expansion is monitored and improved using cross-validation testing and iterative inclusion of additional clusters. As a trade-off for evaluation speed, the cluster-expansion approximation causes prediction errors, which can be reduced by including more training sequences, including higher order terms in the expansion, and/or reducing the sequence space described by the cluster expansion. This article analyzes the sources of error and introduces a method whereby accuracy can be improved by judiciously reducing the described sequence space. The method is applied to describe the sequence-stability relationship for several protein structures: coiled-coil dimers and trimers, a PDZ domain, and T4 lysozyme as examples with computationally derived energies, and SH3 domains in amphiphysin-1 and endophilin-1 as examples where the expanded pseudo-energies are obtained from experiments. Our open-source software package Cluster Expansion Version 1.0 allows users to expand their own energy function of interest and thereby apply cluster expansion to custom problems in protein design. © 2010 Wiley Periodicals, Inc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frusciante, Noemi; Papadomanolakis, Georgios; Silvestri, Alessandra, E-mail: fruscian@iap.fr, E-mail: papadomanolakis@lorentz.leidenuniv.nl, E-mail: silvestri@lorentz.leidenuniv.nl

We present a generalization of the effective field theory (EFT) formalism for dark energy and modified gravity models to include operators with higher order spatial derivatives. This allows the extension of the EFT framework to a wider class of gravity theories such as Hořava gravity. We present the corresponding extended action, both in the EFT and the Arnowitt-Deser-Misner (ADM) formalism, and proceed to work out a convenient mapping between the two, providing a self contained and general procedure to translate a given model of gravity into the EFT language at the basis of the Einstein-Boltzmann solver EFTCAMB. Putting this mappingmore » at work, we illustrate, for several interesting models of dark energy and modified gravity, how to express them in the ADM notation and then map them into the EFT formalism. We also provide for the first time, the full mapping of GLPV models into the EFT framework. We next perform a thorough analysis of the physical stability of the generalized EFT action, in absence of matter components. We work out viability conditions that correspond to the absence of ghosts and modes that propagate with a negative speed of sound in the scalar and tensor sector, as well as the absence of tachyonic modes in the scalar sector. Finally, we extend and generalize the phenomenological basis in terms of α-functions introduced to parametrize Horndeski models, to cover all theories with higher order spatial derivatives included in our extended action. We elaborate on the impact of the additional functions on physical quantities, such as the kinetic term and the speeds of propagation for scalar and tensor modes.« less

Multicenter evaluation of quality of life and patient satisfaction after breast reconstruction, a long-term retrospective study.

PubMed

Ménez, T; Michot, A; Tamburino, S; Weigert, R; Pinsolle, V

2018-04-01

Breast reconstruction techniques are multiple and they should be chosen in order to improve women's satisfaction and well-being, thus obtaining a personalized treatment. This report's major purpose was to study, through the Breast-Q questionnaire, how the functional and aesthetic outcomes, as well as the complications, of the main autologous breast reconstruction techniques, can affect patients quality of life and well-being at long-term. The secondary purpose was to analyse, thus to identify, the independent factors characterizing the different reconstructive techniques, which may affect patients' satisfaction. Women who underwent autologous breast reconstruction through deep inferior epigastric artery perforator or Latissimus dorsi muscle flap from May 2006 to May 2013 were included. The assessment was based on the Breast-Q reconstruction questionnaire. All times of post-mastectomy reconstruction were concerned: immediate, delayed, after previous procedure failure or conversion to another reconstructive technique due to the patient's dissatisfaction. A total of 98 patients were included. Concerning patients satisfaction, the breast-Q score is highest in patients who underwent immediate breast reconstruction, while scores after delayed breast reconstruction, previous surgery failure or conversion to another technique are generally equivalent. Higher scores have been observed in patients who underwent reconstruction through autologous Latissimus dorsi compared to Latissimus dorsi with prosthetic implant reconstruction. The authors identified factors of higher patients' satisfaction, like absence of major complication and advanced patient's age, in order to personalize the surgical planning according to the patient's priorities. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

An Investigation of Higher-Order Thinking Skills in Smaller Learning Community Social Studies Classrooms

ERIC Educational Resources Information Center

Fischer, Christopher; Bol, Linda; Pribesh, Shana

2011-01-01

This study investigated the extent to which higher-order thinking skills are promoted in social studies classes in high schools that are implementing smaller learning communities (SLCs). Data collection in this mixed-methods study included classroom observations and in-depth interviews. Findings indicated that higher-order thinking was rarely…

Separate Influences of Birth Order and Gravidity/Parity on the Development of Systemic Sclerosis

PubMed Central

COCKRILL, TONYA; del JUNCO, DEBORAH J.; ARNETT, FRANK C.; ASSASSI, SHERVIN; TAN, FILEMON K.; McNEARNEY, TERRY; FISCHBACH, MICHAEL; PERRY, MARILYN; MAYES, MAUREEN D.

2010-01-01

Objective Birth order has been valuable in revealing the role of environmental influences on the risk of developing certain diseases such as allergy and atopy. In addition, pregnancy has profound effects on the immune system such as short-term effects that permit fetal survival as well as longer-term effects that could influence late-onset diseases. In order to better evaluate these influences, we studied the association of birth order and gravidity/parity as risk factors for systemic sclerosis (SSc; scleroderma). Methods Data regarding SSc cases and their unaffected sibling controls were obtained from the Scleroderma Family Registry and DNA Repository. The case-sibling design was used to minimize confounding due to differences in age, race, ethnicity, or calendar time. The gravidity/parity analysis was based on sibships with at least one SSc-affected and one unaffected sister. Results Birth order was examined in 974 sibships, comparing SSc cases (n = 987) with their unaffected siblings (n = 3,088). The risk of scleroderma increased with increasing birth order (odds ratio [OR] 1.25, 95% confidence interval [95% CI] 1.06–1.50 for birth order 2–5; OR 2.22, 95% CI 1.57–3.15 for birth order 6–9; and OR 3.53, 95% CI 1.68–7.45 for birth order 10–15). Gravidity/parity was analyzed in 168 sibships (256 unaffected sisters, 172 SSc cases). We found an association between a history of one or more pregnancies and SSc (OR 2.8). Conclusion Birth order and pregnancy were independently associated with a higher risk of developing SSc. These findings suggest that immune development in early childhood and/or pregnancy-associated events, including but not limited to microchimerism, plays a role in SSc susceptibility. PMID:20391489

Separate influences of birth order and gravidity/parity on the development of systemic sclerosis.

PubMed

Cockrill, Tonya; del Junco, Deborah J; Arnett, Frank C; Assassi, Shervin; Tan, Filemon K; McNearney, Terry; Fischbach, Michael; Perry, Marilyn; Mayes, Maureen D

2010-03-01

Birth order has been valuable in revealing the role of environmental influences on the risk of developing certain diseases such as allergy and atopy. In addition, pregnancy has profound effects on the immune system such as short-term effects that permit fetal survival as well as longer-term effects that could influence late-onset diseases. In order to better evaluate these influences, we studied the association of birth order and gravidity/parity as risk factors for systemic sclerosis (SSc; scleroderma). Data regarding SSc cases and their unaffected sibling controls were obtained from the Scleroderma Family Registry and DNA Repository. The case-sibling design was used to minimize confounding due to differences in age, race, ethnicity, or calendar time. The gravidity/parity analysis was based on sibships with at least one SSc-affected and one unaffected sister. Birth order was examined in 974 sibships, comparing SSc cases (n = 987) with their unaffected siblings (n = 3,088). The risk of scleroderma increased with increasing birth order (odds ratio [OR] 1.25, 95% confidence interval [95% CI] 1.06-1.50 for birth order 2-5; OR 2.22, 95% CI 1.57-3.15 for birth order 6-9; and OR 3.53, 95% CI 1.68-7.45 for birth order 10-15). Gravidity/parity was analyzed in 168 sibships (256 unaffected sisters, 172 SSc cases). We found an association between a history of one or more pregnancies and SSc (OR 2.8). Birth order and pregnancy were independently associated with a higher risk of developing SSc. These findings suggest that immune development in early childhood and/or pregnancy-associated events, including but not limited to microchimerism, plays a role in SSc susceptibility.

Temperature dependent Raman investigation of multiwall carbon nanotubes

NASA Astrophysics Data System (ADS)

Dilawar Sharma, Nita; Singh, Jasveer; Vijay, Aditi

2018-04-01

We report anomalous observations in our investigations of the temperature dependent Raman spectroscopic measurement of multiwall carbon nanotubes. The Micro-Raman spectra were recorded with the laser source having 514.5 nm wavelength and within the temperature range of 80-440 K. The major Raman bands, the G and D band, are observed at 1584 and 1348 cm-1, respectively, at ambient. The absence of the radial breathing mode confirms the multiwall nature of carbon nanotubes. It has been observed that with an increase in the temperature above 120 K, there is a shift in Raman bands towards the higher wave-number region. However, a drop in the G and D bands is observed from 80 to 120 K which was not observed for the second order band. Thereafter, all Raman modes exhibited mode hardening up to about 320 K followed by mild softening of the phonon modes. Linear temperature coefficients were found to have higher contribution to mode hardening as compared to higher order terms. Total anharmonicity estimation shows a predominant effect of the quasi-harmonic term as compared to the true anharmonic term.

Higher-order rogue wave-like solutions for a nonautonomous nonlinear Schrödinger equation with external potentials

NASA Astrophysics Data System (ADS)

Liu, Lei; Tian, Bo; Wu, Xiao-Yu; Sun, Yan

2018-02-01

Under investigation in this paper is the higher-order rogue wave-like solutions for a nonautonomous nonlinear Schrödinger equation with external potentials which can be applied in the nonlinear optics, hydrodynamics, plasma physics and Bose-Einstein condensation. Based on the Kadomtsev-Petviashvili hierarchy reduction, we construct the Nth order rogue wave-like solutions in terms of the Gramian under the integrable constraint. With the help of the analytic and graphic analysis, we exhibit the first-, second- and third-order rogue wave-like solutions through the different dispersion, nonlinearity and linear potential coefficients. We find that only if the dispersion and nonlinearity coefficients are proportional to each other, heights of the background of those rogue waves maintain unchanged with time increasing. Due to the existence of complex parameters, such nonautonomous rogue waves in the higher-order cases have more complex features than those in the lower.

Three-point functions in duality-invariant higher-derivative gravity

DOE PAGES

Naseer, Usman; Zwiebach, Barton

2016-03-21

Here, doubled α'-geometry is the simplest higher-derivative gravitational theory with exact global duality symmetry. We use the double metric formulation of this theory to compute on-shell three-point functions to all orders in α'. A simple pattern emerges when comparing with the analogous bosonic and heterotic three-point functions. As in these theories, the amplitudes factorize. The theory has no Gauss-Bonnet term, but contains a Riemann-cubed interaction to second order in α'.

Front and pulse solutions for the complex Ginzburg-Landau equation with higher-order terms.

PubMed

Tian, Huiping; Li, Zhonghao; Tian, Jinping; Zhou, Guosheng

2002-12-01

We investigate one-dimensional complex Ginzburg-Landau equation with higher-order terms and discuss their influences on the multiplicity of solutions. An exact analytic front solution is presented. By stability analysis for the original partial differential equation, we derive its necessary stability condition for amplitude perturbations. This condition together with the exact front solution determine the region of parameter space where the uniformly translating front solution can exist. In addition, stable pulses, chaotic pulses, and attenuation pulses appear generally if the parameters are out of the range. Finally, applying these analysis into the optical transmission system numerically we find that the stable transmission of optical pulses can be achieved if the parameters are appropriately chosen.

Searching for the full symphony of black hole binary mergers

NASA Astrophysics Data System (ADS)

Harry, Ian; Bustillo, Juan Calderón; Nitz, Alex

2018-01-01

Current searches for the gravitational-wave signature of compact binary mergers rely on matched-filtering data from interferometric observatories with sets of modeled gravitational waveforms. These searches currently use model waveforms that do not include the higher-order mode content of the gravitational-wave signal. Higher-order modes are important for many compact binary mergers and their omission reduces the sensitivity to such sources. In this work we explore the sensitivity loss incurred from omitting higher-order modes. We present a new method for searching for compact binary mergers using waveforms that include higher-order mode effects, and evaluate the sensitivity increase that using our new method would allow. We find that, when evaluating sensitivity at a constant rate-of-false alarm, and when including the fact that signal-consistency tests can reject some signals that include higher-order mode content, we observe a sensitivity increase of up to a factor of 2 in volume for high mass ratio, high total-mass systems. For systems with equal mass, or with total mass ˜50 M⊙, we see more modest sensitivity increases, <10 %, which indicates that the existing search is already performing well. Our new search method is also directly applicable in searches for generic compact binaries.

Data Stewardship and Long-Term Archive of ICESat Data at the National Snow and Ice Data Center (NSIDC)

NASA Astrophysics Data System (ADS)

Fowler, D. K.; Moses, J. F.; Duerr, R. E.; Webster, D.; Korn, D.

2010-12-01

Data Stewardship is becoming a principal part of a data manager’s work at NSIDC. It is vitally important that our organization makes a commitment to both current and long-term goals of data management and the preservation of our scientific data. Data must be available to researchers not only during active missions, but long after missions end. This includes maintaining accurate documentation, data tools, and a knowledgeable user support staff. NSIDC is preparing for long-term support of the ICESat mission data. Though ICESat has seen its last operational day, the data is still being improved and NSIDC is scheduled to archive the final release, Release 33, starting late in 2010. This release will include the final adjustments to the processing algorithms and will produce the best possible products to date. Along with the higher-level data sets, all supporting documentation will be archived at NSIDC. For the long-term archive, it is imperative that there is sufficient information about how products were prepared in order to convince future researchers that the scientific results are reproducible. The processing algorithms along with the Level 0 and ancillary products used to create the higher-level products will be archived and made available to users. This can enable users to examine production history, to derive revised products and to create their own products. Also contained in the long-term archive will be pre-launch, calibration/validation, and test data. These data are an important part of the provenance which must be preserved. For longevity, we’ll need to archive the data and documentation in formats that will be supported in the years to come.

A fixed mass method for the Kramers-Moyal expansion--application to time series with outliers.

PubMed

Petelczyc, M; Żebrowski, J J; Orłowska-Baranowska, E

2015-03-01

Extraction of stochastic and deterministic components from empirical data-necessary for the reconstruction of the dynamics of the system-is discussed. We determine both components using the Kramers-Moyal expansion. In our earlier papers, we obtained large fluctuations in the magnitude of both terms for rare or extreme valued events in the data. Calculations for such events are burdened by an unsatisfactory quality of the statistics. In general, the method is sensitive to the binning procedure applied for the construction of histograms. Instead of the commonly used constant width of bins, we use here a constant number of counts for each bin. This approach-the fixed mass method-allows to include in the calculation events, which do not yield satisfactory statistics in the fixed bin width method. The method developed is general. To demonstrate its properties, here, we present the modified Kramers-Moyal expansion method and discuss its properties by the application of the fixed mass method to four representative heart rate variability recordings with different numbers of ectopic beats. These beats may be rare events as well as outlying, i.e., very small or very large heart cycle lengths. The properties of ectopic beats are important not only for medical diagnostic purposes but the occurrence of ectopic beats is a general example of the kind of variability that occurs in a signal with outliers. To show that the method is general, we also present results for two examples of data from very different areas of science: daily temperatures at a large European city and recordings of traffics on a highway. Using the fixed mass method, to assess the dynamics leading to the outlying events we studied the occurrence of higher order terms of the Kramers-Moyal expansion in the recordings. We found that the higher order terms of the Kramers-Moyal expansion are negligible for heart rate variability. This finding opens the possibility of the application of the Langevin equation to the whole range of empirical signals containing rare or outlying events. Note, however, that the higher order terms are non-negligible for the other data studied here and for it the Langevin equation is not applicable as a model.

A fixed mass method for the Kramers-Moyal expansion—Application to time series with outliers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petelczyc, M.; Żebrowski, J. J.; Orłowska-Baranowska, E.

2015-03-15

Extraction of stochastic and deterministic components from empirical data—necessary for the reconstruction of the dynamics of the system—is discussed. We determine both components using the Kramers-Moyal expansion. In our earlier papers, we obtained large fluctuations in the magnitude of both terms for rare or extreme valued events in the data. Calculations for such events are burdened by an unsatisfactory quality of the statistics. In general, the method is sensitive to the binning procedure applied for the construction of histograms. Instead of the commonly used constant width of bins, we use here a constant number of counts for each bin. Thismore » approach—the fixed mass method—allows to include in the calculation events, which do not yield satisfactory statistics in the fixed bin width method. The method developed is general. To demonstrate its properties, here, we present the modified Kramers-Moyal expansion method and discuss its properties by the application of the fixed mass method to four representative heart rate variability recordings with different numbers of ectopic beats. These beats may be rare events as well as outlying, i.e., very small or very large heart cycle lengths. The properties of ectopic beats are important not only for medical diagnostic purposes but the occurrence of ectopic beats is a general example of the kind of variability that occurs in a signal with outliers. To show that the method is general, we also present results for two examples of data from very different areas of science: daily temperatures at a large European city and recordings of traffics on a highway. Using the fixed mass method, to assess the dynamics leading to the outlying events we studied the occurrence of higher order terms of the Kramers-Moyal expansion in the recordings. We found that the higher order terms of the Kramers-Moyal expansion are negligible for heart rate variability. This finding opens the possibility of the application of the Langevin equation to the whole range of empirical signals containing rare or outlying events. Note, however, that the higher order terms are non-negligible for the other data studied here and for it the Langevin equation is not applicable as a model.« less

One-loop effective actions and higher spins. Part II

NASA Astrophysics Data System (ADS)

Bonora, L.; Cvitan, M.; Prester, P. Dominis; Giaccari, S.; Štemberga, T.

2018-01-01

In this paper we continue and improve the analysis of the effective actions obtained by integrating out a scalar and a fermion field coupled to external symmetric sources, started in the previous paper. The first subject we study is the geometrization of the results obtained there, that is we express them in terms of covariant Jacobi tensors. The second subject concerns the treatment of tadpoles and seagull terms in order to implement off-shell covariance in the initial model. The last and by far largest part of the paper is a repository of results concerning all two point correlators (including mixed ones) of symmetric currents of any spin up to 5 and in any dimensions between 3 and 6. In the massless case we also provide formulas for any spin in any dimension.

Computational electrodynamics in material media with constraint-preservation, multidimensional Riemann solvers and sub-cell resolution - Part II, higher order FVTD schemes

NASA Astrophysics Data System (ADS)

Balsara, Dinshaw S.; Garain, Sudip; Taflove, Allen; Montecinos, Gino

2018-02-01

The Finite Difference Time Domain (FDTD) scheme has served the computational electrodynamics community very well and part of its success stems from its ability to satisfy the constraints in Maxwell's equations. Even so, in the previous paper of this series we were able to present a second order accurate Godunov scheme for computational electrodynamics (CED) which satisfied all the same constraints and simultaneously retained all the traditional advantages of Godunov schemes. In this paper we extend the Finite Volume Time Domain (FVTD) schemes for CED in material media to better than second order of accuracy. From the FDTD method, we retain a somewhat modified staggering strategy of primal variables which enables a very beneficial constraint-preservation for the electric displacement and magnetic induction vector fields. This is accomplished with constraint-preserving reconstruction methods which are extended in this paper to third and fourth orders of accuracy. The idea of one-dimensional upwinding from Godunov schemes has to be significantly modified to use the multidimensionally upwinded Riemann solvers developed by the first author. In this paper, we show how they can be used within the context of a higher order scheme for CED. We also report on advances in timestepping. We show how Runge-Kutta IMEX schemes can be adapted to CED even in the presence of stiff source terms brought on by large conductivities as well as strong spatial variations in permittivity and permeability. We also formulate very efficient ADER timestepping strategies to endow our method with sub-cell resolving capabilities. As a result, our method can be stiffly-stable and resolve significant sub-cell variation in the material properties within a zone. Moreover, we present ADER schemes that are applicable to all hyperbolic PDEs with stiff source terms and at all orders of accuracy. Our new ADER formulation offers a treatment of stiff source terms that is much more efficient than previous ADER schemes. The computer algebra system scripts for generating ADER time update schemes for any general PDE with stiff source terms are also given in the electronic supplements to this paper. Second, third and fourth order accurate schemes for numerically solving Maxwell's equations in material media are presented in this paper. Several stringent tests are also presented to show that the method works and meets its design goals even when material permittivity and permeability vary by an order of magnitude over just a few zones. Furthermore, since the method is unconditionally stable and sub-cell-resolving in the presence of stiff source terms (i.e. for problems involving giant variations in conductivity over just a few zones), it can accurately handle such problems without any reduction in timestep. We also show that increasing the order of accuracy offers distinct advantages for resolving sub-cell variations in material properties. Most importantly, we show that when the accuracy requirements are stringent the higher order schemes offer the shortest time to solution. This makes a compelling case for the use of higher order, sub-cell resolving schemes in CED.

Is What Is Good for General Motors Good for Architecture?

ERIC Educational Resources Information Center

Myrick, Richard; And Others

1966-01-01

Problems of behavioral evaluation and determination of initial building stimuli are discussed in terms of architectural analysis. Application of management research techniques requires problem and goal definition. Analysis of both lower and higher order needs is contingent upon these definitions. Lower order needs relate to more abstract…

On the reach of perturbative methods for dark matter density fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldauf, Tobias; Zaldarriaga, Matias; Schaan, Emmanuel, E-mail: baldauf@ias.edu, E-mail: eschaan@astro.princeton.edu, E-mail: matiasz@ias.edu

We study the mapping from Lagrangian to Eulerian space in the context of the Effective Field Theory (EFT) of Large Scale Structure. We compute Lagrangian displacements with Lagrangian Perturbation Theory (LPT) and perform the full non-perturbative transformation from displacement to density. When expanded up to a given order, this transformation reproduces the standard Eulerian Perturbation Theory (SPT) at the same order. However, the full transformation from displacement to density also includes higher order terms. These terms explicitly resum long wavelength motions, thus making the resulting density field better correlated with the true non-linear density field. As a result, the regimemore » of validity of this approach is expected to extend that of the Eulerian EFT, and match that of the IR-resummed Eulerian EFT. This approach thus effectively enables a test of the IR-resummed EFT at the field level. We estimate the size of stochastic, non-perturbative contributions to the matter density power spectrum. We find that in our highest order calculation, at redshift z = 0 the power spectrum of the density field is reproduced with an accuracy of 1% (10%) up to k = 0.25 hMpc{sup −1} (k = 0.46 hMpc{sup −1}). We believe that the dominant source of the remaining error is the stochastic contribution. Unfortunately, on these scales the stochastic term does not yet scale as k{sup 4} as it does in the very low k regime. Thus, modeling this contribution might be challenging.« less

Linear Static Behavior of Damaged Laminated Composite Plates and Shells

PubMed Central

2017-01-01

A mathematical scheme is proposed here to model a damaged mechanical configuration for laminated and sandwich structures. In particular, two kinds of functions defined in the reference domain of plates and shells are introduced to weaken their mechanical properties in terms of engineering constants: a two-dimensional Gaussian function and an ellipse shaped function. By varying the geometric parameters of these distributions, several damaged configurations are analyzed and investigated through a set of parametric studies. The effect of a progressive damage is studied in terms of displacement profiles and through-the-thickness variations of stress, strain, and displacement components. To this end, a posteriori recovery procedure based on the three-dimensional equilibrium equations for shell structures in orthogonal curvilinear coordinates is introduced. The theoretical framework for the two-dimensional shell model is based on a unified formulation able to study and compare several Higher-order Shear Deformation Theories (HSDTs), including Murakami’s function for the so-called zig-zag effect. Thus, various higher-order models are used and compared also to investigate the differences which can arise from the choice of the order of the kinematic expansion. Their ability to deal with several damaged configurations is analyzed as well. The paper can be placed also in the field of numerical analysis, since the solution to the static problem at issue is achieved by means of the Generalized Differential Quadrature (GDQ) method, whose accuracy and stability are proven by a set of convergence analyses and by the comparison with the results obtained through a commercial finite element software. PMID:28773170

GRAVSAT/GEOPAUSE covariance analysis including geopotential aliasing

NASA Technical Reports Server (NTRS)

Koch, D. W.

1975-01-01

A conventional covariance analysis for the GRAVSAT/GEOPAUSE mission is described in which the uncertainties of approximately 200 parameters, including the geopotential coefficients to degree and order 12, are estimated over three different tracking intervals. The estimated orbital uncertainties for both GRAVSAT and GEOPAUSE reach levels more accurate than presently available. The adjusted measurement bias errors approach the mission goal. Survey errors in the low centimeter range are achieved after ten days of tracking. The ability of the mission to obtain accuracies of geopotential terms to (12, 12) one to two orders of magnitude superior to present accuracy levels is clearly shown. A unique feature of this report is that the aliasing structure of this (12, 12) field is examined. It is shown that uncertainties for unadjusted terms to (12, 12) still exert a degrading effect upon the adjusted error of an arbitrarily selected term of lower degree and order. Finally, the distribution of the aliasing from the unestimated uncertainty of a particular high degree and order geopotential term upon the errors of all remaining adjusted terms is listed in detail.

Systematic review of the neural basis of social cognition in patients with mood disorders

PubMed Central

Cusi, Andrée M.; Nazarov, Anthony; Holshausen, Katherine; MacQueen, Glenda M.; McKinnon, Margaret C.

2012-01-01

Background This review integrates neuroimaging studies of 2 domains of social cognition — emotion comprehension and theory of mind (ToM) — in patients with major depressive disorder and bipolar disorder. The influence of key clinical and method variables on patterns of neural activation during social cognitive processing is also examined. Methods Studies were identified using PsycINFO and PubMed (January 1967 to May 2011). The search terms were “fMRI,” “emotion comprehension,” “emotion perception,” “affect comprehension,” “affect perception,” “facial expression,” “prosody,” “theory of mind,” “mentalizing” and “empathy” in combination with “major depressive disorder,” “bipolar disorder,” “major depression,” “unipolar depression,” “clinical depression” and “mania.” Results Taken together, neuroimaging studies of social cognition in patients with mood disorders reveal enhanced activation in limbic and emotion-related structures and attenuated activity within frontal regions associated with emotion regulation and higher cognitive functions. These results reveal an overall lack of inhibition by higher-order cognitive structures on limbic and emotion-related structures during social cognitive processing in patients with mood disorders. Critically, key variables, including illness burden, symptom severity, comorbidity, medication status and cognitive load may moderate this pattern of neural activation. Limitations Studies that did not include control tasks or a comparator group were included in this review. Conclusion Further work is needed to examine the contribution of key moderator variables and to further elucidate the neural networks underlying altered social cognition in patients with mood disorders. The neural networks underlying higher-order social cognitive processes, including empathy, remain unexplored in patients with mood disorders. PMID:22297065

Thomas-Fermi approximation for a condensate with higher-order interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thoegersen, M.; Jensen, A. S.; Zinner, N. T.

We consider the ground state of a harmonically trapped Bose-Einstein condensate within the Gross-Pitaevskii theory including the effective-range corrections for a two-body zero-range potential. The resulting nonlinear Schroedinger equation is solved analytically in the Thomas-Fermi approximation neglecting the kinetic-energy term. We present results for the chemical potential and the condensate profiles, discuss boundary conditions, and compare to the usual Thomas-Fermi approach. We discuss several ways to increase the influence of effective-range corrections in experiment with magnetically tunable interactions. The level of tuning required could be inside experimental reach in the near future.

Higgs-differential cross section at NNLO in dimensional regularisation

DOE PAGES

Dulat, Falko; Lionetti, Simone; Mistlberger, Bernhard; ...

2017-07-05

We present an analytic computation of the Higgs production cross section in the gluon fusion channel, which is differential in the components of the Higgs momentum and inclusive in the associated partonic radiation through NNLO in perturbative QCD. Our computation includes the necessary higher order terms in the dimensional regulator beyond the finite part that are required for renormalisation and collinear factorisation at N 3LO. We outline in detail the computational methods which we employ. We present numerical predictions for realistic final state observables, specifically distributions for the decay products of the Higgs boson in the γγ decay channel.

Carbon-free hydrogen production from low rank coal

NASA Astrophysics Data System (ADS)

Aziz, Muhammad; Oda, Takuya; Kashiwagi, Takao

2018-02-01

Novel carbon-free integrated system of hydrogen production and storage from low rank coal is proposed and evaluated. To measure the optimum energy efficiency, two different systems employing different chemical looping technologies are modeled. The first integrated system consists of coal drying, gasification, syngas chemical looping, and hydrogenation. On the other hand, the second system combines coal drying, coal direct chemical looping, and hydrogenation. In addition, in order to cover the consumed electricity and recover the energy, combined cycle is adopted as addition module for power generation. The objective of the study is to find the best system having the highest performance in terms of total energy efficiency, including hydrogen production efficiency and power generation efficiency. To achieve a thorough energy/heat circulation throughout each module and the whole integrated system, enhanced process integration technology is employed. It basically incorporates two core basic technologies: exergy recovery and process integration. Several operating parameters including target moisture content in drying module, operating pressure in chemical looping module, are observed in terms of their influence to energy efficiency. From process modeling and calculation, two integrated systems can realize high total energy efficiency, higher than 60%. However, the system employing coal direct chemical looping represents higher energy efficiency, including hydrogen production and power generation, which is about 83%. In addition, optimum target moisture content in drying and operating pressure in chemical looping also have been defined.

Lagrangian and Hamiltonian constraints for guiding-center Hamiltonian theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tronko, Natalia; Brizard, Alain J.

A consistent guiding-center Hamiltonian theory is derived by Lie-transform perturbation method, with terms up to second order in magnetic-field nonuniformity. Consistency is demonstrated by showing that the guiding-center transformation presented here satisfies separate Jacobian and Lagrangian constraints that have not been explored before. A new first-order term appearing in the guiding-center phase-space Lagrangian is identified through a calculation of the guiding-center polarization. It is shown that this new polarization term also yields a simpler expression of the guiding-center toroidal canonical momentum, which satisfies an exact conservation law in axisymmetric magnetic geometries. Finally, an application of the guiding-center Lagrangian constraint onmore » the guiding-center Hamiltonian yields a natural interpretation for its higher-order corrections.« less

Perturbative reduction of derivative order in EFT

NASA Astrophysics Data System (ADS)

Glavan, Dražen

2018-02-01

Higher derivative corrections are ubiquitous in effective field theories, which seemingly introduces new degrees of freedom at successive orders. This is actually an artefact of the implicit local derivative expansion defining effective field theories. We argue that higher derivative corrections that introduce additional degrees of freedom should be removed and their effects captured either by lower derivative corrections, or special combinations of higher derivative corrections not propagating extra degrees of freedom. Three methods adapted for this task are examined and field redefinitions are found to be most appropriate. First order higher derivative corrections in a scalar tensor theory are removed by field redefinition and it is found that their effects are captured by a subset of Horndeski theories. A case is made for restricting the effective field theory expansions in principle to only terms not introducing additional degrees of freedom.

QCD phase diagram using PNJL model with eight-quark interactions

NASA Astrophysics Data System (ADS)

Deb, Paramita; Bhattacharyya, Abhijit; Ghosh, Sanjay K.; Ray, Rajarshi; Lahiri, Anirban

2011-07-01

We present the phase diagram and the fluctuations of different conserved charges like quark number, charge and strangeness at vanishing chemical potential for the 2+1 flavor Polyakov Loop extended Nambu-Jona-Lasinio model with eight-quark interaction terms using three-momentum cutoff regularisation. The main effect of the higher order interaction term is to shift the critical end point to the lower value of the chemical potential and higher value of the temperature. The fluctuations show good qualitative agreement with the lattice data.

Proper orthogonal decomposition-based spectral higher-order stochastic estimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baars, Woutijn J., E-mail: wbaars@unimelb.edu.au; Tinney, Charles E.

A unique routine, capable of identifying both linear and higher-order coherence in multiple-input/output systems, is presented. The technique combines two well-established methods: Proper Orthogonal Decomposition (POD) and Higher-Order Spectra Analysis. The latter of these is based on known methods for characterizing nonlinear systems by way of Volterra series. In that, both linear and higher-order kernels are formed to quantify the spectral (nonlinear) transfer of energy between the system's input and output. This reduces essentially to spectral Linear Stochastic Estimation when only first-order terms are considered, and is therefore presented in the context of stochastic estimation as spectral Higher-Order Stochastic Estimationmore » (HOSE). The trade-off to seeking higher-order transfer kernels is that the increased complexity restricts the analysis to single-input/output systems. Low-dimensional (POD-based) analysis techniques are inserted to alleviate this void as POD coefficients represent the dynamics of the spatial structures (modes) of a multi-degree-of-freedom system. The mathematical framework behind this POD-based HOSE method is first described. The method is then tested in the context of jet aeroacoustics by modeling acoustically efficient large-scale instabilities as combinations of wave packets. The growth, saturation, and decay of these spatially convecting wave packets are shown to couple both linearly and nonlinearly in the near-field to produce waveforms that propagate acoustically to the far-field for different frequency combinations.« less

N-dark-dark solitons for the coupled higher-order nonlinear Schrödinger equations in optical fibers

NASA Astrophysics Data System (ADS)

Zhang, Hai-Qiang; Wang, Yue

2017-11-01

In this paper, we construct the binary Darboux transformation on the coupled higher-order dispersive nonlinear Schrödinger equations in optical fibers. We present the N-fold iterative transformation in terms of the determinants. By the limit technique, we derive the N-dark-dark soliton solutions from the non-vanishing background. Based on the obtained solutions, we find that the collision mechanisms of dark vector solitons exhibit the standard elastic collisions in both two components.

What Do Leaders Think? Reflections on the Implementation of Higher Education Reforms in Armenia

ERIC Educational Resources Information Center

Karakhanyan, Susanna Yuri; van Veen, Klaas; Bergen, Theo C. M.

2012-01-01

Leader perceptions of higher education reforms in Armenia are examined in order to gain an insight into how they view the reforms, their role in the reforms and the roles of others. Semi-structured interviews were conducted with six Armenian higher education leaders and analysed in terms of the following five aspects relevant to leadership: policy…

Formal Solutions for Polarized Radiative Transfer. II. High-order Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janett, Gioele; Steiner, Oskar; Belluzzi, Luca, E-mail: gioele.janett@irsol.ch

When integrating the radiative transfer equation for polarized light, the necessity of high-order numerical methods is well known. In fact, well-performing high-order formal solvers enable higher accuracy and the use of coarser spatial grids. Aiming to provide a clear comparison between formal solvers, this work presents different high-order numerical schemes and applies the systematic analysis proposed by Janett et al., emphasizing their advantages and drawbacks in terms of order of accuracy, stability, and computational cost.

Study on the mapping of dark matter clustering from real space to redshift space

NASA Astrophysics Data System (ADS)

Zheng, Yi; Song, Yong-Seon

2016-08-01

The mapping of dark matter clustering from real space to redshift space introduces the anisotropic property to the measured density power spectrum in redshift space, known as the redshift space distortion effect. The mapping formula is intrinsically non-linear, which is complicated by the higher order polynomials due to indefinite cross correlations between the density and velocity fields, and the Finger-of-God effect due to the randomness of the peculiar velocity field. Whilst the full higher order polynomials remain unknown, the other systematics can be controlled consistently within the same order truncation in the expansion of the mapping formula, as shown in this paper. The systematic due to the unknown non-linear density and velocity fields is removed by separately measuring all terms in the expansion directly using simulations. The uncertainty caused by the velocity randomness is controlled by splitting the FoG term into two pieces, 1) the ``one-point" FoG term being independent of the separation vector between two different points, and 2) the ``correlated" FoG term appearing as an indefinite polynomials which is expanded in the same order as all other perturbative polynomials. Using 100 realizations of simulations, we find that the Gaussian FoG function with only one scale-independent free parameter works quite well, and that our new mapping formulation accurately reproduces the observed 2-dimensional density power spectrum in redshift space at the smallest scales by far, up to k~ 0.2 Mpc-1, considering the resolution of future experiments.

Stability phase diagram of a perpendicular magnetic tunnel junction in noncollinear geometry

NASA Astrophysics Data System (ADS)

Strelkov, N.; Timopheev, A.; Sousa, R. C.; Chshiev, M.; Buda-Prejbeanu, L. D.; Dieny, B.

2017-05-01

Experimental measurements performed on MgO-based perpendicular magnetic tunnel junctions show a strong dependence of the stability voltage-field diagrams as a function of the direction of the magnetic field with respect to the plane of the sample. When the magnetic field is applied in-plane, systematic nonlinear phase boundaries are observed for various lateral sizes. The simulation results based on the phenomenological Landau-Lifshitz-Gilbert equation including the in-plane and out-of-plane spin transfer torques are consistent with the measurements if a second-order anisotropy contribution is considered. Furthermore, performing the stability analysis in linear approximation allowed us to analytically extract the critical switching voltage at zero temperature in the presence of an in-plane field. This study indicates that in the noncollinear geometry investigations are suitable to detect the presence of the second-order term in the anisotropy. Such higher order anisotropy term can yield an easy-cone anisotropy which reduces the thermal stability factor but allows for more reproducible spin transfer torque switching due to a reduced stochasticity of the switching. As a result, the energy per write event decreases much faster than the thermal stability factor as the second-order anisotropy becomes more negative. Easy-cone anisotropy can be useful for fast-switching spin transfer torque magnetic random access memories provided the thermal stability can be maintained above the required value for a given memory specification.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alarcón, Jose Manuel; Du, Dechuan; Klein, Nico

Here, we present a systematic study of neutron-proton scattering in Nuclear Lattice Effective Field Theory (NLEFT), in terms of the computationally efficient radial Hamiltonian method. Our leading-order (LO) interaction consists of smeared, local contact terms and static one-pion exchange. We show results for a fully non-perturbative analysis up to next-to-next-to-leading order (NNLO), followed by a perturbative treatment of contributions beyond LO. The latter analysis anticipates practical Monte Carlo simulations of heavier nuclei. We explore how our results depend on the lattice spacing a, and estimate sources of uncertainty in the determination of the low-energy constants of the next-to-leading-order (NLO) two-nucleonmore » force. We give results for lattice spacings ranging from a = 1.97 fm down to a = 0.98 fm, and discuss the effects of lattice artifacts on the scattering observables. At a = 0.98 fm, lattice artifacts appear small, and our NNLO results agree well with the Nijmegen partial-wave analysis for S-wave and P-wave channels. We expect the peripheral partial waves to be equally well described once the lattice momenta in the pion-nucleon coupling are taken to coincide with the continuum dispersion relation, and higher-order (N 3LO) contributions are included. Finally, we stress that for center-of-mass momenta below 100 MeV, the physics of the two-nucleon system is independent of the lattice spacing.« less

Fourth-order self-energy contribution to the two loop Lamb shift

NASA Astrophysics Data System (ADS)

Palur Mallampalli, Subrahmanyam

1998-11-01

The calculation of the two loop Lamb shift in hydrogenic ions involves the numerical evaluation of ten Feynman diagrams. In this thesis, four fourth-order Feynman diagrams including the pure self-energy contributions are evaluated using exact Dirac-Coulomb propagators, so that higher order binding corrections can be extracted by comparing with the known terms in the Z/alpha expansion. The entire calculation is performed in Feynman gauge. One of the vacuum polarization diagrams is evaluated in the Uehling approximation. At low Z, it is seen to be perturbative in Z/alpha, while new predictions for high Z are made. The calculation of the three self-energy diagrams is reorganized into four terms, which we call the PO, M, F and P terms. The PO term is separately gauge invariant while the latter three form a gauge invariant set. The PO term is shown to exhibit the most non-perturbative behavior yet encountered in QED at low Z, so much so that even at Z = 1, the complete result is of the opposite sign as that of the leading term in its Z/alpha expansion. At high Z, we agree with an earlier calculation. The analysis of ultraviolet divergences in the two loop self-energy is complicated by the presence of sub- divergences. All divergences except the self-mass are shown to cancel. The self-mass is then removed by a self- mass counterterm. Parts of the calculation are shown to contain reference state singularities, that finally cancel. A numerical regulator to handle these singularities is described. The M term, an ultraviolet finite quantity, is defined through a subtraction scheme in coordinate space. Being computationally intensive, it is evaluated only at high Z, specifically Z = 83 and 92. The F term involves the evaluation of several Feynman diagrams with free electron propagators. These are computed for a range of values of Z. The P term, also ultraviolet finite, involves Dirac- Coulomb propagators that are best defined in coordinate space, as well as functions associated with the one loop self-energy that are best defined in momentum space. Possible methods of evaluating the P term are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carney, H.J.; Hass, B.S.

