Nuclear energy density functional from chiral pion-nucleon dynamics revisited
Kaiser, N.; Weise, W.
2010-05-01
We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from 1 π-exchange, iterated 1 π-exchange, and irreducible 2 π-exchange with intermediate Δ-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass M(ρ) entering the energy density functional is identical to the one of Fermi-liquid theory when employing the improved density-matrix expansion. The strength F(ρ) of the ( surface-term as provided by the pion-exchange dynamics is in good agreement with that of phenomenological Skyrme forces in the density region ρ/2short-range spin-orbit interaction. The strength function F(ρ) multiplying the square of the spin-orbit density comes out much larger than in phenomenological Skyrme forces and it has a pronounced density dependence.
Isospin violation in low-energy pion-nucleon scattering revisited
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, Martin, E-mail: hoferichter@hiskp.uni-bonn.d [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (IKP-3), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2010-02-01
We calculate isospin breaking in pion-nucleon scattering in the threshold region in the framework of covariant baryon chiral perturbation theory. All effects due to quark mass differences as well as real and virtual photons are consistently included. As an application, we discuss the energy dependence of the triangle relation that connects elastic scattering on the proton pi{sup +}-p->pi{sup +}-p with the charge exchange reaction pi{sup -}p->pi{sup 0}n.
Isospin violation in low-energy pion-nucleon scattering revisited
International Nuclear Information System (INIS)
Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.
2010-01-01
We calculate isospin breaking in pion-nucleon scattering in the threshold region in the framework of covariant baryon chiral perturbation theory. All effects due to quark mass differences as well as real and virtual photons are consistently included. As an application, we discuss the energy dependence of the triangle relation that connects elastic scattering on the proton π ± p→π ± p with the charge exchange reaction π - p→π 0 n.
N → Δ (1232) electromagnetic transition form factor and pion-nucleon dynamics at moderate energies
International Nuclear Information System (INIS)
Jurewicz, A.
1980-01-01
The dependence of the electromagnetic N → Δ (1232) transition form factor G/sup asterisk//sub M/(q 2 ) on q 2 , the four-momentum transfer squared, has been calculated with the use of relativistic dispersion relations supplemented with some dynamical assumptions. In the first place, they regard the phase of the magnetic dipole amplitude of electroproduction of pions on nucleons in the p 33 final state beyond the region of elastic unitarity. Namely, over the range from the lowest inelastic threshold up to 1780 MeV pion-nucleon c.m. energy, the phase in question has been identified with the real part of the respective phase shift of pion-nucleon scattering. Secondly, contributions to the dispersion integral from the higher energy region have been neglected. Finally, the polynomial ambiguity which appears in the problem has been fixed by requiring that the foregoing amplitude of electroproduction vanishes, independently of q 2 , at the upper end of the integration interval as defined above. These assumptions which preserve unitarity were shown previously to lead to very good results when applied to the calculation of the multipole amplitudes M/sup() 3/2/ 1 /sub +/ and E/sup() 3/2/ 1 /sub +/ of photopion production on nucleons in the Δ (1232) region. Now it is also shown that G/sup asterisk//sub M/(q 2 ) calculated in that fashion follows remarkably well the data over the whole range 0 2 2 currently covered by quantitative experimental studies. Some speculation concerning a possible dynamical rooting of the foregoing assumptions is presented
Forward pion-nucleon charge exchange reaction and Regge constraints
International Nuclear Information System (INIS)
Huang Fei; Sibirtsev, A.; Krewald, S.; Hanhart, C.; Haidenbauer, J.; Meibner, U.-G.
2009-01-01
We present our recent study of pion-nucleon charge exchange amplitudes above 2 GeV. We analyze the forward pion-nucleon charge exchange reaction data in a Regge model and compare the resulting amplitudes with those from the Karlsruhe-Helsinki and George-Washington-University partial-wave analyses. We explore possible high-energy constraints for theoretical baryon resonance analyses in the energy region above 2 GeV. Our results show that for the pion-nucleon charge exchange reaction, the appropriate energy region for matching meson-nucleon dynamics to diffractive scattering should be around 3 GeV for the helicity flip amplitude. (authors)
International Nuclear Information System (INIS)
Kondratyuk, S.; Kubodera, K.; Myhrer, F.; Scholten, O.
2004-01-01
The Adler-Weisberger and Goldberger-Miyazawa-Oehme sum rules are calculated within a relativistic, unitary and crossing symmetric dynamical model for pion-nucleon scattering using two different methods: (1) by evaluating the scattering amplitude at the corresponding low-energy kinematics and (2) by evaluating the sum-rule integrals with the calculated total cross section. The discrepancy between the results of the two methods provides a measure of the breaking of analyticity and chiral symmetry in the model. The contribution of the Δ resonance, including its dressing with meson loops, is discussed in some detail and found to be small
Pion-nucleon scattering: from chiral perturbation theory to Roy-Steiner equations
Kubis, Bastian; Hoferichter, Martin; de Elvira, Jacobo Ruiz; Meißner, Ulf-G.
2016-11-01
Ever since Weinberg's seminal predictions of the pion-nucleon scattering amplitudes at threshold, this process has been of central interest for the study of chiral dynamics involving nucleons. The scattering lengths or the pion-nucleon σ-term are fundamental quantities characterizing the explicit breaking of chiral symmetry by means of the light quark masses. On the other hand, pion-nucleon dynamics also strongly affects the long-range part of nucleon-nucleon potentials, and hence has a far-reaching impact on nuclear physics. We discuss the fruitful combination of dispersion-theoretical methods, in the form of Roy-Steiner equations, with chiral dynamics to determine pion-nucleon scattering amplitudes at low energies with high precision.*
Nuclear energy density functional from chiral pion-nucleon dynamics revisited
Kaiser, N.; Weise, W.
2009-01-01
We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from $1\\pi$-exchange, iterated $1\\pi$-exchange, and irreducible $2\\pi$-exchange with intermediate $\\Delta$-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass $M^*(\\rho)$ entering the energy density functional is iden...
Low-energy pion-nucleon scattering
International Nuclear Information System (INIS)
Gibbs, W.R.; Ai, L.; Kaufmann, W.B.
1998-01-01
An analysis of low-energy charged pion-nucleon data from recent π ± p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f 2 =0.0756±0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P 31 and P 13 partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the Σ term. Off-shell amplitudes are also provided. copyright 1998 The American Physical Society
Pion-nucleon scattering and isospin violation
International Nuclear Information System (INIS)
Meissner, U.G.
1999-01-01
The paper discusses low-energy pion-nucleon scattering in the framework of chiral perturbation theory. It is argued that using this theoretical method one is able to match the in some cases impressive experimental accuracy (for the low partial waves). It is also shown how strong and electromagnetic isospin violation can be treated simultaneously. Some first results for neutral pion scattering and the σ-term are given. Copyright (1999) World Scientific Publishing Co. Pte. Ltd
Remarks on the pion-nucleon σ-term
Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.
2016-09-01
The pion-nucleon σ-term can be stringently constrained by the combination of analyticity, unitarity, and crossing symmetry with phenomenological information on the pion-nucleon scattering lengths. Recently, lattice calculations at the physical point have been reported that find lower values by about 3σ with respect to the phenomenological determination. We point out that a lattice measurement of the pion-nucleon scattering lengths could help resolve the situation by testing the values extracted from spectroscopy measurements in pionic atoms.
Isospin breaking in the pion-nucleon scattering lengths
International Nuclear Information System (INIS)
Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.
2009-01-01
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Isospin breaking in the pion-nucleon scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, Martin [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (Theorie), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2009-07-06
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
[Measurements of observables of pion-nucleon reactions]. Progress report
International Nuclear Information System (INIS)
Sadler, M.E.
1985-01-01
This document reports the progress of the research of pion reactions. These include (1) a study to measure observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross section measurements at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π +- on 3 H and 3 He. Individual experiments will be indexed separately
Pion-nucleon vertex function with one nucleon off shell
International Nuclear Information System (INIS)
Mizutani, T.; Rochus, P.
1979-01-01
The pion-nucleon vertex function with an off-mass-shell nucleon is obtained through sideways dispersion relations with the P 11 and S 11 pion-nucleon phase shifts as only input. Contrary to the recent calculation of Nutt and Shakin, we find that the proper and improper vertex functions behave quite differently, indicating the importance of the nucleon propagator dressing. In particular the proper vertex function is found to have two poles in the unphysical region
Charge dependence of the pion-nucleon coupling constant
Directory of Open Access Journals (Sweden)
V. A. Babenko
2015-07-01
Full Text Available On the basis of the Yukawa potential we study the pion-nucleon coupling constants for the neutral and charged pions assuming that nuclear forces at low energies are mainly determined by the exchange of virtual pions. We obtain the charged pseudovector pion-nucleon coupling constant f2π± = 0.0804(7 by making the use of experimental low-energy scattering parameters for the singlet pp- and np-scattering, and also by use of the neutral pseudovector pion-nucleon coupling constant f2π0 = 0.0749(7. Corresponding value of the charged pseudoscalar pion-nucleon coupling constant g2π0 / 4π = 14.55(13 is also determined. This calculated value of the charged pseudoscalar pion-nucleon coupling constant is in fully agreement with the experimental constant g2π0 / 4π = 14.52(26 obtained by the Uppsala Neutron Research Group. Our results show considerable charge splitting of the pion-nucleon coupling constant.
Doorway-resonance model for pion-nucleon D- and F-wave scattering
International Nuclear Information System (INIS)
Ernst, D.J.; Parnell, G.E.; Assad, C.; Texas A and M Univ., College Station, TX
1990-01-01
A model for the resonant pion-nucleon D- and F-waves is developed which assumes that the pion-plus-nucleon couples to a resonance and that the resonance can serve as a doorway to the inelastic channels. With the use of simple form factors, the model is capable of reproducing the pion-nucleon phase shifts up to an energy of T π =1.4 GeV if the coupling of the elastic channel to the inelastic channels is taken from data as input into the model. A value for the mass of the resonance that would result in the absence of the coupling to decay channels is extracted from the data utilizing the model. This is the mass that is most easily modeled by bag models. For the non-resonant D- and F-wave channels a separable potential model is used. This model, like the resonance model, is developed utilizing the invariant amplitude which is free of kinematic singularities and uses invariant norms and phase spaces. The model is also applied to the S-wave channels. A relation between the resonance model and the Chew-Low model is discovered and used to derive an extended Chew-Low model which is applied to the P 13 , P 31 and P 33 channels. Implications of the model for understanding the range of the pion-nucleon interaction and the dynamic structure of the interaction are presented. (orig.)
Roy-Steiner-equation analysis of pion-nucleon scattering
Meißner, U.-G.; Ruiz de Elvira, J.; Hoferichter, M.; Kubis, B.
2017-03-01
Low-energy pion-nucleon scattering is relevant for many areas in nuclear and hadronic physics, ranging from the scalar couplings of the nucleon to the long-range part of two-pion-exchange potentials and three-nucleon forces in Chiral Effective Field Theory. In this talk, we show how the fruitful combination of dispersion-theoretical methods, in particular in the form of Roy-Steiner equations, with modern high-precision data on hadronic atoms allows one to determine the pion-nucleon scattering amplitudes at low energies with unprecedented accuracy. Special attention will be paid to the extraction of the pion-nucleon σ-term, and we discuss in detail the current tension with recent lattice results, as well as the determination of the low-energy constants of chiral perturbation theory.
Relativistic generalizations of simple pion-nucleon models
International Nuclear Information System (INIS)
McLeod, R.J.; Ernst, D.J.
1981-01-01
A relativistic, partial wave N/D dispersion theory is developed for low energy pion-nucleon elastic scattering. The theory is simplified by treating crossing symmetry only to lowest order in the inverse nucleon mass. The coupling of elastic scattering to inelastic channels is included by taking the necessary inelasticity from experimental data. Three models are examined: pseudoscalar coupling of pions and nucleons, pseudovector coupling, and a model in which all intermediate antinucleons are projected out of the amplitude. The phase shifts in the dominant P 33 channel are quantitatively reproduced for P/sub lab/ 33 phase shifts. Thus a model of the pion-nucleon interaction which does not include antinucleon degrees of freedom is found to be unphysical
Low energy pion--nucleon and pion--deuteron interactions
International Nuclear Information System (INIS)
Burman, R.L.
1975-01-01
This survey concentrates upon current experiments in the fields of pion-nucleon and pion-deuteron interactions, for low-energy incident pions--below 300 MeV. The discussion is restricted to very recent work. The topics to be covered are: π +- p → π +- p, Elastic Scattering; π +- p → π +- pγ, Bremsstrahlung; π + d → pp, Absorption; π d → π + d, Elastic Scattering; and π + d → π + pn, Breakup. (14 figures) (U.S.)
A relativistic, meson exchange model of pion-nucleon scattering
International Nuclear Information System (INIS)
Pearces, B.C.; Jennings, B.K.
1990-06-01
A relativistic meson exchange approach to the pion-nucleon interaction is developed using a three-dimensional relativistic two-body propagator, and the results using different propagators are compared. The relativistic approach is able to describe low energy scattering up to 400 MeV above threshold, while preserving the soft pion theorems. The different propagators give similar results, as the form factors necessary to get a fit suppress much of the multiple scattering. (Author) (24 refs., 4 tabs., 6 figs.)
Determination of the pion-nucleon coupling constant
International Nuclear Information System (INIS)
Samaranayake, V.K.
1977-06-01
Forward dispersion relations are used to determine the pion-nucleon coupling constant and S-wave scattering lengths using a least squares fit with additional parameters introduced to take account of the uncertainties in the calculation of dispersion integrals. The values obtained are: f 2 = (78.0+- 2.1).10 -3 , a 1 -a 3 = (272.4+- 12.3).10 -3 , a 1 +2a 3 = (15.1+-10.4).10 -3
Pion-nucleon scattering in the chiral bag model
International Nuclear Information System (INIS)
Israilov, Z.Z.; Musakhanov, M.M.
1981-01-01
Pion-nucleon scattering in the (3.3) resonance region in the framework of chiral bag model(CBM) is considered. The effective Hamiltonian of πNΔ-system in the framework of the CBM contains πNN, πNΔ, πΔΔ interaction terms with the formfactor which is essentially dependent on the size and shape of the quark bag. The iteration of the Born graphs of this model provides successful description of the (3.3) and (3.1) scattering where the values of the parameters agree with CBM [ru
Static model calculation of pion-nucleon scattering
International Nuclear Information System (INIS)
Itoh, Takashi
1975-01-01
The p-wave pion-nucleon scattering phase-shifts are computed by the Chew-Low static model for pion incident energy of 0-300 MeV. The square of the unrenormalized coupling constant is taken to be f 2 =0.2, and the cutoff is made at k sub(max)=6μ. The computed 3,3 phase-shift passes through 90 deg about at the right energy. The other phase-shifts computed are small in rough agreement with experiment. (auth.)
Pion--nucleon sigma-commutator
International Nuclear Information System (INIS)
Banerjee, M.K.; Cammarata, J.B.
1977-07-01
The reasons for the large discrepancies in the magnitude of the πN sigma-commutator, sigma(πN), obtained by several authors are discussed using dynamic theory of the πN scattering amplitude. With sigma(πN) approximately 25 MeV this theory reproduces reasonably well both the experimental S-wave phase shifts at low energies and the amplitudes C approximately/sup(+)/(ν=0,t less than or equal to 0) determined by Langbein. In the method of Cheng and Dashen the value of sigma(πN) is obtained from these amplitudes by extrapolation to t = 2m 2 /sub π/. A study of the experimental D-wave ''scattering lengths'' implies that the coefficient of the term quadratic in t in the Hoehler expansion of C approximately/sup(+)/(0,t) is negative. Adding such a term to the results of the S-wave theory will tend to improve the agreement for C approximately/sup (+)/(0,t less than or equal to 0). These results suggest that the large ''world value'' sigma(πN) = 65 +- 5 MeV obtained using the Cheng-Dashen method is a consequence of errors in the extrapolation of amplitudes to the unphysical point ν = 0, t = 2m 2 /sub π/. Only the smaller value sigma(πN) approximately 25 MeV appears to be consistent with the experimental data and theoretical constraints
Pion-nucleon interactions in low energy region
International Nuclear Information System (INIS)
Hiroshige, Noboru; Tsujimura, Tadakuni.
1977-01-01
Pion-nucleon interactions in low energy region (below 320 MeV in kinetic energy) are investigated on the basis of the one-particle-exchange model. The model is directly compared with the experimental data, i.e., differential cross sections and recoil nucleon polarizations, since phase shifts have not been uniquely determined. It is shown that these experimental data can be well reproduced by taking account of N (nucleon), Δ 33 , N 11 , N 13 , rho, f 0 and S (scalar meson) in the intermediate state. Some comments are given on the coupling constants which are determined so as to minimize chi-squared value (chi 2 ). Our predicted phase shifts for s-, p- and d-waves are also compared with other authors'. (auth.)
Effective pion--nucleon interaction in nuclear matter
International Nuclear Information System (INIS)
Celenza, L.S.; Liu, L.C.; Nutt, W.; Shakin, C.M.
1976-01-01
We discuss the modification of the interaction between a pion and a nucleon in the presence of an infinite medium of nucleons (nuclear matter). The theory presented here is covariant and is relevant to the calculation of the pion--nucleus optical potential. The specific effects considered are the modifications of the nucleon propagator due to the Pauli principle and the modification of the pion and nucleon propagators due to collisions with nucleons of the medium. We also discuss in detail the pion self-energy in the medium, paying close attention to off-shell effects. These latter effects are particularly important because of the rapid variation with energy of the fundamental pion--nucleon interaction. Numerical results are presented, the main feature being the appearance of a significant damping width for the (3, 3) resonance
Extraction of the pion-nucleon sigma-term from the spectrum of exotic baryons
International Nuclear Information System (INIS)
Schweitzer, P.
2004-01-01
The pion-nucleon sigma-term is extracted on the basis of the soliton picture of the nucleon from the mass spectrum of usual and the recently observed exotic baryons, assuming that they have positive parity. The value found is consistent with that inferred by means of conventional methods from pion-nucleon scattering data. The study can also be considered as a phenomenological consistency check of the soliton picture of baryons. (orig.)
Pion-nucleon vertex function and the Chew-Low model
International Nuclear Information System (INIS)
Nutt, W.T.
1977-01-01
We provide an interpretation of the cutoff function used in the Chew-Low theory of pion-nucleon scattering. It is shown that this function may be related to the pion-pion interaction which is not explicitly considered in the Chew-Low approach. Using a previously developed model for the pion-nucleon vertex function, we then perform a ''parameter-free'' Chew-Low calculation which predicts the P 33 resonance quite well
Theory of the low-energy pion-nucleon interaction
International Nuclear Information System (INIS)
Banerjee, M.K.; Cammarata, J.B.
1978-01-01
A once-subtracted form of the Low equation for the pion-nucleon scattering amplitude is derived, with partial conservation of axial-vector current used to define the amplitude when one pion is off the mass shell. The static approximation is not made and both the seagull terms and the antinucleon contribution (z graphs) are retained. The theory is applied to calculate the S-wave amplitudes in the elastic scattering region. Good agreement is found with the phase shift fits to the data when we use vertical-barg/sub π/(4M 2 ) vertical-bar = 11.69 and 25.5 MeV for the πN sigma commutator. The implications of this work for the analysis of low-energy elastic scattering of pions form nuclei are discussed. In particular, we point out how this work establishes the presence of a Laplacian term in the pion-nucleus optical potential with a magnitude that is fixed from the value of the sigma commutator
Reconciling threshold and subthreshold expansions for pion-nucleon scattering
Siemens, D.; Ruiz de Elvira, J.; Epelbaum, E.; Hoferichter, M.; Krebs, H.; Kubis, B.; Meißner, U.-G.
2017-07-01
Heavy-baryon chiral perturbation theory (ChPT) at one loop fails in relating the pion-nucleon amplitude in the physical region and for subthreshold kinematics due to loop effects enhanced by large low-energy constants. Studying the chiral convergence of threshold and subthreshold parameters up to fourth order in the small-scale expansion, we address the question to what extent this tension can be mitigated by including the Δ (1232) as an explicit degree of freedom and/or using a covariant formulation of baryon ChPT. We find that the inclusion of the Δ indeed reduces the low-energy constants to more natural values and thereby improves consistency between threshold and subthreshold kinematics. In addition, even in the Δ-less theory the resummation of 1 /mN corrections in the covariant scheme improves the results markedly over the heavy-baryon formulation, in line with previous observations in the single-baryon sector of ChPT that so far have evaded a profound theoretical explanation.
Roy-Steiner equations for pion-nucleon scattering
Ditsche, C.; Hoferichter, M.; Kubis, B.; Meißner, U.-G.
2012-06-01
Starting from hyperbolic dispersion relations, we derive a closed system of Roy-Steiner equations for pion-nucleon scattering that respects analyticity, unitarity, and crossing symmetry. We work out analytically all kernel functions and unitarity relations required for the lowest partial waves. In order to suppress the dependence on the high energy regime we also consider once- and twice-subtracted versions of the equations, where we identify the subtraction constants with subthreshold parameters. Assuming Mandelstam analyticity we determine the maximal range of validity of these equations. As a first step towards the solution of the full system we cast the equations for the π π to overline N N partial waves into the form of a Muskhelishvili-Omnès problem with finite matching point, which we solve numerically in the single-channel approximation. We investigate in detail the role of individual contributions to our solutions and discuss some consequences for the spectral functions of the nucleon electromagnetic form factors.
Studying the Puzzle of the Pion Nucleon Sigma Term
Kane, Christopher; Lin, Huey-Wen
2017-09-01
The pion nucleon sigma term (σπN) is a fundamental parameter of QCD and is integral in the experimental search for dark matter particles as it is used to calculate the cross section of interactions between potential dark matter candidates and nucleons. Recent calculations of this term from lattice-QCD data disagree with calculations done using phenomenological data. This disparity is large enough to cause concern in the dark matter community as it would change the constraints on their experiments. We investigate one potential source of this disparity by studying the flavor dependence on LQCD data used to calculate σπN. To calculate σπN, we study the nucleon mass dependence on the pion mass and implement the Hellmann-Feynman Theorem. Previous calculations only consider LQCD data that accounted for 2 and 3 of the lightest quarks in the quark sea. We extend this study by using new high statistic data that considers 2, 3, and 4 quarks in the quark sea to see if the exclusion of the heavier quarks can account for this disparity. National Science Foundation.
Relativistic quantum kinetic analysis of a pion--nucleon system
International Nuclear Information System (INIS)
Alonso, J.D.
1985-01-01
A relativistic plasma of nucleons interacting through pions via the usual isospin-invariant Yukawa coupling is analyzed in the framework of the covariant Wigner function technique. The method is manifestly covariant and the temperature effects are considered. The relativistic quantum BBGKY hierarchy for the pion--nucleon system is derived. By generalizing the Bogolioubov analysis of the classical BBGKY hierarchy a non-perturbative renormalizable method is elaborated which allows the solution of the kinetic problem in form of power series of two cluster parameters which measure the importance of correlations. In the lowest order of the cluster expansion (Hartree approximation of zero-order approximation) the quasi-nucleon Fock space is introduced, the fermion Wigner function in the thermodynamic equilibrium is obtained and the vacuum effects are renormalized. In this approximation the plasma behaves as a perfect Fermi gas of nucleons and antinucleons, but there exists an abnormal configuration with a uniform pion condensate which is unstable. In the next approximation (quadratic in the small parameters) the quasi-pion dispersion relation is obtained and the vacuum polarization tensor is renormalized. The quasi-pion rest-mass spectra (''plasma frequency'') and the effective-coupling behaviour as functions of the thermodynamic state are given. By estimating the size of the cluster parameters the self-consistency of the approximation scheme is proved. The quasi-pion Fock space is introduced and the quasi-pion equilibrium Wigner function is obtained. From these results the problem of the higher-order corrections to the Hartree thermodynamics is outlined
Isospin breaking in the pion-nucleon coupling constant and the nucleon-nucleon scattering length
Directory of Open Access Journals (Sweden)
V. A. Babenko
2016-08-01
Full Text Available Charge independence breaking (CIB in the pion-nucleon coupling constant and the nucleon-nucleon scattering length is considered on the basis of the Yukawa meson theory. CIB effect in these quantities is almost entirely explained by the mass difference between the charged and the neutral pions. Therewith charge splitting of the pion-nucleon coupling constant is almost the same as charge splitting of the pion mass. Calculated difference between the proton-proton and the neutron-proton scattering length in this case comprises ∼90% of the experimental value.
International Nuclear Information System (INIS)
Korpa, C.L.; Lutz, M.F.M.; Technische Univ. Darmstadt
2003-06-01
We evaluate the in-medium spectral functions for pions, nucleon and isobar resonances in a self consistent and covariant manner. The calculations are based on a recently developed formulation which leads to predictions in terms of the pion-nucleon scattering phase shifts and a set of Migdal parameters describing important short range correlation effects. We do not observe any significant softening of pion modes if we insist on reasonable isobar resonance properties but predict a considerable broadening of the N(1440) and N(1520) resonances in nuclear matter. (orig.)
Calculation of the pion-nucleon double spectral functions and applications
International Nuclear Information System (INIS)
Grether, D.
1986-01-01
In the present thesis the latest results from pion-pion and pion-nucleon phase analyses are applied in order to calculate the pion-nucleon double spectral functions which belong to the elastic unitarity in the t-channel. The equivalence of the partial wave projection of these spectral functions in the s-channel with the elastic t-channel unitarity is extensively discussed. After we summarize the aspects of the pion-nucleon system seeming in this connection interesting we discuss the Mandelstam method for the calculation of the spectral functions by means of the elastic t-channel unitarity as well as the applied input and present the results. Thereafter we use these results in order to calculate by means of a fixed t-channel dispersion relation the real parts of the t-channel cuts. Partial wave projections into the t-channel are proved as equivalent to the elastic t-channel unitarity. We study the compatibility of the asymptotic behaviour of the spectral functions relative to the energy with current Regge pole models. Finally we use our results in order to calculate the pion-nucleon partial waves by means of their Froissart-Gribov representations which follow from their analyticity at fixed energy. (orig./HSI) [de
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1990-01-01
The LAMPF experiments have been performed in collaboration with UCLA, George Washington University, various groups at Los Alamos, and Catholic University. This paper discusses: a complete set of observables in the pion-nucleon system in the momentum interval 400-700 MeV/c; differential cross sections at low energy for pion-nucleon charge exchange; and elastic and inelastic scattering of π ± on 3 H and 3 He
S-wave pion-nucleon phase shifts in PADE approximation
International Nuclear Information System (INIS)
Achuthan, P.; Chandramohan, T.; Venkatesan, K.
1978-01-01
The two S-wave pion nucleon pahse shifts delta( 1 ) (I = 1/2) and delta( 3 ) (I = 3/2) have been calculated in the Pade approximation using epsilon(700), rho(770), f(1260), Δ(1236) and N(938) for the energy range W = 1085 MeV - 1820 MeV in the centre of mass. Contributions from suitable resonance combinations which agree nearest with the delta( 3 ) experimental values are given. (orig.) [de
Energy Technology Data Exchange (ETDEWEB)
Yao, De-Liang [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Siemens, D. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Bernard, V. [Groupe de Physique Théorique, Institut de Physique Nucléaire, UMR 8606,CNRS, University Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex (France); Epelbaum, E. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Gasparyan, A.M. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); SSC RF ITEP, Bolshaya Cheremushkinskaya 25, 117218 Moscow (Russian Federation); Gegelia, J. [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Tbilisi State University, 0186 Tbilisi (Georgia); Krebs, H. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Meißner, Ulf-G. [Helmholtz Institut für Strahlen- und Kernphysik andBethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany)
2016-05-05
We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P-partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.
Isospin breaking in pion-nucleon scattering at threshold by radiative processes
Ericson, Torleif Eric Oskar
2006-01-01
We investigate the dispersive contribution by radiative processes such as (pi- proton to neutron gamma) and (pi- proton to Delta gamma) to the pion-nucleon scattering lengths of charged pions in the heavy baryon limit. They give a large isospin violating contribution in the corresponding isoscalar scattering length, but only a small violation in the isovector one. These terms contribute 6.3(3)% to the 1s level shift of pionic hydrogen and give a chiral constant F_pi^2f_1=-25.8(8) MeV.
Extracting the σ-term from low-energy pion-nucleon scattering
Ruiz de Elvira, Jacobo; Hoferichter, Martin; Kubis, Bastian; Meißner, Ulf-G.
2018-02-01
We present an extraction of the pion-nucleon (π N) scattering lengths from low-energy π N scattering, by fitting a representation based on Roy-Steiner equations to the low-energy data base. We show that the resulting values confirm the scattering-length determination from pionic atoms, and discuss the stability of the fit results regarding electromagnetic corrections and experimental normalization uncertainties in detail. Our results provide further evidence for a large π N σ-term, {σ }π N=58(5) {{MeV}}, in agreement with, albeit less precise than, the determination from pionic atoms.
A phenomenological determination of the pion-nucleon scattering lengths from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2005-01-01
A model independent expression for the electromagnetic corrections to a phenomenological hadronic pion-nucleon scattering length, extracted from pionic hydrogen, is obtained. In a non-relativistic approach and using an extended charge distribution, these corrections are derived up to terms of order (alpha)**2 log(alpha) in the limit of a short-range hadronic interaction. We infer a charged pion-proton scattering length of 0.0870(5) in units of inverse pion mass, which gives for the charged pion-proton-neutron coupling, through the GMO relation, a value of 14.04(17).
Phase shift analysis of pion-nucleon elastic scattering from the threshold to 2.5 GeV
International Nuclear Information System (INIS)
Ayed, Rachid.
1976-10-01
An energy-independent phase-shift analysis of pion-nucleon elastic scattering is performed from threshold to 2.5 GeV/c 2 masses. It uses a coherent set of data (cross sections and polarizations for the 3 final states: π + p, π - p and π 0 n) constructed from a considerable number (approximately 30000) of experimental points. Empirical criteria of smoothness behavior with energy of the partial waves allowed to obtain a unique solution, i.e. one set of phases shifts (up to I waves) at each energy. The consistency of the solution has been checked by a dispersion relation on the B invariant amplitude. The partial amplitudes obtained have been fitted separately, as a function of energy, in order to extract resonance from background. New resonances of small elasticity have been identified. Parameters (mass, width and elasticity) of all resonant states are given. A dynamical interpretation of the resonance is discussed and their recurrence in the Chew-Frautschi plot are shown [fr
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1990-01-01
This report discusses the following: pion-nucleon program; a search for neutral pions from the spontaneous fission of 252 Cf; elastic and inelastic pion scattering on 3 H and 3 He; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral B mesons; measurement of π - p → π 0 n in the cusp region at the Leningrad Nuclear Physics Institute (LNPI); a test of consistency of low-energy pion-nucleon differential cross sections with total cross sections; and design of a high energy photon calorimeter for the neutral meson spectrometer
Charge exchange during pion-nucleon scattering at low energy: experiment and analysis
International Nuclear Information System (INIS)
Vernin, Pascal
1972-01-01
This research thesis lies within the frame of a more general study of pion-nucleon scattering according to the following processes: π + p → π + p; π - p → π - p; π - p → π 0 n. It more precisely addresses the last reaction, so-called charge exchange. Pion-nucleon interactions are described by phase shifts of scattering waves. But the measurement of one of these phase shifts (that of the S wave) requires very low energy pions, and could not have been performed until now with a good precision. In order to fill this gap, the author performed charge exchange experiments at 180 deg. and for energies of 22.6, 33.9 and 42.6 MeV. After a recall on involved theoretical data, the author describes the experimental setup, and reports the detailed study of problems raised by neutron detection. He shows that the analysis of experimental data allows (a 3 - a 1 ) to be obtained with a precision which, without being as high as desired, is nevertheless satisfying [fr
Determination of the pion-nucleon coupling constant and scattering lengths
Ericson, Torleif Eric Oskar; Thomas, A W
2002-01-01
We critically evaluate the isovector GMO sum rule for forward pion-nucleon scattering using the recent precision measurements of negatively charged pion-proton and pion-deuteron scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data a pseudoscalar coupling constant of 14.17+-0.05(statistical)+-0.19(systematic) or a pseudovector one of 0.0786(11). This value is intermediate between that of indirect methods and the direct determination from backward neutron-proton differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the negatively charged pion-proton and pion-neutron scattering lengths with high precision. The symmetric sum gives 0.0017+-0.0002(statistical)+-0.0008 (systematic) and the antisymmetric one 0.0900+-0.0003(statistical)+-0.0013(systematic), both in units of inverse charged pi...
Energy Technology Data Exchange (ETDEWEB)
Araujo, Vanilse da Silva
1997-12-31
In this work we study the effects of chiral symmetry in the pion-nucleon coupling constant in the context of the linear {sigma}- model. First, we introduce the linear {sigma}-model and we discuss the phenomenological hypothesis of CVC and PCAC. Next, we calculate the coupling constant g+{pi}{sub NN}(q{sup 2}) and the nucleon pionic mean square radius considering the contribution of all the diagrams up to one-loop in the framework of the linear {sigma}-model for different values of the mass of the sigma meson and we compare them with the phenomenological form factors. Finally we make an extension of the linear {sigma}-model that consists of taking into account the mass differences of ions and nucleons into the Lagrangian of the model, to study the change dependence of g{sub {pi}nn} (q{sup 2}) and of the mean square radius. (author) 21 refs., 17 figs., 4 tabs.
International Nuclear Information System (INIS)
Coon, S.A.; Scadron, M.D.
1981-01-01
We suggest that the observed 6% Goldberger-Treiman discrepancy is due in part to a 3% variation in the pion-nucleon form factor and in part due to a 3% variation in the pion decay form factor from q 2 =m/sub π/ 2 to q 2 =0
Pion-nucleon form factor in the Chew-Low theory
International Nuclear Information System (INIS)
Ernst, D.J.; Johnson, M.B.
1978-01-01
We find a solution to the static Chew-Low theory of pion-nucleon scattering, avoiding the ''one-meson approximation.'' Our basic equation is crossing symmetric and may be solved for phase shifts delta (p) by standard numerical techniques, upon specifying a form factor v (p) and a set of inelasticities. With v (p) = exp(-p 2 /30) we reproduce experimental delta (p) for p/sub L/ < or = 1.2 GeV/c in the (3,3) state; in the (1,3) states and (3,1) states delta (p) compare well on the average but in the (1,1) state delta (p) have opposite signs. We show the importance of crossing symmetry and the coupling to inelastic channels, and we discuss the possibility of determining v (p) directly from elastic scattering by an inverse scattering formula
High-Precision Determination of the Pion-Nucleon σ Term from Roy-Steiner Equations
Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.
2015-08-01
We present a determination of the pion-nucleon (π N ) σ term σπ N based on the Cheng-Dashen low-energy theorem (LET), taking advantage of the recent high-precision data from pionic atoms to pin down the π N scattering lengths as well as of constraints from analyticity, unitarity, and crossing symmetry in the form of Roy-Steiner equations to perform the extrapolation to the Cheng-Dashen point in a reliable manner. With isospin-violating corrections included both in the scattering lengths and the LET, we obtain σπ N=(59.1 ±1.9 ±3.0 ) MeV =(59.1 ±3.5 ) MeV , where the first error refers to uncertainties in the π N amplitude and the second to the LET. Consequences for the scalar nucleon couplings relevant for the direct detection of dark matter are discussed.
Matching Pion-Nucleon Roy-Steiner Equations to Chiral Perturbation Theory
Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.
2015-11-01
We match the results for the subthreshold parameters of pion-nucleon scattering obtained from a solution of Roy-Steiner equations to chiral perturbation theory up to next-to-next-to-next-to-leading order, to extract the pertinent low-energy constants including a comprehensive analysis of systematic uncertainties and correlations. We study the convergence of the chiral series by investigating the chiral expansion of threshold parameters up to the same order and discuss the role of the Δ (1232 ) resonance in this context. Results for the low-energy constants are also presented in the counting scheme usually applied in chiral nuclear effective field theory, where they serve as crucial input to determine the long-range part of the nucleon-nucleon potential as well as three-nucleon forces.
The pion-nucleon form factor in space- and time-like regions
International Nuclear Information System (INIS)
Speth, J.; Tegen, R.
1990-01-01
We investigate the pion-nucleon vertex function in space- and time-like regions; these vertex functions appear as internal vertices in nucleon-antinucleon annihilations into n pions (n=2, 3, ..., 6). It is emphasised that only relativistic quark models can account for these vertices where one of the baryons/antibaryons is far off-shell with total energy close to zero. Using a novel 4-momentum projection technique we obtain results which generalize the usual (Breit frame) calculation of G πNN (k 2 ) (space-like) thereby removing completely the discrepancy in the Goldberger-Treiman relation. Our relativistic quark model calculation also explains the empirical suppression of antibaryonic contributions to the vertex functions Gsub(πNanti B) and Gsub(πBanti N) which enter in processes like Nanti N→ππ. (orig.)
International Nuclear Information System (INIS)
Sadler, M.E.
1986-03-01
Progress is reported for the past year in pion scattering programs. The measurements include: (1) a complete set of observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π +- on 3 H and 3 He. The experiments are conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF)
International Nuclear Information System (INIS)
Sadler, M.E.
1989-01-01
This report describes the pion scattering programs in which Abilene Christian University collaborated under this contract which ended May 14, 1988. The experiments were conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF). The experiments were performed in collaboration with UCLA, George Washington University, LAMPF Groups MP-4, MP-10 and MP-13, and Catholic University. The measurements included: (1) a complete set of observables in the pion-nucleon system in the momentum interval 400--700 MeV/c, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π ± on 3 H and 3 He
Determination of the pion-nucleon coupling constant and scattering lengths
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Thomas, A.W.
2002-01-01
We critically evaluate the isovector Goldberger-Miyazawa-Oehme (GMO) sum rule for forward πN scattering using the recent precision measurements of π - p and π - d scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data, g c 2 (GMO)/4π=14.11±0.05(statistical)±0.19(systematic) or f c 2 /4π=0.0783(11). This value is intermediate between that of indirect methods and the direct determination from backward np differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the pion-proton and pion-neutron scattering lengths with high precision, namely, (a π - p +a π - n )/2=[-12±2(statistical)±8(systematic)]x10 -4 m π -1 and (a π - p -a π - n )/2=[895±3(statistical)±13 (systematic)]x10 -4 m π -1 . For the need of the present analysis, we improve the theoretical description of the pion-deuteron scattering length
Moresi, Louis
2015-04-01
Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1992-01-01
This report discusses research on the following topics: pion-nucleon interactions; detector tomography facility; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral D and B mesons; N* collaboration at CEBAF; and pilac experiments
Quantum dynamical entropy revisited
International Nuclear Information System (INIS)
Hudetz, T.
1996-10-01
We define a new quantum dynamical entropy, which is a 'hybrid' of the closely related, physically oriented entropy introduced by Alicki and Fannes in 1994, and of the mathematically well-developed, single-argument entropy introduced by Connes, Narnhofer and Thirring in 1987. We show that this new quantum dynamical entropy has many properties similar to the ones of the Alicki-Fannes entropy, and also inherits some additional properties from the CNT entropy. In particular, the 'hybrid' entropy interpolates between the two different ways in which both the AF and the CNT entropy of the shift automorphism on the quantum spin chain agree with the usual quantum entropy density, resulting in even better agreement. Also, the new quantum dynamical entropy generalizes the classical dynamical entropy of Kolmogorov and Sinai in the same way as does the AF entropy. Finally, we estimate the 'hybrid' entropy both for the Powers-Price shift systems and for the noncommutative Arnold map on the irrational rotation C * -algebra, leaving some interesting open problems. (author)
International Nuclear Information System (INIS)
Safronov, A.N.
2007-01-01
Full text: The pion-nucleon dynamics is one of the most fundamental problems in nuclear and particle physics. It is now widely believed that QCD is fundamental theory of strong interactions. On this basis all hadron-hadron interactions are completely determined by the underlying quark-gluon dynamics. However, due to the formidable mathematical problems raised by the non-perturbative character of QCD at low and intermediate energies, we are still far from a quantitative understanding hadron-hadron interactions from this point of view. Recently the relativistic approaches to constructing effective interaction operators between strongly interacting composite particles has been proposed on the basis of analytic S-matrix theory and methods for solving the inverse quantum scattering problem. The kernel of Marchenko equation in theory of inverse scattering problem can be expressed in terms of the discontinuity of the partial wave amplitude on dynamic cut in the complex s=k 2 plane, k being the relative momentum of colliding particles. The discontinuities of partial-wave amplitudes are determined by model-independent quantities (renormalized vertex constants and amplitudes of sub-processes involving on-mass-shell particles off physical region) and can be calculated by methods of relativistic quantum field theory within various dynamical approaches. In particular, effective field theory can be used to calculate the discontinuities across dynamical cuts closest to physical region. In present work a new manifestly Poincare-invariant approach to solving the inverse scattering problem is developed with allowance for inelasticity effects. The equations of the N/D method are used as dynamical equations in this approach. With the help of N/D-equations it was earlier shown that solution of a scattering problem in case of nonzero angular momentum does not exist for arbitrary discontinuity of partial-wave amplitude. The method is elaborated allowing to determine contributions of
International Nuclear Information System (INIS)
Sadler, M.E.
1984-01-01
This study is a continuation of the pion-nucleon program at the Los Alamos Meson Physics Facility. Previous measurements, in chronological order, have included differential cross sections for π/sup +-/p elastic scattering at P/sub π/ = 378 - 687 MeV/c (LAMPF experiment 363), π - p charge exchange for P/sub π/ = 247 - 687 MeV/c (LAMPF experiment 120), and measurements of the polarization asymmetry for π/sup +-/p -> π/sup +-/p and π - p -> π 0 n for P/sub π/ = 471 - 687 MeV/c (LAMPF experiments 120* and 120**, respectively). Two experiments were initiated in the past year, forward-angle differential cross sections for π - p -> π 0 n at P/sub π/ = 96 - 150 MeV/c (LAMPF experiment 809) and polarization asymmetry for π - p - > γn (LAMPF experiment 804). Approved experiments which will be scheduled in the future are spin rotation measurements for π/sup +-/p -> π/sup +-/p (LAMPF experiments 806 and 807) and differential cross sections for π - p -> π 0 n near 0 0 and 180 0 at P/sub π/ = 471-687 MeV/c (LAMPF experiment 849). Another experiment, differential cross section measurements for π/sup +-/ elastic scattering on 3 He and 3 H (LAMPF experiment 546), has also been completed. The 3 He and 3 H targets form an isospin doublet analogous to the proton and neutron. The I 3 = -1/2 member ( 3 H) of the multiplet can be utilized as a target in this case, allowing a direct test of charge symmetry not achievable in the πN system due to the impossibility of a pure neutron target
International Nuclear Information System (INIS)
Safronov, A.N.; Safronov, A.A.
2006-01-01
formation of a short-range repulsive core. In the given work this approach is generalized for constructing effective hadron-hadron interaction operators in framework multichannel formalism in arbitrary angular momentum states taking into account effects of inelasticity. The methods of taking into account mechanisms of formation a quark-gluon compound states in hadron-hadron interactions are elaborated also. The developed methods are applied to constructing nucleon-nucleon interaction operators in different partial-wave states. The boson-exchange model was used to calculate the discontinuities of the partial-wave scattering amplitudes taking into account π, σ, ρ, ω, η, a 0 -meson contributions. The effective nucleon-nucleon potentials in our approach (as against the one-boson-exchange model in usual sense) contain nonlinear contributions on dynamic discontinuities of partial-wave scattering amplitudes, which play essential role at small distances. Note that in realistic Bonn potential model [5] the short-range repulsion is due to ω-meson exchange contribution. It is required in this theory non-realistically large value (≅20 ) of the coupling constant g ωNN 2 /4π. The value of this coupling constant in our approach is consistent with available experimental data [6] and also with theoretical quark-model calculations. The theoretical predictions of the proposed approach are in fairly good agreement with partial-wave-analysis data for laboratory kinetic energies of incident nucleon up to T=1.5-2.0 GeV. The developed approach is applied also to pion-nucleon scattering at kinetic energies of incident pion up to T=2.0 GeV. This work was supported by the Russian Foundation for Basic Research under the project No 04-02-16967. (author)
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1989-01-01
This report summarizes the progress made from the end of the last reporting period (1 December 1987) to the present (1 March 1989) and presents future plans for the experimental programs in which Abilene Christian University is collaborating. The measurements include: a complete set of observables in the pion-nucleon system in the momentum interval 400--700 MeV/c, differential cross sections at low energy for pion-nucleon charge exchange, and elastic and inelastic scattering of π/sup +-/ on 3 H and 3 He
International Nuclear Information System (INIS)
Efrosinin, V.P.; Zaikin, D.A.
1983-01-01
Possible reasons of disagreement between estimates of the pion-nucleon σ term obtained by the method of dispersion relations with extrapolation to the Chang-Dashen point and by alternative methods, making no use of such extrapolation are investigated. One of the reasons may be, that the πN amplitude is not analytic in the variable t at ν=0. A method, which is not so strongly influenced by the nonanalyticity, is suggested to estimate the σ term making use of the threshold data for the πN amplitude. Relation between the scale and chiral invariance breakings is discussed and the resulting estimate of the σ term is presented. Both estimates give close results (42 and 34 MeV) which do not contradict one another within the uncertainties of the methods
International Nuclear Information System (INIS)
Efrosinin, V.P.; Zaikin, D.A.
1983-01-01
We study the possible reasons for the disagreement between the estimates of the pion-nucleon sigma term obtained by the method of dispersion relations with extrapolation to the Cheng-Dashen point and by other methods which do not involve this extrapolation. One reason for the disagreement may be the nonanalyticity of the πN amplitude in the variable t for ν = 0. We propose a method for estimating the sigma term using the threshold data for the πN amplitude, in which the effect of this nonanalyticity is minimized. We discuss the relation between scale invariance violation and chiral symmetry breaking and give the corresponding estimate of the sigma term. The two estimates are similar (42 and 34 MeV) and are in agreement when the uncertainties of the two methods are taken into consideration
International Nuclear Information System (INIS)
Sadler, M.E.
1987-03-01
This report describes the progress made in the past year in the pion scattering programs in which Abilene Christian University is collaborating. The measurements include (1) a complete set of observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/e, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π +- on 3 H and 3 He. Highlights of the progress in 1986 to 87 include (1) first measurement of the spin rotation parameters A and R for π +- p → π +- p scattering at 427 to 657 MeV/e, for which the principal investigator received support from Associated Western Universities (AWU) and ACU for sabbatical leave in Los Alamos, (2) final publication of the data for the differential cross sections and analyzing powers for π +- p elastic scattering at 378 to 687 MeV/c, (3) final publication of forward-angle differential cross sections for π - p → π 0 n at 101 to 147 MeV/c, and (4) continued development of analysis capabilities on the ACU VAX-11/785, including full implementation of the LAMPF Q system MAPPER and DISSPLA graphics software. TEDI and TEX word processing and the associated hardware to utilize the software. The experiments are conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF). The experiments are performed in collaboration with UCLA, George Washington University, LAMPF Groups MP-4, MP-10 and MP-13, and Catholic University. 37 refs., 13 figs., 1 tab
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1987-01-01
This report describes the progress made in the past year and future plans for the pion scattering programs in which Abilene Christian University is collaborating. The experiments are conducted at the Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF). The experiments are performed in collaboration with UCLA, George Washington University, LAMPF Groups MP-4, MP-10 and MP-13, and Catholic University. The measurements include: (1) a complete set of observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross sections at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π/sup +-/ on 3 H and 3 He
Narrow coherent effects in πNN-dynamics
International Nuclear Information System (INIS)
Kudryavtsev, A.E.; Obrant, G.Z.
1990-01-01
Coherent effect production is considered in πNN-dynamics with resonant pion-nucleon interaction via Brueckner theory and Faddev equations. It is shown that the narrow energy and final momentum dependence can arise in the inelastic S-wave πd-scattering. The energy dependence peculiarities can have a width an order magnitude less than πN-resonance one
Dynamics of Shape Fluctuations of Quasi-spherical Vesicles Revisited
DEFF Research Database (Denmark)
Miao, L.; Lomholt, Michael Andersen; Kleis, J.
2002-01-01
In this paper, the dynamics of spontaneous shape fluctuations of a single, giant quasi-spherical vesicle formed from a single lipid species is revisited theoretically. A coherent physical theory for the dynamics is developed based on a number of fundamental principles and considerations, and a sy......In this paper, the dynamics of spontaneous shape fluctuations of a single, giant quasi-spherical vesicle formed from a single lipid species is revisited theoretically. A coherent physical theory for the dynamics is developed based on a number of fundamental principles and considerations...... of the phenomenological constants in a canonical continuum description of fluid lipid-bilayer membranes and shown the consequences of this new interpretation in terms of the characteristics of the dynamics of vesicle shape fluctuations. Moreover, we have used the systematic formulation of our theory as a framework...... against which we have discussed the previously existing theories and their discrepancies. Finally, we have made a systematic prediction about the system-dependent characteristics of the relaxation dynamics of shape fluctuations of quasi-spherical vesicles with a view of experimental studies...
The onset of dynamic stall revisited
Energy Technology Data Exchange (ETDEWEB)
Mulleners, Karen; Raffel, Markus [German Aerospace Center (DLR), Goettingen (Germany)
2012-03-15
Dynamic stall on a helicopter rotor blade comprises a series of complex aerodynamic phenomena in response to the unsteady change of the blade's angle of attack. It is accompanied by a lift overshoot and delayed massive flow separation with respect to static stall. The classical hallmark of the dynamic stall phenomenon is the dynamic stall vortex. The flow over an oscillating OA209 airfoil under dynamic stall conditions was investigated by means of unsteady surface pressure measurements and time-resolved particle image velocimetry. The characteristic features of the unsteady flow field were identified and analysed utilising different coherent structure identification methods. An Eulerian and a Lagrangian procedure were adopted to locate the axes of vortices and the edges of Lagrangian coherent structures, respectively; a proper orthogonal decomposition of the velocity field revealed the energetically dominant coherent flow patterns and their temporal evolution. Based on the complementary information obtained by these methods the dynamics and interaction of vortical structures were analysed within a single dynamic stall life cycle leading to a classification of the unsteady flow development into five successive stages: the attached flow stage; the stall development stage; stall onset; the stalled stage; and flow reattachment. The onset of dynamic stall was specified here based on a characteristic mode of the proper orthogonal decomposition of the velocity field. Variations in the flow field topology that accompany the stall onset were verified by the Lagrangian coherent structure analysis. The instantaneous effective unsteadiness was defined as a single representative parameter to describe the influence of the motion parameters. Dynamic stall onset was found to be promoted by increasing unsteadiness. The mechanism that results in the detachment of the dynamic stall vortex from the airfoil was identified as vortex-induced separation caused by strong viscous
Fundamental laws of relativistic classical dynamics revisited
International Nuclear Information System (INIS)
Blaquiere, Augustin
1977-01-01
By stating that a linear differential form, whose coefficients are the components of the momentum and the energy of a particle, has an antiderivative, the basic equations of the dynamics of points are obtained, in the relativistic case. From the point of view of optimization theory, a connection between our condition and the Bellman-Isaacs equation of dynamic programming is discussed, with a view to extending the theory to relativistic wave mechanics [fr
Revisiting Urban Dynamics through Social Urban Data
Directory of Open Access Journals (Sweden)
Achilleas Psyllidis
2016-11-01
The contribution of this doctoral thesis is the design and development of a framework of novel methods and tools that enables the fusion of heterogeneous multidimensional data for cities. The framework could foster planners, researchers, and policy makers to capitalize on the new possibilities given by emerging social urban data. Having a deep understanding of the spatiotemporal dynamics of cities and, especially of the activity and movement behavior of people, is expected to play a crucial role in addressing the challenges of rapid urbanization. Overall, the framework proposed by this research has potential to open avenues of quantitative explorations of urban dynamics, contributing to the development of a new science of cities.