In order to test the thousands of man-made chemicals in the environment for carcinogenic and genetic hazards, a multitude of short-term screening tests has been developed to complement long-term mammalian bioassays and epidemiological studies. These tests cover a broad spectrum of organisms, and include the use of naked and viral nucleic acids, bacteria, fungi, higher plants, insects in vitro mammalian cell cultures (cell transformation, cell-mediated mutagenesis, DNA repair, and chromosome aberration tests) and live mammals. Assay end points include effects on nucleic acids, DNA repair synthesis, point or gene mutation, structural and numerical chromosome aberrations, cytological alterations, and in vitromore » cell transformation. The present review describes and compares these assays. In addition, it discusses their historical development, the problems and limitations associated with their use, and their implementation in comprehensive testing programs. It is intended to provide overview and specific information to the laboratory that is in the process of establishing genetic toxicological systems. (The literature is reviewed to January 1978.)« less

Compensation in Higher Education. ERIC/Higher Education Research Currents.

ERIC Educational Resources Information Center

Trivett, David A.

Compensation in higher education is an inclusive term, since all the benefits associated with teaching, research, work with people, and work with knowledge might be included. But in terms of purchasing power it appears that compensation for work in higher education has lost ground against inflation. In contrast, wage and salary earners in many…

Neutron-proton scattering at next-to-next-to-leading order in Nuclear Lattice Effective Field Theory

DOE PAGES

Alarcón, Jose Manuel; Du, Dechuan; Klein, Nico; ...

2017-05-08

Here, we present a systematic study of neutron-proton scattering in Nuclear Lattice Effective Field Theory (NLEFT), in terms of the computationally efficient radial Hamiltonian method. Our leading-order (LO) interaction consists of smeared, local contact terms and static one-pion exchange. We show results for a fully non-perturbative analysis up to next-to-next-to-leading order (NNLO), followed by a perturbative treatment of contributions beyond LO. The latter analysis anticipates practical Monte Carlo simulations of heavier nuclei. We explore how our results depend on the lattice spacing a, and estimate sources of uncertainty in the determination of the low-energy constants of the next-to-leading-order (NLO) two-nucleonmore » force. We give results for lattice spacings ranging from a = 1.97 fm down to a = 0.98 fm, and discuss the effects of lattice artifacts on the scattering observables. At a = 0.98 fm, lattice artifacts appear small, and our NNLO results agree well with the Nijmegen partial-wave analysis for S-wave and P-wave channels. We expect the peripheral partial waves to be equally well described once the lattice momenta in the pion-nucleon coupling are taken to coincide with the continuum dispersion relation, and higher-order (N 3LO) contributions are included. Finally, we stress that for center-of-mass momenta below 100 MeV, the physics of the two-nucleon system is independent of the lattice spacing.« less

Higher order reconstruction for MRI in the presence of spatiotemporal field perturbations.

PubMed

Wilm, Bertram J; Barmet, Christoph; Pavan, Matteo; Pruessmann, Klaas P

2011-06-01

Despite continuous hardware advances, MRI is frequently subject to field perturbations that are of higher than first order in space and thus violate the traditional k-space picture of spatial encoding. Sources of higher order perturbations include eddy currents, concomitant fields, thermal drifts, and imperfections of higher order shim systems. In conventional MRI with Fourier reconstruction, they give rise to geometric distortions, blurring, artifacts, and error in quantitative data. This work describes an alternative approach in which the entire field evolution, including higher order effects, is accounted for by viewing image reconstruction as a generic inverse problem. The relevant field evolutions are measured with a third-order NMR field camera. Algebraic reconstruction is then formulated such as to jointly minimize artifacts and noise in the resulting image. It is solved by an iterative conjugate-gradient algorithm that uses explicit matrix-vector multiplication to accommodate arbitrary net encoding. The feasibility and benefits of this approach are demonstrated by examples of diffusion imaging. In a phantom study, it is shown that higher order reconstruction largely overcomes variable image distortions that diffusion gradients induce in EPI data. In vivo experiments then demonstrate that the resulting geometric consistency permits straightforward tensor analysis without coregistration. Copyright © 2011 Wiley-Liss, Inc.

Heavy quark form factors at two loops

NASA Astrophysics Data System (ADS)

Ablinger, J.; Behring, A.; Blümlein, J.; Falcioni, G.; De Freitas, A.; Marquard, P.; Rana, N.; Schneider, C.

2018-05-01

We compute the two-loop QCD corrections to the heavy quark form factors in the case of the vector, axial-vector, scalar and pseudoscalar currents up to second order in the dimensional parameter ɛ =(4 -D )/2 . These terms are required in the renormalization of the higher-order corrections to these form factors.

Phase Matching in Presence of Feedback: Higher Order Terms and Enhancement of Nonlinear Interactions

DTIC Science & Technology

2003-12-01

Papers submitted for publication: M. Centini, G. D’Aguanno, L. Sciscione, C. Sibilia, M. Bertolotti, M. Scalora , M. Bloemer: “Phase matching in the...M. Centini, G. D’Aguanno, L. Sciscione, C. Sibilia, M. Bertolotti, M. Scalora , M. Bloemer: “Phase matching in the presence of feedback: High order

Unbound motion on a Schwarzschild background: Practical approaches to frequency domain computations

NASA Astrophysics Data System (ADS)

Hopper, Seth

2018-03-01

Gravitational perturbations due to a point particle moving on a static black hole background are naturally described in Regge-Wheeler gauge. The first-order field equations reduce to a single master wave equation for each radiative mode. The master function satisfying this wave equation is a linear combination of the metric perturbation amplitudes with a source term arising from the stress-energy tensor of the point particle. The original master functions were found by Regge and Wheeler (odd parity) and Zerilli (even parity). Subsequent work by Moncrief and then Cunningham, Price and Moncrief introduced new master variables which allow time domain reconstruction of the metric perturbation amplitudes. Here, I explore the relationship between these different functions and develop a general procedure for deriving new higher-order master functions from ones already known. The benefit of higher-order functions is that their source terms always converge faster at large distance than their lower-order counterparts. This makes for a dramatic improvement in both the speed and accuracy of frequency domain codes when analyzing unbound motion.

Three-dimensional OCT based guinea pig eye model: relating morphology and optics.

PubMed

Pérez-Merino, Pablo; Velasco-Ocana, Miriam; Martinez-Enriquez, Eduardo; Revuelta, Luis; McFadden, Sally A; Marcos, Susana

2017-04-01

Custom Spectral Optical Coherence Tomography (SOCT) provided with automatic quantification and distortion correction algorithms was used to measure the 3-D morphology in guinea pig eyes (n = 8, 30 days; n = 5, 40 days). Animals were measured awake in vivo under cyclopegia. Measurements showed low intraocular variability (<4% in corneal and anterior lens radii and <8% in the posterior lens radii, <1% interocular distances). The repeatability of the surface elevation was less than 2 µm. Surface astigmatism was the individual dominant term in all surfaces. Higher-order RMS surface elevation was largest in the posterior lens. Individual surface elevation Zernike terms correlated significantly across corneal and anterior lens surfaces. Higher-order-aberrations (except spherical aberration) were comparable with those predicted by OCT-based eye models.

Neutron matter within QCD sum rules

NASA Astrophysics Data System (ADS)

Cai, Bao-Jun; Chen, Lie-Wen

2018-05-01

The equation of state (EOS) of pure neutron matter (PNM) is studied in QCD sum rules (QCDSRs ). It is found that the QCDSR results on the EOS of PNM are in good agreement with predictions by current advanced microscopic many-body theories. Moreover, the higher-order density terms in quark condensates are shown to be important to describe the empirical EOS of PNM in the density region around and above nuclear saturation density although they play a minor role at subsaturation densities. The chiral condensates in PNM are also studied, and our results indicate that the higher-order density terms in quark condensates, which are introduced to reasonably describe the empirical EOS of PNM at suprasaturation densities, tend to hinder the appearance of chiral symmetry restoration in PNM at high densities.

Anomalous diffusion with linear reaction dynamics: from continuous time random walks to fractional reaction-diffusion equations.

PubMed

Henry, B I; Langlands, T A M; Wearne, S L

2006-09-01

We have revisited the problem of anomalously diffusing species, modeled at the mesoscopic level using continuous time random walks, to include linear reaction dynamics. If a constant proportion of walkers are added or removed instantaneously at the start of each step then the long time asymptotic limit yields a fractional reaction-diffusion equation with a fractional order temporal derivative operating on both the standard diffusion term and a linear reaction kinetics term. If the walkers are added or removed at a constant per capita rate during the waiting time between steps then the long time asymptotic limit has a standard linear reaction kinetics term but a fractional order temporal derivative operating on a nonstandard diffusion term. Results from the above two models are compared with a phenomenological model with standard linear reaction kinetics and a fractional order temporal derivative operating on a standard diffusion term. We have also developed further extensions of the CTRW model to include more general reaction dynamics.

A physical optics/equivalent currents model for the RCS of trihedral corner reflectors

NASA Technical Reports Server (NTRS)

Balanis, Constantine A.; Polycarpou, Anastasis C.

1993-01-01

The scattering in the interior regions of both square and triangular trihedral corner reflectors is examined. The theoretical model presented combines geometrical and physical optics (GO and PO), used to account for reflection terms, with equivalent edge currents (EEC), used to account for first-order diffractions from the edges. First-order, second-order, and third-order reflection terms are included. Calculating the first-order reflection terms involves integrating over the entire surface of the illuminated plate. Calculating the second- and third-order reflection terms, however, is much more difficult because the illuminated area is an arbitrary polygon whose shape is dependent upon the incident angles. The method for determining the area of integration is detailed. Extensive comparisons between the high-frequency model, Finite-Difference Time-Domain (FDTD) and experimental data are used for validation of the radar cross section (RCS) of both square and triangular trihedral reflectors.

Factorization and resummation: A new paradigm to improve gravitational wave amplitudes. II. The higher multipolar modes

NASA Astrophysics Data System (ADS)

Messina, Francesco; Maldarella, Alberto; Nagar, Alessandro

2018-04-01

The factorization and resummation approach of Nagar and Shah [Phys. Rev. D 94, 104017 (2016), 10.1103/PhysRevD.94.104017], designed to improve the strong-field behavior of the post-Newtonian (PN) residual waveform amplitudes fℓm's entering the effective-one-body, circularized, gravitational waveform for spinning coalescing binaries, is improved and generalized here to all multipoles up to ℓ=6 . For a test particle orbiting a Kerr black hole, each multipolar amplitude is truncated at relative 6 PN order, both for the orbital (nonspinning) and spin factors. By taking a certain Padé approximant (typically the P24 one) of the orbital factor in conjunction with the inverse Taylor (iResum) representation of the spin factor, it is possible to push the analytical/numerical agreement of the energy flux at the level of 5% at the last-stable orbit for a quasimaximally spinning black hole with dimensionless spin parameter +0.99 . When the procedure is generalized to comparable-mass binaries, each orbital factor is kept at relative 3+3 PN order; i.e., the globally 3 PN-accurate comparable-mass terms are hybridized with higher-PN test-particle terms up to 6 PN relative order in each mode. The same Padé resummation is used for continuity. By contrast, the spin factor is only kept at the highest comparable-mass PN order currently available. We illustrate that the consistency between different truncations in the spin content of the waveform amplitudes is more marked in the resummed case than when using the standard Taylor-expanded form of Pan et al. [Phys. Rev. D 83, 064003 (2011), 10.1103/PhysRevD.83.064003]. We finally introduce a method to consistently hybridize comparable-mass and test-particle information also in the presence of spin (including the spin of the particle), discussing it explicitly for the ℓ=m =2 spin-orbit and spin-square terms. The improved, factorized and resummed, multipolar waveform amplitudes presented here are expected to set a new standard for effective one body-based gravitational waveform models.

Predicting the dry deposition of atmospheric aerosol particles onto forests using a size-resolved multi-layer second-order closure model

NASA Astrophysics Data System (ADS)

Huang, C.; Launianen, S.; Gronholm, T.; Katul, G. G.

2013-12-01

Biological aerosol particles are now receiving significant attention given their role in air quality, climate change, and spreading of allergens and other communicable diseases. A major uncertainty in their quantification is associated with complex transport processes governing their generation and removal inside canopies. It has been known for some time now that the commonly used first-order closure to link mean concentration gradients with turbulent fluxes is problematic. The presence of a mean counter-gradient momentum transport in an open trunk space exemplifies such failure. Here, instead of employing K-theory, a size-resolved second-order multilayer model for dry particle deposition is proposed. The starting point of the proposed model is a particle flux budget in which the production, transport, and dissipation terms are modeled. Because these terms require higher-order velocity statistics, this flux budget is coupled with a conventional second-order closure scheme for the flow field within the canopy sub-layer. The failure of conventional K-theory for particle fluxes are explicitly linked to the onset of a mean counter or zero - gradient flow attributed to a significant particle flux transport term. The relative importance of these terms in the particle flux budget and their effects on the foliage particle collection terms for also discussed for each particle size. The proposed model is evaluated against published multi-level measurements of sized-resolved particle fluxes and mean concentration profiles collected within and above a tall Scots pine forest in Hyytiala, Southern Finland. The main findings are that (1) first-order closure schemes may be still plausible for modeling particle deposition velocity, especially in the particle size range smaller than 1 μm when the turbulent particle diffusivity is estimated from higher order flow statistics; (2) the mechanisms leading to the increased trend of particle deposition velocity with increasing friction velocity differ for different particle sizes and different levels (i.e. above and below the canopy); (3) the partitioning of particle deposition onto foliage and forest floor appears insensitive to friction velocity for particles smaller than 100 nm, but decreases with increasing friction velocity for particles large than 100 nm.

Engaging Adolescents with LD in Higher Order Thinking about History Concepts Using Integrated Content Enhancement Routines

ERIC Educational Resources Information Center

Bulgren, Janis; Deshler, Donald D.; Lenz, B. Keith

2007-01-01

The understanding and use of historical concepts specified in national history standards pose many challenges to students. These challenges include both the acquisition of content knowledge and the use of that knowledge in ways that require higher order thinking. All students, including adolescents with learning disabilities (LD), are expected to…

Enhancing Higher Order Thinking Skills Among Inservice Science Teachers Via Embedded Assessment

NASA Astrophysics Data System (ADS)

Barak, Miri; Dori, Yehudit Judy

2009-10-01

Testing students on higher order thinking skills may reinforce these skills among them. To research this assertion, we developed a graduate course for inservice science teachers in a framework of a “Journal Club”—a hybrid course which combines face-to-face classroom discussions with online activities, interrelating teaching, learning, and assessment. The course involves graduate students in critical evaluation of science education articles and cognitive debates, and tests them on these skills. Our study examined the learning processes and outcomes of 51 graduate students, from three consecutive semesters. Findings indicated that the students’ higher order thinking skills were enhanced in terms of their ability to (a) pose complex questions, (b) present solid opinions, (c) introduce consistent arguments, and (d) demonstrate critical thinking.

Computation of rapidly varied unsteady, free-surface flow

USGS Publications Warehouse

Basco, D.R.

1987-01-01

Many unsteady flows in hydraulics occur with relatively large gradients in free surface profiles. The assumption of hydrostatic pressure distribution with depth is no longer valid. These are rapidly-varied unsteady flows (RVF) of classical hydraulics and also encompass short wave propagation of coastal hydraulics. The purpose of this report is to present an introductory review of the Boussinnesq-type differential equations that describe these flows and to discuss methods for their numerical integration. On variable slopes and for large scale (finite-amplitude) disturbances, three independent derivational methods all gave differences in the motion equation for higher order terms. The importance of these higher-order terms for riverine applications must be determined by numerical experiments. Care must be taken in selection of the appropriate finite-difference scheme to minimize truncation error effects and the possibility of diverging (double mode) numerical solutions. It is recommended that practical hydraulics cases be established and tested numerically to demonstrate the order of differences in solution with those obtained from the long wave equations of St. Venant. (USGS)

Few-cycle optical rogue waves: complex modified Korteweg-de Vries equation.

PubMed

He, Jingsong; Wang, Lihong; Li, Linjing; Porsezian, K; Erdélyi, R

2014-06-01

In this paper, we consider the complex modified Korteweg-de Vries (mKdV) equation as a model of few-cycle optical pulses. Using the Lax pair, we construct a generalized Darboux transformation and systematically generate the first-, second-, and third-order rogue wave solutions and analyze the nature of evolution of higher-order rogue waves in detail. Based on detailed numerical and analytical investigations, we classify the higher-order rogue waves with respect to their intrinsic structure, namely, fundamental pattern, triangular pattern, and ring pattern. We also present several new patterns of the rogue wave according to the standard and nonstandard decomposition. The results of this paper explain the generalization of higher-order rogue waves in terms of rational solutions. We apply the contour line method to obtain the analytical formulas of the length and width of the first-order rogue wave of the complex mKdV and the nonlinear Schrödinger equations. In nonlinear optics, the higher-order rogue wave solutions found here will be very useful to generate high-power few-cycle optical pulses which will be applicable in the area of ultrashort pulse technology.

The Hollow University: Disaster Capitalism Befalls American Higher Education

ERIC Educational Resources Information Center

Letizia, Angelo J.

2016-01-01

Over the last 40 years, American institutions of higher education have been encouraged to align with the private sector by policymakers, think tank experts and businessmen in order to become more efficient and more accountable. In a wider sense, this new partnership may be evidence of what has been termed "disaster capitalism." In…

The role of higher-order terms in perturbation approaches to the monomer and\\xA0bonding contributions in a SAFT-type equation of state for square-well chain\\xA0fluids

NASA Astrophysics Data System (ADS)

Solana, J. R.; Akhouri, B. P.

2018-07-01

A perturbation theory for square-well chain fluids is developed within the scheme of the (generalised) Wertheim thermodynamic perturbation theory. The theory is based on the Pavlyukhin parametrisations [Y. T. Pavlyukhin, J. Struct. Chem. 53, 476 (2012)] of their simulation data for the first four perturbation terms in the high temperature expansion of the Helmholtz free energy of square-well monomer fluids combined with a second-order perturbation theory for the contact value of the radial distribution function of the square-well monomer fluid that enters into bonding contribution. To obtain the latter perturbation terms, we have performed computer simulations in the hard-sphere reference system. The importance of the perturbation terms beyond the second-order one for the monomer fluid and of the approximations of different orders in the bonding contribution for the chain fluids in the predicted equation of state, excess energy and liquid-vapour coexistence densities is analysed.

48 CFR 552.238-78 - Scope of Contract (Eligible Ordering Activities).

Code of Federal Regulations, 2010 CFR

2010-10-01

... educational agency or institution of higher learning). (e) Articles or services may be ordered from time to... (including any local educational agency or institution of higher learning). State and local government...

Longitudinal-Transverse Separation of Deep-Inelastic Scattering at Low Q² on Nucleons and Nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tvaskis, Vladas

2004-12-06

Since the early experiments at SLAC, which discovered the nucleon substructure and led to the development of the quark parton model, deep inelastic scattering (DIS) has been the most powerful tool to investigate the partonic substructure of the nucleon. After about 30 years of experiments with electron and muon beams the nucleon structure function F 2(x,Q 2) is known with high precision over about four orders of magnitude in x and Q 2. In the region of Q 2 > 1 (GeV/c) 2 the results of the DIS measurements are interpreted in terms of partons (quarks and gluons). The theoreticalmore » framework is provided in this case by perturbative Quantum Chromo Dynamics (pQCD), which includes scaling violations, as described by the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equations. The description starts to fail when Q 2 becomes of the order of 1 (GeV/c) 2, where non-perturbative effects (higher-twist effects), which are still not fully understood, become important (non-pQCD). The sensitivity for order-n twist effects increases with decreasing Q 2, since they include a factor 1/(Q 2n) (n ≥ 1).« less

Anomalous current from the covariant Wigner function

NASA Astrophysics Data System (ADS)

Prokhorov, George; Teryaev, Oleg

2018-04-01

We consider accelerated and rotating media of weakly interacting fermions in local thermodynamic equilibrium on the basis of kinetic approach. Kinetic properties of such media can be described by covariant Wigner function incorporating the relativistic distribution functions of particles with spin. We obtain the formulae for axial current by summation of the terms of all orders of thermal vorticity tensor, chemical potential, both for massive and massless particles. In the massless limit all the terms of fourth and higher orders of vorticity and third order of chemical potential and temperature equal zero. It is shown, that axial current gets a topological component along the 4-acceleration vector. The similarity between different approaches to baryon polarization is established.

High-order flux correction/finite difference schemes for strand grids

NASA Astrophysics Data System (ADS)

Katz, Aaron; Work, Dalon

2015-02-01

A novel high-order method combining unstructured flux correction along body surfaces and high-order finite differences normal to surfaces is formulated for unsteady viscous flows on strand grids. The flux correction algorithm is applied in each unstructured layer of the strand grid, and the layers are then coupled together via a source term containing derivatives in the strand direction. Strand-direction derivatives are approximated to high-order via summation-by-parts operators for first derivatives and second derivatives with variable coefficients. We show how this procedure allows for the proper truncation error canceling properties required for the flux correction scheme. The resulting scheme possesses third-order design accuracy, but often exhibits fourth-order accuracy when higher-order derivatives are employed in the strand direction, especially for highly viscous flows. We prove discrete conservation for the new scheme and time stability in the absence of the flux correction terms. Results in two dimensions are presented that demonstrate improvements in accuracy with minimal computational and algorithmic overhead over traditional second-order algorithms.

Application of a symmetric total variation diminishing scheme to aerodynamics of rotors

NASA Astrophysics Data System (ADS)

Usta, Ebru

2002-09-01

The aerodynamics characteristics of rotors in hover have been studied on stretched non-orthogonal grids using spatially high order symmetric total variation diminishing (STVD) schemes. Several companion numerical viscosity terms have been tested. The effects of higher order metrics, higher order load integrations and turbulence effects on the rotor performance have been studied. Where possible, calculations for 1-D and 2-D benchmark problems have been done on uniform grids, and comparisons with exact solutions have been made to understand the dispersion and dissipation characteristics of these algorithms. A baseline finite volume methodology termed TURNS (Transonic Unsteady Rotor Navier-Stokes) is the starting point for this effort. The original TURNS solver solves the 3-D compressible Navier-Stokes equations in an integral form using a third order upwind scheme. It is first or second order accurate in time. In the modified solver, the inviscid flux at a cell face is decomposed into two parts. The first part of the flux is symmetric in space, while the second part consists of an upwind-biased numerical viscosity term. The symmetric part of the flux at the cell face is computed to fourth-, sixth- or eighth order accuracy in space. The numerical viscosity portion of the flux is computed using either a third order accurate MUSCL scheme or a fifth order WENO scheme. A number of results are presented for the two-bladed Caradonna-Tung rotor and for a four-bladed UH-60A rotor in hover. Comparisons with the original TURNS code, and experiments are given. Results are also presented on the effects of metrics calculations, load integration algorithms, and turbulence models on the solution accuracy. A total of 64 combinations were studied in this thesis work. For brevity, only a small subset of results highlighting the most important conclusions are presented. It should be noted that use of higher order formulations did not affect the temporal stability of the algorithm and did not require any reduction in the time step. The calculations show that the solution accuracy increases when the 3 rd order upwind scheme in the baseline algorithm is replaced with 4th and 6th order accurate symmetric flux calculations. A point of diminishing returns is reached as increasingly larger stencils are used on highly stretched grids. The numerical viscosity term, when computed with the third order MUSCL scheme, is very dissipative, and does not resolve the tip vortex well. The WENO5 scheme, on the other hand significantly improves the tip vortex capturing. The STVD6+WENO5 scheme, in particular gave the best combinations of solution accuracy and efficiency on stretched grids. Spatially fourth order accurate metric calculations were found to be beneficial, but should be used in conjunction with a limiter that drops the metric calculation to a second order accuracy in the vicinity of grid discontinuities. High order integration of loads was found to have a beneficial, but small effect on the computed loads. Replacing the Baldwin-Lomax turbulence model with a one equation Spalart-Allmaras model resulted in higher than expected profile power contributions. Nevertheless the one-equation model is recommended for its robustness, its ability to model separated flows at high thrust settings, and the natural manner in which turbulence in the rotor wake may be treated.

Low Dissipative High Order Shock-Capturing Methods Using Characteristic-Based Filters

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sandham, N. D.; Djomehri, M. J.

1998-01-01

An approach which closely maintains the non-dissipative nature of classical fourth or higher- order spatial differencing away from shock waves and steep gradient regions while being capable of accurately capturing discontinuities, steep gradient and fine scale turbulent structures in a stable and efficient manner is described. The approach is a generalization of the method of Gustafsson and Oisson and the artificial compression method (ACM) of Harten. Spatially non-dissipative fourth or higher-order compact and non-compact spatial differencings are used as the base schemes. Instead of applying a scalar filter as in Gustafsson and Olsson, an ACM like term is used to signal the appropriate amount of second or third-order TVD or ENO types of characteristic based numerical dissipation. This term acts as a characteristic filter to minimize numerical dissipation for the overall scheme. For time-accurate computations, time discretizations with low dissipation are used. Numerical experiments on 2-D vortical flows, vortex-shock interactions and compressible spatially and temporally evolving mixing layers showed that the proposed schemes have the desired property with only a 10% increase in operations count over standard second-order TVD schemes. Aside from the ability to accurately capture shock-turbulence interaction flows, this approach is also capable of accurately preserving vortex convection. Higher accuracy is achieved with fewer grid points when compared to that of standard second-order TVD or ENO schemes. To demonstrate the applicability of these schemes in sustaining turbulence where shock waves are absent, a simulation of 3-D compressible turbulent channel flow in a small domain is conducted.

Low Dissipative High Order Shock-Capturing Methods using Characteristic-Based Filters

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sandham, N. D.; Djomehri, M. J.

1998-01-01

An approach which closely maintains the non-dissipative nature of classical fourth or higher- order spatial differencing away from shock waves and steep gradient regions while being capable of accurately capturing discontinuities, steep gradient and fine scale turbulent structures in a stable and efficient manner is described. The approach is a generalization of the method of Gustafsson and Olsson and the artificial compression method (ACM) of Harten. Spatially non-dissipative fourth or higher-order compact and non-compact spatial differencings are used as the base schemes. Instead of applying a scalar filter as in Gustafsson and Olsson, an ACM like term is used to signal the appropriate amount of second or third-order TVD or ENO types of characteristic based numerical dissipation. This term acts as a characteristic filter to minimize numerical dissipation for the overall scheme. For time-accurate computations, time discretizations with low dissipation are used. Numerical experiments on 2-D vortical flows, vortex-shock interactions and compressible spatially and temporally evolving mixing layers showed that the proposed schemes have the desired property with only a 10% increase in operations count over standard second-order TVD schemes. Aside from the ability to accurately capture shock-turbulence interaction flows, this approach is also capable of accurately preserving vortex convection. Higher accuracy is achieved with fewer grid points when compared to that of standard second-order TVD or ENO schemes. To demonstrate the applicability of these schemes in sustaining turbulence where shock waves are absent, a simulation of 3-D compressible turbulent channel flow in a small domain is conducted.

Improved knowledge retention among clinical pharmacy students using an anthropology classroom assessment technique.

PubMed

Whitley, Heather P; Parton, Jason M

2014-09-15

To adapt a classroom assessment technique (CAT) from an anthropology course to a diabetes module in a clinical pharmacy skills laboratory and to determine student knowledge retention from baseline. Diabetes item stems, focused on module objectives, replaced anthropology terms. Answer choices, coded to Bloom's Taxonomy, were expanded to include higher-order thinking. Students completed the online 5-item probe 4 times: prelaboratory lecture, postlaboratory, and at 6 months and 12 months after laboratory. Statistical analyses utilized a single factor, repeated measures design using rank transformations of means with a Mann-Whitney-Wilcoxon test. The CAT revealed a significant increase in knowledge from prelaboratory compared to all postlaboratory measurements (p<0.0001). Significant knowledge retention was maintained with basic terms, but declined with complex terms between 6 and 12 months. The anthropology assessment tool was effectively adapted using Bloom's Taxonomy as a guide and, when used repeatedly, demonstrated knowledge retention. Minimal time was devoted to application of the probe making it an easily adaptable CAT.

Long-range, collision-induced hyperpolarizabilities of atoms or centrosymmetric linear molecules: Theory and numerical results for pairs containing H or He

NASA Astrophysics Data System (ADS)

Li, Xiaoping; Hunt, Katharine L. C.; Pipin, Janusz; Bishop, David M.

1996-12-01

For atoms or molecules of D∞h or higher symmetry, this work gives equations for the long-range, collision-induced changes in the first (Δβ) and second (Δγ) hyperpolarizabilities, complete to order R-7 in the intermolecular separation R for Δβ, and order R-6 for Δγ. The results include nonlinear dipole-induced-dipole (DID) interactions, higher multipole induction, induction due to the nonuniformity of the local fields, back induction, and dispersion. For pairs containing H or He, we have used ab initio values of the static (hyper)polarizabilities to obtain numerical results for the induction terms in Δβ and Δγ. For dispersion effects, we have derived analytic results in the form of integrals of the dynamic (hyper)polarizabilities over imaginary frequencies, and we have evaluated these numerically for the pairs H...H, H...He, and He...He using the values of the fourth dipole hyperpolarizability ɛ(-iω; iω, 0, 0, 0, 0) obtained in this work, along with other hyperpolarizabilities calculated previously by Bishop and Pipin. For later numerical applications to molecular pairs, we have developed constant ratio approximations (CRA1 and CRA2) to estimate the dispersion effects in terms of static (hyper)polarizabilities and van der Waals energy or polarizability coefficients. Tests of the approximations against accurate results for the pairs H...H, H...He, and He...He show that the root mean square (rms) error in CRA1 is ˜20%-25% for Δβ and Δγ; for CRA2 the error in Δβ is similar, but the rms error in Δγ is less than 4%. At separations ˜1.0 a.u. outside the van der Waals minima of the pair potentials for H...H, H...He, and He...He, the nonlinear DID interactions make the dominant contributions to Δγzzzz (where z is the interatomic axis) and to Δγxxxx, accounting for ˜80%-123% of the total value. Contributions due to higher-multipole induction and the nonuniformity of the local field (Qα terms) may exceed 15%, while dispersion effects contribute ˜4%-9% of the total Δγzzzz and Δγxxxx. For Δγxxzz, the α term is roughly equal to the nonlinear DID term in absolute value, but opposite in sign. Other terms in Δγxxzz are smaller, but they are important in determining its net value because of the near cancellation of the two dominant terms. When Δγ is averaged isotropically over the orientations of the interatomic vector to give Δγ¯, dispersion effects dominate, contributing 76% of the total Δγ¯ (through order R-6) for H...H, 81% for H...He, and 73% for He...He.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Cheong R.

The structural changes of kinetic Alfvén solitary waves (KASWs) due to higher-order terms are investigated. While the first-order differential equation for KASWs provides the dispersion relation for kinetic Alfvén waves, the second-order differential equation describes the structural changes of the solitary waves due to higher-order nonlinearity. The reductive perturbation method is used to obtain the second-order and third-order partial differential equations; then, Kodama and Taniuti's technique [J. Phys. Soc. Jpn. 45, 298 (1978)] is applied in order to remove the secularities in the third-order differential equations and derive a linear second-order inhomogeneous differential equation. The solution to this new second-ordermore » equation indicates that, as the amplitude increases, the hump-type Korteweg-de Vries solution is concentrated more around the center position of the soliton and that dip-type structures form near the two edges of the soliton. This result has a close relationship with the interpretation of the complex KASW structures observed in space with satellites.« less

Racial Differences In Hospitalizations Among Medicare-Medicaid Dual Eligible Dying Nursing Home Residents

PubMed Central

Cai, Shubing; Miller, Susan C.; Mukamel, Dana B.

2016-01-01

Objectives To examine whether racial differences in end of life (EOL) hospitalizations vary by the presence of advance directives, specifically the Do-Not-Hospitalize (DNH) order and individual cognitive status, among nursing home (NH) residents. Design National data, including the Medicare data and the Minimum Data Set (MDS) 2.0, between 01/01/2007 and 09/30/2010 were linked. EOL hospitalizations were hospitalizations in the last 30 days of life. Linear probability models with an interaction term (between race and DNH) and NH fixed-effects were estimated. The analyses were stratified by individual cognitive status. Setting NHs in the U.S. Participants We included decedents who were Medicare-Medicaid dually eligible, enrolled in Medicare fee-for-service plans and NH long-stayers (i.e., in NHs at least 90 days before their death). In total, 394,948 decedents were identified. Measurements The racial difference in EOL hospitalizations from a NH. Results EOL hospitalization rate was 31.7% for whites and 42.8% for blacks. Among those without DNH orders, adjusted probabilities of EOL hospitalizations were higher for blacks than for whites: 2.7 percentage points among those moderate cognitive impairment, P<0.01; and 4.7 percentage points among those with severe cognitive impairment, P<0.01. Among those with DNH orders, adjusted racial differences in EOL hospitalizations were not statistically significant among those with moderate or severe cognitive impairment (P=0.25 and 0.93), but blacks had a higher probability of EOL hospitalizations than whites if they had relatively intact cognitive status. Conclusion Racial differences in EOL hospitalizations varied with DNH orders and cognitive status among dying residents. Future research is necessary to understand the reasons behind these variations. PMID:27549337

Lifestyle modification in the management of the metabolic syndrome: achievements and challenges

PubMed Central

Grave, Riccardo Dalle; Calugi, Simona; Centis, Elena; Marzocchi, Rebecca; Ghoch, Marwan El; Marchesini, Giulio

2010-01-01

Lifestyle modification based on behavior therapy is the most important and effective strategy to manage the metabolic syndrome. Modern lifestyle modification therapy combines specific recommendations on diet and exercise with behavioral and cognitive strategies. The intervention may be delivered face-to-face or in groups, or in groups combined with individual sessions. The main challenge of treatment is helping patients maintain healthy behavior changes in the long term. In the last few years, several strategies have been evaluated to improve the long-term effect of lifestyle modification. Promising results have been achieved by combining lifestyle modification with pharmacotherapy, using meals replacement, setting higher physical activity goals, and long-term care. The key role of cognitive processes in the success/failure of weight loss and maintenance suggests that new cognitive procedures and strategies should be included in the traditional lifestyle modification interventions, in order to help patients build a mind-set favoring long-term lifestyle changes. These new strategies raise optimistic expectations for an effective treatment of metabolic syndrome with lifestyle modifications, provided public health programs to change the environment where patients live support them. PMID:21437107

Feasibility of Higher-Order Differential Ion Mobility Separations Using New Asymmetric Waveforms

PubMed Central

Shvartsburg, Alexandre A.; Mashkevich, Stefan V.; Smith, Richard D.

2011-01-01

Technologies for separating and characterizing ions based on their transport properties in gases have been around for three decades. The early method of ion mobility spectrometry (IMS) distinguished ions by absolute mobility that depends on the collision cross section with buffer gas atoms. The more recent technique of field asymmetric waveform IMS (FAIMS) measures the difference between mobilities at high and low electric fields. Coupling IMS and FAIMS to soft ionization sources and mass spectrometry (MS) has greatly expanded their utility, enabling new applications in biomedical and nanomaterials research. Here, we show that time-dependent electric fields comprising more than two intensity levels could, in principle, effect an infinite number of distinct differential separations based on the higher-order terms of expression for ion mobility. These analyses could employ the hardware and operational procedures similar to those utilized in FAIMS. Methods up to the 4th or 5th order (where conventional IMS is 1st order and FAIMS is 2nd order) should be practical at field intensities accessible in ambient air, with still higher orders potentially achievable in insulating gases. Available experimental data suggest that higher-order separations should be largely orthogonal to each other and to FAIMS, IMS, and MS. PMID:16494377

Effective potentials in nonlinear polycrystals and quadrature formulae

NASA Astrophysics Data System (ADS)

Michel, Jean-Claude; Suquet, Pierre

2017-08-01

This study presents a family of estimates for effective potentials in nonlinear polycrystals. Noting that these potentials are given as averages, several quadrature formulae are investigated to express these integrals of nonlinear functions of local fields in terms of the moments of these fields. Two of these quadrature formulae reduce to known schemes, including a recent proposition (Ponte Castañeda 2015 Proc. R. Soc. A 471, 20150665 (doi:10.1098/rspa.2015.0665)) obtained by completely different means. Other formulae are also reviewed that make use of statistical information on the fields beyond their first and second moments. These quadrature formulae are applied to the estimation of effective potentials in polycrystals governed by two potentials, by means of a reduced-order model proposed by the authors (non-uniform transformation field analysis). It is shown how the quadrature formulae improve on the tangent second-order approximation in porous crystals at high stress triaxiality. It is found that, in order to retrieve a satisfactory accuracy for highly nonlinear porous crystals under high stress triaxiality, a quadrature formula of higher order is required.

Effective potentials in nonlinear polycrystals and quadrature formulae.

PubMed

Michel, Jean-Claude; Suquet, Pierre

2017-08-01

This study presents a family of estimates for effective potentials in nonlinear polycrystals. Noting that these potentials are given as averages, several quadrature formulae are investigated to express these integrals of nonlinear functions of local fields in terms of the moments of these fields. Two of these quadrature formulae reduce to known schemes, including a recent proposition (Ponte Castañeda 2015 Proc. R. Soc. A 471 , 20150665 (doi:10.1098/rspa.2015.0665)) obtained by completely different means. Other formulae are also reviewed that make use of statistical information on the fields beyond their first and second moments. These quadrature formulae are applied to the estimation of effective potentials in polycrystals governed by two potentials, by means of a reduced-order model proposed by the authors (non-uniform transformation field analysis). It is shown how the quadrature formulae improve on the tangent second-order approximation in porous crystals at high stress triaxiality. It is found that, in order to retrieve a satisfactory accuracy for highly nonlinear porous crystals under high stress triaxiality, a quadrature formula of higher order is required.

Nuclear magnetic resonance signal dynamics of liquids in the presence of distant dipolar fields, revisited

PubMed Central

Barros, Wilson; Gochberg, Daniel F.; Gore, John C.

2009-01-01

The description of the nuclear magnetic resonance magnetization dynamics in the presence of long-range dipolar interactions, which is based upon approximate solutions of Bloch–Torrey equations including the effect of a distant dipolar field, has been revisited. New experiments show that approximate analytic solutions have a broader regime of validity as well as dependencies on pulse-sequence parameters that seem to have been overlooked. In order to explain these experimental results, we developed a new method consisting of calculating the magnetization via an iterative formalism where both diffusion and distant dipolar field contributions are treated as integral operators incorporated into the Bloch–Torrey equations. The solution can be organized as a perturbative series, whereby access to higher order terms allows one to set better boundaries on validity regimes for analytic first-order approximations. Finally, the method legitimizes the use of simple analytic first-order approximations under less demanding experimental conditions, it predicts new pulse-sequence parameter dependencies for the range of validity, and clarifies weak points in previous calculations. PMID:19425789

Study on the mapping of dark matter clustering from real space to redshift space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Yi; Song, Yong-Seon, E-mail: yizheng@kasi.re.kr, E-mail: ysong@kasi.re.kr

The mapping of dark matter clustering from real space to redshift space introduces the anisotropic property to the measured density power spectrum in redshift space, known as the redshift space distortion effect. The mapping formula is intrinsically non-linear, which is complicated by the higher order polynomials due to indefinite cross correlations between the density and velocity fields, and the Finger-of-God effect due to the randomness of the peculiar velocity field. Whilst the full higher order polynomials remain unknown, the other systematics can be controlled consistently within the same order truncation in the expansion of the mapping formula, as shown inmore » this paper. The systematic due to the unknown non-linear density and velocity fields is removed by separately measuring all terms in the expansion directly using simulations. The uncertainty caused by the velocity randomness is controlled by splitting the FoG term into two pieces, 1) the ''one-point' FoG term being independent of the separation vector between two different points, and 2) the ''correlated' FoG term appearing as an indefinite polynomials which is expanded in the same order as all other perturbative polynomials. Using 100 realizations of simulations, we find that the Gaussian FoG function with only one scale-independent free parameter works quite well, and that our new mapping formulation accurately reproduces the observed 2-dimensional density power spectrum in redshift space at the smallest scales by far, up to k ∼ 0.2 Mpc{sup -1}, considering the resolution of future experiments.« less

A Wireless Embedded Sensor based on Magnetic Higher-order Harmonic Fields: Application to Liquid Pressure Monitoring

PubMed Central

Tan, Ee Lim; Pereles, Brandon D.

2010-01-01

A wireless sensor based on the magnetoelastic, magnetically soft ferromagnetic alloy was constructed for remote measurement of pressure in flowing fluids. The pressure sensor was a rectangular strip of ferromagnetic alloy Fe40Ni38Mo4B18 adhered on a solid polycarbonate substrate and protected by a thin polycarbonate film. Upon excitation of a time-varying magnetic field through an excitation coil, the magnetically soft sensor magnetized and produced higher-order harmonic fields, which were detected through a detection coil. Under varying pressures, the sensor's magnetoelastic property caused a change in its magnetization, altering the amplitudes of the higher-order harmonic fields. A theoretical model was developed to describe the effect of pressure on the sensor's higher order harmonic fields. Experimental observations showed the 2nd order harmonic field generated by the pressure sensor was correlated to the surrounding fluid pressure, consistent with the theoretical results. Furthermore, it was demonstrated that the sensor exhibited good repeatability and stability with minimal drift. Sensors with smaller dimensions were shown to have greater sensitivity but lower pressure range as compared to their larger counterparts. Since the sensor signal was also dependent on the location of the sensor with respect to the excitation/detection coil, a calibration algorithm was developed to eliminate signal variations due to the changing sensor location. Because of its wireless and passive nature, this sensor is useful for continuous and long-term monitoring of pressure at inaccessible areas. For example, sensors with these capabilities are suitable to be used in biomedical applications where permanent implantation and long-term monitoring are needed. PMID:20514363

Limitations of the paraxial Debye approximation.

PubMed

Sheppard, Colin J R

2013-04-01

In the paraxial form of the Debye integral for focusing, higher order defocus terms are ignored, which can result in errors in dealing with aberrations, even for low numerical aperture. These errors can be avoided by using a different integration variable. The aberrations of a glass slab, such as a coverslip, are expanded in terms of the new variable, and expressed in terms of Zernike polynomials to assist with aberration balancing. Tube length error is also discussed.

Holographic conductivity of holographic superconductors with higher-order corrections

NASA Astrophysics Data System (ADS)

Sheykhi, Ahmad; Ghazanfari, Afsoon; Dehyadegari, Amin

2018-02-01

We analytically and numerically disclose the effects of the higher-order correction terms in the gravity and in the gauge field on the properties of s-wave holographic superconductors. On the gravity side, we consider the higher curvature Gauss-Bonnet corrections and on the gauge field side, we add a quadratic correction term to the Maxwell Lagrangian. We show that, for this system, one can still obtain an analytical relation between the critical temperature and the charge density. We also calculate the critical exponent and the condensation value both analytically and numerically. We use a variational method, based on the Sturm-Liouville eigenvalue problem for our analytical study, as well as a numerical shooting method in order to compare with our analytical results. For a fixed value of the Gauss-Bonnet parameter, we observe that the critical temperature decreases with increasing the nonlinearity of the gauge field. This implies that the nonlinear correction term to the Maxwell electrodynamics makes the condensation harder. We also study the holographic conductivity of the system and disclose the effects of the Gauss-Bonnet and nonlinear parameters α and b on the superconducting gap. We observe that, for various values of α and b, the real part of the conductivity is proportional to the frequency per temperature, ω /T, as the frequency is large enough. Besides, the conductivity has a minimum in the imaginary part which is shifted toward greater frequency with decreasing temperature.

Higher-order electric multipole contributions to retarded non-additive three-body dispersion interaction energies between atoms: Equilateral triangle and collinear configurations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salam, A., E-mail: salama@wfu.edu

2013-12-28

The theory of molecular quantum electrodynamics (QED) is used to calculate higher electric multipole contributions to the dispersion energy shift between three atoms or molecules arranged in a straight line or in an equilateral triangle configuration. As in two-body potentials, three-body dispersion interactions are viewed in the QED formalism to arise from exchange of virtual photons between coupled pairs of particles. By employing an interaction Hamiltonian that is quadratic in the electric displacement field means that third-order perturbation theory can be used to yield the energy shift for a particular combination of electric multipole polarizable species, with only six time-orderedmore » diagrams needing to be summed over. Specific potentials evaluated include dipole-dipole-quadrupole (DDQ), dipole-quadrupole-quadrupole (DQQ), and dipole-dipole-octupole (DDO) terms. For the geometries of interest, near-zone limiting forms are found to exhibit an R{sup −11} dependence on separation distance for the DDQ interaction, and an R{sup −13} behaviour for DQQ and DDO shifts, agreeing with an earlier semi-classical computation. Retardation weakens the potential in each case by R{sup −1} in the far-zone. It is found that by decomposing the octupole moment into its irreducible components of weights-1 and -3 that the former contribution to the DDO potential may be taken to be a higher-order correction to the leading triple dipole energy shift.« less

Phantom-like behavior of a DGP-inspired Scalar-Gauss-Bonnet gravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nozari, Kourosh; Azizi, Tahereh; Setare, M.R., E-mail: knozari@umz.ac.ir, E-mail: t.azizi@umz.ac.ir, E-mail: rezakord@ipm.ir

2009-10-01

We study the phantom-like behavior of a DGP-inspired braneworld scenario where curvature correction on the brane is taken into account. We include a possible modification of the induced gravity on the brane by incorporating higher order curvature terms of Gauss-Bonnet type. We investigate the cosmological implications of the model and we show that the normal branch of the scenario self-accelerates in this modified scenario without introducing any dark energy component. Also, a phantom-like behavior can be realized in this model without introducing any phantom field that suffers from serious difficulties such as violation of the null energy condition.

A boundary element method for steady incompressible thermoviscous flow

NASA Technical Reports Server (NTRS)

Dargush, G. F.; Banerjee, P. K.

1991-01-01

A boundary element formulation is presented for moderate Reynolds number, steady, incompressible, thermoviscous flows. The governing integral equations are written exclusively in terms of velocities and temperatures, thus eliminating the need for the computation of any gradients. Furthermore, with the introduction of reference velocities and temperatures, volume modeling can often be confined to only a small portion of the problem domain, typically near obstacles or walls. The numerical implementation includes higher order elements, adaptive integration and multiregion capability. Both the integral formulation and implementation are discussed in detail. Several examples illustrate the high level of accuracy that is obtainable with the current method.

Higher order corrections to holographic black hole chemistry

NASA Astrophysics Data System (ADS)

Sinamuli, Musema; Mann, Robert B.

2017-10-01

We investigate the holographic Smarr relation beyond the large N limit. By making use of the holographic dictionary, we find that the bulk correlates of subleading 1 /N corrections to this relation are related to the couplings in Lovelock gravity theories. We likewise obtain a holographic equation of state and check its validity for a variety of interesting and nontrivial black holes, including rotating planar black holes in Gauss-Bonnet-Born-Infeld gravity, and nonextremal rotating black holes in minimal five-dimensional gauged supergravity. We provide an explanation of the N -dependence of the holographic Smarr relation in terms of contributions due to planar and nonplanar diagrams in the dual theory.

A Cross-Cultural Comparison of Singaporean and Taiwanese Eighth Graders' Science Learning Self-Efficacy from a Multi-Dimensional Perspective

NASA Astrophysics Data System (ADS)

Lin, Tzung-Jin; Tan, Aik Ling; Tsai, Chin-Chung

2013-05-01

Due to the scarcity of cross-cultural comparative studies in exploring students' self-efficacy in science learning, this study attempted to develop a multi-dimensional science learning self-efficacy (SLSE) instrument to measure 316 Singaporean and 303 Taiwanese eighth graders' SLSE and further to examine the differences between the two student groups. Moreover, within-culture comparisons were made in terms of gender. The results showed that, first, the SLSE instrument was valid and reliable for measuring the Singaporean and Taiwanese students' SLSE. Second, through a two-way multivariate analysis of variance analysis (nationality by gender), the main result indicated that the SLSE held by the Singaporean eighth graders was significantly higher than that of their Taiwanese counterparts in all dimensions, including 'conceptual understanding and higher-order cognitive skills', 'practical work (PW)', 'everyday application', and 'science communication'. In addition, the within-culture gender comparisons indicated that the male Singaporean students tended to possess higher SLSE than the female students did in all SLSE dimensions except for the 'PW' dimension. However, no gender differences were found in the Taiwanese sample. The findings unraveled in this study were interpreted from a socio-cultural perspective in terms of the curriculum differences, societal expectations of science education, and educational policies in Singapore and Taiwan.

A quantized microwave quadrupole insulator with topologically protected corner states

NASA Astrophysics Data System (ADS)

Peterson, Christopher W.; Benalcazar, Wladimir A.; Hughes, Taylor L.; Bahl, Gaurav

2018-03-01

The theory of electric polarization in crystals defines the dipole moment of an insulator in terms of a Berry phase (geometric phase) associated with its electronic ground state. This concept not only solves the long-standing puzzle of how to calculate dipole moments in crystals, but also explains topological band structures in insulators and superconductors, including the quantum anomalous Hall insulator and the quantum spin Hall insulator, as well as quantized adiabatic pumping processes. A recent theoretical study has extended the Berry phase framework to also account for higher electric multipole moments, revealing the existence of higher-order topological phases that have not previously been observed. Here we demonstrate experimentally a member of this predicted class of materials—a quantized quadrupole topological insulator—produced using a gigahertz-frequency reconfigurable microwave circuit. We confirm the non-trivial topological phase using spectroscopic measurements and by identifying corner states that result from the bulk topology. In addition, we test the critical prediction that these corner states are protected by the topology of the bulk, and are not due to surface artefacts, by deforming the edges of the crystal lattice from the topological to the trivial regime. Our results provide conclusive evidence of a unique form of robustness against disorder and deformation, which is characteristic of higher-order topological insulators.

Influence of the flap on outcomes in corneal refractive surgery with femtosecond laser: SMILE vs. FLEx.

PubMed

Alió, J L; El Bahrawy, M; Angelov, A; Ortiz, D; Yébana, P

2017-05-01

To investigate the influence of creating a flap on the postoperative optical quality of the cornea in terms of predicted corneal curvature and Seidel aberrations after 2 modalities of femtosecond assisted corneal lenticule extraction laser for the correction of myopia and myopic astigmatism: The flapless procedure small incision lenticular extraction (SMILE) and the flap-based femtosecond lenticular extraction (FLEx). The study is a prospective consecutive non-randomised comparative interventional case series including 64 eyes with myopic or myopic astigmatism refractive errors. Patients were divided into 2 groups matched for age, sex and myopia. One group underwent SMILE treatment and the other underwent FLEx treatment. Seidel aberrations root-mean-square values were obtained with a 10mm aperture using the ATLAS 9000 topographer before surgery and 3 months after surgery. The relationship between the post-surgical corneal radius and the predicted sculpted radius were analysed in each group. The mean percentage change in the curvature radius was -2.03% in the FLEx group and -1.77% in the SMILE group (P=.655). The higher correlation for the SMILE group demonstrates a better predictability after the surgery. As regards corneal aberrations, the FLEx treatment showed a greater increase of higher order aberrations than SMILE treatment (P=.04). The mean refractive change in corneal curvature, which is indirectly related to the biomechanical response of the corneal surface after the lenticule cut and extraction, was similar after both treatments. However, the flap based FLEx procedure showed a greater degradation of the corneal optical quality in terms of induction of higher order aberrations. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Baryon masses and σ terms in SU(3) BChPT × 1/Nc

NASA Astrophysics Data System (ADS)

Fernando, I. P.; Alarcón, J. M.; Goity, J. L.

2018-06-01

Baryon masses and nucleon σ terms are studied with the effective theory that combines the chiral and 1 /Nc expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the σ term associated with the scalar density u bar u + d bar d - 2 s bar s is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a σ term puzzle. It is shown that while the nucleon σ terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Adding to the analysis lattice QCD baryon masses, it is found that σπN = 69 (10) MeV and σs has natural magnitude within its relatively large uncertainty.

Baryon masses and σ terms in SU(3) BChPT×1/N c

DOE PAGES

Fernando, Ishara P.; Alarcon-Soriano, Jose-Manuel; Goity, Jose Luis

2018-04-27

Baryon masses and nucleonmore » $$\\sigma$$ terms are studied with the effective theory that combines the chiral and $$1/N_c$$ expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the $$\\sigma$$ term associated with the scalar density $$\\bar u u+\\bar d d-2\\bar s s$$ is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a $$\\sigma$$ term puzzle. It is shown that while the nucleon $$\\sigma$$ terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Lastly, adding to the analysis lattice QCD baryon masses, it is found that $$\\sigma_{\\pi N}=69(10)$$~MeV and $$\\sigma_s$$ has natural magnitude within its relative large uncertainty.« less

Baryon masses and σ terms in SU(3) BChPT×1/N c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernando, Ishara P.; Alarcon-Soriano, Jose-Manuel; Goity, Jose Luis

Baryon masses and nucleonmore » $$\\sigma$$ terms are studied with the effective theory that combines the chiral and $$1/N_c$$ expansions for three flavors. In particular the connection between the deviation of the Gell-Mann-Okubo relation and the $$\\sigma$$ term associated with the scalar density $$\\bar u u+\\bar d d-2\\bar s s$$ is emphasized. The latter is at lowest order related to a mass combination whose low value has given rise to a $$\\sigma$$ term puzzle. It is shown that while the nucleon $$\\sigma$$ terms have a well behaved low energy expansion, that mass combination is affected by large higher order corrections non-analytic in quark masses. Lastly, adding to the analysis lattice QCD baryon masses, it is found that $$\\sigma_{\\pi N}=69(10)$$~MeV and $$\\sigma_s$$ has natural magnitude within its relative large uncertainty.« less

Epigenomics.

PubMed

Gomase, Virendra S; Tagore, Somnath

2008-03-01

'Epigenomics' can be termed as the study of the effects of chromatin structure, including the higher order of chromatin folding and attachment to the nuclear matrix, packaging of DNA around nucleosomes, covalent modifications of histone tails and DNA methylation. This has evolved to include any process that alters gene activity without changing the DNA sequence, and leads to modifications that can be transmitted to daughter cells. It also leads to a better knowledge of the changes in the regulation of genes and genomes that occur in major psychosis. It may also aid in understanding why the same gene sequence may predispose an individual to schizophrenia or bipolar disorder and in other cases does not, and elucidate the molecular mechanisms of how harmful; environmental factors interact with the genome. Results from the work may further lead to new diagnostics and effective therapies.

Multicritical scalar theories with higher-derivative kinetic terms: A perturbative RG approach with the ɛ -expansion

NASA Astrophysics Data System (ADS)

Safari, M.; Vacca, G. P.

2018-02-01

We employ perturbative renormalization group and ɛ -expansion to study multicritical single-scalar field theories with higher derivative kinetic terms of the form ϕ (-□)kϕ . We focus on those with a Z2-symmetric critical point which are characterized by an upper critical dimension dc=2 n k /(n -1 ) accumulating at even integers. We distinguish two types of theories depending on whether or not the numbers k and n -1 are relatively prime. When they are, the critical theory involves a marginal powerlike interaction ϕ2 n and the deformations admit a derivative expansion that at leading order involves only the potential. In this case we present the beta functional of the potential and use this to calculate some anomalous dimensions and operator product expansion coefficients. These confirm some conformal field theory data obtained using conformal-block techniques, while giving new results. In the second case where k and n -1 have a common divisor, the theories show a much richer structure induced by the presence of marginal derivative operators at criticality. We study the case k =2 with odd values of n , which fall in the second class, and calculate the functional flows and spectrum. These theories have a phase diagram characterized at leading order in ɛ by four fixed points which apart from the Gaussian UV fixed point include an IR fixed point with a purely derivative interaction.

Rogue-wave solutions of the Zakharov equation

NASA Astrophysics Data System (ADS)

Rao, Jiguang; Wang, Lihong; Liu, Wei; He, Jingsong

2017-12-01

Using the bilinear transformation method, we derive general rogue-wave solutions of the Zakharov equation. We present these Nth-order rogue-wave solutions explicitly in terms of Nth-order determinants whose matrix elements have simple expressions. We show that the fundamental rogue wave is a line rogue wave with a line profile on the plane ( x, y) arising from a constant background at t ≪ 0 and then gradually tending to the constant background for t ≫ 0. Higher-order rogue waves arising from a constant background and later disappearing into it describe the interaction of several fundamental line rogue waves. We also consider different structures of higher-order rogue waves. We present differences between rogue waves of the Zakharov equation and of the first type of the Davey-Stewartson equation analytically and graphically.

Integrability and solitons for the higher-order nonlinear Schrödinger equation with space-dependent coefficients in an optical fiber

NASA Astrophysics Data System (ADS)

Su, Jing-Jing; Gao, Yi-Tian

2018-03-01

Under investigation in this paper is a higher-order nonlinear Schrödinger equation with space-dependent coefficients, related to an optical fiber. Based on the self-similarity transformation and Hirota method, related to the integrability, the N-th-order bright and dark soliton solutions are derived under certain constraints. It is revealed that the velocities and trajectories of the solitons are both affected by the coefficient of the sixth-order dispersion term while the amplitudes of the solitons are determined by the gain function. Amplitudes increase when the gain function is positive and decrease when the gain function is negative. Furthermore, we find that the intensities of dark solitons are presented as a superposition of the solitons and stationary waves.

Antiferromagnetism, charge density wave, and d-wave superconductivity in the extended t-J-U model: role of intersite Coulomb interaction and a critical overview of renormalized mean field theory.

PubMed

Abram, M; Zegrodnik, M; Spałek, J

2017-09-13

In the first part of the paper, we study the stability of antiferromagnetic (AF), charge density wave (CDW), and superconducting (SC) states within the t-J-U-V model of strongly correlated electrons by using the statistically consistent Gutzwiller approximation (SGA). We concentrate on the role of the intersite Coulomb interaction term V in stabilizing the CDW phase. In particular, we show that the charge ordering appears only above a critical value of V in a limited hole-doping range δ. The effect of the V term on SC and AF phases is that a strong interaction suppresses SC, whereas the AF order is not significantly influenced by its presence. In the second part, separate calculations for the case of a pure SC phase have been carried out within an extended approach (the diagrammatic expansion for the Gutzwiller wave function, DE-GWF) in order to analyze the influence of the intersite Coulomb repulsion on the SC phase with the higher-order corrections included beyond the SGA method. The upper concentration for the SC disappearance decreases with increasing V, bringing the results closer to experiment. In appendices A and B we discuss the ambiguity connected with the choice of the Gutzwiller renormalization factors within the renormalized mean filed theory when either AF or CDW orders are considered. At the end, we overview briefly the possible extensions of the current models to put descriptions of the SC, AF, and CDW states on equal footing.

Second order kinetic theory of parallel momentum transport in collisionless drift wave turbulence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yang, E-mail: lyang13@mails.tsinghua.edu.cn; Southwestern Institute of Physics, Chengdu 610041; Gao, Zhe

A second order kinetic model for turbulent ion parallel momentum transport is presented. A new nonresonant second order parallel momentum flux term is calculated. The resonant component of the ion parallel electrostatic force is the momentum source, while the nonresonant component of the ion parallel electrostatic force compensates for that of the nonresonant second order parallel momentum flux. The resonant component of the kinetic momentum flux can be divided into three parts, including the pinch term, the diffusive term, and the residual stress. By reassembling the pinch term and the residual stress, the residual stress can be considered as amore » pinch term of parallel wave-particle resonant velocity, and, therefore, may be called as “resonant velocity pinch” term. Considering the resonant component of the ion parallel electrostatic force is the transfer rate between resonant ions and waves (or, equivalently, nonresonant ions), a conservation equation of the parallel momentum of resonant ions and waves is obtained.« less

A Critique on the Concept of Social Accountability in Higher Education

ERIC Educational Resources Information Center

Pedroza Flores, René; Villalobos Monroy, Guadalupe; Reyes Fabela, Ana María

2015-01-01

This paper attempts to present a critique of the concept and meaning of the term social accountability at university level from a critical point of view. The main objective is to analyze and re-build the term accountability in order to contextualize it for public universities. First, we present the importance of the idea of accountability in…

Germinating a New SEAD: The Implications of Executing the SEAD Mission in a UCAV

DTIC Science & Technology

2001-06-01

20 SEAD FROM BIRTH TO MATURITY...reader must understand those differences in order to understand the weight in the argument. The first group of related terms has to do with unmanned...higher flying were ordered in mass numbers. However, these RPVs were strictly for target practice. None was intended for combat.12 At the onset

Cosmological collapse and the improved Zel'dovich approximation.

NASA Astrophysics Data System (ADS)

Salopek, D. S.; Stewart, J. M.; Croudace, K. M.; Parry, J.

Using a general relativistic formulation, the authors show how to compute the higher order terms in the Zel'dovich approximation which describes cosmological collapse. They evolve the 3-metric in a spatial gradient expansion. Their method is an advance over earlier work because it is local at each order. Using the improved Zel'dovich approximation, they compute the epoch of collapse.

Averaging Principle for the Higher Order Nonlinear Schrödinger Equation with a Random Fast Oscillation

NASA Astrophysics Data System (ADS)

Gao, Peng

2018-06-01

This work concerns the problem associated with averaging principle for a higher order nonlinear Schrödinger equation perturbed by a oscillating term arising as the solution of a stochastic reaction-diffusion equation evolving with respect to the fast time. This model can be translated into a multiscale stochastic partial differential equations. Stochastic averaging principle is a powerful tool for studying qualitative analysis of stochastic dynamical systems with different time-scales. To be more precise, under suitable conditions, we prove that there is a limit process in which the fast varying process is averaged out and the limit process which takes the form of the higher order nonlinear Schrödinger equation is an average with respect to the stationary measure of the fast varying process. Finally, by using the Khasminskii technique we can obtain the rate of strong convergence for the slow component towards the solution of the averaged equation, and as a consequence, the system can be reduced to a single higher order nonlinear Schrödinger equation with a modified coefficient.

Averaging Principle for the Higher Order Nonlinear Schrödinger Equation with a Random Fast Oscillation

NASA Astrophysics Data System (ADS)

Gao, Peng

2018-04-01

This work concerns the problem associated with averaging principle for a higher order nonlinear Schrödinger equation perturbed by a oscillating term arising as the solution of a stochastic reaction-diffusion equation evolving with respect to the fast time. This model can be translated into a multiscale stochastic partial differential equations. Stochastic averaging principle is a powerful tool for studying qualitative analysis of stochastic dynamical systems with different time-scales. To be more precise, under suitable conditions, we prove that there is a limit process in which the fast varying process is averaged out and the limit process which takes the form of the higher order nonlinear Schrödinger equation is an average with respect to the stationary measure of the fast varying process. Finally, by using the Khasminskii technique we can obtain the rate of strong convergence for the slow component towards the solution of the averaged equation, and as a consequence, the system can be reduced to a single higher order nonlinear Schrödinger equation with a modified coefficient.

Pulse transmission receiver with higher-order time derivative pulse correlator

DOEpatents

Dress, Jr., William B.; Smith, Stephen F.

2003-09-16

Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a higher-order time derivative pulse correlator; a demodulation decoder coupled to the higher-order time derivative pulse correlator; a clock coupled to the demodulation decoder; and a pseudorandom polynomial generator coupled to both the higher-order time derivative pulse correlator and the clock. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

75 FR 38516 - Order on Intent To Revoke Market-Based Rate Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-02

..., Electric Quarterly Reports, Strategic Energy Management Corp., Solaro Energy Marketing Corporation. 1... (including market-based power sales, cost-based power sales, and transmission service) and providing transaction information (including rates) for short-term and long-term power sales during the most recent...

Principles of chronic venous access: recommendations based on the Roswell Park experience.

PubMed

Sabel, M S; Smith, J L

1997-11-01

At Roswell Park Cancer Institute, we have seen a dramatic increase in the need for long-term venous access. Chronic venous catheters are an indispensible part of the treatment provided to oncology patients. Cancer patients are often at higher risk for complications secondary to their underlying disease and treatments. These risks may be minimized by paying close attention to several important aspects of central line placement. These include matching individual patient needs with the access device most suited to those needs, a thorough preoperative assessment, and the safest and most appropriate operative approach for placement. Likewise, the prompt recognition and treatment of complications when they do occur is crucial to the care of these patients. In order to optimize the care of patients with long-term venous access devices, we have reviewed our experience of over 700 vascular access consultations and offer the following recommendations.

From Physics Model to Results: An Optimizing Framework for Cross-Architecture Code Generation

DOE PAGES

Blazewicz, Marek; Hinder, Ian; Koppelman, David M.; ...

2013-01-01

Starting from a high-level problem description in terms of partial differential equations using abstract tensor notation, the Chemora framework discretizes, optimizes, and generates complete high performance codes for a wide range of compute architectures. Chemora extends the capabilities of Cactus, facilitating the usage of large-scale CPU/GPU systems in an efficient manner for complex applications, without low-level code tuning. Chemora achieves parallelism through MPI and multi-threading, combining OpenMP and CUDA. Optimizations include high-level code transformations, efficient loop traversal strategies, dynamically selected data and instruction cache usage strategies, and JIT compilation of GPU code tailored to the problem characteristics. The discretization ismore » based on higher-order finite differences on multi-block domains. Chemora's capabilities are demonstrated by simulations of black hole collisions. This problem provides an acid test of the framework, as the Einstein equations contain hundreds of variables and thousands of terms.« less

von Kármán–Howarth Equation for Hall Magnetohydrodynamics: Hybrid Simulations

NASA Astrophysics Data System (ADS)

Hellinger, Petr; Verdini, Andrea; Landi, Simone; Franci, Luca; Matteini, Lorenzo

2018-04-01

A dynamical vectorial equation for homogeneous incompressible Hall-magnetohydrodynamic (MHD) turbulence together with the exact scaling law for third-order correlation tensors, analogous to that for the incompressible MHD, is rederived and applied to the results of two-dimensional hybrid simulations of plasma turbulence. At large (MHD) scales the simulations exhibit a clear inertial range where the MHD dynamic law is valid. In the sub-ion range the cascade continues via the Hall term, but the dynamic law derived in the framework of incompressible Hall-MHD equations is obtained only in a low plasma beta simulation. For a higher beta plasma the cascade rate decreases in the sub-ion range and the change becomes more pronounced as the plasma beta increases. This break in the cascade flux can be ascribed to nonthermal (kinetic) features or to others terms in the dynamical equation that are not included in the Hall-MHD incompressible approximation.

Black hole hair formation in shift-symmetric generalised scalar-tensor gravity

NASA Astrophysics Data System (ADS)

Benkel, Robert; Sotiriou, Thomas P.; Witek, Helvi

2017-03-01

A linear coupling between a scalar field and the Gauss-Bonnet invariant is the only known interaction term between a scalar and the metric that: respects shift symmetry; does not lead to higher order equations; inevitably introduces black hole hair in asymptotically flat, 4-dimensional spacetimes. Here we focus on the simplest theory that includes such a term and we explore the dynamical formation of scalar hair. In particular, we work in the decoupling limit that neglects the backreaction of the scalar onto the metric and evolve the scalar configuration numerically in the background of a Schwarzschild black hole and a collapsing dust star described by the Oppenheimer-Snyder solution. For all types of initial data that we consider, the scalar relaxes at late times to the known, static, analytic configuration that is associated with a hairy, spherically symmetric black hole. This suggests that the corresponding black hole solutions are indeed endpoints of collapse.

Increasing Accuracy in Computed Inviscid Boundary Conditions

NASA Technical Reports Server (NTRS)

Dyson, Roger

2004-01-01

A technique has been devised to increase the accuracy of computational simulations of flows of inviscid fluids by increasing the accuracy with which surface boundary conditions are represented. This technique is expected to be especially beneficial for computational aeroacoustics, wherein it enables proper accounting, not only for acoustic waves, but also for vorticity and entropy waves, at surfaces. Heretofore, inviscid nonlinear surface boundary conditions have been limited to third-order accuracy in time for stationary surfaces and to first-order accuracy in time for moving surfaces. For steady-state calculations, it may be possible to achieve higher accuracy in space, but high accuracy in time is needed for efficient simulation of multiscale unsteady flow phenomena. The present technique is the first surface treatment that provides the needed high accuracy through proper accounting of higher-order time derivatives. The present technique is founded on a method known in art as the Hermitian modified solution approximation (MESA) scheme. This is because high time accuracy at a surface depends upon, among other things, correction of the spatial cross-derivatives of flow variables, and many of these cross-derivatives are included explicitly on the computational grid in the MESA scheme. (Alternatively, a related method other than the MESA scheme could be used, as long as the method involves consistent application of the effects of the cross-derivatives.) While the mathematical derivation of the present technique is too lengthy and complex to fit within the space available for this article, the technique itself can be characterized in relatively simple terms: The technique involves correction of surface-normal spatial pressure derivatives at a boundary surface to satisfy the governing equations and the boundary conditions and thereby achieve arbitrarily high orders of time accuracy in special cases. The boundary conditions can now include a potentially infinite number of time derivatives of surface-normal velocity (consistent with no flow through the boundary) up to arbitrarily high order. The corrections for the first-order spatial derivatives of pressure are calculated by use of the first-order time derivative velocity. The corrected first-order spatial derivatives are used to calculate the second- order time derivatives of velocity, which, in turn, are used to calculate the corrections for the second-order pressure derivatives. The process as described is repeated, progressing through increasing orders of derivatives, until the desired accuracy is attained.

Regularizing the r-mode Problem for Nonbarotropic Relativistic Stars

NASA Technical Reports Server (NTRS)

Lockitch, Keith H.; Andersson, Nils; Watts, Anna L.

2004-01-01

We present results for r-modes of relativistic nonbarotropic stars. We show that the main differential equation, which is formally singular at lowest order in the slow-rotation expansion, can be regularized if one considers the initial value problem rather than the normal mode problem. However, a more physically motivated way to regularize the problem is to include higher order terms. This allows us to develop a practical approach for solving the problem and we provide results that support earlier conclusions obtained for uniform density stars. In particular, we show that there will exist a single r-mode for each permissible combination of 1 and m. We discuss these results and provide some caveats regarding their usefulness for estimates of gravitational-radiation reaction timescales. The close connection between the seemingly singular relativistic r-mode problem and issues arising because of the presence of co-rotation points in differentially rotating stars is also clarified.

NASA astrophysics - Optical systems to explore the universe

NASA Technical Reports Server (NTRS)

Pellerin, C. J., Jr.; Stencel, R. E.

1983-01-01

Major and minor NASA astrophysical research efforts in the near-term are outlined, together with projections of direction for future projects. The Space Telescope is being readied for a 1986 launch and will feature an f/24, 2.4 m aperture, an MgF2 mirror with better than 1/60 wavelength accuracy and will be diffraction-limited in the UV. Pointing accuracy is designed to be 0.007 arcsec for 24 hr. Optical, spectrometric, and photometric equipment will be included. Around 1990, Shuttle-based missions will include an IR telescope and a subarcsec solar surface imaging device. A free-flying X-ray observatory (AXAF) is planned and will include a sensitivity that exceeds that of the HEAO-2 spacecraft by two orders of magnitude. Instruments are under development for higher resolution UV, gamma-ray, and IR studies. In-orbit interferometry is being studied and will depend on in-orbit assembly and servicing of stable structures with segmented optics.

Conformal superalgebras via tractor calculus

NASA Astrophysics Data System (ADS)

Lischewski, Andree

2015-01-01

We use the manifestly conformally invariant description of a Lorentzian conformal structure in terms of a parabolic Cartan geometry in order to introduce a superalgebra structure on the space of twistor spinors and normal conformal vector fields formulated in purely algebraic terms on parallel sections in tractor bundles. Via a fixed metric in the conformal class, one reproduces a conformal superalgebra structure that has been considered in the literature before. The tractor approach, however, makes clear that the failure of this object to be a Lie superalgebra in certain cases is due to purely algebraic identities on the spinor module and to special properties of the conformal holonomy representation. Moreover, it naturally generalizes to higher signatures. This yields new formulas for constructing new twistor spinors and higher order normal conformal Killing forms out of existing ones, generalizing the well-known spinorial Lie derivative. Moreover, we derive restrictions on the possible dimension of the space of twistor spinors in any metric signature.

Evaluation of the Teaching Standards at Institutions of Higher Education Looks Forward to "Five Changes"

ERIC Educational Resources Information Center

Zhentian, Liu

2009-01-01

In order to promote the sustained and healthy development of teaching evaluation work, five changes should be brought about in the evaluation of the level of undergraduate teaching at China's institutions of higher education: Change teaching evaluation from a specific item of work to a system of a long-term and normative nature; change teaching…

Developing Critical Thinking Skills in Students: A Mandate for Higher Education in Nigeria

ERIC Educational Resources Information Center

Adeyemi, Sunday Bankole

2012-01-01

This paper is conceptualized to examine ways by which higher education in our own country (Nigeria) could be re-organized in such a manner that critical thinking skills could be imbued in the young learners, in order to make them problem solvers, thereby become assets rather than liabilities to the Nigerian society. In specific terms, the paper…

FRW and domain walls in higher spin gravity

NASA Astrophysics Data System (ADS)

Aros, R.; Iazeolla, C.; Noreña, J.; Sezgin, E.; Sundell, P.; Yin, Y.

2018-03-01

We present exact solutions to Vasiliev's bosonic higher spin gravity equations in four dimensions with positive and negative cosmological constant that admit an interpretation in terms of domain walls, quasi-instantons and Friedman-Robertson-Walker (FRW) backgrounds. Their isometry algebras are infinite dimensional higher-spin extensions of spacetime isometries generated by six Killing vectors. The solutions presented are obtained by using a method of holomorphic factorization in noncommutative twistor space and gauge functions. In interpreting the solutions in terms of Fronsdal-type fields in space-time, a field-dependent higher spin transformation is required, which is implemented at leading order. To this order, the scalar field solves Klein-Gordon equation with conformal mass in ( A) dS 4 . We interpret the FRW solution with de Sitter asymptotics in the context of inflationary cosmology and we expect that the domain wall and FRW solutions are associated with spontaneously broken scaling symmetries in their holographic description. We observe that the factorization method provides a convenient framework for setting up a perturbation theory around the exact solutions, and we propose that the nonlinear completion of particle excitations over FRW and domain wall solutions requires black hole-like states.

Black holes in higher derivative gravity.

PubMed

Lü, H; Perkins, A; Pope, C N; Stelle, K S

2015-05-01

Extensions of Einstein gravity with higher-order derivative terms arise in string theory and other effective theories, as well as being of interest in their own right. In this Letter we study static black-hole solutions in the example of Einstein gravity with additional quadratic curvature terms. A Lichnerowicz-type theorem simplifies the analysis by establishing that they must have vanishing Ricci scalar curvature. By numerical methods we then demonstrate the existence of further black-hole solutions over and above the Schwarzschild solution. We discuss some of their thermodynamic properties, and show that they obey the first law of thermodynamics.

Pain coping strategies: Neonatal intensive care unit survivors in adolescence.

PubMed

van Ganzewinkel, Christ-Jan; Been, Jasper V; Dieleman, Jeanne P; Katgert, Titia; Boelen-van der Loo, Tera; van der Pal, Sylvia M; van Dijk, Monique; Kramer, Boris W; Andriessen, Peter

2016-12-01

Data on long-term consequences of preterm birth on pain coping later in life are limited. To assess whether gestational age, birth weight and neonatal disease severity have effect on pain coping style in adolescents born preterm or with low birth weight. Observational, longitudinal study (Project On Preterm and SGA-infants, POPS-19). We analyzed data of 537 adolescents at the age of 19 years, who were born at a gestational age <32 weeks or with a birth weight <1500g. Participants completed the pain coping questionnaire (PCQ) that assesses pain coping strategies in three higher-order factors: approach ("to deal with pain"), problem-focused avoidance ("to disengage from pain") and emotion-focused avoidance ("expression of pain"). Furthermore, their pain coping effectiveness, pain controllability and emotional reactions to pain were assessed. All participants completed an IQ test. Univariate analysis showed no significant correlation between length of stay, sepsis and necrotizing enterocolitis and any of the higher-order factors. Approach was only correlated with IQ. Problem-focused avoidance was, in the multiple regression analysis (including gestational age, IVH and IQ), only correlated with IQ. For emotion-focused avoidance (including birth weight, SGA, IVH, respiratory support and IQ) three independent predictors remained: IVH was positively correlated, while respiratory support and IQ were negatively correlated with emotion-focused avoidance. Early neonatal characteristics and neonatal disease severity have limited effect on pain coping style in adolescence. Higher IQ was associated with the use of adaptive coping strategies, while maladaptive strategies were used less. Copyright © 2016. Published by Elsevier Ireland Ltd.

Higher-order vector discrete rogue-wave states in the coupled Ablowitz-Ladik equations: Exact solutions and stability.

PubMed

Wen, Xiao-Yong; Yan, Zhenya; Malomed, Boris A

2016-12-01

An integrable system of two-component nonlinear Ablowitz-Ladik equations is used to construct complex rogue-wave (RW) solutions in an explicit form. First, the modulational instability of continuous waves is studied in the system. Then, new higher-order discrete two-component RW solutions of the system are found by means of a newly derived discrete version of a generalized Darboux transformation. Finally, the perturbed evolution of these RW states is explored in terms of systematic simulations, which demonstrates that tightly and loosely bound RWs are, respectively, nearly stable and strongly unstable solutions.

Umbilical-spinous line: a morphological term that should be included in the anatomical terminology

PubMed Central

Ríos, John

2013-01-01

We argue the need to include in the International Anatomical Terminology the term "Umbilical-spinous line" for its importance as a morphological referent in bioscopic and surface anatomy. Also, in order to avoid using eponyms, it is suggested that the traditional term "McBurney point" be replaced by "supra spinous point" as being more descriptive of location. PMID:24892620

A molecular theory of smectic C liquid crystals made of rod-like molecules.

PubMed

Govind, A S; Madhusudana, N V

2002-10-01

Organic compounds exhibiting the smectic C phase are made of rod-like molecules that have dipolar groups with lateral components. We argue that the off-axis character of the lateral dipolar groups can account for tilt in layered smectics (SmC, SmC*, SmI etc.). We develop a mean-field theory of the smectic C phase based on a single-particle potential of the form UC is proportional to sin(2theta) cos phi, consistent with the biaxial nature of the phase, where theta and phi are the polar and azimuthal angles, respectively. The hard-rod interactions that favour the smectic A phase with zero tilt angle are also included. The theoretical phase diagrams compare favourably with experimental trends. Our theory also leads to the following results: i) a first-order smectic C to smectic A transition above some value of the McMillan parameter alpha, leading to a tricritical point on the smectic C to smectic A transition line and ii) a first-order smectic C to smectic C transition over a very small range of values of the model parameters. We have also extended the theory to include the next higher-order term in the tilting potential and to include the effect of different tilt angles for the molecular core and the chain in the SmC phase.