Energy Technology Data Exchange (ETDEWEB)
Bareyre, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1968-06-01
Experimental results of pion-nucleon elastic scattering below 1.6 GeV (total cross sections, angular distributions of elastic scattering and recoil nucleon polarizations) have been described by a partial wave analysis. This analysis has been developed, one energy at a time, with a method of least squares fits. A single solution is extracted by continuity with energy of the different solutions. Resonating behaviour has been clearly established for several partial waves. In addition to these important effects some phase shifts show rapid variations with energy. Present experimental situation does not permit to say whether these variations are due to experimental biases or to physical effects. (author) [French] Les resultats experimentaux de la diffusion elastique meson {pi} - nucleon au-dessous de 1.6 GeV (sections efficaces totales, distributions angulaires de diffusion elastique et de polarisation du nucleon de recul) sont decrits a l'aide d'une analyse en ondes partielles. Cette analyse est developpee energie par energie au moyen d'une methode d'ajustement en moindres carres. Un critere empirique de continuite des solutions en fonction de l'energie a permis d'isoler une solution unique. Des resonances sont clairement etablies pour plusieurs ondes partielles, ainsi que certains petits effets moins caracteristiques. Pour ceux-ci, la situation experimentale presente ne permet pas d'affirmer s'ils sont dus a des effets physiques ou a des biais experimentaux. (auteur)
Chiral dynamics with (non)strange quarks
Kubis, Bastian; Meißner, Ulf-G.
2017-01-01
We review the results and achievements of the project B.3. Topics addressed include pion photoproduction off the proton and off deuterium, three-flavor chiral perturbation theory studies, chiral symmetry tests in Goldstone boson decays, the development of unitarized chiral perturbation theory to next-to-leading order, the two-pole structure of the Λ(1405), the dynamical generation of the lowest S11 resonances, the theory of hadronic atoms and its application to various systems, precision studies in light-meson decays based on dispersion theory, the Roy-Steiner analysis of pion-nucleon scattering, a high-precision extraction of the elusive pion-nucleon σ-term, and aspects of chiral dynamics in few-nucleon systems.
Dynamics of asymmetric kinetic Ising systems revisited
International Nuclear Information System (INIS)
Huang, Haiping; Kabashima, Yoshiyuki
2014-01-01
The dynamics of an asymmetric kinetic Ising model is studied. Two schemes for improving the existing mean-field description are proposed. In the first scheme, we derive the formulas for instantaneous magnetization, equal-time correlation, and time-delayed correlation, considering the correlation between different local fields. To derive the time-delayed correlation, we emphasize that the small-correlation assumption adopted in previous work (Mézard and Sakellariou, 2011 J. Stat. Mech. L07001) is in fact not required. To confirm the prediction efficiency of our method, we perform extensive simulations on single instances with either temporally constant external driving fields or sinusoidal external fields. In the second scheme, we develop an improved mean-field theory for instantaneous magnetization prediction utilizing the notion of the cavity system in conjunction with a perturbative expansion approach. Its efficiency is numerically confirmed by comparison with the existing mean-field theory when partially asymmetric couplings are present. (paper)
Dynamical Properties of Internal Shocks Revisited
Energy Technology Data Exchange (ETDEWEB)
Pe’er, Asaf; Long, Killian [Physics Department, University College Cork, Cork (Ireland); Casella, Piergiorgio [INAF, Osservatorio Astronomico di Roma, Via Frascati 33, I-00078 Monteporzio Catone (Italy)
2017-09-01
Internal shocks between propagating plasma shells, originally ejected at different times with different velocities, are believed to play a major role in dissipating the kinetic energy, thereby explaining the observed light curves and spectra in a large range of transient objects. Even if initially the colliding plasmas are cold, following the first collision, the plasma shells are substantially heated, implying that in a scenario of multiple collisions, most collisions take place between plasmas of non-zero temperatures. Here, we calculate the dynamical properties of plasmas resulting from a collision between arbitrarily hot plasma shells, moving at arbitrary speeds. We provide simple analytical expressions valid for both ultrarelativistic and Newtonian velocities for both hot and cold plasmas. We derive the minimum criteria required for the formation of the two-shock wave system, and show that in the relativistic limit, the minimum Lorentz factor is proportional to the square root of the ratio of the initial plasmas enthalpies. We provide basic scaling laws of synchrotron emission from both the forward and reverse-shock waves, and show how these can be used to deduce the properties of the colliding shells. Finally, we discuss the implications of these results in the study of several astronomical transients, such as X-ray binaries, radio-loud quasars, and gamma-ray bursts.
DEFF Research Database (Denmark)
Tegtmeier, Silke; Meyer, Verena; Pakura, Stefanie
2017-01-01
were captured when they described entrepreneurs. Therefore, this paper aims to revisit gender role stereotypes among young adults. Design/methodology/approach: To measure stereotyping, participants were asked to describe entrepreneurs in general and either women or men in general. The Schein......Purpose: Entrepreneurship is shaped by a male norm, which has been widely demonstrated in qualitative studies. The authors strive to complement these methods by a quantitative approach. First, gender role stereotypes were measured in entrepreneurship. Second, the explicit notions of participants......: The images of men and entrepreneurs show a high and significant congruence (r = 0.803), mostly in those adjectives that are untypical for men and entrepreneurs. The congruence of women and entrepreneurs was low (r = 0.152) and insignificant. Contrary to the participants’ beliefs, their explicit notions did...
Pion nucleon interaction at low energy
International Nuclear Information System (INIS)
Banerjee, M.K.
1979-03-01
A theory of the πN interaction at low energy is described. An analogy is made with an unusual approach to potential scattering theory. Phase shifts, cross sections, and scattering amplitudes and lengths are calculated. 28 references
Determination of backward pion nucleon scattering amplitudes
International Nuclear Information System (INIS)
Pietarinen, E.
1978-04-01
Backward C(sup(+-))πN amplitudes are determined from πN→Nπ and NantiN→2π differential cross sections in such a way that they are consistent with the analyticity properties and information of the unphysical ππ→NantiN amplitudes. Combining the result with forward C(sup(+-)) amplitudes positive and negative parity resonances are extracted. An error analysis of the amplitudes is performed. (author)
Sirmas, Nick; Radulescu, Matei I.
2016-01-01
The problem of thermal ignition in a homogeneous gas is revisited from a molecular dynamics perspective. A two-dimensional model is adopted, which assumes reactive disks of type A and B in a fixed area that react to form type C products if an activation threshold for impact is surpassed. Such a reaction liberates kinetic energy to the product particles, representative of the heat release. The results for the ignition delay are compared with those obtained from the continuum description assumi...
Revisiting r > g-The asymptotic dynamics of wealth inequality
Berman, Yonatan; Shapira, Yoash
2017-02-01
Studying the underlying mechanisms of wealth inequality dynamics is essential for its understanding and for policy aiming to regulate its level. We apply a heterogeneous non-interacting agent-based modeling approach, solved using iterated maps to model the dynamics of wealth inequality based on 3 parameters-the economic output growth rate g, the capital value change rate a and the personal savings rate s and show that for a income distribution. If a > g, the wealth distribution constantly becomes more and more inegalitarian. We also show that when a economic output, which also implies that the wealth-disposable income ratio asymptotically converges to s /(g - a) .
Quantum Critical Point revisited by the Dynamical Mean Field Theory
Xu, Wenhu; Kotliar, Gabriel; Tsvelik, Alexei
Dynamical mean field theory is used to study the quantum critical point (QCP) in the doped Hubbard model on a square lattice. The QCP is characterized by a universal scaling form of the self energy and a spin density wave instability at an incommensurate wave vector. The scaling form unifies the low energy kink and the high energy waterfall feature in the spectral function, while the spin dynamics includes both the critical incommensurate and high energy antiferromagnetic paramagnons. We use the frequency dependent four-point correlation function of spin operators to calculate the momentum dependent correction to the electron self energy. Our results reveal a substantial difference with the calculations based on the Spin-Fermion model which indicates that the frequency dependence of the the quasiparitcle-paramagnon vertices is an important factor. The authors are supported by Center for Computational Design of Functional Strongly Correlated Materials and Theoretical Spectroscopy under DOE Grant DE-FOA-0001276.
Quantum critical point revisited by dynamical mean-field theory
Xu, Wenhu; Kotliar, Gabriel; Tsvelik, Alexei M.
2017-03-01
Dynamical mean-field theory is used to study the quantum critical point (QCP) in the doped Hubbard model on a square lattice. The QCP is characterized by a universal scaling form of the self-energy and a spin density wave instability at an incommensurate wave vector. The scaling form unifies the low-energy kink and the high-energy waterfall feature in the spectral function, while the spin dynamics includes both the critical incommensurate and high-energy antiferromagnetic paramagnons. We use the frequency-dependent four-point correlation function of spin operators to calculate the momentum-dependent correction to the electron self-energy. By comparing with the calculations based on the spin-fermion model, our results indicate the frequency dependence of the quasiparticle-paramagnon vertices is an important factor to capture the momentum dependence in quasiparticle scattering.
Quantum critical point revisited by dynamical mean-field theory
International Nuclear Information System (INIS)
Xu, Wenhu; Kotliar, Gabriel; Rutgers University, Piscataway, NJ; Tsvelik, Alexei M.
2017-01-01
Dynamical mean-field theory is used to study the quantum critical point (QCP) in the doped Hubbard model on a square lattice. We characterize the QCP by a universal scaling form of the self-energy and a spin density wave instability at an incommensurate wave vector. The scaling form unifies the low-energy kink and the high-energy waterfall feature in the spectral function, while the spin dynamics includes both the critical incommensurate and high-energy antiferromagnetic paramagnons. Here, we use the frequency-dependent four-point correlation function of spin operators to calculate the momentum-dependent correction to the electron self-energy. Furthermore, by comparing with the calculations based on the spin-fermion model, our results indicate the frequency dependence of the quasiparticle-paramagnon vertices is an important factor to capture the momentum dependence in quasiparticle scattering.
The “anomalous” dynamics of decahyroisoquinoline revisited
Energy Technology Data Exchange (ETDEWEB)
Casalini, R.; Roland, C. M. [Chemistry Division, Naval Research Laboratory, Washington, DC 20375-5320 (United States)
2016-01-14
Decahydroisoquinoline (DHIQ) appears to be a unique material—the only non-associated, simple liquid with dynamics deviating from density scaling. To examine whether this anomaly is real, the density, ρ, of DHIQ was measured at temperatures, T, as low as 214 K and pressures up to ∼1.2 GPa. This enabled the equation of state (EoS) to be determined, without extrapolation, over the range of thermodynamic conditions for which the relaxation times had been reported. Using this less ambiguous EoS, we find that within the precision of the available relaxation times, the latter are a function of T/ρ{sup 3.9}, contrary to previous reports. Thus, the behavior of DHIQ is unexceptional; similar to every non-associated liquid tested to date, its dynamics comply with density scaling.
Dynamic and gated PET. Quantitative imaging of the heart revisited
International Nuclear Information System (INIS)
Nekolla, S.G.
2005-01-01
This short overview focuses on the basic implementation as well as applications of cardiac PET studies acquired in dynamic and ECG triggered modes. Both acquisition modes are well suited for quantitative analysis and the advantages of such an approach are discussed. An outlook on the measurement of respiratory triggered studies and the new challenges this data presents is provided. In the context of modern PET/CT tomographs with the combination of high sensitivity and morphologic resolution, the promise of list mode acquisition is investigated. The before mentioned acquisition modes are ideal candidates for this technology the utility of which in a clinical setting is briefly discussed. The retrospective generation of dynamic and gated image data (and any combinations) is greatly facilitated with this approach. Finally, a novel presentation mode for the wealth of quantitative information generated by these systems is presented. (orig.)
Diagnosing erectile dysfunction: the penile dynamic colour duplex ultrasound revisited.
Aversa, A; Bruzziches, R; Spera, G
2005-12-01
A number of disease processes of the penis including Peyronie's disease, priapism, penile fractures and tumors are clearly visualized with ultrasound. Diagnostic evaluation of erectile dysfunction (ED) by penile dynamic colour-duplex Doppler ultrasonography (D-CDDU) is actually considered a second level approach to ED patients because of the fact that intracavernous injections test IV with prostaglandin-E(1) may provide important information about the patients' erectile capacity. However, no direct vascular imaging and a high percentage of false negative diagnoses of vasculogenic ED are its major pitfalls and subsequent treatment decisions remain quite limited. The occurrence of ED and its sentinel relationship to cardiovascular disease has prompted more accurate vascular screening in all patients even in the absence of cardiovascular risk factors. The sonographic evaluation of the intima-media thickness of the carotid arteries may sometimes represent an early manifestation of diffuse atherosclerotic disease and endothelial damage. This latter finding is often the cause of failure to oral agents, i.e. phosphodiesterase inhibitors, because of inability of the dysfunctional endothelium to release nitric oxide. D-CDDU represents an accurate tool to investigate cavernous artery inflow and venous leakage when compared with more invasive diagnostic techniques i.e. selective arteriography and dynamic infusion cavernosometry along with cavernosography.
Geostationary secular dynamics revisited: application to high area-to-mass ratio objects
Gachet, Fabien; Celletti, Alessandra; Pucacco, Giuseppe; Efthymiopoulos, Christos
2017-06-01
The long-term dynamics of the geostationary Earth orbits (GEO) is revisited through the application of canonical perturbation theory. We consider a Hamiltonian model accounting for all major perturbations: geopotential at order and degree two, lunisolar perturbations with a realistic model for the Sun and Moon orbits, and solar radiation pressure. The long-term dynamics of the GEO region has been studied both numerically and analytically, in view of the relevance of such studies to the issue of space debris or to the disposal of GEO satellites. Past studies focused on the orbital evolution of objects around a nominal solution, hereafter called the forced equilibrium solution, which shows a particularly strong dependence on the area-to-mass ratio. Here, we (i) give theoretical estimates for the long-term behavior of such orbits, and (ii) we examine the nature of the forced equilibrium itself. In the lowest approximation, the forced equilibrium implies motion with a constant non-zero average `forced eccentricity', as well as a constant non-zero average inclination, otherwise known in satellite dynamics as the inclination of the invariant `Laplace plane'. Using a higher order normal form, we demonstrate that this equilibrium actually represents not a point in phase space, but a trajectory taking place on a lower-dimensional torus. We give analytical expressions for this special trajectory, and we compare our results to those found by numerical orbit propagation. We finally discuss the use of proper elements, i.e., approximate integrals of motion for the GEO orbits.
Nguyen, Nhan
2013-01-01
This paper presents the optimal control modification for linear uncertain plants. The Lyapunov analysis shows that the modification parameter has a limiting value depending on the nature of the uncertainty. The optimal control modification exhibits a linear asymptotic property that enables it to be analyzed in a linear time invariant framework for linear uncertain plants. The linear asymptotic property shows that the closed-loop plants in the limit possess a scaled input-output mapping. Using this property, we can derive an analytical closed-loop transfer function in the limit as the adaptive gain tends to infinity. The paper revisits the Rohrs counterexample problem that illustrates the nature of non-robustness of model-reference adaptive control in the presence of unmodeled dynamics. An analytical approach is developed to compute exactly the modification parameter for the optimal control modification that stabilizes the plant in the Rohrs counterexample. The linear asymptotic property is also used to address output feedback adaptive control for non-minimum phase plants with a relative degree 1.
Chiral symmetry and low energy pion-nucleon scattering
International Nuclear Information System (INIS)
Coon, S.A.
1999-01-01
In these lectures, I examine the effect of the meson factory πN data on the current algebra/PCAC program which describes chiral symmetry breaking in this system. After historical remarks on the current algebra/PCAC versus chiral Lagrangians approaches to chiral symmetry, and description of the need for πN amplitudes with virtual (off-mass-shell) pions in nuclear force models and other nuclear physics problems, I begin with kinematics and isospin aspects of the invariant amplitudes. A detailed introduction to the hadronic vector and axial-vector currents and the hypothesis of partially conserved axial-vector currents (PCAC) follows. I review and test against contemporary data the PCAC predictions of the Goldberger-Treiman relation, and the Adler consistency condition for a πN amplitude. Then comes a detailed description of the current algebra Ward-Takahashi identities in the chiral limit and a brief account of the on-shell current algebra Ward-Takahashi identities. The latter identities form the basis of so-called current algebra models of πN scattering. I then test these models against the contemporary empirical πN amplitudes extrapolated into the subthreshold region via dispersion relations. The scale and the t dependence of the 'sigma term' is determined by the recent data. (author)
Delta: the first pion nucleon resonance - its discovery and applications
International Nuclear Information System (INIS)
Nagle, D.E.
1984-07-01
It is attempted to recapture some of the fun and excitement of the pion-scattering work that led to the discovery of what is now called the delta particle. How significant this discovery was became apparent only gradually. That the delta is alive today and thriving at Los Alamos (as well as other places) is described
Pion-nucleon scattering in the Chiral bag model
International Nuclear Information System (INIS)
Israilov, Z.Z.; Musakhanov, M.M.
1981-01-01
The effective hamiltonian of the πNΔ-system in the framework of the Chiral Bag Model (CBM) contains πNN-, πNΔ-, πΔΔ-interaction terms with a form factor which is esstentially dependent on the size and shape of the quark bag. The interation of the Born graphs of this model provides successful description of the (3,3) and (3,1) phase shifts [in the (3,3) resonance region] where the values of the paramters agree with the CBM. (orig.)
Separable-potential model for the pion--nucleon interaction
International Nuclear Information System (INIS)
Nutt, W.T.
1976-01-01
A separable potential which fits the low and intermediate π-N scattering is proposed which is more convenient for application than those separable models which use Regge parameterizations of the very high energy phase shifts. The form factors for this model are equal to zero for momenta q greater than 1 GeV/c, and are expected to provide more reasonable off-shell behavior than the form factors obtained from those models based on the Regge extrapolation
Delta-nucleus dynamics: proceedings of symposium
International Nuclear Information System (INIS)
Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P.
1983-10-01
The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta Δ(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe Δ-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented
Delta-nucleus dynamics: proceedings of symposium
Energy Technology Data Exchange (ETDEWEB)
Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P. (eds.)
1983-10-01
The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta ..delta..(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe ..delta..-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented. (WHK)
Energy Technology Data Exchange (ETDEWEB)
Becher,
2002-08-08
After contrasting the low energy effective theory for the baryon sector with one for the Goldstone sector, I use the example of pion nucleon scattering to discuss some of the progress and open issues in baryon chiral perturbation theory.
Revisiting the body-schema concept in the context of whole-body postural-focal dynamics.
Morasso, Pietro; Casadio, Maura; Mohan, Vishwanathan; Rea, Francesco; Zenzeri, Jacopo
2015-01-01
The body-schema concept is revisited in the context of embodied cognition, further developing the theory formulated by Marc Jeannerod that the motor system is part of a simulation network related to action, whose function is not only to shape the motor system for preparing an action (either overt or covert) but also to provide the self with information on the feasibility and the meaning of potential actions. The proposed computational formulation is based on a dynamical system approach, which is linked to an extension of the equilibrium-point hypothesis, called Passive Motor Paradigm: this dynamical system generates goal-oriented, spatio-temporal, sensorimotor patterns, integrating a direct and inverse internal model in a multi-referential framework. The purpose of such computational model is to operate at the same time as a general synergy formation machinery for planning whole-body actions in humanoid robots and/or for predicting coordinated sensory-motor patterns in human movements. In order to illustrate the computational approach, the integration of simultaneous, even partially conflicting tasks will be analyzed in some detail with regard to postural-focal dynamics, which can be defined as the fusion of a focal task, namely reaching a target with the whole-body, and a postural task, namely maintaining overall stability.
Revisiting the Body-Schema Concept in the Context of Whole-Body Postural-Focal Dynamics
Morasso, Pietro; Casadio, Maura; Mohan, Vishwanathan; Rea, Francesco; Zenzeri, Jacopo
2015-01-01
The body-schema concept is revisited in the context of embodied cognition, further developing the theory formulated by Marc Jeannerod that the motor system is part of a simulation network related to action, whose function is not only to shape the motor system for preparing an action (either overt or covert) but also to provide the self with information on the feasibility and the meaning of potential actions. The proposed computational formulation is based on a dynamical system approach, which is linked to an extension of the equilibrium-point hypothesis, called Passive Motor Paradigm: this dynamical system generates goal-oriented, spatio-temporal, sensorimotor patterns, integrating a direct and inverse internal model in a multi-referential framework. The purpose of such computational model is to operate at the same time as a general synergy formation machinery for planning whole-body actions in humanoid robots and/or for predicting coordinated sensory–motor patterns in human movements. In order to illustrate the computational approach, the integration of simultaneous, even partially conflicting tasks will be analyzed in some detail with regard to postural-focal dynamics, which can be defined as the fusion of a focal task, namely reaching a target with the whole-body, and a postural task, namely maintaining overall stability. PMID:25741274
Revisiting the body-schema concept in the context of Whole-Body Postural-Focal Dynamics
Directory of Open Access Journals (Sweden)
Pietro eMorasso
2015-02-01
Full Text Available The body schema concept is revisited in the context of embodied cognition, further developing the theory formulated by Marc Jeannerod that the motor system is part of a simulation network related to action, whose function is not only to shape the motor system for preparing an action (either overt or covert, but also to provide the self with information on the feasibility and the meaning of potential actions. The proposed computational formulation is based on a dynamical system approach, which is linked to an extension of the Equilibrium Point Hypothesis, called Passive Motor Paradigm: this dynamical system generates goal-oriented, spatio-temporal, sensorimotor patterns, integrating a direct and inverse internal model in a multi-referential framework. The purpose of such computational model is to operate at the same time as a general synergy formation machinery for planning whole-body actions in humanoid robots and/or for predicting coordinated sensory-motor patterns in human movements. In order to illustrate the computational approach, the integration of simultaneous, even partially conflicting tasks will be analyzed in some detail with regard to postural-focal dynamics, which can be defined as the fusion of a focal task, namely reaching a target with the whole-body, and a postural task, namely maintaining overall stability.
International Nuclear Information System (INIS)
Li, Yuanjing
2015-01-01
This paper revisits the short-term price and volatility dynamics in day-ahead electricity markets in consideration of an increasing share of wind power, using an example of the Nord Pool day-ahead market and the Danish wind generation. To do so, a GARCH process is applied, and market coupling and the counterbalance effect of hydropower in the Scandinavian countries are additionally accounted for. As results, we found that wind generation weakly dampens spot prices with an elasticity of 0.008 and also reduces price volatility with an elasticity of 0.02 in the Nordic day-ahead market. The results shed lights on the importance of market coupling and interactions between wind power and hydropower in the Nordic system through cross-border exchanges, which play an essential role in price stabilization. Additionally, an EGARCH specification confirms an asymmetric influence of the price innovations, whereby negative shocks produce larger volatility in the Nordic spot market. While considering heavy tails in error distributions can improve model fits significantly, the EGARCH model outperforms the GARCH model on forecast evaluations. (author)
Co-design revisited: exploring problematic co-design dynamics in kids
Van Mechelen, Maarten; Zaman, Bieke; Vanden Abeele, Vero; Laenen, Ann
2013-01-01
This paper explores problematic co-design dynamics in children, which are defined as a system of intragroup dynamics occurring within a group of at random or purposefully selected children sharing a common design goal. These dynamics impact children’s development of creative solutions in co-design, but have rarely been addressed in literature. Therefore, we set out a multiple case study with 9- to 10-year olds in three elementary schools. Although not an exhaustive lis...
Directory of Open Access Journals (Sweden)
Panduranga Prashanth
2010-01-01
Full Text Available It is known that a dynamic left ventricular outflow tract (LVOT obstruction exists in patients, following aortic valve replacement (AVR and is usually considered to be benign. We present a patient with dynamic LVOT obstruction following AVR, who developed refractory cardiogenic shock and expired inspite of various treatment strategies. This phenomenon must be diagnosed early and should be considered as a serious and potentially fatal complication following AVR. The possible mechanisms and treatment options are reviewed.
Chemical Kinetics, Heat Transfer, and Sensor Dynamics Revisited in a Simple Experiment
Sad, Maria E.; Sad, Mario R.; Castro, Alberto A.; Garetto, Teresita F.
2008-01-01
A simple experiment about thermal effects in chemical reactors is described, which can be used to illustrate chemical reactor models, the determination and validation of their parameters, and some simple principles of heat transfer and sensor dynamics. It is based in the exothermic reaction between aqueous solutions of sodium thiosulfate and…
The service quality-satisfaction link revisited : exploring asymetries and dynamics
Falk, T.; Hammerschmidt, M.; Schepers, J.J.L.
2010-01-01
This study provides deeper insight in the link between service quality and customer satisfaction. The traditional assumption of a linear relationship is challenged by exploring asymmetries and dynamics. The simultaneous influence of service quality and customer experience on satisfaction is examined
The auditory dynamic attending theory revisited: A closer look at the pitch comparison task.
Bauer, Anna-Katharina R; Jaeger, Manuela; Thorne, Jeremy D; Bendixen, Alexandra; Debener, Stefan
2015-11-11
The dynamic attending theory as originally proposed by Jones, 1976. Psychol. Rev. 83(5), 323-355 posits that tone sequences presented at a regular rhythm entrain attentional oscillations and thereby facilitate the processing of sounds presented in phase with this rhythm. The increased interest in neural correlates of dynamic attending requires robust behavioral indicators of the phenomenon. Here we aimed to replicate and complement the most prominent experimental implementation of dynamic attending (Jones et al., 2002. Psychol. Sci. 13(4), 313-319). The paradigm uses a pitch comparison task in which two tones, the initial and the last of a longer series, have to be compared. In-between the two, distractor tones with variable pitch are presented, at a regular pace. A comparison tone presented in phase with the entrained rhythm is hypothesized to lead to better behavioral performance. Aiming for a conceptual replication, four different variations of the original paradigm were created which were followed by an exact replication attempt. Across all five experiments, only 40 of the 140 tested participants showed the hypothesized pattern of an inverted U-shaped profile in task accuracy, and the group average effects did not replicate the pattern reported by Jones et al., 2002. Psychol. Sci. 13(4), 313-319 in any of the five experiments. However, clear evidence for a relationship between musicality and overall behavioral performance was found. This study casts doubt on the suitability of the pitch comparison task for demonstrating auditory dynamic attending. We discuss alternative tasks that have been shown to support dynamic attending theory, thus lending themselves more readily to studying its neural correlates. This article is part of a Special Issue entitled SI: Prediction and Attention. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.
Nonreactive spreading at high-temperature revisited for metal systems via molecular dynamics.
Benhassine, M; Saiz, E; Tomsia, A P; De Coninck, J
2009-10-06
The spreading for Cu and Ag droplets on top of a rigid solid surface modeling Mo is herewith considered via molecular dynamics. The dynamics of the base radius and the contact angle are recorded and fitted using the molecular-kinetic theory. A method is described to determine for liquid metals at the microscopic level the parameters appearing in this theory. These microscopic parameters are calculated directly in the simulations and compared to the fitted values. The agreement between the fitted values and the calculated ones shows that the dissipation of energy within the drop is caused primarily by the friction of liquid atoms over the substrate. This validation supports the understanding of the mechanisms controlling the spreading of liquid metals which, up to now, were based on experimental data and fitting procedures.
The general dynamic model of island biogeography revisited on the level of major plant families
DEFF Research Database (Denmark)
Lenzner, Bernd; Beierkuhnlein, Carl; Patrick, Weigelt
2017-01-01
Aim: The general dynamic model (GDM) proposed by Whittaker et al. (2008) is a widely accepted theoretical framework in island biogeography. In this study, we explore whether GDM predictions hold when overall plant diversity is deconstructed into major plant families. Location: 101 islands from 14...... oceanic archipelagos worldwide. Methods: Occurrence data for all species of nine large, cosmopolitan flowering plant families were used to test predictions derived from the GDM. We analyzed the effects of island area and age on species richness as well as number and percentage of single-island endemic...... species per family using mixed-effect models. Results: Total species and endemic richness as well as the percentage of endemic species showed a hump-shaped relationship with island age. The overall pattern was mainly driven by few species-rich plant families. Varying patterns were found for individual...
Dispositional envy revisited: unraveling the motivational dynamics of benign and malicious envy.
Lange, Jens; Crusius, Jan
2015-02-01
Previous research has conceptualized dispositional envy as a unitary construct. Recently however, episodic envy has been shown to emerge in two qualitatively different forms. Benign envy is related to the motivation to move upward, whereas malicious envy is related to pulling superior others down. In four studies (N = 1,094)--using the newly developed Benign and Malicious Envy Scale (BeMaS)--we show that dispositional envy is also characterized by two independent dimensions related to distinct motivational dynamics and behavioral consequences. Dispositional benign and malicious envy uniquely predict envious responding following upward social comparisons. Furthermore, they are differentially connected to hope for success and fear of failure. Corresponding to these links, dispositional benign envy predicted faster race performance of marathon runners mediated via higher goal setting. In contrast, dispositional malicious envy predicted race goal disengagement. The findings highlight that disentangling the two sides of envy opens up numerous research avenues. © 2014 by the Society for Personality and Social Psychology, Inc.
Revisiting Gill's Circulation. Dynamic Response to Diabatic Heating of Different Horizontal Extents
Reboredo, B.; Bellon, G.
2017-12-01
The horizontal extent of diabatic heating associated with the MJO is thought to be crucial to its development, and the inability of GCMs to simulate the spatial, horizontal organization of clouds is considered a leading hypothesis to explain their limited capacity to simulate MJO events. This prevents the MJO large-circulation response from developing and feeding back on the development of clouds. We apply mid-tropospheric heating of different size in simple linear and non-linear models of the tropical atmosphere following Gill's seminal work on heat-induced tropical circulations. Results show that there is a scale for which the characteristic circulation {Γ c} for the vertical advection of moisture to produce the latent heat mean {Q} gives a rough estimate of the real world MJO scale. Overturning circulation flow rates above {Γ c} account for a circulation that transports more moisture than necessary to be maintained, and below {Γ c}, circulation would not transport enough moisture to maintain circulation. This dynamic scale might constrain the size of the spatially-organised convection necessary to the development of an MJO event. However, other effects are expected to modulate this scale, such as vertical advection of moisture anomalies, horizontal advection, evaporation, radiative heating, and sensible heat fluxes.
International Nuclear Information System (INIS)
Tasali, N.; Cubuk, R.; Aricak, M.; Ozarar, M.; Saydam, B.; Nur, H.; Tuncbilek, N.
2012-01-01
Purpose: We aimed to assess the contrast enhancement patterns of the retrodiscal tissue with dynamic contrast-enhanced MR imaging (DCE-MRI) with respect to different temporomandibular joint disc pathologies. Additionally, we questioned the relationship between the temporomandibular joint (TMJ) pain and the contrast enhancement pattern of the retrodiscal tissue regardless of the TMJ disc position. Materials and methods: 52 joints of 26 patients (4 males and 22 females) who have pain in at least at one of their TMJ were included in this study. For the qualitative analysis, the joints were divided into four groups in terms of their disc positions: normal (1), partially displaced with or without reduction (2), totally dislocated with reduction (3) and totally dislocated without reduction (4). Besides, two different joint groups were constituted, namely the painful group and painless group according to the clinical findings without taking the TMJ disc positions into account. Quantitative analyses were made by means of measuring signal intensity ratios (SI) ratio at the retrodiscal tissue (from internal side and external side of the each joint) using DCE-MRI and these measurements were analyzed with paired samples t test to define the difference between the measurements. At the second stage, the time-dependent arithmetical mean values of the SI ratios were calculated for each joint group and significant differences between the groups were questioned using analysis of variance (ANOVA) test. Besides, painful and painless groups which were classified on the basis of the clinical data were compared according to the mean SI ratios found for each joint and the significant differences between these two groups were assessed by means of Student's T test. The results were assessed in 95% confidence interval where the significance level was p < 0.05. Results: A significant difference was observed between the internal and external contrast enhancement of the joints with partial
Euclidean Dynamical Triangulation revisited: is the phase transition really 1st order?
International Nuclear Information System (INIS)
Rindlisbacher, Tobias; Forcrand, Philippe de
2015-01-01
The transition between the two phases of 4D Euclidean Dynamical Triangulation (http://dx.doi.org/10.1016/0370-2693(92)90709-D) was long believed to be of second order until in 1996 first order behavior was found for sufficiently large systems (http://dx.doi.org/10.1016/0550-3213(96)00214-3, http://dx.doi.org/10.1016/S0370-2693(96)01277-4). However, one may wonder if this finding was affected by the numerical methods used: to control volume fluctuations, in both studies (http://dx.doi.org/10.1016/0550-3213(96)00214-3, http://dx.doi.org/10.1016/S0370-2693(96)01277-4) an artificial harmonic potential was added to the action and in (http://dx.doi.org/10.1016/S0370-2693(96)01277-4) measurements were taken after a fixed number of accepted instead of attempted moves which introduces an additional error. Finally the simulations suffer from strong critical slowing down which may have been underestimated. In the present work, we address the above weaknesses: we allow the volume to fluctuate freely within a fixed interval; we take measurements after a fixed number of attempted moves; and we overcome critical slowing down by using an optimized parallel tempering algorithm (http://dx.doi.org/10.1088/1742-5468/2010/01/P01020). With these improved methods, on systems of size up to N_4=64k 4-simplices, we confirm that the phase transition is 1"s"t order. In addition, we discuss a local criterion to decide whether parts of a triangulation are in the elongated or crumpled state and describe a new correspondence between EDT and the balls in boxes model. The latter gives rise to a modified partition function with an additional, third coupling. Finally, we propose and motivate a class of modified path-integral measures that might remove the metastability of the Markov chain and turn the phase transition into 2"n"d order.
Barunik, Jozef; Barunikova, Michaela
2015-01-01
This paper revisits the fractional co-integrating relationship between ex-ante implied volatility and ex-post realized volatility. Previous studies on stock index options have found biases and inefficiencies in implied volatility as a forecast of future volatility. It is argued that the concept of corridor implied volatility (CIV) should be used instead of the popular model-free option-implied volatility (MFIV) when assessing the relation as the latter may introduce bias to the estimation. In...
Court, Deborah
1999-01-01
Revisits and reviews Imre Lakatos' ideas on "Falsification and the Methodology of Scientific Research Programmes." Suggests that Lakatos' framework offers an insightful way of looking at the relationship between theory and research that is relevant not only for evaluating research programs in theoretical physics, but in the social…
Hadron dynamics at high energies
International Nuclear Information System (INIS)
Storrow, J.K.
1977-01-01
The nine lectures give a very brief introduction to hadron dynamics at high energies. They concentrate on basic concepts such as Regge poles, duality and geometrical ideas, and simple applications of these ideas to the problem of understanding data. To some extent two body phenomenology is emphasized at the expense of multiparticle final states and when the latter have been considered they have concentrated on inclusive reactions. One lecture discussed data on 2-2 reactions in order to provide the motivation for Regge pole theory, then two lectures are devoted to basic concepts. Then duality is introduced and shown to provide reasonable restrictions on a pole model. A lecture is then devoted to discussing geometrical ideas i.e. the t-dependence of data is looked at from an s-channel point of view. The section on two-body phenomenology is then concluded by discussing applications of the above ideas to two reactions-pion-nucleon scattering and np charge exchange scattering. The remaining three lectures are devoted to multiparticle reactions. Exclusive reactions are considered briefly and then the remainder of the course is concerned with inclusive reactions. The concepts of scaling and limiting fragmentation are discussed and Mueller's generalised optical theorem introduced and then applied in various kinematic limits. (author)
Pion scattering and nuclear dynamics
International Nuclear Information System (INIS)
Johnson, M.B.
1988-01-01
A phenomenological optical-model analysis of pion elastic scattering and single- and double-charge-exchange scattering to isobaric-analog states is reviewed. Interpretation of the optical-model parameters is briefly discussed, and several applications and extensions are considered. The applications include the study of various nuclear properties, including neutron deformation and surface-fluctuation contributions to the density. One promising extension for the near future would be to develop a microscopic approach based on powerful momentum-space methods brought to existence over the last decade. In this, the lowest-order optical potential as well as specific higher-order pieces would be worked out in terms of microscopic pion-nucleon and delta-nucleon interactions that can be determined within modern meson-theoretical frameworks. A second extension, of a more phenomenological nature, would use coupled-channel methods and shell-model wave functions to study dynamical nuclear correlations in pion double charge exchange. 35 refs., 11 figs., 1 tab
International Nuclear Information System (INIS)
Deau, Estelle
2007-12-01
In the Solar system, the planetary rings represent a fantastic opportunity of studying a majority of phenomena taking place in the thin discs. One can find discs at all redshifts and on all scales of the Universe. Planetary discs are very different: among the Jovian rings, one finds a halo of fine and diffuse dust; the rings of Uranus are very compact, like radially confined strings and the system of rings of Neptune consists of azimuthally stable arcs. However our interest goes on Saturn which has the most complex and widest system of rings known to date: 484 000 km and a vertical extension which increases with the distance to Saturn (typically less than 1 km to 10 000 km). The interest of such a matter organization around Saturn plus its many moons (more than one forty including 8 of a size of several hundreds kilometers) gave birth to the exploration mission CASSINI, supposed to allow the development and the refinement of models set up at the flybies of the two interplanetary probes VOYAGER. The CASSINI Mission began its nominal tour on January, 15 2005 after the orbital insertion the 1 July 2004 and the dropping of HUYGENS probe on january, 14 2005 on Titan's surface. The purpose of this thesis consists to revisit two subjects unsolved of long date in the photometric and dynamic behaviours of the Saturn's rings. In a first part, we try to solve the problem of accretion of matter within the Roche limit by studying the F ring. This ring, since its discovery in 1979 by Pioneer 11, is involved in a most various dynamic theories to explain its complex multi-radial structure and its variable azimuthal structure. We showed that the multi-radial structure of this ring can be understood by the existence of a spiral which is rolled up around a central area, bright, eccentric and inclined: the core. The lifespan of this spiral is not the same one as the core, suggesting that the processes which create the spiral are periodic. Moreover, we showed that the structure of the
DEFF Research Database (Denmark)
Holt, Robin; Cornelissen, Joep
2014-01-01
We critique and extend theory on organizational sensemaking around three themes. First, we investigate sense arising non-productively and so beyond any instrumental relationship with things; second, we consider how sense is experienced through mood as well as our cognitive skills of manipulation ...... research by revisiting Weick’s seminal reading of Norman Maclean’s book surrounding the tragic events of a 1949 forest fire at Mann Gulch, USA....
Pion-nucleon interaction and mesonic atoms. Progress report, 1 February 1978--31 January 1979
International Nuclear Information System (INIS)
Rebka, G.A. Jr.; Kunselman, R.
1979-01-01
During the year February 1, 1978 to January 31, 1979, the major activities under Task A were completion of the analysis of data taken in Experiment number 99, measurement of the cross section for completion of new π - p→π - π + n, apparatus and software for Experiment number 337, measurement of the cross section for π - p→π - π + n at 200 and 229 MeV, taking data for Experiment number 337, continued preparation for Experiment number 309, and double charge exchange in the disintegration of 16 O, 40 Ca and 208 Pb, consideration of a possible collaboration for detection of protons from μ - capture on nuclei and initiation of an association with physicists at Bates on measurements of (e,e'). The completed analysis of Experiment number 99 has left previous conclusions, that the integrated reaction cross section at the lowest energy is twice that interpolated from early measurements, intact. Experiment number 337 was mounted and the preliminary results for the reaction cross section at 229 MeV agree well with Experiment number 99. The more sophisticated instrumentation used in the latest measurements builds confidence in the validity of these results. An experiment on double charge exchange is being prepared and one on μ - capture is being considered. A graduate student from the University of Wyoming has begun thesis research at Bates
How well can the Chew-Low theory reproduce pion-nucleon scattering
International Nuclear Information System (INIS)
Bajaj, K.K.; Nogami, Y.
1975-01-01
When the Chew-Low theory for the πN interaction is used as a basis for studying the π-nucleus interaction, it is required to fit the free πN scattering data well. In this respect many calculations so far done are unsatisfactory. We show that an excellent fit is obtained within the existing Chew-Low framework if the inelasticity together with recoil and the crossing term are taken into account, and we comment on a recent work by Dover et al
Low equation, pion-nucleon scattering, and Castillejo-Dalitz-Dyson pole
International Nuclear Information System (INIS)
Nakano, K.; Nogami, Y.
1986-01-01
We examine the p-wave πN scattering at medium energies by means of the Low equation with a view to determining the form factor of the πN interaction. Solutions of the equation with and without a Castillejo-Dalitz-Dyson (CDD) pole are used. The solution with no CDD pole corresponds to the old Chew-Low model, whereas the one with a CDD pole corresponds to the quark version of the Chew-Low model. The πN interaction form factor is determined so that the Δ resonance is well reproduced. We find that the solution with a CDD pole leads to a softer form factor but is not as soft as those expected from the nucleon size in the quark model. Using the solutions and form factors thus determined, we also examine the pionic contributions to the nucleon magnetic moment and the nucleon mass
Pion-nucleon charge-exchange polarization by Gribov Reggeon calculus and the derivative rule
International Nuclear Information System (INIS)
Ardill, R.W.B.; Koehler, P.; Moriarty, K.J.M.
1977-01-01
The phenomenological consequences of the Gribov Reggeon calculus for the reaction πsup(-)+p→πdeg+n at 6 GeV/c are investigated and the polarization is obtained. The derivative rules is used to calculate the helicity flip amplitude. The results are very encouraging and would seem to indicate that the Gribov Reggeon calculus can be considered a more satisfactory approach to two-body phenomenology than the absorption model
Pionic atoms, the relativistic mean-field theory and the pion-nucleon scattering lenghts
International Nuclear Information System (INIS)
Goudsmit, P.F.A.; Leisi, H.J.; Matsinos, E.
1991-01-01
Analysing pionic-atom data of isoscalar nuclei within the relativistic mean-field (RMF) theory, we determine the pseudoscalar πNN mixing parameter x=0.24±0.06 (syst.) and the strength of the nuclear scalar meson field for pions, S π =-34±14 (syst.) MeV. We show that these values are compatible with the elementary π-N interaction. Our RMF model provides a solution to the long-standing problem of the s-wave repulsion. (orig.)
Elastic pion-nucleon P-wave scattering in soliton models
International Nuclear Information System (INIS)
Holzwarth, G.
1990-01-01
The equivalence of low-energy P-wave πN scattering in soliton models with the well-established Δ-isobar model is shown to hold even if all constraints on redundant collective variables are ignored. This provides strong support for the unusual (time-derivative) form of meson-baryon coupling in such models, and for the expectation that the soliton description of πN-scattering can be reliably extended down to pion threshold energies in a technically simple way. (orig.)
Pion-nucleon scattering in P11 channel and the Roper resonance
International Nuclear Information System (INIS)
Bugaev, K.A.; Yang, Shin Nan; Lee, T.S.H.
1996-01-01
The πN scattering in P 11 channel is investigated within the two-channel model of Pearce and Afnan. The model consists of: (1) vertex interactions b → πN, π∇ with b denoting either a bare nucleon or a bare Roper state, (2) a background potential υ πB,πB with B = N,∇. Assuming that υ πB,πB can be phenomenologically parameterized as a separable form and the πN inelasticity can be accounted for by dressing the ∇ in the π∇ channel by a ∇ ↔ πN vertex, it is found that the fit to the P 11 phase shifts up to 1 GeV favors a large mass of the bare Roper state. Our results are consistent with the findings of Pearce and Afnan that if the mass of the bare Roper state is restricted to be ≤1600 MeV, then a physical Roper will have a width which is too narrow causing a rapid variation of the phase shifts at energies near the resonance energy
The pion-nucleon scattering lengths from pionic hydrogen and deuterium
Energy Technology Data Exchange (ETDEWEB)
Schroeder, H.-C.; Badertscher, A.; Goudsmit, P.F.A.; Janousch, M.; Leisi, H.J.; Matsinos, E.; Sigg, D.; Zhao, Z.G. [ETH Zurich, Inst. for Particle Physics, Zurich (Switzerland); Chatellard, D.; Egger, J.P. [Neuchatel Univ. (Switzerland). Inst. de Physique; Gabathuler, K.; Hauser, P.; Simons, L.M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Rusi El Hassani, A.J. [Dept. de Physique, Faculte des Sciences et Technique, Tanger (Morocco)
2001-07-01
This is the final publication of the ETH Zurich-Neuchatel-PSI collaboration on the pionic hydrogen and deuterium precision X-ray experiments. We describe the recent hydrogen 3p-1s measurement, report on the determination of the Doppler effect correction to the transition line width, analyze the deuterium shift measurement and discuss implications of the combined hydrogen and deuterium results. From the pionic hydrogen 3p-1s transition experiments we obtain the strong-interaction energy level shift {epsilon}{sub 1s} = -7.108{+-}0.013 (stat.){+-}0.034 (syst.) eV and the total decay width {gamma}{sub 1s} = 0.868{+-}0.040 (stat.){+-}0.038 (syst.) eV of the 1s state. Taking into account the electromagnetic corrections we find the hadronic {pi}N s-wave scattering amplitude a{sub {pi}{sup -}p{yields}{pi}{sup -}p} = 0.0883{+-}0.0008 m{sub {pi}}{sup -1} for elastic scattering and a{sub {pi}{sup -}p{yields}{pi}{sup 0}n} = -0.128{+-}0.006 m{sub {pi}} {sup -1} for single charge exchange, respectively. We then combine the pionic hydrogen results with the 1s level shift measurement on pionic deuterium and test isospin symmetry of the strong interaction: our data are still compatible with isospin symmetry. The isoscalar and isovector {pi}N scattering lengths (within the framework of isospin symmetry) are found to be b{sub 0} = -0.0001{sup +0.0009}{sub -0.0021} m{sub {pi}}{sup -1} and b{sub 1} = -0.0885{sup +0.0010}{sub -0.0021} m{sub {pi}} {sup -1}, respectively. Using the GMO sum rule, we obtain from b{sub 1} a new value of the {pi}N coupling constant (g{sub {pi}}{sub N} = 13.21{sub -0.05}{sup +0.11}) from which follows the Goldberger-Treiman discrepancy {delta}{sub GT}=0.027{sub -0.008}{sup +0.012}. The new values of b{sub 0} and g{sub {pi}}{sub N} imply an increase of the nucleon sigma term by at least 9 MeV. (orig.)
Pion-nucleon vertex function with an off-shell nucleon
International Nuclear Information System (INIS)
Nutt, W.T.; Shakin, C.M.
1977-01-01
A model calculation for the π-N vertex function is presented in the case in which there is a single off-mass-shell nucleon and a (nearly) on-mass-shell pion. Very strong effects due to the P 11 resonance at 1470 MeV are found. A simple parametrization of the vertex function is prvided in the case that at least one nucleon is on its mass shell. (Auth.)
Logistics Innovation Process Revisited
DEFF Research Database (Denmark)
Gammelgaard, Britta; Su, Shong-Iee Ivan; Yang, Su-Lan
2011-01-01
Purpose – The purpose of this paper is to learn more about logistics innovation processes and their implications for the focal organization as well as the supply chain, especially suppliers. Design/methodology/approach – The empirical basis of the study is a longitudinal action research project...... that was triggered by the practical needs of new ways of handling material flows of a hospital. This approach made it possible to revisit theory on logistics innovation process. Findings – Apart from the tangible benefits reported to the case hospital, five findings can be extracted from this study: the logistics...... innovation process model may include not just customers but also suppliers; logistics innovation in buyer-supplier relations may serve as an alternative to outsourcing; logistics innovation processes are dynamic and may improve supplier partnerships; logistics innovations in the supply chain are as dependent...
Sea quark contribution to the dynamical mass and light quark content of a nucleon
International Nuclear Information System (INIS)
Singh, J.P.
1995-01-01
We calculate the flavor mixing in the wave function of a light valence quark. For this, we use the idea of dynamical symmetry breaking. A sea quark of a different flavor may appear through the vacuum polarization of a gluon propagator which appears in the gap equation for the dynamical mass. We have also used the fact that any one of these quark lines may undergo condensation. The dependence of the dynamical mass, generated in this way, on the sea quark mass up to quadratic terms has been retained. The momentum dependence is like 1/p 4 , in contrast with the 1/p 2 kind of dependence which occurs for the leading term of the dynamical mass in the subasymptotic region. The extension of the result to the ''mass shell'' yields σ πN =53--54 MeV for the pion-nucleon σ term and m s left-angle p|bar ss|p right-angle=122--264 meV for the strange quark contribution to the proton mass, for different values of parameters. These are in reasonable agreement with current phenomenological estimates of these quantities
Nuclear chiral dynamics and thermodynamics
Holt, Jeremy W.; Kaiser, Norbert; Weise, Wolfram
2013-11-01
This presentation reviews an approach to nuclear many-body systems based on the spontaneously broken chiral symmetry of low-energy QCD. In the low-energy limit, for energies and momenta small compared to a characteristic symmetry breaking scale of order 1 GeV, QCD is realized as an effective field theory of Goldstone bosons (pions) coupled to heavy fermionic sources (nucleons). Nuclear forces at long and intermediate distance scales result from a systematic hierarchy of one- and two-pion exchange processes in combination with Pauli blocking effects in the nuclear medium. Short distance dynamics, not resolved at the wavelengths corresponding to typical nuclear Fermi momenta, are introduced as contact interactions between nucleons. Apart from a set of low-energy constants associated with these contact terms, the parameters of this theory are entirely determined by pion properties and low-energy pion-nucleon scattering observables. This framework (in-medium chiral perturbation theory) can provide a realistic description of both isospin-symmetric nuclear matter and neutron matter, with emphasis on the isospin-dependence determined by the underlying chiral NN interaction. The importance of three-body forces is emphasized, and the role of explicit Δ(1232)-isobar degrees of freedom is investigated in detail. Nuclear chiral thermodynamics is developed and a calculation of the nuclear phase diagram is performed. This includes a successful description of the first-order phase transition from a nuclear Fermi liquid to an interacting Fermi gas and the coexistence of these phases below a critical temperature Tc. Density functional methods for finite nuclei based on this approach are also discussed. Effective interactions, their density dependence and connections to Landau Fermi liquid theory are outlined. Finally, the density and temperature dependences of the chiral (quark) condensate are investigated.