Diagrammatic Monte Carlo approach for diagrammatic extensions of dynamical mean-field theory: Convergence analysis of the dual fermion technique

NASA Astrophysics Data System (ADS)

Gukelberger, Jan; Kozik, Evgeny; Hafermann, Hartmut

2017-07-01

The dual fermion approach provides a formally exact prescription for calculating properties of a correlated electron system in terms of a diagrammatic expansion around dynamical mean-field theory (DMFT). Most practical implementations, however, neglect higher-order interaction vertices beyond two-particle scattering in the dual effective action and further truncate the diagrammatic expansion in the two-particle scattering vertex to a leading-order or ladder-type approximation. In this work, we compute the dual fermion expansion for the two-dimensional Hubbard model including all diagram topologies with two-particle interactions to high orders by means of a stochastic diagrammatic Monte Carlo algorithm. We benchmark the obtained self-energy against numerically exact diagrammatic determinant Monte Carlo simulations to systematically assess convergence of the dual fermion series and the validity of these approximations. We observe that, from high temperatures down to the vicinity of the DMFT Néel transition, the dual fermion series converges very quickly to the exact solution in the whole range of Hubbard interactions considered (4 ≤U /t ≤12 ), implying that contributions from higher-order vertices are small. As the temperature is lowered further, we observe slower series convergence, convergence to incorrect solutions, and ultimately divergence. This happens in a regime where magnetic correlations become significant. We find, however, that the self-consistent particle-hole ladder approximation yields reasonable and often even highly accurate results in this regime.

Improving fluid intelligence with training on working memory: a meta-analysis.

PubMed

Au, Jacky; Sheehan, Ellen; Tsai, Nancy; Duncan, Greg J; Buschkuehl, Martin; Jaeggi, Susanne M

2015-04-01

Working memory (WM), the ability to store and manipulate information for short periods of time, is an important predictor of scholastic aptitude and a critical bottleneck underlying higher-order cognitive processes, including controlled attention and reasoning. Recent interventions targeting WM have suggested plasticity of the WM system by demonstrating improvements in both trained and untrained WM tasks. However, evidence on transfer of improved WM into more general cognitive domains such as fluid intelligence (Gf) has been more equivocal. Therefore, we conducted a meta-analysis focusing on one specific training program, n-back. We searched PubMed and Google Scholar for all n-back training studies with Gf outcome measures, a control group, and healthy participants between 18 and 50 years of age. In total, we included 20 studies in our analyses that met our criteria and found a small but significant positive effect of n-back training on improving Gf. Several factors that moderate this transfer are identified and discussed. We conclude that short-term cognitive training on the order of weeks can result in beneficial effects in important cognitive functions as measured by laboratory tests.

Response spectrum method for extreme wave loading with higher order components of drag force

NASA Astrophysics Data System (ADS)

Reza, Tabeshpour Mohammad; Mani, Fatemi Dezfouli; Ali, Dastan Diznab Mohammad; Saied, Mohajernasab; Saied, Seif Mohammad

2017-03-01

Response spectra of fixed offshore structures impacted by extreme waves are investigated based on the higher order components of the nonlinear drag force. In this way, steel jacket platforms are simplified as a mass attached to a light cantilever cylinder and their corresponding deformation response spectra are estimated by utilizing a generalized single degree of freedom system. Based on the wave data recorded in the Persian Gulf region, extreme wave loading conditions corresponding to different return periods are exerted on the offshore structures. Accordingly, the effect of the higher order components of the drag force is considered and compared to the linearized state for different sea surface levels. When the fundamental period of the offshore structure is about one third of the main period of wave loading, the results indicate the linearized drag term is not capable of achieving a reliable deformation response spectrum.

Higher-order dielectrophoretic effects: levitation at a field null.

PubMed

Washizu, M; Jones, T B; Kaler, K V

1993-08-20

Experiments with certain new micro-electrode structures used to achieve passive dielectrophoretic levitation of small particles and biological cells reveal a pronounced size-dependent effect not anticipated by the conventional dipole-based model. The conventional theory fails to predict this size effect because it neglects higher-order moments such as the quadrupole, hexapole, and octupole. These higher-order moments are in fact responsible for the levitation force achieved by azimuthally periodic electrode structures because, in such geometries, the electric field is zero along the axis so that the induced dipole moment must be zero. For example, the planar quadrupole levitates particles passively along the central axis through the interaction of its field with the induced quadrupolar moment of the particle. The size effect reported with this structure is readily explained in terms of this quadrupolar component of the ponderomotive force exerted on the particle.

Statistical analysis of excitation energies in actinide and rare-earth nuclei

NASA Astrophysics Data System (ADS)

Levon, A. I.; Magner, A. G.; Radionov, S. V.

2018-04-01

Statistical analysis of distributions of the collective states in actinide and rare-earth nuclei is performed in terms of the nearest-neighbor spacing distribution (NNSD). Several approximations, such as the linear approach to the level repulsion density and that suggested by Brody to the NNSDs were applied for the analysis. We found an intermediate character of the experimental spectra between the order and the chaos for a number of rare-earth and actinide nuclei. The spectra are closer to the Wigner distribution for energies limited by 3 MeV, and to the Poisson distribution for data including higher excitation energies and higher spins. The latter result is in agreement with the theoretical calculations. These features are confirmed by the cumulative distributions, where the Wigner contribution dominates at smaller spacings while the Poisson one is more important at larger spacings, and our linear approach improves the comparison with experimental data at all desired spacings.

Conformal killing tensors and covariant Hamiltonian dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cariglia, M., E-mail: marco@iceb.ufop.br; Gibbons, G. W., E-mail: G.W.Gibbons@damtp.cam.ac.uk; LE STUDIUM, Loire Valley Institute for Advanced Studies, Tours and Orleans

2014-12-15

A covariant algorithm for deriving the conserved quantities for natural Hamiltonian systems is combined with the non-relativistic framework of Eisenhart, and of Duval, in which the classical trajectories arise as geodesics in a higher dimensional space-time, realized by Brinkmann manifolds. Conserved quantities which are polynomial in the momenta can be built using time-dependent conformal Killing tensors with flux. The latter are associated with terms proportional to the Hamiltonian in the lower dimensional theory and with spectrum generating algebras for higher dimensional quantities of order 1 and 2 in the momenta. Illustrations of the general theory include the Runge-Lenz vector formore » planetary motion with a time-dependent gravitational constant G(t), motion in a time-dependent electromagnetic field of a certain form, quantum dots, the Hénon-Heiles and Holt systems, respectively, providing us with Killing tensors of rank that ranges from one to six.« less

Filtering higher-order laser modes using leaky plasma channels

NASA Astrophysics Data System (ADS)

Djordjević, B. Z.; Benedetti, C.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.

2018-01-01

Plasma structures based on leaky channels are proposed to filter higher-order laser mode content. The evolution and propagation of non-Gaussian laser pulses in leaky channels are studied, and it is shown that, for appropriate laser-plasma parameters, the higher-order laser mode content of the pulse may be removed while the fundamental mode remains well-guided. The behavior of multi-mode laser pulses is described analytically and numerically using envelope equations, including the derivation of the leakage coefficients, and compared to particle-in-cell simulations. Laser pulse propagation, with reduced higher-order mode content, improves guiding in parabolic plasma channels, enabling extended interaction lengths for laser-plasma accelerator applications.

Higher-order force moments of active particles

NASA Astrophysics Data System (ADS)

Nasouri, Babak; Elfring, Gwynn J.

2018-04-01

Active particles moving through fluids generate disturbance flows due to their activity. For simplicity, the induced flow field is often modeled by the leading terms in a far-field approximation of the Stokes equations, whose coefficients are the force, torque, and stresslet (zeroth- and first-order force moments) of the active particle. This level of approximation is quite useful, but may also fail to predict more complex behaviors that are observed experimentally. In this study, to provide a better approximation, we evaluate the contribution of the second-order force moments to the flow field and, by reciprocal theorem, present explicit formulas for the stresslet dipole, rotlet dipole, and potential dipole for an arbitrarily shaped active particle. As examples of this method, we derive modified Faxén laws for active spherical particles and resolve higher-order moments for active rod-like particles.

Possible higher order phase transition in large-N gauge theory at finite temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishimura, Hiromichi

2017-08-07

We analyze the phase structure of SU(¥) gauge theory at finite temperature using matrix models. Our basic assumption is that the effective potential is dominated by double-trace terms for the Polyakov loops. As a function of the temperature, a background field for the Polyakov loop, and a quartic coupling, it exhibits a universal structure: in the large portion of the parameter space, there is a continuous phase transition analogous to the third-order phase transition of Gross,Witten and Wadia, but the order of phase transition can be higher than third. We show that different confining potentials give rise to drastically differentmore » behavior of the eigenvalue density and the free energy. Therefore lattice simulations at large N could probe the order of phase transition and test our results. Critical« less

Unified formalism for higher order non-autonomous dynamical systems

NASA Astrophysics Data System (ADS)

Prieto-Martínez, Pedro Daniel; Román-Roy, Narciso

2012-03-01

This work is devoted to giving a geometric framework for describing higher order non-autonomous mechanical systems. The starting point is to extend the Lagrangian-Hamiltonian unified formalism of Skinner and Rusk for these kinds of systems, generalizing previous developments for higher order autonomous mechanical systems and first-order non-autonomous mechanical systems. Then, we use this unified formulation to derive the standard Lagrangian and Hamiltonian formalisms, including the Legendre-Ostrogradsky map and the Euler-Lagrange and the Hamilton equations, both for regular and singular systems. As applications of our model, two examples of regular and singular physical systems are studied.

Measurement of distributed strain and temperature based on higher order and higher mode Bragg conditions

NASA Technical Reports Server (NTRS)

Sirkis, James S. (Inventor); Sivanesan, Ponniah (Inventor); Venkat, Venki S. (Inventor)

2001-01-01

A Bragg grating sensor for measuring distributed strain and temperature at the same time comprises an optical fiber having a single mode operating wavelength region and below a cutoff wavelength of the fiber having a multimode operating wavelength region. A saturated, higher order Bragg grating having first and second order Bragg conditions is fabricated in the optical fiber. The first order of Bragg resonance wavelength of the Bragg grating is within the single mode operating wavelength region of the optical fiber and the second order of Bragg resonance wavelength is below the cutoff wavelength of the fiber within the multimode operating wavelength region. The reflectivities of the saturated Bragg grating at the first and second order Bragg conditions are less than two orders of magnitude of one another. In use, the first and second order Bragg conditions are simultaneously created in the sensor at the respective wavelengths and a signal from the sensor is demodulated with respect to each of the wavelengths corresponding to the first and second order Bragg conditions. Two Bragg conditions have different responsivities to strain and temperature, thus allowing two equations for axial strain and temperature to be found in terms of the measure shifts in the primary and second order Bragg wavelengths. This system of equations can be solved for strain and temperature.

Higher-Order Nonlinear Effects on Wave Structures in a Multispecies Plasma with Nonisothermal Electrons

NASA Astrophysics Data System (ADS)

Gill, Tarsem Singh; Bala, Parveen; Kaur, Harvinder

2010-04-01

In the present investigation, we have studied ion-acoustic solitary waves in a plasma consisting of warm positive and negative ions and nonisothermal electron distribution. We have used reductive perturbation theory (RPT) and derived a dispersion relation which supports only two ion-acoustic modes, viz. slow and fast. The expression for phase velocities of these modes is observed to be a function of parameters like nonisothermality, charge and mass ratio, and relative temperature of ions. A modified Korteweg-de Vries (KdV) equation with a (1+1/2) nonlinearity, also known as Schamel-mKdV model, is derived. RPT is further extended to include the contribution of higher-order terms. The results of numerical computation for such contributions are shown in the form of graphs in different parameter regimes for both, slow and fast ion-acoustic solitary waves having several interesting features. For the departure from the isothermally distributed electrons, a generalized KdV equation is derived and solved. It is observed that both rarefactive and compressive solitons exist for the isothermal case. However, nonisothermality supports only the compressive type of solitons in the given parameter regime.

Development of high performance particle in cell code for the exascale age

NASA Astrophysics Data System (ADS)

Lapenta, Giovanni; Amaya, Jorge; Gonzalez, Diego; Deep-Est H2020 Consortium Collaboration

2017-10-01

Magnetized plasmas are most effectively described by magneto-hydrodynamics, MHD, a fluid theory based on describing some fields defined in space: electromagnetic fields, density, velocity and temperature of the plasma. However, microphysics processes need kinetic theory, where statistical distributions of particles are governed by the Boltzmann equation. While fluid models are based on the ordinary space and time, kinetic models require a six dimensional space, called phase space, besides time. The two methods are not separated but rather interact to determine the system evolution. Arriving at a single self-consistent model is the goal of our research. We present a new approach developed with the goal of extending the reach of kinetic models to the fluid scales. Kinetic models are a higher order description and all fluid effects are included in them. However, the cost in terms of computing power is much higher and it has been so far prohibitively expensive to treat space weather events fully kinetically. We have now designed a new method capable of reducing that cost by several orders of magnitude making it possible for kinetic models to study macroscopic systems. H2020 Deep-EST consortium (European Commission).

Puzzle Pieces: Neural Structure and Function in Prader-Willi Syndrome

PubMed Central

Manning, Katherine E.; Holland, Anthony J.

2015-01-01

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder of genomic imprinting, presenting with a behavioural phenotype encompassing hyperphagia, intellectual disability, social and behavioural difficulties, and propensity to psychiatric illness. Research has tended to focus on the cognitive and behavioural investigation of these features, and, with the exception of eating behaviour, the neural physiology is currently less well understood. A systematic review was undertaken to explore findings relating to neural structure and function in PWS, using search terms designed to encompass all published articles concerning both in vivo and post-mortem studies of neural structure and function in PWS. This supported the general paucity of research in this area, with many articles reporting case studies and qualitative descriptions or focusing solely on the overeating behaviour, although a number of systematic investigations were also identified. Research to date implicates a combination of subcortical and higher order structures in PWS, including those involved in processing reward, motivation, affect and higher order cognitive functions, with both anatomical and functional investigations indicating abnormalities. It appears likely that PWS involves aberrant activity across distributed neural networks. The characterisation of neural structure and function warrants both replication and further systematic study. PMID:28943631

Puzzle Pieces: Neural Structure and Function in Prader-Willi Syndrome.

PubMed

Manning, Katherine E; Holland, Anthony J

2015-12-17

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder of genomic imprinting, presenting with a behavioural phenotype encompassing hyperphagia, intellectual disability, social and behavioural difficulties, and propensity to psychiatric illness. Research has tended to focus on the cognitive and behavioural investigation of these features, and, with the exception of eating behaviour, the neural physiology is currently less well understood. A systematic review was undertaken to explore findings relating to neural structure and function in PWS, using search terms designed to encompass all published articles concerning both in vivo and post-mortem studies of neural structure and function in PWS. This supported the general paucity of research in this area, with many articles reporting case studies and qualitative descriptions or focusing solely on the overeating behaviour, although a number of systematic investigations were also identified. Research to date implicates a combination of subcortical and higher order structures in PWS, including those involved in processing reward, motivation, affect and higher order cognitive functions, with both anatomical and functional investigations indicating abnormalities. It appears likely that PWS involves aberrant activity across distributed neural networks. The characterisation of neural structure and function warrants both replication and further systematic study.

Adaptive signal processing and higher order time- frequency analysis for acoustic and vibration signatures in condition monitoring

NASA Astrophysics Data System (ADS)

Lee, Sang-Kwon

This thesis is concerned with the development of a useful engineering technique to detect and analyse faults in rotating machinery. The methods developed are based on the advanced signal processing such as the adaptive signal processing and higher-order time frequency methods. The two-stage Adaptive Line Enhancer (ALE), using adaptive signal processing, has been developed for increasing the Signal to Noise Ratio of impulsive signals. The enhanced signal can then be analysed using time frequency methods to identify fault characteristics. However, if after pre-processing by the two stage ALE, the SNR of the signals is low, the residual noise often hinders clear identification of the fault characteristics in the time-frequency domain. In such cases, higher order time-frequency methods have been proposed and studied. As examples of rotating machinery, the internal combustion engine and an industrial gear box are considered in this thesis. The noise signal from an internal combustion engine and vibration signal measured on a gear box are studied in detail. Typically an impulsive signal manifests itself when the fault occurs in the machinery and is embedded in background noise, such as the fundamental frequency and its harmonic orders of the rotation speed and broadband noise. The two-stage ALE is developed for reducing this background noise. Conditions for the choice of adaptive filter parameters are studied and suitable adaptive algorithms given. The enhanced impulsive signal is analysed in the time- frequency domain using the Wigner higher order moment spectra (WHOMS) and the multi-time WHOMS (which is a dual form of the WHOMS). The WHOMS suffers from unwanted cross-terms, which increase dramatically as the order increases. Novel expressions for the cross-terms in WHOMS have been presented. The number of cross-terms can be reduced by taking the principal slice of the WHOMS. The residual cross-terms are smoothed by using a general class of kernel functions and the γ-method kernel function which is a novel development in this thesis. The WVD and the sliced WHOMS for synthesised signals and measured data from rotating machinery are analysed. The estimated ROC (Receive Operating Characteristic) curves for these methods are computed. These results lead to the conclusion that the detection performance when using the sliced WHOMS, for impulsive signals in embedded in broadband noise, is better than that of the Wigner-Ville distribution. Real data from a faulty car engine and faulty industrial gears are analysed. The car engine radiates an impulsive noise signal due to the loosening of a spark plug. The faulty industrial gear produces an impulsive vibration signal due to a spall on the tooth face in gear. The two- stage ALE and WHOMS are successfully applied to detection and analysis of these impulsive signals.

Convergent sum of gradient expansion of the kinetic-energy density functional up to the sixth order term using Padé approximant

NASA Astrophysics Data System (ADS)

Sergeev, A.; Alharbi, F. H.; Jovanovic, R.; Kais, S.

2016-04-01

The gradient expansion of the kinetic energy density functional, when applied to atoms or finite systems, usually grossly overestimates the energy in the fourth order and generally diverges in the sixth order. We avoid the divergence of the integral by replacing the asymptotic series including the sixth order term in the integrand by a rational function. Padé approximants show moderate improvements in accuracy in comparison with partial sums of the series. The results are discussed for atoms and Hooke’s law model for two-electron atoms.

Design and Application of Strategies/Tactics in Higher Order Logics

NASA Technical Reports Server (NTRS)

Archer, Myla (Editor); diVito, Ben (Editor); Munoz, Cesar (Editor)

2003-01-01

This Proceedings includes both a paper from the implementors of PVS providing guidance for PVS strategy writers and a tutorial on PVS strategy writing distilled from the experience of three PVS users who have written extensive sets of PVS user strategies. Following these are three full papers from the higher-order logic theorem proving community that discuss PVS strategies to enhance arithmetic and other interactive reasoning in PVS; implementing first-order tactics in higher-order provers; and a proposed technique for specifying small step semantics that can be used in multiple higher order logic theorem provers, with illustrations from both Coq and PVS. The Proceedings concludes with three position papers for a panel session that discuss three settings in which development of PVS strategies is worth while.

Vector spherical quasi-Gaussian vortex beams

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2014-02-01

Model equations for describing and efficiently computing the radiation profiles of tightly spherically focused higher-order electromagnetic beams of vortex nature are derived stemming from a vectorial analysis with the complex-source-point method. This solution, termed as a high-order quasi-Gaussian (qG) vortex beam, exactly satisfies the vector Helmholtz and Maxwell's equations. It is characterized by a nonzero integer degree and order (n,m), respectively, an arbitrary waist w0, a diffraction convergence length known as the Rayleigh range zR, and an azimuthal phase dependency in the form of a complex exponential corresponding to a vortex beam. An attractive feature of the high-order solution is the rigorous description of strongly focused (or strongly divergent) vortex wave fields without the need of either the higher-order corrections or the numerically intensive methods. Closed-form expressions and computational results illustrate the analysis and some properties of the high-order qG vortex beams based on the axial and transverse polarization schemes of the vector potentials with emphasis on the beam waist.

Election-Year Bonus: Glossary of Congressional Terms

ERIC Educational Resources Information Center

Social Education, 1978

1978-01-01

The glossary present definitions of over 120 political terms, including appropriation bill, budget, contract authorizations, congressional record, minority leader, override a veto, readings of bills, point of order, and adjournment sine die. (DB)

Symmetry operators of Killing spinors and superalgebras in AdS5

NASA Astrophysics Data System (ADS)

Ertem, Ümit

2016-04-01

We construct the first-order symmetry operators of Killing spinor equation in terms of odd Killing-Yano forms. By modifying the Schouten-Nijenhuis bracket of Killing-Yano forms, we show that the symmetry operators of Killing spinors close into an algebra in AdS5 spacetime. Since the symmetry operator algebra of Killing spinors corresponds to a Jacobi identity in extended Killing superalgebras, we investigate the possible extensions of Killing superalgebras to include higher-degree Killing-Yano forms. We found that there is a superalgebra extension but no Lie superalgebra extension of the Killing superalgebra constructed out of Killing spinors and odd Killing-Yano forms in AdS5 background.

mTOR signaling: at the crossroads of plasticity, memory and disease.

PubMed

Hoeffer, Charles A; Klann, Eric

2010-02-01

Mammalian target of rapamycin (mTOR) is a protein kinase involved in translation control and long-lasting synaptic plasticity. mTOR functions as the central component of two multi-protein signaling complexes, mTORC1 and mTORC2, which can be distinguished from each other based on their unique compositions and substrates. Although the majority of evidence linking mTOR function to synaptic plasticity comes from studies utilizing rapamycin, studies in genetically modified mice also suggest that mTOR couples receptors to the translation machinery for establishing long-lasting synaptic changes that are the basis for higher order brain function, including long-term memory. Finally, perturbation of the mTOR signaling cascade appears to be a common pathophysiological feature of human neurological disorders, including mental retardation syndromes and autism spectrum disorders. (c) 2009 Elsevier Ltd. All rights reserved.

The cause of outliers in electromagnetic pulse (EMP) locations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fenimore, Edward E.

2014-10-02

We present methods to calculate the location of EMP pulses when observed by 5 or more satellites. Simulations show that, even with a good initial guess and fitting a location to all of the data, there are sometime outlier results whose locations are much worse than most cases. By comparing simulations using different ionospheric transfer functions (ITFs), it appears that the outliers are caused by not including the additional path length due to refraction rather than being caused by not including higher order terms in the Appleton-Hartree equation. We suggest ways that the outliers can be corrected. These correction methodsmore » require one to use an electron density profile along the line of sight from the event to the satellite rather than using the total electron content (TEC) to characterize the ionosphere.« less

mTOR Signaling: At the Crossroads of Plasticity, Memory, and Disease

PubMed Central

Hoeffer, Charles A.; Klann, Eric

2009-01-01

Mammalian target of rapamycin (mTOR) is a protein kinase involved in translation control and long-lasting synaptic plasticity. mTOR functions as the central component of two multi-protein signaling complexes, mTORC1 and mTORC2, which can be distinguished from each other based on their unique compositions and substrates. Although majority of evidence linking mTOR function to synaptic plasticity comes from studies utilizing rapamycin, studies in genetically-modified mice also suggest that mTOR couples receptors to the translation machinery for establishing long-lasting synaptic changes that are the basis for higher order brain function, including long-term memory. Finally, perturbation of the mTOR signaling cascade appears to be a common pathophysiological feature of human neurological disorders, including mental retardation syndromes and autism spectrum disorders. PMID:19963289

Development of Self-Belief for Employability in Higher Education: Ability, Efficacy and Control in Context

ERIC Educational Resources Information Center

Turner, Nancy K.

2014-01-01

Self-belief is argued here to be a key aspect of employability development that has been largely under conceptualisation in terms of what the construct may mean and how it may be developed through higher education (HE) study. This paper proposes three fundamental beliefs that need to be fostered in order to develop student self-belief: (1) that…

Investigating Stratification within Higher Education through Examining the Status of Students in Different Academic Majors in Terms of Cultural, Social and Economic Capital

ERIC Educational Resources Information Center

Hassani, Mohammad; Ghasemi, Seyyed Jamal Mir

2016-01-01

This study was carried out in order to explore the status of stratification within higher education through measuring cultural, economic and social capital of students in major academic disciplines across universities in Urmia, Northwestern Iran. The findings indicate that there are stratification structures in the presence of students in…

An Evaluation of Student Outcomes by Course Duration in Online Higher Education

ERIC Educational Resources Information Center

Shaw, Melanie; Chametzky, Barry; Burrus, Scott W.; Walters, Kelley J.

2013-01-01

To facilitate student learning and ensure financial stability, leaders in higher education institutions offering online degrees and programs are adopting flexible course schedules with shorter terms. The literature does not include many evaluations demonstrating how shorter duration terms and courses might affect student achievement. In this…

Issues and Methods Concerning the Evaluation of Hypersingular and Near-Hypersingular Integrals in BEM Formulations

NASA Technical Reports Server (NTRS)

Fink, P. W.; Khayat, M. A.; Wilton, D. R.

2005-01-01

It is known that higher order modeling of the sources and the geometry in Boundary Element Modeling (BEM) formulations is essential to highly efficient computational electromagnetics. However, in order to achieve the benefits of hIgher order basis and geometry modeling, the singular and near-singular terms arising in BEM formulations must be integrated accurately. In particular, the accurate integration of near-singular terms, which occur when observation points are near but not on source regions of the scattering object, has been considered one of the remaining limitations on the computational efficiency of integral equation methods. The method of singularity subtraction has been used extensively for the evaluation of singular and near-singular terms. Piecewise integration of the source terms in this manner, while manageable for bases of constant and linear orders, becomes unwieldy and prone to error for bases of higher order. Furthermore, we find that the singularity subtraction method is not conducive to object-oriented programming practices, particularly in the context of multiple operators. To extend the capabilities, accuracy, and maintainability of general-purpose codes, the subtraction method is being replaced in favor of the purely numerical quadrature schemes. These schemes employ singularity cancellation methods in which a change of variables is chosen such that the Jacobian of the transformation cancels the singularity. An example of the sin,oularity cancellation approach is the Duffy method, which has two major drawbacks: 1) In the resulting integrand, it produces an angular variation about the singular point that becomes nearly-singular for observation points close to an edge of the parent element, and 2) it appears not to work well when applied to nearly-singular integrals. Recently, the authors have introduced the transformation u(x(prime))= sinh (exp -1) x(prime)/Square root of ((y prime (exp 2))+ z(exp 2) for integrating functions of the form I = Integral of (lambda(r(prime))((e(exp -jkR))/(4 pi R) d D where A (r (prime)) is a vector or scalar basis function and R = Square root of( (x(prime)(exp2) + (y(prime)(exp2) + z(exp 2)) is the distance between source and observation points. This scheme has all of the advantages of the Duffy method while avoiding the disadvantages listed above. In this presentation we will survey similar approaches for handling singular and near-singular terms for kernels with 1/R(exp 2) type behavior, addressing potential pitfalls and offering techniques to efficiently handle special cases.

Fast higher-order MR image reconstruction using singular-vector separation.

PubMed

Wilm, Bertram J; Barmet, Christoph; Pruessmann, Klaas P

2012-07-01

Medical resonance imaging (MRI) conventionally relies on spatially linear gradient fields for image encoding. However, in practice various sources of nonlinear fields can perturb the encoding process and give rise to artifacts unless they are suitably addressed at the reconstruction level. Accounting for field perturbations that are neither linear in space nor constant over time, i.e., dynamic higher-order fields, is particularly challenging. It was previously shown to be feasible with conjugate-gradient iteration. However, so far this approach has been relatively slow due to the need to carry out explicit matrix-vector multiplications in each cycle. In this work, it is proposed to accelerate higher-order reconstruction by expanding the encoding matrix such that fast Fourier transform can be employed for more efficient matrix-vector computation. The underlying principle is to represent the perturbing terms as sums of separable functions of space and time. Compact representations with this property are found by singular-vector analysis of the perturbing matrix. Guidelines for balancing the accuracy and speed of the resulting algorithm are derived by error propagation analysis. The proposed technique is demonstrated for the case of higher-order field perturbations due to eddy currents caused by diffusion weighting. In this example, image reconstruction was accelerated by two orders of magnitude.

Higher Serum Uric Acid on Admission Is Associated with Higher Short-term Mortality and Poorer Long-term Survival After Myocardial Infarction: Retrospective Prognostic Study

PubMed Central

Car, Siniša; Trkulja, Vladimir

2009-01-01

Aim To assess serum uric acid (SUA) levels determined on admission as a potential predictor of short-term mortality and long-term survival in acute myocardial infarction (AMI) patients. Method Data for this retrospective prognostic study were drawn from the patient database of the Varaždin County General Hospital in Varaždin, Croatia. We included consecutive patients with verified AMI admitted within 48 hours since the symptom onset during the period between January 1, 1996 and December 31, 2001. Long-term survival/mortality data were collected through direct contacts with patients and search of the community death registries. Relative risks (RR) and hazard ratios (HR) by 10 µmol/L increase in SUA were determined using modified Poisson regression with robust error variance and proportional hazard regression, respectively. Results A total of 621 patients (age 27-90 years, 64.7% men, 77.5% AMI with ST elevation, SUA 63-993 µmol/L) were included. Higher SUA on admission was independently associated with higher in-hospital mortality (RR, 1.016; 95% confidence interval [CI], 1.001-1.031, P = 0.043) and higher thirty-day mortality (RR, 1.016; 95% CI, 1.003-1.029, P = 0.018). Considered covariates were demographics, pre-index event cardiovascular morbidity and treatment, on-admission serum creatinine, total cholesterol and triglycerides, AMI characteristics, and peak creatine phosphokinase. Higher SUA on admission was also independently associated with poorer long-term survival (ie, higher all-cause mortality) (HR, 1.105; 95% CI, 1.020-1.195, P = 0.010). Considered covariates were demographics, laboratory variables on admission, AMI characteristics, peak creatine phosphokinase, acute complications, and treatment at discharge. Conclusion Higher serum uric acid determined on admission is associated with higher in-hospital mortality and thirty-day mortality and poorer long-term survival after AMI. PMID:20017224

Adverse pregnancy outcomes following syphilis treatment in pregnancy in the UK.

PubMed

Wallace, Harriet E; Isitt, Catherine E; Broomhall, Harriet M; Perry, Alison E; Wilson, Janet D

2016-10-01

Syphilis infection in pregnancy is known to cause a number of severe adverse pregnancy outcomes, including second-trimester miscarriage, stillbirth, very pre-term delivery and neonatal death, in addition to congenital syphilis. A retrospective review of women with positive syphilis serology and a pregnancy outcome between 2005 and 2012 in Leeds, UK, was performed. In all, 57 cases of positive syphilis serology in pregnancy were identified: 24 with untreated syphilis treated in the current pregnancy (Group 1); seven with reported but unconfirmed prior treatment who were retreated (Group 2); and 26 adequately treated prior to pregnancy (Group 3). The rate of severe adverse pregnancy outcomes in Group 1 at 21% was significantly higher than the 0% outcome of Group 3 (p = 0.02). The severe adverse pregnancy outcomes were two second-trimester miscarriages, two pre-term births at 25 and 28 weeks and one stillbirth at 32 weeks. There were no cases of term congenital syphilis or term neonatal death, but we observed high rates of other adverse pregnancy outcomes despite treatment during pregnancy. Rapid referral for treatment is needed before 18 weeks in order to minimise adverse pregnancy outcomes. © The Author(s) 2016.

A shock capturing technique for hypersonic, chemically relaxing flows

NASA Technical Reports Server (NTRS)

Eberhardt, S.; Brown, K.

1986-01-01

A fully coupled, shock capturing technique is presented for chemically reacting flows at high Mach numbers. The technique makes use of a total variation diminishing (TVD) dissipation operator which results in sharp, crisp shocks. The eigenvalues and eigenvectors of the fully coupled system, which includes species conversion equations in addition to the gas dynamics equations, are analytically derived for a general reacting gas. Species production terms for a model dissociating gas are introduced and are included in the algorithm. The convective terms are solved using a first-order TVD scheme while the source terms are solved using a fourth-order Runge-Kutta scheme to enhance stability. Results from one-dimensional numerical experiments are shown for a two species and a three species gas.

Higher-order formulas of amplitude-dependent tune shift caused by a sextupole magnetic field distribution

NASA Astrophysics Data System (ADS)

Soutome, Kouichi; Tanaka, Hitoshi

2017-06-01

Nowadays, designs for ring-based light sources use multibend lattices for achieving a very small emittance of around 100 pmrad. In this type of storage ring, the chromaticity correcting sextupoles generally have greater strengths than those used in typical third-generation light sources. Therefore, controlling lattice nonlinearity such as amplitude-dependent tune shift (ADTS) is important for enabling stable operations and smooth beam commissioning. As the strength of the sextupoles increases, their higher-order terms contribute significantly to ADTS, rendering well-known lowest-order formulas inadequate for describing tune variations at large horizontal amplitudes. In response, we have derived explicit expressions of ADTS up to the fourth order in sextupole strength based on the canonical perturbation theory, assuming that the amplitude of a vertical betatron oscillation is smaller compared with the horizontal one. The new formulas express the horizontal and vertical betatron tune variations as functions of the action variables: Jx and Jy up to O (Jx2) and O (Jy) . The derived formulas were applied to a five-bend achromat lattice designed for the SPring-8 upgrade. By comparing the calculated results with the tracking simulations, we found that (1) the formulas accurately express ADTS around a horizontal amplitude of ˜10 mm and (2) the nonlinear terms of the fourth order in sextupole strength govern the behaviors of circulating electrons at large horizontal amplitudes. In this paper, we present explicit expressions of fourth-order formulas of ADTS and provide some examples to illustrate their effectiveness.

Navigation System Design and State Estimation for a Small Rigid Hull Inflatable Boat (RHIB)

DTIC Science & Technology

2014-09-01

addition of the Coriolis term as previously defined has no effect on pitch, only one measurement is compared against Condor’s true pitch angle values...33  B.  REFERENCE FRAME DEFINITIONS ......................................................33  1.  Earth Centered Inertial...the effect of higher order terms. Lastly, the zeroth weight of the scaled weight set can be modified to incorporate prior knowledge of the

Improved Knowledge Retention Among Clinical Pharmacy Students Using an Anthropology Classroom Assessment Technique

PubMed Central

Parton, Jason M.

2014-01-01

Objective. To adapt a classroom assessment technique (CAT) from an anthropology course to a diabetes module in a clinical pharmacy skills laboratory and to determine student knowledge retention from baseline. Design. Diabetes item stems, focused on module objectives, replaced anthropology terms. Answer choices, coded to Bloom’s Taxonomy, were expanded to include higher-order thinking. Students completed the online 5-item probe 4 times: prelaboratory lecture, postlaboratory, and at 6 months and 12 months after laboratory. Statistical analyses utilized a single factor, repeated measures design using rank transformations of means with a Mann-Whitney-Wilcoxon test. Assessment. The CAT revealed a significant increase in knowledge from prelaboratory compared to all postlaboratory measurements (p<0.0001). Significant knowledge retention was maintained with basic terms, but declined with complex terms between 6 and 12 months. Conclusion. The anthropology assessment tool was effectively adapted using Bloom’s Taxonomy as a guide and, when used repeatedly, demonstrated knowledge retention. Minimal time was devoted to application of the probe making it an easily adaptable CAT. PMID:25258445

Development of a second order closure model for computation of turbulent diffusion flames

NASA Technical Reports Server (NTRS)

Varma, A. K.; Donaldson, C. D.

1974-01-01

A typical eddy box model for the second-order closure of turbulent, multispecies, reacting flows developed. The model structure was quite general and was valid for an arbitrary number of species. For the case of a reaction involving three species, the nine model parameters were determined from equations for nine independent first- and second-order correlations. The model enabled calculation of any higher-order correlation involving mass fractions, temperatures, and reaction rates in terms of first- and second-order correlations. Model predictions for the reaction rate were in very good agreement with exact solutions of the reaction rate equations for a number of assumed flow distributions.

The fifth-order partial differential equation for the description of the α + β Fermi-Pasta-Ulam model

NASA Astrophysics Data System (ADS)

Kudryashov, Nikolay A.; Volkov, Alexandr K.

2017-01-01

We study a new nonlinear partial differential equation of the fifth order for the description of perturbations in the Fermi-Pasta-Ulam mass chain. This fifth-order equation is an expansion of the Gardner equation for the description of the Fermi-Pasta-Ulam model. We use the potential of interaction between neighbouring masses with both quadratic and cubic terms. The equation is derived using the continuous limit. Unlike the previous works, we take into account higher order terms in the Taylor series expansions. We investigate the equation using the Painlevé approach. We show that the equation does not pass the Painlevé test and can not be integrated by the inverse scattering transform. We use the logistic function method and the Laurent expansion method to find travelling wave solutions of the fifth-order equation. We use the pseudospectral method for the numerical simulation of wave processes, described by the equation.

Nuclear recoil effect on the binding energies in highly charged He-like ions

NASA Astrophysics Data System (ADS)

Malyshev, A. V.; Popov, R. V.; Shabaev, V. M.; Zubova, N. A.

2018-04-01

The most precise to-date evaluation of the nuclear recoil effect on the n = 1 and n = 2 energy levels of He-like ions is presented in the range Z = 12–100. The one-electron recoil contribution is calculated within the framework of the rigorous quantum electrodynamics approach to first order in the electron-to-nucleus mass ratio m/M and to all orders in the parameter αZ. The two-electron m/M recoil term is calculated employing the 1/Z perturbation theory. The recoil contribution of the zeroth order in 1/Z is evaluated to all orders in αZ, while the 1/Z term is calculated using the Breit approximation. The recoil corrections of the second and higher orders in 1/Z are taken into account within the nonrelativistic approach. The obtained results are compared with the previous evaluation of this effect (Artemyev et al 2005 Phys. Rev. A 71 062104).

Progress in the Development of a Class of Efficient Low Dissipative High Order Shock-capturing Methods

NASA Technical Reports Server (NTRS)

Yee, H. C.; Sjogreen, B.; Sandham, N. D.; Hadjadj, A.; Kwak, Dochan (Technical Monitor)

2000-01-01

In a series of papers, Olsson (1994, 1995), Olsson & Oliger (1994), Strand (1994), Gerritsen Olsson (1996), Yee et al. (1999a,b, 2000) and Sandham & Yee (2000), the issue of nonlinear stability of the compressible Euler and Navier-Stokes Equations, including physical boundaries, and the corresponding development of the discrete analogue of nonlinear stable high order schemes, including boundary schemes, were developed, extended and evaluated for various fluid flows. High order here refers to spatial schemes that are essentially fourth-order or higher away from shock and shear regions. The objective of this paper is to give an overview of the progress of the low dissipative high order shock-capturing schemes proposed by Yee et al. (1999a,b, 2000). This class of schemes consists of simple non-dissipative high order compact or non-compact central spatial differencings and adaptive nonlinear numerical dissipation operators to minimize the use of numerical dissipation. The amount of numerical dissipation is further minimized by applying the scheme to the entropy splitting form of the inviscid flux derivatives, and by rewriting the viscous terms to minimize odd-even decoupling before the application of the central scheme (Sandham & Yee). The efficiency and accuracy of these scheme are compared with spectral, TVD and fifth- order WENO schemes. A new approach of Sjogreen & Yee (2000) utilizing non-orthogonal multi-resolution wavelet basis functions as sensors to dynamically determine the appropriate amount of numerical dissipation to be added to the non-dissipative high order spatial scheme at each grid point will be discussed. Numerical experiments of long time integration of smooth flows, shock-turbulence interactions, direct numerical simulations of a 3-D compressible turbulent plane channel flow, and various mixing layer problems indicate that these schemes are especially suitable for practical complex problems in nonlinear aeroacoustics, rotorcraft dynamics, direct numerical simulation or large eddy simulation of compressible turbulent flows at various speeds including high-speed shock-turbulence interactions, and general long time wave propagation problems. These schemes, including entropy splitting, have also been extended to freestream preserving schemes on curvilinear moving grids for a thermally perfect gas (Vinokur & Yee 2000).