Neumann, Jan; Golub, Benjamin; Odebrecht, Lisa-Marie; Ludwig, Ralf; Paschek, Dietmar
2018-05-01
We study ionic liquids composed of 1-alkyl-3-methylimidazolium cations and bis(trifluoromethyl-sulfonyl)imide anions ([CnMIm][NTf2]) with varying chain-length n = 2, 4, 6, 8 by using molecular dynamics simulations. We show that a reparametrization of the dihedral potentials as well as charges of the [NTf2] anion leads to an improvement of the force field model introduced by Köddermann, Paschek, and Ludwig [ChemPhysChem 8, 2464 (2007)] (KPL-force field). A crucial advantage of the new parameter set is that the minimum energy conformations of the anion (trans and gauche), as deduced from ab initio calculations and Raman experiments, are now both well represented by our model. In addition, the results for [CnMIm][NTf2] show that this modification leads to an even better agreement between experiment and molecular dynamics simulation as demonstrated for densities, diffusion coefficients, vaporization enthalpies, reorientational correlation times, and viscosities. Even though we focused on a better representation of the anion conformation, also the alkyl chain-length dependence of the cation behaves closer to the experiment. We strongly encourage to use the new NGOLP (Neumann, Golub, Odebrecht, Ludwig, Paschek) force field for the [NTf2] anion instead of the earlier KPL parameter set for computer simulations aiming to describe the thermodynamics, dynamics, and also structure of imidazolium-based ionic liquids.
Psyllidis, A.
2016-01-01
The study of dynamic spatial and social phenomena in cities has evolved rapidly in the recent years, yielding new insights into urban dynamics. This evolution is strongly related to the emergence of new sources of data for cities (e.g. sensors, mobile phones, online social media etc.), which have
Directory of Open Access Journals (Sweden)
Dörr A.J.M.
2013-06-01
Full Text Available Understanding population dynamics and regulation is fundamental for predicting establishment and spread of invasive alien species. In addition, the population biology of invasive alien species offers an opportunity to study basic ecological processes. In this context, we investigated reproductive and growth plasticity in the invasive crayfish Procambarus clarkii in Lake Trasimeno (central Italy. In total, 3153 crayfish were collected monthly from June 2007 to July 2009. The molt status was assessed by evaluating the exoskeleton hardness. To assess the reproductive cycle, the gonado-somatic and wet hepato-somatic indices were calculated for females. The reproductive status of males was appraised as well. We estimated growth and longevity using the von Bertalanffy growth function, and calculated the total, natural and fishing mortality indices. We then compared our present data with those obtained from the same population eight years before. Our results indicate some changes in population dynamics and in both molting and reproductive periods since the initial invasion of the shallow lake investigated. Long-term differences in the life history of the Trasimeno population may be the result of selective pressures different from those of the native range, but may also result from colonization events and human interference caused by professional fishing activities.
International Nuclear Information System (INIS)
Hancevic, Pedro Ignacio
2017-01-01
The Acid Rain Program (ARP) was implemented in 1995. Since then, coal-fired boilers have had to choose among three main compliance alternatives: purchase pollution permits; switch to an alternative lower-sulfur coal; or adopt a scrubber. This decision problem is driven by the evolution of several economic variables and is revised when significant changes (to prices, quality of inputs, output level, technology, transport costs, regulations, among others) occur. Using a structural dynamic discrete choice model, I recover cost parameters and use them to evaluate two different counterfactual policies. The results confirm there is a trade-off between fuel switching and scrubbing costs (with the latter having a higher investment cost and a lower variable cost), and also the existence of regional heterogeneity. Finally, the ARP implied cost savings of approximately $4.7 billions if compared to a uniform emission rate standard and $14.8 billions if compared to compulsory scrubbing for the 1995–2005 period. - Highlights: • With the cap-and-trade system of the ARP boilers had three main compliance options. • Purchase allowances; retrofit the boiler to burn low-sulfur coal; adopt scrubbers. • We develop and estimate a rigorous structural dynamic discrete choice model. • Trade-off between fuel switching and scrubbing (capital versus operating costs). • Cost savings from the ARP were substantial if compared to previous regulations.
Oxidative phosphorylation revisited
DEFF Research Database (Denmark)
Nath, Sunil; Villadsen, John
2015-01-01
The fundamentals of oxidative phosphorylation and photophosphorylation are revisited. New experimental data on the involvement of succinate and malate anions respectively in oxidative phosphorylation and photophosphorylation are presented. These new data offer a novel molecular mechanistic...
DEFF Research Database (Denmark)
Hansen, Morten Balle; Lindholst, Andrej Christian
2016-01-01
out; Benchmarking and yardstick competition; and Public-Private collaboration. On the basis of the review of the seven articles, it is found that all elements in all marketization models are firmly embedded but also under dynamic change within public service delivery systems. The review also......Purpose: The purpose of this introduction article to the IJPSM special issue on marketization is to clarify the conceptual foundations of marketization as a phenomenon within the public sector and to gauge current marketization trends on the basis of the seven articles in the special issue. Design....../methodology/approach: Conceptual clarification and cross-cutting review of seven articles analysing marketization in six countries in three policy areas at the level of local government. Findings: Four ideal-type models are deduced: Quasi-markets, involving both provider competition and free choice for users; Classic contracting...
Revisiting Okun's Relationship
Dixon, R.; Lim, G.C.; van Ours, Jan
2016-01-01
Our paper revisits Okun's relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985-2013. We find that the
Revisiting the Okun relationship
Dixon, R. (Robert); Lim, G.C.; J.C. van Ours (Jan)
2017-01-01
textabstractOur article revisits the Okun relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985–2013. We
Bounded Intention Planning Revisited
Sievers Silvan; Wehrle Martin; Helmert Malte
2014-01-01
Bounded intention planning provides a pruning technique for optimal planning that has been proposed several years ago. In addition partial order reduction techniques based on stubborn sets have recently been investigated for this purpose. In this paper we revisit bounded intention planning in the view of stubborn sets.
A Hydrostatic Paradox Revisited
Ganci, Salvatore
2012-01-01
This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…
DEFF Research Database (Denmark)
Cornean, Horia; Nenciu, Gheorghe
2009-01-01
This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant. The main mathematical tool is a regularized magnetic and geometric...
Rereading Albert B. Lord's The Singer of Tales . Revisiting the ...
African Journals Online (AJOL)
Access to a fresh set of video-recordings of Sesotho praise-poetry made in the year 2000 enabled the author to revisit his adaptation of Albert Lord's definition of the formula as a dynamic compositional device that the oral poet utilizes during delivery. The basic adaptation made in 1983 pertains to heroic praises (dithoko tsa ...
Revisiting deforestation in Africa (1990–2010): One more lost ...
African Journals Online (AJOL)
This spotlight revisits the dynamics and prognosis outlined in the late 1980's published in Déforestation en Afrique. This book on deforestation in Africa utilized available statistical data from the 1980's and was a pioneering self - styled attempt to provide a holistic viewpoint of the ongoing trends pertaining to deforestation in ...
A Multi-Level Model of Moral Functioning Revisited
Reed, Don Collins
2009-01-01
The model of moral functioning scaffolded in the 2008 "JME" Special Issue is here revisited in response to three papers criticising that volume. As guest editor of that Special Issue I have formulated the main body of this response, concerning the dynamic systems approach to moral development, the problem of moral relativism and the role of…
The nucleon mass and pion-nucleon sigma term from a chiral analysis of Nf = 2 lattice QCD world data
Directory of Open Access Journals (Sweden)
Alvarez-Ruso L.
2014-03-01
Full Text Available We investigate the pion-mass dependence of the nucleon mass within the covariant SU(2 baryon chiral perturbation theory up to order p4 with and without explicit Δ (1232 degrees of freedom. We fit lattice QCD data from several collaborations for 2 and 2+1 flavor ensembles. Here, we emphasize our Nf = 2 study where the inclusion the Δ (1232 contributions stabilizes the fits. We correct for finite volume and spacing effects, set independently the lattice QCD scale by a Sommer-scale of r0 = 0.493(23 fm and also include one σπN lQCD data point at Mπ ≈ 290 MeV. We obtain low-energy constants of natural size which are compatible with the rather linear pion-mass dependence observed in lattice QCD. We report a value of σπN = 41(5(4 MeV for the 2 flavor case and σπN = 52(3(8 MeV for 2+1 flavors.
Non-Regge and hyper-Regge effects in pion-nucleon charge exchange scattering at high energies
International Nuclear Information System (INIS)
Joynson, D.; Leader, E.; Nicolescu, B.; Paris-6 Univ., 75; Lopez, C.
1975-04-01
The experimental data on the charge exchange differential cross-section and on the difference on the π + p and π - p total cross-sections between 5GeV/c to 200GeV/c are shown to be incompatible with conventional Regge asymptotic behavior. It is shown that an additional term is required which grows in importance with energy. The precise form of the new term cannot be ascertained, but it is shown that it corresponds to a singularity at J=1 in the complex angular momentum plane. Amongst the possible types of additional term there are two which have been closely analysed: a non-Regge behavior, a hyper-Regge term which have allowed very striking predictions in particular for the charge exchange polarisation [fr
International Nuclear Information System (INIS)
Pandharipande, V.R.; Phillips, D.R.; Kolck, U. van
2005-01-01
We consider the relationship between p-wave πN scattering and the strength of the p-wave two-pion-exchange three-nucleon interaction (TPE3NI). We explain why effective theories that do not contain the Delta resonance as an explicit degree of freedom tend to overestimate the strength of the TPE3NI. The overestimation can be remedied by higher-order terms in these 'Delta-less' theories, but such terms are not yet included in state-of-the-art chiral effective field theory calculations of the nuclear force. This suggests that these calculations can predict the strength of the TPE3NI only to an accuracy of ±25%
International Nuclear Information System (INIS)
George, Phiji P.; Irodi, Aparna; Keshava, Shyamkumar N.; Lamont, Anthony C.
2014-01-01
In this article we revisit, with the help of images, those classic signs in chest radiography described by Dr Benjamin Felson himself, or other illustrious radiologists of his time, cited and discussed in 'Chest Roentgenology'. We briefly describe the causes of the signs, their utility and the differential diagnosis to be considered when each sign is seen. Wherever possible, we use CT images to illustrate the basis of some of these classic radiographic signs.
Fathi, Albert
2015-07-01
In this paper we revisit our joint work with Antonio Siconolfi on time functions. We will give a brief introduction to the subject. We will then show how to construct a Lipschitz time function in a simplified setting. We will end with a new result showing that the Aubry set is not an artifact of our proof of existence of time functions for stably causal manifolds.
Whitehead, Jim; De Bra, Paul; Grønbæk, Kaj; Larsen, Deena; Legget, John; schraefel, monica m.c.
2002-01-01
It has been 15 years since the original presentation by Frank Halasz at Hypertext'87 on seven issues for the next generation of hypertext systems. These issues are: Search and Query Composites Virtual Structures Computation in/over hypertext network Versioning Collaborative Work Extensibility and Tailorability Since that time, these issues have formed the nucleus of multiple research agendas within the Hypertext community. Befitting this direction-setting role, the issues have been revisited ...
Deterministic Graphical Games Revisited
DEFF Research Database (Denmark)
Andersson, Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro
2008-01-01
We revisit the deterministic graphical games of Washburn. A deterministic graphical game can be described as a simple stochastic game (a notion due to Anne Condon), except that we allow arbitrary real payoffs but disallow moves of chance. We study the complexity of solving deterministic graphical...... games and obtain an almost-linear time comparison-based algorithm for computing an equilibrium of such a game. The existence of a linear time comparison-based algorithm remains an open problem....
Deterministic Graphical Games Revisited
DEFF Research Database (Denmark)
Andersson, Klas Olof Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro
2012-01-01
Starting from Zermelo’s classical formal treatment of chess, we trace through history the analysis of two-player win/lose/draw games with perfect information and potentially infinite play. Such chess-like games have appeared in many different research communities, and methods for solving them......, such as retrograde analysis, have been rediscovered independently. We then revisit Washburn’s deterministic graphical games (DGGs), a natural generalization of chess-like games to arbitrary zero-sum payoffs. We study the complexity of solving DGGs and obtain an almost-linear time comparison-based algorithm...
Bottomonium spectrum revisited
Segovia, Jorge; Entem, David R.; Fernández, Francisco
2016-01-01
We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about the better way to determine their properties experimentally.
Metamorphosis in Craniiformea revisited
DEFF Research Database (Denmark)
Altenburger, Andreas; Wanninger, Andreas; Holmer, Lars E.
2013-01-01
We revisited the brachiopod fold hypothesis and investigated metamorphosis in the craniiform brachiopod Novocrania anomala. Larval development is lecithotrophic and the dorsal (brachial) valve is secreted by dorsal epithelia. We found that the juvenile ventral valve, which consists only of a thin...... brachiopods during metamorphosis to cement their pedicle to the substrate. N. anomala is therefore not initially attached by a valve but by material corresponding to pedicle cuticle. This is different to previous descriptions, which had led to speculations about a folding event in the evolution of Brachiopoda...
Revisiting Nursing Research in Nigeria
African Journals Online (AJOL)
2016-08-18
Aug 18, 2016 ... health care research, it is therefore pertinent to revisit the state of nursing research in the country. .... platforms, updated libraries with electronic resource ... benchmarks for developing countries of 26%, [17] the amount is still ...
Charles, Alexandre; Ballard, Patrick
2016-08-01
The dynamics of mechanical systems with a finite number of degrees of freedom (discrete mechanical systems) is governed by the Lagrange equation which is a second-order differential equation on a Riemannian manifold (the configuration manifold). The handling of perfect (frictionless) unilateral constraints in this framework (that of Lagrange's analytical dynamics) was undertaken by Schatzman and Moreau at the beginning of the 1980s. A mathematically sound and consistent evolution problem was obtained, paving the road for many subsequent theoretical investigations. In this general evolution problem, the only reaction force which is involved is a generalized reaction force, consistently with the virtual power philosophy of Lagrange. Surprisingly, such a general formulation was never derived in the case of frictional unilateral multibody dynamics. Instead, the paradigm of the Coulomb law applying to reaction forces in the real world is generally invoked. So far, this paradigm has only enabled to obtain a consistent evolution problem in only some very few specific examples and to suggest numerical algorithms to produce computational examples (numerical modeling). In particular, it is not clear what is the evolution problem underlying the computational examples. Moreover, some of the few specific cases in which this paradigm enables to write down a precise evolution problem are known to show paradoxes: the Painlevé paradox (indeterminacy) and the Kane paradox (increase in kinetic energy due to friction). In this paper, we follow Lagrange's philosophy and formulate the frictional unilateral multibody dynamics in terms of the generalized reaction force and not in terms of the real-world reaction force. A general evolution problem that governs the dynamics is obtained for the first time. We prove that all the solutions are dissipative; that is, this new formulation is free of Kane paradox. We also prove that some indeterminacy of the Painlevé paradox is fixed in this
Shiraishi, Junya; Miyato, Naoaki; Matsunaga, Go
2016-05-10
It is found that new channels of energy exchange between macro- and microscopic dynamics exist in plasmas. They are induced by macroscopic plasma flow. This finding is based on the kinetic-magnetohydrodynamic (MHD) theory, which analyses interaction between macroscopic (MHD-scale) motion and microscopic (particle-scale) dynamics. The kinetic-MHD theory is extended to include effects of macroscopic plasma flow self-consistently. The extension is realised by generalising an energy exchange term due to wave-particle resonance, denoted by δ WK. The first extension is generalisation of the particle's Lagrangian, and the second one stems from modification to the particle distribution function due to flow. These extensions lead to a generalised expression of δ WK, which affects the MHD stability of plasmas.
DEFF Research Database (Denmark)
Ditlevsen, Ove Dalager
2004-01-01
The derivation of the life quality index (LQI) is revisited for a revision. This revision takes into account the unpaid but necessary work time needed to stay alive in clean and healthy conditions to be fit for effective wealth producing work and to enjoyable free time. Dimension analysis...... at birth should not vary between countries. Finally the distributional assumptions are relaxed as compared to the assumptions made in an earlier work by the author. These assumptions concern the calculation of the life expectancy change due to the removal of an accident source. Moreover a simple public...... consistency problems with the standard power function expression of the LQI are pointed out. It is emphasized that the combination coefficient in the convex differential combination between the relative differential of the gross domestic product per capita and the relative differential of the expected life...
International Nuclear Information System (INIS)
Schmidt, Alexandre G M; Paiva, Milena M
2012-01-01
We revisit the quantum two-person duel. In this problem, both Alice and Bob each possess a spin-1/2 particle which models dead and alive states for each player. We review the Abbott and Flitney result—now considering non-zero α 1 and α 2 in order to decide if it is better for Alice to shoot or not the second time—and we also consider a duel where players do not necessarily start alive. This simple assumption allows us to explore several interesting special cases, namely how a dead player can win the duel shooting just once, or how can Bob revive Alice after one shot, and the better strategy for Alice—being either alive or in a superposition of alive and dead states—fighting a dead opponent. (paper)
Balcerak, Ernie
2012-12-01
In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.
Klein's double discontinuity revisited
DEFF Research Database (Denmark)
Winsløw, Carl; Grønbæk, Niels
2014-01-01
Much effort and research has been invested into understanding and bridging the ‘gaps’ which many students experience in terms of contents and expectations as they begin university studies with a heavy component of mathematics, typically in the form of calculus courses. We have several studies...... of bridging measures, success rates and many other aspects of these “entrance transition” problems. In this paper, we consider the inverse transition, experienced by university students as they revisit core parts of high school mathematics (in particular, calculus) after completing the undergraduate...... mathematics courses which are mandatory to become a high school teacher of mathematics. To what extent does the “advanced” experience enable them to approach the high school calculus in a deeper and more autonomous way ? To what extent can “capstone” courses support such an approach ? How could it be hindered...
Reframing in dentistry: Revisited
Directory of Open Access Journals (Sweden)
Sivakumar Nuvvula
2013-01-01
Full Text Available The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child′s behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice.
Zavala, Miguel A; Angulo, Oscar; Bravo de la Parra, Rafael; López-Marcos, Juan C
2007-02-07
Light competition and interspecific differences in shade tolerance are considered key determinants of forest stand structure and dynamics. Specifically two main stand diameter distribution types as a function of shade tolerance have been proposed based on empirical observations. All-aged stands of shade tolerant species tend to have steeply descending, monotonic diameter distributions (inverse J-shaped curves). Shade intolerant species in contrast typically exhibit normal (unimodal) tree diameter distributions due to high mortality rates of smaller suppressed trees. In this study we explore the generality of this hypothesis which implies a causal relationship between light competition or shade tolerance and stand structure. For this purpose we formulate a partial differential equation system of stand dynamics as a function of individual tree growth, recruitment and mortality which allows us to explore possible individual-based mechanisms--e.g. light competition-underlying observed patterns of stand structure--e.g. unimodal or inverse J-shaped equilibrium diameter curves. We find that contrary to expectations interspecific differences in growth patterns can result alone in any of the two diameter distributions types observed in the field. In particular, slow growing species can present unimodal equilibrium curves even in the absence of light competition. Moreover, light competition and shade intolerance evaluated both at the tree growth and mortality stages did not have a significant impact on stand structure that tended to converge systematically towards an inverse J-shaped curves for most tree growth scenarios. Realistic transient stand dynamics for even aged stands of shade intolerant species (unimodal curves) were only obtained when recruitment was completely suppressed, providing further evidence on the critical role played by juvenile stages of tree development (e.g. the sampling stage) on final forest structure and composition. The results also point out the
Energy Technology Data Exchange (ETDEWEB)
Li, Sile; Jarvis, Andrew [Lancaster University, Lancaster Environment Centre, Lancaster (United Kingdom)
2009-11-15
The global mean surface temperature (GMST) response of HadCM3 to a 1,000 year 4 x CO{sub 2} forcing is analysed using a transfer function methodology. We identify a third order transfer function as being an appropriate characterisation of the dynamic relationship between the radiative forcing input and GMST output of this Atmosphere-Ocean General Circulation Model (A-OGCM). From this transfer function the equilibrium climate sensitivity is estimated as 4.62 (3.92-11.88) K which is significantly higher than previously estimated for HadCM3. The response is also characterised by time constants of 4.5 (3.2-6.4), 140 (78-191) and 1,476 (564-11,737) years. The fact that the longest time constant element is significantly longer than the 1,000 year simulation run makes estimation of this element of the response problematic, highlighting the need for significantly longer model runs to express A-OGCM behaviour fully. The transfer function is interpreted in relation to a three box global energy balance model. It was found that this interpretation gave rise to three fractions of ocean heat capacity with effective depths of 63.0 (46.7-85.4), 1291.7 (787.3-2,955.3) and 2,358.0 (661.3-17,283.8) meters of seawater, associated with three discrete time constants of 4.6 (3.2-6.5), 107.7 (68.9-144.3) and 537.1 (196.2-1,243.1) years. Given this accounts for approximately 94% of the ocean heat capacity in HadCM3, it appears HadCM3 could be significantly more well mixed than previously thought when viewed on the millennial timescale. (orig.)
The critical catastrophe revisited
International Nuclear Information System (INIS)
De Mulatier, Clélia; Rosso, Alberto; Dumonteil, Eric; Zoia, Andrea
2015-01-01
The neutron population in a prototype model of nuclear reactor can be described in terms of a collection of particles confined in a box and undergoing three key random mechanisms: diffusion, reproduction due to fissions, and death due to absorption events. When the reactor is operated at the critical point, and fissions are exactly compensated by absorptions, the whole neutron population might in principle go to extinction because of the wild fluctuations induced by births and deaths. This phenomenon, which has been named critical catastrophe, is nonetheless never observed in practice: feedback mechanisms acting on the total population, such as human intervention, have a stabilizing effect. In this work, we revisit the critical catastrophe by investigating the spatial behaviour of the fluctuations in a confined geometry. When the system is free to evolve, the neutrons may display a wild patchiness (clustering). On the contrary, imposing a population control on the total population acts also against the local fluctuations, and may thus inhibit the spatial clustering. The effectiveness of population control in quenching spatial fluctuations will be shown to depend on the competition between the mixing time of the neutrons (i.e. the average time taken for a particle to explore the finite viable space) and the extinction time
International Nuclear Information System (INIS)
Towner, I.S.; Khanna, F.C.
1984-01-01
Consideration of core polarization, isobar currents and meson-exchange processes gives a satisfactory understanding of the ground-state magnetic moments in closed-shell-plus (or minus)-one nuclei, A = 3, 15, 17, 39 and 41. Ever since the earliest days of the nuclear shell model the understanding of magnetic moments of nuclear states of supposedly simple configurations, such as doubly closed LS shells +-1 nucleon, has been a challenge for theorists. The experimental moments, which in most cases are known with extraordinary precision, show a small yet significant departure from the single-particle Schmidt values. The departure, however, is difficult to evaluate precisely since, as will be seen, it results from a sensitive cancellation between several competing corrections each of which can be as large as the observed discrepancy. This, then, is the continuing fascination of magnetic moments. In this contribution, we revisit the subjet principally to identify the role played by isobar currents, which are of much concern at this conference. But in so doing we warn quite strongly of the dangers of considering just isobar currents in isolation; equal consideration must be given to competing processes which in this context are the mundane nuclear structure effects, such as core polarization, and the more popular meson-exchange currents
Lorentz violation naturalness revisited
Energy Technology Data Exchange (ETDEWEB)
Belenchia, Alessio; Gambassi, Andrea; Liberati, Stefano [SISSA - International School for Advanced Studies, via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste (Italy)
2016-06-08
We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.
Leadership and Management Theories Revisited
DEFF Research Database (Denmark)
Madsen, Mona Toft
2001-01-01
The goal of the paper is to revisit and analyze key contributions to the understanding of leadership and management. As a part of the discussion a role perspective that allows for additional and/or integrated leader dimensions, including a change-centered, will be outlined. Seemingly, a major...
Revisiting Inter-Genre Similarity
DEFF Research Database (Denmark)
Sturm, Bob L.; Gouyon, Fabien
2013-01-01
We revisit the idea of ``inter-genre similarity'' (IGS) for machine learning in general, and music genre recognition in particular. We show analytically that the probability of error for IGS is higher than naive Bayes classification with zero-one loss (NB). We show empirically that IGS does...... not perform well, even for data that satisfies all its assumptions....
'Counterfeit deviance' revisited.
Griffiths, Dorothy; Hingsburger, Dave; Hoath, Jordan; Ioannou, Stephanie
2013-09-01
The field has seen a renewed interest in exploring the theory of 'counterfeit deviance' for persons with intellectual disability who sexually offend. The term was first presented in 1991 by Hingsburger, Griffiths and Quinsey as a means to differentiate in clinical assessment a subgroup of persons with intellectual disability whose behaviours appeared like paraphilia but served a function that was not related to paraphilia sexual urges or fantasies. Case observations were put forward to provide differential diagnosis of paraphilia in persons with intellectual disabilities compared to those with counterfeit deviance. The brief paper was published in a journal that is no longer available and as such much of what is currently written on the topic is based on secondary sources. The current paper presents a theoretical piece to revisit the original counterfeit deviance theory to clarify the myths and misconceptions that have arisen and evaluate the theory based on additional research and clinical findings. The authors also propose areas where there may be a basis for expansion of the theory. The theory of counterfeit deviance still has relevance as a consideration for clinicians when assessing the nature of a sexual offence committed by a person with an intellectual disability. Clinical differentiation of paraphilia from counterfeit deviance provides a foundation for intervention that is designed to specifically treat the underlying factors that contributed to the offence for a given individual. Counterfeit deviance is a concept that continues to provide areas for consideration for clinicians regarding the assessment and treatment of an individual with an intellectual disability who has sexually offended. It is not and never was an explanation for all sexually offending behavior among persons with intellectual disabilities. © 2013 John Wiley & Sons Ltd.
Gaussian entanglement revisited
Lami, Ludovico; Serafini, Alessio; Adesso, Gerardo
2018-02-01
We present a novel approach to the separability problem for Gaussian quantum states of bosonic continuous variable systems. We derive a simplified necessary and sufficient separability criterion for arbitrary Gaussian states of m versus n modes, which relies on convex optimisation over marginal covariance matrices on one subsystem only. We further revisit the currently known results stating the equivalence between separability and positive partial transposition (PPT) for specific classes of Gaussian states. Using techniques based on matrix analysis, such as Schur complements and matrix means, we then provide a unified treatment and compact proofs of all these results. In particular, we recover the PPT-separability equivalence for: (i) Gaussian states of 1 versus n modes; and (ii) isotropic Gaussian states. In passing, we also retrieve (iii) the recently established equivalence between separability of a Gaussian state and and its complete Gaussian extendability. Our techniques are then applied to progress beyond the state of the art. We prove that: (iv) Gaussian states that are invariant under partial transposition are necessarily separable; (v) the PPT criterion is necessary and sufficient for separability for Gaussian states of m versus n modes that are symmetric under the exchange of any two modes belonging to one of the parties; and (vi) Gaussian states which remain PPT under passive optical operations can not be entangled by them either. This is not a foregone conclusion per se (since Gaussian bound entangled states do exist) and settles a question that had been left unanswered in the existing literature on the subject. This paper, enjoyable by both the quantum optics and the matrix analysis communities, overall delivers technical and conceptual advances which are likely to be useful for further applications in continuous variable quantum information theory, beyond the separability problem.
Ellsworth, W. L.; Bulut, F.
2016-12-01
Much of what we know about the initiation of earthquakes comes from the temporal and spatial relationship of foreshocks to the initiation point of the mainshock. The 1999 Mw 7.6 Izmit, Turkey, earthquake was preceded by a 44 minute-long foreshock sequence. Bouchon et al. (Science, 2011) analyzed the foreshocks using a single seismic station, UCG, located to the north of the east-west fault, and concluded on the basis of waveform similarity that the foreshocks repeatedly re-ruptured the same fault patch, driven by slow slip at the base of the crust. We revisit the foreshock sequence using seismograms from 9 additional stations that recorded the four largest foreshocks (Mw 2.0 to 2.8) to better characterize spatial and temporal evolution of the foreshock sequence and their relationship to the mainshock hypocenter. Cross-correlation timing and hypocentroid location with hypoDD reveals a systematic west-to-east propagation of the four largest foreshocks toward the mainshock hypocenter. Foreshock rupture dimensions estimated using spectral ratios imply no major overlap for the first three foreshocks. The centroid of 4th and largest foreshock continues the eastward migration, but lies within the circular source area of the 3rd. The 3rd, however, has a low stress drop and strong directivity to the west . The mainshock hypocenter locates on the eastern edge of foreshock 4. We also re-analyzed waveform similarity of all 18 foreshocks recorded at UCG by removing the common mode signal and clustering the residual seismogram using the correlation coefficient as the distance metric. The smaller foreshocks cluster with the larger events in time order, sometimes as foreshocks and more commonly as aftershocks. These observations show that the Izmit foreshock sequence is consistent with a stress-transfer driven cascade, moving systematically to the east along the fault and that there is no observational requirement for creep as a driving mechanism.
Remembered Experiences and Revisit Intentions
DEFF Research Database (Denmark)
Barnes, Stuart; Mattsson, Jan; Sørensen, Flemming
2016-01-01
Tourism is an experience-intensive sector in which customers seek and pay for experiences above everything else. Remembering past tourism experiences is also crucial for an understanding of the present, including the predicted behaviours of visitors to tourist destinations. We adopt a longitudinal...... approach to memory data collection from psychological science, which has the potential to contribute to our understanding of tourist behaviour. In this study, we examine the impact of remembered tourist experiences in a safari park. In particular, using matched survey data collected longitudinally and PLS...... path modelling, we examine the impact of positive affect tourist experiences on the development of revisit intentions. We find that longer-term remembered experiences have the strongest impact on revisit intentions, more so than predicted or immediate memory after an event. We also find that remembered...
Revisiting Mutual Fund Performance Evaluation
Angelidis, Timotheos; Giamouridis, Daniel; Tessaromatis, Nikolaos
2012-01-01
Mutual fund manager excess performance should be measured relative to their self-reported benchmark rather than the return of a passive portfolio with the same risk characteristics. Ignoring the self-reported benchmark introduces biases in the measurement of stock selection and timing components of excess performance. We revisit baseline empirical evidence in mutual fund performance evaluation utilizing stock selection and timing measures that address these biases. We introduce a new factor e...
Early-Transition Output Decline Revisited
Directory of Open Access Journals (Sweden)
Crt Kostevc
2016-05-01
Full Text Available In this paper we revisit the issue of aggregate output decline that took place in the early transition period. We propose an alternative explanation of output decline that is applicable to Central- and Eastern-European countries. In the first part of the paper we develop a simple dynamic general equilibrium model that builds on work by Gomulka and Lane (2001. In particular, we consider price liberalization, interpreted as elimination of distortionary taxation, as a trigger of the output decline. We show that price liberalization in interaction with heterogeneous adjustment costs and non-employment benefits lead to aggregate output decline and surge in wage inequality. While these patterns are consistent with actual dynamics in CEE countries, this model cannot generate output decline in all sectors. Instead sectors that were initially taxed even exhibit output growth. Thus, in the second part we consider an alternative general equilibrium model with only one production sector and two types of labor and distortion in a form of wage compression during the socialist era. The trigger for labor mobility and consequently output decline is wage liberalization. Assuming heterogeneity of workers in terms of adjustment costs and non-employment benefits can explain output decline in all industries.
Sea quark matrix elements and flavor singlet spectroscopy on the lattice
International Nuclear Information System (INIS)
Lagae, J.F.
1996-01-01
I summarize the results of three recent lattice studies which use stochastic estimator techniques in order to investigate the flavor singlet dynamics in QCD. These include a measurement of the pion-nucleon σ-term, the computation of the flavor singlet axial coupling constant of the nucleon and a determination of flavor singlet meson screening lengths in finite temperature QCD
Moment tensor decompositions revisited
Czech Academy of Sciences Publication Activity Database
Vavryčuk, Václav
2015-01-01
Roč. 19, č. 1 (2015), s. 231-252 ISSN 1383-4649 R&D Projects: GA ČR(CZ) GAP210/12/1491 Institutional support: RVO:67985530 Keywords : dynamics and mechanics of faulting * earthquake source observations * seismic anisotropy * theoretical seismology Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.550, year: 2015
Revisiting Absorptive Capacity
DEFF Research Database (Denmark)
de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher
Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary...... learning processes of absorptive capacity, which comprise combinative and adaptive capabilities. Drawing on survey data (n=169), the study concludes that combinative capabilities primarily enhance transformative and exploratory learning processes, while adaptive capabilities strengthen all three learning...
International Nuclear Information System (INIS)
Brandenberger, R.H.
1986-01-01
Cosmological phase transitions are examined using a new approach based on the dynamical analysis of the equations of motion of quantum fields rather than on static effective potential considerations. In many models the universe enters a period of exponential expansion required for an inflationary cosmology. Analytical methods show that this will be the case if the interaction rate due to quantum field nonlinearities is small compared to the expansion rate of the universe. They derive a heuristic criterion for the maximal value of the coupling constant for which they expect inflation. The prediction is in good agreement with numerical results
Irreversible investments revisited
DEFF Research Database (Denmark)
Sandal, Leif K.; Steinshamn, Stein I.; Hoff, Ayoe
2007-01-01
A multi-dimensional, non-linear dynamic model in continuous time is presented for the purpose of finding the optimal combination of exploitation and capital investment in optimal renewable resource management. Non-malleability of capital is incorporated in the model through an asymmetric cost......-function of investment, and investments can be both positive and negative. Exploitation is controlled through the utilisation rate of available capital. A novel feature in this model is that there are costs associated with the available capital whether it is utilised or not. And, in contrast to most of the previous...
International Nuclear Information System (INIS)
Sauermann, C.
1993-05-01
In the first part of the thesis the ηNN * coupling constant is determined. The model must contain both elastic πN scattering and ηproduction by excitation of the resonance and subsequent decay into an ηmeson and a nucleon. By fitting to the experimental data, which are present as real and imaginary part of the T matrix in the S 11 channel, the unknown coupling constants are determined. It is proved that unconditionally also the N * (1650) resonance must be regarded in order to reproduce the data well. The N * (1650) couples strongly to the pion and weakly to two pions, but scarcely to the ηmeson. The coupling to two pions is simulated in our model by introduction of an additional pseudoscalar meson of the mass 400 MeV. First a T matrix calculation is performed, in which the self-energy of the two resonances are regarded. In order to reach independence on the cutoffs subsequently the T matrix is calculated by means of the K matrix formalism. Finally an effective ηNN * coupling constant of 1.4 is found. In the second part of the thesis then with this coupling constant the behaviour of the ηmeson in nuclear matter at different densities is studied. (HSI)
Energy Technology Data Exchange (ETDEWEB)
Alarcon, Jose Manuel [Mainz Univ. (Germany). Inst. fuer Kernphysik; Camalich, Jorge Martin [Department of Physics and Astronomy, University of Sussex, Brighton (United Kingdom); Oller, Jose Antonio [Murcia Univ. (Spain). Dept. de Fisica
2013-07-01
In this talk I present the community our recent determinations of σ{sub πN} and σ{sub s} employing covariant baryon chiral perturbation theory and updated experimental information. We show how these determinations overcome the difficulties that the old values of σ{sub πN}=45 MeV and y∼0.23 have when trying to explain the modern experiments regarding the nuclear structure and LQCD determinations. From our results, a new scenario emerges where σ{sub πN} and σ{sub s} are in good agreement with updated phenomenology and recent LQCD calculations.
Energy Technology Data Exchange (ETDEWEB)
dos Reis, Alberto Correa [Rio de Janeiro, CBPF
1992-04-01
This work a presents a measurement of the total cross section for the charmed baryon $\\Lambda_c$ times the branching fraction of the mode $\\Lambda_c \\to pK\\bar{\\mu}$, for the kinematical region $x_F$ > O in $\\pi$-nucleus interactions at 250 GeV/c. This measurement is made with data from the experiment E769, collected during 1987/1988 at the FERMILAB Tagged Photon Laboratory. A segmented target of berillium, aluminum, copper and tungsten was used. Based on the A dependence measurement, made by E769, and on the available branching fractions, the total cross section per nucleon is calculated. The result is compared with other experiments and with some theoretical predictions inspired on QCD.
Directory of Open Access Journals (Sweden)
Christopher Tyler
2012-05-01
Full Text Available One of the most fascinating phenomena in stereopsis is the profound hysteresis effect reported by Fender and Julesz (1967, in which the depth percept persisted with increasing disparity long past the point at which depth was recovered with decreasing disparity. To control retinal disparity without vergence eye movements, they stabilized the stimuli on the retinas with an eye tracker. I now report that stereo hysteresis can be observed directly in printed stereograms simply by rotating the image. As the stereo image rotates, the horizontal disparities rotate to become vertical, then horizontal with inverted sign, and then vertical again before returning to the original orientation. The depth shows an interesting popout effect, almost as though the depth was turning on and off rapidly, despite the inherently sinusoidal change in the horizontal disparity vector. This stimulus was generated electronically in a circular format so that the random-dot field could be dynamically replaced, eliminating any cue to cyclorotation. Noise density was scaled with eccentricity to fade out the stimulus near fixation. For both the invariant and the dynamic noise, profound hysteresis of several seconds delay was found in six observers. This was far longer than the reaction time to respond to changes in disparity, which was less than a second. Purely horizontal modulation of disparity to match the horizontal vector component of the disparity rotation did not show the popout effect, which thus seems to be a function of the interaction between horizontal and vertical disparities and may be attributable to depth interpolation processes.
Revisiting event horizon finders
International Nuclear Information System (INIS)
Cohen, Michael I; Pfeiffer, Harald P; Scheel, Mark A
2009-01-01
Event horizons are the defining physical features of black hole spacetimes, and are of considerable interest in studying black hole dynamics. Here, we reconsider three techniques to find event horizons in numerical spacetimes: integrating geodesics, integrating a surface, and integrating a level-set of surfaces over a volume. We implement the first two techniques and find that straightforward integration of geodesics backward in time is most robust. We find that the exponential rate of approach of a null surface towards the event horizon of a spinning black hole equals the surface gravity of the black hole. In head-on mergers we are able to track quasi-normal ringing of the merged black hole through seven oscillations, covering a dynamic range of about 10 5 . Both at late times (when the final black hole has settled down) and at early times (before the merger), the apparent horizon is found to be an excellent approximation of the event horizon. In the head-on binary black hole merger, only some of the future null generators of the horizon are found to start from past null infinity; the others approach the event horizons of the individual black holes at times far before merger.
Schroedinger's variational method of quantization revisited
International Nuclear Information System (INIS)
Yasue, K.
1980-01-01
Schroedinger's original quantization procedure is revisited in the light of Nelson's stochastic framework of quantum mechanics. It is clarified why Schroedinger's proposal of a variational problem led us to a true description of quantum mechanics. (orig.)
Tourists' perceptions and intention to revisit Norway
Lazar, Ana Florina; Komolikova-Blindheim, Galyna
2016-01-01
Purpose - The overall purpose of this study is to explore tourists' perceptions and their intention to revisit Norway. The aim is to find out what are the factors that drive the overall satisfaction, the willingness to recommend and the revisit intention of international tourists that spend their holiday in Norway. Design-Method-Approach - the Theory of Planned Behavior (Ajzen 1991), is used as a framework to investigate tourists' intention and behavior towards Norway as destination. The o...
Irreversible investments revisited
DEFF Research Database (Denmark)
Sandal, Leif K.; Steinshamn, Stein I.; Hoff, Ayoe
2007-01-01
A multi-dimensional, non-linear dynamic model in continuous time is presented for the purpose of finding the optimal combination of exploitation and capital investment in optimal renewable resource management. Non-malleability of capital is incorporated in the model through an asymmetric cost......-function of investment, and investments can be both positive and negative. Exploitation is controlled through the utilisation rate of available capital. A novel feature in this model is that there are costs associated with the available capital whether it is utilised or not. And, in contrast to most of the previous...... literature, the state variables, namely the physical capital and the biological resource, enter the objective function. Due to the nonlinearities in this model some of the results are in sharp contrast to previous literature....
The Compton generator revisited
Siboni, S.
2014-09-01
The Compton generator, introduced in 1913 by the US physicist A H Compton as a relatively simple device to detect the Earth's rotation with respect to the distant stars, is analyzed and discussed in a general perspective. The paper introduces a generalized definition of the generator, emphasizing the special features of the original apparatus, and provides a suggestive interpretation of the way the device works. To this end, an intriguing electromagnetic analogy is developed, which turns out to be particularly useful in simplifying the calculations. Besides the more extensive description of the Compton generator in itself, the combined use of concepts and methods coming from different fields of physics, such as particle dynamics in moving references frames, continuum mechanics and electromagnetism, may be of interest to both teachers and graduate students.
International Nuclear Information System (INIS)
Chialva, Diego; Danielsson, Ulf H
2008-01-01
This paper represents an in-depth treatment of the chain inflation scenario. We fully determine the evolution of the universe in the model, the conditions necessary in order to have a successful inflationary period, and the matching with the observational results regarding the cosmological perturbations. We study in great detail, and in general, the dynamics of the background, as well as the mechanism of generation of the perturbations. We also find an explicit formula for the spectrum of adiabatic perturbations. Our results prove that chain inflation is a viable model for solving the horizon, entropy and flatness problems of standard cosmology and for generating the right amount of adiabatic cosmological perturbations. The results are radically different from those found in previous works on the subject. Finally, we argue that there is a natural way to embed chain inflation into flux compactified string theory. We discuss the details of the implementation and how to fit observations
THE FARMLAND VALUATION REVISITED
Directory of Open Access Journals (Sweden)
Xin Li
2016-04-01
Full Text Available Empirical research is scarce concerning the dynamics of farmland markets which inspire the decision to sell farmlands. This paper explores the real option to postpone the sale of land in farmland valuation. In this article, a real options approach is used to analyze farmland prices behavior using historical cash flow and land price information for Illinois. In general, rising farmland values are primarily dependent on agricultural commodity prices and interest rates. Results suggest that uncertainty about future growth and capital gains is a significant component of farmland market value. Furthermore, this research examines several shift factors of the option value of the state’s farmland by taking into account of uncertainty to improve the analysis of farmland market values.
Coded aperture tomography revisited
International Nuclear Information System (INIS)
Bizais, Y.; Rowe, R.W.; Zubal, I.G.; Bennett, G.W.; Brill, A.B.
1983-01-01
Coded aperture (CA) Tomography never achieved wide spread use in Nuclear Medicine, except for the degenerate case of Seven Pinhole tomagraphy (7PHT). However it enjoys several attractive features (high sensitivity and tomographic ability with a statis detector). On the other hand, resolution is usually poor especially along the depth axis and the reconstructed volume is rather limited. Arguments are presented justifying the position that CA tomography can be useful for imaging time-varying 3D structures, if its major drawbacks (poor longitudinal resolution and difficulty in quantification) are overcome. Poor results obtained with 7PHT can be explained by both a very limited angular range sampled and a crude modelling of the image formation process. Therefore improvements can be expected by the use of a dual-detector system, along with a better understanding of its sampling properties and the use of more powerful reconstruction algorithms. Non overlapping multipinhole plates, because they do not involve a decoding procedure, should be considered first for practical applications. Use of real CA should be considered for cases in which non overlapping multipinhole plates do not lead to satisfactory solutions. We have been and currently are carrying out theoretical and experimental works, in order to define the factors which limit CA imaging and to propose satisfactory solutions for Dynamic Emission Tomography
Directory of Open Access Journals (Sweden)
Cristina Capineri
2016-07-01
Full Text Available Drawing on John Agnew’s (1987 theoretical framework for the analysis of place (location, locale and sense of place and on Doreen Massey’s (1991 interpretation of Kilburn High Road (London, the contribution develops an analysis of the notion of place in the case study of Kilburn High Road by comparing the semantics emerging from Doreen Massey’s interpretation of Kilburn High Road in the late Nineties with those from a selection of noisy and unstructured volunteered geographic information collected from Flickr photos and Tweets harvested in 2014–2015. The comparison shows how sense of place is dynamic and changing over time and explores Kilburn High Road through the categories of location, locale and sense of place derived from the qualitative analysis of VGI content and annotations. The contribution shows how VGI can contribute to discovering the unique relationship between people and place which takes the form given by Doreen Massey to Kilburn High Road and then moves on to the many forms given by people experiencing Kilburn High Road through a photo, a Tweet or a simple narrative. Finally, the paper suggests that the analysis of VGI content can contribute to detect the relevant features of street life, from infrastructure to citizens’ perceptions, which should be taken into account for a more human-centered approach in planning or service management.
Revisiting the destiny compulsion.
Potamianou, Anna
2017-02-01
This paper is an attempt to deal with some questions raised by the so-called 'compulsion of destiny' constellation. In presenting the standpoints of Freud and of psychoanalysts who after him were concerned with this problematic, the author takes the view that several aspects of the configuration merit further discussion. Accordingly, the dynamics of repetition compulsion, the complexity of the projective strategy, the coexistence of passive and omnipotent trends are considered. Concerning compulsive repetitions the dimension of drive intrication is underlined, thus moderating the understanding of this clinical entity as mainly related to death drive trends. Projection is understood as serving complex psychic demands. The coexistence of passive and omnipotent trends is envisaged, as manifested in phantasies of submission / participation of patients to a force that exceeds human limitations. For certain cases the consonance of somatic and psychic experiences is noted. Finally, elements from the material of two cases are presented which pertain to the problematic of the compulsion of destiny in which random events are submitted to heavy psychic necessities. Copyright © 2016 Institute of Psychoanalysis.
Personal disclosure revisited.
Olarte, Silvia W
2003-01-01
In this paper personal disclosure is defined as a conscious verbal presentation to the patient by the therapist of a personal vignette accompanied by the appropriate dynamic formulation and resolution of a given personal area of conflict. It is conceptualized within theoretical formulations which consider the therapeutic relationship a dyad, where the reality of the patient and the reality of the therapist influence each other, providing the matrix through which the resolution of the patient's past life experiences takes place in the context of this new interpersonal experience. It is specifically differentiated from a boundary violation, because the personal disclosure is brought to the patient's interactional awareness not for gratification of the therapist's sexual or narcissistic needs, but to provoke a response in the patient's conceptualization of a phenomenon being presented in the session and to actively influence the intersubjective field. Within the conceptual framework developed in this paper, personal disclosure reaffirms the patient's current self-discovery and provides for a different formative experience. Personal disclosure is not to be used by the therapist as a vehicle to resolve personal conflicts or as source of personal gratification. When used within the context developed in this paper, personal disclosure enhances both the patient's therapeutic process and the therapist's ever-evolving growth.
Mutated hilltop inflation revisited
Pal, Barun Kumar
2018-05-01
In this work we re-investigate pros and cons of mutated hilltop inflation. Applying Hamilton-Jacobi formalism we solve inflationary dynamics and find that inflation goes on along the {W}_{-1} branch of the Lambert function. Depending on the model parameter mutated hilltop model renders two types of inflationary solutions: one corresponds to small inflaton excursion during observable inflation and the other describes large field inflation. The inflationary observables from curvature perturbation are in tune with the current data for a wide range of the model parameter. The small field branch predicts negligible amount of tensor to scalar ratio r˜ O(10^{-4}), while the large field sector is capable of generating high amplitude for tensor perturbations, r˜ O(10^{-1}). Also, the spectral index is almost independent of the model parameter along with a very small negative amount of scalar running. Finally we find that the mutated hilltop inflation closely resembles the α -attractor class of inflationary models in the limit of α φ ≫ 1.
International Nuclear Information System (INIS)
Bogolubov, N.N. Jr.; Prykarpatsky, A.K.; Ufuk Taneri
2008-07-01
The main fundamental principles characterizing the vacuum field structure are formulated and the modeling of the related vacuum medium and charged point particle dynamics by means of de- vised field theoretic tools are analyzed. The Maxwell electrodynamic theory is revisited and newly derived from the suggested vacuum field structure principles and the classical special relativity theory relationship between the energy and the corresponding point particle mass is revisited and newly obtained. The Lorentz force expression with respect to arbitrary non-inertial reference frames is revisited and discussed in detail, and some new interpretations of relations between the special relativity theory and quantum mechanics are presented. The famous quantum-mechanical Schroedinger type equations for a relativistic point particle in the external potential and magnetic fields within the quasiclassical approximation as the Planck constant (h/2π) → 0 and the light velocity c → ∞ are obtained. (author)
Hidden ion population: Revisited
International Nuclear Information System (INIS)
Olsen, R.C.; Chappell, C.R.; Gallagher, D.L.; Green, J.L.; Gurnett, D.A.
1985-01-01
Satellite potentials in the outer plasmasphere range from near zero to +5 to +10 V. Under such conditions ion measurements may not include the low energy core of the plasma population. In eclipse, the photoelectron current drops to zero, and the spacecraft potential can drop to near zero volts. In regions where the ambient plasma density is below 100 cm -3 , previously unobserved portions of the ambient plasma distribution function can become visible in eclipse. A survey of the data obtained from the retarding ion mass spectrometer (RIMS) on Dynamics Explorer 1 shows that the RIMS detector generally measured the isotropic background in both sunlight and eclipse in the plasma-sphere. Absolute density measurements for the ''hidden'' ion population are obtained for the first time using the plasma wave instrument observations of the upper hybrid resonance. Agreement in total density is found in sunlight and eclipse measurements at densities above 80 cm -3 . In eclipse, agreement is found at densities as low as 20 cm -3 . The isotropic plasma composition is primarily H + , with approx.10% He + , and 0.1 to 1.0% O + . A low energy field-aligned ion population appears in eclipse measurements outside the plasmasphere, which is obscured in sunlight. These field-aligned ions can be interpreted as field-aligned flows with densities of a few particles per cubic centimeter, flowing at 5-20 km/s. The problem in measuring these field-aligned flows in sunlight is the masking of the high energy tail of the field-aligned distribution by the isotropic background. Effective measurement of the core of the magnetospheric plasma distribution awaits satellites with active means of controlling the satellite potential
Re-visiting RHIC snakes: OPERA fields, n_{0} dance
Energy Technology Data Exchange (ETDEWEB)
Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Gupta, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States)
2017-09-22
In this Tech. Note RHIC snakes and stable spin direction $\\vector{n}$_{0}(s) are re-visited, based on OPERA-computed field maps of the former. The numerical simulations so undertaken provide various outcomes regarding RHIC optics and spin dynamics, in relation with orbital and focusing effects resulting from the use of this realistic 3-D representation of the snakes.
The climate continuum revisited
Emile-Geay, J.; Wang, J.; Partin, J. W.