R4 terms in supergravities via T -duality constraint

NASA Astrophysics Data System (ADS)

Razaghian, Hamid; Garousi, Mohammad R.

2018-05-01

It has been speculated in the literature that the effective actions of string theories at any order of α' should be invariant under the Buscher rules plus their higher covariant-derivative corrections. This may be used as a constraint to find effective actions at any order of α', in particular, the metric, the B -field, and the dilaton couplings in supergravities at order α'3 up to an overall factor. For the simple case of zero B -field and diagonal metric in which we have done the calculations explicitly, we have found that the constraint fixes almost all of the seven independent Riemann curvature couplings. There is only one term which is not fixed, because when metric is diagonal, the reduction of two R4 terms becomes identical. The Riemann curvature couplings that the T -duality constraint produces for both type II and heterotic theories are fully consistent with the existing couplings in the literature which have been found by the S-matrix and by the sigma-model approaches.

Higher-order modulation instability in nonlinear fiber optics.

PubMed

Erkintalo, Miro; Hammani, Kamal; Kibler, Bertrand; Finot, Christophe; Akhmediev, Nail; Dudley, John M; Genty, Goëry

2011-12-16

We report theoretical, numerical, and experimental studies of higher-order modulation instability in the focusing nonlinear Schrödinger equation. This higher-order instability arises from the nonlinear superposition of elementary instabilities, associated with initial single breather evolution followed by a regime of complex, yet deterministic, pulse splitting. We analytically describe the process using the Darboux transformation and compare with experiments in optical fiber. We show how a suitably low frequency modulation on a continuous wave field induces higher-order modulation instability splitting with the pulse characteristics at different phases of evolution related by a simple scaling relationship. We anticipate that similar processes are likely to be observed in many other systems including plasmas, Bose-Einstein condensates, and deep water waves. © 2011 American Physical Society

Dark solitons in the presence of higher-order effects.

PubMed

Horikis, Theodoros P; Frantzeskakis, Dimitrios J

2013-12-01

Dark soliton propagation is studied in the presence of higher-order effects, including third-order dispersion, self-steepening, linear/nonlinear gain/loss, and Raman scattering. It is found that for certain values of the parameters a stable evolution can exist for both the soliton and the relative continuous-wave background. Using a newly developed perturbation theory we show that the perturbing effects give rise to a shelf that accompanies the soliton in its propagation. Although, the stable solitons are not affected by the shelf it remains an integral part of the dynamics otherwise not considered so far in studies of higher-order nonlinear Schrödinger models.

Next-to-next-to-leading order gravitational spin-orbit coupling via the effective field theory for spinning objects in the post-Newtonian scheme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levi, Michele; Steinhoff, Jan, E-mail: michele.levi@upmc.fr, E-mail: jan.steinhoff@aei.mpg.de

2016-01-01

We implement the effective field theory for gravitating spinning objects in the post-Newtonian scheme at the next-to-next-to-leading order level to derive the gravitational spin-orbit interaction potential at the third and a half post-Newtonian order for rapidly rotating compact objects. From the next-to-next-to-leading order interaction potential, which we obtain here in a Lagrangian form for the first time, we derive straightforwardly the corresponding Hamiltonian. The spin-orbit sector constitutes the most elaborate spin dependent sector at each order, and accordingly we encounter a proliferation of the relevant Feynman diagrams, and a significant increase of the computational complexity. We present in detail themore » evaluation of the interaction potential, going over all contributing Feynman diagrams. The computation is carried out in terms of the ''nonrelativistic gravitational'' fields, which are advantageous also in spin dependent sectors, together with the various gauge choices included in the effective field theory for gravitating spinning objects, which also optimize the calculation. In addition, we automatize the effective field theory computations, and carry out the automated computations in parallel. Such automated effective field theory computations would be most useful to obtain higher order post-Newtonian corrections. We compare our Hamiltonian to the ADM Hamiltonian, and arrive at a complete agreement between the ADM and effective field theory results. Finally, we provide Hamiltonians in the center of mass frame, and complete gauge invariant relations among the binding energy, angular momentum, and orbital frequency of an inspiralling binary with generic compact spinning components to third and a half post-Newtonian order. The derivation presented here is essential to obtain further higher order post-Newtonian corrections, and to reach the accuracy level required for the successful detection of gravitational radiation.« less

Deviation pattern approach for optimizing perturbative terms of QCD renormalization group invariant observables

NASA Astrophysics Data System (ADS)

Khellat, M. R.; Mirjalili, A.

2017-03-01

We first consider the idea of renormalization group-induced estimates, in the context of optimization procedures, for the Brodsky-Lepage-Mackenzie approach to generate higher-order contributions to QCD perturbative series. Secondly, we develop the deviation pattern approach (DPA) in which through a series of comparisons between lowerorder RG-induced estimates and the corresponding analytical calculations, one could modify higher-order RG-induced estimates. Finally, using the normal estimation procedure and DPA, we get estimates of αs4 corrections for the Bjorken sum rule of polarized deep-inelastic scattering and for the non-singlet contribution to the Adler function.

Effects of static equilibrium and higher-order nonlinearities on rotor blade stability in hover

NASA Technical Reports Server (NTRS)

Crespodasilva, Marcelo R. M.; Hodges, Dewey H.

1988-01-01

The equilibrium and stability of the coupled elastic lead/lag, flap, and torsion motion of a cantilever rotor blade in hover are addressed, and the influence of several higher-order terms in the equations of motion of the blade is determined for a range of values of collective pitch. The blade is assumed to be untwisted and to have uniform properties along its span. In addition, chordwise offsets between its elastic, tension, mass, and aerodynamic centers are assumed to be negligible for simplicity. The aerodynamic forces acting on the blade are modeled using a quasi-steady, strip-theory approximation.

Dipolar ordering and glassy freezing in methanol-{beta}-hydroquinone-clathrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woll, H.; Rheinstadter, M. C.; Kruchten, F.

2001-06-01

The dielectric, structural, and thermodynamic properties of single crystals of methanol-{beta}-hydroquinone-clathrates have been studied as function of temperature and of the concentration x of the polar guest molecules. At higher temperatures the dielectric response along the threefold crystal axis is of the quasi-one-dimensional Ising type. At lower temperatures the higher concentrated samples order antiferroelectrically whereas the lower concentrated ones freeze into dipole glasses. The behavior is interpreted in terms of the methanol dipole moments coupled by the electric dipole-dipole interaction which is highly frustrated because of the rhombohedral symmetry of the lattice. The dielectric relaxations have been analyzed.

34 CFR 686.25 - Correspondence study.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF EDUCATION (CONTINUED) TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH... without terms, but not including any residential component, by— (1) Using the half-time annual award; and... correspondence courses using terms but not including any residential component— (1) The institution must prepare...

34 CFR 686.25 - Correspondence study.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF EDUCATION (CONTINUED) TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH... without terms, but not including any residential component, by— (1) Using the half-time annual award; and... correspondence courses using terms but not including any residential component— (1) The institution must prepare...

34 CFR 686.25 - Correspondence study.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF EDUCATION (CONTINUED) TEACHER EDUCATION ASSISTANCE FOR COLLEGE AND HIGHER EDUCATION (TEACH... without terms, but not including any residential component, by— (1) Using the half-time annual award; and... correspondence courses using terms but not including any residential component— (1) The institution must prepare...

Superconducting order from disorder in 2H-TaSe2-xSx

NASA Astrophysics Data System (ADS)

Li, Lijun; Deng, Xiaoyu; Wang, Zhen; Liu, Yu; Abeykoon, Milinda; Dooryhee, Eric; Tomic, Aleksandra; Huang, Yanan; Warren, John B.; Bozin, Emil S.; Billinge, Simon J. L.; Sun, Yuping; Zhu, Yimei; Kotliar, Gabriel; Petrovic, Cedomir

2017-12-01

We report on the emergence of robust superconducting order in single crystal alloys of TaSe2-xSx (0 ≤ × ≤ 2). The critical temperature of the alloy is surprisingly higher than that of the two end compounds TaSe2 and TaS2. The evolution of superconducting critical temperature Tc(x) correlates with the full width at half maximum of the Bragg peaks and with the linear term of the high-temperature resistivity. The conductivity of the crystals near the middle of the alloy series is higher or similar than that of either one of the end members 2H-TaSe2 and/or 2H-TaS2. It is known that in these materials superconductivity is in close competition with charge density wave order. We interpret our experimental findings in a picture where disorder tilts this balance in favor of superconductivity by destroying the charge density wave order.

Tolerance analysis of optical telescopes using coherent addition of wavefront errors

NASA Technical Reports Server (NTRS)

Davenport, J. W.

1982-01-01

A near diffraction-limited telescope requires that tolerance analysis be done on the basis of system wavefront error. One method of analyzing the wavefront error is to represent the wavefront error function in terms of its Zernike polynomial expansion. A Ramsey-Korsch ray trace package, a computer program that simulates the tracing of rays through an optical telescope system, was expanded to include the Zernike polynomial expansion up through the fifth-order spherical term. An option to determine a 3 dimensional plot of the wavefront error function was also included in the Ramsey-Korsch package. Several assimulation runs were analyzed to determine the particular set of coefficients in the Zernike expansion that are effected by various errors such as tilt, decenter and despace. A 3 dimensional plot of each error up through the fifth-order spherical term was also included in the study. Tolerance analysis data are presented.

Open-Source Assisted Laboratory Automation through Graphical User Interfaces and 3D Printers: Application to Equipment Hyphenation for Higher-Order Data Generation.

PubMed

Siano, Gabriel G; Montemurro, Milagros; Alcaráz, Mirta R; Goicoechea, Héctor C

2017-10-17

Higher-order data generation implies some automation challenges, which are mainly related to the hidden programming languages and electronic details of the equipment. When techniques and/or equipment hyphenation are the key to obtaining higher-order data, the required simultaneous control of them demands funds for new hardware, software, and licenses, in addition to very skilled operators. In this work, we present Design of Inputs-Outputs with Sikuli (DIOS), a free and open-source code program that provides a general framework for the design of automated experimental procedures without prior knowledge of programming or electronics. Basically, instruments and devices are considered as nodes in a network, and every node is associated both with physical and virtual inputs and outputs. Virtual components, such as graphical user interfaces (GUIs) of equipment, are handled by means of image recognition tools provided by Sikuli scripting language, while handling of their physical counterparts is achieved using an adapted open-source three-dimensional (3D) printer. Two previously reported experiments of our research group, related to fluorescence matrices derived from kinetics and high-performance liquid chromatography, were adapted to be carried out in a more automated fashion. Satisfactory results, in terms of analytical performance, were obtained. Similarly, advantages derived from open-source tools assistance could be appreciated, mainly in terms of lesser intervention of operators and cost savings.

29 CFR 570.58 - Occupations involved in the operation of power-driven hoisting apparatus (Order 7).

Code of Federal Regulations, 2012 CFR

2012-07-01

... equipped with a car or platform which moves in guides in a substantially vertical direction. The term shall... force that does not include a car or platform running in guides. The term shall include all types of hoists, such as base mounted electric, clevis suspension, hook suspension, monorail, overhead electric...

29 CFR 570.58 - Occupations involved in the operation of power-driven hoisting apparatus (Order 7).

Code of Federal Regulations, 2013 CFR

2013-07-01

... equipped with a car or platform which moves in guides in a substantially vertical direction. The term shall... force that does not include a car or platform running in guides. The term shall include all types of hoists, such as base mounted electric, clevis suspension, hook suspension, monorail, overhead electric...

29 CFR 570.58 - Occupations involved in the operation of power-driven hoisting apparatus (Order 7).

Code of Federal Regulations, 2014 CFR

2014-07-01

... equipped with a car or platform which moves in guides in a substantially vertical direction. The term shall... force that does not include a car or platform running in guides. The term shall include all types of hoists, such as base mounted electric, clevis suspension, hook suspension, monorail, overhead electric...

The New Reverse Transfer: A National Landscape

ERIC Educational Resources Information Center

Friedel, Janice Nahra; Wilson, Sarah L.

2015-01-01

For decades, higher education professionals and researchers have used the term reverse transfer to describe a specific group of students. A current review of community college literature and higher education policy reflects a contextual change of the term, and today reverse transfer has grown to include students who transfer from a two-year…

Higher-order gravity in higher dimensions: geometrical origins of four-dimensional cosmology?

NASA Astrophysics Data System (ADS)

Troisi, Antonio

2017-03-01

Determining the cosmological field equations is still very much debated and led to a wide discussion around different theoretical proposals. A suitable conceptual scheme could be represented by gravity models that naturally generalize Einstein theory like higher-order gravity theories and higher-dimensional ones. Both of these two different approaches allow one to define, at the effective level, Einstein field equations equipped with source-like energy-momentum tensors of geometrical origin. In this paper, the possibility is discussed to develop a five-dimensional fourth-order gravity model whose lower-dimensional reduction could provide an interpretation of cosmological four-dimensional matter-energy components. We describe the basic concepts of the model, the complete field equations formalism and the 5-D to 4-D reduction procedure. Five-dimensional f( R) field equations turn out to be equivalent, on the four-dimensional hypersurfaces orthogonal to the extra coordinate, to an Einstein-like cosmological model with three matter-energy tensors related with higher derivative and higher-dimensional counter-terms. By considering the gravity model with f(R)=f_0R^n the possibility is investigated to obtain five-dimensional power law solutions. The effective four-dimensional picture and the behaviour of the geometrically induced sources are finally outlined in correspondence to simple cases of such higher-dimensional solutions.

Metabolic Profiling as Well as Stable Isotope Assisted Metabolic and Proteomic Analysis of RAW 264.7 Macrophages Exposed to Ship Engine Aerosol Emissions: Different Effects of Heavy Fuel Oil and Refined Diesel Fuel

PubMed Central

Sapcariu, Sean C.; Kanashova, Tamara; Dilger, Marco; Diabaté, Silvia; Oeder, Sebastian; Passig, Johannes; Radischat, Christian; Buters, Jeroen; Sippula, Olli; Streibel, Thorsten; Paur, Hanns-Rudolf; Schlager, Christoph; Mülhopt, Sonja; Stengel, Benjamin; Rabe, Rom; Harndorf, Horst; Krebs, Tobias; Karg, Erwin; Gröger, Thomas; Weiss, Carsten; Dittmar, Gunnar; Hiller, Karsten; Zimmermann, Ralf

2016-01-01

Exposure to air pollution resulting from fossil fuel combustion has been linked to multiple short-term and long term health effects. In a previous study, exposure of lung epithelial cells to engine exhaust from heavy fuel oil (HFO) and diesel fuel (DF), two of the main fuels used in marine engines, led to an increased regulation of several pathways associated with adverse cellular effects, including pro-inflammatory pathways. In addition, DF exhaust exposure was shown to have a wider response on multiple cellular regulatory levels compared to HFO emissions, suggesting a potentially higher toxicity of DF emissions over HFO. In order to further understand these effects, as well as to validate these findings in another cell line, we investigated macrophages under the same conditions as a more inflammation-relevant model. An air-liquid interface aerosol exposure system was used to provide a more biologically relevant exposure system compared to submerged experiments, with cells exposed to either the complete aerosol (particle and gas phase), or the gas phase only (with particles filtered out). Data from cytotoxicity assays were integrated with metabolomics and proteomics analyses, including stable isotope-assisted metabolomics, in order to uncover pathways affected by combustion aerosol exposure in macrophages. Through this approach, we determined differing phenotypic effects associated with the different components of aerosol. The particle phase of diluted combustion aerosols was found to induce increased cell death in macrophages, while the gas phase was found more to affect the metabolic profile. In particular, a higher cytotoxicity of DF aerosol emission was observed in relation to the HFO aerosol. Furthermore, macrophage exposure to the gas phase of HFO leads to an induction of a pro-inflammatory metabolic and proteomic phenotype. These results validate the effects found in lung epithelial cells, confirming the role of inflammation and cellular stress in the response to combustion aerosols. PMID:27348622

Problem-Based Learning and Use of Higher-Order Thinking by Emergency Medical Technicians

ERIC Educational Resources Information Center

Rosenberger, Paul

2013-01-01

Emergency Medical Technicians (EMTs) often handle chaotic life-and-death situations that require higher-order thinking skills. Improving the pass rate of EMT students depends on many factors, including the use of proven and effective teaching methods. Results from recent research about effective teaching have suggested that the instructional…

Is general intelligence little more than the speed of higher-order processing?

PubMed

Schubert, Anna-Lena; Hagemann, Dirk; Frischkorn, Gidon T

2017-10-01

Individual differences in the speed of information processing have been hypothesized to give rise to individual differences in general intelligence. Consistent with this hypothesis, reaction times (RTs) and latencies of event-related potential have been shown to be moderately associated with intelligence. These associations have been explained either in terms of individual differences in some brain-wide property such as myelination, the speed of neural oscillations, or white-matter tract integrity, or in terms of individual differences in specific processes such as the signal-to-noise ratio in evidence accumulation, executive control, or the cholinergic system. Here we show in a sample of 122 participants, who completed a battery of RT tasks at 2 laboratory sessions while an EEG was recorded, that more intelligent individuals have a higher speed of higher-order information processing that explains about 80% of the variance in general intelligence. Our results do not support the notion that individuals with higher levels of general intelligence show advantages in some brain-wide property. Instead, they suggest that more intelligent individuals benefit from a more efficient transmission of information from frontal attention and working memory processes to temporal-parietal processes of memory storage. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Breastfeeding education and support for women with twins or higher order multiples.

PubMed

Whitford, Heather M; Wallis, Selina K; Dowswell, Therese; West, Helen M; Renfrew, Mary J

2017-02-28

There are rising rates of multiple births worldwide with associated higher rates of complications and more hospital care, often due to prematurity. While there is strong evidence about the risks of not breastfeeding, rates of breastfeeding in women who have given birth to more than one infant are lower than with singleton births. Breastfeeding more than one infant can be more challenging because of difficulties associated with the birth or prematurity. The extra demands on the mother of frequent suckling, coordinating the needs of more than one infant or admission to the neonatal intensive care unit can lead to delayed initiation or early cessation. Additional options such as breast milk expression, the use of donor milk or different methods of supplementary feeding may be considered. Support and education about breastfeeding has been found to improve the duration of any breastfeeding for healthy term infants and their mothers, however evidence is lacking about interventions that are effective to support women with twins or higher order multiples. To assess effectiveness of breastfeeding education and support for women with twins or higher order multiples. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 June 2016), ClinicalTrials.gov (30 June 2016), the WHO International Clinical Trials Registry Platform (ICTRP) (1 July 2016), the excluded studies list from the equivalent Cochrane review of singletons, and reference lists of retrieved studies. Randomised or quasi-randomised trials comparing extra education or support for women with twins or higher order multiples were included. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We planned to assess the quality of evidence using the GRADE approach, but were unable to analyse any data. We found 10 trials (23 reports) of education and support for breastfeeding that included women with twins or higher order multiples. The quality of evidence was mixed, and the risk of bias was mostly high or unclear. It is difficult to blind women or staff to group allocation for this intervention, so in all studies there was high risk of performance and high or unclear risk of detection bias. Trials recruited 5787 women (this included 512 women interviewed as part of a cluster randomised trial); of these, data were available from two studies for 42 women with twins or higher order multiples. None of the interventions were specifically designed for women with more than one infant, and the outcomes for multiples were not reported separately for each infant. Due to the scarcity of evidence and the format in which data were reported, a narrative description of the data is presented, no analyses are presented in this review, and we were unable to GRADE the evidence.The two trials with data for women with multiple births compared home nurse visits versus usual care (15 women), and telephone peer counselling versus usual care (27 women). The number of women who initiated breastfeeding was reported (all 15 women in one study, 25 out of 27 women in one study). Stopping any breastfeeding before four to six weeks postpartum, stopping exclusive breastfeeding before four to six weeks postpartum, stopping any breastfeeding before six months postpartum andstopping exclusive breastfeeding before six months postpartum were not explicitly reported, and there were insufficient data to draw any meaningful conclusions from survival data. Stopping breast milk expression before four to six weeks postpartum, andstopping breast milk expression before six months postpartum were not reported. Measures ofmaternal satisfaction were reported in one study of 15 women, but there were insufficient data to draw any conclusions; no other secondary outcomes were reported for women with multiple births in either study. No adverse events were reported. We found no evidence from randomised controlled trials about the effectiveness of breastfeeding education and support for women with twins or higher order multiples, or the most effective way to provide education and support . There was no evidence about the best way to deliver the intervention, the timing of care, or the best person to deliver the care. There is a need for well-designed, adequately powered studies of interventions designed for women with twins or higher order multiples to find out what types of education and support are effective in helping these mothers to breastfeed their babies.

Modelling the isometric force response to multiple pulse stimuli in locust skeletal muscle.

PubMed

Wilson, Emma; Rustighi, Emiliano; Mace, Brian R; Newland, Philip L

2011-02-01

An improved model of locust skeletal muscle will inform on the general behaviour of invertebrate and mammalian muscle with the eventual aim of improving biomedical models of human muscles, embracing prosthetic construction and muscle therapy. In this article, the isometric response of the locust hind leg extensor muscle to input pulse trains is investigated. Experimental data was collected by stimulating the muscle directly and measuring the force at the tibia. The responses to constant frequency stimulus trains of various frequencies and number of pulses were decomposed into the response to each individual stimulus. Each individual pulse response was then fitted to a model, it being assumed that the response to each pulse could be approximated as an impulse response and was linear, no assumption were made about the model order. When the interpulse frequency (IPF) was low and the number of pulses in the train small, a second-order model provided a good fit to each pulse. For moderate IPF or for long pulse trains a linear third-order model provided a better fit to the response to each pulse. The fit using a second-order model deteriorated with increasing IPF. When the input comprised higher IPFs with a large number of pulses the assumptions that the response was linear could not be confirmed. A generalised model is also presented. This model is second-order, and contains two nonlinear terms. The model is able to capture the force response to a range of inputs. This includes cases where the input comprised of higher frequency pulse trains and the assumption of quasi-linear behaviour could not be confirmed.

Preliminary Planar Formation: Flight Dynamics Near Sun-Earth L2 Point

NASA Technical Reports Server (NTRS)

Segerman, Alan M.; Zedd, Michael F.

2003-01-01

NASA's Goddard Space Flight Center is planning a series of missions in the vicinity of the Sun-Earth L2 libration point. Some of these projects will involve a distributed space system of telescope spacecraft acting together as a single telescope for high-resolution. The individual telescopes will be configured in a plane, surrounding a hub, where the telescope plane can be aimed toward various astronomical targets of interest. In preparation for these missions, it is necessary to develop an improved understanding of the dynamical behavior of objects in a planar configuration near L2. The classical circular restricted three body problem is taken as the basis for the analysis. At first order, the motion of such a telescope relative to the hub is described by a system of linear second order differential equations. These equations are identical to the circular restricted problem's linear equations describing the hub motion about L2. Therefore, the fundamental frequencies, both parallel to and normal to the ecliptic plane, are the same for the relative telescope motion as for the hub motion. To maintain the telescope plane for the duration necessary for the planned observations, a halo-type orbit of the telescopes about the hub is investigated. By using a halo orbit, the individual telescopes remain in approximately the same plane over the observation duration. For such an orbit, the fundamental periods parallel to and normal to the ecliptic plane are forced to be the same by careful selection of the initial conditions in order to adjust the higher order forces. The relative amplitudes of the resulting oscillations are associated with the orientation of the telescope plane relative to the ecliptic. As in the circular restricted problem, initial conditions for the linearized equations must be selected so as not to excite the convergent or divergent linear modes. In a higher order analysis, the telescope relative motion equations include the effects of the position of the hub relative to L2. In this paper, the differential equations are developed through second order in the distance of the hub from the libration point. A modified Lindstedt-Poincad perturbation method is employed to construct the solution of these differential equations through that same order of magnitude. In the course of the solution process, relationships are determined between the initial conditions of the telescopes, selected in order to avoid resonance excitation. As the differential equations include the hub position, it is necessary to simultaneously develop the solution for the hub. As has been done in past analyses of the circular restricted problem, the hub position is written in a power series formulation in terms of its distance from L2. Then, in order to be included in the telescope equations, the hub solution is cast in terms of the nonlinear frequency of the relative telescope motion. In the course of the analysis, it is determined that the hub should also maintain a halo orbit - about L2. Additionally, relationships are formed between the initial conditions of the telescopes and the hub. These relationships may be used to associate sets of initial conditions with particular orientations of the telescope plane. The accuracy of the analytical solution is verified through various simulations and comparison to numerical integration of the differential equations. The results of the simulations are presented, along with a graphical representation of the relationships between the initial conditions of the telescopes and hub.

Magnifying Lenses with Weak Achromatic Bends for High-Energy Electron Radiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walstrom, Peter Lowell

2015-02-27

This memo briefly describes bremsstrahlung background effects in GeV-range electron radiography systems and the use of weak bending magnets to deflect the image to the side of the forward bremsstrahlung spot to reduce background. The image deflection introduces first-order chromatic image blur due to dispersion. Two approaches to eliminating the dispersion effect to first order by use of magnifying lens with achromatic bends are described. Also, higher-order image blur terms caused by weak bends are also discussed, and shown to be negligibly small in most cases of interest.

Teaching mothers to read: evidence from Colombia on the key role of maternal education in preschool child nutritional health.

PubMed

Lomperis, A M

1991-10-01

The determinants of the severity of childhood malnutrition among a low income population in Cali, Colombia in 1974-76 were examined. Sections are devoted to the welfare maximization and household production model and methodology, the data set, the empirical results, the policy implications, and conclusions. The nutritional health of each preschooler is produced within the household with goods and time inputs (food, environmental sanitation, medical care, time invested in child care, and breastfeeding), and is conditioned by the state of household production technology (mother's literacy as a dummy variable -- version 1, and mother's level of schooling -- version 2) as well as by each child's sex, birth order, age, household size, and sociocultural setting. Constraints are total available income and time available (dummy variable). Reinhardt's version of the translog function is used to represent the production process. Household survey data were made available from a pilot study of a maternal and child health program (PRIMOPS) and includes 421 preschool children and 280 households, and food expenditure data for 197 children and 123 households. The main finding is that teaching Third World mothers to read holds the greatest promise of permanently improving the nutritional status of preschool children. The linear regression results show that the determinants of short-term nutritional status as reflected in weight for age (w/a) are the duration of breastfeeding, literacy, 1-3 years of schooling, and the available food in the household. The levels of significance are higher for version 2, but significance is achieved only with the lower levels of schooling. Birth order is statistically significant but weak and negative; i.e., higher birth orders are at higher risk of malnutrition. Long-term nutritional status is statistically significantly influenced by educational level, birth order, and food available, where older preschoolers are likely to experience stunting but not necessarily wasting. The last born suffers the most nutritionally. The proportion of time spent in child rearing vs. employment results needs further clarification. Breastfeeding effects are largely short term. Of the factors affecting children's nutritional status, the data show that food transfer approaches are not the most cost-effective means for solving chronic malnutrition. Implementing literacy programs would be a more successful strategy and lasts a lifetime. Breastfeeding must be for at least 4 months and preferably a year to show a significant improvement in nutrition, and does not eliminate the risk of malnutrition. Smaller families produce healthier children. A mother, who works part time or greater, increases income potential to provide for nutritional need; income and other factors such as literacy are critical determinants of preschool nutritional well being as supported by the findings of Wolfe and Behrman.

[The EMECAM protocol: an analysis of the short-term effect of air pollution on mortality. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica u la Mortalidad].

PubMed

Pérez-Hoyos, S; Sáez Zafra, M; Barceló, M A; Cambra, C; Figueiras Guzmán, A; Ordóñez, J M; Guillén Grima, F; Ocaña, R; Bellido, J; Cirera Suárez, L; López, A A; Rodríguez, V; Alcalá Nalvaiz, T; Ballester Díez, F

1999-01-01

The aim of this study is to Mortality show the protocol of analysis which was set out as part of the EMECAM Project, illustrating the application thereof to the effect of pollution has on the mortality in the city of Valencia. The response variables considered will be the daily deaths rate resulting from all causes, except external ones. The explicative variables are the daily series of different pollutants (black smoke, SO2, NO2, CO, O3). As possible confusion variables, weather factors, structural factors and weekly cases of flu are taken into account. A Poisson regression model is built up for each one of the four deaths series in two stages. In the first stage, a baseline model is fitted using the possible confusion variables. In the second stage, the pollution variables or the time legs thereof are included, controlling the residual autocorrelation by including mortality time lags. The process of fitting the baseline model is as follows: 1) Include the significant sinusoidal terms up to the sixth order. 2) Include the significant temperature or temperature squared terms with the time lags thereof up to the 7th order. 3) Repeat this process with the relative humidity. 4) Add in the significant terms of calendar years, daily tendency and tendency squared. 5) The days of the week as dummy variables are always included in the model. 6) Include the holidays and the significant time lags of up to two weeks of flu. Following the reassessment of the model, each one of the pollutants and the time lags thereof up to the fifth order are proven out. The impact is analyzed by six-month periods, including interaction terms.

Applications of Cosmological Perturbation Theory

NASA Astrophysics Data System (ADS)

Christopherson, Adam J.

2011-06-01

Cosmological perturbation theory is crucial for our understanding of the universe. The linear theory has been well understood for some time, however developing and applying the theory beyond linear order is currently at the forefront of research in theoretical cosmology. This thesis studies the applications of perturbation theory to cosmology and, specifically, to the early universe. Starting with some background material introducing the well-tested 'standard model' of cosmology, we move on to develop the formalism for perturbation theory up to second order giving evolution equations for all types of scalar, vector and tensor perturbations, both in gauge dependent and gauge invariant form. We then move on to the main result of the thesis, showing that, at second order in perturbation theory, vorticity is sourced by a coupling term quadratic in energy density and entropy perturbations. This source term implies a qualitative difference to linear order. Thus, while at linear order vorticity decays with the expansion of the universe, the same is not true at higher orders. This will have important implications on future measurements of the polarisation of the Cosmic Microwave Background, and could give rise to the generation of a primordial seed magnetic field. Having derived this qualitative result, we then estimate the scale dependence and magnitude of the vorticity power spectrum, finding, for simple power law inputs a small, blue spectrum. The final part of this thesis concerns higher order perturbation theory, deriving, for the first time, the metric tensor, gauge transformation rules and governing equations for fully general third order perturbations. We close with a discussion of natural extensions to this work and other possible ideas for off-shooting projects in this continually growing field.

An efficient and accurate two-stage fourth-order gas-kinetic scheme for the Euler and Navier-Stokes equations

NASA Astrophysics Data System (ADS)

Pan, Liang; Xu, Kun; Li, Qibing; Li, Jiequan

2016-12-01

For computational fluid dynamics (CFD), the generalized Riemann problem (GRP) solver and the second-order gas-kinetic scheme (GKS) provide a time-accurate flux function starting from a discontinuous piecewise linear flow distributions around a cell interface. With the adoption of time derivative of the flux function, a two-stage Lax-Wendroff-type (L-W for short) time stepping method has been recently proposed in the design of a fourth-order time accurate method for inviscid flow [21]. In this paper, based on the same time-stepping method and the second-order GKS flux function [42], a fourth-order gas-kinetic scheme is constructed for the Euler and Navier-Stokes (NS) equations. In comparison with the formal one-stage time-stepping third-order gas-kinetic solver [24], the current fourth-order method not only reduces the complexity of the flux function, but also improves the accuracy of the scheme. In terms of the computational cost, a two-dimensional third-order GKS flux function takes about six times of the computational time of a second-order GKS flux function. However, a fifth-order WENO reconstruction may take more than ten times of the computational cost of a second-order GKS flux function. Therefore, it is fully legitimate to develop a two-stage fourth order time accurate method (two reconstruction) instead of standard four stage fourth-order Runge-Kutta method (four reconstruction). Most importantly, the robustness of the fourth-order GKS is as good as the second-order one. In the current computational fluid dynamics (CFD) research, it is still a difficult problem to extend the higher-order Euler solver to the NS one due to the change of governing equations from hyperbolic to parabolic type and the initial interface discontinuity. This problem remains distinctively for the hypersonic viscous and heat conducting flow. The GKS is based on the kinetic equation with the hyperbolic transport and the relaxation source term. The time-dependent GKS flux function provides a dynamic process of evolution from the kinetic scale particle free transport to the hydrodynamic scale wave propagation, which provides the physics for the non-equilibrium numerical shock structure construction to the near equilibrium NS solution. As a result, with the implementation of the fifth-order WENO initial reconstruction, in the smooth region the current two-stage GKS provides an accuracy of O ((Δx) 5 ,(Δt) 4) for the Euler equations, and O ((Δx) 5 ,τ2 Δt) for the NS equations, where τ is the time between particle collisions. Many numerical tests, including difficult ones for the Navier-Stokes solvers, have been used to validate the current method. Perfect numerical solutions can be obtained from the high Reynolds number boundary layer to the hypersonic viscous heat conducting flow. Following the two-stage time-stepping framework, the third-order GKS flux function can be used as well to construct a fifth-order method with the usage of both first-order and second-order time derivatives of the flux function. The use of time-accurate flux function may have great advantages on the development of higher-order CFD methods.

The third order correction on Hawking radiation and entropy conservation during black hole evaporation process

NASA Astrophysics Data System (ADS)

Yan, Hao-Peng; Liu, Wen-Biao

2016-08-01

Using Parikh-Wilczek tunneling framework, we calculate the tunneling rate from a Schwarzschild black hole under the third order WKB approximation, and then obtain the expressions for emission spectrum and black hole entropy to the third order correction. The entropy contains four terms including the Bekenstein-Hawking entropy, the logarithmic term, the inverse area term, and the square of inverse area term. In addition, we analyse the correlation between sequential emissions under this approximation. It is shown that the entropy is conserved during the process of black hole evaporation, which consists with the request of quantum mechanics and implies the information is conserved during this process. We also compare the above result with that of pure thermal spectrum case, and find that the non-thermal correction played an important role.

Solute boundary layer on a rotating crystal

NASA Astrophysics Data System (ADS)

Povinelli, Michelle L.; Korpela, Seppo A.; Chait, Arnon

1994-11-01

A perturbation analysis has been carried out for the solutal boundary layer next to a rotating crystal. Our aim is to extend the classical results of Burton, Prim and Slicher [1] in order to obtain higher order terms in asymptotic expansions for the concentration field and boundary-layer thickness. Expressions for the effective segregation coefficient are directly obtained from the concentration solution in the two limits that correspond to weak and strong rotation.

Chirped solitary pulses for a nonic nonlinear Schrödinger equation on a continuous-wave background

NASA Astrophysics Data System (ADS)

Triki, Houria; Porsezian, K.; Choudhuri, Amitava; Dinda, P. Tchofo

2016-06-01

A class of derivative nonlinear Schrödinger equation with cubic-quintic-septic-nonic nonlinear terms describing the propagation of ultrashort optical pulses through a nonlinear medium with higher-order Kerr responses is investigated. An intensity-dependent chirp ansatz is adopted for solving the two coupled amplitude-phase nonlinear equations of the propagating wave. We find that the dynamics of field amplitude in this system is governed by a first-order nonlinear ordinary differential equation with a tenth-degree nonlinear term. We demonstrate that this system allows the propagation of a very rich variety of solitary waves (kink, dark, bright, and gray solitary pulses) which do not coexist in the conventional nonlinear systems that have appeared so far in the literature. The stability of the solitary wave solution under some violation on the parametric conditions is investigated. Moreover, we show that, unlike conventional systems, the nonlinear Schrödinger equation considered here meets the special requirements for the propagation of a chirped solitary wave on a continuous-wave background, involving a balance among group velocity dispersion, self-steepening, and higher-order nonlinearities of different nature.

Hamilton-Jacobi modelling of relative motion for formation flying.

PubMed

Kolemen, Egemen; Kasdin, N Jeremy; Gurfil, Pini

2005-12-01

A precise analytic model for the relative motion of a group of satellites in slightly elliptic orbits is introduced. With this aim, we describe the relative motion of an object relative to a circular or slightly elliptic reference orbit in the rotating Hill frame via a low-order Hamiltonian, and solve the Hamilton-Jacobi equation. This results in a first-order solution to the relative motion identical to the Clohessy-Wiltshire approach; here, however, rather than using initial conditions as our constants of the motion, we utilize the canonical momenta and coordinates. This allows us to treat perturbations in an identical manner, as in the classical Delaunay formulation of the two-body problem. A precise analytical model for the base orbit is chosen with the included effect of zonal harmonics (J(2), J(3), J(4)). A Hamiltonian describing the real relative motion is formed and by differing this from the nominal Hamiltonian, the perturbing Hamiltonian is obtained. Using the Hamilton equations, the variational equations for the new constants are found. In a manner analogous to the center manifold reduction procedure, the non-periodic part of the motion is canceled through a magnitude analysis leading to simple boundedness conditions that cancel the drift terms due to the higher order perturbations. Using this condition, the variational equations are integrated to give periodic solutions that closely approximate the results from numerical integration (1 mm/per orbit for higher order and eccentricity perturbations and 30 cm/per orbit for zonal perturbations). This procedure provides a compact and insightful analytic description of the resulting relative motion.

Higher Curvature Gravity from Entanglement in Conformal Field Theories.

PubMed

Haehl, Felix M; Hijano, Eliot; Parrikar, Onkar; Rabideau, Charles

2018-05-18

By generalizing different recent works to the context of higher curvature gravity, we provide a unifying framework for three related results: (i) If an asymptotically anti-de Sitter (AdS) spacetime computes the entanglement entropies of ball-shaped regions in a conformal field theory using a generalized Ryu-Takayanagi formula up to second order in state deformations around the vacuum, then the spacetime satisfies the correct gravitational equations of motion up to second order around the AdS background. (ii) The holographic dual of entanglement entropy in higher curvature theories of gravity is given by the Wald entropy plus a particular correction term involving extrinsic curvatures. (iii) Conformal field theory relative entropy is dual to gravitational canonical energy (also in higher curvature theories of gravity). Especially for the second point, our novel derivation of this previously known statement does not involve the Euclidean replica trick.

Higher Curvature Gravity from Entanglement in Conformal Field Theories

NASA Astrophysics Data System (ADS)

Haehl, Felix M.; Hijano, Eliot; Parrikar, Onkar; Rabideau, Charles

2018-05-01

By generalizing different recent works to the context of higher curvature gravity, we provide a unifying framework for three related results: (i) If an asymptotically anti-de Sitter (AdS) spacetime computes the entanglement entropies of ball-shaped regions in a conformal field theory using a generalized Ryu-Takayanagi formula up to second order in state deformations around the vacuum, then the spacetime satisfies the correct gravitational equations of motion up to second order around the AdS background. (ii) The holographic dual of entanglement entropy in higher curvature theories of gravity is given by the Wald entropy plus a particular correction term involving extrinsic curvatures. (iii) Conformal field theory relative entropy is dual to gravitational canonical energy (also in higher curvature theories of gravity). Especially for the second point, our novel derivation of this previously known statement does not involve the Euclidean replica trick.

Conformal supergravity in five dimensions: new approach and applications

NASA Astrophysics Data System (ADS)

Butter, Daniel; Kuzenko, Sergei M.; Novak, Joseph; Tartaglino-Mazzucchelli, Gabriele

2015-02-01

We develop a new off-shell formulation for five-dimensional (5D) conformal supergravity obtained by gauging the 5D superconformal algebra in superspace. An important property of the conformal superspace introduced is that it reduces to the super-conformal tensor calculus (formulated in the early 2000's) upon gauging away a number of superfluous fields. On the other hand, a different gauge fixing reduces our formulation to the SU(2) superspace of arXiv:0802.3953, which is suitable to describe the most general off-shell supergravity-matter couplings. Using the conformal superspace approach, we show how to reproduce practically all off-shell constructions derived so far, including he supersymmetric extensions of R 2 terms, thus demonstrating the power of our formulation. Furthermore, we construct for the first time a supersymmetric completion of the Ricci tensor squared term using the standard Weyl multiplet coupled to an off-shell vector multiplet. In addition, we present several procedures to generate higher-order off-shell invariants in supergravity, including higher-derivative ones. The covariant projective multiplets proposed in arXiv:0802.3953 are lifted to conformal superspace, and a manifestly superconformal action principle is given. We also introduce unconstrained prepotentials for the vector multiplet, the multiplet (i.e., the linear multiplet without central charge) and multiplets, with n = 0 , 1 , . . . Superform formulations are given for the BF action and the non-abelian Chern-Simons action. Finally, we describe locally supersymmetric theories with gauged central charge in conformal superspace.

Planck 2015 results. XXII. A map of the thermal Sunyaev-Zeldovich effect

NASA Astrophysics Data System (ADS)

Planck Collaboration; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Battaner, E.; Battye, R.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chiang, H. C.; Christensen, P. R.; Churazov, E.; Clements, D. L.; Colombo, L. P. L.; Combet, C.; Comis, B.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Génova-Santos, R. T.; Giard, M.; González-Nuevo, J.; Górski, K. M.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Harrison, D. L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Holmes, W. A.; Hornstrup, A.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lacasa, F.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Macías-Pérez, J. F.; Maffei, B.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Melchiorri, A.; Melin, J.-B.; Migliaccio, M.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Noviello, F.; Novikov, D.; Novikov, I.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Pratt, G. W.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rossetti, M.; Roudier, G.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Sauvé, A.; Savelainen, M.; Savini, G.; Scott, D.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tramonte, D.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; Yvon, D.; Zacchei, A.; Zonca, A.

2016-09-01

We have constructed all-sky Compton parameters maps, y-maps, of the thermal Sunyaev-Zeldovich (tSZ) effect by applying specifically tailored component separation algorithms to the 30 to 857 GHz frequency channel maps from the Planck satellite. These reconstructed y-maps are delivered as part of the Planck 2015 release. The y-maps are characterized in terms of noise properties and residual foreground contamination, mainly thermal dust emission at large angular scales, and cosmic infrared background and extragalactic point sources at small angular scales. Specific masks are defined to minimize foreground residuals and systematics. Using these masks, we compute the y-map angular power spectrum and higher order statistics. From these we conclude that the y-map is dominated by tSZ signal in the multipole range, 20 <ℓ< 600. We compare the measured tSZ power spectrum and higher order statistics to various physically motivated models and discuss the implications of our results in terms of cluster physics and cosmology.

Filtering of higher-order laser modes using plasma structures

NASA Astrophysics Data System (ADS)

Djordjevic, Blagoje; Benedetti, Carlo; Schroeder, Carl; Esarey, Eric; Leemans, Wim

2017-10-01

Plasma structures based on leaky channels are proposed to filter higher-order laser mode content. The evolution and propagation of non-Gaussian laser pulses in leaky channels is studied, and it is shown that, for appropriate laser-plasma parameters, the higher-order laser mode content may be removed while the fundamental mode remains well-guided. The behavior of the multi-mode laser pulse is described analytically, including the derivation of the leakage coefficients, and compared to numerical calculations. Gaussian laser pulse propagation, without higher-order mode content, improves guiding in parabolic plasma channels, enabling extended interaction lengths for laser-plasma accelerator applications. This work was supported by the Director, Office of Science, Office of High Energy Physics, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Analysis of FORTE data to extract ionospheric parameters

NASA Astrophysics Data System (ADS)

Roussel-Dupré, Robert A.; Jacobson, Abram R.; Triplett, Laurie A.

2001-01-01

The ionospheric transfer function is derived for a spherically symmetric ionosphere with an arbitrary radial electron density profile in the limit where the radio frequencies of interest ω are much larger than the plasma frequency ωpe. An expansion of the transfer function to second order in the parameter X (= ω2pe/ω2) is carried out. In this limit the dispersive properties of the ionosphere are manifested as a frequency-dependent time of arrival that includes quadratic, cubic, and quartic terms in 1/ω. The coefficients of these terms are related to the total electron content (TEC) along the slant path from transmitter to receiver, the product of TEC and the longitudinal magnetic field strength along the slant path, and refractive bending and higher-order electron density profile effects, respectively. By fitting the time of arrival versus frequency of a transionospheric signal to a polynomial in 1/ω it is possible to extract the TEC, the longitudinal magnetic field strength, the peak electron density, and an effective thickness for the ionosphere. This exercise was carried out for a number of transionospheric pulses measured in the VHF by the FORTE satellite receiver and generated by the Los Alamos Portable Pulser. The results are compared with predictions derived from the International Reference Ionosphere and the United States Geological Survey geomagnetic field model.

Estimating the welfare loss to households from natural disasters in developing countries: a contingent valuation study of flooding in Vietnam

PubMed Central

Navrud, Ståle; Tuan, Tran Huu; Tinh, Bui Duc

2012-01-01

Background Natural disasters have severe impacts on the health and well-being of affected households. However, we find evidence that official damage cost assessments for floods and other natural disasters in Vietnam, where households have little or no insurance, clearly underestimate the total economic damage costs of these events as they do not include the welfare loss from mortality, morbidity and well-being experienced by the households affected by the floods. This should send a message to the local communities and national authorities that higher investments in flood alleviation, reduction and adaptive measures can be justified since the social benefits of these measures in terms of avoided damage costs are higher than previously thought. Methods We pioneer the use of the contingent valuation (CV) approach of willingness-to-contribute (WTC) labour to a flood prevention program, as a measure of the welfare loss experienced by household due to a flooding event. In a face-to-face household survey of 706 households in the Quang Nam province in Central Vietnam, we applied this approach together with reported direct physical damage in order to shed light of the welfare loss experienced by the households. We asked about households’ WTC labour and multiplied their WTC person-days of labour by an estimate for their opportunity cost of time in order to estimate the welfare loss to households from the 2007 floods. Results The results showed that this contingent valuation (CV) approach of asking about willingness-to-pay in-kind avoided the main problems associated with applying CV in developing countries. Conclusion Thus, the CV approach of WTC labour instead of money is promising in terms of capturing the total welfare loss of natural disasters, and promising in terms of further application in other developing countries and for other types of natural disasters. PMID:22761603

Estimating the welfare loss to households from natural disasters in developing countries: a contingent valuation study of flooding in Vietnam.

PubMed

Navrud, Ståle; Tuan, Tran Huu; Tinh, Bui Duc

2012-01-01

Natural disasters have severe impacts on the health and well-being of affected households. However, we find evidence that official damage cost assessments for floods and other natural disasters in Vietnam, where households have little or no insurance, clearly underestimate the total economic damage costs of these events as they do not include the welfare loss from mortality, morbidity and well-being experienced by the households affected by the floods. This should send a message to the local communities and national authorities that higher investments in flood alleviation, reduction and adaptive measures can be justified since the social benefits of these measures in terms of avoided damage costs are higher than previously thought. We pioneer the use of the contingent valuation (CV) approach of willingness-to-contribute (WTC) labour to a flood prevention program, as a measure of the welfare loss experienced by household due to a flooding event. In a face-to-face household survey of 706 households in the Quang Nam province in Central Vietnam, we applied this approach together with reported direct physical damage in order to shed light of the welfare loss experienced by the households. We asked about households' WTC labour and multiplied their WTC person-days of labour by an estimate for their opportunity cost of time in order to estimate the welfare loss to households from the 2007 floods. The results showed that this contingent valuation (CV) approach of asking about willingness-to-pay in-kind avoided the main problems associated with applying CV in developing countries. Thus, the CV approach of WTC labour instead of money is promising in terms of capturing the total welfare loss of natural disasters, and promising in terms of further application in other developing countries and for other types of natural disasters.

Modulation stability and optical soliton solutions of nonlinear Schrödinger equation with higher order dispersion and nonlinear terms and its applications

NASA Astrophysics Data System (ADS)

Arshad, Muhammad; Seadawy, Aly R.; Lu, Dianchen

2017-12-01

In optical fibers, the higher order non-linear Schrödinger equation (NLSE) with cubic quintic nonlinearity describes the propagation of extremely short pulses. We constructed bright and dark solitons, solitary wave and periodic solitary wave solutions of generalized higher order NLSE in cubic quintic non Kerr medium by applying proposed modified extended mapping method. These obtained solutions have key applications in physics and mathematics. Moreover, we have also presented the formation conditions on solitary wave parameters in which dark and bright solitons can exist for this media. We also gave graphically the movement of constructed solitary wave and soliton solutions, that helps to realize the physical phenomena's of this model. The stability of the model in normal dispersion and anomalous regime is discussed by using the modulation instability analysis, which confirms that all constructed solutions are exact and stable. Many other such types of models arising in applied sciences can also be solved by this reliable, powerful and effective method.

Optical quasi-soliton solutions for higher-order nonlinear Schrödinger equation with variable coefficients

NASA Astrophysics Data System (ADS)

Zhang, Jiefang; Yang, Qin; Dai, Chaoqing

2005-04-01

Optical quasi-soliton solutions for higher-order nonlinear Schrödinger equation (HNLS) with variable coefficients are considered. Based on the extended tanh-function method, we successfully obtained bright and dark quasi-soliton solutions under certain parametric conditions. We conclude that the parameter k(z) is unnecessary to be zero compared with [R. Yang et al., Opt. Commun. 242 (2004) 285]. Furthermore, we choose appropriate optical fiber parameters D2(z) and D3(z) to control the velocity of quasi-soliton and time shift, and discuss the evolution behavior of the special quasi-soliton. For D3(z) = α(z) = f(z) = 0, that is to say, under the absence of the higher order terms, we give same results as early reported in [R.Y. Hao, L. Li, Z.H. Li, W.R. Xue, G.S. Zhou, Opt. Commun. 236 (2004) 79]. As discussed examples, we also analyze three optical systems with real physical significance and obtain results which can be recovered in earlier papers.

Josephson parametric converter saturation and higher order effects

NASA Astrophysics Data System (ADS)

Liu, G.; Chien, T.-C.; Cao, X.; Lanes, O.; Alpern, E.; Pekker, D.; Hatridge, M.

2017-11-01

Microwave parametric amplifiers based on Josephson junctions have become indispensable components of many quantum information experiments. One key limitation which has not been well predicted by theory is the gain saturation behavior which limits the amplifier's ability to process large amplitude signals. The typical explanation for this behavior in phase-preserving amplifiers based on three-wave mixing, such as the Josephson Parametric Converter, is pump depletion, in which the consumption of pump photons to produce amplification results in a reduction in gain. However, in this work, we present experimental data and theoretical calculations showing that the fourth-order Kerr nonlinearities inherent in Josephson junctions are the dominant factor. The Kerr-based theory has the unusual property of causing saturation to both lower and higher gains, depending on bias conditions. This work presents an efficient methodology for optimizing device performance in the presence of Kerr nonlinearities while retaining device tunability and points to the necessity of controlling higher-order Hamiltonian terms to make further improvements in parametric devices.

Engaging adolescents with LD in higher order thinking about history concepts using integrated content enhancement routines.

PubMed

Bulgren, Janis; Deshler, Donald D; Lenz, B Keith

2007-01-01

The understanding and use of historical concepts specified in national history standards pose many challenges to students. These challenges include both the acquisition of content knowledge and the use of that knowledge in ways that require higher order thinking. All students, including adolescents with learning disabilities (LD), are expected to understand and use concepts of history to pass high-stakes assessments and to participate meaningfully in a democratic society. This article describes Content Enhancement Routines (CERs) to illustrate instructional planning, teaching, and assessing for higher order thinking with examples from an American history unit. Research on the individual components of Content Enhancement Routines will be illustrated with data from 1 of the routines. The potential use of integrated sets of materials and procedures across grade levels and content areas will be discussed.

Generalized quantum kinetic expansion: Higher-order corrections to multichromophoric Förster theory

NASA Astrophysics Data System (ADS)

Wu, Jianlan; Gong, Zhihao; Tang, Zhoufei

2015-08-01

For a general two-cluster energy transfer network, a new methodology of the generalized quantum kinetic expansion (GQKE) method is developed, which predicts an exact time-convolution equation for the cluster population evolution under the initial condition of the local cluster equilibrium state. The cluster-to-cluster rate kernel is expanded over the inter-cluster couplings. The lowest second-order GQKE rate recovers the multichromophoric Förster theory (MCFT) rate. The higher-order corrections to the MCFT rate are systematically included using the continued fraction resummation form, resulting in the resummed GQKE method. The reliability of the GQKE methodology is verified in two model systems, revealing the relevance of higher-order corrections.

SVP-like MADS-box protein from Carya cathayensis forms higher-order complexes.

PubMed

Wang, Jingjing; Hou, Chuanming; Huang, Jianqin; Wang, Zhengjia; Xu, Yingwu

2015-03-01

To properly regulate plant flowering time and construct floral pattern, MADS-domain containing transcription factors must form multimers including homo- and hetero-dimers. They are also active in forming hetero-higher-order complexes with three to five different molecules. However, it is not well known if a MADS-box protein can also form homo-higher-order complex. In this study a biochemical approach is utilized to provide insight into the complex formation for an SVP-like MADS-box protein cloned from hickory. The results indicated that the protein is a heterogeneous higher-order complex with the peak population containing over 20 monomers. Y2H verified the protein to form homo-complex in yeast cells. Western blot of the hickory floral bud sample revealed that the protein exists in higher-order polymers in native. Deletion assays indicated that the flexible C-terminal residues are mainly responsible for the higher-order polymer formation and the heterogeneity. Current results provide direct biochemical evidences for an active MADS-box protein to be a high order complex, much higher than a quartermeric polymer. Analysis suggests that a MADS-box subset may be able to self-assemble into large complexes, and thereby differentiate one subfamily from the other in a higher-order structural manner. Present result is a valuable supplement to the action of mechanism for MADS-box proteins in plant development. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Higher order acoustoelastic Lamb wave propagation in stressed plates.

PubMed

Pei, Ning; Bond, Leonard J

2016-11-01

Modeling and experiments are used to investigate Lamb wave propagation in the direction perpendicular to an applied stress. Sensitivity, in terms of changes in velocity, for both symmetrical and anti-symmetrical modes was determined. Codes were developed based on analytical expressions for waves in loaded plates and they were used to give wave dispersion curves. The experimental system used a pair of compression wave transducers on variable angle wedges, with set separation, and variable frequency tone burst excitation, on an aluminum plate 0.16 cm thick with uniaxial applied loads. The loads, which were up to 600 με, were measured using strain gages. Model results and experimental data are in good agreement. It was found that the change in Lamb wave velocity, due to the acoustoelastic effect, for the S 1 mode exhibits about ten times more sensitive, in terms of velocity change, than the traditional bulk wave measurements, and those performed using the fundamental Lamb modes. The data presented demonstrate the potential for the use of higher order Lamb modes for online industrial stress measurement in plate, and that the higher sensitivity seen offers potential for improved measurement systems.

Water-waves frequency upshift of the spectral mean due to wind forcing

NASA Astrophysics Data System (ADS)

Eeltink, Debbie; Chabchoub, Amin; Brunetti, Maura; Kasparian, Jerome; Kimmoun, Olivier; Branger, Hubert

2017-04-01

The effect of wind forcing on monochromatic modulated water waves was investigated both numerically and experimentally in the context of the Modified Non-Linear Schrödinger (MNLS) equation framework. While wind is usually associated with a frequency downshift of the dominant spectral peak, we show that it may induce an upshift of the spectral mean due to an asymmetric amplification of the spectrum. Here the weighted average spectral mean is equal to the ratio of the momentum of the envelope to its norm and it detects any asymmetries in the spectrum (Segur et al. 2005). Wind can however indirectly induce frequency downshifts, by promoting dissipative effects like wave breaking. We highlight that the definition of the up- and downshift in terms of peak frequency or average frequency is critical for a relevant discussion. In our model, the wind input consists of a leading order forcing term that amplifies all frequencies equally and induces a broadening of the spectrum, and a higher order asymmetric term (Brunetti et al. 2014; Brunetti & Kasparian 2014) that amplifies higher frequencies more than lower ones and induces a permanent upshift of the spectral mean. The effect of MNLS + wind is exactly opposite to MNLS + viscosity, where the lower order viscosity terms damp the whole spectrum, while the higher order viscosity terms damp higher frequencies more than lower ones and thus causes a permanent downshift, as evidenced by Carter & Govan (2016). We corroborated the model with wave tank experiments conducted in the IRPHE/Pytheas large wind-wave facility located in Marseille, France. Wave data analysis show the temporary downshift in the spectral peak sense caused by the wind, and the temporary upshift in the spectral mean sense characteristic of the MNLS. As the tank-length was limited, we used long-range simulations to obtain upshift in the spectral mean sense caused by the wind. The limit of the model is reached when breaking events occur. We acknowledge financial support from the Swiss National Science Foundation (project 200021-155970), the Labex MEC (French ANR-10-LABX-0092) and the A*MIDEX project (ANR-11-IDEX-0001-02). • Brunetti, M. and Kasparian, J. 2014 "Modulational instability in wind-forced waves". Physics Letters A, 378: 48, 3626-3630. • Brunetti, M., Marchiando, N., Berti, N. and Kasparian, J. 2014 "Nonlinear fast growth of water waves under wind forcing". Physics Letters A 378: 1415, 1025-1030. • Carter, J. D. and Govan, A. 2016 "Frequency downshift in a viscous fluid." Eur. Journ. Mech. - B/Fluids 59: 177-185. • Segur, H., Henderson, D., Carter, J., Hammack, J., Li, C.-M., Pheiff, D. and Socha, K. 2005 "Stabilizing the Benjamin-Feir instability". Journ. Fluid Mechanics, 539: 229-271.

Electron-phonon coupling from finite differences

NASA Astrophysics Data System (ADS)

Monserrat, Bartomeu

2018-02-01

The interaction between electrons and phonons underlies multiple phenomena in physics, chemistry, and materials science. Examples include superconductivity, electronic transport, and the temperature dependence of optical spectra. A first-principles description of electron-phonon coupling enables the study of the above phenomena with accuracy and material specificity, which can be used to understand experiments and to predict novel effects and functionality. In this topical review, we describe the first-principles calculation of electron-phonon coupling from finite differences. The finite differences approach provides several advantages compared to alternative methods, in particular (i) any underlying electronic structure method can be used, and (ii) terms beyond the lowest order in the electron-phonon interaction can be readily incorporated. But these advantages are associated with a large computational cost that has until recently prevented the widespread adoption of this method. We describe some recent advances, including nondiagonal supercells and thermal lines, that resolve these difficulties, and make the calculation of electron-phonon coupling from finite differences a powerful tool. We review multiple applications of the calculation of electron-phonon coupling from finite differences, including the temperature dependence of optical spectra, superconductivity, charge transport, and the role of defects in semiconductors. These examples illustrate the advantages of finite differences, with cases where semilocal density functional theory is not appropriate for the calculation of electron-phonon coupling and many-body methods such as the GW approximation are required, as well as examples in which higher-order terms in the electron-phonon interaction are essential for an accurate description of the relevant phenomena. We expect that the finite difference approach will play a central role in future studies of the electron-phonon interaction.

A Probabilistic Model of Visual Working Memory: Incorporating Higher Order Regularities into Working Memory Capacity Estimates

ERIC Educational Resources Information Center

Brady, Timothy F.; Tenenbaum, Joshua B.

2013-01-01

When remembering a real-world scene, people encode both detailed information about specific objects and higher order information like the overall gist of the scene. However, formal models of change detection, like those used to estimate visual working memory capacity, assume observers encode only a simple memory representation that includes no…

Missing in Action: Writing Process-Based Instructional Practices and Measures of Higher-Order Literacy Achievement in Predominantly Urban Elementary Schools

ERIC Educational Resources Information Center

Briddell, Andrew

2013-01-01

This study of 1,974 fifth grade students investigated potential relationships between writing process-based instruction practices and higher-order thinking measured by a standardized literacy assessment. Writing process is defined as a highly complex, socio-cognitive process that includes: planning, text production, review, metacognition, writing…

Computer Game Development: An Instructional Strategy to Promote Higher Order Thinking Skills

ERIC Educational Resources Information Center

Prayaga, Lakshmi; Coffey, John W.

2008-01-01

Several studies have demonstrated that games have been effectively used as an instructional strategy to motivate and engage students. This paper presents the use of the process of game development as an instructional strategy to promote higher order thinking skills. An analysis of the various aspects of game development including graphics,…

Higher-Order Fertility among Urban Fathers: An Overlooked Issue for a Neglected Population

ERIC Educational Resources Information Center

Bronte-Tinkew, Jacinta; Ryan, Suzanne; Franzetta, Kerry; Manlove, Jennifer; Lilja, Emily

2009-01-01

The study includes a longitudinal sample of 1,989 fathers from the Fragile Families and Child Wellbeing study and examines factors associated with fathering a higher-order birth (three or more children) and compares these factors to those predicting any subsequent birth. Also, the article examines differences by marital status. Logistic regression…

Research on Interventions for Adolescents with Learning Disabilities: A Meta-Analysis of Outcomes Related to Higher-Order Processing.

ERIC Educational Resources Information Center

Swanson, H. Lee

2001-01-01

Details meta-analysis of 58 intervention studies related to higher-order processing (i.e., problem solving) for adolescents with learning disabilities. Discusses factors that increased effect sizes: (1) measures of metacognition and text understanding; (2) instruction including advanced organizers, new skills, and extended practice; and (3)…

Higher Order First Integrals of Motion in a Gauge Covariant Hamiltonian Framework

NASA Astrophysics Data System (ADS)

Visinescu, Mihai

The higher order symmetries are investigated in a covariant Hamiltonian formulation. The covariant phase-space approach is extended to include the presence of external gauge fields and scalar potentials. The special role of the Killing-Yano tensors is pointed out. Some nontrivial examples involving Runge-Lenz type conserved quantities are explicitly worked out.

Orthogonal Higher Order Structure of the WISC-IV Spanish Using Hierarchical Exploratory Factor Analytic Procedures

ERIC Educational Resources Information Center

McGill, Ryan J.; Canivez, Gary L.

2016-01-01

As recommended by Carroll, the present study examined the factor structure of the Wechsler Intelligence Scale for Children-Fourth Edition Spanish (WISC-IV Spanish) normative sample using higher order exploratory factor analytic techniques not included in the WISC-IV Spanish Technical Manual. Results indicated that the WISC-IV Spanish subtests were…

Helping Kids To Probe and Ponder: Integrating Higher Order Thinking into the General Curriculum.

ERIC Educational Resources Information Center

Stratton, Jean A.

This paper addresses issues in integrating higher order thinking into the general curriculum. Data are based on a series of telephone interviews conducted in April and May 1992 with six leading thinkers in educational reform. They included: (1) Michael Apple, John Bascom Professor of Curriculum, Instruction, and Educational Policy Studies at the…

Tracking Skill Acquisition with Cognitive Diagnosis Models: A Higher-Order, Hidden Markov Model with Covariates

ERIC Educational Resources Information Center

Wang, Shiyu; Yang, Yan; Culpepper, Steven Andrew; Douglas, Jeffrey A.

2018-01-01

A family of learning models that integrates a cognitive diagnostic model and a higher-order, hidden Markov model in one framework is proposed. This new framework includes covariates to model skill transition in the learning environment. A Bayesian formulation is adopted to estimate parameters from a learning model. The developed methods are…

Neutron monochromators of BeO, MgO and ZnO single crystals

NASA Astrophysics Data System (ADS)

Adib, M.; Habib, N.; Bashter, I. I.; Morcos, H. N.; El-Mesiry, M. S.; Mansy, M. S.

2014-05-01

The monochromatic features of BeO, MgO and ZnO single crystals are discussed in terms of orientation, mosaic spread, and thickness within the wavelength band from 0.05 up to 0.5 nm. A computer program MONO, written in “FORTRAN”, has been developed to carry out the required calculations. Calculation shows that a 5 mm thick MgO single crystal cut along its (2 0 0) plane having mosaic spread of 0.5° FWHM has the optimum parameters when it is used as a neutron monochromator. Moreover, at wavelengths shorter than 0.24 nm the reflected monochromatic neutrons are almost free from the higher order ones. The same features are seen with BeO (0 0 2) with less reflectivity than that of the former. Also, ZnO cut along its (0 0 2) plane is preferred over the others only at wavelengths longer than 0.20 nm. When the selected monochromatic wavelength is longer than 0.24 nm, the neutron intensities of higher orders from a thermal reactor flux are higher than those of the first-order one. For a cold reactor flux, the first order of BeO and MgO single crystals is free from the higher orders up to 0.4 nm, and ZnO at wavelengths up to 0.5 nm.

Higher-order QCD predictions for dark matter production at the LHC in simplified models with s-channel mediators.

PubMed

Backović, Mihailo; Krämer, Michael; Maltoni, Fabio; Martini, Antony; Mawatari, Kentarou; Pellen, Mathieu

Weakly interacting dark matter particles can be pair-produced at colliders and detected through signatures featuring missing energy in association with either QCD/EW radiation or heavy quarks. In order to constrain the mass and the couplings to standard model particles, accurate and precise predictions for production cross sections and distributions are of prime importance. In this work, we consider various simplified models with s -channel mediators. We implement such models in the FeynRules/MadGraph5_aMC@NLO framework, which allows to include higher-order QCD corrections in realistic simulations and to study their effect systematically. As a first phenomenological application, we present predictions for dark matter production in association with jets and with a top-quark pair at the LHC, at next-to-leading order accuracy in QCD, including matching/merging to parton showers. Our study shows that higher-order QCD corrections to dark matter production via s -channel mediators have a significant impact not only on total production rates, but also on shapes of distributions. We also show that the inclusion of next-to-leading order effects results in a sizeable reduction of the theoretical uncertainties.

SHARP: A Spatially Higher-order, Relativistic Particle-in-cell Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shalaby, Mohamad; Broderick, Avery E.; Chang, Philip

Numerical heating in particle-in-cell (PIC) codes currently precludes the accurate simulation of cold, relativistic plasma over long periods, severely limiting their applications in astrophysical environments. We present a spatially higher-order accurate relativistic PIC algorithm in one spatial dimension, which conserves charge and momentum exactly. We utilize the smoothness implied by the usage of higher-order interpolation functions to achieve a spatially higher-order accurate algorithm (up to the fifth order). We validate our algorithm against several test problems—thermal stability of stationary plasma, stability of linear plasma waves, and two-stream instability in the relativistic and non-relativistic regimes. Comparing our simulations to exact solutionsmore » of the dispersion relations, we demonstrate that SHARP can quantitatively reproduce important kinetic features of the linear regime. Our simulations have a superior ability to control energy non-conservation and avoid numerical heating in comparison to common second-order schemes. We provide a natural definition for convergence of a general PIC algorithm: the complement of physical modes captured by the simulation, i.e., those that lie above the Poisson noise, must grow commensurately with the resolution. This implies that it is necessary to simultaneously increase the number of particles per cell and decrease the cell size. We demonstrate that traditional ways for testing for convergence fail, leading to plateauing of the energy error. This new PIC code enables us to faithfully study the long-term evolution of plasma problems that require absolute control of the energy and momentum conservation.« less

Primordial spectra of slow-roll inflation at second-order with the Gauss-Bonnet correction

NASA Astrophysics Data System (ADS)

Wu, Qiang; Zhu, Tao; Wang, Anzhong

2018-05-01

The slow-roll inflation for a single scalar field that couples to the Gauss-Bonnet (GB) term represents an important higher-order curvature correction inspired by string theory. With the arrival of the era of precision cosmology, it is expected that the high-order corrections become more and more important. In this paper we study the observational predictions of the slow-roll inflation with the GB term by using the third-order uniform asymptotic approximation method. We calculate explicitly the primordial power spectra, spectral indices, running of the spectral indices for both scalar and tensor perturbations, and the ratio between tensor and scalar spectra. These expressions are all written in terms of the Hubble and GB coupling flow parameters and expanded up to the next-to-leading order in the slow-roll expansions so they represent the most accurate results obtained so far in the literature. In addition, by studying the theoretical predictions of the scalar spectral index and the tensor-to-scalar ratio with the Planck 2015 constraints in a model with power-law potential and GB coupling, we show that the second-order corrections are important in the future measurements. We expect that the understanding of the GB corrections in the primordial spectra and their constraints by forthcoming observational data will provide clues for the UV complete theory of quantum gravity, such as the string/M-theory.

Automated parton-shower variations in PYTHIA 8

DOE PAGES

Mrenna, S.; Skands, P.

2016-10-03

In the era of precision physics measurements at the LHC, efficient and exhaustive estimations of theoretical uncertainties play an increasingly crucial role. In the context of Monte Carlo (MC) event generators, the estimation of such uncertainties traditionally requires independent MC runs for each variation, for a linear increase in total run time. In this work, we report on an automated evaluation of the dominant (renormalization-scale and nonsingular) perturbative uncertainties in the pythia 8 event generator, with only a modest computational overhead. Each generated event is accompanied by a vector of alternative weights (one for each uncertainty variation), with each set separatelymore » preserving the total cross section. Explicit scale-compensating terms can be included, reflecting known coefficients of higher-order splitting terms and reducing the effect of the variations. In conclusion, the formalism also allows for the enhancement of rare partonic splittings, such as g→bb¯ and q→qγ, to obtain weighted samples enriched in these splittings while preserving the correct physical Sudakov factors.« less

Gravitational effects from a series of IVS R&D VLBI-sessions with observations close to the Sun

NASA Astrophysics Data System (ADS)

Heinkelmann, R.; Soja, B.; Schuh, H.

2015-08-01

In 2011 and 2012 the IVS observed twelve VLBI research and development (R&D) sessions that include successful observations as angularly close as 3.9° from the heliocenter. Among others, one purpose of these IVS-R&D sessions was to achieve an improvement in the determination of the PPN parameter γ . Besides, by analyzing this specific set of IVS sessions, it was for the first time possible to measure the dispersive effect of the Solar corona with VLBI (Soja et al., 2014). In this work we assess the formal error of the γ-parameter and the contributions of the various terms to the partial derivative of the γ-parameter. Furthermore, we investigate the size of the gravitational delays caused by: (i) Solar monopole field at rest and with approximately linear translation, (ii) rotation of the Solar monopole field, (iii) Solar gravitational field quadrupole expansion, and (iv) Solar higher order term.

Maximum-entropy reconstruction method for moment-based solution of the Boltzmann equation

NASA Astrophysics Data System (ADS)

Summy, Dustin; Pullin, Dale

2013-11-01

We describe a method for a moment-based solution of the Boltzmann equation. This starts with moment equations for a 10 + 9 N , N = 0 , 1 , 2 . . . -moment representation. The partial-differential equations (PDEs) for these moments are unclosed, containing both higher-order moments and molecular-collision terms. These are evaluated using a maximum-entropy construction of the velocity distribution function f (c , x , t) , using the known moments, within a finite-box domain of single-particle-velocity (c) space. Use of a finite-domain alleviates known problems (Junk and Unterreiter, Continuum Mech. Thermodyn., 2002) concerning existence and uniqueness of the reconstruction. Unclosed moments are evaluated with quadrature while collision terms are calculated using a Monte-Carlo method. This allows integration of the moment PDEs in time. Illustrative examples will include zero-space- dimensional relaxation of f (c , t) from a Mott-Smith-like initial condition toward equilibrium and one-space dimensional, finite Knudsen number, planar Couette flow. Comparison with results using the direct-simulation Monte-Carlo method will be presented.

Mercury concentration in maternal serum, cord blood, and placenta in patients with amalgam dental fillings: effects on fetal biometric measurements.

PubMed

Bedir Findik, Rahime; Celik, Huseyin Tugrul; Ersoy, Ali Ozgur; Tasci, Yasemin; Moraloglu, Ozlem; Karakaya, Jale

2016-11-01

We aimed to determine the extent to which mercury is transmitted from the mother to fetus via the umbilical cord in patients with amalgam dental fillings, and its effect on fetal biometric measurements. Twenty-eight patients as the study group with amalgam fillings, and 32 of them as the control group were included in this prospective case-control study. The mercury levels were measured in the maternal and cord venous sera, and the placental samples. Two groups were compared in terms of these and the fetal/neonatal biometric measurements. In the study group, the maternal and umbilical cord mercury levels were found to be significantly higher than those from the control group (p = 0.006 and p = 0.010, respectively). These high levels did not affect the fetal biometric measurements. The presence of high serum mercury levels in pregnant women with amalgam fillings is important, and warrants further long-term studies in order to investigate the fetal neurological effects as well.

Comparing lagged linear correlation, lagged regression, Granger causality, and vector autoregression for uncovering associations in EHR data.

PubMed

Levine, Matthew E; Albers, David J; Hripcsak, George

2016-01-01

Time series analysis methods have been shown to reveal clinical and biological associations in data collected in the electronic health record. We wish to develop reliable high-throughput methods for identifying adverse drug effects that are easy to implement and produce readily interpretable results. To move toward this goal, we used univariate and multivariate lagged regression models to investigate associations between twenty pairs of drug orders and laboratory measurements. Multivariate lagged regression models exhibited higher sensitivity and specificity than univariate lagged regression in the 20 examples, and incorporating autoregressive terms for labs and drugs produced more robust signals in cases of known associations among the 20 example pairings. Moreover, including inpatient admission terms in the model attenuated the signals for some cases of unlikely associations, demonstrating how multivariate lagged regression models' explicit handling of context-based variables can provide a simple way to probe for health-care processes that confound analyses of EHR data.

FEL system with homogeneous average output

DOEpatents

Douglas, David R.; Legg, Robert; Whitney, R. Roy; Neil, George; Powers, Thomas Joseph

2018-01-16

A method of varying the output of a free electron laser (FEL) on very short time scales to produce a slightly broader, but smooth, time-averaged wavelength spectrum. The method includes injecting into an accelerator a sequence of bunch trains at phase offsets from crest. Accelerating the particles to full energy to result in distinct and independently controlled, by the choice of phase offset, phase-energy correlations or chirps on each bunch train. The earlier trains will be more strongly chirped, the later trains less chirped. For an energy recovered linac (ERL), the beam may be recirculated using a transport system with linear and nonlinear momentum compactions M.sub.56, which are selected to compress all three bunch trains at the FEL with higher order terms managed.

Non-linear non-local molecular electrodynamics with nano-optical fields.

PubMed

Chernyak, Vladimir Y; Saurabh, Prasoon; Mukamel, Shaul

2015-10-28

The interaction of optical fields sculpted on the nano-scale with matter may not be described by the dipole approximation since the fields may vary appreciably across the molecular length scale. Rather than incrementally adding higher multipoles, it is advantageous and more physically transparent to describe the optical process using non-local response functions that intrinsically include all multipoles. We present a semi-classical approach for calculating non-local response functions based on the minimal coupling Hamiltonian. The first, second, and third order response functions are expressed in terms of correlation functions of the charge and the current densities. This approach is based on the gauge invariant current rather than the polarization, and on the vector potential rather than the electric and magnetic fields.

Numerical analysis of wavefront aberration correction using multielectrode electrowetting-based devices.

PubMed

Zohrabi, Mo; Cormack, Robert H; Mccullough, Connor; Supekar, Omkar D; Gibson, Emily A; Bright, Victor M; Gopinath, Juliet T

2017-12-11

We present numerical simulations of multielectrode electrowetting devices used in a novel optical design to correct wavefront aberration. Our optical system consists of two multielectrode devices, preceded by a single fixed lens. The multielectrode elements function as adaptive optical devices that can be used to correct aberrations inherent in many imaging setups, biological samples, and the atmosphere. We are able to accurately simulate the liquid-liquid interface shape using computational fluid dynamics. Ray tracing analysis of these surfaces shows clear evidence of aberration correction. To demonstrate the strength of our design, we studied three different input aberrations mixtures that include astigmatism, coma, trefoil, and additional higher order aberration terms, with amplitudes as large as one wave at 633 nm.

Nanoscaled surface patterning of conducting polymers.

PubMed

Jiang, Lin; Wang, Xing; Chi, Lifeng

2011-05-23

In continuing the steady development of integrated-circuit-related fabrication, the ability to pattern conducting polymers into smaller and smaller sizes in order to realize devices with enhanced performance or even wholly new properties begins to take a more prominent role in their advanced applications. This review summarizes the recent advances in top-down and bottom-up patterning of conducting polymers on surfaces with different approaches including direct writing, in-situ synthesis or assembly, etching, and nanoscratching. All of the latest emerging strategies have the potential to go beyond the current state of the art towards real progress in terms of high-precision positioning, high resolution, high throughout, higher stability, facile processing, and lower-cost production. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

YORP on tumbling asteroids

NASA Astrophysics Data System (ADS)

Rozek, A.; Breiter, S.; Vokrouhlicky, D.

2011-10-01

A semi-analytical model of the Yarkovsky-O'Keefe- Radzievskii-Paddack (YORP) effect on an asteroid spin in non principal axis rotation state is presented. Assuming zero conductivity, the YORP torque is represented by spherical harmonics series with vector coefficients, allowing to use any degree and order of approximation. Within the quadrupole approximation of the illumination function we find the same first integrals involving rotational momentum, obliquity and dynamical inertia that were obtained by Cicaló and Scheeres [1]. The integrals do not exist when higher degree terms of illumination function are included and then the asymptotic states known from Vokrouhlický et al. [2] appear. This resolves an apparent contradiction between earlier results. Averaged equations of motion admit stable and unstable limit cycle solutions that were not detected previously.

Disentangling working memory processes during spatial span assessment: a modeling analysis of preferred eye movement strategies.

PubMed

Patt, Virginie M; Thomas, Michael L; Minassian, Arpi; Geyer, Mark A; Brown, Gregory G; Perry, William

2014-01-01

The neurocognitive processes involved during classic spatial working memory (SWM) assessment were investigated by examining naturally preferred eye movement strategies. Cognitively healthy adult volunteers were tested in a computerized version of the Corsi Block-Tapping Task--a spatial span task requiring the short term maintenance of a series of locations presented in a specific order--coupled with eye tracking. Modeling analysis was developed to characterize eye-tracking patterns across all task phases, including encoding, retention, and recall. Results revealed a natural preference for local gaze maintenance during both encoding and retention, with fewer than 40% fixated targets. These findings contrasted with the stimulus retracing pattern expected during recall as a result of task demands, with 80% fixated targets. Along with participants' self-reported strategies of mentally "making shapes," these results suggest the involvement of covert attention shifts and higher order cognitive Gestalt processes during spatial span tasks, challenging instrument validity as a single measure of SWM storage capacity.

7 CFR 1219.14 - Importer.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.14 Importer. Importer means any person who imports Hass avocados into the United States. The term includes a person who...

7 CFR 1219.14 - Importer.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.14 Importer. Importer means any person who imports Hass avocados into the United States. The term includes a person who...

7 CFR 1219.14 - Importer.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.14 Importer. Importer means any person who imports Hass avocados into the United States. The term includes a person who...

7 CFR 1219.14 - Importer.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.14 Importer. Importer means any person who imports Hass avocados into the United States. The term includes a person who...

Time accurate application of the MacCormack 2-4 scheme on massively parallel computers

NASA Technical Reports Server (NTRS)

Hudson, Dale A.; Long, Lyle N.

1995-01-01

Many recent computational efforts in turbulence and acoustics research have used higher order numerical algorithms. One popular method has been the explicit MacCormack 2-4 scheme. The MacCormack 2-4 scheme is second order accurate in time and fourth order accurate in space, and is stable for CFL's below 2/3. Current research has shown that the method can give accurate results but does exhibit significant Gibbs phenomena at sharp discontinuities. The impact of adding Jameson type second, third, and fourth order artificial viscosity was examined here. Category 2 problems, the nonlinear traveling wave and the Riemann problem, were computed using a CFL number of 0.25. This research has found that dispersion errors can be significantly reduced or nearly eliminated by using a combination of second and third order terms in the damping. Use of second and fourth order terms reduced the magnitude of dispersion errors but not as effectively as the second and third order combination. The program was coded using Thinking Machine's CM Fortran, a variant of Fortran 90/High Performance Fortran, and was executed on a 2K CM-200. Simple extrapolation boundary conditions were used for both problems.