2015-12-01
A grand challenge of climate science is to quantify the extent of natural variability on adaptation-relevant timescales (10-100y). Since the instrumental record is too short to adequately estimate the spectra of climate measures, this information must be derived from paleoclimate proxies, which may harbor a many-to-one, non-linear (e.g. thresholded) and non-stationary relationship to climate. In this talk, I will touch upon the estimation of climate scaling behavior from climate proxies. Two case studies will be presented: an investigation of scaling behavior in a reconstruction of global surface temperature using state-of- the-art data [PAGES2K Consortium, in prep] and methods [Guillot et al., 2015]. Estimating the scaling exponent β in spectra derived from this reconstruction, we find that 0 long-term memory. Overall, the reconstruction-based spectra are steeper than the ones based on an instrumental dataset [HadCRUT4.2, Morice et al., 2012], and those estimated from PMIP3/CMIP5 models, suggesting the climate system is more energetic at multidecadal to centennial timescales than can be inferred from the short instrumental record or from the models developed to reproduce it [Laepple and Huybers, 2014]. an investigation of scaling behavior in speleothems records of tropical hydroclimate. We will make use of recent advances in proxy system modeling [Dee et al., 2015] and investigate how various aspects of the speleothem system (karst dynamics, age uncertainties) may conspire to bias the estimate of scaling behavior from speleothem timeseries. The results suggest that ignoring such complications leads to erroneous inferences about hydroclimate scaling. References Dee, S. G., J. Emile-Geay, M. N. Evans, Allam, A., D. M. Thompson, and E. J. Steig (2015), J. Adv. Mod. Earth Sys., 07, doi:10.1002/2015MS000447. Guillot, D., B. Rajaratnam, and J. Emile-Geay (2015), Ann. Applied. Statist., pp. 324-352, doi:10.1214/14-AOAS794. Laepple, T., and P. Huybers (2014), PNAS, doi
The Levy sections theorem revisited
International Nuclear Information System (INIS)
Figueiredo, Annibal; Gleria, Iram; Matsushita, Raul; Silva, Sergio Da
2007-01-01
This paper revisits the Levy sections theorem. We extend the scope of the theorem to time series and apply it to historical daily returns of selected dollar exchange rates. The elevated kurtosis usually observed in such series is then explained by their volatility patterns. And the duration of exchange rate pegs explains the extra elevated kurtosis in the exchange rates of emerging markets. In the end, our extension of the theorem provides an approach that is simpler than the more common explicit modelling of fat tails and dependence. Our main purpose is to build up a technique based on the sections that allows one to artificially remove the fat tails and dependence present in a data set. By analysing data through the lenses of the Levy sections theorem one can find common patterns in otherwise very different data sets
The power reinforcement framework revisited
DEFF Research Database (Denmark)
Nielsen, Jeppe; Andersen, Kim Normann; Danziger, James N.
2016-01-01
Whereas digital technologies are often depicted as being capable of disrupting long-standing power structures and facilitating new governance mechanisms, the power reinforcement framework suggests that information and communications technologies tend to strengthen existing power arrangements within...... public organizations. This article revisits the 30-yearold power reinforcement framework by means of an empirical analysis on the use of mobile technology in a large-scale programme in Danish public sector home care. It explores whether and to what extent administrative management has controlled decision......-making and gained most benefits from mobile technology use, relative to the effects of the technology on the street-level workers who deliver services. Current mobile technology-in-use might be less likely to be power reinforcing because it is far more decentralized and individualized than the mainly expert...
The Levy sections theorem revisited
Figueiredo, Annibal; Gleria, Iram; Matsushita, Raul; Da Silva, Sergio
2007-06-01
This paper revisits the Levy sections theorem. We extend the scope of the theorem to time series and apply it to historical daily returns of selected dollar exchange rates. The elevated kurtosis usually observed in such series is then explained by their volatility patterns. And the duration of exchange rate pegs explains the extra elevated kurtosis in the exchange rates of emerging markets. In the end, our extension of the theorem provides an approach that is simpler than the more common explicit modelling of fat tails and dependence. Our main purpose is to build up a technique based on the sections that allows one to artificially remove the fat tails and dependence present in a data set. By analysing data through the lenses of the Levy sections theorem one can find common patterns in otherwise very different data sets.
Revisiting tourist behavior via destination brand worldness
Directory of Open Access Journals (Sweden)
Murat Kayak
2016-11-01
Full Text Available Taking tourists’ perspective rather than destination offerings as its core concept, this study introduces “perceived destination brand worldness” as a variable. Perceived destination brand worldness is defined as the positive perception that a tourist has of a country that is visited by tourists from all over the world. Then, the relationship between perceived destination brand worldness and intention to revisit is analyzed using partial least squares regression. This empirical study selects Taiwanese tourists as its sample, and the results show that perceived destination brand worldness is a direct predictor of intention to revisit. In light of these empirical findings and observations, practical and theoretical implications are discussed.
Goodman, Lawrence E
2001-01-01
Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.
Leukemia and ionizing radiation revisited
Energy Technology Data Exchange (ETDEWEB)
Cuttler, J.M. [Cuttler & Associates Inc., Vaughan, Ontario (Canada); Welsh, J.S. [Loyola University-Chicago, Dept. or Radiation Oncology, Stritch School of Medicine, Maywood, Illinois (United States)
2016-03-15
A world-wide radiation health scare was created in the late 19508 to stop the testing of atomic bombs and block the development of nuclear energy. In spite of the large amount of evidence that contradicts the cancer predictions, this fear continues. It impairs the use of low radiation doses in medical diagnostic imaging and radiation therapy. This brief article revisits the second of two key studies, which revolutionized radiation protection, and identifies a serious error that was missed. This error in analyzing the leukemia incidence among the 195,000 survivors, in the combined exposed populations of Hiroshima and Nagasaki, invalidates use of the LNT model for assessing the risk of cancer from ionizing radiation. The threshold acute dose for radiation-induced leukemia, based on about 96,800 humans, is identified to be about 50 rem, or 0.5 Sv. It is reasonable to expect that the thresholds for other cancer types are higher than this level. No predictions or hints of excess cancer risk (or any other health risk) should be made for an acute exposure below this value until there is scientific evidence to support the LNT hypothesis. (author)
Individualist Biocentrism vs. Holism Revisited
Directory of Open Access Journals (Sweden)
Katie McShane
2014-06-01
Full Text Available While holist views such as ecocentrism have considerable intuitive appeal, arguing for the moral considerability of ecological wholes such as ecosystems has turned out to be a very difficult task. In the environmental ethics literature, individualist biocentrists have persuasively argued that individual organisms—but not ecological wholes—are properly regarded as having a good of their own . In this paper, I revisit those arguments and contend that they are fatally flawed. The paper proceeds in five parts. First, I consider some problems brought about by climate change for environmental conservation strategies and argue that these problems give us good pragmatic reasons to want a better account of the welfare of ecological wholes. Second, I describe the theoretical assumptions from normative ethics that form the background of the arguments against holism. Third, I review the arguments given by individualist biocentrists in favour of individualism over holism. Fourth, I review recent work in the philosophy of biology on the units of selection problem, work in medicine on the human biome, and work in evolutionary biology on epigenetics and endogenous viral elements. I show how these developments undermine both the individualist arguments described above as well as the distinction between individuals and wholes as it has been understood by individualists. Finally, I consider five possible theoretical responses to these problems.
Revisiting the safety of aspartame.
Choudhary, Arbind Kumar; Pretorius, Etheresia
2017-09-01
Aspartame is a synthetic dipeptide artificial sweetener, frequently used in foods, medications, and beverages, notably carbonated and powdered soft drinks. Since 1981, when aspartame was first approved by the US Food and Drug Administration, researchers have debated both its recommended safe dosage (40 mg/kg/d) and its general safety to organ systems. This review examines papers published between 2000 and 2016 on both the safe dosage and higher-than-recommended dosages and presents a concise synthesis of current trends. Data on the safe aspartame dosage are controversial, and the literature suggests there are potential side effects associated with aspartame consumption. Since aspartame consumption is on the rise, the safety of this sweetener should be revisited. Most of the literature available on the safety of aspartame is included in this review. Safety studies are based primarily on animal models, as data from human studies are limited. The existing animal studies and the limited human studies suggest that aspartame and its metabolites, whether consumed in quantities significantly higher than the recommended safe dosage or within recommended safe levels, may disrupt the oxidant/antioxidant balance, induce oxidative stress, and damage cell membrane integrity, potentially affecting a variety of cells and tissues and causing a deregulation of cellular function, ultimately leading to systemic inflammation. © The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Neutrino assisted GUT baryogenesis revisited
Huang, Wei-Chih; Päs, Heinrich; Zeißner, Sinan
2018-03-01
Many grand unified theory (GUT) models conserve the difference between the baryon and lepton number, B -L . These models can create baryon and lepton asymmetries from heavy Higgs or gauge boson decays with B +L ≠0 but with B -L =0 . Since the sphaleron processes violate B +L , such GUT-generated asymmetries will finally be washed out completely, making GUT baryogenesis scenarios incapable of reproducing the observed baryon asymmetry of the Universe. In this work, we revisit the idea to revive GUT baryogenesis, proposed by Fukugita and Yanagida, where right-handed neutrinos erase the lepton asymmetry before the sphaleron processes can significantly wash out the original B +L asymmetry, and in this way one can prevent a total washout of the initial baryon asymmetry. By solving the Boltzmann equations numerically for baryon and lepton asymmetries in a simplified 1 +1 flavor scenario, we can confirm the results of the original work. We further generalize the analysis to a more realistic scenario of three active and two right-handed neutrinos to highlight flavor effects of the right-handed neutrinos. Large regions in the parameter space of the Yukawa coupling and the right-handed neutrino mass featuring successful baryogenesis are identified.
Directory of Open Access Journals (Sweden)
Poloni, Marinês Yole
2012-05-01
Full Text Available Este artigo tem por propósito discutir episódios da prática de duas professoras do Ensino Fundamental I que em um curso de formação continuada revisitaram alguns conceitos geométricos. O foco está na reconstrução dos conceitos dessas professoras, entretanto são explicitadas também decisões e estratégias metodológicas por elas tomadas a fim de mediar a aprendizagem dos alunos. A pesquisa de mestrado, que subsidia este texto, foi realizada ao longo do curso “Geometria em Ação”, o qual estava centrado no tema Figuras Planas e, nele, foi utilizado o software Cabri-Géomètre[1]. A fundamentação teórica foi construída a partir dos conceitos de reflexão de Schön, das vertentes do conhecimento didático de Ponte & Oliveira e da articulação entre teoria e prática de Tardif. A pesquisa de caráter qualitativo utilizou a metodologia de Design-Based Research. No artigo apresentamos reflexões tanto sobre a (reconstrução de conceitos geométricos, quanto sobre a prática docente. Concluímos, ao final do estudo, que ocorreram situações de reconstrução de conceitos geométricos por parte de ambas as professoras, particularmente quanto às definições e às propriedades de triângulos e quadriláteros. Em relação à prática docente, elas se conscientizaram das decisões tomadas tanto durante o planejamento de suas aulas quanto durante a aplicação das mesmas avaliando, posteriormente, suas decisões didáticas e pedagógicas. This paper discusses episodes of teaching practices of two primary school teachers whom, during a course of continuing education, have revisited some geometrical concepts. The focus is on the reconstruction of mathematical concepts of these teachers, however, we also present methodological strategies and decisions taken by them in order to support students' learning. The underlying research was carried out along the course "Geometria em Ação" (Geometry in Action, which was centered on the Planar
Revisiting Hansen Solubility Parameters by Including Thermodynamics
Louwerse, Manuel J; Fernández-Maldonado, Ana María; Rousseau, Simon; Moreau-Masselon, Chloe; Roux, Bernard; Rothenberg, Gadi
2017-01-01
The Hansen solubility parameter approach is revisited by implementing the thermodynamics of dissolution and mixing. Hansen's pragmatic approach has earned its spurs in predicting solvents for polymer solutions, but for molecular solutes improvements are needed. By going into the details of entropy
The Future of Engineering Education--Revisited
Wankat, Phillip C.; Bullard, Lisa G.
2016-01-01
This paper revisits the landmark CEE series, "The Future of Engineering Education," published in 2000 (available free in the CEE archives on the internet) to examine the predictions made in the original paper as well as the tools and approaches documented. Most of the advice offered in the original series remains current. Despite new…
Revisiting the formal foundation of Probabilistic Databases
Wanders, B.; van Keulen, Maurice
2015-01-01
One of the core problems in soft computing is dealing with uncertainty in data. In this paper, we revisit the formal foundation of a class of probabilistic databases with the purpose to (1) obtain data model independence, (2) separate metadata on uncertainty and probabilities from the raw data, (3)
Revisiting Weak Simulation for Substochastic Markov Chains
DEFF Research Database (Denmark)
Jansen, David N.; Song, Lei; Zhang, Lijun
2013-01-01
of the logic PCTL\\x, and its completeness was conjectured. We revisit this result and show that soundness does not hold in general, but only for Markov chains without divergence. It is refuted for some systems with substochastic distributions. Moreover, we provide a counterexample to completeness...
Coccolithophorids in polar waters: Wigwamma spp. revisited
DEFF Research Database (Denmark)
Thomsen, Helge Abildhauge; Østergaard, Jette B.; Heldal, Mikal
2013-01-01
A contingent of weakly calcified coccolithophorid genera and species were described from polar regions almost 40 years ago. In the interim period a few additional findings have been reported enlarging the realm of some of the species. The genus Wigwamma is revisited here with the purpose of provi...... appearance of the coccolith armour of the cell...
The Faraday effect revisited: General theory
DEFF Research Database (Denmark)
Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm
2006-01-01
This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. At zero temperature and zero frequency...
The Faraday effect revisited: General theory
DEFF Research Database (Denmark)
Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm
This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse...
eWOM, Revisit Intention, Destination Trust and Gender
Abubakar, Abubakar Mohammed; Ilkan, Mustafa; Al-Tal, Raad Meshall; Eluwole, Kayode
2017-01-01
This article investigates the impact of eWOM on intention to revisit and destination trust, and the moderating role of gender in medical tourism industry. Result from structural equation modeling (n=240) suggests the following: (1) that eWOM influences intention to revisit and destination trust; (2) that destination trust influences intention to revisit; (3) that the impact of eWOM on intention to revisit is about 1.3 times higher in men; (4) that the impact of eWOM on destination trust is ab...
Revisiting Cementoblastoma with a Rare Case Presentation
Directory of Open Access Journals (Sweden)
Vijayanirmala Subramani
2017-01-01
Full Text Available Cementoblastoma is a rare benign odontogenic neoplasm which is characterized by the proliferation of cellular cementum. Diagnosis of cementoblastoma is challenging because of its protracted clinical, radiographic features, and bland histological appearance; most often cementoblastoma is often confused with other cementum and bone originated lesions. The aim of this article is to overview/revisit, approach the diagnosis of cementoblastoma, and also present a unique radiographic appearance of a cementoblastoma lesion associated with an impacted tooth.
Directory of Open Access Journals (Sweden)
Cieślik Andrzej
2015-09-01
Full Text Available In this paper we revisit the existing empirical evidence on the effects of various agglomeration externalities and the market structure on employment growth in the high-tech industries of the European Economic Area (EEA. Our study is based on the dynamic panel dataset of two-digit NACE rev 1.1. industries in 285 regions of the European Economic Area for the period 1995-2007. We find that employment growth is negatively related to competition, while localization and urbanization externalities do not seem to affect growth.
Dynamics of solitons in multicomponent long wave–short wave ...
Indian Academy of Sciences (India)
2Department of Physics, Anna University, Chennai 600 025, India. 3Centre for Nonlinear Dynamics, .... In §3, we revisit the earlier studies on the dynamics of bright multisoliton of ... For this purpose, the power series expansion of variables g(l) ...
Dynamic games theory and applications
Haurie, Alain
2005-01-01
Dynamic games continue to attract strong interest from researchers interested in modeling competitive and conflict situations to study the behavior of players (decision-makers) and to predict the outcome of such situations in many areas including engineering, economics, management science, military, biology, and political science. This collection of articles by established researchers is an excellent reference covering a wide range of emerging and revisited problems in both cooperative and non-cooperative games.
Rational Asset Pricing Bubbles Revisited
Jan Werner
2012-01-01
Price bubble arises when the price of an asset exceeds the asset's fundamental value, that is, the present value of future dividend payments. The important result of Santos and Woodford (1997) says that price bubbles cannot exist in equilibrium in the standard dynamic asset pricing model with rational agents as long as assets are in strictly positive supply and the present value of total future resources is finite. This paper explores the possibility of asset price bubbles when either one of ...
Revisiting the Master-Signifier, or, Mandela and Repression.
Hook, Derek; Vanheule, Stijn
2015-01-01
The concept of the master-signifier has been subject to a variety of applications in Lacanian forms of political discourse theory and ideology critique. While there is much to be commended in literature of this sort, it often neglects salient issues pertaining to the role of master signifiers in the clinical domain of (individual) psychical economy. The popularity of the concept of the master (or "empty") signifier in political discourse analysis has thus proved a double-edged sword. On the one hand it demonstrates how crucial psychical processes are performed via the operations of the signifier, extending thus the Lacanian thesis that identification is the outcome of linguistic and symbolic as opposed to merely psychological processes. On the other, the use of the master signifier concept within the political realm to track discursive formations tends to distance the term from the dynamics of the unconscious and operation of repression. Accordingly, this paper revisits the master signifier concept, and does so within the socio-political domain, yet while paying particular attention to the functioning of unconscious processes of fantasy and repression. More specifically, it investigates how Nelson Mandela operates as a master signifier in contemporary South Africa, as a vital means of knitting together diverse elements of post-apartheid society, enabling the fantasy of the post-apartheid nation, and holding at bay a whole series of repressed and negated undercurrents.
Revisiting the master-signifier, or, Mandela and repression
Directory of Open Access Journals (Sweden)
Derek eHook
2016-01-01
Full Text Available The concept of the master-signifier has been subject to a variety of applications in Lacanian forms of political discourse theory and ideology critique. While there is much to be commended in literature of this sort, it often neglects salient issues pertaining to the role of master signifiers in the clinical domain of (individual psychical economy. The popularity of the concept of the master (or ‘empty’ signifier in political discourse analysis has thus proved a double-edged sword. On the one hand it demonstrates how crucial psychical processes are performed via the operations of the signifier, extending thus the Lacanian thesis that identification is as much the outcome of linguistic and symbolic as opposed to merely psychological processes. On the other, the use of the master signifier concept within the political realm to track discursive formations tends to distance the term from the dynamics of the unconscious and operation of repression. Accordingly, this paper revisits the master signifier concept, and does so within the socio-political domain, yet while paying particular attention to the functioning of unconscious processes of fantasy and repression. More specifically, it investigates how Nelson Mandela operates as a master signifier in contemporary South Africa, as a vital means of knitting together diverse elements of post-apartheid society, enabling the fantasy of the post-apartheid nation, and holding at bay a whole series of repressed and negated undercurrents.
Advanced Change Theory Revisited: An Article Critique
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R. Scott Pochron
2008-12-01
Full Text Available The complexity of life in 21st century society requires new models for leading and managing change. With that in mind, this paper revisits the model for Advanced Change Theory (ACT as presented by Quinn, Spreitzer, and Brown in their article, “Changing Others Through Changing Ourselves: The Transformation of Human Systems” (2000. The authors present ACT as a potential model for facilitating change in complex organizations. This paper presents a critique of the article and summarizes opportunities for further exploring the model in the light of current trends in developmental and integral theory.
Resolution of Reflection Seismic Data Revisited
DEFF Research Database (Denmark)
Hansen, Thomas Mejer; Mosegaard, Klaus; Zunino, Andrea
The Rayleigh Principle states that the minimum separation between two reflectors that allows them to be visually separated is the separation where the wavelet maxima from the two superimposed reflections combine into one maximum. This happens around Δtres = λb/8, where λb is the predominant...... lower vertical resolution of reflection seismic data. In the following we will revisit think layer model and demonstrate that there is in practice no limit to the vertical resolution using the parameterization of Widess (1973), and that the vertical resolution is limited by the noise in the data...
Revisiting fifth forces in the Galileon model
Energy Technology Data Exchange (ETDEWEB)
Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie; Seery, David [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy
2010-05-15
A Galileon field is one which obeys a spacetime generalization of the non- relativistic Galilean invariance. Such a field may possess non-canonical kinetic terms, but ghost-free theories with a well-defined Cauchy problem exist, constructed using a finite number of relevant operators. The interactions of this scalar with matter are hidden by the Vainshtein effect, causing the Galileon to become weakly coupled near heavy sources. We revisit estimates of the fifth force mediated by a Galileon field, and show that the parameters of the model are less constrained by experiment than previously supposed. (orig.)
Large J expansion in ABJM theory revisited.
Dimov, H; Mladenov, S; Rashkov, R C
Recently there has been progress in the computation of the anomalous dimensions of gauge theory operators at strong coupling by making use of the AdS/CFT correspondence. On the string theory side they are given by dispersion relations in the semiclassical regime. We revisit the problem of a large-charge expansion of the dispersion relations for simple semiclassical strings in an [Formula: see text] background. We present the calculation of the corresponding anomalous dimensions of the gauge theory operators to an arbitrary order using three different methods. Although the results of the three methods look different, power series expansions show their consistency.
Sloan Digital Sky Survey Photometric Calibration Revisited
International Nuclear Information System (INIS)
Marriner, John
2012-01-01
The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.
Revisiting the Political Economy of Communication
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Nicholas Garnham
2014-02-01
The task of the paper and the seminar was to revisit some of Nicholas Garnham’s ideas, writings and contributions to the study of the Political Economy of Communication and to reflect on the concepts, history, current status and perspectives of this field and the broader study of political economy today. The topics covered include Raymond Williams’ cultural materialism, Pierre Bourdieu’s sociology of culture, the debate between Political Economy and Cultural Studies, information society theory, Karl Marx’s theory and the critique of capitalism.
Sloan Digital Sky Survey Photometric Calibration Revisited
Energy Technology Data Exchange (ETDEWEB)
Marriner, John; /Fermilab
2012-06-29
The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.
Filter-extruded liposomes revisited
DEFF Research Database (Denmark)
Hinna, Askell; Steiniger, Frank; Hupfeld, Stefan
2016-01-01
(pore-size, number of filter passages, and flow-rate), flow field-flow fractionation in conjunction with multi-angle laser light scattering (AF4-MALLS, Wyatt Technology Corp., Santa Barbara, CA) was employed. Liposome size-distributions determined by AF4-MALLS were compared with those of dynamic light...... is suggested to prepare large (300 nm) liposomes with rather narrow size distribution, based on the filter extrusion at defined flow-rates in combination with freeze-/ thaw-cycling and bench-top centrifugation....
Energy Technology Data Exchange (ETDEWEB)
Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel and The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Evnin, Oleg [California Institute of Technology 452-48, Pasadena, CA 91125 (United States); Nakamura, Shin [Physics Department, Hanyang University, Seoul, 133-791 (Korea, Republic of)
2006-12-15
One-loop string scattering amplitudes computed using the standard D0-brane conformal field theory (CFT) suffer from infrared divergences associated with recoil. A systematic framework to take recoil into account is the worldline formalism, where fixed boundary conditions are replaced by dynamical D0-brane worldlines. We show that, in the worldline formalism, the divergences that plague the CFT are automatically cancelled in a non-trivial way. The amplitudes derived in the worldline formalism can be reproduced by deforming the CFT with a specific 'recoil operator', which is bilocal and different from the ones previously suggested in the literature.
Cosmic censorship conjecture revisited: covariantly
International Nuclear Information System (INIS)
Hamid, Aymen I M; Goswami, Rituparno; Maharaj, Sunil D
2014-01-01
In this paper we study the dynamics of the trapped region using a frame independent semi-tetrad covariant formalism for general locally rotationally symmetric (LRS) class II spacetimes. We covariantly prove some important geometrical results for the apparent horizon, and state the necessary and sufficient conditions for a singularity to be locally naked. These conditions bring out, for the first time in a quantitative and transparent manner, the importance of the Weyl curvature in deforming and delaying the trapped region during continual gravitational collapse, making the central singularity locally visible. (paper)
Revisiting convergence: A research note.
Clark, Rob
2015-09-01
A number of recent studies show that income inequality is declining between countries. In this research note, I question the significance of this trend by examining the role of initial conditions in producing convergence. An important (but neglected) property of inequality dynamics is the tendency for extreme distributions to become more moderate. When income disparities are large, the subsequent trend is biased toward convergence. Conversely, when initial conditions approach parity, divergence becomes the more likely long-term outcome. I apply this principle to trends in GDP PC across 127 countries during the 1980-2010 period. Using counterfactual analysis, I manipulate the initial level of inequality in GDP PC while holding constant each country's observed growth rate during the sample period. I find that the growth dynamics of GDP PC produce either convergence or divergence based simply on the initial distribution of income. The point of transition occurs at a moderate level of inequality, whether using population weights (Gini=.365) or not (Gini=.377). I conclude that the recent convergence observed in GDP PC is primarily a function of large income gaps between countries and would not have materialized at more moderate levels of initial inequality. By contrast, an examination of the pre-1950 period reveals divergent growth patterns that are not sensitive to initial conditions. Copyright © 2015 Elsevier Inc. All rights reserved.
The Mathematics of Dispatchability Revisited
Morris, Paul
2016-01-01
Dispatchability is an important property for the efficient execution of temporal plans where the temporal constraints are represented as a Simple Temporal Network (STN). It has been shown that every STN may be reformulated as a dispatchable STN, and dispatchability ensures that the temporal constraints need only be satisfied locally during execution. Recently it has also been shown that Simple Temporal Networks with Uncertainty, augmented with wait edges, are Dynamically Controllable provided every projection is dispatchable. Thus, the dispatchability property has both theoretical and practical interest. One thing that hampers further work in this area is the underdeveloped theory. The existing definitions are expressed in terms of algorithms, and are less suitable for mathematical proofs. In this paper, we develop a new formal theory of dispatchability in terms of execution sequences. We exploit this to prove a characterization of dispatchability involving the structural properties of the STN graph. This facilitates the potential application of the theory to uncertainty reasoning.
The evolution of individuality revisited.
Radzvilavicius, Arunas L; Blackstone, Neil W
2018-03-25
Evolutionary theory is formulated in terms of individuals that carry heritable information and are subject to selective pressures. However, individuality itself is a trait that had to evolve - an individual is not an indivisible entity, but a result of evolutionary processes that necessarily begin at the lower level of hierarchical organisation. Traditional approaches to biological individuality focus on cooperation and relatedness within a group, division of labour, policing mechanisms and strong selection at the higher level. Nevertheless, despite considerable theoretical progress in these areas, a full dynamical first-principles account of how new types of individuals arise is missing. To the extent that individuality is an emergent trait, the problem can be approached by recognising the importance of individuating mechanisms that are present from the very beginning of the transition, when only lower-level selection is acting. Here we review some of the most influential theoretical work on the role of individuating mechanisms in these transitions, and demonstrate how a lower-level, bottom-up evolutionary framework can be used to understand biological complexity involved in the origin of cellular life, early eukaryotic evolution, sexual life cycles and multicellular development. Some of these mechanisms inevitably stem from environmental constraints, population structure and ancestral life cycles. Others are unique to specific transitions - features of the natural history and biochemistry that are co-opted into conflict mediation. Identifying mechanisms of individuation that provide a coarse-grained description of the system's evolutionary dynamics is an important step towards understanding how biological complexity and hierarchical organisation evolves. In this way, individuality can be reconceptualised as an approximate model that with varying degrees of precision applies to a wide range of biological systems. © 2018 Cambridge Philosophical Society.
Celtic Stone Dynamics Revisited Using Dry Friction and Rolling Resistance
Directory of Open Access Journals (Sweden)
J. Awrejcewicz
2012-01-01
Full Text Available The integral model of dry friction components is built with assumption of classical Coulomb friction law and with specially developed model of normal stress distribution coupled with rolling resistance for elliptic contact shape. In order to avoid a necessity of numerical integration over the contact area at each the numerical simulation step, few versions of approximate model are developed and then tested numerically. In the numerical experiments the simulation results of the Celtic stone with the friction forces modelled by the use of approximants of different complexity (from no coupling between friction force and torque to the second order Padé approximation are compared to results obtained from model with friction approximated in the form of piecewise polynomial functions (based on the Taylor series with hertzian stress distribution. The coefficients of the corresponding approximate models are found by the use of optimization methods, like as in identification process using the real experiment data.
String dynamics in curved space-time revisited
International Nuclear Information System (INIS)
Marrakchi, A.L.; Singh, L.P.
1989-09-01
The equations of motion of the general background of curved space-time, Einstein's equations, are derived simply by demanding the renormalized energy-momentum tensor of a bosonic string propagating in this background to be traceless. The energy-momentum tensor of such a string is then separable into a holomorphic and an antiholomorphic parts as a consequence of the conformal invariance of the theory regained at the quantum level. (author). 8 refs
Oscillatory Dynamics of Gestalt Perception in Schizophrenia Revisited
Directory of Open Access Journals (Sweden)
Kevin M Spencer
2014-02-01
Full Text Available Background: Abnormalities in γ oscillations (30-100 Hz in the scalp-recorded electroencephalogram (EEG have been proposed to reflect neural circuitry abnormalities in schizophrenia. Oscillations in the γ band are thought to play an important role in visual perception, mediating the binding of visual features into coherent objects. However, there is relatively little evidence to date of deficits in γ-mediated processes associated with Gestalt perception in schizophrenia.Methods: Fourteen healthy control subjects (HC and 17 chronic schizophrenia patients (SZ discriminated between illusory Kanisza Squares and No-Square control stimuli, indicating their judgment with a manual button press. Time-frequency decomposition of the EEG was computed with the Morlet wavelet transform. Time-frequency maps of phase locking factor (PLF values were calculated for stimulus- and response-locked oscillations.Results: HC and SZ did not differ in reaction time, error rate, an early ERP effect associated with Gestalt processing, nor an early visual-evoked γ oscillation. Two response-locked high γ effects had greater PLF for Square than No-Square stimuli in HC, and the reverse pattern in SZ. One of these effects was correlated with thought disorder symptom ratings in SZ.Conclusions: SZ demonstrated abnormalities in γ oscillations associated with the perception of Gestalt objects, while their early visual-evoked γ activity was mostly normal, contrary to previous results. This study supports the hypothesis that high-frequency oscillations are sensitive to aspects of psychosis.
Sub-Chandrasekhar-mass White Dwarf Detonations Revisited
Shen, Ken J.; Kasen, Daniel; Miles, Broxton J.; Townsley, Dean M.
2018-02-01
The detonation of a sub-Chandrasekhar-mass white dwarf (WD) has emerged as one of the most promising Type Ia supernova (SN Ia) progenitor scenarios. Recent studies have suggested that the rapid transfer of a very small amount of helium from one WD to another is sufficient to ignite a helium shell detonation that subsequently triggers a carbon core detonation, yielding a “dynamically driven double-degenerate double-detonation” SN Ia. Because the helium shell that surrounds the core explosion is so minimal, this scenario approaches the limiting case of a bare C/O WD detonation. Motivated by discrepancies in previous literature and by a recent need for detailed nucleosynthetic data, we revisit simulations of naked C/O WD detonations in this paper. We disagree to some extent with the nucleosynthetic results of previous work on sub-Chandrasekhar-mass bare C/O WD detonations; for example, we find that a median-brightness SN Ia is produced by the detonation of a 1.0 {M}ȯ WD instead of a more massive and rarer 1.1 {M}ȯ WD. The neutron-rich nucleosynthesis in our simulations agrees broadly with some observational constraints, although tensions remain with others. There are also discrepancies related to the velocities of the outer ejecta and light curve shapes, but overall our synthetic light curves and spectra are roughly consistent with observations. We are hopeful that future multidimensional simulations will resolve these issues and further bolster the dynamically driven double-degenerate double-detonation scenario’s potential to explain most SNe Ia.
Revisiting directed flow in relativistic heavy-ion collisions from a multiphase transport model
Guo, Chong-Qiang; Zhang, Chun-Jian; Xu, Jun
2017-12-01
We have revisited several interesting questions on how the rapidity-odd directed flow is developed in relativistic 197Au+197Au collisions at √{s_{NN}} = 200 and 39 GeV based on a multiphase transport model. As the partonic phase evolves with time, the slope of the parton directed flow at midrapidity region changes from negative to positive as a result of the later dynamics at 200 GeV, while it remains negative at 39 GeV due to the shorter life time of the partonic phase. The directed flow splitting for various quark species due to their different initial eccentricities is observed at 39 GeV, while the splitting is very small at 200GeV. From a dynamical coalescence algorithm with Wigner functions, we found that the directed flow of hadrons is a result of competition between the coalescence in momentum and coordinate space as well as further modifications by the hadronic rescatterings.
Friction and anchorage loading revisited.
Dholakia, Kartik D
2012-01-01
Contemporary concepts of sliding mechanics explain that friction is inevitable. To overcome this frictional resistance, excess force is required to retract the tooth along the archwire (ie, individual retraction of canines, en masse retraction of anterior teeth), in addition to the amount of force required for tooth movement. The anterior tooth retraction force, in addition to excess force (to overcome friction), produces reciprocal protraction force on molars, thereby leading to increased anchorage loading. However, this traditional concept was challenged in recent literature, which was based on the finite element model, but did not bear correlation to the clinical scenario. This article will reinforce the fact that clinically, friction increases anchorage loading in all three planes of space, considering the fact that tooth movement is a quasistatic process rather than a purely continuous or static one, and that conventional ways of determining the effects of static or dynamic friction on anchorage load cannot be applied to clinical situations (which consist of anatomical resistance units and a complex muscular force system). The article does not aim to quantify friction and its effect on the amount of anchorage load. Rather, a new perspective regarding the role of various additional factors (which is not explained by contemporary concept) that may influence friction and anchorage loading is provided..
Post-Inflationary Gravitino Production Revisited
Ellis, John; Nanopoulos, Dimitri V.; Olive, Keith A.; Peloso, Marco
2016-01-01
We revisit gravitino production following inflation. As a first step, we review the standard calculation of gravitino production in the thermal plasma formed at the end of post-inflationary reheating when the inflaton has completely decayed. Next we consider gravitino production prior to the completion of reheating, assuming that the inflaton decay products thermalize instantaneously while they are still dilute. We then argue that instantaneous thermalization is in general a good approximation, and also show that the contribution of non-thermal gravitino production via the collisions of inflaton decay products prior to thermalization is relatively small. Our final estimate of the gravitino-to-entropy ratio is approximated well by a standard calculation of gravitino production in the post-inflationary thermal plasma assuming total instantaneous decay and thermalization at a time $t \\simeq 1.2/\\Gamma_\\phi$. Finally, in light of our calculations, we consider potential implications of upper limits on the gravitin...
Revisiting R-invariant direct gauge mediation
Energy Technology Data Exchange (ETDEWEB)
Chiang, Cheng-Wei [Center for Mathematics and Theoretical Physics andDepartment of Physics, National Central University,Taoyuan, Taiwan 32001, R.O.C. (China); Institute of Physics, Academia Sinica,Taipei, Taiwan 11529, R.O.C. (China); Physics Division, National Center for Theoretical Sciences,Hsinchu, Taiwan 30013, R.O.C. (China); Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); Harigaya, Keisuke [Department of Physics, University of California,Berkeley, California 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, California 94720 (United States); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Ibe, Masahiro [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Yanagida, Tsutomu T. [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan)
2016-03-21
We revisit a special model of gauge mediated supersymmetry breaking, the “R-invariant direct gauge mediation.” We pay particular attention to whether the model is consistent with the minimal model of the μ-term, i.e., a simple mass term of the Higgs doublets in the superpotential. Although the incompatibility is highlighted in view of the current experimental constraints on the superparticle masses and the observed Higgs boson mass, the minimal μ-term can be consistent with the R-invariant gauge mediation model via a careful choice of model parameters. We derive an upper limit on the gluino mass from the observed Higgs boson mass. We also discuss whether the model can explain the 3σ excess of the Z+jets+E{sub T}{sup miss} events reported by the ATLAS collaboration.
The Faraday effect revisited General theory
Cornean, H D; Pedersen, T G
2005-01-01
This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers of the strength of the magnetic field $B$. Then the linear term in $B$ of this expansion is written down in terms of the zero magnetic field Green function and the zero field current operator. In the periodic case, the linear term in $B$ of the conductivity tensor is expressed in terms of zero magnetic field Bloch functions and energies. No derivatives with respect to the quasimomentum appear and thereby all ambiguities are removed, in contrast to earlier work.
Revisiting instanton corrections to the Konishi multiplet
Energy Technology Data Exchange (ETDEWEB)
Alday, Luis F. [Mathematical Institute, University of Oxford,Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG (United Kingdom); Korchemsky, Gregory P. [Institut de Physique Théorique, Université Paris Saclay, CNRS, CEA,F-91191 Gif-sur-Yvette (France)
2016-12-01
We revisit the calculation of instanton effects in correlation functions in N=4 SYM involving the Konishi operator and operators of twist two. Previous studies revealed that the scaling dimensions and the OPE coefficients of these operators do not receive instanton corrections in the semiclassical approximation. We go beyond this approximation and demonstrate that, while operators belonging to the same N=4 supermultiplet ought to have the same conformal data, the evaluation of quantum instanton corrections for one operator can be mapped into a semiclassical computation for another operator in the same supermultiplet. This observation allows us to compute explicitly the leading instanton correction to the scaling dimension of operators in the Konishi supermultiplet as well as to their structure constants in the OPE of two half-BPS scalar operators. We then use these results, together with crossing symmetry, to determine instanton corrections to scaling dimensions of twist-four operators with large spin.
Revisiting kaon physics in general Z scenario
Directory of Open Access Journals (Sweden)
Motoi Endo
2017-08-01
Full Text Available New physics contributions to the Z penguin are revisited in the light of the recently-reported discrepancy of the direct CP violation in K→ππ. Interference effects between the standard model and new physics contributions to ΔS=2 observables are taken into account. Although the effects are overlooked in the literature, they make experimental bounds significantly severer. It is shown that the new physics contributions must be tuned to enhance B(KL→π0νν¯, if the discrepancy of the direct CP violation is explained with satisfying the experimental constraints. The branching ratio can be as large as 6×10−10 when the contributions are tuned at the 10% level.
Sparse random matrices: The eigenvalue spectrum revisited
International Nuclear Information System (INIS)
Semerjian, Guilhem; Cugliandolo, Leticia F.
2003-08-01
We revisit the derivation of the density of states of sparse random matrices. We derive a recursion relation that allows one to compute the spectrum of the matrix of incidence for finite trees that determines completely the low concentration limit. Using the iterative scheme introduced by Biroli and Monasson [J. Phys. A 32, L255 (1999)] we find an approximate expression for the density of states expected to hold exactly in the opposite limit of large but finite concentration. The combination of the two methods yields a very simple geometric interpretation of the tails of the spectrum. We test the analytic results with numerical simulations and we suggest an indirect numerical method to explore the tails of the spectrum. (author)
Neutrino dark energy. Revisiting the stability issue
Energy Technology Data Exchange (ETDEWEB)
Eggers Bjaelde, O.; Hannestad, S. [Aarhus Univ. (Denmark). Dept. of Physics and Astronomy; Brookfield, A.W. [Sheffield Univ. (United Kingdom). Dept. of Applied Mathematics and Dept. of Physics, Astro-Particle Theory and Cosmology Group; Van de Bruck, C. [Sheffield Univ. (United Kingdom). Dept. of Applied Mathematics, Astro-Particle Theory and Cosmology Group; Mota, D.F. [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik]|[Institute of Theoretical Astrophysics, Oslo (Norway); Schrempp, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Tocchini-Valentini, D. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy
2007-05-15
A coupling between a light scalar field and neutrinos has been widely discussed as a mechanism for linking (time varying) neutrino masses and the present energy density and equation of state of dark energy. However, it has been pointed out that the viability of this scenario in the non-relativistic neutrino regime is threatened by the strong growth of hydrodynamic perturbations associated with a negative adiabatic sound speed squared. In this paper we revisit the stability issue in the framework of linear perturbation theory in a model independent way. The criterion for the stability of a model is translated into a constraint on the scalar-neutrino coupling, which depends on the ratio of the energy densities in neutrinos and cold dark matter. We illustrate our results by providing meaningful examples both for stable and unstable models. (orig.)
Re-visiting the electrophysiology of language.
Obleser, Jonas
2015-09-01
This editorial accompanies a special issue of Brain and Language re-visiting old themes and new leads in the electrophysiology of language. The event-related potential (ERP) as a series of characteristic deflections ("components") over time and their distribution on the scalp has been exploited by speech and language researchers over decades to find support for diverse psycholinguistic models. Fortunately, methodological and statistical advances have allowed human neuroscience to move beyond some of the limitations imposed when looking at the ERP only. Most importantly, we currently witness a refined and refreshed look at "event-related" (in the literal sense) brain activity that relates itself more closely to the actual neurobiology of speech and language processes. It is this imminent change in handling and interpreting electrophysiological data of speech and language experiments that this special issue intends to capture. Copyright © 2015 Elsevier Inc. All rights reserved.
Alignment dynamics of diffusive scalar gradient in a two-dimensional model flow
Gonzalez, M.
2018-04-01
The Lagrangian two-dimensional approach of scalar gradient kinematics is revisited accounting for molecular diffusion. Numerical simulations are performed in an analytic, parameterized model flow, which enables considering different regimes of scalar gradient dynamics. Attention is especially focused on the influence of molecular diffusion on Lagrangian statistical orientations and on the dynamics of scalar gradient alignment.
Revisiting Stock Market Integration Pre-Post Subprime Mortgage Crisis: Insight From BRIC Countries
Directory of Open Access Journals (Sweden)
Chin-Hong Puah
2015-07-01
Full Text Available This study revisits the long-run relationships and short-run dynamic causal linkages among BRIC stock market, with the particular attention to the 2008 subprime mortgage crisis. Extending related empirical studies, comparative analyses of pre-crisis, and post-crisis periods were conducted to comprehensively evaluate how stock market integration was affected by financial crises. In general, after employing cointegration test and VAR test, the results reveal the increase of stock market integration in BRICs after the subprime crisis. The evidence also found that China stock market is the most influential among the BRICs, in which China stock market has the ability to Granger cause the other three BRICs member countries. An important implication of our findings is that the degree of integration among countries tends to change over time, especially around periods marked by financial crises.
Standing and travelling waves in a spherical brain model: The Nunez model revisited
Visser, S.; Nicks, R.; Faugeras, O.; Coombes, S.
2017-06-01
The Nunez model for the generation of electroencephalogram (EEG) signals is naturally described as a neural field model on a sphere with space-dependent delays. For simplicity, dynamical realisations of this model either as a damped wave equation or an integro-differential equation, have typically been studied in idealised one dimensional or planar settings. Here we revisit the original Nunez model to specifically address the role of spherical topology on spatio-temporal pattern generation. We do this using a mixture of Turing instability analysis, symmetric bifurcation theory, centre manifold reduction and direct simulations with a bespoke numerical scheme. In particular we examine standing and travelling wave solutions using normal form computation of primary and secondary bifurcations from a steady state. Interestingly, we observe spatio-temporal patterns which have counterparts seen in the EEG patterns of both epileptic and schizophrenic brain conditions.
Pair Production Constraints on Superluminal Neutrinos Revisited
International Nuclear Information System (INIS)
Brodsky, Stanley
2012-01-01
We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p 2 can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.
Carbon emission from global hydroelectric reservoirs revisited.
Li, Siyue; Zhang, Quanfa
2014-12-01
Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.
Meta-analysis in clinical trials revisited.
DerSimonian, Rebecca; Laird, Nan
2015-11-01
In this paper, we revisit a 1986 article we published in this Journal, Meta-Analysis in Clinical Trials, where we introduced a random-effects model to summarize the evidence about treatment efficacy from a number of related clinical trials. Because of its simplicity and ease of implementation, our approach has been widely used (with more than 12,000 citations to date) and the "DerSimonian and Laird method" is now often referred to as the 'standard approach' or a 'popular' method for meta-analysis in medical and clinical research. The method is especially useful for providing an overall effect estimate and for characterizing the heterogeneity of effects across a series of studies. Here, we review the background that led to the original 1986 article, briefly describe the random-effects approach for meta-analysis, explore its use in various settings and trends over time and recommend a refinement to the method using a robust variance estimator for testing overall effect. We conclude with a discussion of repurposing the method for Big Data meta-analysis and Genome Wide Association Studies for studying the importance of genetic variants in complex diseases. Published by Elsevier Inc.
Critical boundary sine-Gordon revisited
International Nuclear Information System (INIS)
Hasselfield, M.; Lee, Taejin; Semenoff, G.W.; Stamp, P.C.E.
2006-01-01
We revisit the exact solution of the two space-time dimensional quantum field theory of a free massless boson with a periodic boundary interaction and self-dual period. We analyze the model by using a mapping to free fermions with a boundary mass term originally suggested in Ref. [J. Polchinski, L. Thorlacius, Phys. Rev. D 50 (1994) 622]. We find that the entire SL (2, C) family of boundary states of a single boson are boundary sine-Gordon states and we derive a simple explicit expression for the boundary state in fermion variables and as a function of sine-Gordon coupling constants. We use this expression to compute the partition function. We observe that the solution of the model has a strong-weak coupling generalization of T-duality. We then examine a class of recently discovered conformal boundary states for compact bosons with radii which are rational numbers times the self-dual radius. These have simple expression in fermion variables. We postulate sine-Gordon-like field theories with discrete gauge symmetries for which they are the appropriate boundary states
The drive revisited: Mastery and satisfaction.
Denis, Paul
2016-06-01
Starting from the theory of the libido and the notions of the experience of satisfaction and the drive for mastery introduced by Freud, the author revisits the notion of the drive by proposing the following model: the drive takes shape in the combination of two currents of libidinal cathexis, one which takes the paths of the 'apparatus for obtaining mastery' (the sense-organs, motricity, etc.) and strives to appropriate the object, and the other which cathects the erotogenic zones and the experience of satisfaction that is experienced through stimulation in contact with the object. The result of this combination of cathexes constitutes a 'representation', the subsequent evocation of which makes it possible to tolerate for a certain period of time the absence of a satisfying object. On the basis of this conception, the author distinguishes the representations proper, vehicles of satisfaction, from imagos and traumatic images which give rise to excitation that does not link up with the paths taken by the drives. This model makes it possible to conciliate the points of view of the advocates of 'object-seeking' and of those who give precedence to the search for pleasure, and, further, to renew our understanding of object-relations, which can then be approached from the angle of their relations to infantile sexuality. Destructiveness is considered in terms of "mastery madness" and not in terms of the late Freudian hypothesis of the death drive. Copyright © 2015 Institute of Psychoanalysis.
Revisiting the argument from fetal potential
Directory of Open Access Journals (Sweden)
Manninen Bertha
2007-05-01
Full Text Available Abstract One of the most famous, and most derided, arguments against the morality of abortion is the argument from potential, which maintains that the fetus' potential to become a person and enjoy the valuable life common to persons, entails that its destruction is prima facie morally impermissible. In this paper, I will revisit and offer a defense of the argument from potential. First, I will criticize the classical arguments proffered against the importance of fetal potential, specifically the arguments put forth by philosophers Peter Singer and David Boonin, by carefully unpacking the claims made in these arguments and illustrating why they are flawed. Secondly, I will maintain that fetal potential is morally relevant when it comes to the morality of abortion, but that it must be accorded a proper place in the argument. This proper place, however, cannot be found until we first answer a very important and complex question: we must first address the issue of personal identity, and when the fetus becomes the type of being who is relevantly identical to a future person. I will illustrate why the question of fetal potential can only be meaningfully addressed after we have first answered the question of personal identity and how it relates to the human fetus.
THE CONCEPT OF REFERENCE CONDITION, REVISITED ...
Ecological assessments of aquatic ecosystems depend on the ability to compare current conditions against some expectation of how they could be in the absence of significant human disturbance. The concept of a ‘‘reference condition’’ is often used to describe the standard or benchmark against which current condition is compared. If assessments are to be conducted consistently, then a common understanding of the definitions and complications of reference condition is necessary. A 2006 paper (Stoddard et al., 2006, Ecological Applications 16:1267-1276) made an early attempt at codifying the reference condition concept; in this presentation we will revisit the points raised in that paper (and others) and examine how our thinking has changed in a little over 10 years.Among the issues to be discussed: (1) the “moving target” created when reference site data are used to set thresholds in large scale assessments; (2) natural vs. human disturbance and their effects on reference site distributions; (3) circularity and the use of biological data to assist in reference site identification; (4) using site-scale (in-stream or in-lake) measurements vs. landscape-level human activity to identify reference conditions. Ecological assessments of aquatic ecosystems depend on the ability to compare current conditions against some expectation of how they could be in the absence of significant human disturbance. The concept of a ‘‘reference condition’’ is often use
Ellis, John
2016-01-01
We revisit minimal supersymmetric SU(5) grand unification (GUT) models in which the soft supersymmetry-breaking parameters of the minimal supersymmetric Standard Model (MSSM) are universal at some input scale, $M_{in}$, above the supersymmetric gauge coupling unification scale, $M_{GUT}$. As in the constrained MSSM (CMSSM), we assume that the scalar masses and gaugino masses have common values, $m_0$ and $m_{1/2}$ respectively, at $M_{in}$, as do the trilinear soft supersymmetry-breaking parameters $A_0$. Going beyond previous studies of such a super-GUT CMSSM scenario, we explore the constraints imposed by the lower limit on the proton lifetime and the LHC measurement of the Higgs mass, $m_h$. We find regions of $m_0$, $m_{1/2}$, $A_0$ and the parameters of the SU(5) superpotential that are compatible with these and other phenomenological constraints such as the density of cold dark matter, which we assume to be provided by the lightest neutralino. Typically, these allowed regions appear for $m_0$ and $m_{1/...
Energy Technology Data Exchange (ETDEWEB)
P., Henry
2008-11-20
A recent article in which John Searle claims to refute dualism is examined from a scientific perspective. John Searle begins his recent article 'Dualism Revisited' by stating his belief that the philosophical problem of consciousness has a scientific solution. He then claims to refute dualism. It is therefore appropriate to examine his arguments against dualism from a scientific perspective. Scientific physical theories contain two kinds of descriptions: (1) Descriptions of our empirical findings, expressed in an every-day language that allows us communicate to each other our sensory experiences pertaining to what we have done and what we have learned; and (2) Descriptions of a theoretical model, expressed in a mathematical language that allows us to communicate to each other certain ideas that exist in our mathematical imaginations, and that are believed to represent, within our streams of consciousness, certain aspects of reality that we deem to exist independently of their being perceived by any human observer. These two parts of our scientific description correspond to the two aspects of our general contemporary dualistic understanding of the total reality in which we are imbedded, namely the empirical-mental aspect and the theoretical-physical aspect. The duality question is whether this general dualistic understanding of ourselves should be regarded as false in some important philosophical or scientific sense.
Post-inflationary gravitino production revisited
Energy Technology Data Exchange (ETDEWEB)
Ellis, John [Theoretical Particle Physics and Cosmology Group, Department of Physics, King' s College London, London WC2R 2LS (United Kingdom); Garcia, Marcos A.G.; Olive, Keith A. [William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Nanopoulos, Dimitri V. [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Peloso, Marco, E-mail: john.ellis@cern.ch, E-mail: garciagarcia@physics.umn.edu, E-mail: dimitri@physics.tamu.edu, E-mail: olive@physics.umn.edu, E-mail: peloso@physics.umn.edu [School of Physics and Astronomy and Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)
2016-03-01
We revisit gravitino production following inflation. As a first step, we review the standard calculation of gravitino production in the thermal plasma formed at the end of post-inflationary reheating when the inflaton has completely decayed. Next we consider gravitino production prior to the completion of reheating, assuming that the inflaton decay products thermalize instantaneously while they are still dilute. We then argue that instantaneous thermalization is in general a good approximation, and also show that the contribution of non-thermal gravitino production via the collisions of inflaton decay products prior to thermalization is relatively small. Our final estimate of the gravitino-to-entropy ratio is approximated well by a standard calculation of gravitino production in the post-inflationary thermal plasma assuming total instantaneous decay and thermalization at a time t ≅ 1.2/Γ{sub φ}. Finally, in light of our calculations, we consider potential implications of upper limits on the gravitino abundance for models of inflation, with particular attention to scenarios for inflaton decays in supersymmetric Starobinsky-like models.
Pipe failure probability - the Thomas paper revisited
International Nuclear Information System (INIS)
Lydell, B.O.Y.
2000-01-01
Almost twenty years ago, in Volume 2 of Reliability Engineering (the predecessor of Reliability Engineering and System Safety), a paper by H. M. Thomas of Rolls Royce and Associates Ltd. presented a generalized approach to the estimation of piping and vessel failure probability. The 'Thomas-approach' used insights from actual failure statistics to calculate the probability of leakage and conditional probability of rupture given leakage. It was intended for practitioners without access to data on the service experience with piping and piping system components. This article revisits the Thomas paper by drawing on insights from development of a new database on piping failures in commercial nuclear power plants worldwide (SKI-PIPE). Partially sponsored by the Swedish Nuclear Power Inspectorate (SKI), the R and D leading up to this note was performed during 1994-1999. Motivated by data requirements of reliability analysis and probabilistic safety assessment (PSA), the new database supports statistical analysis of piping failure data. Against the background of this database development program, the article reviews the applicability of the 'Thomas approach' in applied risk and reliability analysis. It addresses the question whether a new and expanded database on the service experience with piping systems would alter the original piping reliability correlation as suggested by H. M. Thomas
Revisit to diffraction anomalous fine structure
International Nuclear Information System (INIS)
Kawaguchi, T.; Fukuda, K.; Tokuda, K.; Shimada, K.; Ichitsubo, T.; Oishi, M.; Mizuki, J.; Matsubara, E.
2014-01-01
The diffraction anomalous fine structure method has been revisited by applying this measurement technique to polycrystalline samples and using an analytical method with the logarithmic dispersion relation. The diffraction anomalous fine structure (DAFS) method that is a spectroscopic analysis combined with resonant X-ray diffraction enables the determination of the valence state and local structure of a selected element at a specific crystalline site and/or phase. This method has been improved by using a polycrystalline sample, channel-cut monochromator optics with an undulator synchrotron radiation source, an area detector and direct determination of resonant terms with a logarithmic dispersion relation. This study makes the DAFS method more convenient and saves a large amount of measurement time in comparison with the conventional DAFS method with a single crystal. The improved DAFS method has been applied to some model samples, Ni foil and Fe 3 O 4 powder, to demonstrate the validity of the measurement and the analysis of the present DAFS method
Revisiting the Survival Mnemonic Effect in Children
Directory of Open Access Journals (Sweden)
Josefa N. S. Pand Eirada
2014-04-01
Full Text Available The survival processing paradigm is designed to explore the adaptive nature of memory functioning. The mnemonic advantage of processing information in fitness-relevant contexts, as has been demonstrated using this paradigm, is now well established, particularly in young adults; this phenomenon is often referred to as the “survival processing effect.” In the current experiment, we revisited the investigation of this effect in children and tested it in a new cultural group, using a procedure that differs from the existing studies with children. A group of 40 Portuguese children rated the relevance of unrelated words to a survival and a new moving scenario. This encoding task was followed by a surprise free-recall task. Akin to what is typically found, survival processing produced better memory performance than the control condition (moving. These data put on firmer ground the idea that a mnemonic tuning to fitness-relevant encodings is present early in development. The theoretical importance of this result to the adaptive memory literature is discussed, as well as potential practical implications of this kind of approach to the study of memory in children.
Pockets of Participation: Revisiting Child-Centred Participation Research
Franks, Myfanwy
2011-01-01
This article revisits the theme of the clash of interests and power relations at work in participatory research which is prescribed from above. It offers a possible route toward solving conflict between adult-led research carried out by young researchers, funding requirements and organisational constraints. The article explores issues of…
Literary Origins of the Term "School Psychologist" Revisited
Fagan, Thomas K.
2005-01-01
Previous research on the literary origins of the term "school psychologist" is revisited, and conclusions are revised in light of new evidence. It appears that the origin of the term in the American literature occurred as early as 1898 in an article by Hugo Munsterberg, predating the usage by Wilhelm Stern in 1911. The early references to the…
The Neutrosophic Logic View to Schrodinger's Cat Paradox, Revisited
Directory of Open Access Journals (Sweden)
Florentin Smarandache
2008-07-01
Full Text Available The present article discusses Neutrosophic logic view to Schrodinger's cat paradox. We argue that this paradox involves some degree of indeterminacy (unknown which Neutrosophic logic can take into consideration, whereas other methods including Fuzzy logic cannot. To make this proposition clear, we revisit our previous paper by offering an illustration using modified coin tossing problem, known as Parrondo's game.
Revisiting Constructivist Teaching Methods in Ontario Colleges Preparing for Accreditation
Schultz, Rachel A.
2015-01-01
At the time of writing, the first community colleges in Ontario were preparing for transition to an accreditation model from an audit system. This paper revisits constructivist literature, arguing that a more pragmatic definition of constructivism effectively blends positivist and interactionist philosophies to achieve both student centred…
High precision mass measurements in Ψ and Υ families revisited
International Nuclear Information System (INIS)
Artamonov, A.S.; Baru, S.E.; Blinov, A.E.
2000-01-01
High precision mass measurements in Ψ and Υ families performed in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the J/Ψ(1S) and Ψ(2S) mass measurements [ru
The Importance of Being a Complement: CED Effects Revisited
Jurka, Johannes
2010-01-01
This dissertation revisits subject island effects (Ross 1967, Chomsky 1973) cross-linguistically. Controlled acceptability judgment studies in German, English, Japanese and Serbian show that extraction out of specifiers is consistently degraded compared to extraction out of complements, indicating that the Condition on Extraction domains (CED,…
Surface tension in soap films: revisiting a classic demonstration
International Nuclear Information System (INIS)
Behroozi, F
2010-01-01
We revisit a classic demonstration for surface tension in soap films and introduce a more striking variation of it. The demonstration shows how the film, pulling uniformly and normally on a loose string, transforms it into a circular arc under tension. The relationship between the surface tension and the string tension is analysed and presented in a useful graphical form. (letters and comments)
Additively homomorphic encryption with a double decryption mechanism, revisited
Peter, Andreas; Kronberg, M.; Trei, W.; Katzenbeisser, S.
We revisit the notion of additively homomorphic encryption with a double decryption mechanism (DD-PKE), which allows for additions in the encrypted domain while having a master decryption procedure that can decrypt all properly formed ciphertexts by using a special master secret. This type of
Revisiting Jack Goody to Rethink Determinisms in Literacy Studies
Collin, Ross
2013-01-01
This article revisits Goody's arguments about literacy's influence on social arrangements, culture, cognition, economics, and other domains of existence. Whereas some of his arguments tend toward technological determinism (i.e., literacy causes change in the world), other of his arguments construe literacy as a force that shapes and is shaped by…
Surface tension in soap films: revisiting a classic demonstration
Energy Technology Data Exchange (ETDEWEB)
Behroozi, F [Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614 (United States)], E-mail: behroozi@uni.edu
2010-01-15
We revisit a classic demonstration for surface tension in soap films and introduce a more striking variation of it. The demonstration shows how the film, pulling uniformly and normally on a loose string, transforms it into a circular arc under tension. The relationship between the surface tension and the string tension is analysed and presented in a useful graphical form. (letters and comments)
A control center design revisited: learning from users’ appropriation
DEFF Research Database (Denmark)
Souza da Conceição, Carolina; Cordeiro, Cláudia
2014-01-01
This paper aims to present the lessons learned during a control center design project by revisiting another control center from the same company designed two and a half years before by the same project team. In light of the experience with the first project and its analysis, the designers and res...
A Feminist Revisit to the First-Year Curriculum.
Bernstein, Anita
1996-01-01
A seminar at Chicago-Kent College of Law (Illinois) that reviews six first-year law school courses by focusing on feminist issues in course content and structure is described. The seminar functions as both a review and a shift in perspective. Courses revisited include civil procedure, contracts, criminal law, justice and the legal system,…
Moral Judgment Development across Cultures: Revisiting Kohlberg's Universality Claims
Gibbs, John C.; Basinger, Karen S.; Grime, Rebecca L.; Snarey, John R.
2007-01-01
This article revisits Kohlberg's cognitive developmental claims that stages of moral judgment, facilitative processes of social perspective-taking, and moral values are commonly identifiable across cultures. Snarey [Snarey, J. (1985). "The cross-cultural universality of social-moral development: A critical review of Kohlbergian research."…
Revisiting the quantum harmonic oscillator via unilateral Fourier transforms
International Nuclear Information System (INIS)
Nogueira, Pedro H F; Castro, Antonio S de
2016-01-01
The literature on the exponential Fourier approach to the one-dimensional quantum harmonic oscillator problem is revised and criticized. It is shown that the solution of this problem has been built on faulty premises. The problem is revisited via the Fourier sine and cosine transform method and the stationary states are properly determined by requiring definite parity and square-integrable eigenfunctions. (paper)
Transport benchmarks for one-dimensional binary Markovian mixtures revisited
International Nuclear Information System (INIS)
Malvagi, F.
2013-01-01
The classic benchmarks for transport through a binary Markovian mixture are revisited to look at the probability distribution function of the chosen 'results': reflection, transmission and scalar flux. We argue that the knowledge of the ensemble averaged results is not sufficient for reliable predictions: a measure of the dispersion must also be obtained. An algorithm to estimate this dispersion is tested. (author)
Thorbecke Revisited : The Role of Doctrinaire Liberalism in Dutch Politics
Drentje, Jan
2011-01-01
Thorbecke Revisited: The Role of Doctrinaire Liberalism in Dutch Politics In the political history of the nineteenth century Thorbecke played a crucial role. As the architect of the 1848 liberal constitutional reform he led three cabinets. In many ways he dominated the political discourse during the
Faraday effect revisited: sum rules and convergence issues
DEFF Research Database (Denmark)
Cornean, Horia; Nenciu, Gheorghe
2010-01-01
This is the third paper of a series revisiting the Faraday effect. The question of the absolute convergence of the sums over the band indices entering the Verdet constant is considered. In general, sum rules and traces per unit volume play an important role in solid-state physics, and they give...
Who should do the dishes now? Revisiting gender and housework in contemporary urban South Wales
Mannay, Dawn
2016-01-01
This chapter revisits Jane Pilcher’s (1994) seminal work ‘Who should do the dishes? Three generations of Welsh women talking about men and housework’, which was originally published in Our Sister’s Land: the changing identities of women in Wales. As discussed in the introductory chapter, I began revisiting classic Welsh studies as part of my doctoral study Mothers and daughters on the margins: gender, generation and education (Mannay, 2012); this lead to the later publication of a revisiting ...
A Structural Equation Model of Risk Perception of Rockfall for Revisit Intention
Ya-Fen Lee; Yun-Yao Chi
2014-01-01
The study aims to explore the relationship between risk perception of rockfall and revisit intention using a Structural Equation Modeling (SEM) analysis. A total of 573 valid questionnaires are collected from travelers to Taroko National Park, Taiwan. The findings show the majority of travelers have the medium perception of rockfall risk, and are willing to revisit the Taroko National Park. The revisit intention to Taroko National Park is influenced by hazardous preferences, willingness-to-pa...
Directory of Open Access Journals (Sweden)
Nikola Dedić
2013-06-01
Full Text Available The main aim of this text is to show parallels between rock music and poststructuralist philosophy. As a case study one of the most celebrated rock albums of all times – Bob Dylan’s Highway 61 Revisited from 1965 is taken. It is one of the crucial albums in the history of popular culture which influenced further development of rock music within American counter culture of the 60s. Dylan’s turn from the politics of American New Left and folk movement, his relation towards the notions of the author and intertextuality, and his connection with experimental usage of language in the manner of avant-garde and neoavant-garde poetry, are juxtaposed with the main philosophical standpoints of Jean-François Lyotard, Jean Baudrillard, Roland Barthes and Julia Kristeva which historically and chronologically coincide with the appearance of Dylan’s album.
The coordinate coherent states approach revisited
International Nuclear Information System (INIS)
Miao, Yan-Gang; Zhang, Shao-Jun
2013-01-01
We revisit the coordinate coherent states approach through two different quantization procedures in the quantum field theory on the noncommutative Minkowski plane. The first procedure, which is based on the normal commutation relation between an annihilation and creation operators, deduces that a point mass can be described by a Gaussian function instead of the usual Dirac delta function. However, we argue this specific quantization by adopting the canonical one (based on the canonical commutation relation between a field and its conjugate momentum) and show that a point mass should still be described by the Dirac delta function, which implies that the concept of point particles is still valid when we deal with the noncommutativity by following the coordinate coherent states approach. In order to investigate the dependence on quantization procedures, we apply the two quantization procedures to the Unruh effect and Hawking radiation and find that they give rise to significantly different results. Under the first quantization procedure, the Unruh temperature and Unruh spectrum are not deformed by noncommutativity, but the Hawking temperature is deformed by noncommutativity while the radiation specturm is untack. However, under the second quantization procedure, the Unruh temperature and Hawking temperature are untack but the both spectra are modified by an effective greybody (deformed) factor. - Highlights: ► Suggest a canonical quantization in the coordinate coherent states approach. ► Prove the validity of the concept of point particles. ► Apply the canonical quantization to the Unruh effect and Hawking radiation. ► Find no deformations in the Unruh temperature and Hawking temperature. ► Provide the modified spectra of the Unruh effect and Hawking radiation.
Backwardation in energy futures markets: Metalgesellschaft revisited
International Nuclear Information System (INIS)
Charupat, N.; Deaves, R.
2003-01-01
Energy supply contracts negotiated by the US Subsidiary of Metalgesellschaft Refining and Marketing (MGRM), which were the subject of much subsequent debate, are re-examined. The contracts were hedged by the US Subsidiary barrel-for-barrel using short-dated energy derivatives. When the hedge program experienced difficulties, the derivatives positions were promptly liquidated by the parent company. Revisiting the MGRM contracts also provides the opportunity to explore the latest evidence on backwardation in energy markets. Accordingly, the paper discusses first the theoretical reasons for backwardation, followed by an empirical examination using the MGRM data available at the time of the hedge program in 1992 and a second set of data that became available in 2000. By using a more up-to-date data set covering a longer time period and by controlling the time series properties of the data, the authors expect to provide more reliable empirical evidence on the behaviour of energy futures prices. Results based on the 1992 data suggest that the strategy employed by MGRM could be expected to be profitable while the risks are relatively low. However, analysis based on the 2000 data shows lower, although still significant profits, but higher risks. The final conclusion was that the likelihood of problems similar to those faced by MGRM in 1992 are twice as high with the updated 2000 data, suggesting that the risk-return pattern of the stack-and-roll hedging strategy using short-dated energy future contracts to hedge long-tem contracts is less appealing now than when MGRM implemented its hedging program in 1992. 24 refs., 3 tabs., 6 figs
Clifford Algebra Implying Three Fermion Generations Revisited
International Nuclear Information System (INIS)
Krolikowski, W.
2002-01-01
The author's idea of algebraic compositeness of fundamental particles, allowing to understand the existence in Nature of three fermion generations, is revisited. It is based on two postulates. Primo, for all fundamental particles of matter the Dirac square-root procedure √p 2 → Γ (N) ·p works, leading to a sequence N=1, 2, 3, ... of Dirac-type equations, where four Dirac-type matrices Γ (N) μ are embedded into a Clifford algebra via a Jacobi definition introducing four ''centre-of-mass'' and (N - 1) x four ''relative'' Dirac-type matrices. These define one ''centre-of-mass'' and N - 1 ''relative'' Dirac bispinor indices. Secundo, the ''centre-of-mass'' Dirac bispinor index is coupled to the Standard Model gauge fields, while N - 1 ''relative'' Dirac bispinor indices are all free indistinguishable physical objects obeying Fermi statistics along with the Pauli principle which requires the full antisymmetry with respect to ''relative'' Dirac indices. This allows only for three Dirac-type equations with N = 1, 3, 5 in the case of N odd, and two with N = 2, 4 in the case of N even. The first of these results implies unavoidably the existence of three and only three generations of fundamental fermions, namely leptons and quarks, as labelled by the Standard Model signature. At the end, a comment is added on the possible shape of Dirac 3 x 3 mass matrices for four sorts of spin-1/2 fundamental fermions appearing in three generations. For charged leptons a prediction is m τ = 1776.80 MeV, when the input of experimental m e and m μ is used. (author)
Solar system anomalies: Revisiting Hubble's law
Plamondon, R.
2017-12-01
This paper investigates the impact of a new metric recently published [R. Plamondon and C. Ouellet-Plamondon, in On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories, edited by K. Rosquist, R. T. Jantzen, and R. Ruffini (World Scientific, Singapore, 2015), p. 1301] for studying the space-time geometry of a static symmetric massive object. This metric depends on a complementary error function (erfc) potential that characterizes the emergent gravitation field predicted by the model. This results in two types of deviations as compared to computations made on the basis of a Newtonian potential: a constant and a radial outcome. One key feature of the metric is that it postulates the existence of an intrinsic physical constant σ , the massive object-specific proper length that scales measurements in its surroundings. Although σ must be evaluated experimentally, we use a heuristic to estimate its value and point out some latent relationships between the Hubble constant, the secular increase in the astronomical unit, and the Pioneers delay. Indeed, highlighting the systematic errors that emerge when the effect of σ is neglected, one can link the Hubble constant H 0 to σ Sun and the secular increase V AU to σ Earth . The accuracy of the resulting numerical predictions, H 0 = 74 . 42 ( 0 . 02 ) ( km / s ) / Mpc and V AU ≅ 7.8 cm yr-1 , calls for more investigations of this new metric by specific experts. Moreover, we investigate the expected impacts of the new metric on the flyby anomalies, and we revisit the Pioneers delay. It is shown that both phenomena could be partly taken into account within the context of this unifying paradigm, with quite accurate numerical predictions. A correction for the osculating asymptotic velocity at the perigee of the order of 10 mm/s and an inward radial acceleration of 8 . 34 × 10 - 10 m / s 2 affecting the Pioneer ! space crafts could be explained by this new model.
Double neutron stars: merger rates revisited
Chruslinska, Martyna; Belczynski, Krzysztof; Klencki, Jakub; Benacquista, Matthew
2018-03-01
We revisit double neutron star (DNS) formation in the classical binary evolution scenario in light of the recent Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo DNS detection (GW170817). The observationally estimated Galactic DNS merger rate of R_MW = 21^{+28}_{-14} Myr-1, based on three Galactic DNS systems, fully supports our standard input physics model with RMW = 24 Myr-1. This estimate for the Galaxy translates in a non-trivial way (due to cosmological evolution of progenitor stars in chemically evolving Universe) into a local (z ≈ 0) DNS merger rate density of Rlocal = 48 Gpc-3 yr-1, which is not consistent with the current LIGO/Virgo DNS merger rate estimate (1540^{+3200}_{-1220} Gpc-3 yr-1). Within our study of the parameter space, we find solutions that allow for DNS merger rates as high as R_local ≈ 600^{+600}_{-300} Gpc-3 yr-1 which are thus consistent with the LIGO/Virgo estimate. However, our corresponding BH-BH merger rates for the models with high DNS merger rates exceed the current LIGO/Virgo estimate of local BH-BH merger rate (12-213 Gpc-3 yr-1). Apart from being particularly sensitive to the common envelope treatment, DNS merger rates are rather robust against variations of several of the key factors probed in our study (e.g. mass transfer, angular momentum loss, and natal kicks). This might suggest that either common envelope development/survival works differently for DNS (˜10-20 M⊙ stars) than for BH-BH (˜40-100 M⊙ stars) progenitors, or high black hole (BH) natal kicks are needed to meet observational constraints for both types of binaries. Our conclusion is based on a limited number of (21) evolutionary models and is valid within this particular DNS and BH-BH isolated binary formation scenario.
Clifford Algebra Implying Three Fermion Generations Revisited
Krolikowski, Wojciech
2002-09-01
The author's idea of algebraic compositeness of fundamental particles, allowing to understand the existence in Nature of three fermion generations, is revisited. It is based on two postulates. Primo, for all fundamental particles of matter the Dirac square-root procedure √ {p2} → {Γ }(N)p works, leading to a sequence N = 1,2,3, ... of Dirac-type equations, where four Dirac-type matrices {Γ }(N)μ are embedded into a Clifford algebra via a Jacobi definition introducing four ``centre-of-mass'' and (N-1)× four ``relative'' Dirac-type matrices. These define one ``centre-of-mass'' and (N-1) ``relative'' Dirac bispinor indices. Secundo, the ``centre-of-mass'' Dirac bispinor index is coupled to the Standard Model gauge fields, while (N-1) ``relative'' Dirac bispinor indices are all free indistinguishable physical objects obeying Fermi statistics along with the Pauli principle which requires the full antisymmetry with respect to ``relative'' Dirac indices. This allows only for three Dirac-type equations with N = 1,3,5 in the case of N odd, and two with N = 2,4 in the case of N even. The first of these results implies unavoidably the existence of three and only three generations of fundamental fermions, namely leptons and quarks, as labelled by the Standard Model signature. At the end, a comment is added on the possible shape of Dirac 3x3 mass matrices for four sorts of spin-1/2 fundamental fermions appearing in three generations. For charged leptons a prediction is mτ = 1776.80 MeV, when the input of experimental me and mμ is used.
REVISITING SCALING RELATIONS FOR GIANT RADIO HALOS IN GALAXY CLUSTERS
Energy Technology Data Exchange (ETDEWEB)
Cassano, R.; Brunetti, G.; Venturi, T.; Kale, R. [INAF/IRA, via Gobetti 101, I-40129 Bologna (Italy); Ettori, S. [INAF/Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Pratt, G. W. [Laboratoire AIM, IRFU/Service dAstrophysique-CEA/DSM-CNRS-Université Paris Diderot, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Dolag, K. [University Observatory Munich, Scheinerstr. 1, D-81679 Munich (Germany); Markevitch, M. [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
2013-11-10
Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R{sub 500} as P{sub 1.4}∼L{sup 2.1±0.2}{sub 500}. Our bigger and more homogenous sample confirms that the X-ray luminous (L{sub 500} > 5 × 10{sup 44} erg s{sup –1}) clusters branch into two populations—radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P{sub 1.4} scales with the cluster integrated SZ signal within R{sub 500}, measured by Planck, as P{sub 1.4}∼Y{sup 2.05±0.28}{sub 500}, in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that 'SZ-luminous' Y{sub 500} > 6 × 10{sup –5} Mpc{sup 2} clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the
Wibowo, Setyo Ferry; Sazali, Adnan; Kresnamurti R. P., Agung
2016-01-01
The purpose of this research are: 1) To find out the description of destination image, tourist satisfaction, and revisit intention of Betawi cultural village Setu Babakan, 2) test empirically the influence of destination image toward revisit intention of Betawi cultural village Setu Babakan, 3) test empirically the influence of tourist satisfaction toward revisit intention of Betawi cultural village Setu Babakan, 4) test empirically the influence of destination image toward revisit intention ...
The timeline of the lunar bombardment: Revisited
Morbidelli, A.; Nesvorny, D.; Laurenz, V.; Marchi, S.; Rubie, D. C.; Elkins-Tanton, L.; Wieczorek, M.; Jacobson, S.
2018-05-01
The timeline of the lunar bombardment in the first Gy of Solar System history remains unclear. Basin-forming impacts (e.g. Imbrium, Orientale), occurred 3.9-3.7 Gy ago, i.e. 600-800 My after the formation of the Moon itself. Many other basins formed before Imbrium, but their exact ages are not precisely known. There is an intense debate between two possible interpretations of the data: in the cataclysm scenario there was a surge in the impact rate approximately at the time of Imbrium formation, while in the accretion tail scenario the lunar bombardment declined since the era of planet formation and the latest basins formed in its tail-end. Here, we revisit the work of Morbidelli et al. (2012) that examined which scenario could be compatible with both the lunar crater record in the 3-4 Gy period and the abundance of highly siderophile elements (HSE) in the lunar mantle. We use updated numerical simulations of the fluxes of asteroids, comets and planetesimals leftover from the planet-formation process. Under the traditional assumption that the HSEs track the total amount of material accreted by the Moon since its formation, we conclude that only the cataclysm scenario can explain the data. The cataclysm should have started ∼ 3.95 Gy ago. However we also consider the possibility that HSEs are sequestered from the mantle of a planet during magma ocean crystallization, due to iron sulfide exsolution (O'Neil, 1991; Rubie et al., 2016). We show that this is likely true also for the Moon, if mantle overturn is taken into account. Based on the hypothesis that the lunar magma ocean crystallized about 100-150 My after Moon formation (Elkins-Tanton et al., 2011), and therefore that HSEs accumulated in the lunar mantle only after this timespan, we show that the bombardment in the 3-4 Gy period can be explained in the accretion tail scenario. This hypothesis would also explain why the Moon appears so depleted in HSEs relative to the Earth. We also extend our analysis of the
Revisit ocean thermal energy conversion system
International Nuclear Information System (INIS)
Huang, J.C.; Krock, H.J.; Oney, S.K.
2003-01-01
by-products, especially drinking water, aquaculture and mariculture, can easily translate into billions of dollars in business opportunities. The current status of the OTEC system definitely deserves to be carefully revisited. This paper will examine recent major advancements in technology, evaluate costs and effectiveness, and assess the overall market environment of the OTEC system and describe its great renewable energy potential and overall benefits to the nations of the world
The significance test controversy revisited the fiducial Bayesian alternative
Lecoutre, Bruno
2014-01-01
The purpose of this book is not only to revisit the “significance test controversy,”but also to provide a conceptually sounder alternative. As such, it presents a Bayesian framework for a new approach to analyzing and interpreting experimental data. It also prepares students and researchers for reporting on experimental results. Normative aspects: The main views of statistical tests are revisited and the philosophies of Fisher, Neyman-Pearson and Jeffrey are discussed in detail. Descriptive aspects: The misuses of Null Hypothesis Significance Tests are reconsidered in light of Jeffreys’ Bayesian conceptions concerning the role of statistical inference in experimental investigations. Prescriptive aspects: The current effect size and confidence interval reporting practices are presented and seriously questioned. Methodological aspects are carefully discussed and fiducial Bayesian methods are proposed as a more suitable alternative for reporting on experimental results. In closing, basic routine procedures...
The hard-core model on random graphs revisited
International Nuclear Information System (INIS)
Barbier, Jean; Krzakala, Florent; Zhang, Pan; Zdeborová, Lenka
2013-01-01
We revisit the classical hard-core model, also known as independent set and dual to vertex cover problem, where one puts particles with a first-neighbor hard-core repulsion on the vertices of a random graph. Although the case of random graphs with small and very large average degrees respectively are quite well understood, they yield qualitatively different results and our aim here is to reconciliate these two cases. We revisit results that can be obtained using the (heuristic) cavity method and show that it provides a closed-form conjecture for the exact density of the densest packing on random regular graphs with degree K ≥ 20, and that for K > 16 the nature of the phase transition is the same as for large K. This also shows that the hard-code model is the simplest mean-field lattice model for structural glasses and jamming
Radiative corrections to neutrino deep inelastic scattering revisited
International Nuclear Information System (INIS)
Arbuzov, Andrej B.; Bardin, Dmitry Yu.; Kalinovskaya, Lidia V.
2005-01-01
Radiative corrections to neutrino deep inelastic scattering are revisited. One-loop electroweak corrections are re-calculated within the automatic SANC system. Terms with mass singularities are treated including higher order leading logarithmic corrections. Scheme dependence of corrections due to weak interactions is investigated. The results are implemented into the data analysis of the NOMAD experiment. The present theoretical accuracy in description of the process is discussed
The Assassination of John F. Kennedy: Revisiting the Medical Data
Rohrich, Rod J.; Nagarkar, Purushottam; Stokes, Mike; Weinstein, Aaron; Mantik, David W.; Jensen, J. Arthur
2014-01-01
Thank you for publishing "The Assassination of John F. Kennedy: Revisiting the Medical Data."1 The central conclusion of this study is that the assassination remains controversial and that some of the controversy must be attributable to the "reporting and handling of the medical evidence." With the greatest respect for you and Dr. Robert McClelland, let me argue that your text and on-line interviews perpetuate the central misunderstanding of the assassination and there...
Quark matter revisited with non-extensive MIT bag model
Energy Technology Data Exchange (ETDEWEB)
Cardoso, Pedro H.G.; Nunes da Silva, Tiago; Menezes, Debora P. [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, Florianopolis (Brazil); Deppman, Airton [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)
2017-10-15
In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed. (orig.)
Ambulatory thyroidectomy: A multistate study of revisits and complications
Orosco, RK; Lin, HW; Bhattacharyya, N
2015-01-01
© 2015 American Academy of Otolaryngology - Head and Neck Surgery Foundation. Objective. Determine rates and reasons for revisits after ambulatory adult thyroidectomy. Study Design. Cross-sectional analysis of multistate ambulatory surgery and hospital databases. Setting. Ambulatory surgery data from the State Ambulatory Surgery Databases of California, Florida, Iowa, and New York for calendar years 2010 and 2011. Subjects and Methods. Ambulatory thyroidectomy cases were linked to state ambul...
Place attachment and social legitimacy: Revisiting the sustainable entrepreneurship journey
Kibler, E; Fink, M; Lang, R; Munoz, PA
2015-01-01
This paper revisits the sustainable entrepreneurship journey by introducing a ‘place- based’ sustainable venture path model. We suggest that distinguishing between emo- tional (‘caring about the place’) and instrumental (‘using the place’) place attachment of sustainable entrepreneurs deepens our understanding of how place-based challenges of sustainable venture legitimacy are managed over time. We conclude with avenues for future sustainable entrepreneurship research.
Doppler Processing with Ultra-Wideband (UWB) Radar Revisited
2018-01-01
REPORT TYPE Technical Note 3. DATES COVERED (From - To) December 2017 4. TITLE AND SUBTITLE Doppler Processing with Ultra-Wideband (UWB) Radar...unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT This technical note revisits previous work performed at the US Army Research Laboratory related to...target considered previously is proportional to a delayed version of the transmitted signal, up to a complex constant factor. We write the received
Radiative corrections to double-Dalitz decays revisited
Kampf, Karol; Novotný, Jiři; Sanchez-Puertas, Pablo
2018-03-01
In this study, we revisit and complete the full next-to-leading order corrections to pseudoscalar double-Dalitz decays within the soft-photon approximation. Comparing to the previous study, we find small differences, which are nevertheless relevant for extracting information about the pseudoscalar transition form factors. Concerning the latter, these processes could offer the opportunity to test them—for the first time—in their double-virtual regime.
Dispute Resolution and Technology: Revisiting the Justification of Conflict Management
Koulu, Riikka
2016-01-01
This study, Dispute Resolution and Technology: Revisiting the Justification of Conflict Management, belongs to the fields of procedural law, legal theory and law and technology studies. In this study the changes in dispute resolution caused by technology are evaluated. The overarching research question of this study is how does implementing technology to dispute resolution challenge the justification of law as a legitimised mode of violence? Before answering such an abstract research question...
Deja vu: The Unified Command Plan of the Future Revisited
2011-05-19
Approved for Public Release; Distribution is Unlimited Déjà vu : The Unified Command Plan of the Future Revisited A Monograph by Lieutenant...DD-MM-YYYY) 19-05-2011 2. REPORT TYPE Monograph 3. DATES COVERED (From - To) JUL 2010 – MAY 2011 4. TITLE AND SUBTITLE Déjà vu : The Unified...i SCHOOL OF ADVANCED MILITARY STUDIES MONOGRAPH APPROVAL Lieutenant Colonel Edward Francis Martignetti Title of Monograph: Déjà vu : The Unified
Hospital revisit rate after a diagnosis of conversion disorder.
Merkler, Alexander E; Parikh, Neal S; Chaudhry, Simriti; Chait, Alanna; Allen, Nicole C; Navi, Babak B; Kamel, Hooman
2016-04-01
To estimate the hospital revisit rate of patients diagnosed with conversion disorder (CD). Using administrative data, we identified all patients discharged from California, Florida and New York emergency departments (EDs) and acute care hospitals between 2005 and 2011 with a primary discharge diagnosis of CD. Patients discharged with a primary diagnosis of seizure or transient global amnesia (TGA) served as control groups. Our primary outcome was the rate of repeat ED visits and hospital admissions after initial presentation. Poisson regression was used to compare rates between diagnosis groups while adjusting for demographic characteristics. We identified 7946 patients discharged with a primary diagnosis of CD. During a mean follow-up of 3.0 (±1.6) years, patients with CD had a median of three (IQR, 1-9) ED or inpatient revisits, compared with 0 (IQR, 0-2) in patients with TGA and 3 (IQR, 1-7) in those with seizures. Revisit rates were 18.25 (95% CI, 18.10 to 18.40) visits per 100 patients per month in those with CD, 3.90 (95% CI, 3.84 to 3.95) in those with TGA and 17.78 (95% CI, 17.75 to 17.81) in those with seizures. As compared to CD, the incidence rate ratio for repeat ED visits or hospitalisations was 0.89 (95% CI, 0.86 to 0.93) for seizure disorder and 0.32 (95% CI 0.31 to 0.34) for TGA. CD is associated with a substantial hospital revisit rate. Our findings suggest that CD is not an acute, time-limited response to stress, but rather that CD is a manifestation of a broader pattern of chronic neuropsychiatric disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited
DEFF Research Database (Denmark)
Martens, Pernille; Worm, Signe Westring; Lundgren, Bettina
2004-01-01
Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited.Martens P, Worm SW, Lundgren B, Konradsen HB, Benfield T. Department of Infectious Diseases 144, Hvidovre University Hospital, DK-2650 Hvidovre, Denmark. pernillemartens@yahoo.com BACKGROUND: Invasive infection...... with Streptococcus pneumoniae (pneumococci) causes significant morbidity and mortality. Case series and experimental data have shown that the capsular serotype is involved in the pathogenesis and a determinant of disease outcome. METHODS: Retrospective review of 464 cases of invasive disease among adults diagnosed...
Revisiting directed flow in relativistic heavy-ion collisions from a multiphase transport model
Energy Technology Data Exchange (ETDEWEB)
Guo, Chong-Qiang; Zhang, Chun-Jian [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China); University of Chinese Academy of Sciences, Beijing (China); Xu, Jun [Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Shanghai (China)
2017-12-15
We have revisited several interesting questions on how the rapidity-odd directed flow is developed in relativistic {sup 197}Au + {sup 197}Au collisions at √(s{sub NN}) = 200 and 39 GeV based on a multiphase transport model. As the partonic phase evolves with time, the slope of the parton directed flow at midrapidity region changes from negative to positive as a result of the later dynamics at 200 GeV, while it remains negative at 39 GeV due to the shorter life time of the partonic phase. The directed flow splitting for various quark species due to their different initial eccentricities is observed at 39 GeV, while the splitting is very small at 200 GeV. From a dynamical coalescence algorithm with Wigner functions, we found that the directed flow of hadrons is a result of competition between the coalescence in momentum and coordinate space as well as further modifications by the hadronic rescatterings. (orig.)
Directory of Open Access Journals (Sweden)
Siavash Zokaeieh
2018-05-01
Full Text Available Postmethod pedagogy and critical pedagogy have influential roles in education and language teaching. A number of practitioners may claim to instruct based on the tenets of postmethod pedagogy, however, they may not be entirely aware of the oppositional intention and dynamicity of this model. This article aims at revisiting the tenets and constructing elements of critical pedagogy and Freire’s point of view vis-a-vis postmethod pedagogy and Kumaravadivelu’s developed model to enlighten the open-mindedness and dynamic perceptions of these interwoven approaches. Furthermore, some criticisms towards critical pedagogy and postmethod pedagogy are brought into consideration for better understanding of the relevance and the weaknesses. It is hoped that by bringing these two notions, teachers especially those who wish to use postmethod pedagogy in their setting become more aware of the intellectual priorities of critical pedagogy and postmethod pedagogy such as moving from banking model of education, absence of bias and deviation from predetermined and fixed frameworks in the classrooms.
International Nuclear Information System (INIS)
Fullagar, Wilfred K.; Paganin, David M.; Hall, Chris J.
2011-01-01
Transient optical gratings for detecting ultrafast signals are routine for temporally resolved photochemical investigations. Many processes can contribute to the formation of such gratings; we indicate use of optically scattering centres that can be formed with highly variable latencies in different materials and devices using ionising radiation. Coherent light scattered by these centres can form the short-wavelength-to-optical-wavelength, incoherent-to-coherent basis of a Bragg X-ray microscope, with inherent scope for optical phasing. Depending on the dynamics of the medium chosen, the way is open to both ultrafast pulsed and integrating measurements. For experiments employing brief pulses, we discuss high-dynamic-range short-wavelength diffraction measurements with real-time optical reconstructions. Applications to optical real-time X-ray phase-retrieval are considered. -- Research highlights: → It is timely that the concept of Bragg's X-ray microscope be revisited. → Transient gratings can be used for X-ray all-optical information processing. → Applications to optical real-time X-ray phase-retrieval are considered.
Galileo-invariant theory of low energy pion-nucleus scattering
International Nuclear Information System (INIS)
Mach, R.
1980-01-01
Two classes of Galileo-invariant optical models are constructed for pion elastic scattering by nuclei. The first, the two-body model, has been obtained assuming that the pion-bound nucleon dynamics is determined by the pion-nucleon kinetic energy. In deriving the second model, the (A+1)-body dynamics has been taken into account. The technique of effective nucleon momenta maintains the nonlocal propagation of the pion-target nucleon subsystem through the nucleus in contrast with the standard static approximation
Galileo-invariant theory of low energy pion-nucleus scattering. II
International Nuclear Information System (INIS)
Mach, R.
1983-01-01
Two classes of Galileo-invariant optical models are constructed for pion elastic scattering by nuclei. The former, the two-body model, was obtained assuming that the pion-bound nucleon dynamics is determined by the pion-nucleon kinetic energy. In deriving the latter model, the (A+1)-body dynamics was taken into account. The technique of effective nucleon momenta maintains the nonlocal propagation of the pion-target nucleon subsystem through the nucleus in contrast with the standard static approximation. (author)
Non-pionic effects in deuteron asymptotic observables
International Nuclear Information System (INIS)
Ballot, J.L.; Robilotta, M.R.
1991-01-01
It is well known that pion dynamics dominates deuteron asymptotic observables, especially η, the D/S ratio and Q, the quadrupole moment. A procedure has been discussed earlier that allows the unambiguous determination of the pion contribution to these observables as function of the pion-nucleon coupling constant. This problem is discussed in the framework of a specific model for the nucleon-nucleon interaction, namely the potential developed by the Tourreil, Rouben and Sprung. The contribution of non-pionic dynamics to deuteron asymptotic observables is investigated. It is shown that effects due to ρ and ω exchanges are negligible. (K.A.) 8 refs., 1 fig., 1 tab
Darwin model in plasma physics revisited
International Nuclear Information System (INIS)
Xie, Huasheng; Zhu, Jia; Ma, Zhiwei
2014-01-01
Dispersion relations from the Darwin (a.k.a., magnetoinductive or magnetostatic) model are given and compared with those of the full electromagnetic model. Analytical and numerical solutions show that the errors from the Darwin approximation can be large even if phase velocity for a low-frequency wave is close to or larger than the speed of light. Besides missing two wave branches associated mainly with the electron dynamics, the coupling branch of the electrons and ions in the Darwin model is modified to become a new artificial branch that incorrectly represents the coupling dynamics of the electrons and ions. (paper)
Revisiting the Gulf Coast after Katrina
Principal, 2009
2009-01-01
In August 2005, the world witnessed one of the most destructive natural disasters on America's mainland. Hurricane Katrina, followed a month later by Hurricane Rita, brought more than broken levees, flooded streets and homes, and destroyed businesses. It caused changes in the dynamics and the demographic and cultural makeup of the region. One of…
Reproduction in the yellow mongoose revisited
African Journals Online (AJOL)
1991-03-12
Mar 12, 1991 ... studies on known females provide clear evidence of the production of two litters annually within a period of .... suckling stimulus does not appear to result in a long-term inhibition .... Population dynamics and food habits of the.
Predictors and Outcomes of Revisits in Older Adults Discharged from the Emergency Department.
de Gelder, Jelle; Lucke, Jacinta A; de Groot, Bas; Fogteloo, Anne J; Anten, Sander; Heringhaus, Christian; Dekkers, Olaf M; Blauw, Gerard J; Mooijaart, Simon P
2018-04-01
To study predictors of emergency department (ED) revisits and the association between ED revisits and 90-day functional decline or mortality. Multicenter cohort study. One academic and two regional Dutch hospitals. Older adults discharged from the ED (N=1,093). At baseline, data on demographic characteristics, illness severity, and geriatric parameters (cognition, functional capacity) were collected. All participants were prospectively followed for an unplanned revisit within 30 days and for functional decline and mortality 90 days after the initial visit. The median age was 79 (interquartile range 74-84), and 114 participants (10.4%) had an ED revisit within 30 days of discharge. Age (hazard ratio (HR)=0.96, 95% confidence interval (CI)=0.92-0.99), male sex (HR=1.61, 95% CI=1.05-2.45), polypharmacy (HR=2.06, 95% CI=1.34-3.16), and cognitive impairment (HR=1.71, 95% CI=1.02-2.88) were independent predictors of a 30-day ED revisit. The area under the receiver operating characteristic curve to predict an ED revisit was 0.65 (95% CI=0.60-0.70). In a propensity score-matched analysis, individuals with an ED revisit were at higher risk (odds ratio=1.99 95% CI=1.06-3.71) of functional decline or mortality. Age, male sex, polypharmacy, and cognitive impairment were independent predictors of a 30-day ED revisit, but no useful clinical prediction model could be developed. However, an early ED revisit is a strong new predictor of adverse outcomes in older adults. © 2018 The Authors. The Journal of the American Geriatrics Society published by Wiley Periodicals, Inc. on behalf of The American Geriatrics Society.
Circular revisit orbits design for responsive mission over a single target
Li, Taibo; Xiang, Junhua; Wang, Zhaokui; Zhang, Yulin
2016-10-01
The responsive orbits play a key role in addressing the mission of Operationally Responsive Space (ORS) because of their capabilities. These capabilities are usually focused on supporting specific targets as opposed to providing global coverage. One subtype of responsive orbits is repeat coverage orbit which is nearly circular in most remote sensing applications. This paper deals with a special kind of repeating ground track orbit, referred to as circular revisit orbit. Different from traditional repeat coverage orbits, a satellite on circular revisit orbit can visit a target site at both the ascending and descending stages in one revisit cycle. This typology of trajectory allows a halving of the traditional revisit time and does a favor to get useful information for responsive applications. However the previous reported numerical methods in some references often cost lots of computation or fail to obtain such orbits. To overcome this difficulty, an analytical method to determine the existence conditions of the solutions to revisit orbits is presented in this paper. To this end, the mathematical model of circular revisit orbit is established under the central gravity model and the J2 perturbation. A constraint function of the circular revisit orbit is introduced, and the monotonicity of that function has been studied. The existent conditions and the number of such orbits are naturally worked out. Taking the launch cost into consideration, optimal design model of circular revisit orbit is established to achieve a best orbit which visits a target twice a day in the morning and in the afternoon respectively for several days. The result shows that it is effective to apply circular revisit orbits in responsive application such as reconnoiter of natural disaster.
Behavioral Objectives and Standards Movement Revisited
Directory of Open Access Journals (Sweden)
Nima Shakouri
2014-02-01
Full Text Available The present paper sparks a complementary argument that the development of standards movement must not be at the expense of sacrificing the achievement of behavioral objectives. Furthermore, due to the systemic and dynamic nature of standards, standards need to be revised off and on. Besides, the present writers taking a more or less relativist stance maintains that if and only if the goal of education is to change one's behavior, the behavioral objectives seem to be plausible; however, it is less than a realistic wish because classroom as a dynamic setting cannot be accomplished within the framework of feed-forward planning, where ends are classified before means are selected.
A practical method of predicting client revisit intention in a hospital setting.
Lee, Kyun Jick
2005-01-01
Data mining (DM) models are an alternative to traditional statistical methods for examining whether higher customer satisfaction leads to higher revisit intention. This study used a total of 906 outpatients' satisfaction data collected from a nationwide survey interviews conducted by professional interviewers on a face-to-face basis in South Korea, 1998. Analyses showed that the relationship between overall satisfaction with hospital services and outpatients' revisit intention, along with word-of-mouth recommendation as intermediate variables, developed into a nonlinear relationship. The five strongest predictors of revisit intention were overall satisfaction, intention to recommend to others, awareness of hospital promotion, satisfaction with physician's kindness, and satisfaction with treatment level.
Electron and pion interactions with nuclei. Progress report, August 1, 1983-August 1, 1984
International Nuclear Information System (INIS)
McCarthy, J.S.
1984-01-01
The experimental program has been based upon the selective use of electron and pion probes to investigate fundamental aspects of nuclear structure. The experiments on electron accelerators span the region from low energy (<100 MeV) high resolution work to the region of electron energy where the fundamental description of the nucleus must be changed. The emphasis in the electron experiments is to understand the basic N-N force, in particular the short range behavior of this force and its effect on nuclear properties. The pion reactions have concentrated on the few body system in an attempt to understand the basic pion-nucleon dynamics
'The Ethiopian famine' revisited: band aid and the antipolitics of celebrity humanitarian action.
Müller, Tanja R
2013-01-01
In many ways the Ethiopian famine of 1983-85 has served as a watershed with respect to humanitarian action. One of its lasting legacies has been the emergence of Band Aid and the subsequent increase in celebrity humanitarianism. A revisiting of the events of 1983-85 occurred in 2010 during a dispute in which it was alleged that a portion of the donations of Band Aid were spent on arms purchases. This paper takes this controversy as its starting point. It goes on to use the theoretical reflections of Giorgio Agamben to consider the dynamics that unfolded during the Ethiopian famine of 1983-85 and to analyse the underlying conceptualisation behind the emergence of Band Aid-type celebrity humanitarianism. The paper concludes with some wider thoughts on how the in essence antipolitical agenda of celebrity humanitarian action is transported into the everyday understanding of 'African disaster', resulting ultimately in the perpetuation of hegemonic control by the global North. © 2013 The Author(s). Journal compilation © Overseas Development Institute, 2013.
Mo, Qifeng; Li, Zhi'An; Zhu, Weixing; Zou, Bi; Li, Yingwen; Yu, Shiqin; Ding, Yongzhen; Chen, Yao; Li, Xiaobo; Wang, Faming
2016-01-01
Nitrogen availability and tree species selection play important roles in reforestation. However, long-term field studies on the effects and mechanisms of tree species composition on N transformation are very limited. Eight years after tree seedlings were planted in a field experiment, we revisited the site and tested how tree species composition affects the dynamics of N mineralization and nitrification. Both tree species composition and season significantly influenced the soil dissolved organic carbon (DOC) and nitrogen (DON). N-fixing Acacia crassicarpa monoculture had the highest DON, and 10-mixed species plantation had the highest DOC. The lowest DOC and DON concentrations were both observed in Eucalyptus urophylla monoculture. The tree species composition also significantly affected net N mineralization rates. The highest rate of net N mineralization was found in A. crassicarpa monoculture, which was over twice than that in Castanopsis hystrix monoculture. The annual net N mineralization rates of 10-mixed and 30-mixed plantations were similar as that of N-fixing monoculture. Since mixed plantations have good performance in increasing soil DOC, DON, N mineralization and plant biodiversity, we recommend that mixed species plantations should be used as a sustainable approach for the restoration of degraded land in southern China.
Revisiting the Lissajous figure as a tool to study bistable perception.
Weilnhammer, V A; Ludwig, K; Sterzer, P; Hesselmann, G
2014-05-01
During bistable vision perception spontaneously "switches" between two mutually exclusive percepts despite constant sensory input. The endogenous nature of these perceptual transitions has motivated extensive research aimed at the underlying mechanisms, since spontaneous perceptual transitions of bistable stimuli should in principle allow for a dissociation of processes related to sensory stimulation from those related to conscious perception. However, transitions from one conscious percept to another are often not instantaneous, and participants usually report a considerable amount of mixed or unclear percepts. This feature of bistable vision makes it difficult to isolate transition-related visual processes. Here, we revisited an ambiguous depth-from-motion stimulus which was first introduced to experimental psychology more than 80 years ago. This rotating Lissajous figure might prove useful in complementing other bistable stimuli, since its perceptual transitions only occur at critical stimulus configurations and are virtually instantaneous, thus facilitating the construction of a perceptually equivalent replay condition. We found that three parameters of the Lissajous figure - complexity, line width, and rotational speed - differentially modulated its perceptual dominance durations and transition probabilities, thus providing experimenters with a versatile tool to study the perceptual dynamics of bistable vision. Copyright © 2014 Elsevier B.V. All rights reserved.
Noise processing by microRNA-mediated circuits: The Incoherent Feed-Forward Loop, revisited
Directory of Open Access Journals (Sweden)
Silvia Grigolon
2016-04-01
Full Text Available The intrinsic stochasticity of gene expression is usually mitigated in higher eukaryotes by post-transcriptional regulation channels that stabilise the output layer, most notably protein levels. The discovery of small non-coding RNAs (miRNAs in specific motifs of the genetic regulatory network has led to identifying noise buffering as the possible key function they exert in regulation. Recent in vitro and in silico studies have corroborated this hypothesis. It is however also known that miRNA-mediated noise reduction is hampered by transcriptional bursting in simple topologies. Here, using stochastic simulations validated by analytical calculations based on van Kampen's expansion, we revisit the noise-buffering capacity of the miRNA-mediated Incoherent Feed Forward Loop (IFFL, a small module that is widespread in the gene regulatory networks of higher eukaryotes, in order to account for the effects of intermittency in the transcriptional activity of the modulator gene. We show that bursting considerably alters the circuit's ability to control static protein noise. By comparing with other regulatory architectures, we find that direct transcriptional regulation significantly outperforms the IFFL in a broad range of kinetic parameters. This suggests that, under pulsatile inputs, static noise reduction may be less important than dynamical aspects of noise and information processing in characterising the performance of regulatory elements.