Relativistic stars in degenerate higher-order scalar-tensor theories after GW170817

NASA Astrophysics Data System (ADS)

Kobayashi, Tsutomu; Hiramatsu, Takashi

2018-05-01

We study relativistic stars in degenerate higher-order scalar-tensor theories that evade the constraint on the speed of gravitational waves imposed by GW170817. It is shown that the exterior metric is given by the usual Schwarzschild solution if the lower order Horndeski terms are ignored in the Lagrangian and a shift symmetry is assumed. However, this class of theories exhibits partial breaking of Vainshtein screening in the stellar interior and thus modifies the structure of a star. Employing a simple concrete model, we show that for high-density stars the mass-radius relation is altered significantly even if the parameters are chosen so that only a tiny correction is expected in the Newtonian regime. We also find that, depending on the parameters, there is a maximum central density above which solutions cease to exist.

Probing baryogenesis through the Higgs boson self-coupling

NASA Astrophysics Data System (ADS)

Reichert, M.; Eichhorn, A.; Gies, H.; Pawlowski, J. M.; Plehn, T.; Scherer, M. M.

2018-04-01

The link between a modified Higgs self-coupling and the strong first-order phase transition necessary for baryogenesis is well explored for polynomial extensions of the Higgs potential. We broaden this argument beyond leading polynomial expansions of the Higgs potential to higher polynomial terms and to nonpolynomial Higgs potentials. For our quantitative analysis we resort to the functional renormalization group, which allows us to evolve the full Higgs potential to higher scales and finite temperature. In all cases we find that a strong first-order phase transition manifests itself in an enhancement of the Higgs self-coupling by at least 50%, implying that such modified Higgs potentials should be accessible at the LHC.

A Hierarchy of Transport Approximations for High Energy Heavy (HZE) Ions

NASA Technical Reports Server (NTRS)

Wilson, John W.; Lamkin, Stanley L.; Hamidullah, Farhat; Ganapol, Barry D.; Townsend, Lawrence W.

1989-01-01

The transport of high energy heavy (HZE) ions through bulk materials is studied neglecting energy dependence of the nuclear cross sections. A three term perturbation expansion appears to be adequate for most practical applications for which penetration depths are less than 30 g per sq cm of material. The differential energy flux is found for monoenergetic beams and for realistic ion beam spectral distributions. An approximate formalism is given to estimate higher-order terms.

Possibilities and limitations of rod-beam theories. [nonlinear distortion tensor and nonlinear stress tensors

NASA Technical Reports Server (NTRS)

Peterson, D.

1979-01-01

Rod-beam theories are founded on hypotheses such as Bernouilli's suggesting flat cross-sections under deformation. These assumptions, which make rod-beam theories possible, also limit the accuracy of their analysis. It is shown that from a certain order upward terms of geometrically nonlinear deformations contradict the rod-beam hypotheses. Consistent application of differential geometry calculus also reveals differences from existing rod theories of higher order. These differences are explained by simple examples.

Exploratory Movement Generates Higher-Order Information That Is Sufficient for Accurate Perception of Scaled Egocentric Distance

PubMed Central

Mantel, Bruno; Stoffregen, Thomas A.; Campbell, Alain; Bardy, Benoît G.

2015-01-01

Body movement influences the structure of multiple forms of ambient energy, including optics and gravito-inertial force. Some researchers have argued that egocentric distance is derived from inferential integration of visual and non-visual stimulation. We suggest that accurate information about egocentric distance exists in perceptual stimulation as higher-order patterns that extend across optics and inertia. We formalize a pattern that specifies the egocentric distance of a stationary object across higher-order relations between optics and inertia. This higher-order parameter is created by self-generated movement of the perceiver in inertial space relative to the illuminated environment. For this reason, we placed minimal restrictions on the exploratory movements of our participants. We asked whether humans can detect and use the information available in this higher-order pattern. Participants judged whether a virtual object was within reach. We manipulated relations between body movement and the ambient structure of optics and inertia. Judgments were precise and accurate when the higher-order optical-inertial parameter was available. When only optic flow was available, judgments were poor. Our results reveal that participants perceived egocentric distance from the higher-order, optical-inertial consequences of their own exploratory activity. Analysis of participants’ movement trajectories revealed that self-selected movements were complex, and tended to optimize availability of the optical-inertial pattern that specifies egocentric distance. We argue that accurate information about egocentric distance exists in higher-order patterns of ambient energy, that self-generated movement can generate these higher-order patterns, and that these patterns can be detected and used to support perception of egocentric distance that is precise and accurate. PMID:25856410

Guidelines and Recommendations on the Use of Higher Order Finite Elements for Bending Analysis of Plates

NASA Astrophysics Data System (ADS)

Carrera, E.; Miglioretti, F.; Petrolo, M.

2011-11-01

This paper compares and evaluates various plate finite elements to analyse the static response of thick and thin plates subjected to different loading and boundary conditions. Plate elements are based on different assumptions for the displacement distribution along the thickness direction. Classical (Kirchhoff and Reissner-Mindlin), refined (Reddy and Kant), and other higher-order displacement fields are implemented up to fourth-order expansion. The Unified Formulation UF by the first author is used to derive finite element matrices in terms of fundamental nuclei which consist of 3×3 arrays. The MITC4 shear-locking free type formulation is used for the FE approximation. Accuracy of a given plate element is established in terms of the error vs. thickness-to-length parameter. A significant number of finite elements for plates are implemented and compared using displacement and stress variables for various plate problems. Reduced models that are able to detect the 3D solution are built and a Best Plate Diagram (BPD) is introduced to give guidelines for the construction of plate theories based on a given accuracy and number of terms. It is concluded that the UF is a valuable tool to establish, for a given plate problem, the most accurate FE able to furnish results within a certain accuracy range. This allows us to obtain guidelines and recommendations in building refined elements in the bending analysis of plates for various geometries, loadings, and boundary conditions.

Testing higher-order Lagrangian perturbation theory against numerical simulations. 2: Hierarchical models

NASA Technical Reports Server (NTRS)

Melott, A. L.; Buchert, T.; Weib, A. G.

1995-01-01

We present results showing an improvement of the accuracy of perturbation theory as applied to cosmological structure formation for a useful range of scales. The Lagrangian theory of gravitational instability of Friedmann-Lemaitre cosmogonies is compared with numerical simulations. We study the dynamics of hierarchical models as a second step. In the first step we analyzed the performance of the Lagrangian schemes for pancake models, the difference being that in the latter models the initial power spectrum is truncated. This work probed the quasi-linear and weakly non-linear regimes. We here explore whether the results found for pancake models carry over to hierarchical models which are evolved deeply into the non-linear regime. We smooth the initial data by using a variety of filter types and filter scales in order to determine the optimal performance of the analytical models, as has been done for the 'Zel'dovich-approximation' - hereafter TZA - in previous work. We find that for spectra with negative power-index the second-order scheme performs considerably better than TZA in terms of statistics which probe the dynamics, and slightly better in terms of low-order statistics like the power-spectrum. However, in contrast to the results found for pancake models, where the higher-order schemes get worse than TZA at late non-linear stages and on small scales, we here find that the second-order model is as robust as TZA, retaining the improvement at later stages and on smaller scales. In view of these results we expect that the second-order truncated Lagrangian model is especially useful for the modelling of standard dark matter models such as Hot-, Cold-, and Mixed-Dark-Matter.

A {3,2}-Order Bending Theory for Laminated Composite and Sandwich Beams

NASA Technical Reports Server (NTRS)

Cook, Geoffrey M.; Tessler, Alexander

1998-01-01

A higher-order bending theory is derived for laminated composite and sandwich beams thus extending the recent {1,2}-order theory to include third-order axial effect without introducing additional kinematic variables. The present theory is of order {3,2} and includes both transverse shear and transverse normal deformations. A closed-form solution to the cylindrical bending problem is derived and compared with the corresponding exact elasticity solution. The numerical comparisons are focused on the most challenging material systems and beam aspect ratios which include moderate-to-thick unsymmetric composite and sandwich laminates. Advantages and limitations of the theory are discussed.

Population Heterogeneity in Mutation Rate Increases the Frequency of Higher-Order Mutants and Reduces Long-Term Mutational Load

PubMed Central

Alexander, Helen K.; Mayer, Stephanie I.; Bonhoeffer, Sebastian

2017-01-01

Abstract Mutation rate is a crucial evolutionary parameter that has typically been treated as a constant in population genetic analyses. However, the propensity to mutate is likely to vary among co-existing individuals within a population, due to genetic polymorphisms, heterogeneous environmental influences, and random physiological fluctuations. We review the evidence for mutation rate heterogeneity and explore its consequences by extending classic population genetic models to allow an arbitrary distribution of mutation rate among individuals, either with or without inheritance. With this general new framework, we rigorously establish the effects of heterogeneity at various evolutionary timescales. In a single generation, variation of mutation rate about the mean increases the probability of producing zero or many simultaneous mutations on a genome. Over multiple generations of mutation and selection, heterogeneity accelerates the appearance of both deleterious and beneficial multi-point mutants. At mutation-selection balance, higher-order mutant frequencies are likewise boosted, while lower-order mutants exhibit subtler effects; nonetheless, population mean fitness is always enhanced. We quantify the dependencies on moments of the mutation rate distribution and selection coefficients, and clarify the role of mutation rate inheritance. While typical methods of estimating mutation rate will recover only the population mean, analyses assuming mutation rate is fixed to this mean could underestimate the potential for multi-locus adaptation, including medically relevant evolution in pathogenic and cancerous populations. We discuss the potential to empirically parameterize mutation rate distributions, which have to date hardly been quantified. PMID:27836985

Short-term Internet search using makes people rely on search engines when facing unknown issues.

PubMed

Wang, Yifan; Wu, Lingdan; Luo, Liang; Zhang, Yifen; Dong, Guangheng

2017-01-01

The Internet search engines, which have powerful search/sort functions and ease of use features, have become an indispensable tool for many individuals. The current study is to test whether the short-term Internet search training can make people more dependent on it. Thirty-one subjects out of forty subjects completed the search training study which included a pre-test, a six-day's training of Internet search, and a post-test. During the pre- and post- tests, subjects were asked to search online the answers to 40 unusual questions, remember the answers and recall them in the scanner. Un-learned questions were randomly presented at the recalling stage in order to elicited search impulse. Comparing to the pre-test, subjects in the post-test reported higher impulse to use search engines to answer un-learned questions. Consistently, subjects showed higher brain activations in dorsolateral prefrontal cortex and anterior cingulate cortex in the post-test than in the pre-test. In addition, there were significant positive correlations self-reported search impulse and brain responses in the frontal areas. The results suggest that a simple six-day's Internet search training can make people dependent on the search tools when facing unknown issues. People are easily dependent on the Internet search engines.

Short-term Internet search using makes people rely on search engines when facing unknown issues

PubMed Central

Wang, Yifan; Wu, Lingdan; Luo, Liang; Zhang, Yifen

2017-01-01

The Internet search engines, which have powerful search/sort functions and ease of use features, have become an indispensable tool for many individuals. The current study is to test whether the short-term Internet search training can make people more dependent on it. Thirty-one subjects out of forty subjects completed the search training study which included a pre-test, a six-day’s training of Internet search, and a post-test. During the pre- and post- tests, subjects were asked to search online the answers to 40 unusual questions, remember the answers and recall them in the scanner. Un-learned questions were randomly presented at the recalling stage in order to elicited search impulse. Comparing to the pre-test, subjects in the post-test reported higher impulse to use search engines to answer un-learned questions. Consistently, subjects showed higher brain activations in dorsolateral prefrontal cortex and anterior cingulate cortex in the post-test than in the pre-test. In addition, there were significant positive correlations self-reported search impulse and brain responses in the frontal areas. The results suggest that a simple six-day’s Internet search training can make people dependent on the search tools when facing unknown issues. People are easily dependent on the Internet search engines. PMID:28441408

Masses from an inhomogeneous partial difference equation with higher-order isospin contributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masson, P.J.; Jaenecke, J.

In the present work, a mass equation obtained as the solution of an inhomogeneous partial difference equation is used to predict masses of unknown neutron-rich and proton-rich nuclei. The inhomogeneous source terms contain shell-dependent symmetry energy expressions (quadratic in isospin), and include, as well, an independently derived shell-model Coulomb energy equation which describes all known Coulomb displacement energies with a standarad deviation of sigma/sub c/ = 41 keV. Perturbations of higher order in isospin, previously recognized as a cause of systematic effects in long-range mass extrapolations, are also incorporated. The most general solutions of the inhomogeneous difference equation have beenmore » deduced from a chi/sup 2/-minimization procedure based on the recent atomic mass adjustment of Wapstra, Audi, and Hoekstra. Subjecting the solutions further to the condition of charge symmetry preserves the accuracy of Coulomb energies and allows mass predictions for nuclei with both Ngreater than or equal toZ and Z>N. The solutions correspond to a mass equation with 470 parameters. Using this equation, 4385 mass values have been calculated for nuclei with Agreater than or equal to16 (except N = Z = odd for A<40), with a standard deviation of sigma/sub m/ = 194 keV from the experimental masses. copyright 1988 Academic Press, Inc.« less

Glossary of CERCLA-related terms and acronyms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-10-01

This glossary contains CERCLA-related terms that are most often encountered in the US Department of Energy (DOE) Environmental Restoration and Emergency Preparedness activities. Detailed definitions are included for key terms. The definitions included in this glossary are taken from the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), as amended, related federal rulemakings (e.g., 40 CFR 300, National Oil and Hazardous Substances Pollution Contingency Plan), assorted guidance documents prepared by the US Environmental Protection Agency (EPA), and DOE Order 5400.4. The source of each term is noted after the term. Terms presented in this document reflect revised and new definitionsmore » published before June 1, 1991. 20 refs.« less

Higher Education Finance Manual 1975.

ERIC Educational Resources Information Center

Collier, Douglas J.; Mertins, Paul J.

The Higher Education Finance Manual (HEFM) is intended to serve as a guide to higher education planners and managers in their understanding and use of institutional finance data. It addresses higher education finance data from the layman's perspective. The document includes definitions of accounting terms and descriptions of generally accepted…

Tackling higher derivative ghosts with the Euclidean path integral

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fontanini, Michele; Department of Physics, Syracuse University, Syracuse, New York 13244; Trodden, Mark

2011-05-15

An alternative to the effective field theory approach to treat ghosts in higher derivative theories is to attempt to integrate them out via the Euclidean path integral formalism. It has been suggested that this method could provide a consistent framework within which we might tolerate the ghost degrees of freedom that plague, among other theories, the higher derivative gravity models that have been proposed to explain cosmic acceleration. We consider the extension of this idea to treating a class of terms with order six derivatives, and find that for a general term the Euclidean path integral approach works in themore » most trivial background, Minkowski. Moreover we see that even in de Sitter background, despite some difficulties, it is possible to define a probability distribution for tensorial perturbations of the metric.« less

77 FR 27425 - Floor-Standing, Metal-Top Ironing Tables and Certain Parts Thereof From the People's Republic of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-10

..., complete or incomplete, and certain parts thereof. For purposes of this order, the term ``unassembled... an included feature such as an iron rest or linen rack. The term ``complete'' ironing table means... without additional features, e.g., iron rest or linen rack. The term ``incomplete'' ironing table means...

Silicone Molding and Lifetime Testing of Peripheral Nerve Interfaces for Neuroprostheses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupte, Kimaya; Tolosa, Vanessa

Implantable peripheral nerve cuffs have a large application in neuroprostheses as they can be used to restore sensation to those with upper limb amputations. Modern day prosthetics, while lessening the pain associated with phantom limb syndrome, have limited fine motor control and do not provide sensory feedback to patients. Sensory feedback with prosthetics requires communication between the nervous system and limbs, and is still a challenge to accomplish with amputees. Establishing this communication between the peripheral nerves in the arm and artificial limbs is vital as prosthetics research aims to provide sensory feedback to amputees. Peripheral nerve cuffs restore sensationmore » by electrically stimulating certain parts of the nerve in order to create feeling in the hand. Cuff electrodes have an advantage over standard electrodes as they have high selective stimulation by bringing the electrical interface close to the neural tissue in order to selectively activate targeted regions of a peripheral nerve. In order to further improve the selective stimulation of these nerve cuffs, there is need for finer spatial resolution among electrodes. One method to achieve a higher spatial resolution is to increase the electrode density on the cuff itself. Microfabrication techniques can be used to achieve this higher electrode density. Using L-Edit, a layout editor, microfabricated peripheral nerve cuffs were designed with a higher electrode density than the current model. This increase in electrode density translates to an increase in spatial resolution by at least one order of magnitude. Microfabricated devices also have two separate components that are necessary to understand before implantation: lifetime of the device and assembly to prevent nerve damage. Silicone molding procedures were optimized so that devices do not damage nerves in vivo, and lifetime testing was performed on test microfabricated devices to determine their lifetime in vivo. Future work of this project would include fabricating some of the designed devices and seeing how they compare to the current cuffs in terms of their electrical performance, lifetime, shape, and mechanical properties.« less

Comparison of Ocular Monochromatic Higher-order Aberrations in Normal Refractive Surgery Candidates of Arab and South Asian Origin

PubMed Central

Prakash, Gaurav; Srivastava, Dhruv; Choudhuri, Sounak; Bacero, Ruthchel

2016-01-01

Purpose: To compare the ocular monochromatic higher-order aberration. (HOA) profile in normal refractive surgery candidates of Arab and South Asian origin. Methods: This cross-sectional, observational, comparative study was performed in the cornea department of a specialty hospital. Normal refractive surgery candidates with no ocular morbidity except refractive error were recruited. Refractive surgery candidates underwent a preoperative evaluation, including wavefront aberrometry with the iDesign aberrometer (AMO, Inc., Santa Ana, California, United States). The HOA from right eyes were analyzed for HOA signed, absolute, and polar Zernike coefficients. Results: Two hundred Arab participants (group 1) and 200 participants of South-Asian origin (group 2) comprised the study sample. The age and refractive status were comparable between groups. The mean of the HOA root mean square (RMS) was 0.36 ± 17 μ and 0.38 ± 18 μ for Arab and South-Asian eyes, respectively (P < 0.05, rank sum test [RST]). Of the 22 higher order signed Zernike modes, only Z3−3, Z3−1,31, Z4−4, Z4−2, Z40, Z44, and Z5−5 were significantly different from zero (one sample t-test, P < 0.002, with a Bonferroni correction of 0.05/22). All the signed and absolute Zernike terms were comparable between groups (RST, P > 0.002 [0.05/22]). The polar coefficients for coma, trefoil, spherical aberration, and tetrafoil were comparable between groups (P > 0.05, RST). Combined RMS values of third, fourth, fifth, and sixth order also were comparable between groups (P > 0.05, RST). Conclusions: Preoperative whole eye HOA were similar for refractive surgery candidates of Arab and South-Asian origin. The values were comparable to historical data for Caucasian eyes and were lower than Asian (Chinese) eyes. These findings may aid in refining refractive nomograms for wavefront ablations. PMID:26957850

Comparison of Ocular Monochromatic Higher-order Aberrations in Normal Refractive Surgery Candidates of Arab and South Asian Origin.

PubMed

Prakash, Gaurav; Srivastava, Dhruv; Choudhuri, Sounak; Bacero, Ruthchel

2016-01-01

To compare the ocular monochromatic higher-order aberration. (HOA) profile in normal refractive surgery candidates of Arab and South Asian origin. This cross-sectional, observational, comparative study was performed in the cornea department of a specialty hospital. Normal refractive surgery candidates with no ocular morbidity except refractive error were recruited. Refractive surgery candidates underwent a preoperative evaluation, including wavefront aberrometry with the iDesign aberrometer (AMO, Inc., Santa Ana, California, United States). The HOA from right eyes were analyzed for HOA signed, absolute, and polar Zernike coefficients. Two hundred Arab participants (group 1) and 200 participants of South-Asian origin (group 2) comprised the study sample. The age and refractive status were comparable between groups. The mean of the HOA root mean square (RMS) was 0.36 ± 17 μ and 0.38 ± 18 μ for Arab and South-Asian eyes, respectively (P < 0.05, rank sum test [RST]). Of the 22 higher order signed Zernike modes, only Z3 (-3), Z3 (-1),3 (1), Z4 (-4), Z4 (-2), Z4 (0), Z4 (4), and Z5 (-5) were significantly different from zero (one sample t-test, P < 0.002, with a Bonferroni correction of 0.05/22). All the signed and absolute Zernike terms were comparable between groups (RST, P > 0.002 [0.05/22]). The polar coefficients for coma, trefoil, spherical aberration, and tetrafoil were comparable between groups (P > 0.05, RST). Combined RMS values of third, fourth, fifth, and sixth order also were comparable between groups (P > 0.05, RST). Preoperative whole eye HOA were similar for refractive surgery candidates of Arab and South-Asian origin. The values were comparable to historical data for Caucasian eyes and were lower than Asian (Chinese) eyes. These findings may aid in refining refractive nomograms for wavefront ablations.

3 CFR 13570 - Executive Order 13570 of April 18, 2011. Prohibiting Certain Transactions With Respect to North...

Code of Federal Regulations, 2012 CFR

2012-01-01

... Certain Transactions With Respect to North Korea 13570 Order 13570 Presidential Documents Executive Orders... “North Korea” includes the territory of the Democratic People's Republic of Korea and the Government of North Korea; and (e) the term “Government of North Korea” means the Government of the Democratic People...

Decision-making in chronic ecstasy users: a systematic review.

PubMed

Betzler, Felix; Viohl, Leonard; Romanczuk-Seiferth, Nina

2017-01-01

Different cognitive impairments have been reported as a result of long-term MDMA/ecstasy use. Increased impulsivity and altered decision-making have been shown to be associated with the development and maintenance of addictive disorders pointing toward the necessity to understand a potential impairment of decision-making due to MDMA use. Thus, assessing the long-term effects of MDMA is crucial in order to evaluate its controversially discussed therapeutic use. The aim of this systematic review was to summarize the scientific literature on potential effects of chronic MDMA use on higher order decision-making processes in humans. Therefore, a systematic search for controlled trials relevant to the topic has been performed. Only studies using specific tasks on decision-making were included that involved subjects in the drug-free interval with drug-naïve, and/or polydrug control groups. A total of 12 studies could be identified that met the inclusion criteria, all of which were cross-sectional studies. The findings on decision-making disturbances in MDMA users were heterogeneous. Seven studies reported increased risky decisions, whereas five studies did not find MDMA-specific influences on decision-making. Increased impulsivity was observed both in MDMA groups and in (poly)drug control groups in almost all studies. Thus, the current state of research does not allow for the conclusion that long-term use of MDMA affects decision-making behavior in general. More detailed specifications as well as further investigations of the relevant processes are needed. Significant tendencies toward risky decision-making among long-term MDMA use have been observed, but need to be confirmed by studies using a longitudinal design. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Wavefront measurements of phase plates combining a point-diffraction interferometer and a Hartmann-Shack sensor.

PubMed

Bueno, Juan M; Acosta, Eva; Schwarz, Christina; Artal, Pablo

2010-01-20

A dual setup composed of a point diffraction interferometer (PDI) and a Hartmann-Shack (HS) wavefront sensor was built to compare the estimates of wavefront aberrations provided by the two different and complementary techniques when applied to different phase plates. Results show that under the same experimental and fitting conditions both techniques provide similar information concerning the wavefront aberration map. When taking into account all Zernike terms up to 6th order, the maximum difference in root-mean-square wavefront error was 0.08 microm, and this reduced up to 0.03 microm when excluding lower-order terms. The effects of the pupil size and the order of the Zernike expansion used to reconstruct the wavefront were evaluated. The combination of the two techniques can accurately measure complicated phase profiles, combining the robustness of the HS and the higher resolution and dynamic range of the PDI.

Finite-temperature phase transitions of third and higher order in gauge theories at large N

DOE PAGES

Nishimura, Hiromichi; Pisarski, Robert D.; Skokov, Vladimir V.

2018-02-15

We study phase transitions in SU(∞) gauge theories at nonzero temperature using matrix models. Our basic assumption is that the effective potential is dominated by double trace terms for the Polyakov loops. As a function of the various parameters, related to terms linear, quadratic, and quartic in the Polyakov loop, the phase diagram exhibits a universal structure. In a large region of this parameter space, there is a continuous phase transition whose order is larger than second. This is a generalization of the phase transition of Gross, Witten, and Wadia (GWW). Depending upon the detailed form of the matrix model,more » the eigenvalue density and the behavior of the specific heat near the transition differ drastically. Here, we speculate that in the pure gauge theory, that although the deconfining transition is thermodynamically of first order, it can be nevertheless conformally symmetric at infnite N.« less

Effect of horizontal pick and place locations on shoulder kinematics.

PubMed

Könemann, R; Bosch, T; Kingma, I; Van Dieën, J H; De Looze, M P

2015-01-01

In this study the effects of horizontal bin locations in an order picking workstation on upper arm elevation, trunk inclination and hand use were investigated. Eight subjects moved (self-paced) light or heavy products (0.2 and 3.0 kg) from a central product bin to an inner or outer order bin (at 60 or 150 cm) on the left or right side of the workstation, while movements were recorded. The outer compared to inner bin location resulted in more upper arm elevation and trunk inclination per work cycle, both in terms of number of peak values and in terms of time integrals of angles (which is a dose measure over time). Considering the peak values and time integrals per minute (instead of per work cycle), these effects are reduced, due to the higher cycle times for outer bins. Hand use (left, right or both) was not affected by order bin locations.

Finite-temperature phase transitions of third and higher order in gauge theories at large N

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishimura, Hiromichi; Pisarski, Robert D.; Skokov, Vladimir V.

We study phase transitions in SU(∞) gauge theories at nonzero temperature using matrix models. Our basic assumption is that the effective potential is dominated by double trace terms for the Polyakov loops. As a function of the various parameters, related to terms linear, quadratic, and quartic in the Polyakov loop, the phase diagram exhibits a universal structure. In a large region of this parameter space, there is a continuous phase transition whose order is larger than second. This is a generalization of the phase transition of Gross, Witten, and Wadia (GWW). Depending upon the detailed form of the matrix model,more » the eigenvalue density and the behavior of the specific heat near the transition differ drastically. Here, we speculate that in the pure gauge theory, that although the deconfining transition is thermodynamically of first order, it can be nevertheless conformally symmetric at infnite N.« less

Neurolinguistic and Psycholinguistic Research on Learning Modes of Older Language Learners: Classroom Implications.

ERIC Educational Resources Information Center

Homstad, Alice

1987-01-01

Review of neurolinguistic and psycholinguistic research regarding older (over 40 years of age) second language learners suggests classroom implications for dealing with this population's pronunciation problems and ways to capitalize on their superiority to younger students in terms of higher order linguistic processing. (CB)

Assessing Higher-Order Thinking Using a Networked Portfolio System with Peer Assessment

ERIC Educational Resources Information Center

Liu, Eric Zhi-Feng; Zhuo, Yi-Chin; Yuan, Shyan-Ming

2004-01-01

In the past, the quantitative evidences of portfolio assessment have been explored under online instruction. Liu, Lin, and Yuan provide a long-term measure of peer-self, peer-instructor and self-instructor correlation coefficients under networked innovative assessment procedures. Analytical results indicated that undergraduate students could…

Double hard scattering without double counting

NASA Astrophysics Data System (ADS)

Diehl, Markus; Gaunt, Jonathan R.; Schönwald, Kay

2017-06-01

Double parton scattering in proton-proton collisions includes kinematic regions in which two partons inside a proton originate from the perturbative splitting of a single parton. This leads to a double counting problem between single and double hard scattering. We present a solution to this problem, which allows for the definition of double parton distributions as operator matrix elements in a proton, and which can be used at higher orders in perturbation theory. We show how the evaluation of double hard scattering in this framework can provide a rough estimate for the size of the higher-order contributions to single hard scattering that are affected by double counting. In a numeric study, we identify situations in which these higher-order contributions must be explicitly calculated and included if one wants to attain an accuracy at which double hard scattering becomes relevant, and other situations where such contributions may be neglected.

Speeding up spin-component-scaled third-order pertubation theory with the chain of spheres approximation: the COSX-SCS-MP3 method

NASA Astrophysics Data System (ADS)

Izsák, Róbert; Neese, Frank

2013-07-01

The 'chain of spheres' approximation, developed earlier for the efficient evaluation of the self-consistent field exchange term, is introduced here into the evaluation of the external exchange term of higher order correlation methods. Its performance is studied in the specific case of the spin-component-scaled third-order Møller--Plesset perturbation (SCS-MP3) theory. The results indicate that the approximation performs excellently in terms of both computer time and achievable accuracy. Significant speedups over a conventional method are obtained for larger systems and basis sets. Owing to this development, SCS-MP3 calculations on molecules of the size of penicillin (42 atoms) with a polarised triple-zeta basis set can be performed in ∼3 hours using 16 cores of an Intel Xeon E7-8837 processor with a 2.67 GHz clock speed, which represents a speedup by a factor of 8-9 compared to the previously most efficient algorithm. Thus, the increased accuracy offered by SCS-MP3 can now be explored for at least medium-sized molecules.

Thermo-Elastic Analysis of Internally Cooled Structures Using a Higher Order Theory

NASA Technical Reports Server (NTRS)

Arnold, Steven M.; Bednarcyk, Brett A.; Aboudi, Jacob

2001-01-01

This paper presents the results of a study on the thermomechanical behavior of internally cooled silicon nitride structures. Silicon nitride is under consideration for elevated temperature aerospace engine applications. and techniques for lowering the operating temperature of structures composed of this material are under development. Lowering the operating temperature provides a large payoff in terms of fatigue life and may be accomplished through the use of thermal barrier coatings (TBC's) and the novel concept of included cooling channels. Herein, an in-depth study is performed on the behavior of a flame-impinged silicon nitride plate with a TBC and internal channels cooled by forced air. The analysis is performed using the higher order theory for functionally graded materials (HOTFGM), which has been developed through NASA Glenn Research Center funding over the past several years. HOTFGM was chosen over the traditional finite element approach as a prelude to an examination of functionally graded silicon nitride structures for which HOTFGM is ideally suited. To accommodate the analysis requirement% of the internally cooled plate problem, two crucial enhancements were made to the two-dimensional Cartesian-based version of HOTFGM. namely, incorporation of internal boundary capabilities and incorporation of convective boundary conditions. Results indicate the viability and large benefits of cooling the plate via forced air through cooling channels. Furthermore, cooling can positively impact the stress and displacement fields present in the plate, yielding an additional payoff in terms of fatigue life. Finally, a spin-off capability resulted from inclusion of internal boundaries within HOTFGM; the ability to simulate the thermo-elastic response of structures with curved surfaces. This new capability is demonstrated, and through comparison with an analytical solution, shown to be viable and accurate.

Joint Development of a Fourth Generation Single Crystal Superalloy

NASA Technical Reports Server (NTRS)

Walston, S.; Cetel, A.; MacKay, R.; OHara, K.; Duhl, D.; Dreshfield, R.

2004-01-01

A new, fourth generation, single crystal superalloy has been jointly developed by GE Aircraft Engines, Pratt & Whitney, and NASA. The focus of the effort was to develop a turbine airfoil alloy with long-term durability for use in the High Speed Civil Transport. In order to achieve adequate long-time strength improvements at moderate temperatures and retain good microstructural stability, it was necessary to make significant composition changes from 2nd and 3rd generation single crystal superalloys. These included lower chromium levels, higher cobalt and rhenium levels and the inclusion of a new alloying element, ruthenium. It was found that higher Co levels were beneficial to reducing both TCP precipitation and SRZ formation. Ruthenium caused the refractory elements to partition more strongly to the ' phase, which resulted in better overall alloy stability. The final alloy, EPM 102, had significant creep rupture and fatigue improvements over the baseline production alloys and had acceptable microstructural stability. The alloy is currently being engine tested and evaluated for advanced engine applications.

Effect of temperature on the complexation of NpO 2 + with benzoic acid: Spectrophotometric and calorimetric studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yanqiu; Zhang, Zhicheng; Liu, Guokui

The equilibrium constants of the 1:1 NpO2+/benzoate complex were determined by spectrophotometric titrations at variable temperatures (T = 283 to 343 K) and the ionic strength of 1.05 mol · kg-1. The enthalpy of complexation at T = 298 K was determined by microcalorimetric titrations. Similar to other monocarboxylates, benzoate forms a weak complex with NpO2+ and the complexation is strengthened as the temperature is increased. The complexation is endothermic and is entropy-driven. The enhancement of the complexation at elevated temperatures is primarily attributed to the increasingly larger entropy gain when the water molecules are released from the highly-ordered solvationmore » spheres of NpO2+ and benzoate to the bulk solvent where the degree of disorder is higher at higher temperatures. The spectroscopic features of the Np(V)/benzoate system, including the effect of temperature on the absorption bands, are discussed in terms of ligand field splitting and a thermal expansion mechanism.« less

A highly accurate ab initio potential energy surface for methane.

PubMed

Owens, Alec; Yurchenko, Sergei N; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

2016-09-14

A new nine-dimensional potential energy surface (PES) for methane has been generated using state-of-the-art ab initio theory. The PES is based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set limit and incorporates a range of higher-level additive energy corrections. These include core-valence electron correlation, higher-order coupled cluster terms beyond perturbative triples, scalar relativistic effects, and the diagonal Born-Oppenheimer correction. Sub-wavenumber accuracy is achieved for the majority of experimentally known vibrational energy levels with the four fundamentals of (12)CH4 reproduced with a root-mean-square error of 0.70 cm(-1). The computed ab initio equilibrium C-H bond length is in excellent agreement with previous values despite pure rotational energies displaying minor systematic errors as J (rotational excitation) increases. It is shown that these errors can be significantly reduced by adjusting the equilibrium geometry. The PES represents the most accurate ab initio surface to date and will serve as a good starting point for empirical refinement.

Feedbacks between subglacial dynamics and long-term glacial landscape evolution (Invited)

NASA Astrophysics Data System (ADS)

Brædstrup, C. F.; Egholm, D. L.; Ugelvig, S. V.; Christensen, A. D.; Andersen, J. L.

2011-12-01

Several well-known glacial landforms (such as U-shaped troughs and cirques) are associated with characteristic length scales, indicating that the viscosity of the ice and the stress gradients associated with ice flow exert first-order controls on their formation. The evolution of these glacial landforms has so far mostly been explored using phenomenological models that simply link the subglacial erosion rate to sliding or ice discharge. In order to improve our understanding of the causal links between the glacial landforms and the physics of the subglacial environment, we have performed computational experiments with a higher-order ice sheet model (Egholm et al., 2009) capable of simulating the long-term evolution of subglacial dynamics at a high spatial resolution. The orientation and magnitude of subglacial stress components depend not only on ice thickness and ice surface gradients, but also on the details of the bed topography and the regional variations in ice flow velocity. As glaciers erode their beds and modify the morphology of glaciated valleys, the subglacial dynamics therefore change with important implications for the sliding patterns and the continued erosion rates. We focus this presentation on feedbacks between the evolving bed topography and the subglacial erosion patterns. We have performed our experiments with different sliding and erosion laws, including highly non-linear rules representing coulomb-type slip at the bed (Schoof, 2010) and a quarrying model associated to the level of cavitation (Iverson, 2012). The highly non-linear computational experiments are made possible by new and very efficient GPU-accelerated multigrid algorithms. The computational experiments show that higher-order stress effects associated with local changes to the bed gradient provide important stabilizing effects for example in overdeepenings and near topographic steps. The experiments also show how a narrow and meandering pre-glacial valley represents a much more stable environment for a glacier than a glacially eroded valley where slip instabilities can readily propagate upstream. References: Egholm, D. L. et al. Modeling the flow of glaciers in steep terrains: The integrated second-order shallow ice approximation (iSOSIA). Journal of Geophysical Research, 116, F02012 (2011). Iverson, N. R. A theory of glacial quarrying for landscape evolution models. Geology, v. 40, no. 8, 679-682 (2012). Schoof, C. The effect of cavitation on glacier sliding. Proc. R. Soc. A , 461, 609-627 (2005).

Feedbacks between subglacial dynamics and long-term glacial landscape evolution (Invited)

NASA Astrophysics Data System (ADS)

Brædstrup, C. F.; Egholm, D. L.; Ugelvig, S. V.; Christensen, A. D.; Andersen, J. L.

2013-12-01

Several well-known glacial landforms (such as U-shaped troughs and cirques) are associated with characteristic length scales, indicating that the viscosity of the ice and the stress gradients associated with ice flow exert first-order controls on their formation. The evolution of these glacial landforms has so far mostly been explored using phenomenological models that simply link the subglacial erosion rate to sliding or ice discharge. In order to improve our understanding of the causal links between the glacial landforms and the physics of the subglacial environment, we have performed computational experiments with a higher-order ice sheet model (Egholm et al., 2009) capable of simulating the long-term evolution of subglacial dynamics at a high spatial resolution. The orientation and magnitude of subglacial stress components depend not only on ice thickness and ice surface gradients, but also on the details of the bed topography and the regional variations in ice flow velocity. As glaciers erode their beds and modify the morphology of glaciated valleys, the subglacial dynamics therefore change with important implications for the sliding patterns and the continued erosion rates. We focus this presentation on feedbacks between the evolving bed topography and the subglacial erosion patterns. We have performed our experiments with different sliding and erosion laws, including highly non-linear rules representing coulomb-type slip at the bed (Schoof, 2010) and a quarrying model associated to the level of cavitation (Iverson, 2012). The highly non-linear computational experiments are made possible by new and very efficient GPU-accelerated multigrid algorithms. The computational experiments show that higher-order stress effects associated with local changes to the bed gradient provide important stabilizing effects for example in overdeepenings and near topographic steps. The experiments also show how a narrow and meandering pre-glacial valley represents a much more stable environment for a glacier than a glacially eroded valley where slip instabilities can readily propagate upstream. References: Egholm, D. L. et al. Modeling the flow of glaciers in steep terrains: The integrated second-order shallow ice approximation (iSOSIA). Journal of Geophysical Research, 116, F02012 (2011). Iverson, N. R. A theory of glacial quarrying for landscape evolution models. Geology, v. 40, no. 8, 679-682 (2012). Schoof, C. The effect of cavitation on glacier sliding. Proc. R. Soc. A , 461, 609-627 (2005).

Buried mine detection using fractal geometry analysis to the LWIR successive line scan data image

NASA Astrophysics Data System (ADS)

Araki, Kan

2012-06-01

We have engaged in research on buried mine/IED detection by remote sensing method using LWIR camera. A IR image of a ground, containing buried objects can be assumed as a superimposed pattern including thermal scattering which may depend on the ground surface roughness, vegetation canopy, and effect of the sun light, and radiation due to various heat interaction caused by differences in specific heat, size, and buried depth of the objects and local temperature of their surrounding environment. In this cumbersome environment, we introduce fractal geometry for analyzing from an IR image. Clutter patterns due to these complex elements have oftentimes low ordered fractal dimension of Hausdorff Dimension. On the other hand, the target patterns have its tendency of obtaining higher ordered fractal dimension in terms of Information Dimension. Random Shuffle Surrogate method or Fourier Transform Surrogate method is used to evaluate fractional statistics by applying shuffle of time sequence data or phase of spectrum. Fractal interpolation to each line scan was also applied to improve the signal processing performance in order to evade zero division and enhance information of data. Some results of target extraction by using relationship between low and high ordered fractal dimension are to be presented.

Novel third-order Lovelock wormhole solutions

NASA Astrophysics Data System (ADS)

Mehdizadeh, Mohammad Reza; Lobo, Francisco S. N.