Revisiting the “Secret Consort” (gsang yum in Tibetan Buddhism
Directory of Open Access Journals (Sweden)
Holly Gayley
2018-06-01
Full Text Available This article revisits the question, first introduced by feminist scholars in the mid-1990s, about whether sexual practices within Buddhist tantra (heterosexually conceived are empowering or exploitative to women. The purpose here is to complicate this question, given the different geographic settings and cultural contexts in which consort relationships have been embedded—from eastern Tibet to North America—and to nuance our understanding of the potential and pitfalls of sexuality in tantric contexts. To do so, I query the dynamics of secrecy and sexuality in tantric practice, examining twentieth century examples of female practitioners of Tibetan Buddhism who have participated in such relationships and thereby highlighting the localized ways that the “secret consort” (gsang yum has been invoked as a social role. This issue is especially relevant today in light of the global #MeToo movement and recent disclosures of sexual improprieties and alleged abuse involving Tibetan teachers at the head of Buddhist communities in Europe and North America. For this reason, to conclude, I discuss shifting perspectives on sexuality as Buddhist tantra has spread beyond Asia and draw attention to current voices calling for greater transparency and community accountability.
Revisiting The First Galaxies: The effects of Population III stars on their host galaxies
Energy Technology Data Exchange (ETDEWEB)
Muratov, Alexander L. [U. Michigan, Dept. Astron.; Gnedin, Oleg Y. [U. Michigan, Dept. Astron.; Gnedin, Nickolay Y. [Chicago U., Astron. Astrophys. Ctr.; Zemp, Marcel [Beijing, KITPC
2013-07-12
We revisit the formation and evolution of the first galaxies using new hydrodynamic cosmological simulations with the adaptive refinement tree code. Our simulations feature a recently developed model for H_{2} formation and dissociation, and a star formation recipe that is based on molecular rather than atomic gas. Here, we develop and implement a recipe for the formation of metal-free Population III (Pop III) stars in galaxy-scale simulations that resolve primordial clouds with sufficiently high density. We base our recipe on the results of prior zoom-in simulations that resolved the protostellar collapse in pre-galactic objects. We find the epoch during which Pop III stars dominated the energy and metal budget of the first galaxies to be short-lived. Galaxies that host Pop III stars do not retain dynamical signatures of their thermal and radiative feedback for more than 10^{8} years after the lives of the stars end in pair-instability supernovae, even when we consider the maximum reasonable efficiency of the feedback. Though metals ejected by the supernovae can travel well beyond the virial radius of the host galaxy, they typically begin to fall back quickly, and do not enrich a large fraction of the intergalactic medium. Galaxies with a total mass in excess of 3 × 10^{6} M_{⊙} re-accrete most of their baryons and transition to metal-enriched Pop II star formation.
REVISITING A CLASSIC: THE PARKER–MOFFATT PROBLEM
International Nuclear Information System (INIS)
Pezzi, O.; Servidio, S.; Valentini, F.; Malara, F.; Veltri, P.; Parashar, T. N.; Yang, Y.; Matthaeus, W. H.; Vásconez, C. L.
2017-01-01
The interaction of two colliding Alfvén wave packets is described here by means of magnetohydrodynamics (MHD) and hybrid kinetic numerical simulations. The MHD evolution revisits the theoretical insights described by Moffatt, Parker, Kraichnan, Chandrasekhar, and Elsässer in which the oppositely propagating large-amplitude wave packets interact for a finite time, initiating turbulence. However, the extension to include compressive and kinetic effects, while maintaining the gross characteristics of the simpler classic formulation, also reveals intriguing features that go beyond the pure MHD treatment.
Revisiting the level scheme of the proton emitter 151Lu
International Nuclear Information System (INIS)
Wang, F.; Sun, B.H.; Liu, Z.; Scholey, C.; Eeckhaudt, S.; Grahn, T.; Greenlees, P.T.; Jones, P.; Julin, R.; Juutinen, S.; Kettelhut, S.; Leino, M.; Nyman, M.; Rahkila, P.; Saren, J.; Sorri, J.; Uusitalo, J.; Ashley, S.F.; Cullen, I.J.; Garnsworthy, A.B.; Gelletly, W.; Jones, G.A.; Pietri, S.; Podolyak, Z.; Steer, S.; Thompson, N.J.; Walker, P.M.; Williams, S.; Bianco, L.; Darby, I.G.; Joss, D.T.; Page, R.D.; Pakarinen, J.; Rigby, S.; Cullen, D.M.; Khan, S.; Kishada, A.; Gomez-Hornillos, M.B.; Simpson, J.; Jenkins, D.G.; Niikura, M.; Seweryniak, D.; Shizuma, Toshiyuki
2015-01-01
An experiment aiming to search for new isomers in the region of proton emitter 151 Lu was performed at the Accelerator Laboratory of the University of Jyväskylä (JYFL), by combining the high resolution γ-ray array JUROGAM, gas-filled RITU separator and GREAT detectors with the triggerless total data readout acquisition (TDR) system. In this proceeding, we revisit the level scheme of 151 Lu by using the proton-tagging technique. A level scheme consistent with the latest experimental results is obtained, and 3 additional levels are identified at high excitation energies. (author)
The role of brand destination experience in determining revisit intention
DEFF Research Database (Denmark)
Mattsson, Jan; Barnes, Stuart; Sørensen, Flemming
Destination branding has developed considerably as a topic area in the last decade with numerous conceptualizations focusing on different aspects of the brand. However, a unified view has not yet emerged. This paper examines destination branding via a new conceptualization, brand destination...... experience, which provides a more holistic and unified view of the brand destination. The research uses a logistic regression model to determine the role of satisfaction and brand experience in determining revisit intentions. The study also examines differences among subgroups and four brand experience sub...
Article Review: Advanced Change Theory Revisited: An Article Critique
Directory of Open Access Journals (Sweden)
R. Scott Pochron
2008-12-01
Full Text Available The complexity of life in 21st century society requires new models for leadingand managing change. With that in mind, this paper revisits the model for AdvancedChange Theory (ACT as presented by Quinn, Spreitzer, and Brown in their article,“Changing Others Through Changing Ourselves: The Transformation of HumanSystems” (2000. The authors present ACT as a potential model for facilitating change incomplex organizations. This paper presents a critique of the article and summarizesopportunities for further exploring the model in the light of current trends indevelopmental and integral theory.
Rural-Nonrural Disparities in Postsecondary Educational Attainment Revisited
Byun, Soo-yong; Meece, Judith L.; Irvin, Matthew J.
2013-01-01
Using data from the National Educational Longitudinal Study, this study revisited rural-nonrural disparities in educational attainment by considering a comprehensive set of factors that constrain and support youth's college enrollment and degree completion. Results showed that rural students were more advantaged in community social resources compared to nonrural students, and these resources were associated with a significant increase in the likelihood of bachelor's degree attainment. Yet results confirmed that rural students lagged behind nonrural students in attaining a bachelor's degree largely due to their lower socioeconomic background. The findings present a more comprehensive picture of the complexity of geographic residence in shaping college enrollment and degree attainment. PMID:24285873
Revisited neoclassical transport theory for steep, collisional plasma edge profiles
International Nuclear Information System (INIS)
Rogister, A.L.
1994-01-01
Published neoclassical results are misleading as concerns the plasma edge for they do not adequately take the peculiar local conditions into account, in particular the fact that the density and temperature variation length-scales are quite small. Coupled novel neoclassical equations obtain, not only for the evolution of the density and temperatures, but also for the radial electric field and the evolution of the parallel ion momentum: gyro-stresses and inertia indeed upset the otherwise de facto ambipolarity of particle transport and a radial electric field necessarily builds up. The increased nonlinear character of these revisited neoclassical equations widens the realm of possible plasma behaviors. (author)
Small-angle scattering theory revisited: Photocurrent and spatial localization
DEFF Research Database (Denmark)
Basse, N.P.; Zoletnik, S.; Michelsen, Poul
2005-01-01
In this paper theory on collective scattering measurements of electron density fluctuations in fusion plasmas is revisited. We present the first full derivation of the expression for the photocurrent beginning at the basic scattering concepts. Thereafter we derive detailed expressions for the auto......- and crosspower spectra obtained from measurements. These are discussed and simple simulations made to elucidate the physical meaning of the findings. In this context, the known methods of obtaining spatial localization are discussed and appraised. Where actual numbers are applied, we utilize quantities from two...
NP-hardness of the cluster minimization problem revisited
Adib, Artur B.
2005-10-01
The computational complexity of the 'cluster minimization problem' is revisited (Wille and Vennik 1985 J. Phys. A: Math. Gen. 18 L419). It is argued that the original NP-hardness proof does not apply to pairwise potentials of physical interest, such as those that depend on the geometric distance between the particles. A geometric analogue of the original problem is formulated, and a new proof for such potentials is provided by polynomial time transformation from the independent set problem for unit disk graphs. Limitations of this formulation are pointed out, and new subproblems that bear more direct consequences to the numerical study of clusters are suggested.
NP-hardness of the cluster minimization problem revisited
International Nuclear Information System (INIS)
Adib, Artur B
2005-01-01
The computational complexity of the 'cluster minimization problem' is revisited (Wille and Vennik 1985 J. Phys. A: Math. Gen. 18 L419). It is argued that the original NP-hardness proof does not apply to pairwise potentials of physical interest, such as those that depend on the geometric distance between the particles. A geometric analogue of the original problem is formulated, and a new proof for such potentials is provided by polynomial time transformation from the independent set problem for unit disk graphs. Limitations of this formulation are pointed out, and new subproblems that bear more direct consequences to the numerical study of clusters are suggested
NP-hardness of the cluster minimization problem revisited
Energy Technology Data Exchange (ETDEWEB)
Adib, Artur B [Physics Department, Brown University, Providence, RI 02912 (United States)
2005-10-07
The computational complexity of the 'cluster minimization problem' is revisited (Wille and Vennik 1985 J. Phys. A: Math. Gen. 18 L419). It is argued that the original NP-hardness proof does not apply to pairwise potentials of physical interest, such as those that depend on the geometric distance between the particles. A geometric analogue of the original problem is formulated, and a new proof for such potentials is provided by polynomial time transformation from the independent set problem for unit disk graphs. Limitations of this formulation are pointed out, and new subproblems that bear more direct consequences to the numerical study of clusters are suggested.
REVISITING A CLASSIC: THE PARKER–MOFFATT PROBLEM
Energy Technology Data Exchange (ETDEWEB)
Pezzi, O.; Servidio, S.; Valentini, F.; Malara, F.; Veltri, P. [Dipartimento di Fisica, Università della Calabria, 87036 Rende (CS) (Italy); Parashar, T. N.; Yang, Y.; Matthaeus, W. H. [Department of Physics and Astronomy, University of Delaware, DE 19716 (United States); Vásconez, C. L. [Departamento de Física, Escuela Politécnica Nacional, Quito (Ecuador)
2017-01-10
The interaction of two colliding Alfvén wave packets is described here by means of magnetohydrodynamics (MHD) and hybrid kinetic numerical simulations. The MHD evolution revisits the theoretical insights described by Moffatt, Parker, Kraichnan, Chandrasekhar, and Elsässer in which the oppositely propagating large-amplitude wave packets interact for a finite time, initiating turbulence. However, the extension to include compressive and kinetic effects, while maintaining the gross characteristics of the simpler classic formulation, also reveals intriguing features that go beyond the pure MHD treatment.
Revisiting reflexology: Concept, evidence, current practice, and practitioner training
Embong, Nurul Haswani; Soh, Yee Chang; Ming, Long Chiau; Wong, Tin Wui
2015-01-01
Reflexology is basically a study of how one part of the human body relates to another part of the body. Reflexology practitioners rely on the reflexes map of the feet and hands to all the internal organs and other human body parts. They believe that by applying the appropriate pressure and massage certain spots on the feet and hands, all other body parts could be energized and rejuvenated. This review aimed to revisit the concept of reflexology and examine its effectiveness, practices, and th...
Entropy of measurement and erasure: Szilard's membrane model revisited
Leff, Harvey S.; Rex, Andrew F.
1994-11-01
It is widely believed that measurement is accompanied by irreversible entropy increase. This conventional wisdom is based in part on Szilard's 1929 study of entropy decrease in a thermodynamic system by intelligent intervention (i.e., a Maxwell's demon) and Brillouin's association of entropy with information. Bennett subsequently argued that information acquisition is not necessarily irreversible, but information erasure must be dissipative (Landauer's principle). Inspired by the ensuing debate, we revisit the membrane model introduced by Szilard and find that it can illustrate and clarify (1) reversible measurement, (2) information storage, (3) decoupling of the memory from the system being measured, and (4) entropy increase associated with memory erasure and resetting.
Revisiting Creeping Competences in the EU
DEFF Research Database (Denmark)
Citi, Manuele
2014-01-01
case where secondary legislation was employed to extend a formal treaty-based competence (civilian research and technology policy) to an area that, for historical and strategic reasons, has always been a policy monopoly of national governments: research and technology development policy for security...... and defence. Through the analysis of a large pool of documentary data, I elaborate a set of linked hypotheses about the empirical dynamics of creeping competences, and show how the theory of incomplete contracting is best suited to explain this phenomenon....
Solution NMR structure determination of proteins revisited
International Nuclear Information System (INIS)
Billeter, Martin; Wagner, Gerhard; Wuethrich, Kurt
2008-01-01
This 'Perspective' bears on the present state of protein structure determination by NMR in solution. The focus is on a comparison of the infrastructure available for NMR structure determination when compared to protein crystal structure determination by X-ray diffraction. The main conclusion emerges that the unique potential of NMR to generate high resolution data also on dynamics, interactions and conformational equilibria has contributed to a lack of standard procedures for structure determination which would be readily amenable to improved efficiency by automation. To spark renewed discussion on the topic of NMR structure determination of proteins, procedural steps with high potential for improvement are identified
"Rapid Revisit" Measurements of Sea Surface Winds Using CYGNSS
Park, J.; Johnson, J. T.
2017-12-01
The Cyclone Global Navigation Satellite System (CYGNSS) is a space-borne GNSS-R (GNSS-Reflectometry) mission that launched December 15, 2016 for ocean surface wind speed measurements. CYGNSS includes 8 small satellites in the same LEO orbit, so that the mission provides wind speed products having unprecedented coverage both in time and space to study multi-temporal behaviors of oceanic winds. The nature of CYGNSS coverage results in some locations on Earth experiencing multiple wind speed measurements within a short period of time (a "clump" of observations in time resulting in a "rapid revisit" series of measurements). Such observations could seemingly provide indications of regions experiencing rapid changes in wind speeds, and therefore be of scientific utility. Temporally "clumped" properties of CYGNSS measurements are investigated using early CYGNSS L1/L2 measurements, and the results show that clump durations and spacing vary with latitude. For example, the duration of a clump can extend as long as a few hours at higher latitudes, with gaps between clumps ranging from 6 to as high as 12 hours depending on latitude. Examples are provided to indicate the potential of changes within a clump to produce a "rapid revisit" product for detecting convective activity. Also, we investigate detector design for identifying convective activities. Results from analyses using recent CYGNSS L2 winds will be provided in the presentation.
Revisiting the Decision of Death in Hurst v. Florida.
Cooke, Brian K; Ginory, Almari; Zedalis, Jennifer
2016-12-01
The United States Supreme Court has considered the question of whether a judge or a jury must make the findings necessary to support imposition of the death penalty in several notable cases, including Spaziano v. Florida (1984), Hildwin v. Florida (1989), and Ring v. Arizona (2002). In 2016, the U.S. Supreme Court revisited the subject in Hurst v. Florida Florida Statute § 921.141 allows the judge, after weighing aggravating and mitigating circumstances, to enter a sentence of life imprisonment or death. Before Hurst, Florida's bifurcated sentencing proceedings included an advisory sentence from jurors and a separate judicial hearing without juror involvement. In Hurst, the Court revisited the question of whether Florida's capital sentencing scheme violates the Sixth Amendment, which requires a jury, not a judge, to find each fact necessary to impose a sentence of death in light of Ring In an eight-to-one decision, the Court reversed the judgment of the Florida Supreme Court, holding that the Sixth Amendment requires a jury to find the aggravating factors necessary for imposing the death penalty. The role of Florida juries in capital sentencing proceedings was thereby elevated from advisory to determinative. We examine the Court's decision and offer commentary regarding this shift from judge to jury in the final imposition of the death penalty and the overall effect of this landmark case. © 2016 American Academy of Psychiatry and the Law.
Today's fentanyl crisis: Prohibition's Iron Law, revisited.
Beletsky, Leo; Davis, Corey S
2017-08-01
More than a decade in the making, America's opioid crisis has morphed from being driven by prescription drugs to one fuelled by heroin and, increasingly, fentanyl. Drawing on historical lessons of the era of National Alcohol Prohibition highlights the unintended, but predictable impact of supply-side interventions on the dynamics of illicit drug markets. Under the Iron Law of Prohibition, efforts to interrupt and suppress the illicit drug supply produce economic and logistical pressures favouring ever-more compact substitutes. This iatrogenic progression towards increasingly potent illicit drugs can be curtailed only through evidence-based harm reduction and demand reduction policies that acknowledge the structural determinants of health. Copyright © 2017 Elsevier B.V. All rights reserved.
The Alexander-Zweig (OZI) rule revisited
International Nuclear Information System (INIS)
Lipkin, H.J.
1989-03-01
Predictions, theoretical bases, experimental tests and violations of various versions of the A-Z (OZI) rule are examined. Dynamical mechanisms responsible for violations include allowed two-step transitions via intermediate states containing ordinary hadrons, gluons, flavor-mixed hadrons like η, η' or f 0 (S * ), and exotic hadrons like glueballs, multiquark states and hybrids. All can be produced via a strange component and decay into pions or vice versa. Each case is described by a different mechanism with a different suppression factor. OZI-forbidden production processes for φ and f' mesons are shown on general grounds to be less suppressed than forbidden decays, without assuming the presence of strange quarks in baryons. (author)
Organizational Boundary Change in Industrial Symbiosis: Revisiting the Guitang Group in China
Directory of Open Access Journals (Sweden)
Lin Shi
2017-06-01
Full Text Available This study revisits the Guitang Group, one of the best known industrial symbiosis cases in the sugar industry. Our goal is to offer an evolutionary understanding of industrial symbiosis at the Guitang Group. This article focuses on the organizational boundary change of the Guitang Group over time, and acknowledges this process as one of the seven industrial symbiosis dynamics proposed by Boons et al. We offer a historical view of the critical forces behind Guitang’s industrial symbiosis evolution since the 1950s; particularly how these changes were influenced by broader economic and institutional contexts of importance in China. These insights include the role of institutionalized research and development (R&D as well as technology-oriented leadership as driving forces for Guitang’s innovation, particularly since the 1990s, when greater efficiency and productivity were emphasized, leading to the establishment of further symbiotic relationships in the company’s evolutionary process. As a result, the Guitang Group grew from 2 internal to 11 internal and external symbiotic exchanges and is now a conglomeration with more than 3000 employees generating more than 1 billion RMB (150 million USD in revenue annually. The driving forces of the Guitang Group’s industrial symbiosis evolution helped to create, disseminate and share information by continuously reinforcing the industrial symbiosis message as part of the Guitang Group’s business model and competitive strategy. In addition, state-level policies such as establishing the Guigang (the city where Guitang is located Eco-Industrial Park enabled industrial symbiosis in Guitang. This study provides prospects for future research on the organizational boundary change dynamic of industrial symbiosis in the sugar manufacturing industry and beyond.
BMS3 invariant fluid dynamics at null infinity
Penna, Robert F.
2018-02-01
We revisit the boundary dynamics of asymptotically flat, three dimensional gravity. The boundary is governed by a momentum conservation equation and an energy conservation equation, which we interpret as fluid equations, following the membrane paradigm. We reformulate the boundary’s equations of motion as Hamiltonian flow on the dual of an infinite-dimensional, semi-direct product Lie algebra equipped with a Lie–Poisson bracket. This gives the analogue for boundary fluid dynamics of the Marsden–Ratiu–Weinstein formulation of the compressible Euler equations on a manifold, M, as Hamiltonian flow on the dual of the Lie algebra of \
NEC violation in mimetic cosmology revisited
Directory of Open Access Journals (Sweden)
Anna Ijjas
2016-09-01
Full Text Available In the context of Einstein gravity, if the null energy condition (NEC is satisfied, the energy density in expanding space–times always decreases while in contracting space–times the energy density grows and the universe eventually collapses into a singularity. In particular, no non-singular bounce is possible. It is, though, an open question if this energy condition can be violated in a controlled way, i.e., without introducing pathologies, such as unstable negative-energy states or an imaginary speed of sound. In this letter, we will re-examine the claim that the recently proposed mimetic scenario can violate the NEC without pathologies. We show that mimetic cosmology is prone to gradient instabilities even in cases when the NEC is satisfied (except for trivial examples. Most interestingly, the source of the instability is always the Einstein–Hilbert term in the action. The matter stress-energy component does not contribute spatial gradient terms but instead makes the problematic curvature modes dynamical. We also show that mimetic cosmology can be understood as a singular limit of known, well-behaved theories involving higher-derivative kinetic terms and discuss ways of removing the instability.
Radioecological sensitivity. Danish fallout data revisited
International Nuclear Information System (INIS)
Nielsen, S.P.; Oehlenschlaeger, M.
1999-01-01
Danish fallout data covering four decades are interpreted in terms of radioecological sensitivity. The radioecological sensitivity is the time-integrated radionuclide concentration in an environmental sample from a unit ground deposition (e.g. Bq y kg -1 per Gq m -2 ). The fallout data comprise observed levels of the radionuclides 137 Cs and 90 Sr in precipitation, grass, milk, beef and diet. The data are analysed with different types of radioecological models: traditional UNSCEAR models and more recent dynamic models. The traditional models provide empirical relationships between the annual fallout from precipitation and the annual average levels in grass, milk, beef and diet. The relationships may be derived from spreadsheet calculations. ECOSYS and FARMLAND represent more recent radioecological models, which are available as software for personal computers. These models are more mechanistic and require information on a range of topics, e.g. mode of deposition, nuclide dependent and nuclide independent parameters. The more recent models do not reproduce the fallout data better than the traditional models. But the general features of the more recent models make them suited for prediction of radiological consequences of routine and accidental releases in areas where limited radioecological data are available. The work is part of the NKS/BOK-2.1 project on Important Nordic Food Chains aiming at characterising radioecological sensitivity and variability across the Nordic countries. (au)
Sargent and Lundy containment tests revisited
International Nuclear Information System (INIS)
Henry, Robert E.; Hammersley, Robert J.
2005-01-01
The pressurization experiments performed in the intermediate scale Sargent and Lundy containment test facility provide numerous insights into the dominant heat and mass transfer processes under design basis accident conditions similar to a large break Loss of Coolant Accident (LOCA). These experiments were the first integral tests to examine the containment response to a dynamic blowdown from the Reactor Coolant System (RCS). Measurements included the blowdown rate of the simulated Reactor Pressure Vessel (RPV), the pressure in containment as well as the containment temperatures in the top and bottom of the containment vessel. Furthermore, various experiments were performed with the blowdown location changed from the vessel bottom to the lower third of the vessel, the upper third of the vessel and near the top of the RPV to examine the influence of different types of break elevations, i.e. different characterizations of the exhausting steam-water mixture. Perhaps the most insightful set of measurements from these experiments were those that varied the cold water mass initially resident in the bottom of the simulated containment vessel. The role of this water as a function of its initial mass and the break location showed substantial influence of this water if the blowdown location provided sufficient energy to disperse this cold water into the containment building atmosphere. This is demonstrated in Figure 1 taken from Kolflat, 1960. All of these are relevant to an understanding of the dominant physical processes for this type of postulated accident condition. As such, it is important that all of these insights are retained and used in models for the containment building thermal-hydraulic response under accident conditions. Reference: Kolflat, A., 1960, 'Resulting of 1959 Nuclear Power Plant Containment Test', Sargent and Lundy Report SL-1800; Kolflat, A. and Chittenden, W. A., 1957, 'A New Approach to the Design of Containment Shells for Atomic Power Plants
Markers and mapping revisited: finding your gene.
Jones, Neil; Ougham, Helen; Thomas, Howard; Pasakinskiene, Izolda
2009-01-01
this highly dynamic arena of plant science.
Directory of Open Access Journals (Sweden)
Alyssa K. Whitcraft
2015-01-01
Full Text Available Agriculture is a highly dynamic process in space and time, with many applications requiring data with both a relatively high temporal resolution (at least every 8 days and fine-to-moderate (FTM < 100 m spatial resolution. The relatively infrequent revisit of FTM optical satellite observatories coupled with the impacts of cloud occultation have translated into a barrier for the derivation of agricultural information at the regional-to-global scale. Drawing upon the Group on Earth Observations Global Agricultural Monitoring (GEOGLAM Initiative’s general satellite Earth observation (EO requirements for monitoring of major production areas, Whitcraft et al. (this issue have described where, when, and how frequently satellite data acquisitions are required throughout the agricultural growing season at 0.05°, globally. The majority of areas and times of year require multiple revisits to probabilistically yield a view at least 70%, 80%, 90%, or 95% clear within eight days, something that no present single FTM optical observatory is capable of delivering. As such, there is a great potential to meet these moderate spatial resolution optical data requirements through a multi-space agency/multi-mission constellation approach. This research models the combined revisit capabilities of seven hypothetical constellations made from five satellite sensors—Landsat 7 Enhanced Thematic Mapper (Landsat 7 ETM+, Landsat 8 Operational Land Imager and Thermal Infrared Sensor (Landsat 8 OLI/TIRS, Resourcesat-2 Advanced Wide Field Sensor (Resourcesat-2 AWiFS, Sentinel-2A Multi-Spectral Instrument (MSI, and Sentinel-2B MSI—and compares these capabilities with the revisit frequency requirements for a reasonably cloud-free clear view within eight days throughout the agricultural growing season. Supplementing Landsat 7 and 8 with missions from different space agencies leads to an improved capacity to meet requirements, with Resourcesat-2 providing the largest
The spectroscopic orbit of Capella revisited
Weber, M.; Strassmeier, K. G.
2011-07-01
Context. Capella is among the few binary stars with two evolved giant components. The hotter component is a chromospherically active star within the Hertzsprung gap, while the cooler star is possibly helium-core burning. Aims: The known inclination of the orbital plane from astrometry in combination with precise radial velocities will allow very accurate masses to be determined for the individual Capella stars. This will constrain their evolutionary stage and possibly the role of the active star's magnetic field on the dynamical evolution of the binary system. Methods: We obtained a total of 438 high-resolution échelle spectra during the years 2007-2010 and used the measured velocities to recompute the orbital elements. Our double-lined orbital solution yields average residuals of 64 m s-1 for the cool component and 297 m s-1 for the more rapidly rotating hotter component. Results: The semi-amplitude of the cool component is smaller by 0.045 km s-1 than the orbit determination of Torres et al. from data taken during 1996-1999 but more precise by a factor of 5.5, while for the hotter component it is larger by 0.580 km s-1 and more precise by a factor of 3.6. This corresponds to masses of 2.573 ± 0.009 M⊙ and 2.488 ± 0.008 M⊙ for the cool and hot component, respectively. Their relative errors of 0.34% and 0.30% are about half of the values given in Torres et al. for a combined literature-data solution but with absolute values different by 4% and 2% for the two components, respectively. The mass ratio of the system is therefore q = MA/MB = 0.9673 ± 0.0020. Conclusions: Our orbit is the most precise and also likely to be the most accurate ever obtained for Capella. Based on data obtained with the STELLA robotic telescope in Tenerife, an AIP facility jointly operated by AIP and IAC.Full Table 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A89
Mixture toxicity revisited from a toxicogenomic perspective.
Altenburger, Rolf; Scholz, Stefan; Schmitt-Jansen, Mechthild; Busch, Wibke; Escher, Beate I
2012-03-06
The advent of new genomic techniques has raised expectations that central questions of mixture toxicology such as for mechanisms of low dose interactions can now be answered. This review provides an overview on experimental studies from the past decade that address diagnostic and/or mechanistic questions regarding the combined effects of chemical mixtures using toxicogenomic techniques. From 2002 to 2011, 41 studies were published with a focus on mixture toxicity assessment. Primarily multiplexed quantification of gene transcripts was performed, though metabolomic and proteomic analysis of joint exposures have also been undertaken. It is now standard to explicitly state criteria for selecting concentrations and provide insight into data transformation and statistical treatment with respect to minimizing sources of undue variability. Bioinformatic analysis of toxicogenomic data, by contrast, is still a field with diverse and rapidly evolving tools. The reported combined effect assessments are discussed in the light of established toxicological dose-response and mixture toxicity models. Receptor-based assays seem to be the most advanced toward establishing quantitative relationships between exposure and biological responses. Often transcriptomic responses are discussed based on the presence or absence of signals, where the interpretation may remain ambiguous due to methodological problems. The majority of mixture studies design their studies to compare the recorded mixture outcome against responses for individual components only. This stands in stark contrast to our existing understanding of joint biological activity at the levels of chemical target interactions and apical combined effects. By joining established mixture effect models with toxicokinetic and -dynamic thinking, we suggest a conceptual framework that may help to overcome the current limitation of providing mainly anecdotal evidence on mixture effects. To achieve this we suggest (i) to design studies to
Simulation of Two-Way Pushdown Automata Revisited
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Robert Glück
2013-09-01
Full Text Available The linear-time simulation of 2-way deterministic pushdown automata (2DPDA by the Cook and Jones constructions is revisited. Following the semantics-based approach by Jones, an interpreter is given which, when extended with random-access memory, performs a linear-time simulation of 2DPDA. The recursive interpreter works without the dump list of the original constructions, which makes Cook's insight into linear-time simulation of exponential-time automata more intuitive and the complexity argument clearer. The simulation is then extended to 2-way nondeterministic pushdown automata (2NPDA to provide for a cubic-time recognition of context-free languages. The time required to run the final construction depends on the degree of nondeterminism. The key mechanism that enables the polynomial-time simulations is the sharing of computations by memoization.
Revisiting Johnson and Jackson boundary conditions for granular flows
Energy Technology Data Exchange (ETDEWEB)
Li, Tingwen; Benyahia, Sofiane
2012-07-01
In this article, we revisit Johnson and Jackson boundary conditions for granular flows. The oblique collision between a particle and a flat wall is analyzed by adopting the classic rigid-body theory and a more realistic semianalytical model. Based on the kinetic granular theory, the input parameter for the partial-slip boundary conditions, specularity coefficient, which is not measurable in experiments, is then interpreted as a function of the particle-wall restitution coefficient, the frictional coefficient, and the normalized slip velocity at the wall. An analytical expression for the specularity coefficient is suggested for a flat, frictional surface with a low frictional coefficient. The procedure for determining the specularity coefficient for a more general problem is outlined, and a working approximation is provided.
International Nuclear Information System (INIS)
Hagedorn, Claudia; King, Stephen F.; Luhn, Christoph
2012-01-01
Following the recent results from Daya Bay and RENO, which measure the lepton mixing angle θ 13 l ≈0.15, we revisit a supersymmetric (SUSY) S 4 ×SU(5) model, which predicts tri-bimaximal (TB) mixing in the neutrino sector with θ 13 l being too small in its original version. We show that introducing one additional S 4 singlet flavon into the model gives rise to a sizable θ 13 l via an operator which leads to the breaking of one of the two Z 2 symmetries preserved in the neutrino sector at leading order (LO). The results of the original model for fermion masses, quark mixing and the solar mixing angle are maintained to good precision. The atmospheric and solar mixing angle deviations from TB mixing are subject to simple sum rule bounds.
Response variance in functional maps: neural darwinism revisited.
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Hirokazu Takahashi
Full Text Available The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population.
Response variance in functional maps: neural darwinism revisited.
Takahashi, Hirokazu; Yokota, Ryo; Kanzaki, Ryohei
2013-01-01
The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population.
The random field Blume-Capel model revisited
Santos, P. V.; da Costa, F. A.; de Araújo, J. M.
2018-04-01
We have revisited the mean-field treatment for the Blume-Capel model under the presence of a discrete random magnetic field as introduced by Kaufman and Kanner (1990). The magnetic field (H) versus temperature (T) phase diagrams for given values of the crystal field D were recovered in accordance to Kaufman and Kanner original work. However, our main goal in the present work was to investigate the distinct structures of the crystal field versus temperature phase diagrams as the random magnetic field is varied because similar models have presented reentrant phenomenon due to randomness. Following previous works we have classified the distinct phase diagrams according to five different topologies. The topological structure of the phase diagrams is maintained for both H - T and D - T cases. Although the phase diagrams exhibit a richness of multicritical phenomena we did not found any reentrant effect as have been seen in similar models.
REVISITING THE SCATTERING GREENHOUSE EFFECT OF CO2 ICE CLOUDS
International Nuclear Information System (INIS)
Kitzmann, D.
2016-01-01
Carbon dioxide ice clouds are thought to play an important role for cold terrestrial planets with thick CO 2 dominated atmospheres. Various previous studies showed that a scattering greenhouse effect by carbon dioxide ice clouds could result in a massive warming of the planetary surface. However, all of these studies only employed simplified two-stream radiative transfer schemes to describe the anisotropic scattering. Using accurate radiative transfer models with a general discrete ordinate method, this study revisits this important effect and shows that the positive climatic impact of carbon dioxide clouds was strongly overestimated in the past. The revised scattering greenhouse effect can have important implications for the early Mars, but also for planets like the early Earth or the position of the outer boundary of the habitable zone
Theory of magnetohydrodynamic waves: The WKB approximation revisited
International Nuclear Information System (INIS)
Barnes, A.
1992-01-01
Past treatments of the eikonal or WKB theory of the propagation of magnetohydrodynamics waves have assumed a strictly isentropic background. IF in fact there is a gradient in the background entropy, then in second order in the WKB ordering, adiabatic fluctuations (in the Lagrangian sense) are not strictly isentropic in the Eulerian sense. This means that in the second order of the WKB expansion, which determines the variation of wave amplitude along rays, the violation of isentropy must be accounted for. The present paper revisits the derivation of the WKB approximation for small-amplitude magnetohydrodynamic waves, allowing for possible spatial variation of the background entropy. The equation of variation of wave amplitude is rederived; it is a bilinear equation which, it turns out, can be recast in the action conservation form. It is shown that this action conservation equation is in fact equivalent to the action conservation law obtained from Lagrangian treatments
Revisiting the Performance of MACD and RSI Oscillators
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Terence Tai-Leung Chong
2014-02-01
Full Text Available Chong and Ng (2008 find that the Moving Average Convergence–Divergence (MACD and Relative Strength Index (RSI rules can generate excess return in the London Stock Exchange. This paper revisits the performance of the two trading rules in the stock markets of five other OECD countries. It is found that the MACD(12,26,0 and RSI(21,50 rules consistently generate significant abnormal returns in the Milan Comit General and the S&P/TSX Composite Index. In addition, the RSI(14,30/70 rule is also profitable in the Dow Jones Industrials Index. The results shed some light on investors’ belief in these two technical indicators in different developed markets.
Sparse RNA folding revisited: space-efficient minimum free energy structure prediction.
Will, Sebastian; Jabbari, Hosna
2016-01-01
RNA secondary structure prediction by energy minimization is the central computational tool for the analysis of structural non-coding RNAs and their interactions. Sparsification has been successfully applied to improve the time efficiency of various structure prediction algorithms while guaranteeing the same result; however, for many such folding problems, space efficiency is of even greater concern, particularly for long RNA sequences. So far, space-efficient sparsified RNA folding with fold reconstruction was solved only for simple base-pair-based pseudo-energy models. Here, we revisit the problem of space-efficient free energy minimization. Whereas the space-efficient minimization of the free energy has been sketched before, the reconstruction of the optimum structure has not even been discussed. We show that this reconstruction is not possible in trivial extension of the method for simple energy models. Then, we present the time- and space-efficient sparsified free energy minimization algorithm SparseMFEFold that guarantees MFE structure prediction. In particular, this novel algorithm provides efficient fold reconstruction based on dynamically garbage-collected trace arrows. The complexity of our algorithm depends on two parameters, the number of candidates Z and the number of trace arrows T; both are bounded by [Formula: see text], but are typically much smaller. The time complexity of RNA folding is reduced from [Formula: see text] to [Formula: see text]; the space complexity, from [Formula: see text] to [Formula: see text]. Our empirical results show more than 80 % space savings over RNAfold [Vienna RNA package] on the long RNAs from the RNA STRAND database (≥2500 bases). The presented technique is intentionally generalizable to complex prediction algorithms; due to their high space demands, algorithms like pseudoknot prediction and RNA-RNA-interaction prediction are expected to profit even stronger than "standard" MFE folding. SparseMFEFold is free
Revisiting the stellar velocity ellipsoid-Hubble-type relation: observations versus simulations
Pinna, F.; Falcón-Barroso, J.; Martig, M.; Martínez-Valpuesta, I.; Méndez-Abreu, J.; van de Ven, G.; Leaman, R.; Lyubenova, M.
2018-04-01
The stellar velocity ellipsoid (SVE) in galaxies can provide important information on the processes that participate in the dynamical heating of their disc components (e.g. giant molecular clouds, mergers, spiral density waves, and bars). Earlier findings suggested a strong relation between the shape of the disc SVE and Hubble type, with later-type galaxies displaying more anisotropic ellipsoids and early types being more isotropic. In this paper, we revisit the strength of this relation using an exhaustive compilation of observational results from the literature on this issue. We find no clear correlation between the shape of the disc SVE and morphological type, and show that galaxies with the same Hubble type display a wide range of vertical-to-radial velocity dispersion ratios. The points are distributed around a mean value and scatter of σz/σR = 0.7 ± 0.2. With the aid of numerical simulations, we argue that different mechanisms might influence the shape of the SVE in the same manner and that the same process (e.g. mergers) does not have the same impact in all the galaxies. The complexity of the observational picture is confirmed by these simulations, which suggest that the vertical-to-radial axis ratio of the SVE is not a good indicator of the main source of disc heating. Our analysis of those simulations also indicates that the observed shape of the disc SVE may be affected by several processes simultaneously and that the signatures of some of them (e.g. mergers) fade over time.
Tseng, W. L.; Johnson, R. E.; Tucker, O. J.; Perry, M. E.; Ip, W. H.
2017-12-01
During the Cassini Grand Finale mission, this spacecraft, for the first time, has done the in-situ measurements of Saturn's upper atmosphere and its rings and provides critical information for understanding the coupling dynamics between the main rings and the Saturnian system. The ring atmosphere is the source of neutrals (i.e., O2, H2, H; Tseng et al., 2010; 2013a), which is primarily generated by photolytic decomposition of water ice (Johnson et al., 2006), and plasma (i.e., O2+ and H2+; Tseng et al., 2011) in the Saturnian magnetosphere. In addition, the main rings have strong interaction with Saturn's atmosphere and ionosphere (i.e., a source of oxygen into Saturn's upper atmosphere and/or the "ring rain" in O'Donoghue et al., 2013). Furthermore, the near-ring plasma environment is complicated by the neutrals from both the seasonally dependent ring atmosphere and Enceladus torus (Tseng et al., 2013b), and, possibly, from small grains from the main and tenuous F and G rings (Johnson et al.2017). The data now coming from Cassini Grand Finale mission already shed light on the dominant physics and chemistry in this region of Saturn's magnetosphere, for example, the presence of carbonaceous material from meteorite impacts in the main rings and each gas species have similar distribution in the ring atmosphere. We will revisit the details in our ring atmosphere/ionosphere model to study, such as the source mechanism for the organic material and the neutral-grain-plasma interaction processes.
How Precisely can we Determine the $\\piNN$ Coupling Constant from the Isovector GMO Sum Rule?
Loiseau, B; Thomas, A W
1999-01-01
The isovector GMO sum rule for zero energy forward pion-nucleon scattering iscritically studied to obtain the charged pion-nucleon coupling constant usingthe precise negatively charged pion-proton and pion-deuteron scattering lengthsdeduced recently from pionic atom experiments. This direct determination leadsto a pseudoscalar charged pion-nucleon coupling constant of 14.23 +- 0.09(statistic) +- 0.17 (systematic). We obtain also accurate values for thepion-nucleon scattering lengths.
Electron transfer dynamics: Zusman equation versus exact theory
International Nuclear Information System (INIS)
Shi Qiang; Chen Liping; Nan Guangjun; Xu Ruixue; Yan Yijing
2009-01-01
The Zusman equation has been widely used to study the effect of solvent dynamics on electron transfer reactions. However, application of this equation is limited by the classical treatment of the nuclear degrees of freedom. In this paper, we revisit the Zusman equation in the framework of the exact hierarchical equations of motion formalism, and show that a high temperature approximation of the hierarchical theory is equivalent to the Zusman equation in describing electron transfer dynamics. Thus the exact hierarchical formalism naturally extends the Zusman equation to include quantum nuclear dynamics at low temperatures. This new finding has also inspired us to rescale the original hierarchical equations and incorporate a filtering algorithm to efficiently propagate the hierarchical equations. Numerical exact results are also presented for the electron transfer reaction dynamics and rate constant calculations.
Lee, Seoyoung; Kim, Eun-Kyung
2017-06-01
The purpose of this study was to investigate medical service quality, satisfaction and to examine factors influencing hospital revisit intention of the United Arab Emirates government sponsored patients in Korea. A total of 152 UAE government sponsored patients who visited Korean hospitals participated in the questionnaire survey from August to November 2016. Stepwise multiple regression was used to identify the factors that affected the revisit intention of the participants. The mean scores of medical service quality, satisfaction, and revisit intention were 5.72 out of 7, 88.88 out of 100, 4.59 out of 5, respectively. Medical service quality and satisfaction, Medical service quality and revisit intention, satisfaction and revisit intention were positively correlated. Medical service of physician, visiting routes and responsiveness of medical service quality explained about 23.8% of revisit intention. There are needs for physicians to communicate with patients while ensuring sufficient consultation time based on excellent medical skills and nurses to respond immediately for the patients' needs through an empathic encounter in order to improve medical service quality and patient satisfaction so that to increase the revisit intention of the United Arab Emirates government sponsored patients. Further, it is necessary for the hospitals to have support plans for providing country specialized services in consideration of the UAE culture to ensure that physicians' and nurses' competencies are not undervalued by non-medical service elements such as interpreters and meals. Copyright © 2017. Published by Elsevier B.V.
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Setyo Ferry Wibowo
2016-04-01
Full Text Available The purpose of this research are: 1 To find out the description of destination image, tourist satisfaction, and revisit intention of Betawi cultural village Setu Babakan, 2 test empirically the influence of destination image toward revisit intention of Betawi cultural village Setu Babakan, 3 test empirically the influence of tourist satisfaction toward revisit intention of Betawi cultural village Setu Babakan, 4 test empirically the influence of destination image toward revisit intention of Betawi cultural village Setu Babakan. The object of this research was 200 respondents who have ever visit to Betawi cultural village Setu Babakan at one time. The results of descriptive test explained that the destination image provided is good according to the tourist, so that the tourist is satisfied and want to revisit intention of Betawi cultural village Setu Babakan. The hypothesis test shows: 1 the influence of destination image toward revisit intention by -30%, 2 the influence of tourist satisfaction toward revisit intention by 118%, 3 the influence of destination image toward tourist satisfaction by 92%.
An Adaptive and Hybrid Approach for Revisiting the Visibility Pipeline
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Ícaro Lins Leitão da Cunha
2016-04-01
Full Text Available We revisit the visibility problem, which is traditionally known in Computer Graphics and Vision fields as the process of computing a (potentially visible set of primitives in the computational model of a scene. We propose a hybrid solution that uses a dry structure (in the sense of data reduction, a triangulation of the type J1a, to accelerate the task of searching for visible primitives. We came up with a solution that is useful for real-time, on-line, interactive applications as 3D visualization. In such applications the main goal is to load the minimum amount of primitives from the scene during the rendering stage, as possible. For this purpose, our algorithm executes the culling by using a hybrid paradigm based on viewing-frustum, back-face culling and occlusion models. Results have shown substantial improvement over these traditional approaches if applied separately. This novel approach can be used in devices with no dedicated processors or with low processing power, as cell phones or embedded displays, or to visualize data through the Internet, as in virtual museums applications.
On the ionospheric perturbation for the 1995 Kobe earthquake: revisited
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Masashi Hayakawa
2016-01-01
Full Text Available The presence of seismo-lower ionospheric perturbation for the Kobe earthquake (EQ has been revisited with a relatively new phenomenon of ULF (ultra-low-frequency magnetic field depression effect. By using the ULF data in Japan only at Kakioka belonging to Japan Meteorological Agency (because data from Memambetsu and Kanoya were not available, we have found that a very clear ULF depression was observed at Kakioka on 14 January 1995. A comparison with our former result on subionospheric VLF (very low frequency propagation anomaly indicates that the occurrence of ULF depression exhibits a temporal coincidence (synchronization with that of subionospheric VLF anomaly. This may be acceptable because the ULF depression can be explained in terms of enhanced absorption of magnetospheric ULF waves through the disturbed lower ionosphere prior to an EQ. The result of ULF magnetic field depression in this paper is likely to provide a further support to the presence of the lower ionospheric perturbation before the Kobe EQ.
arXiv Uncertainties in WIMP Dark Matter Scattering Revisited
Ellis, John; Olive, Keith A.
We revisit the uncertainties in the calculation of spin-independent scattering matrix elements for the scattering of WIMP dark matter particles on nuclear matter. In addition to discussing the uncertainties due to limitations in our knowledge of the nucleonic matrix elements of the light quark scalar densities , we also discuss the importances of heavy quark scalar densities , and comment on uncertainties in quark mass ratios. We analyze estimates of the light-quark densities made over the past decade using lattice calculations and/or phenomenological inputs. We find an uncertainty in the combination that is larger than has been assumed in some phenomenological analyses, and a range of that is smaller but compatible with earlier estimates. We also analyze the importance of the {\\cal O}(\\alpha_s^3) calculations of the heavy-quark matrix elements that are now available, which provide an important refinement of the calculation of the spin-independent scattering cross section. We use for illustration a benchmar...
Revisiting scalar geodesic synchrotron radiation in Kerr spacetime
International Nuclear Information System (INIS)
Macedo, Caio F.B.; Crispino, Luis C.B.
2011-01-01
Full text: The Kerr solution [R. P. Kerr, Phys. Rev. D 11, 5 (1963)] is one of the most important black hole solutions of Einstein equations. It describes a chargeless rotating black hole, with Schwarzschild black hole as a particular case. It is estimated, inferred using distinct methods, that most black hole candidates have a considerable value of the rotation parameter [E. Berti, V. Cardoso, and A. Starinets, Classical Quantum Gravity 26, 163001 (2009)]. Although the Schwarzschild solution is suitable for a great variety of phenomena in star and black hole physics, the Kerr solution becomes very important in the explanation of the electrodynamical aspects of accretion disks for binary X-ray sources [The Kerr Spacetime: Rotating Black Holes in General Relativity, edited by D. L. Wiltshire, M. Visser, and S. M. Scott (Cambridge University Press, Cambridge, 2009)]. Thus, the investigation of how radiation emission processes are modified by the nontrivial curvature of rotating black holes is particularly important. As a first approximation to the problem, one can consider a moving particle, minimally coupled to the massless scalar field, in circular geodesic motion. The radiation emitted in this configuration is called scalar geodesic synchrotron radiation. In this work, we revisit the main aspects of scalar geodesic synchrotron radiation in Kerr spacetime, including some effects occurring in the high-frequency approximation. Our results can be readily compared with the results of the equivalent phenomena in Schwarzschild spacetime. (author)
Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction
Sun, Tiancheng; Peng, Yifan; Heidrich, Wolfgang
2017-01-01
Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.
Revisiting NLTE Rovibrational Excitation of CO in UV Irradiated Environments
Zhang, Ziwei; Yang, Benhui H.; Stancil, Phillip C.; Walker, Kyle M.; Forrey, Robert C.; Naduvalath, Balakrishnan
2018-06-01
Being the second most abundant molecule in the ISM, CO has been well observed and studied as a tracer for many astrophysical processes. Highly rovibrationally excited CO emission is used to reveal features in intense UV-irradiated regions such as the inner rim of protoplanetary disks, carbon star envelopes, and star forming regions. Collisional rate coefficients are crucial for non-local thermodynamic equilibrium (NLTE) molecular analysis in such regions, while data for high rovibrational levels for CO were previously unavailable. Here we revisit CO excitation properties with comprehensive collisional data including high rovibrational states (up to v=5 and J=40) colliding with H2, H and He, in various NLTE astrophysical environments with the spectral modeling packages RADEX and Cloudy. We studied line ratio diagnostics between low- and high-vibrational transitions with RADEX. Using Cloudy, we investigated molecular properties in complex environments, such as photodissociation regions and the outflow of the carbon star IRC+10216, illustrating the potential for utilizing high rovibrational NLTE analysis in future astrophysical modeling.This work was supported by NASA Grants NNX15AI61G and NNX16AF09G.
Internal wave focusing revisited; a reanalysis and new theoretical links
International Nuclear Information System (INIS)
Lam, Frans-Peter A; Maas, Leo R M
2008-01-01
An experiment which discussed the appearance of an internal wave attractor in a uniformly stratified, free-surface fluid [Maas, L.R.M., Benielli, D., Sommeria, J., Lam, F.-P.A., 1997. Observation of an internal wave attractor in a confined, stably stratified fluid. Nature 388(6642), 557-561] is revisited. This is done in order to give a more detailed and more accurate description of the underlying focusing process. Evolution of the attractor can now be quantified. For the tank with one sloping sidewall, and for the parameter regime (density stratification, forcing frequency) studied, the inverse exponential growth rate determined at several locations in the fluid turns out to be 122 s always. Only the start and duration of the growth differed: away from the attractor region it appeared later and of shorter duration. Here, these features are interpreted by employing a new theoretical basis that incorporates an external forcing via a surface boundary condition (an infinitesimal barotropic seiche) and that describes the solution in terms of propagating waves.
Updating energy security and environmental policy: Energy security theories revisited.
Proskuryakova, L
2018-06-18
The energy security theories are based on the premises of sufficient and reliable supply of fossil fuels at affordable prices in centralized supply systems. Policy-makers and company chief executives develop energy security strategies based on the energy security theories and definitions that dominate in the research and policy discourse. It is therefore of utmost importance that scientists revisit these theories in line with the latest changes in the energy industry: the rapid advancement of renewables and smart grid, decentralization of energy systems, new environmental and climate challenges. The study examines the classic energy security concepts (neorealism, neoliberalism, constructivism and international political economy) and assesses if energy technology changes are taken into consideration. This is done through integrative literature review, comparative analysis, identification of 'international relations' and 'energy' research discourse with the use of big data, and case studies of Germany, China, and Russia. The paper offers suggestions for revision of energy security concepts through integration of future technology considerations. Copyright © 2018 Elsevier Ltd. All rights reserved.
ISLAM, ADAT, AND THE STATE: Matrifocality in Aceh Revisited
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Eka Srimulyani
2010-08-01
Full Text Available Matrifocality has been a rooted tradition in the social history of the community in Aceh. The principles of matrifocality have also affected on how women are positioned in the community, and the socio-gender relation within the community. The fact that Aceh has strongly associated to the Islamic values that claimed to support the paternal traditions. Apparently, the Islamic values and the local matrifocality practices juxtaposed through the roles of adat, which considered as inseparable to Islamic law or teaching, or in local term known as zat ngeun sifeut. Another point in revisiting matrifocality in Aceh in Aceh is an examination of how gender state ideology, particularly during the New Order Regime disregarded some local gender practices across some ethnics in the archipelago. Meanwhile, the state also hegemonied and promoted particular gender state ideology such as state ibuism. Nonetheless, the modernity and social changes have also contributed to the shifting of some matrifocality practices in contemporary Acehnese society. However, since the matrifocality has a strong root in the social life of the community, the principles of the matrifocality still survived until currently, although it transformed into ‘new matrifocality’ practices. Keywords: matrifocality, Aceh, gender, shari‘a law
Biogas from Macroalgae: is it time to revisit the idea?
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Hughes Adam D
2012-11-01
Full Text Available Abstract The economic and environmental viability of dedicated terrestrial energy crops is in doubt. The production of large scale biomass (macroalgae for biofuels in the marine environment was first tested in the late 1960’s. The culture attempts failed due to the engineering challenges of farming offshore. However the energy conversion via anaerobic digestion was successful as the biochemical composition of macroalgae makes it an ideal feedstock. The technology for the mass production of macroalgae has developed principally in China and Asia over the last 50 years to such a degree that it is now the single largest product of aquaculture. There has also been significant technology transfer and macroalgal cultivation is now well tried and tested in Europe and America. The inherent advantage of production of biofuel feedstock in the marine environment is that it does not compete with food production for land or fresh water. Here we revisit the idea of the large scale cultivation of macroalgae at sea for subsequent anaerobic digestion to produce biogas as a source of renewable energy, using a European case study as an example.
Cation dyshomeostasis and cardiomyocyte necrosis: the Fleckenstein hypothesis revisited
Borkowski, Brian J.; Cheema, Yaser; Shahbaz, Atta U.; Bhattacharya, Syamal K.; Weber, Karl T.
2011-01-01
An ongoing loss of cardiomyocytes to apoptotic and necrotic cell death pathways contributes to the progressive nature of heart failure. The pathophysiological origins of necrotic cell loss relate to the neurohormonal activation that accompanies acute and chronic stressor states and which includes effector hormones of the adrenergic nervous system. Fifty years ago, Albrecht Fleckenstein and coworkers hypothesized the hyperadrenergic state, which accompanies such stressors, causes cardiomyocyte necrosis based on catecholamine-initiated excessive intracellular Ca2+ accumulation (EICA), and mitochondrial Ca2+ overloading in particular, in which the ensuing dysfunction and structural degeneration of these organelles leads to necrosis. In recent years, two downstream factors have been identified which, together with EICA, constitute a signal–transducer–effector pathway: (i) mitochondria-based induction of oxidative stress, in which the rate of reactive oxygen metabolite generation exceeds their rate of detoxification by endogenous antioxidant defences; and (ii) the opening of the mitochondrial inner membrane permeability transition pore (mPTP) followed by organellar swelling and degeneration. The pathogenesis of stress-related cardiomyopathy syndromes is likely related to this pathway. Other factors which can account for cytotoxicity in stressor states include: hypokalaemia; ionized hypocalcaemia and hypomagnesaemia with resultant elevations in parathyroid hormone serving as a potent mediator of EICA; and hypozincaemia with hyposelenaemia, which compromise antioxidant defences. Herein, we revisit the Fleckenstein hypothesis of EICA in leading to cardiomyocyte necrosis and the central role played by mitochondria. PMID:21398641
The evolution of the mitochondrial genetic code in arthropods revisited.
Abascal, Federico; Posada, David; Zardoya, Rafael
2012-04-01
A variant of the invertebrate mitochondrial genetic code was previously identified in arthropods (Abascal et al. 2006a, PLoS Biol 4:e127) in which, instead of translating the AGG codon as serine, as in other invertebrates, some arthropods translate AGG as lysine. Here, we revisit the evolution of the genetic code in arthropods taking into account that (1) the number of arthropod mitochondrial genomes sequenced has triplicated since the original findings were published; (2) the phylogeny of arthropods has been recently resolved with confidence for many groups; and (3) sophisticated probabilistic methods can be applied to analyze the evolution of the genetic code in arthropod mitochondria. According to our analyses, evolutionary shifts in the genetic code have been more common than previously inferred, with many taxonomic groups displaying two alternative codes. Ancestral character-state reconstruction using probabilistic methods confirmed that the arthropod ancestor most likely translated AGG as lysine. Point mutations at tRNA-Lys and tRNA-Ser correlated with the meaning of the AGG codon. In addition, we identified three variables (GC content, number of AGG codons, and taxonomic information) that best explain the use of each of the two alternative genetic codes.
Evans Blue Dye: A Revisit of Its Applications in Biomedicine.
Yao, Linpeng; Xue, Xing; Yu, Peipei; Ni, Yicheng; Chen, Feng
2018-01-01
Evans blue (EB) dye has owned a long history as a biological dye and diagnostic agent since its first staining application by Herbert McLean Evans in 1914. Due to its high water solubility and slow excretion, as well as its tight binding to serum albumin, EB has been widely used in biomedicine, including its use in estimating blood volume and vascular permeability, detecting lymph nodes, and localizing the tumor lesions. Recently, a series of EB derivatives have been labeled with PET isotopes and can be used as theranostics with a broad potential due to their improved half-life in the blood and reduced release. Some of EB derivatives have even been used in translational applications in clinics. In addition, a novel necrosis-avid feature of EB has recently been reported in some preclinical animal studies. Given all these interesting and important advances in EB study, a comprehensive revisiting of EB has been made in its biomedical applications in the review.
Revisiting reflexology: Concept, evidence, current practice, and practitioner training.
Embong, Nurul Haswani; Soh, Yee Chang; Ming, Long Chiau; Wong, Tin Wui
2015-10-01
Reflexology is basically a study of how one part of the human body relates to another part of the body. Reflexology practitioners rely on the reflexes map of the feet and hands to all the internal organs and other human body parts. They believe that by applying the appropriate pressure and massage certain spots on the feet and hands, all other body parts could be energized and rejuvenated. This review aimed to revisit the concept of reflexology and examine its effectiveness, practices, and the training for reflexology practitioners. PubMed, SCOPUS, Google Scholar, and SpringerLink databases were utilized to search the following medical subject headings or keywords: foot massage, reflexology, foot reflexotherapy, reflexological treatment, and zone therapy. The articles published for the last 10 years were included. Previous systematic reviews failed to show concrete evidence for any specific effect of reflexology in any conditions. Due to its non-invasive, non-pharmacological complementary nature, reflexology is widely accepted and anecdotal evidence of positive effect reflexology in a variety of health conditions are available. Adequate training for practitioners is necessary to ensure the consistency of service provided.
Revisiting reflexology: Concept, evidence, current practice, and practitioner training
Directory of Open Access Journals (Sweden)
Nurul Haswani Embong
2015-10-01
Full Text Available Reflexology is basically a study of how one part of the human body relates to another part of the body. Reflexology practitioners rely on the reflexes map of the feet and hands to all the internal organs and other human body parts. They believe that by applying the appropriate pressure and massage certain spots on the feet and hands, all other body parts could be energized and rejuvenated. This review aimed to revisit the concept of reflexology and examine its effectiveness, practices, and the training for reflexology practitioners. PubMed, SCOPUS, Google Scholar, and SpringerLink databases were utilized to search the following medical subject headings or keywords: foot massage, reflexology, foot reflexotherapy, reflexological treatment, and zone therapy. The articles published for the last 10 years were included. Previous systematic reviews failed to show concrete evidence for any specific effect of reflexology in any conditions. Due to its non-invasive, non-pharmacological complementary nature, reflexology is widely accepted and anecdotal evidence of positive effect reflexology in a variety of health conditions are available. Adequate training for practitioners is necessary to ensure the consistency of service provided.
Finite density two color chiral perturbation theory revisited
Adhikari, Prabal; Beleznay, Soma B.; Mannarelli, Massimo
2018-06-01
We revisit two-color, two-flavor chiral perturbation theory at finite isospin and baryon density. We investigate the phase diagram obtained varying the isospin and the baryon chemical potentials, focusing on the phase transition occurring when the two chemical potentials are equal and exceed the pion mass (which is degenerate with the diquark mass). In this case, there is a change in the order parameter of the theory that does not lend itself to the standard picture of first order transitions. We explore this phase transition both within a Ginzburg-Landau framework valid in a limited parameter space and then by inspecting the full chiral Lagrangian in all the accessible parameter space. Across the phase transition between the two broken phases the order parameter becomes an SU(2) doublet, with the ground state fixing the expectation value of the sum of the magnitude squared of the pion and the diquark fields. Furthermore, we find that the Lagrangian at equal chemical potentials is invariant under global SU(2) transformations and construct the effective Lagrangian of the three Goldstone degrees of freedom by integrating out the radial fluctuations.
Revisitation: a trans phenomenology of the media image
Directory of Open Access Journals (Sweden)
Cael M Keegan
2016-12-01
Full Text Available How might certain moving images move us into transgender becoming? The recent proliferation of transgender images in the media of the Global North has been widely regarded as supporting transgender political and social equality. But do these images do justice to the complexity of transgender lives? Who are images of transgender identity made for, and whose interests do they serve? Instead of discussing media that produce a transgender object for public consumption, this essay’s author is interested in theorizing a trans point of media reception for the popular image. This essay illustrates how transgender subjects might fashion their own archives of becoming through encounters with media that unintentionally support transgender embodiment as a possibility in the world. Revisiting his phenomenological encounters with the film Under the Skin and the “Milk: It Does a Body Good” ad campaign, the author analyzes how certain media objects have the unexpected power to “move” the transgender subject into becoming.
Revisited global drift fluid model for linear devices
International Nuclear Information System (INIS)
Reiser, Dirk
2012-01-01
The problem of energy conserving global drift fluid simulations is revisited. It is found that for the case of cylindrical plasmas in a homogenous magnetic field, a straightforward reformulation is possible avoiding simplifications leading to energetic inconsistencies. The particular new feature is the rigorous treatment of the polarisation drift by a generalization of the vorticity equation. The resulting set of model equations contains previous formulations as limiting cases and is suitable for efficient numerical techniques. Examples of applications on studies of plasma blobs and its impact on plasma target interaction are presented. The numerical studies focus on the appearance of plasma blobs and intermittent transport and its consequences on the release of sputtered target materials in the plasma. Intermittent expulsion of particles in radial direction can be observed and it is found that although the neutrals released from the target show strong fluctuations in their propagation into the plasma column, the overall effect on time averaged profiles is negligible for the conditions considered. In addition, the numerical simulations are utilised to perform an a-posteriori assessment of the magnitude of energetic inconsistencies in previously used simplified models. It is found that certain popular approximations, in particular by the use of simplified vorticity equations, do not significantly affect energetics. However, popular model simplifications with respect to parallel advection are found to provide significant deterioration of the model consistency.
ARCHETYPES AND MYTHOLOGICAL MOTIFS: JOHN UPDIKE’S LEGACY REVISITED
Directory of Open Access Journals (Sweden)
Loreta Ulvydienė
2018-04-01
Full Text Available John Updike is widely considered to be one of the greatest, one of the most popular and sometimes most controversial writers concerned with the American small town and middle-class materialism. A lot of literary critics and researchers observe that Updike’s finest work came from his exploration of ordinary America and from his use of elegant prose, rich with metaphor, to portray the public and private feelings of Americans, their daily rounds of life. In addition, discussing Updike’s individual works a lot of literary critics and researchers have observed the writer’s attempts to re-write myth in “the mythical age”1 of the twentieth century. Naturally enough, as the return to myth is assumed to be a certain feature of the Modernist movement, half a century later since Updike’s famous novel Centaur was penned, it is indispensable to re-examine the writer’s fictional intentions in the usage of myth. More importantly, it is needful to determine whether we can see the mythic elements and realistic details as a continuum or as the contrasted opposites in his so called “historical chronicles”. Updike’s novels and stories are filled with mythological motifs and character archetypes. Thus, the study aims at revisiting John Updike’s creation considering mythological elements and archetypal images of his heroes alongside with heroic masculinity, war, terrorism and American perfectionism.
Revisiting the quantum Szilard engine with fully quantum considerations
Energy Technology Data Exchange (ETDEWEB)
Li, Hai [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); School of Information and Electronics Engineering, Shandong Institute of Business and Technology, Yantai 264000 (China); Zou, Jian, E-mail: zoujian@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Li, Jun-Gang; Shao, Bin [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Wu, Lian-Ao [Department of Theoretical Physics and History of Science, The Basque Country University (EHU/UPV), P.O. Box 644, ES-48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, ES-48011 Bilbao (Spain)
2012-12-15
By considering level shifting during the insertion process we revisit the quantum Szilard engine (QSZE) with fully quantum consideration. We derive the general expressions of the heat absorbed from thermal bath and the total work done to the environment by the system in a cycle with two different cyclic strategies. We find that only the quantum information contributes to the absorbed heat, and the classical information acts like a feedback controller and has no direct effect on the absorbed heat. This is the first demonstration of the different effects of quantum information and classical information for extracting heat from the bath in the QSZE. Moreover, when the well width L{yields}{infinity} or the temperature of the bath T{yields}{infinity} the QSZE reduces to the classical Szilard engine (CSZE), and the total work satisfies the relation W{sub tot}=k{sub B}Tln2 as obtained by Sang Wook Kim et al. [S.W. Kim, T. Sagawa, S. De Liberato, M. Ueda, Phys. Rev. Lett. 106 (2011) 070401] for one particle case. - Highlights: Black-Right-Pointing-Pointer For the first time analyze the QSZE by considering energy level shifts. Black-Right-Pointing-Pointer Find different roles played by classical and quantum information in the QSZE. Black-Right-Pointing-Pointer The amount of work extracted depends on the cyclic strategies of the QSZE. Black-Right-Pointing-Pointer Verify that the QSZE will reduce to the CSZE in the classical limits.
Revisiting Cross-Channel Information Transfer for Chromatic Aberration Correction
Sun, Tiancheng
2017-12-25
Image aberrations can cause severe degradation in image quality for consumer-level cameras, especially under the current tendency to reduce the complexity of lens designs in order to shrink the overall size of modules. In simplified optical designs, chromatic aberration can be one of the most significant causes for degraded image quality, and it can be quite difficult to remove in post-processing, since it results in strong blurs in at least some of the color channels. In this work, we revisit the pixel-wise similarity between different color channels of the image and accordingly propose a novel algorithm for correcting chromatic aberration based on this cross-channel correlation. In contrast to recent weak prior-based models, ours uses strong pixel-wise fitting and transfer, which lead to significant quality improvements for large chromatic aberrations. Experimental results on both synthetic and real world images captured by different optical systems demonstrate that the chromatic aberration can be significantly reduced using our approach.
The hateful patient revisited: Relevance for 21st century medicine.
Strous, Rael D; Ulman, Anne-Marie; Kotler, Moshe
2006-10-01
While the practice of medicine has changed over the years, including technological advances, access to medical information, and the narrowing of socio-economic and educational gaps between the clinician and his/her patients, the importance of the doctor-patient relationship has not diminished over time. This can be a very rewarding interaction. However, many physicians experience a great deal of anger, inadequacy and frustration, and much of the actual practice of medicine may become a burden rather than a source of satisfaction. Physicians may encounter a subset of patients who engender strong negative feelings, despair and even downright malice. An understanding of the "hateful patient" can therefore be very informative to the physician. Several categories of such patients may be described, and sensitivity to the phenomenon will lead to improved physician well-being, less self-destructive patient behavior and a lower risk of litigation. Several factors may assist the 21st century physician in managing the "hateful patient" in an empathic manner and in making some sense of why the patient has resorted to negative response patterns. Ultimately, a failure to consider these issues will result in poorer medical care and, no less important, reduced satisfaction of both patients and doctors. The intention of this article is to revisit the concept and to place it in the context of contemporary medical practice.
International Nuclear Information System (INIS)
Zhang Baocheng; Cai Qingyu; Zhan Mingsheng; You Li
2011-01-01
Research Highlights: → Information is found to be encoded and carried away by Hawking radiations. → Entropy is conserved in Hawking radiation. → We thus conclude no information is lost. → The dynamics of black hole may be unitary. - Abstract: We revisit in detail the paradox of black hole information loss due to Hawking radiation as tunneling. We compute the amount of information encoded in correlations among Hawking radiations for a variety of black holes, including the Schwarzchild black hole, the Reissner-Nordstroem black hole, the Kerr black hole, and the Kerr-Newman black hole. The special case of tunneling through a quantum horizon is also considered. Within a phenomenological treatment based on the accepted emission probability spectrum from a black hole, we find that information is leaked out hidden in the correlations of Hawking radiation. The recovery of this previously unaccounted for information helps to conserve the total entropy of a system composed of a black hole plus its radiations. We thus conclude, irrespective of the microscopic picture for black hole collapsing, the associated radiation process: Hawking radiation as tunneling, is consistent with unitarity as required by quantum mechanics.
International Nuclear Information System (INIS)
Noh, Jae Soo; Park, Younwon; Song, Sub Lee; Kim, Hyeun Min
2016-01-01
The integrity of storage facility and also of the spent nuclear fuel itself is considered very important. Storage casks can be located in a designated area on a site or in a designated storage building. A number of different designs for dry storage have been developed and used in different countries. Dry storage system was classified into two categories by IAEA. One is container including cask and silo, the other one is vault. However, there is various way of categorization for dry storage system. Dry silo and cask are usually classified separately, so the dry storage system can be classified into three different types. Furthermore, dry cask storage can be categorized into two types based on the type of the materials, concrete cask and metal cask. In this paper, the design characteristics of dry storage cask are introduced and computational fluid dynamics (CFD) based thermal analysis for concrete cask is revisited. Basic principles for dry storage cask design were described. Based on that, thermal analysis of concrete dry cask was introduced from the study of H. M. Kim et al. From the CFD calculation, the temperature of concrete wall was maintained under the safety criteria. From this fundamental analysis, further investigations are expected. For example, thermal analysis on the metal cask, thermal analysis on horizontally laid spent nuclear fuel assemblies for transportation concerns, and investigations on better performance of natural air circulation in dry cask can be promising candidates
Energy Technology Data Exchange (ETDEWEB)
Noh, Jae Soo [ACT Co. Ltd., Daejeon (Korea, Republic of); Park, Younwon; Song, Sub Lee [BEES Inc., Daejeon (Korea, Republic of); Kim, Hyeun Min [KAIST, Daejeon (Korea, Republic of)
2016-10-15
The integrity of storage facility and also of the spent nuclear fuel itself is considered very important. Storage casks can be located in a designated area on a site or in a designated storage building. A number of different designs for dry storage have been developed and used in different countries. Dry storage system was classified into two categories by IAEA. One is container including cask and silo, the other one is vault. However, there is various way of categorization for dry storage system. Dry silo and cask are usually classified separately, so the dry storage system can be classified into three different types. Furthermore, dry cask storage can be categorized into two types based on the type of the materials, concrete cask and metal cask. In this paper, the design characteristics of dry storage cask are introduced and computational fluid dynamics (CFD) based thermal analysis for concrete cask is revisited. Basic principles for dry storage cask design were described. Based on that, thermal analysis of concrete dry cask was introduced from the study of H. M. Kim et al. From the CFD calculation, the temperature of concrete wall was maintained under the safety criteria. From this fundamental analysis, further investigations are expected. For example, thermal analysis on the metal cask, thermal analysis on horizontally laid spent nuclear fuel assemblies for transportation concerns, and investigations on better performance of natural air circulation in dry cask can be promising candidates.
New meson-nucleus dynamics from studies of (π,eta) and (π,2π) reactions
International Nuclear Information System (INIS)
Liu, L.C.
1985-01-01
The production of eta particles by pion collisions with nucleons, the reaction with the lowest genuine two-body reaction threshold, is discussed. For simple kinematic reasons, the threshold for nuclear pionic eta production reactions is much lower than 661 MeV. Using an off-shell model for the eta production amplitudes, theoretical cross sections are given for the reaction 3 He(π - ,eta) 3 H(g.s.) at 620 and 720 MeV/c. Pion-induced single pion production is then treated. Because the basic cross sections for this reaction becomes comparable to the pion-nucleon elastic scattering cross section at pion kinetic energies of about 600 MeV and exceeds the elastic scattering cross section at 1 GeV, it is believed that the (π,2π) reaction in complex nuclei represents a powerful tool to study nuclei at pion energies above the resonance region. Theoretical cross section ratios are given for 40 Ca at three different pion energies accessible at LAMPF. Also, the corresponding cross-section ratios are presented on a free proton. 14 refs., 7 figs
K Mbugua The Problem of Hell Revisited pp93-103
African Journals Online (AJOL)
K Mbugua
The Problem of Hell Revisited: Towards a Gentler Theology of Hell 93 ... One who, after He has killed, has authority to cast into hell; yes, I tell you, fear. Him! .... Suppose your spouse or parent or child goes to hell and you go to heaven.
Shim, Jenna Min
2011-01-01
At the current historical juncture in which differences and inequalities are surfacing greater than ever in the world, societies, and schools, the main goal of this essay is to revisit the aspects of structuralism that can potentially contribute productively to understanding the invisible structures and forces that everyone carries (mostly…
Revisiting the Metaphor of the Island: Challenging "World Culture" from an Island Misunderstood
Rappleye, Jeremy
2015-01-01
This article revisits the newly "discovered" island that world culture theorists have repeatedly utilised to explain their theoretical stance, conceptual preferences and methodological approach. Yet, it seeks to (re)connect world culture with the real world by replacing their imagined atoll with a real one--the island-nation of Japan. In…
Asian Lifelong Learning in the Context of a Global Knowledge Economy: A Task Re-Visited
Han, Soonghee
2007-01-01
This article revisits and reinterprets my previous paper. It is a snapshot of the lifelong learning system building in selected Asian countries, reflected in the mirror of the Asian Financial Crisis in the 1997s and the aftermath of that event. I reconsidered the arguments (1) the economic recession had delivered a global dimension of lifelong…
The Peter Effect Revisited: Reading Habits and Attitudes of College Students
Applegate, Anthony J.; Applegate, Mary DeKonty; Mercantini, Martha A.; McGeehan, Catherine M.; Cobb, Jeanne B.; DeBoy, Joanne R.; Modla, Virginia B.; Lewinski, Kimberly E.
2014-01-01
Certainly a primary goal of literacy education is the creation of avid, enthusiastic, and highly motivated readers. However, in this article revisiting the Peter Effect (Applegate & Applegate, 2004), researchers surveyed more than 1,000 college sophomores and found strikingly low levels of enthusiasm for reading. Only 46.6% of surveyed…
Park, Namgyoo K.; Chun, Monica Youngshin; Lee, Jinju
2016-01-01
Compared to the significant development of creativity studies, individual creativity research has not reached a meaningful consensus regarding the most valid and reliable method for assessing individual creativity. This study revisited 2 of the most popular methods for assessing individual creativity: subjective and objective methods. This study…
van Kesteren, J.N.
2014-01-01
The link between gun ownership victimisation by violent crime remains one of the most contested issues in criminology. Some authors claim that high gun availability facilitates serious violence. Others claim that gun ownership prevents crime. This article revisits these issues using individual and
Rodolfo M. Nayga, Jr.; Wipon Aiew; Richard Woodward
2005-01-01
Many empirical studies have discovered large discrepancies between willingness to pay (WTP) and willingness to accept (WTA) measures. This paper revisits the WTP and WTA divergence issue using a non-hypothetical market experiment, actual products, cash, and exchange in a market setting. We find WTA/WTP ratios that are significantly lower than most such studies.
Maresh-Fuehrer, Michelle M.
2015-01-01
The purpose of this study was to revisit Coombs' suggestions for teaching the crisis communication course using service-learning as a framework. The author sought to assess the effectiveness of using this method in terms of the benefits to both students and the partnering organization and students' perceptions of whether they met the learning…
Matthes, J.; Wonneberger, A.
2014-01-01
This article revisits the widely believed notion of the skeptical green consumer, in other words, that green consumers tend to distrust green advertising. Study 1, a survey of U.S. consumers, found no positive relationship between green consumerism and general ad skepticism. However, green
Masood, W.; Mirza, Arshad M.; Nargis, Shahida
2010-08-01
The coupled Shukla-Varma (SV) and convective cell mode is revisited in classical and quantum dusty magnetoplasmas. It is shown that the inclusion of electron thermal effects modifies the original coupled SV and convective cell mode. It is also discussed how the quantum effects can be incorporated in the coupled SV and convective cell mode.
The Best and the Rest: Revisiting the Norm of Normality of Individual Performance
O'Boyle, Ernest, Jr.; Aguinis, Herman
2012-01-01
We revisit a long-held assumption in human resource management, organizational behavior, and industrial and organizational psychology that individual performance follows a Gaussian (normal) distribution. We conducted 5 studies involving 198 samples including 633,263 researchers, entertainers, politicians, and amateur and professional athletes.…
Characteristics of revisits of children at risk for serious infections in pediatric emergency care
E. De Vos-Kerkhof (Evelien); D.H.F. Geurts (Dorien); E.W. Steyerberg (Ewout); M. Lakhanpaul (Monica); H.A. Moll (Henriëtte); R. Oostenbrink (Rianne)
2018-01-01
textabstractIn this study, we aimed to identify characteristics of (unscheduled) revisits and its optimal time frame after Emergency Department (ED) discharge. Children with fever, dyspnea, or vomiting/diarrhea (1 month–16 years) who attended the ED of Erasmus MC-Sophia, Rotterdam (2010–2013), the
Teacher Communication Concerns Revisited: Calling into Question the Gnawing Pull towards Equilibrium
Dannels, Deanna P.
2015-01-01
This study revisits the long-standing teacher communication concerns framework originating over three decades ago. Analysis of 10 years of contemporary GTA teacher communication concerns reveals a typology of 10 concerns, which taken together construct teaching as a process of negotiating relationships, managing identities, and focusing attention.…
Re-Visit to the School Nurse and Adolescents' Medicine Use
Borup, Ina K.; Andersen, Anette; Holstein, Bjorn E.
2011-01-01
Objective: To examine if students who re-visit the school nurse use medicines differently than other students when exposed to aches and psychological problems. Methods: The study includes all 11-, 13- and 15-year-old students from a random sample of schools in Denmark, response rate 87 per cent, n = 5,205. The data collection followed the…
My First CMC Article Revisited: A Window on Spanish L2 Interlanguage
Blake, Robert
2016-01-01
The computer-assisted language learning (CALL) field seems to change overnight with new technological affordances. Blake revisits his 2000 "LLT" article on computer-mediation communication (CMC) in order to reflect on how the field has examined this topic over the past decade or so. While the Interaction Hypothesis continues to guide…
Revisiting Learning in Higher Education--Framing Notions Redefined through an Ecological Perspective
Damsa, Crina; Jornet, Alfredo
2016-01-01
This article employs an ecological perspective as a means of revisiting the notion of learning, with a particular focus on learning in higher education. Learning is reconceptualised as a process entailing mutually constitutive, epistemic, social and affective relations in which knowledge, identity and agency become collective achievements of whole…
Commentary on "Distributed Revisiting: An Analytic for Retention of Coherent Science Learning"
Hewitt, Jim
2015-01-01
The article, "Distributed Revisiting: An Analytic for Retention of Coherent Science Learning" is an interesting study that operates at the intersection of learning theory and learning analytics. The authors observe that the relationship between learning theory and research in the learning analytics field is constrained by several…
Double digest revisited : Complexity and Approximability in the Presence of Noisy Data
Cieliebak, Mark; Eidenbenz, Stephan; Woeginger, Gerhard; Warnow, Tandy; Zhu, Binhai
2003-01-01
We revisit the Double Digest problem, which occurs in sequencing of large DNA strings and consists of reconstructing the relative positions of cut sites from two different enzymes: we first show that Double Digest is strongly NP-complete, improving upon previous results that only showed weak
Creative Experience and Revisit Intention of Handmade Oriental Parasol Umbrella in Kaohsiung
Yi-Ju Lee
2015-01-01
This study identified the hypothesised relationship between creative experience, and revisit intention of handmade oriental parasol umbrella in Kaohsiung, Taiwan. A face-to-face questionnaire survey was administered in Meinong town, Kaohsiung. The components of creative experience were found as "sense of achievement", "unique learning" and "interaction with instructors" in creative tourism. The result also revealed significant positive relationships between creative exper...
Rudy M. Schuster; Laura Sullivan; Duarte Morais; Diane Kuehn
2009-01-01
This analysis explores the differences in Affective and Cognitive Destination Image among three Hudson River Valley (New York) tourism communities. Multiple regressions were used with six dimensions of visitors' images to predict future intention to revisit. Two of the three regression models were significant. The only significantly contributing independent...
Pedestrian crowd dynamics in merging sections: Revisiting the ;faster-is-slower; phenomenon
Shahhoseini, Zahra; Sarvi, Majid; Saberi, Meead
2018-02-01
The study of the discharge of active or self-driven matter in narrow passages has become of the growing interest in a variety of fields. The question has particularly important practical applications for the safety of pedestrian human flows notably in emergency scenarios. It has been suggested predominantly through simulation in some theoretical studies as well as through few experimentations that under certain circumstances, an elevated vigour to escape may exacerbate the outflow and cause further delay although the experimental evidence is rather mixed. The dimensions of this complex phenomenon known as the "faster-is slower" effect are of crucial importance to be understood owing to its potential practical implications for the emergency management. The contextual requirements of observing this phenomenon are yet to be identified. It is not clear whether a "do not speed up" policy is universally beneficial and advisable in an evacuation scenario. Here for the first time we experimentally examine this phenomenon in relation to the pedestrian flows at merging sections as a common geometric feature of crowd egress. Various merging angles and three different speed regimes were examined in high-density laboratory experiments. The measurements of flow interruptions and egress efficiency all indicated that the pedestrians were discharged faster when moving at elevated speed levels. We also observed clear dependencies between the discharge rate and the physical layout of the merging with certain designs clearly outperforming others. But regardless of the design, we observed faster throughput and greater avalanche sizes when we instructed pedestrians to run. Our results give the suggestion that observation of the faster-is-slower effect may necessitate certain critical conditions including passages being overly narrow relative to the size of participles (pedestrians) to create long-lasting blockages. The faster-is-slower assumption may not be universal and there may be circumstances where faster is, in fact, faster for evacuees. In the light of these findings, we suggest that it is important to identify and formulate those conditions so they can be disentangled from one another in the models. Misguided overgeneralisations may have unintended adverse ramifications for the safe evacuation management, and this highlights the need for further exploration of this phenomenon.
Electrical lysis: dynamics revisited and advances in On-chip operation.
Morshed, Bashir; Shams, Maitham; Mussivand, Tofy
2013-01-01
Electrical lysis (EL) is the process of breaking the cell membrane to expose the internal contents under an applied high electric field. Lysis is an important phenomenon for cellular analysis, medical treatment, and biofouling control. This paper aims to review, summarize, and analyze recent advancements on EL. Major databases including PubMed, Ei Engineering Village, IEEE Xplore, and Scholars Portal were searched using relevant keywords. More than 50 articles published in English since 1997 are cited in this article. EL has several key advantages compared to other lysis techniques such as chemical, mechanical, sonication, or laser, including rapid speed of operation, ability to control, miniaturization, low cost, and low power requirement. A variety of cell types have been investigated for including protoplasts, E. coli, yeasts, blood cells, and cancer cells. EL has been developed and applied for decontamination, cytology, genetics, single-cell analysis, cancer treatment, and other applications. On-chip EL is a promising technology for multiplexed automated implementation of cell-sample preparation and processing with micro- or nanoliter reagents.
Elliott, E. A.; Rodriguez, A. B.; McKee, B. A.
2017-12-01
Traditional models of estuarine systems show deposition occurs primarily within the central basin. There, accommodation space is high within the deep central valley, which is below regional wave base and where current energy is presumed to reach a relative minimum, promoting direct deposition of cohesive sediment and minimizing erosion. However, these models often reflect long-term (decadal-millennial) timescales, where accumulation rates are in relative equilibrium with the rate of relative sea-level rise, and lack the resolution to capture shorter term changes in sediment deposition and erosion within the central estuary. This work presents a conceptual model for estuarine sedimentation during non-equilibrium conditions, where high-energy inputs to the system reach a relative maximum in the central basin, resulting in temporary deposition and/or remobilization over sub-annual to annual timescales. As an example, we present a case study of Core Sound, NC, a lagoonal estuarine system where the regional base-level has been reached, and sediment deposition, resuspension and bypassing is largely a result of non-equilibrium, high-energy events. Utilizing a 465 cm-long sediment core from a mini-basin located between Core Sound and the continental shelf, a 40-year sub-annual chronology was developed for the system, with sediment accumulation rates (SAR) interpolated to a monthly basis over the 40-year record. This study links erosional processes in the estuary directly with sediment flux to the continental shelf, taking advantage of the highly efficient sediment trapping capability of the mini-basin. The SAR record indicates high variation in the estuarine sediment supply, with peaks in the SAR record at a recurrence interval of 1 year (+/- 0.25). This record has been compared to historical storm influence for the area. Through this multi-decadal record, sediment flushing events occur at a much more frequent interval than previously thought (i.e. annual rather than decadal timescales). This non-equilibrium estuarine model highlights moderate-energy events that impact the coast at least every year, in addition to high energy less frequent decadal to millennial events for modulating sediment and particulate matter erosion and transport through the estuary and delivery to the continental shelf.
Zöllner, Frank G; Daab, Markus; Sourbron, Steven P; Schad, Lothar R; Schoenberg, Stefan O; Weisser, Gerald
2016-01-14
Perfusion imaging has become an important image based tool to derive the physiological information in various applications, like tumor diagnostics and therapy, stroke, (cardio-) vascular diseases, or functional assessment of organs. However, even after 20 years of intense research in this field, perfusion imaging still remains a research tool without a broad clinical usage. One problem is the lack of standardization in technical aspects which have to be considered for successful quantitative evaluation; the second problem is a lack of tools that allow a direct integration into the diagnostic workflow in radiology. Five compartment models, namely, a one compartment model (1CP), a two compartment exchange (2CXM), a two compartment uptake model (2CUM), a two compartment filtration model (2FM) and eventually the extended Toft's model (ETM) were implemented as plugin for the DICOM workstation OsiriX. Moreover, the plugin has a clean graphical user interface and provides means for quality management during the perfusion data analysis. Based on reference test data, the implementation was validated against a reference implementation. No differences were found in the calculated parameters. We developed open source software to analyse DCE-MRI perfusion data. The software is designed as plugin for the DICOM Workstation OsiriX. It features a clean GUI and provides a simple workflow for data analysis while it could also be seen as a toolbox providing an implementation of several recent compartment models to be applied in research tasks. Integration into the infrastructure of a radiology department is given via OsiriX. Results can be saved automatically and reports generated automatically during data analysis ensure certain quality control.
Lerner, Itamar; Bentin, Shlomo; Shriki, Oren
2012-01-01
Localist models of spreading activation (SA) and models assuming distributed representations offer very different takes on semantic priming, a widely investigated paradigm in word recognition and semantic memory research. In this study, we implemented SA in an attractor neural network model with distributed representations and created a unified…
Energy Technology Data Exchange (ETDEWEB)
Cina, Jeffrey A., E-mail: cina@uoregon.edu; Kovac, Philip A. [Department of Chemistry and Biochemistry, and Oregon Center for Optical, Molecular, and Quantum Science, University of Oregon, Eugene, Oregon 97403 (United States); Jumper, Chanelle C. [Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6 (Canada); Dean, Jacob C.; Scholes, Gregory D., E-mail: gscholes@princeton.edu [Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)
2016-05-07
We rebuild the theory of ultrafast transient-absorption/transmission spectroscopy starting from the optical response of an individual molecule to incident femtosecond pump and probe pulses. The resulting description makes use of pulse propagators and free molecular evolution operators to arrive at compact expressions for the several contributions to a transient-absorption signal. In this alternative description, which is physically equivalent to the conventional response-function formalism, these signal contributions are conveniently expressed as quantum mechanical overlaps between nuclear wave packets that have undergone different sequences of pulse-driven optical transitions and time-evolution on different electronic potential-energy surfaces. Using this setup in application to a simple, multimode model of the light-harvesting chromophores of PC577, we develop wave-packet pictures of certain generic features of ultrafast transient-absorption signals related to the probed-frequency dependence of vibrational quantum beats. These include a Stokes-shifting node at the time-evolving peak emission frequency, antiphasing between vibrational oscillations on opposite sides (i.e., to the red or blue) of this node, and spectral fingering due to vibrational overtones and combinations. Our calculations make a vibrationally abrupt approximation for the incident pump and probe pulses, but properly account for temporal pulse overlap and signal turn-on, rather than neglecting pulse overlap or assuming delta-function excitations, as are sometimes done.
Calvo, N.; Garcia, R. R.; Kinnison, D. E.
2017-04-01
The latest version of the Whole Atmosphere Community Climate Model (WACCM), which includes a new chemistry scheme and an updated parameterization of orographic gravity waves, produces temperature trends in the Antarctic lower stratosphere in excellent agreement with radiosonde observations for 1969-1998 as regards magnitude, location, timing, and persistence. The maximum trend, reached in November at 100 hPa, is -4.4 ± 2.8 K decade-1, which is a third smaller than the largest trend in the previous version of WACCM. Comparison with a simulation without the updated orographic gravity wave parameterization, together with analysis of the model's thermodynamic budget, reveals that the reduced trend is due to the effects of a stronger Brewer-Dobson circulation in the new simulations, which warms the polar cap. The effects are both direct (a trend in adiabatic warming in late spring) and indirect (a smaller trend in ozone, hence a smaller reduction in shortwave heating, due to the warmer environment).
Hossack, Blake R.; Honeycutt, Richard
2017-01-01
Drought has fueled an increased frequency and severity of large wildfires in many ecosystems. Despite an increase in research on wildfire effects on vertebrates, the vast majority of it has focused on short-term (effects and there is still little information on the time scale of population recovery for species that decline in abundance after fire. In 2003, a large wildfire in Montana (USA) burned the watersheds of four of eight streams that we sampled for larval Rocky Mountain tailed frogs (Ascaphus montanus) in 2001. Surveys during 2004–2005 revealed reduced abundance of larvae in burned streams relative to unburned streams, with greater declines associated with increased fire extent. Rocky Mountain tailed frogs have low vagility and have several unusual life-history traits that could slow population recovery, including an extended larval period (4 years), delayed sexual maturity (6–8 years), and low fecundity (negative effects of burn extent on larval abundance weakened> 58% within 12 years after the fire. We also found moderate synchrony among populations in unburned streams and negative spatial autocorrelation among populations in burned streams. We suspect negative spatial autocorrelation among spatially-clustered burned streams reflected increased post-fire patchiness in resources and different rates of local recovery. Our results add to a growing body of work that suggests populations in intact ecosystems tend to be resilient to habitat changes caused by wildfire. Our results also provide important insights into recovery times of populations that have been negatively affected by severe wildfire.
International Nuclear Information System (INIS)
Zöllner, Frank G.; Daab, Markus; Sourbron, Steven P.; Schad, Lothar R.; Schoenberg, Stefan O.; Weisser, Gerald
2016-01-01
Perfusion imaging has become an important image based tool to derive the physiological information in various applications, like tumor diagnostics and therapy, stroke, (cardio-) vascular diseases, or functional assessment of organs. However, even after 20 years of intense research in this field, perfusion imaging still remains a research tool without a broad clinical usage. One problem is the lack of standardization in technical aspects which have to be considered for successful quantitative evaluation; the second problem is a lack of tools that allow a direct integration into the diagnostic workflow in radiology. Five compartment models, namely, a one compartment model (1CP), a two compartment exchange (2CXM), a two compartment uptake model (2CUM), a two compartment filtration model (2FM) and eventually the extended Toft’s model (ETM) were implemented as plugin for the DICOM workstation OsiriX. Moreover, the plugin has a clean graphical user interface and provides means for quality management during the perfusion data analysis. Based on reference test data, the implementation was validated against a reference implementation. No differences were found in the calculated parameters. We developed open source software to analyse DCE-MRI perfusion data. The software is designed as plugin for the DICOM Workstation OsiriX. It features a clean GUI and provides a simple workflow for data analysis while it could also be seen as a toolbox providing an implementation of several recent compartment models to be applied in research tasks. Integration into the infrastructure of a radiology department is given via OsiriX. Results can be saved automatically and reports generated automatically during data analysis ensure certain quality control
Directory of Open Access Journals (Sweden)
Rangga Restu Prayogo
2016-12-01
Full Text Available The purpose of this research is to study the relationship among destination image, service quality, e-WOM, and revisit intentions in the tourism industry. A questionnaire given to tourists who visit one of the farrest island in western part of Indonesia, Sabang Island and using sampling through the convenience sampling. A structural equation model (SEM test with WarpPLS 3.0 was used to test the relationship between research variables. This research gathered from 150 respondents. The empirical results from PLS-SEM showed that; the destination image positive affect e-WOM and revisit intention; service quality affect e-WOM and revisit intention; e-WOM positive affect to revisit intention tourists. The implications and future research issues were discussed.
Directory of Open Access Journals (Sweden)
Febry Adhiana
2008-03-01
Findin s: There are no differences between private and public hospitals in service quality, patient satisf Um and patient revisit intention. Finally the implications of the results are highlighted for health :are managers.
BAEK, Seung Jin
2017-01-01
Abstract. This paper examines whether rising income inequality is the stylised fact for the process of structural transformation by revisiting classical accounts on the transformation-inequality nexus, with a particular focus on Kuznets’s and Rostow’s theories of development and Rawls’s difference principle. In addition, a complex interaction between structural transformation and income inequality is analysed by exploring the multi-dimensions of inequality dynamics to link Kuznets-Rostow-Rawl...
Revisiting System Paradigms from the Viewpoint of Manufacturing Sustainability
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Zhuming Bi
2011-08-01
Full Text Available A system paradigm is an abstract representation of system; it includes system architecture used to determine the types and numbers of components and their relations in the system. The design of system paradigm relies on customers’ requirements and the characteristics of the manufacturing environment. Many system paradigms and design guidelines have been proposed for a variety of customers’ needs including functions, cost, quality, personalization, and lead time of products. However, the consideration of sustainability becomes essential to today’s manufacturing systems; a new challenge is how to evolve existing paradigms to accommodate the requirements of sustainability. In contrast to ample research activities on system paradigms in past decades, recent studies on system paradigms have been restricted, partially due to unclear research directions. Limited works can be found on conceiving new manufacturing system paradigms from the perspective of sustainability; most of the related literature concerns the new requirements of sustainability. The objectives of this work are (i to examine the requirements of manufacturing systems in a wider scope; (ii to revisit existing paradigms to clarify their limitations and bottlenecks; and eventually (iii to identify some research directions, which will lead to a solution of sustainable manufacturing. To achieve these objectives, firstly, a brief description of today’s manufacturing environment is provided. Secondly, the requirements of sustainability are discussed, and the relevant researches on system sustainability are surveyed. Thirdly, the reconfigurable system paradigm is focused, and the gaps between a reconfigurable manufacturing system and a sustainable manufacturing system are discussed. Finally, the future endeavors towards to the next-generation manufacturing system paradigms are discussed.
The Lumbar Lordosis in Males and Females, Revisited.
Directory of Open Access Journals (Sweden)
Ori Hay
Full Text Available Whether differences exist in male and female lumbar lordosis has been debated by researchers who are divided as to the nature of variations in the spinal curve, their origin, reasoning, and implications from a morphological, functional and evolutionary perspective. Evaluation of the spinal curvature is constructive in understanding the evolution of the spine, as well as its pathology, planning of surgical procedures, monitoring its progression and treatment of spinal deformities. The aim of the current study was to revisit the nature of lumbar curve in males and females.Our new automated method uses CT imaging of the spine to measure lumbar curvature in males and females. The curves extracted from 158 individuals were based on the spinal canal, thus avoiding traditional pitfalls of using bone features for curve estimation. The model analysis was carried out on the entire curve, whereby both local and global descriptors were examined in a single framework. Six parameters were calculated: segment length, curve length, curvedness, lordosis peak location, lordosis cranial peak height, and lordosis caudal peak height.Compared to males, the female spine manifested a statistically significant greater curvature, a caudally located lordotic peak, and greater cranial peak height. As caudal peak height is similar for males and females, the illusion of deeper lordosis among females is due partially to the fact that the upper part of the female lumbar curve is positioned more dorsally (more backwardly inclined.Males and females manifest different lumbar curve shape, yet similar amount of inward curving (lordosis. The morphological characteristics of the female spine were probably developed to reduce stress on the vertebral elements during pregnancy and nursing.
The Lumbar Lordosis in Males and Females, Revisited.
Hay, Ori; Dar, Gali; Abbas, Janan; Stein, Dan; May, Hila; Masharawi, Youssef; Peled, Nathan; Hershkovitz, Israel
2015-01-01
Whether differences exist in male and female lumbar lordosis has been debated by researchers who are divided as to the nature of variations in the spinal curve, their origin, reasoning, and implications from a morphological, functional and evolutionary perspective. Evaluation of the spinal curvature is constructive in understanding the evolution of the spine, as well as its pathology, planning of surgical procedures, monitoring its progression and treatment of spinal deformities. The aim of the current study was to revisit the nature of lumbar curve in males and females. Our new automated method uses CT imaging of the spine to measure lumbar curvature in males and females. The curves extracted from 158 individuals were based on the spinal canal, thus avoiding traditional pitfalls of using bone features for curve estimation. The model analysis was carried out on the entire curve, whereby both local and global descriptors were examined in a single framework. Six parameters were calculated: segment length, curve length, curvedness, lordosis peak location, lordosis cranial peak height, and lordosis caudal peak height. Compared to males, the female spine manifested a statistically significant greater curvature, a caudally located lordotic peak, and greater cranial peak height. As caudal peak height is similar for males and females, the illusion of deeper lordosis among females is due partially to the fact that the upper part of the female lumbar curve is positioned more dorsally (more backwardly inclined). Males and females manifest different lumbar curve shape, yet similar amount of inward curving (lordosis). The morphological characteristics of the female spine were probably developed to reduce stress on the vertebral elements during pregnancy and nursing.
"Research on Infertility: Definition Makes a Difference" Revisited.
Jacobson, Melanie H; Chin, Helen B; Mertens, Ann C; Spencer, Jessica B; Fothergill, Amy; Howards, Penelope P
2018-02-01
In a 1989 paper, Marchbanks et al. (Am J Epidemiol. 1989;130(2):259-267) noted inconsistent definitions of infertility across research and clinical practice and examined differences in prevalence estimates across definitions. Since their study, there have been substantial changes in society, technology, and clinical practice related to female reproductive health. In response, we revisited the original paper using data from a recent study among reproductive-aged women. Internal comparisons across various definitions of infertility were made by assessing how many and which women were classified as infertile, their age at infertility, and the probability of spontaneous pregnancy after infertility. Results were also compared with Marchbanks et al. Black women were more likely to be classified as infertile than white women based on the definition "12 months of unprotected intercourse" (40.1% vs. 33.7%) but less likely by "12 months of attempting pregnancy" (14.3% vs. 21.8%) and "visiting a doctor for help getting pregnant" (8.4% vs. 19.7%). After unprotected intercourse for 12 months, 36.1% of women who were attempting pregnancy spontaneously conceived by 6 months compared with 13.5% of women who were not attempting pregnancy. While our results for most infertility definitions were similar to those of Marchbanks et al., prevalence estimates continued to differ across demographic groups by definition. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
LARGE-SCALE FILAMENTARY STRUCTURES AROUND THE VIRGO CLUSTER REVISITED
Energy Technology Data Exchange (ETDEWEB)
Kim, Suk; Rey, Soo-Chang; Lee, Youngdae; Lee, Woong; Chung, Jiwon [Department of Astronomy and Space Science, Chungnam National University, 99 Daehak-ro, Daejeon 305-764 (Korea, Republic of); Bureau, Martin [Sub-department of Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Yoon, Hyein; Chung, Aeree [Department of Astronomy and Yonsei University Observatory, Yonsei University, Seoul 120-749 (Korea, Republic of); Jerjen, Helmut [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Lisker, Thorsten [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg (ZAH), Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Jeong, Hyunjin; Sung, Eon-Chang, E-mail: screy@cnu.ac.kr, E-mail: star4citizen@kasi.re.kr [Korea Astronomy and Space Science institute, 776 Daedeokdae-ro, Daejeon 305-348 (Korea, Republic of)
2016-12-20
We revisit the filamentary structures of galaxies around the Virgo cluster, exploiting a larger data set, based on the HyperLeda database, than previous studies. In particular, this includes a large number of low-luminosity galaxies, resulting in better sampled individual structures. We confirm seven known structures in the distance range 4 h {sup −1} Mpc < SGY < 16 h {sup −1} Mpc, now identified as filaments, where SGY is the axis of the supergalactic coordinate system roughly along the line of sight. The Hubble diagram of the filament galaxies suggests they are infalling toward the main body of the Virgo cluster. We propose that the collinear distribution of giant elliptical galaxies along the fundamental axis of the Virgo cluster is smoothly connected to two of these filaments (Leo II A and B). Behind the Virgo cluster (16 h {sup −1} Mpc < SGY < 27 h {sup −1} Mpc), we also identify a new filament elongated toward the NGC 5353/4 group (“NGC 5353/4 filament”) and confirm a sheet that includes galaxies from the W and M clouds of the Virgo cluster (“W–M sheet”). In the Hubble diagram, the NGC 5353/4 filament galaxies show infall toward the NGC 5353/4 group, whereas the W–M sheet galaxies do not show hints of gravitational influence from the Virgo cluster. The filamentary structures identified can now be used to better understand the generic role of filaments in the build-up of galaxy clusters at z ≈ 0.
What are 'Think Tanks'? Revisiting the Dilemma of the Definition
Directory of Open Access Journals (Sweden)
Juliana Cristina Rosa Hauck
2017-08-01
Full Text Available 'Think tanks' (TTs are 'sui generis' organizations that have been proliferating, playing more and more the role of very relevant actors on the political scene in clashes over interests, preferences and ideas for the formation of public policies. The definition of 'think tank', however, creates a conceptual gap that causes serious limitations on the development of this field of study. Excessive generality or inflexibility in the use of the concept raises questions about the validity of the category. Either way, the 'trade offs' of the conceptual choices have delineated a not very useful concept of think tank to both inter-contextual and inter-organizational comparability and to differentiate think thanks from overlapping organizations. The article revisits some of these dilemmas. To do so, the treatment in the specialized literature of the analytic category, highlighting both the insensitivity of the traditional North American matrix to different national contexts and its obsolescence to the changes in the context of TTs' action, including their own context of origin, is explained. In shedding light on promising conceptual contributions, the main contribution of the present article is the proposal of the radial structuring of the concept of think tanks as 'boundary spanners', as advanced by Medvetz, and of corresponding indicators to deal with the large variation in the substantive properties of the operationalization of the adopted concept. Thus, the aim is to reduce non-specificities in the analytic category and the dissent of its social significance, which demands less abstraction facing the exploratory state of the field of study.