2016-06-01

In this work, we consider wormhole geometries in third-order Lovelock gravity and investigate the possibility that these solutions satisfy the energy conditions. In this framework, by applying a specific equation of state, we obtain exact wormhole solutions, and by imposing suitable values for the parameters of the theory, we find that these geometries satisfy the weak energy condition in the vicinity of the throat, due to the presence of higher-order curvature terms. Finally, we trace out a numerical analysis, by assuming a specific redshift function, and find asymptotically flat solutions that satisfy the weak energy condition throughout the spacetime.

Implications of the federal court order banning the terms "light" and "mild": what difference could it make?

PubMed

Anderson, Stacey J; Ling, Pamela M; Glantz, Stanton A

2007-08-01

Federal District Judge Gladys Kessler found that the major American tobacco companies violated the Racketeer Influenced and Corrupt Organizations Act, defrauding the public by deceptively marketing "light" cigarettes. Judge Kessler's ruling prohibits the defendant tobacco companies from implying health benefits through using misleading terms such as "light", "mild" or "low-tar", or through other indirect means. This ruling could be interpreted narrowly as simply prohibiting certain words, or could be interpreted broadly as prohibiting implying health benefits by any other means, including colour, numbers or images. It is important to include indirect communications, as tobacco companies easily circumvent narrow advertising bans. A narrow interpretation would be inconsistent with the court's comprehensive factual findings of fraudulent intent by the industry. A broad interpretation of the Order, including existing brands, line extensions and new tobacco products such as potential reduced exposure products that are marketed as "cigarettes", Judge Kessler's order could make a substantial contribution to protecting health.

Technology Use in Higher Education Instruction

ERIC Educational Resources Information Center

Elzarka, Sammy

2012-01-01

The significance of integrating technology use in higher education instruction is undeniable. The benefits include those related to access to instruction by underserved populations, adequately preparing students for future careers, capitalizing on best instructional practices, developing higher order thinking activities, and engaging students…

Antioxidative defence mechanisms against reactive oxygen species in bovine retained and not-retained placenta: activity of glutathione peroxidase, glutathione transferase, catalase and superoxide dismutase.

PubMed

Kankofer, M

2001-05-01

Glutathione peroxidase (GSH-Px), glutathione transferase (GSH-Tr), catalase (CAT) and superoxide dismutase (SOD)-the members of enzymatic antioxidative defence mechanisms against reactive oxygen species-may play an important role in proper or improper release of bovine fetal membranes. The aim of the following study was the determination of GSH-Px, GSH-Tr, CAT and SOD activity in order to define antioxidative status of bovine placenta during retention of fetal membranes (RFM) in cows. Placental samples were collected immediately after spontaneous parturition or during caesarean section before term and at term and divided into six groups as follows: A: caesarean section before term without RFM; B: caesarean section before term with RFM; C: caesarean section at term without RFM; D: caesarean section at term with RFM; E: spontaneous delivery at term without RFM; F: spontaneous delivery at term with RFM. The enzyme activities in placental homogenates were measured spectrophotometrically. GSH-Px activity was statistically significantly higher in fetal than in maternal placenta in all examined groups, increased towards parturition and was higher in caesarean section groups than spontaneous delivery groups. Statistically significantly higher activities were noticed in retained than not-retained placentae. GSH-Tr activity was significantly lower in fetal than in maternal placenta. In preterm groups, the activity was statistically significantly higher in retained than not retained placenta. In term groups, the opposite relationship was observed, higher values in caesarean section groups than spontaneous delivery were noticed. CAT activity was statistically significantly higher in fetal than in maternal part of placenta in all groups examined. The highest values in C and D groups and the differences between retained and not-retained placenta were observed. SOD exhibited the highest values in preterm placenta and alterations between retained and not-retained fetal membranes. In conclusion, the activities of GSH-Px, GSH-Tr, CAT and SOD are altered in cases of retained fetal membranes which may suggest the activation of antioxidative mechanisms caused by the imbalance between production and neutralization of reactive oxygen species. Copyright 2001 Harcourt Publishers Ltd.

Nonlinear estimation theory applied to orbit determination

NASA Technical Reports Server (NTRS)

Choe, C. Y.

1972-01-01

The development of an approximate nonlinear filter using the Martingale theory and appropriate smoothing properties is considered. Both the first order and the second order moments were estimated. The filter developed can be classified as a modified Gaussian second order filter. Its performance was evaluated in a simulated study of the problem of estimating the state of an interplanetary space vehicle during both a simulated Jupiter flyby and a simulated Jupiter orbiter mission. In addition to the modified Gaussian second order filter, the modified truncated second order filter was also evaluated in the simulated study. Results obtained with each of these filters were compared with numerical results obtained with the extended Kalman filter and the performance of each filter is determined by comparison with the actual estimation errors. The simulations were designed to determine the effects of the second order terms in the dynamic state relations, the observation state relations, and the Kalman gain compensation term. It is shown that the Kalman gain-compensated filter which includes only the Kalman gain compensation term is superior to all of the other filters.

Computation of NLO processes involving heavy quarks using Loop-Tree Duality

NASA Astrophysics Data System (ADS)

Driencourt-Mangin, Félix

2017-03-01

We present a new method to compute higher-order corrections to physical cross-sections, at Next-to-Leading Order and beyond. This method, based on the Loop Tree Duality, leads to locally integrable expressions in four dimensions. By introducing a physically motivated momentum mapping between the momenta involved in the real and the virtual contributions, infrared singularities naturally cancel at integrand level, without the need to introduce subtraction counter-terms. Ultraviolet singularities are dealt with by using dual representations of suitable counter-terms, with some subtleties regarding the self-energy contributions. As an example, we apply this method to compute the 1 → 2 decay rate in the context of a scalar toy model with massive particles.

Perturbative Out of Equilibrium Quantum Field Theory beyond the Gradient Approximation and Generalized Boltzmann Equation

NASA Astrophysics Data System (ADS)

Ozaki, H.

2004-01-01

Using the closed-time-path formalism, we construct perturbative frameworks, in terms of quasiparticle picture, for studying quasiuniform relativistic quantum field systems near equilibrium and non-equilibrium quasistationary systems. We employ the derivative expansion and take in up to the second-order term, i.e., one-order higher than the gradient approximation. After constructing self-energy resummed propagator, we formulated two kinds of mutually equivalent perturbative frameworks: The first one is formulated on the basis of the ``bare'' number density function, and the second one is formulated on the basis of ``physical'' number density function. In the course of construction of the second framework, the generalized Boltzmann equations directly come out, which describe the evolution of the system.

Tensor Galileons and gravity

NASA Astrophysics Data System (ADS)

Chatzistavrakidis, Athanasios; Khoo, Fech Scen; Roest, Diederik; Schupp, Peter

2017-03-01

The particular structure of Galileon interactions allows for higher-derivative terms while retaining second order field equations for scalar fields and Abelian p-forms. In this work we introduce an index-free formulation of these interactions in terms of two sets of Grassmannian variables. We employ this to construct Galileon interactions for mixed-symmetry tensor fields and coupled systems thereof. We argue that these tensors are the natural generalization of scalars with Galileon symmetry, similar to p-forms and scalars with a shift-symmetry. The simplest case corresponds to linearised gravity with Lovelock invariants, relating the Galileon symmetry to diffeomorphisms. Finally, we examine the coupling of a mixed-symmetry tensor to gravity, and demonstrate in an explicit example that the inclusion of appropriate counterterms retains second order field equations.

Near integrability of kink lattice with higher order interactions

NASA Astrophysics Data System (ADS)

Jiang, Yun-Guo; Liu, Jia-Zhen; He, Song

2017-11-01

We make use of Manton’s analytical method to investigate the force between kinks and anti-kinks at large distances in 1+1 dimensional field theory. The related potential has infinite order corrections of exponential pattern, and the coefficients for each order are determined. These coefficients can also be obtained by solving the equation of the fluctuations around the vacuum. At the lowest order, the kink lattice represents the Toda lattice. With higher order correction terms, the kink lattice can represent one kind of generic Toda lattice. With only two sites, the kink lattice is classically integrable. If the number of sites of the lattice is larger than two, the kink lattice is not integrable but is a near integrable system. We make use of Flaschka’s variables to study the Lax pair of the kink lattice. These Flaschka’s variables have interesting algebraic relations and non-integrability can be manifested. We also discuss the higher Hamiltonians for the deformed open Toda lattice, which has a similar result to the ordinary deformed Toda. Supported by Shandong Provincial Natural Science Foundation (ZR2014AQ007), National Natural Science Foundation of China (11403015, U1531105), S. He is supported by Max-Planck fellowship in Germany and National Natural Science Foundation of China (11305235)

7 CFR 981.13 - Handler.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.13 Handler. Handler means any person handling almonds during any crop year, except that such term shall not include either a grower who sells only almonds of his own production at...

7 CFR 915.10 - Handle.

Code of Federal Regulations, 2013 CFR

2013-01-01

... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE AVOCADOS GROWN IN SOUTH FLORIDA Order... avocados within the production area or between the production area and any point outside thereof: Provided, That such term shall not include: (a) The sale or delivery of avocados to a handler, registered as such...

7 CFR 915.10 - Handle.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE AVOCADOS GROWN IN SOUTH FLORIDA Order... avocados within the production area or between the production area and any point outside thereof: Provided, That such term shall not include: (a) The sale or delivery of avocados to a handler, registered as such...

Sleep inertia, sleep homeostatic, and circadian influences on higher-order cognitive functions

PubMed Central

Ronda, Joseph M.; Czeisler, Charles A.; Wright, Kenneth P.

2016-01-01

Summary Sleep inertia, sleep homeostatic, and circadian processes modulate cognition, including reaction time, memory, mood, and alertness. How these processes influence higher-order cognitive functions is not well known. Six participants completed a 73-daylong study that included two 14-daylong 28h forced desynchrony protocols, to examine separate and interacting influences of sleep inertia, sleep homeostasis, and circadian phase on higher-order cognitive functions of inhibitory control and selective visual attention. Cognitive performance for most measures was impaired immediately after scheduled awakening and improved over the first ~2-4h of wakefulness (sleep inertia); worsened thereafter until scheduled bedtime (sleep homeostasis); and was worst at ~60° and best at ~240° (circadian modulation, with worst and best phases corresponding to ~9AM and ~9PM respectively, in individuals with a habitual waketime of 7AM). The relative influences of sleep inertia, sleep homeostasis, and circadian phase depended on the specific higher-order cognitive function task examined. Inhibitory control appeared to be modulated most strongly by circadian phase, whereas selective visual attention for a spatial-configuration search task was modulated most strongly by sleep inertia. These findings demonstrate that some higher-order cognitive processes are differentially sensitive to different sleep-wake regulatory processes. Differential modulation of cognitive functions by different sleep-wake regulatory processes has important implications for understanding mechanisms contributing to performance impairments during adverse circadian phases, sleep deprivation, and/or upon awakening from sleep. PMID:25773686

Propagation and coherence properties of higher order partially coherent dark hollow beams in turbulence

NASA Astrophysics Data System (ADS)

Eyyuboğlu, Halil Tanyer

2008-02-01

We formulate and evaluate in terms of graphical outputs, source and receiver plane expressions, the complex degree of coherence, beam size variation and power in bucket performance for higher order partially coherent dark hollow beams propagating in turbulent atmosphere. Our formulation is able to cover square, rectangular, circular, elliptical geometries for dark hollow and flat-topped beams in one single expression. From the graphical outputs of the receiver plane, it is observed that higher order partially coherent dark hollow beams will initially develop an outer ring around a central lobe, but will eventually evolve towards a Gaussian shape as the propagation distance is extended. It is further observed that stronger turbulence levels and greater partial coherence have similar effects on beam profile. During propagation, modulus of complex degree of coherence of partially coherent dark hollow beams appears to rise above that of the source plane values, reaching as high as near unity. Beam size analysis shows that, among the types examined, (nearly) flat-topped beam experiences the least beam expansion. Power in bucket analysis indicates that lowest order square fully coherent dark beam offers the best power capturing.

Modulational instability and higher-order rogue waves with parameters modulation in a coupled integrable AB system via the generalized Darboux transformation.

PubMed

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.

Higher-order mode rf guns

NASA Astrophysics Data System (ADS)

Lewellen, John W.

2001-04-01

Traditional photocathode rf gun design is based around the use of TM0,1,0-mode cavities. This is typically done in the interest of obtaining the highest possible gradient per unit supplied rf power and for historical reasons. In a multicell, aperture-coupled photoinjector, however, the gun as a whole is produced from strongly coupled cavities oscillating in a π mode. This design requires very careful preparation and tuning, as the field balance and resonant frequencies are easily disturbed. Side-coupled designs are often avoided because of the dipole modes introduced into the cavity fields. This paper proposes the use of a single higher-order mode rf cavity in order to generate the desired on-axis fields. It is shown that the field experienced by a beam in a higher-order mode rf gun is initially very similar to traditional 1.5- or 2.5-cell π-mode gun fields, and projected performance in terms of beam quality is also comparable. The new design has the advantages of much greater ease of fabrication, immunity from coupled-cell effects, and simpler tuning procedures. Because of the gun geometry, the possibility also exists for improved temperature stabilization and cooling for high duty-cycle applications.

Superconducting order from disorder in 2H-TaSe 2-xS x

DOE PAGES

Li, Lijun; Deng, Xiaoyu; Wang, Zhen; ...

2017-02-24

Here, we report on the emergence of robust superconducting order in single crystal alloys of TaSe 2$ -$x S x (0 ≤ × ≤2). The critical temperature of the alloy is surprisingly higher than that of the two end compounds TaSe2 and TaS2. The evolution of superconducting critical temperature T c(x) correlates with the full width at half maximum of the Bragg peaks and with the linear term of the high-temperature resistivity. The conductivity of the crystals near the middle of the alloy series is higher or similar than that of either one of the end members 2H-TaSe 2 and/ormore » 2H-TaS 2. It is known that in these materials superconductivity is in close competition with charge density wave order. We interpret our experimental findings in a picture where disorder tilts this balance in favor of superconductivity by destroying the charge density wave order.« less

Physicochemical properties related to long-term phosphorus retention by drinking-water treatment residuals.

PubMed

Makris, Konstantinos C; Harris, Willie G; O'Connor, George A; Obreza, Thomas A; Elliott, Herschel A

2005-06-01

Drinking-water treatment residuals (WTRs) are nonhazardous materials that can be obtained free-of-charge from drinking-water treatment plants to reduce soluble phosphorus (P) concentrations in poorly P sorbing soils. Phosphorus sorption capacities of WTRs can vary 1-2 orders of magnitude, on the basis of short-term equilibration times (up to 7 d), but studies dealing with long-term (weeks to months) P retention by WTRs are lacking. Properties that most affect long-term P sorption capacities are pertinent to the efficacy of WTRs as amendments to stabilize P in soils. This research addressed the long-term (up to 80 d) P sorption/desorption characteristics and kinetics for seven WTRs, including the influence of specific surface area (SSA), porosity, and total C content on the overall magnitude of P sorption by seven WTRs. The data confirm a strong but variable affinity for P by WTRs. Aluminum-based WTRs tended to have higher P sorption capacity than Fe-based WTRs. Phosphorus sorption with time was biphasic in nature for most samples and best fit to a second-order rate model. The P sorption rate dependency was strongly correlated with a hysteretic P desorption, consistent with kinetic limitations on P desorption from micropores. Oxalate-extractable Al + Fe concentrations of the WTRs did not effectively explain long-term (80 d) P sorption capacities of the WTRs. Micropore (CO2-based) SSAs were greater than BET-N2 SSAs for most WTRs, except those with the lowest (<80 g kg(-1)) total C content. There was a significant negative linear correlation between the total C content and the CO2/N2 SSA ratio. The data suggest that C in WTRs increases microporosity, but reduces P sorption per unit pore volume or surface area. Hence, variability in C content confounds direct relations among SSA, porosity, and P sorption. Total C, N2-based SSA, and CO2-based SSAs explained 82% of the variability in the long-term P sorption capacities of the WTRs. Prediction of long-term P sorption capacities for different WTRs may be achieved by taking into account the three proposed variables.

Stable static structures in models with higher-order derivatives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bazeia, D., E-mail: bazeia@fisica.ufpb.br; Departamento de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB; Lobão, A.S.

2015-09-15

We investigate the presence of static solutions in generalized models described by a real scalar field in four-dimensional space–time. We study models in which the scalar field engenders higher-order derivatives and spontaneous symmetry breaking, inducing the presence of domain walls. Despite the presence of higher-order derivatives, the models keep to equations of motion second-order differential equations, so we focus on the presence of first-order equations that help us to obtain analytical solutions and investigate linear stability on general grounds. We then illustrate the general results with some specific examples, showing that the domain wall may become compact and that themore » zero mode may split. Moreover, if the model is further generalized to include k-field behavior, it may contribute to split the static structure itself.« less

Rogue Waves and Lump Solitons of the (3+1)-Dimensional Generalized B-type Kadomtsev-Petviashvili Equation for Water Waves

NASA Astrophysics Data System (ADS)

Sun, Yan; Tian, Bo; Liu, Lei; Chai, Han-Peng; Yuan, Yu-Qiang

2017-12-01

In this paper, the (3+1)-dimensional generalized B-type Kadomtsev-Petviashvili equation for water waves is investigated. Through the Hirota method and Kadomtsev-Petviashvili hierarchy reduction, we obtain the first-order, higher-order, multiple rogue waves and lump solitons based on the solutions in terms of the Gramian. The first-order rogue waves are the line rogue waves which arise from the constant background and then disappear into the constant background again, while the first-order lump solitons propagate stably. Interactions among several first-order rogue waves which are described by the multiple rogue waves are presented. Elastic interactions of several first-order lump solitons are also presented. We find that the higher-order rogue waves and lump solitons can be treated as the superpositions of several first-order ones, while the interaction between the second-order lump solitons is inelastic. Supported by the National Natural Science Foundation of China under Grant Nos. 11772017, 11272023, and 11471050, by the Open Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications), China (IPOC: 2017ZZ05), and by the Fundamental Research Funds for the Central Universities of China under Grant No. 2011BUPTYB02

Relativistic effects on the bonding and properties of the hydrides of platinum

NASA Technical Reports Server (NTRS)

Dyall, Kenneth G.

1993-01-01

The ground state of PtH2 and several low-lying states of PtH(+) and PtH have been studied at the all-electron self-consistent-field level of theory to examine the importance of relativistic effects. The results of calculations based on Dirac-Hartree-Fock theory, nonrelativistic theory, and the spin-free no-pair relativistic approximation of Hess are compared to separate the effects of the spin-free terms and the spin-orbit terms of the Hamiltonian on the relativistic corrections to the molecular properties. Comparison is also made between first-order perturbation theory including the one-electron spin-free terms and the method of Hess to determine the size of effects beyond first order. It is found that the spin-orbit interaction significantly affects the properties and energetics of these molecules because of the participation of the Pt 5d orbitals in the bonding, and that effects beyond first order in perturbation theory are large. Any treatment of Pt compounds will have to include both the spin-free and spin-orbit interactions for an accurate description.

Calculation of Protein Heat Capacity from Replica-Exchange Molecular Dynamics Simulations with Different Implicit Solvent Models

DTIC Science & Technology

2008-10-30

rigorous Poisson-based methods generally apply a Lee-Richards mo- lecular surface.9 This surface is considered the de facto description for continuum...definition and calculation of the Born radii. To evaluate the Born radii, two approximations are invoked. The first is the Coulomb field approximation (CFA...energy term, and depending on the particular GB formulation, higher-order non- Coulomb correction terms may be added to the Born radii to account for the

Intrinsic differences in atomic ordering of calcium (alumino)silicate hydrates in conventional and alkali-activated cements

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, Claire E., E-mail: whitece@princeton.edu; Andlinger Center for Energy and the Environment, Princeton University, Princeton; Lujan Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos

2015-01-15

The atomic structures of calcium silicate hydrate (C–S–H) and calcium (–sodium) aluminosilicate hydrate (C–(N)–A–S–H) gels, and their presence in conventional and blended cement systems, have been the topic of significant debate over recent decades. Previous investigations have revealed that synthetic C–S–H gel is nanocrystalline and due to the chemical similarities between ordinary Portland cement (OPC)-based systems and low-CO{sub 2} alkali-activated slags, researchers have inferred that the atomic ordering in alkali-activated slag is the same as in OPC–slag cements. Here, X-ray total scattering is used to determine the local bonding environment and nanostructure of C(–A)–S–H gels present in hydrated tricalcium silicatemore » (C{sub 3}S), blended C{sub 3}S–slag and alkali-activated slag, revealing the large intrinsic differences in the extent of nanoscale ordering between C–S–H derived from C{sub 3}S and alkali-activated slag systems, which may have a significant influence on thermodynamic stability, and material properties at higher length scales, including long term durability of alkali-activated cements.« less

Quasilinear diffusion operator for wave-particle interactions in inhomogeneous magnetic fields

NASA Astrophysics Data System (ADS)

Catto, P. J.; Lee, J.; Ram, A. K.

2017-10-01

The Kennel-Engelmann quasilinear diffusion operator for wave-particle interactions is for plasmas in a uniform magnetic field. The operator is not suitable for fusion devices with inhomogeneous magnetic fields. Using drift kinetic and high frequency gyrokinetic equations for the particle distribution function, we have derived a quasilinear operator which includes magnetic drifts. The operator applies to RF waves in any frequency range and is particularly relevant for minority ion heating. In order to obtain a physically meaningful operator, the first order correction to the particle's magnetic moment has to be retained. Consequently, the gyrokinetic change of variables has to be retained to a higher order than usual. We then determine the perturbed distribution function from the gyrokinetic equation using a novel technique that solves the kinetic equation explicitly for certain parts of the function. The final form of the diffusion operator is compact and completely expressed in terms of the drift kinetic variables. It is not transit averaged and retains the full poloidal angle variation without any Fourier decomposition. The quasilinear diffusion operator reduces to the Kennel-Engelmann operator for uniform magnetic fields. Supported by DoE Grant DE-FG02-91ER-54109.

High-Order Polynomial Expansions (HOPE) for flux-vector splitting

NASA Technical Reports Server (NTRS)

Liou, Meng-Sing; Steffen, Chris J., Jr.

1991-01-01

The Van Leer flux splitting is known to produce excessive numerical dissipation for Navier-Stokes calculations. Researchers attempt to remedy this deficiency by introducing a higher order polynomial expansion (HOPE) for the mass flux. In addition to Van Leer's splitting, a term is introduced so that the mass diffusion error vanishes at M = 0. Several splittings for pressure are proposed and examined. The effectiveness of the HOPE scheme is illustrated for 1-D hypersonic conical viscous flow and 2-D supersonic shock-wave boundary layer interactions.

Evidence for modality-independent order coding in working memory.

PubMed

Depoorter, Ann; Vandierendonck, André

2009-03-01

The aim of the present study was to investigate the representation of serial order in working memory, more specifically whether serial order is coded by means of a modality-dependent or a modality-independent order code. This was investigated by means of a series of four experiments based on a dual-task methodology in which one short-term memory task was embedded between the presentation and recall of another short-term memory task. Two aspects were varied in these memory tasks--namely, the modality of the stimulus materials (verbal or visuo-spatial) and the presence of an order component in the task (an order or an item memory task). The results of this study showed impaired primary-task recognition performance when both the primary and the embedded task included an order component, irrespective of the modality of the stimulus materials. If one or both of the tasks did not contain an order component, less interference was found. The results of this study support the existence of a modality-independent order code.

A lattice Boltzmann model for the Burgers-Fisher equation.

PubMed

Zhang, Jianying; Yan, Guangwu

2010-06-01

A lattice Boltzmann model is developed for the one- and two-dimensional Burgers-Fisher equation based on the method of the higher-order moment of equilibrium distribution functions and a series of partial differential equations in different time scales. In order to obtain the two-dimensional Burgers-Fisher equation, vector sigma(j) has been used. And in order to overcome the drawbacks of "error rebound," a new assumption of additional distribution is presented, where two additional terms, in first order and second order separately, are used. Comparisons with the results obtained by other methods reveal that the numerical solutions obtained by the proposed method converge to exact solutions. The model under new assumption gives better results than that with second order assumption. (c) 2010 American Institute of Physics.

Gravity model improvement using GEOS-3 (GEM 9 and 10)

NASA Technical Reports Server (NTRS)

Lerch, F. J.; Klosko, S. M.; Laubscher, R. E.; Wagner, C. A.

1977-01-01

The use of collocation permitted GEM 9 to be a larger field than previous derived satellite models, GEM 9 having harmonics complete to 20 x 20 with selected higher degree terms. The satellite data set has approximately 840,000 observations, of which 200,000 are laser ranges taken on 9 satellites equipped with retroreflectors. GEM 10 is complete to 22 x 22 with selected higher degree terms out to degree and order 30 amounting to a total of 592 coefficients. Comparisons with surface gravity and altimeter data indicate a substantial improvement in GEM 9 over previous satellite solutions; GEM 9 is in even closer agreement with surface data than the previously published GEM 6 solution which contained surface gravity. In particular the free air gravity anomalies calculated from GEM 9 and a surface gravity solution are in excellent agreement for the high degree terms.

Alignment of learning objectives and assessments in therapeutics courses to foster higher-order thinking.

PubMed

FitzPatrick, Beverly; Hawboldt, John; Doyle, Daniel; Genge, Terri

2015-02-17

To determine whether national educational outcomes, course objectives, and classroom assessments for 2 therapeutics courses were aligned for curricular content and cognitive processes, and if they included higher-order thinking. Document analysis and student focus groups were used. Outcomes, objectives, and assessment tasks were matched for specific therapeutics content and cognitive processes. Anderson and Krathwohl's Taxonomy was used to define higher-order thinking. Students discussed whether assessments tested objectives and described their thinking when responding to assessments. There were 7 outcomes, 31 objectives, and 412 assessment tasks. The alignment for content and cognitive processes was not satisfactory. Twelve students participated in the focus groups. Students thought more short-answer questions than multiple choice questions matched the objectives for content and required higher-order thinking. The alignment analysis provided data that could be used to reveal and strengthen the enacted curriculum and improve student learning.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, Brian M.; Larson, Vincent E.

Microphysical processes, such as the formation, growth, and evaporation of precipitation, interact with variability and covariances (e.g., fluxes) in moisture and heat content. For instance, evaporation of rain may produce cold pools, which in turn may trigger fresh convection and precipitation. These effects are usually omitted or else crudely parameterized at subgrid scales in weather and climate models.A more formal approach is pursued here, based on predictive, horizontally averaged equations for the variances, covariances, and fluxes of moisture and heat content. These higher-order moment equations contain microphysical source terms. The microphysics terms can be integrated analytically, given a suitably simplemore » warm-rain microphysics scheme and an approximate assumption about the multivariate distribution of cloud-related and precipitation-related variables. Performing the integrations provides exact expressions within an idealized context.A large-eddy simulation (LES) of a shallow precipitating cumulus case is performed here, and it indicates that the microphysical effects on (co)variances and fluxes can be large. In some budgets and altitude ranges, they are dominant terms. The analytic expressions for the integrals are implemented in a single-column, higher-order closure model. Interactive single-column simulations agree qualitatively with the LES. The analytic integrations form a parameterization of microphysical effects in their own right, and they also serve as benchmark solutions that can be compared to non-analytic integration methods.« less

The case of value-based healthcare for people living with complex long-term conditions.

PubMed

Elf, Marie; Flink, Maria; Nilsson, Marie; Tistad, Malin; von Koch, Lena; Ytterberg, Charlotte

2017-01-11

There is a trend towards value-based health service, striving to cut costs while generating value for the patient. The overall objective comprises higher-quality health services and improved patient safety and cost efficiency. The approach could align with patient-centred care, as it entails a focus on the patient's experience of her or his entire cycle of care, including the use of well-defined outcome measurements. Challenges arise when the approach is applied to health services for people living with long-term complex conditions that require support from various healthcare services. The aim of this work is to critically discuss the value-based approach and its implications for patients with long-term complex conditions. Two cases from clinical practice and research form the foundation for our reasoning, illustrating several challenges regarding value-based health services for people living with long-term complex conditions. Achieving value-based health services that provide the health outcomes that matter to patients and providing greater patient-centredness will place increased demands on the healthcare system. Patients and their informal caregivers must be included in the development and establishment of outcome measures. The outcome measures must be standardized to allow evaluation of specific conditions at an aggregated level, but they must also be sensitive enough to capture each patient's individual needs and goals. Healthcare systems that strive to establish value-based services must collaborate beyond the organizational boundaries to create clear patient trajectories in order to avoid fragmentation. The shift towards value-based health services has the potential to align healthcare-service delivery with patient-centred care if serious efforts to take the patient's perspective into account are made. This is especially challenging in fragmented healthcare systems and for patients with long-term- and multi-setting-care needs.

Polymer quantization, stability and higher-order time derivative terms

NASA Astrophysics Data System (ADS)

Cumsille, Patricio; Reyes, Carlos M.; Ossandon, Sebastian; Reyes, Camilo

2016-03-01

The possibility that fundamental discreteness implicit in a quantum gravity theory may act as a natural regulator for ultraviolet singularities arising in quantum field theory has been intensively studied. Here, along the same expectations, we investigate whether a nonstandard representation called polymer representation can smooth away the large amount of negative energy that afflicts the Hamiltonians of higher-order time derivative theories, rendering the theory unstable when interactions come into play. We focus on the fourth-order Pais-Uhlenbeck model which can be reexpressed as the sum of two decoupled harmonic oscillators one producing positive energy and the other negative energy. As expected, the Schrödinger quantization of such model leads to the stability problem or to negative norm states called ghosts. Within the framework of polymer quantization we show the existence of new regions where the Hamiltonian can be defined well bounded from below.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Lijun; Deng, Xiaoyu; Wang, Zhen

Here, we report on the emergence of robust superconducting order in single crystal alloys of TaSe 2$ -$x S x (0 ≤ × ≤2). The critical temperature of the alloy is surprisingly higher than that of the two end compounds TaSe2 and TaS2. The evolution of superconducting critical temperature T c(x) correlates with the full width at half maximum of the Bragg peaks and with the linear term of the high-temperature resistivity. The conductivity of the crystals near the middle of the alloy series is higher or similar than that of either one of the end members 2H-TaSe 2 and/ormore » 2H-TaS 2. It is known that in these materials superconductivity is in close competition with charge density wave order. We interpret our experimental findings in a picture where disorder tilts this balance in favor of superconductivity by destroying the charge density wave order.« less

Higher Order Bases in a 2D Hybrid BEM/FEM Formulation

NASA Technical Reports Server (NTRS)

Fink, Patrick W.; Wilton, Donald R.

2002-01-01

The advantages of using higher order, interpolatory basis functions are examined in the analysis of transverse electric (TE) plane wave scattering by homogeneous, dielectric cylinders. A boundary-element/finite-element (BEM/FEM) hybrid formulation is employed in which the interior dielectric region is modeled with the vector Helmholtz equation, and a radiation boundary condition is supplied by an Electric Field Integral Equation (EFIE). An efficient method of handling the singular self-term arising in the EFIE is presented. The iterative solution of the partially dense system of equations is obtained using the Quasi-Minimal Residual (QMR) algorithm with an Incomplete LU Threshold (ILUT) preconditioner. Numerical results are shown for the case of an incident wave impinging upon a square dielectric cylinder. The convergence of the solution is shown versus the number of unknowns as a function of the completeness order of the basis functions.

Pushing Critical Thinking Skills With Multiple-Choice Questions: Does Bloom's Taxonomy Work?

PubMed

Zaidi, Nikki L Bibler; Grob, Karri L; Monrad, Seetha M; Kurtz, Joshua B; Tai, Andrew; Ahmed, Asra Z; Gruppen, Larry D; Santen, Sally A

2018-06-01

Medical school assessments should foster the development of higher-order thinking skills to support clinical reasoning and a solid foundation of knowledge. Multiple-choice questions (MCQs) are commonly used to assess student learning, and well-written MCQs can support learner engagement in higher levels of cognitive reasoning such as application or synthesis of knowledge. Bloom's taxonomy has been used to identify MCQs that assess students' critical thinking skills, with evidence suggesting that higher-order MCQs support a deeper conceptual understanding of scientific process skills. Similarly, clinical practice also requires learners to develop higher-order thinking skills that include all of Bloom's levels. Faculty question writers and examinees may approach the same material differently based on varying levels of knowledge and expertise, and these differences can influence the cognitive levels being measured by MCQs. Consequently, faculty question writers may perceive that certain MCQs require higher-order thinking skills to process the question, whereas examinees may only need to employ lower-order thinking skills to render a correct response. Likewise, seemingly lower-order questions may actually require higher-order thinking skills to respond correctly. In this Perspective, the authors describe some of the cognitive processes examinees use to respond to MCQs. The authors propose that various factors affect both the question writer and examinee's interaction with test material and subsequent cognitive processes necessary to answer a question.

7 CFR 981.51 - Requirements for reserve.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order... obligation with such almonds specified in the terms of the agency agreement authorized in § 981.67, including... receive credit by similarly delivering almonds to the Board or its designees. These requirements may be...

Sources of suspended sediment in the Waikele watershed, Oʻahu, Hawaiʻi

USGS Publications Warehouse

Izuka, Scot K.

2012-01-01

Data from streamflow/sediment gages and measurements of changes in channel-bed sediment storage were gathered between October 1, 2007, and September 30, 2010, to assess the sources of suspended sediment in the Waikele watershed, Oʻahu, Hawaiʻi. Streamflow from the watershed averaged 33 cubic feet per second during the study period, with interannual variations corresponding with variations in the frequency and magnitude of storm-flow peaks. Average streamflow during the study period was lower than the long-term average, but the study period included a storm on December 11, 2008, that caused record-high streamflows in parts of the watershed. Suspended-sediment yield from the Waikele watershed during the study period averaged 82,500 tons per year, which is 2.7 times higher than the long-term average. More than 90 percent of the yield during the study period was discharged during the December 11, 2008, storm. The study-period results are consistent with long-term records that show that the vast majority of suspended-sediment transport occurs during a few large storms. Results of this study also show that all but a small percentage of the suspended-sediment yield came from hillslopes. Only a small fraction of bed sediments is fine enough to be transported as suspended load; most bed sediments in the watershed are coarse. Silt and clay constitute less than 3 percent of the bed-sediment volume on average. Some larger clasts, however, can disintegrate during transport and contribute to the suspended load downstream. During the study period, suspended-sediment yield from the urbanized Mililani subbasin averaged 25 tons per year per square mile (tons/yr/mi2), which was much smaller than the yield from any other subbasin; these results indicate that urban land use yields much less sediment than other land uses. The wet, forested Kipapa subbasin had an average normalized hillslope suspended-sediment yield of 386 tons/yr/mi2; the average yield for forested areas in the watershed may be lower. Suspended-sediment yield from agricultural land use in the watershed is estimated to range between 5,590 and 6,440 tons/yr/mi2 during the study period; the long-term average is estimated to be 2,070 to 2,390 tons/yr/mi2. Of the three land uses considered, agriculture had by far the highest normalized suspended-sediment yield during this study - about an order of magnitude higher than forests and two orders of magnitude higher than urban areas.

Combined temperature and density series for fluid-phase properties. I. Square-well spheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, J. Richard; Schultz, Andrew J.; Kofke, David A.

Cluster integrals are evaluated for the coefficients of the combined temperature- and density-expansion of pressure: Z = 1 + B{sub 2}(β) η + B{sub 3}(β) η{sup 2} + B{sub 4}(β) η{sup 3} + ⋯, where Z is the compressibility factor, η is the packing fraction, and the B{sub i}(β) coefficients are expanded as a power series in reciprocal temperature, β, about β = 0. The methodology is demonstrated for square-well spheres with λ = [1.2-2.0], where λ is the well diameter relative to the hard core. For this model, the B{sub i} coefficients can be expressed in closed form asmore » a function of β, and we develop appropriate expressions for i = 2-6; these expressions facilitate derivation of the coefficients of the β series. Expanding the B{sub i} coefficients in β provides a correspondence between the power series in density (typically called the virial series) and the power series in β (typically called thermodynamic perturbation theory, TPT). The coefficients of the β series result in expressions for the Helmholtz energy that can be compared to recent computations of TPT coefficients to fourth order in β. These comparisons show good agreement at first order in β, suggesting that the virial series converges for this term. Discrepancies for higher-order terms suggest that convergence of the density series depends on the order in β. With selection of an appropriate approximant, the treatment of Helmholtz energy that is second order in β appears to be stable and convergent at least to the critical density, but higher-order coefficients are needed to determine how far this behavior extends into the liquid.« less

The short-term impacts of Earned Income Tax Credit disbursement on health.

PubMed

Rehkopf, David H; Strully, Kate W; Dow, William H

2014-12-01

There are conflicting findings regarding long- and short-term effects of income on health. Whereas higher average income is associated with better health, there is evidence that health behaviours worsen in the short-term following income receipt.Prior studies revealing such negative short-term effects of income receipt focus on specific subpopulations and examine a limited set of health outcomes. The United States Earned Income Tax Credit (EITC) is an income supplement tied to work, and is the largest poverty reduction programme in the USA. We utilize the fact that EITC recipients typically receive large cash transfers in the months of February,March and April, in order to examine associated changes in health outcomes that can fluctuate on a monthly basis. We examine associations with 30 outcomes in the categories of diet, food security, health behaviours, cardiovascular biomarkers, metabolic biomarkers and infection and immunity among 6925 individuals from the U.S. National Health and Nutrition Survey. Our research design approximates a natural experiment,since whether individuals were sampled during treatment or non-treatment months is independent of social, demographic and health characteristics that do not vary with time. There are both beneficial and detrimental short-term impacts of income receipt.Although there are detrimental impacts on metabolic factors among women, most other impacts are beneficial, including those for food security, smoking and trying to lose weight. The short-term impacts of EITC income receipt are not universally health promoting, but on balance there are more health benefits than detriments.

Trends in Childbirth before 39 Weeks’ Gestation without Medical Indication

PubMed Central

Kozhimannil, Katy B.; Macheras, Michelle; Lorch, Scott A.

2014-01-01

Background There is increasing attention to labor induction and cesarean delivery occurring at 37 0/7 – 38 6/7 weeks’ gestation (early-term) without medical indication. Objective To measure prevalence, change over time, patient characteristics, and infant outcomes associated with early-term nonindicated births. Research Design and Subjects Retrospective analysis using linked hospital discharge and birth certificate data for the 7,296,363 uncomplicated term (>37 0/7 weeks’ gestation) births between 1995-2009 in 3 states. Measures Early-term nonindicated birth is calculated using diagnosis codes and birth certificate records. Secondary outcomes included infant prolonged length of stay and respiratory distress. Results Across uncomplicated term births, the early-term nonindicated birth rate was 3.18%. After adjustment, the risk of nonindicated birth before 39 weeks was 86% higher in 2009 than 1995 (hazard ratio [HR]=1.86 [95% confidence interval (CI), 1.81–1.90]), peaking in 2006 (HR=2.03; P < .001). Factors independently associated with higher odds included maternal age, higher education levels, private health insurance, and delivering at smaller-volume or nonteaching hospitals. Black women had higher risk of nonindicated cesarean birth (HR=1.29 [95% CI, 1.27–1.32]), which was associated with greater odds of prolonged length of stay (adjusted odds ratio [AOR]=1.60 [95% CI, 1.57–1.64]) and infant respiratory distress (AOR= 2.44 [95% CI, 2.37–2.50]) compared with births after 38 6/7 weeks. Early-term nonindicated induction was also associated with comparatively greater odds of prolonged length of stay (AOR=1.20 [95% CI, 1.17–1.23]). Conclusion Nearly 4% of all uncomplicated births to term infants occurred before 39 0/7 weeks' gestation without medical indication. These births were associated with adverse infant outcomes. PMID:24926713