Revisiting four scientific debates in ocean acidification research
Directory of Open Access Journals (Sweden)
A. J. Andersson
2012-03-01
Full Text Available In recent years, ocean acidification has gained continuously increasing attention from scientists and a number of stakeholders and has raised serious concerns about its effects on marine organisms and ecosystems. With the increase in interest, funding resources, and the number of scientific investigations focusing on this environmental problem, increasing amounts of data and results have been produced, and a progressively growing and more rigorous understanding of this problem has begun to develop. Nevertheless, there are still a number of scientific debates, and in some cases misconceptions, that keep reoccurring at a number of forums in various contexts. In this article, we revisit four of these topics that we think require further thoughtful consideration including: (1 surface seawater CO_{2} chemistry in shallow water coastal areas, (2 experimental manipulation of marine systems using CO_{2} gas or by acid addition, (3 net versus gross calcification and dissolution, and (4 CaCO_{3} mineral dissolution and seawater buffering. As a summation of these topics, we emphasize that: (1 many coastal environments experience seawater pCO_{2} that is significantly higher than expected from equilibrium with the atmosphere and is strongly linked to biological processes; (2 addition of acid, base or CO_{2} gas to seawater can all be useful techniques to manipulate seawater chemistry in ocean acidification experiments; (3 estimates of calcification or CaCO_{3} dissolution based on present techniques are measuring the net of gross calcification and dissolution; and (4 dissolution of metastable carbonate mineral phases will not produce sufficient alkalinity to buffer the pH and carbonate saturation state of shallow water environments on timescales of decades to hundreds of years to the extent that any potential negative effects on marine calcifiers will be avoided.
Guarana: revisiting a highly caffeinated plant from the Amazon.
Schimpl, Flávia Camila; da Silva, José Ferreira; Gonçalves, José Francisco de Carvalho; Mazzafera, Paulo
2013-10-28
Guarana (Paullinia cupana Kunth var. sorbilis (Mart.) Ducke) has been traditionally consumed by indigenous communities of the Amazon region. It is valued mainly for its stimulant property because of its high content of caffeine, which can be up to 6% in the seeds. The purpose of this review is to revisit this typically Brazilian plant, addressing economic considerations, the chemical makeup of the seeds and pharmacological properties so far investigated. Guarana is primarily produced in the Brazilian states of Amazonas and Bahia, and approximately 70% of the production is used by the industry of soft and energy drinks. The other 30% becomes guarana powder for direct consumption in capsules or dilution in water, or it serves as a raw material for the pharmaceutical and cosmetics industries. In addition to its stimulant property, guarana has other therapeutic properties, which have aroused the interest of the scientific community. This review shows that other guarana properties may be explored and how scarce are the studies regarding agronomic, plant pathology, physiology and breeding. So far, caffeine has been the main reason to study guarana and still will lead the researches because the demand for this alkaloid by food and pharmaceutical industry, and a strongly growing market related with beauty products. However, guarana has other components and there is great interest in studies designed to elucidate the effects of guarana's bioactive components and their potential pharmacological applications. Significant part of the guarana production in Brazil still comes from Indians tribes in the Amazon State, and any improvement in this plant, in any aspect, may propitiate a positive economic impact in their lives. © 2013 Elsevier Ireland Ltd. All rights reserved.
Ecological caring-Revisiting the original ideas of caring science.
Dahlberg, Helena; Ranheim, Albertine; Dahlberg, Karin
2016-01-01
The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew . Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it.
Ecological caring—Revisiting the original ideas of caring science
Directory of Open Access Journals (Sweden)
Helena Dahlberg
2016-11-01
Full Text Available The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew. Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it.
Ecological caring—Revisiting the original ideas of caring science
Dahlberg, Helena; Ranheim, Albertine; Dahlberg, Karin
2016-01-01
The aim of this empirically grounded philosophical paper is to explore the notion of holistic care with the intention to expand it into a notion of ecological care and in such a way revisit the original ideas of caring science. The philosophical analysis, driven by lifeworld theory and especially Merleau-Ponty's philosophy, is firmly rooted in contemporary clinical care. We used interview data from patients in a study at an anthroposophic clinic in Sweden, which forms part of an ecological community with, for example, ecological agriculture. The empirical study is analysed according to reflective lifeworld research. Starting from the fact that illness can be defined as a loss of homelikeness in the body and in the familiar world, our findings illustrate how ecological care helps the patient to once again find one's place in a world that is characterized by interconnectedness. The task of ecological care is thus not only to see the patient within a world of relationships but to help the patient find his/her place again, to understand himself/herself and the world anew. Ecological care is not only about fighting an illness, but also recognizes a patient from inside a world that s/he is affected by and affects, that s/he is understood and understands from. Such care tries to restore this connection by making possible the rhythmical movement as well as the space in-between activity and rest, between being cared for and actively involving oneself in one's recovery and between closing oneself off from the world and once again going out into it. PMID:27914196
Topological fluid dynamics of interfacial flows
DEFF Research Database (Denmark)
Brøns, Morten
1994-01-01
The topological description of flows in the vicinity of a solid boundary, that is familiar from the aerodynamics literature, has recently been extended to the case of flow at a liquid–gas interface or a free surface by Lugt [Phys. Fluids 30, 3647 (1987)]. Lugt's work is revisited in a more general...... setting, including nonconstant curvature of the interface and gradients of surface tension, using tools of modern nonlinear dynamics. Bifurcations of the flow pattern occur at degenerate configurations. Using the theory of unfolding, this paper gives a complete description of the bifurcations that depend...... on terms up to the second order. The general theory of this paper is applied to the topology of streamlines during the breaking of a wave and to the flow below a stagnant surface film. Physics of Fluids is copyrighted by The American Institute of Physics....
Effective-Medium Models for Marine Gas Hydrates, Mallik Revisited
Terry, D. A.; Knapp, C. C.; Knapp, J. H.
2011-12-01
Hertz-Mindlin type effective-medium dry-rock elastic models have been commonly used for more than three decades in rock physics analysis, and recently have been applied to assessment of marine gas hydrate resources. Comparisons of several effective-medium models with derivative well-log data from the Mackenzie River Valley, Northwest Territories, Canada (i.e. Mallik 2L-38 and 5L-38) were made several years ago as part of a marine gas hydrate joint industry project in the Gulf of Mexico. The matrix/grain supporting model (one of the five models compared) was clearly a better representation of the Mallik data than the other four models (2 cemented sand models; a pore-filling model; and an inclusion model). Even though the matrix/grain supporting model was clearly better, reservations were noted that the compressional velocity of the model was higher than the compressional velocity measured via the sonic logs, and that the shear velocities showed an even greater discrepancy. Over more than thirty years, variations of Hertz-Mindlin type effective medium models have evolved for unconsolidated sediments and here, we briefly review their development. In the past few years, the perfectly smooth grain version of the Hertz-Mindlin type effective-medium model has been favored over the infinitely rough grain version compared in the Gulf of Mexico study. We revisit the data from the Mallik wells to review assertions that effective-medium models with perfectly smooth grains are a better predictor than models with infinitely rough grains. We briefly review three Hertz-Mindlin type effective-medium models, and standardize nomenclature and notation. To calibrate the extended effective-medium model in gas hydrates, we use a well accepted framework for unconsolidated sediments through Hashin-Shtrikman bounds. We implement the previously discussed effective-medium models for saturated sediments with gas hydrates and compute theoretical curves of seismic velocities versus gas hydrate
The Angular Momentum of Baryons and Dark Matter Halos Revisited
Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan
2011-01-01
Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated
Revisited Inventory of Glaciers on Axel Heiberg Island, Nunavut
Thomson, L.; Osinski, G.
2009-05-01
As documented in the IPCC's Climate Change 2007 report, the high latitude regions of the Northern Hemisphere are experiencing the highest rates of warming. Given that 35% of the global glacial ice exists within the Arctic Archipelago, this region provides an excellent laboratory for monitoring the anticipated degree of glacial recession [1]. Evidence of arctic warming through negative mass balance trends has been detected in several studies already [e.g., 2]. Here, we show the importance and value of historical records in the task of monitoring glacial retreat. A highly detailed inventory developed by S. Ommanney in 1969 [3], has been revisited and transformed into digital format for the purposes of integration with modern inventories. The Ommanney inventory covers the entirety of Axel Heiberg Island , NU, and includes details often lacking in present day inventories, including orientations (accumulation and ablation zones), elevations (highest, lowest, elevation of the snowline, and the mean elevations of both the accumulation and ablation areas), length (of the ablation area, exposed ice, and of the total glacier including debris cover), area (of the ablation area, exposed ice, and of the total glacier), accumulation area ratio (AAR), depth, volume, and a six digit code which gives qualitative details on glacier attributes. This report is one of the most thorough and comprehensive glacier inventory report ever published in Canada. More recent inventories used for comparison include the glacier extents created by the National Topographic System based on photography from 1980-1987, as well as extents developed by Dr. Luke Copland for the Global Land Ice Measurements from Space (GLIMS) database using 1999-2000 satellite imagery. Our preliminary results show that approximately 90% of ice bodies under 0.2km on Axel Heiberg Island have disappeared entirely in the 40 year period of interest. The issue of glacier definition will be discussed as a possible cause of these
International Nuclear Information System (INIS)
Kim, Do Hun; Mun, Tae Hun; Kim, Dong Hwan
1999-02-01
This book introduces systems thinking and conceptual tool and modeling tool of dynamics system such as tragedy of single thinking, accessible way of system dynamics, feedback structure and causal loop diagram analysis, basic of system dynamics modeling, causal loop diagram and system dynamics modeling, information delay modeling, discovery and application for policy, modeling of crisis of agricultural and stock breeding products, dynamic model and lesson in ecosystem, development and decadence of cites and innovation of education forward system thinking.
International Nuclear Information System (INIS)
Rogister, A.L.
1999-01-01
'Subneoclassical' heat fluxes are predicted in the high collisionality regime by the revisited neoclassical theory, which includes the roles of Finite Larmor Radius effects and Inertia, that we published earlier. Unlike conventional neoclassical theory, the revisited theory further provides a non degenerate ambipolarity constraint which defines unambiguously the radial electric field. Together with the parallel momentum equation, the ambipolarity constraint leads, under some conditions, to radial electric field profiles with high negative shear akin to those observed in spontaneous edge transport barriers. The predictions of the theory are outlined, with emphasis laid on the interpretation of experimental results such as magnitude of the jumps, width of the shear layer, local scaling laws. Extension of the theory to triggered transitions and cold pulse propagation studies is suggested. (author)
The Time has come to Revisit Solvency Funding Rules
Directory of Open Access Journals (Sweden)
Norma Nielson
2018-02-01
was small, and so the rules were not an unacceptable burden. Those rich returns are gone. Now, that gap between valuations has grown dramatically. In B.C., for example, a recent analysis found that when using a going-concern evaluation, 75 per cent of 143 defined-benefit plans registered in the province in 2015 had at least 100-per-cent funding, while the median funding ratio was 124 per cent. Using a solvency model, the median funding ratio was instead estimated to be a much lower 85 per cent. Closing that gap would require onerous pension contributions. More importantly, the contributions it triggers might never be needed to cover benefits. Quebec is the first province to recognize that pension-funding rules need to be revisited and made more responsive, with new rules coming in that will reduce the unnecessary burden on employers while also adapting to changes in the economic environment. Ontario is showing signs that it will take steps in the same direction. Regulators everywhere should be revisiting pension rules to: remove the solvency-valuation requirement for well-funded plans, while allowing the regulator to assume a worst-case scenario in the uncommon case where they believe it to be warranted; to develop a method to rate the credit risk of a plan; to be less stringent and more realistic about plan liabilities (by allowing some types of liabilities to use a longer amortization period; but still restricting plan changes for underfunded plans. The result would not only reduce the cost and work of over-regulating well-funded, well-run plans, while freeing up cash . By reducing pressure on the cash flow for sponsors, and adding more flexibility, the policymakers will ultimately make defined-benefit pension plans more sustainable. They might even see defined-benefit plans making a comeback among employers who found heavy contributions enough to drive them out of the DB world.
Grammatical relations and grammatical categories in Malay; The Indonesian prefix meN- revisited
Directory of Open Access Journals (Sweden)
Johnny Tjia
2015-04-01
Full Text Available The lexical roots of Malay are flexible with regard to their grammatical categories, which presents a problem in providing grammatical evidence for their category determination. This paper attempts to propose the use of affixes as one way to deal with the issue. Data from Indonesian and Ambon (Malay language are among others given for clarification. The grammatical evidence from Indonesian active meN-, together with other affixes, are revisited as they can contribute to our understanding of the matter.
Grammatical Relations and Grammatical Categories in Malay; the Indonesian Prefix MeN- Revisited
Tjia, Johnny
2015-01-01
The lexical roots of Malay are flexible with regard to their grammatical categories, which presents a problem in providing grammatical evidence for their category determination. This paper attempts to propose the use of affixes as one way to deal with the issue. Data from Indonesian and Ambon (Malay) language are among others given for clarification. The grammatical evidence from Indonesian active meN-, together with other affixes, are revisited as they can contribute to our understanding of ...
Sembodo Herry C
2008-01-01
The purpose: of this study is to assess the relative influences of distributive (DJ), procedural (PJ), and interactional (Li) justice on customer satisfaction on service recovery and to examine the relationship between recovery satisfaction and subsequent customer relationships: trust, word-of-riwuth (WOM), and revisit intention. Methodology: On-site surveys were administered to collect data from insurance customer who bought, and experienced a service failure. Findings: The effect of D...
Jamal Jamilah; Abu Bakar Hassan
2017-01-01
Organizational credibility, the extent of which an organization as the source of messages is perceived as trustworthy and reliable, is one important aspect to determine organization’s survival. The perceived credibility of the messages will either strengthen or worsen an organization reputation. The primary objective of this paper is to revisit the concept of organizational credibility and its interaction with organizational outcomes such as organizational reputation. Based on the situational...
First-principles lattice-gas Hamiltonian revisited: O-Pd(100)
Kappus, Wolfgang
2016-01-01
The methodology of deriving an adatom lattice-gas Hamiltonian (LGH) from first principles (FP) calculations is revisited. Such LGH cluster expansions compute a large set of lateral pair-, trio-, quarto interactions by solving a set of linear equations modelling regular adatom configurations and their FP energies. The basic assumption of truncating interaction terms beyond fifth nearest neighbors does not hold when adatoms show longer range interactions, e.g. substrate mediated elastic interac...
Operator entanglement of two-qubit joint unitary operations revisited: Schmidt number approach
Energy Technology Data Exchange (ETDEWEB)
Xia, Hui-Zhi; Li, Chao; Yang, Qing; Yang, Ming, E-mail: mingyang@ahu.edu.cn [Key Laboratory of Opto-electronic Information Acquisition and Manipulation, Ministry of Education, School of Physics and Material Science, Anhui University Hefei (China); Cao, Zhuo-Liang [School of Electronic Information Engineering, Hefei Normal University (China)
2012-08-15
The operator entanglement of two-qubit joint unitary operations is revisited. The Schmidt number, an important attribute of a two-qubit unitary operation, may have connection with the entanglement measure of the unitary operator. We find that the entanglement measure of a two-qubit unitary operators is classified by the Schmidt number of the unitary operators. We also discuss the exact relation between the operator entanglement and the parameters of the unitary operator. (author)
Revisit boundary conditions for the self-adjoint angular flux formulation
Energy Technology Data Exchange (ETDEWEB)
Wang, Yaqi [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gleicher, Frederick N. [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-03-01
We revisit the boundary conditions for SAAF. We derived the equivalent parity variational form ready for coding up. The more rigorous approach of evaluating odd parity should be solving the odd parity equation coupled with the even parity. We proposed a symmetric reflecting boundary condition although neither positive definiteness nor even-odd decoupling is achieved. A simple numerical test verifies the validity of these boundary conditions.
An Improvement on LSB Matching and LSB Matching Revisited Steganography Methods
Qazanfari, Kazem; Safabakhsh, Reza
2017-01-01
The aim of the steganography methods is to communicate securely in a completely undetectable manner. LSB Matching and LSB Matching Revisited steganography methods are two general and esiest methods to achieve this aim. Being secured against first order steganalysis methods is the most important feature of these methods. On the other hand, these methods don't consider inter pixel dependency. Therefore, recently, several steganalysis methods are proposed that by using co-occurrence matrix detec...
Revisiting the description of Protein-Protein interfaces. Part II: Experimental study
Cazals , Frédéric; Proust , Flavien
2006-01-01
This paper provides a detailed experimental study of an interface model developed in the companion article F. Cazals and F. Proust, Revisiting the description of Protein-Protein interfaces. Part I: algorithms. Our experimental study is concerned with the usual database of protein-protein complexes, split into five families (Proteases, Immune system, Enzyme Complexes, Signal transduction, Misc.) Our findings, which bear some contradictions with usual statements are the following: (i)Connectivi...
Growth of the firm and foreign trade: Adrian Wood's theory revisited
Catermol, Fabrício
2006-01-01
This paper analyzes the growth of the firm by foreign trade. The theory of Adrian Wood is revisited for the analysis of growth and profit trade-off and improved to cope with growth by exports. The main outcome of this paper is that low domestic demand can be a very important factor to firm choices growth by foreign market. However, the growth of domestic demand does not necessarily reduce exports.
Revisit the spin-FET: Multiple reflection, inelastic scattering, and lateral size effects
Xu, Luting; Li, Xin-Qi; Sun, Qing-feng
2014-01-01
We revisit the spin-injected field effect transistor (spin-FET) by simulating a lattice model based on recursive lattice Green's function approach. In the one-dimensional case and coherent regime, the simulated results reveal noticeable differences from the celebrated Datta-Das model, which motivate thus an improved treatment and lead to analytic and generalized result. The simulation also allows us to address inelastic scattering (using B\\"uttiker's fictitious reservoir approach) and lateral...
Forecasting of Satisfaction and Revisit Intention of Indonesia Shoppers in Shopping Malls
Ayuni, Risca Fitri
2017-01-01
. Due to tight competition, changing value proposition of customer and shiftingof mall functions become center for leisure purposes, shopping mall developer mustfocus on create shopper satisfaction to influence their post-transaction behaviors. Thisstudy investigates the relationship between mall personality, self-congruity, perceivedquality, shopping value, shopper satisfaction and revisit intention. Two hundredrespondents participated in this study. In order to achieve the aim of this study...
Sarvari, Neda Gholizadeh
2012-01-01
ABSTRACT: This study revisits the previous studies carried out by several researchers on Customer – Based Brand Equity with an intension to further investigate the applications and testing of the Customer-Based Brand Equity (CBBE) model in relation to destination branding. The study specifically examines the effects of Brand Equity Dimensions (Brand Awareness, Brand Loyalty, Brand Value, Brand Quality and Brand Image) on Tourists Satisfaction and ultimately on Future Behaviours that result i...
Explaining tourists satisfaction and intention to revisit Nha Trang, Viet Nam
Tran, Thi Ai Cam
2011-01-01
The first purpose of the thesis is to find how visitors evaluate the quality of different facets or attributes of a destination image of Nha Trang, how satisfied they are with Nha Trang, loyalty intention to revisit and willingness to recommend Nha Trang to others. The second is to investigate what “image” is most important to explain global satisfaction with visiting Nha Trang. The third is to investigate how perceived quality, satisfaction and other motivational or dismotivational factors ...
Taï chimpanzees anticipate revisiting high-valued fruit trees from further distances.
Ban, Simone D; Boesch, Christophe; Janmaat, Karline R L
2014-11-01
The use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. However, the exact content of this memory is poorly known to date. This study investigated what specific information from previous feeding visits chimpanzees (Pan troglodytes verus), in Taï National Park, Côte d'Ivoire, take into account when they revisit the same feeding trees. By following five adult females for many consecutive days, we tested from what distance the females directed their travels towards previously visited feeding trees and how previous feeding experiences and fruit tree properties influenced this distance. To exclude the influence of sensory cues, the females' approach distance was measured from their last significant change in travel direction until the moment they entered the tree's maximum detection field. We found that chimpanzees travelled longer distances to trees at which they had previously made food grunts and had rejected fewer fruits compared to other trees. In addition, the results suggest that the chimpanzees were able to anticipate the amount of fruit that they would find in the trees. Overall, our findings are consistent with the hypothesis that chimpanzees act upon a retrieved memory of their last feeding experiences long before they revisit feeding trees, which would indicate a daily use of long-term prospective memory. Further, the results are consistent with the possibility that positive emotional experiences help to trigger prospective memory retrieval in forest areas that are further away and have fewer cues associated with revisited feeding trees.
Directory of Open Access Journals (Sweden)
Rian Andriani
2016-11-01
ABSTRACT Bogor Botanical Gardens is one of tourist destination in Bogor City, West Java, which the geographical in a strategic location between two big cities, Jakarta and Bandung. This location factor is can become an opportunity for Bogor Botanical Gardens to become a favorite tourist destination in Bogor City. Guide Performance and Quality Tourism Service is one of part of the tourism, so the researcher focus to Guide Performance and Quality Tourism Service To Revisit Intention in Bogor Botanical Gardens. In this research, the researcher used quantitative methode with descriptive verificative. The researcher used 100 respondent for a sample. In this research, the researcher used multiple linier regresion analysis with hypotesis test used determination coefficient test and F test. The classical assumption of this research is used normality test, multicollinearity test, heteroskedastisitas test and auto correlation test. In this research, the Guide Performance and Quality Tourism Service factors has an influence 33,2% of Revisit Intention in Bogor Botanical Garden. Keywords: Guide Performance, Quality Tourism Service and Revisit Intention
New insights in particle dynamics from group cohomology
International Nuclear Information System (INIS)
Aldaya, V; Jaramillo, J L; Guerrero, J
2002-01-01
The dynamics of a particle moving in background electromagnetic and gravitational fields is revisited from a Lie group cohomological perspective. Physical constants characterizing the particle appear as central extension parameters of a group which is obtained from a centrally extended kinematical group (Poincare or Galilei) by making some subgroup local. The corresponding dynamics is generated by a vector field inside the kernel of a pre-symplectic form which is derived from the canonical left-invariant 1-form on the extended group. A non-relativistic limit is derived from the geodesic motion via an Inoenue-Wigner contraction. A deeper analysis of the cohomological structure reveals the possibility of a new force associated with a non-trivial mixing of gravity and electromagnetism leading to, in principle, testable predictions. (letter to the editor)
Basic Coandă MAV Fluid Dynamics and Flight Mechanics
Djojodihardjo, H.; Ahmed, RI
2017-04-01
Capitalizing on the basic fundamental principles, the Fluid Dynamics and Flight Mechanics of a semi-spherical Coandă MAV configurations are revisited and analyzed as a baseline. A mathematical model for a spherical Coandă MAV in hover and translatory motion is developed and analyzed from first physical principles. To gain further insight into the prevailing flow field around a Coandă MAV, as well as to verify the theoretical prediction presented in the work, a computational fluid dynamic CFD simulations for a Coandă MAV generic model are elaborated. The mathematical model and derived performance measures are shown to be capable in describing the physical phenomena of the flow field of the semi-spherical Coandă MAV. The relationships between the relevant parameters of the mathematical model of the Coandă MAV to the forces acting on it are elaborated subsequently.
Dynamical quantum phase transitions in extended transverse Ising models
Bhattacharjee, Sourav; Dutta, Amit
2018-04-01
We study the dynamical quantum phase transitions (DQPTs) manifested in the subsequent unitary dynamics of an extended Ising model with an additional three spin interactions following a sudden quench. Revisiting the equilibrium phase diagram of the model, where different quantum phases are characterized by different winding numbers, we show that in some situations the winding number may not change across a gap closing point in the energy spectrum. Although, usually there exists a one-to-one correspondence between the change in winding number and the number of critical time scales associated with DQPTs, we show that the extended nature of interactions may lead to unusual situations. Importantly, we show that in the limit of the cluster Ising model, three critical modes associated with DQPTs become degenerate, thereby leading to a single critical time scale for a given sector of Fisher zeros.
Reformulation of a stochastic action principle for irregular dynamics
International Nuclear Information System (INIS)
Wang, Q.A.; Bangoup, S.; Dzangue, F.; Jeatsa, A.; Tsobnang, F.; Le Mehaute, A.
2009-01-01
A stochastic action principle for random dynamics is revisited. Numerical diffusion experiments are carried out to show that the diffusion path probability depends exponentially on the Lagrangian action A=∫ a b Ldt. This result is then used to derive the Shannon measure for path uncertainty. It is shown that the maximum entropy principle and the least action principle of classical mechanics can be unified into δA-bar=0 where the average is calculated over all possible paths of the stochastic motion between two configuration points a and b. It is argued that this action principle and the maximum entropy principle are a consequence of the mechanical equilibrium condition extended to the case of stochastic dynamics.
International Nuclear Information System (INIS)
Bruno, J.; Duro, L.; Jordana, S.; Cera, E.
1996-02-01
Solubility limits constitute a critical parameter for the determination of the mobility of radionuclides in the near field and the geosphere, and consequently for the performance assessment of nuclear waste repositories. Mounting evidence from natural system studies indicate that trace elements, and consequently radionuclides, are associated to the dynamic cycling of major geochemical components. We have recently developed a thermodynamic approach to take into consideration the co-precipitation and co-dissolution processes that mainly control this linkage. The approach has been tested in various natural system studies with encouraging results. The Pocos de Caldas natural analogue was one of the sites where a full testing of our predictive geochemical modelling capabilities were done during the analogue project. We have revisited the Pocos de Caldas data and expanded the trace element solubility calculations by considering the documented trace metal/major ion interactions. This has been done by using the co-precipitation/co-dissolution approach. The outcome is as follows: A satisfactory modelling of the behaviour of U, Zn and REEs is achieved by assuming co-precipitation with ferrihydrite. Strontium concentrations are apparently controlled by its co-dissolution from Sr-rich fluorites. From the performance assessment point of view, the present work indicates that calculated solubility limits using the co-precipitation approach are in close agreement with the actual trace element concentrations. Furthermore, the calculated radionuclide concentrations are 2-4 orders of magnitude lower than conservative solubility limits calculated by assuming equilibrium with individual trace element phases. 34 refs, 18 figs, 13 tabs
Energy Technology Data Exchange (ETDEWEB)
Bruno, J.; Duro, L.; Jordana, S.; Cera, E. [QuantiSci, Barcelona (Spain)
1996-02-01
Solubility limits constitute a critical parameter for the determination of the mobility of radionuclides in the near field and the geosphere, and consequently for the performance assessment of nuclear waste repositories. Mounting evidence from natural system studies indicate that trace elements, and consequently radionuclides, are associated to the dynamic cycling of major geochemical components. We have recently developed a thermodynamic approach to take into consideration the co-precipitation and co-dissolution processes that mainly control this linkage. The approach has been tested in various natural system studies with encouraging results. The Pocos de Caldas natural analogue was one of the sites where a full testing of our predictive geochemical modelling capabilities were done during the analogue project. We have revisited the Pocos de Caldas data and expanded the trace element solubility calculations by considering the documented trace metal/major ion interactions. This has been done by using the co-precipitation/co-dissolution approach. The outcome is as follows: A satisfactory modelling of the behaviour of U, Zn and REEs is achieved by assuming co-precipitation with ferrihydrite. Strontium concentrations are apparently controlled by its co-dissolution from Sr-rich fluorites. From the performance assessment point of view, the present work indicates that calculated solubility limits using the co-precipitation approach are in close agreement with the actual trace element concentrations. Furthermore, the calculated radionuclide concentrations are 2-4 orders of magnitude lower than conservative solubility limits calculated by assuming equilibrium with individual trace element phases. 34 refs, 18 figs, 13 tabs.
Relativistic dynamics of point magnetic moment
Rafelski, Johann; Formanek, Martin; Steinmetz, Andrew
2018-01-01
The covariant motion of a classical point particle with magnetic moment in the presence of (external) electromagnetic fields is revisited. We are interested in understanding extensions to the Lorentz force involving point particle magnetic moment (Stern-Gerlach force) and how the spin precession dynamics is modified for consistency. We introduce spin as a classical particle property inherent to Poincaré symmetry of space-time. We propose a covariant formulation of the magnetic force based on a `magnetic' 4-potential and show how the point particle magnetic moment relates to the Amperian (current loop) and Gilbertian (magnetic monopole) descriptions. We show that covariant spin precession lacks a unique form and discuss the connection to g-2 anomaly. We consider the variational action principle and find that a consistent extension of the Lorentz force to include magnetic spin force is not straightforward. We look at non-covariant particle dynamics, and present a short introduction to the dynamics of (neutral) particles hit by a laser pulse of arbitrary shape.
Opinion dynamics on an adaptive random network
Benczik, I. J.; Benczik, S. Z.; Schmittmann, B.; Zia, R. K. P.
2009-04-01
We revisit the classical model for voter dynamics in a two-party system with two basic modifications. In contrast to the original voter model studied in regular lattices, we implement the opinion formation process in a random network of agents in which interactions are no longer restricted by geographical distance. In addition, we incorporate the rapidly changing nature of the interpersonal relations in the model. At each time step, agents can update their relationships. This update is determined by their own opinion, and by their preference to make connections with individuals sharing the same opinion, or rather with opponents. In this way, the network is built in an adaptive manner, in the sense that its structure is correlated and evolves with the dynamics of the agents. The simplicity of the model allows us to examine several issues analytically. We establish criteria to determine whether consensus or polarization will be the outcome of the dynamics and on what time scales these states will be reached. In finite systems consensus is typical, while in infinite systems a disordered metastable state can emerge and persist for infinitely long time before consensus is reached.
Relativistic dynamics of point magnetic moment
Energy Technology Data Exchange (ETDEWEB)
Rafelski, Johann; Formanek, Martin; Steinmetz, Andrew [The University of Arizona, Department of Physics, Tucson, AZ (United States)
2018-01-15
The covariant motion of a classical point particle with magnetic moment in the presence of (external) electromagnetic fields is revisited. We are interested in understanding extensions to the Lorentz force involving point particle magnetic moment (Stern-Gerlach force) and how the spin precession dynamics is modified for consistency. We introduce spin as a classical particle property inherent to Poincare symmetry of space-time. We propose a covariant formulation of the magnetic force based on a 'magnetic' 4-potential and show how the point particle magnetic moment relates to the Amperian (current loop) and Gilbertian (magnetic monopole) descriptions. We show that covariant spin precession lacks a unique form and discuss the connection to g - 2 anomaly. We consider the variational action principle and find that a consistent extension of the Lorentz force to include magnetic spin force is not straightforward. We look at non-covariant particle dynamics, and present a short introduction to the dynamics of (neutral) particles hit by a laser pulse of arbitrary shape. (orig.)
Tales of sociology and the nursing curriculum: revisiting the debates.
Aranda, Kay; Law, Kate
2007-08-01
. Sociology and the nursing curriculum; editorial. Nurse Education in Practice 4, 81-82; Mowforth, G., Harrison, J., Morris, M., 2005. An investigation into adult nursing students' experience of the relevance and application of behavioural sciences (biology, psychology and sociology) across two different curricula. Nurse Education Today 25, 41-48]. Much attention has been given to the role, utility and value of sociology mostly within pre-registration but also post-registration nursing curricula. Through an initial analysis of a series of letters appearing in The Nursing Times over a 12 week period in 2004, and using an analytical framework of four tales (realist, critical, deconstructive and reflexive) we revisit this relationship. Unlike previous debates our argument is that this relationship is more usefully viewed as emblematic of the legitimation crisis inherent in all modern projects. We argue that in order to move beyond the 'utility' discussion, an interrogation of the knowledge claims of both nursing and sociology is required.
Increased 30-Day Emergency Department Revisits Among Homeless Patients with Mental Health Conditions
Directory of Open Access Journals (Sweden)
Chun Nok Lam
2016-09-01
Full Text Available Introduction: Patients with mental health conditions frequently use emergency medical services. Many suffer from substance use and homelessness. If they use the emergency department (ED as their primary source of care, potentially preventable frequent ED revisits and hospital readmissions can worsen an already crowded healthcare system. However, the magnitude to which homelessness affects health service utilization among patients with mental health conditions remains unclear in the medical community. This study assessed the impact of homelessness on 30-day ED revisits and hospital readmissions among patients presenting with mental health conditions in an urban, safety-net hospital. Methods: We conducted a secondary analysis of administrative data on all adult ED visits in 2012 in an urban safety-net hospital. Patient demographics, mental health status, homelessness, insurance coverage, level of acuity, and ED disposition per ED visit were analyzed using multilevel modeling to control for multiple visits nested within patients. We performed multivariate logistic regressions to evaluate if homelessness moderated the likelihood of mental health patients’ 30-day ED revisits and hospital readmissions. Results: Study included 139,414 adult ED visits from 92,307 unique patients (43.5±15.1 years, 51.3% male, 68.2% Hispanic/Latino. Nearly 8% of patients presented with mental health conditions, while 4.6% were homeless at any time during the study period. Among patients with mental health conditions, being homeless contributed to an additional 28.0% increase in likelihood (4.28 to 5.48 odds of 30-day ED revisits and 38.2% increase in likelihood (2.04 to 2.82 odds of hospital readmission, compared to non-homeless, non-mental health (NHNM patients as the base category. Adjusted predicted probabilities showed that homeless patients presenting with mental health conditions have a 31.1% chance of returning to the ED within 30-day post discharge and a 3
Xie, Huimin
The following sections are included: * Definition of Dynamical Languages * Distinct Excluded Blocks * Definition and Properties * L and L″ in Chomsky Hierarchy * A Natural Equivalence Relation * Symbolic Flows * Symbolic Flows and Dynamical Languages * Subshifts of Finite Type * Sofic Systems * Graphs and Dynamical Languages * Graphs and Shannon-Graphs * Transitive Languages * Topological Entropy
International Nuclear Information System (INIS)
Balazs, N.L.
1979-01-01
It is pointed out that in semiclassical dynamics one is encouraged to study the evolution of those curves in phase space which classically represent ensembles corresponding to wave functions. It is shown that the fixed points generate new time scales so that for times longer than the critical times, quantum dynamics will profoundly differ from classical dynamics. (P.L.)
Revisiting the issue of elite capture in participatory initiatives
DEFF Research Database (Denmark)
Lund, Jens Friis; Saito-Jensen, Moeko
2013-01-01
of resistance orchestrated by initially disadvantaged groups. Based on the cases we argue that studies of elite capture should be based on in-depth and longitudinal empirical investigations that carefully characterize forms and outcomes of elite capture and consider both the changing dynamics of social settings...
The direct Flow parametric Proof of Gauss' Divergence Theorem revisited
DEFF Research Database (Denmark)
Markvorsen, Steen
The standard proof of the divergence theorem in undergraduate calculus courses covers the theorem for static domains between two graph surfaces. We show that within first year undergraduate curriculum, the flow proof of the dynamic version of the divergence theorem - which is usually considered...... we apply the key instrumental concepts and verify the various steps towards this alternative proof of the divergence theorem....
Energy Technology Data Exchange (ETDEWEB)
Feng, Zhao-Qing [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China)
2017-02-15
Within the framework of the Lanzhou quantum molecular dynamics (LQMD) transport model, pion dynamics in heavy-ion collisions near threshold energies and the emission of preequilibrium particles (nucleons and light complex fragments) have been investigated. A density, momentum and isospin-dependent pion-nucleon potential based on the Δ-hole model is implemented in the transport approach, which slightly leads to the increase of the π{sup -}/π{sup +} ratio, but reduces the total pion yields. It is found that a bump structure of the π{sup -}/π{sup +} ratio in the kinetic energy spectra appears at the pion energy close to the Δ(1232) resonance region. The yield ratios of neutrons to protons from the squeeze-out particles perpendicular to the reaction plane are sensitive to the stiffness of nuclear symmetry energy, in particular at the high-momentum (kinetic energy) tails. (orig.)
Discrete dynamics versus analytic dynamics
DEFF Research Database (Denmark)
Toxværd, Søren
2014-01-01
For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent...... of such an analytic analogy, exists an exact hidden energy invariance E * for VA dynamics. The fact that the discrete VA dynamics has the same invariances as Newtonian dynamics raises the question, which of the formulations that are correct, or alternatively, the most appropriate formulation of classical dynamics....... In this context the relation between the discrete VA dynamics and the (general) discrete dynamics investigated by Lee [Phys. Lett. B122, 217 (1983)] is presented and discussed....
Rangachari, Pavani; Mehta, Renuka; Rethemeyer, R Karl; Ferrang, Carole; Dennis, Clifton; Redd, Vickie
2015-10-01
At the Children's Hospital of Georgia (CHOG), we found that outpatient revisits for pediatric asthma were significantly above national norms. According to the NIH, costly hospital revisits for asthma can be prevented through guidelines-based self-management of asthma, central to which, is the use of a written Asthma-Action Plan (AAP). The asthma services literature has emphasized the role of the healthcare provider in promoting asthma self-management using the AAP, to prevent hospital revisits. On the other hand, the asthma policy literature has emphasized the need for community-based interventions to promote asthma self-management. A gap remains in understanding the extent of leverage that healthcare providers may have in preventing hospital revisits for asthma, through effective communication of AAP in the outpatient setting. Our study sought to address this gap. We conducted a 6-month intervention to implement "patient-and-family-centered communication of the AAP" in CHOG outpatient clinics, based on the "change-management" theoretical framework. Provider communication of AAP was assessed through a survey of "Parent Understanding of the Child's AAP." A quasi-experimental approach was used to measure outpatient revisits for pediatric asthma, pre- and post-intervention. Survey results showed that provider communication of the AAP was unanimously perceived highly positively by parents of pediatric asthma patients, across various metrics of patient-centered care. However, there were no statistically significant differences in outpatient "revisit behavior" for pediatric asthma between pre- and post-intervention periods after controlling for several demographic variables. Additionally, revisits remained significantly above national norms. Results suggest limited potential of "effective provider communication of AAP," in reducing outpatient revisits for pediatric asthma; and indicate need for broader community-based interventions to address patient life variables
Un avenir ouvert pour une sociologie revisitée
Directory of Open Access Journals (Sweden)
Liliane Voyé
2012-05-01
Full Text Available Si l’on peut louer le souci de réflexivité qui anime la sociologie, il convient toutefois de dépasser ce stade du questionnement pour arriver à développer une sociologie moins inquiète d’elle-même. Les raisons de ce malaise sont diverses. Outre l’absence d’accord « sur un socle élémentaire de compétences exigibles » (François Dubet et Alain Caillé, la spécificité de son champ et de ses apports, comparée, par exemple, à l’histoire ou à la géographie, serait aussi une exigence importante, dont la rencontre la rendrait moins fragile. La question des méthodes qu’elle emploie mériterait également l’attention car celles-ci peuvent pécher par leurs faiblesses mais aussi parfois par leurs excès. L’objet même que se donne la sociologie appelle lui aussi une réflexion : la sociologie n’est pas du travail social frotté de science. Pourquoi dès lors privilégier l’étude des « problèmes sociaux » au sens courant du terme et ne pas s’intéresser aussi aux populations sans problème ou tout au moins se considérant comme telles ? Comme en médecine, les personnes saines aident à comprendre les maladies. À une époque où les changements se multiplient dans tous les domaines, la sociologie doit s’atteler à peaufiner sa conceptualisation et à repenser ses paradigmes, pour assumer pleinement son rôle social.An Open Future for a Revisited SociologyIf we can praise the concern for reflexivity that drives sociology, it should however go beyond the stage of questioning in order to develop a sociology that is less worried about itself. The reasons for this discomfort are various. Besides the lack of agreement « on the basis of elementary required skills » (François Dubet et Alain Caillé, the specificity of its field and its contributions, compared for example to history or geography, should also be an important requirement whose meeting would make it less fragile. The question of its methods
Revisiting the advection-dispersion model - Testing an alternative
International Nuclear Information System (INIS)
Neretnieks, I.
2001-01-01
Some of the basic assumptions of the Advection-Dispersion model, AD-model, are revisited. That model assumes a continuous mixing along the flowpath similar to Fickian diffusion. This implies that there is a constant dispersion length irrespective of observation distance. This is contrary to most field observations. The properties of an alternative model based on the assumption that individual water packages can retain their identity over long distances are investigated. The latter model is called the Multi-Channel model, MChM. Inherent in the latter model is that if the waters in the different pathways are collected and mixed, the 'dispersion length' is proportional to observation distance. Using diffusion theory it is investigated over which distances or contact times, adjacent water packages will keep their identity. It is found that for a contact time of 10 hours, two streams, each wider than 6 mm, that flow side by side, will not have lost their identity. For 1000 hours contact time the minimum width is 6 cm. The MChM and AD-models were found to have very similar Residence Time Distributions, RTD, for Peclet numbers larger than 3. A generalised relation between flowrate and residence time is developed, including the so-called cubic law and constant aperture assumptions. Using the generalised relation, surprisingly it is found that for a system that has the same average flow volume and average flowrate the form of the RTD curves are the same irrespective of the form of the relation. Both models are also compared for a system where there is strong interaction of the solute with the rock matrix. In this case it is assumed that the solute can diffuse into and out of the fracture walls and also to sorb on the micro-fractures of the matrix. The so-called Flow Wetted Surface, FWS, between the flowing water in the fracture and the rock is a key entity in such systems. It is found that the AD-model predicts much later arrivals and lower concentrations than does the MCh
The direct Flow parametric Proof of Gauss' Divergence Theorem revisited
Markvorsen, Steen
2006-01-01
The standard proof of the divergence theorem in undergraduate calculus courses covers the theorem for static domains between two graph surfaces. We show that within first year undergraduate curriculum, the flow proof of the dynamic version of the divergence theorem - which is usually considered only much later in more advanced math courses - is comprehensible with only a little extension of the first year curriculum. Moreover, it is more intuitive than the static proof. We support this intuit...
Revisiting the plasma sheath—dust in plasma sheath
Energy Technology Data Exchange (ETDEWEB)
Das, G. C. [Mathematical Science Division, IASST, Guwahati 781014 (India); Deka, R.; Bora, M. P., E-mail: mpbora@gauhati.ac.in [Physics Department, Gauhati University, Guwahati 781014 (India)
2016-04-15
In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of plasma sheath formed around surfaces of various solid bodies in space, though the results obtained in this work can be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. It is important to note that our calculations are valid only when the amount of dust particles is not sufficient so as to affect the plasma dynamics in the dust-acoustic time scale, but enough to affect the plasma sheath. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisson equation.
Federal Laboratory Consortium — The Dynamics Lab replicates vibration environments for every Navy platform. Testing performed includes: Flight Clearance, Component Improvement, Qualification, Life...
Sternberg, Shlomo
2010-01-01
Celebrated mathematician Shlomo Sternberg, a pioneer in the field of dynamical systems, created this modern one-semester introduction to the subject for his classes at Harvard University. Its wide-ranging treatment covers one-dimensional dynamics, differential equations, random walks, iterated function systems, symbolic dynamics, and Markov chains. Supplementary materials offer a variety of online components, including PowerPoint lecture slides for professors and MATLAB exercises.""Even though there are many dynamical systems books on the market, this book is bound to become a classic. The the
Risk prediction of emergency department revisit 30 days post discharge: a prospective study.
Directory of Open Access Journals (Sweden)
Shiying Hao
Full Text Available Among patients who are discharged from the Emergency Department (ED, about 3% return within 30 days. Revisits can be related to the nature of the disease, medical errors, and/or inadequate diagnoses and treatment during their initial ED visit. Identification of high-risk patient population can help device new strategies for improved ED care with reduced ED utilization.A decision tree based model with discriminant Electronic Medical Record (EMR features was developed and validated, estimating patient ED 30 day revisit risk. A retrospective cohort of 293,461 ED encounters from HealthInfoNet (HIN, Maine's Health Information Exchange (HIE, between January 1, 2012 and December 31, 2012, was assembled with the associated patients' demographic information and one-year clinical histories before the discharge date as the inputs. To validate, a prospective cohort of 193,886 encounters between January 1, 2013 and June 30, 2013 was constructed. The c-statistics for the retrospective and prospective predictions were 0.710 and 0.704 respectively. Clinical resource utilization, including ED use, was analyzed as a function of the ED risk score. Cluster analysis of high-risk patients identified discrete sub-populations with distinctive demographic, clinical and resource utilization patterns.Our ED 30-day revisit model was prospectively validated on the Maine State HIN secure statewide data system. Future integration of our ED predictive analytics into the ED care work flow may lead to increased opportunities for targeted care intervention to reduce ED resource burden and overall healthcare expense, and improve outcomes.
Hall, Joanne M; Carlson, Kelly
2016-01-01
In 1994, the concept of marginalization was explored in an article in Advances in Nursing Science. This is a revisitation of the concept incorporating new scholarship. This update is founded on feminism, postcolonialism, critical race theory, and discourse deconstruction, all viewpoints that have been explicated in nursing. The purpose of this analysis is to look at new scholarship and concepts useful to applying marginalization in nursing knowledge development from the standpoint of Bourdieu's macro, meso, and micro levels. New scholarship includes globalization, intersectionality, privilege, microaggressions, and implicit bias. Implications for decreasing health disparities through this new scholarship are discussed.
Revisiting an open access monograph experiment: measuring citations and tweets 5 years later.
Snijder, Ronald
An experiment run in 2009 could not assess whether making monographs available in open access enhanced scholarly impact. This paper revisits the experiment, drawing on additional citation data and tweets. It attempts to answer the following research question: does open access have a positive influence on the number of citations and tweets a monograph receives, taking into account the influence of scholarly field and language? The correlation between monograph citations and tweets is also investigated. The number of citations and tweets measured in 2014 reveal a slight open access advantage, but the influence of language or subject should also be taken into account. However, Twitter usage and citation behaviour hardly overlap.
Governing Education: a revisiting of ‘Political Power beyond the State’ 25 years on
DEFF Research Database (Denmark)
Lim, Miguel Antonio
2016-01-01
that are used in classrooms, management offices, and policy setting agencies. Each of these instruments and calculative devices is pregnant with interest. They bridge the gap between everyday practices and larger governance goals. Yet as the technical sophistication of these instruments increases......This article revisits Political Power Beyond the State: Problematics of Government by sociologist Nikolas Rose and critical accounting scholar Peter Miller. The reach of this influential critique of the nature of power and its exercise ‘beyond the state’ continues to this day, 25 years after...
The importance of jet bending in gamma-ray AGNs—revisited
Energy Technology Data Exchange (ETDEWEB)
Graham, P. J. [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Tingay, S. J. [International Centre for Radio Astronomy Research, Curtin University, Bentley, WA (Australia)
2014-04-01
We investigate the hypothesis that γ-ray-quiet active galactic nuclei (AGNs) have a greater tendency for jet bending than γ-ray-loud AGNs, revisiting the analysis of Tingay et al. We perform a statistical analysis using a large sample of 351 radio-loud AGNs along with γ-ray identifications from the Fermi Large Area Telescope (LAT). Our results show no statistically significant differences in jet-bending properties between γ-ray-loud and γ-ray-quiet populations, indicating that jet bending is not a significant factor for γ-ray detection in AGNs.
Van 't Riet, Jonathan; Crutzen, Rik; De Vries, Hein
2010-09-02
Online health communication has the potential to reach large audiences, with the additional advantages that it can be operational at all times and that the costs per visitor are low. Furthermore, research shows that Internet-delivered interventions can be effective in changing health behaviors. However, exposure to Internet-delivered health-communication programs is generally low. Research investigating predictors of exposure is needed to be able to effectively disseminate online interventions. In the present study, the authors used a longitudinal design with the aim of identifying demographic, psychological, and behavioral predictors of visiting, using, and revisiting an online program promoting physical activity in the general population. A webpage was created providing the public with information about health and healthy behavior. The website included a "physical activity check," which consisted of a physical activity computer-tailoring expert system where visitors could check whether their physical activity levels were in line with recommendations. Visitors who consented to participate in the present study (n = 489) filled in a questionnaire that assessed demographics, mode of recruitment, current physical activity levels, and health motivation. Immediately after, participants received tailored feedback concerning their current physical activity levels and completed a questionnaire assessing affective and cognitive user experience, attitude toward being sufficiently physically active, and intention to be sufficiently physically active. Three months later, participants received an email inviting them once more to check whether their physical activity level had changed. Analyses of visiting showed that more women (67.5%) than men (32.5%) visited the program. With regard to continued use, native Dutch participants (odds ratio [OR] = 2.81, 95% confidence interval [CI] = 1.16-6.81, P = .02) and participants with a strong motivation to be healthy (OR = 1.46, CI = 1
Vestindien Revisited: I kølvandet på kuldampere og cruiseturister
DEFF Research Database (Denmark)
Brichet, Nathalia Sofie; Hastrup, Frida; Ørstedholm, Maroe
2017-01-01
What traces did Denmark officially leave behind when the West Indies were sold to the United States in 1917? And how are the islands still affected today by Denmark’s presence on the islands? The M/S Maritime Museum tries to answer these questions in its special new exhibition, ‘U.S. VIRGIN ISLAN...... special exhibition “U.S. VIRGIN ISLANDS REVISITED – in the wake of colliers and cruise tourists,” to commemorate the centennial anniversary of selling the West Indies to the United States of America....
Directory of Open Access Journals (Sweden)
Szederjesi, T.
2016-04-01
Full Text Available The Allolobophora sturanyi Rosa, 1895 species group is revisited using DNA barcoding and morphology. Barcoding results corroborated the previous treatment of the Allolobophora sturanyi subspecies and furthermore proved that the morphologically similar Allolobophora gestroides Zicsi, 1970 species belong to this species group. Elaboration of new samples from the Apuseni Mts resulted in discovery of a new subspecies A. sturanyi biharica ssp. nov. from the summit of the Bihor range, and a new species A. zicsica from the Vladeasa range similar to A. gestroides described from Northern Hungary.
Silent cries, dancing tears: the metapsychology of art revisited/revised.
Aragno, Anna
2011-04-01
Against the backdrop of a broad survey of the literature on applied psychoanalysis, a number of concepts underpinning the metapsychology of art are revisited and revised: sublimation; interrelationships between primary and secondary processes; symbolization; "fantasy"; and "cathexis." Concepts embedded in dichotomous or drive/energic contexts are examined and reformulated in terms of a continuum of semiotic processes. Freudian dream structure is viewed as a biological/natural template for nonrepressive artistic forms of sublimation. The synthesis presented proposes a model of continuous rather than discontinuous processes, in a nonenergic, biosemiotic metatheoretical framework.