WorldWideScience

Sample records for symmetry restoration effects

  1. Early space symmetry restoration and neutrino experiments

    International Nuclear Information System (INIS)

    Volkov, G.G.; Liparteliani, A.G.; Monich, V.A.

    1986-01-01

    The problem of early space symmetry restoration on the left-right symmetry models and the models with the extended (due to mirror quarks and leptons) fermion sector is being discussed. The experiments in which the derivations from the standard model of electroweak interactions should be studied are presented

  2. Symmetry breaking and restoration in gauge theories

    International Nuclear Information System (INIS)

    Natale, A.A.

    A review is made of the utilization of the Higgs mechanism in spontaneous symmetry breaking. It is shown that such as ideas came from an analogy with the superconductivity phenomenological theory based on a Ginzburg-Landau lagrangean. The symmetry restoration through the temperature influence is studied. (L.C.) [pt

  3. Restored symmetries, quark puzzle, and the Pomeron as a Josephson current. [Clustering effects, quantum supercurrents, cross sections, phase transitions, narrowing gap mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, R V [Instituto de Fisica e Matematica, Lisbon (Portugal)

    1976-07-01

    A special type of symmetry is studied, wherein manifest invariance is restored by direct integration over a set of spontaneously broken ground states. In addition to invariant states and multiplets these symmetry realizations are shown to lead, in general, to clustering effects and quantum supercurrents. A systematic exploration of these symmetry realizations is proposed, mostly in physical situations where it has so far been believed that the only consequences of the symmetry are invariant states and multiplets. An application of these ideas to the quark system yields a possible explanation for the unobservability of free quarks and an interpretation of the Pomeron as a generalized Josephson current. Furthermore, the 'narrowing gap mechanism' suggests an explanation for the behavior of the e/sup +/ e/sup -/ ..-->.. hadrons cross section and a speculation on an approaching phase transition in hadronic production and the observation of free quarks.

  4. Quantum restoration of broken symmetry in onedimensional loop ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 82; Issue 6. Quantum restoration of broken symmetry in ... Keywords. Non-local transformation; broken symmetry; sine-Gordon; sech interaction. ... A specific type of classically broken symmetry is restored in quantum theory. One-dimensional sine-Gordon system and ...

  5. Symmetry non-restoration at high temperature and supersymmetry

    CERN Document Server

    Dvali, Gia; Dvali, Gia

    1996-01-01

    We analyse the high temperature behaviour of softly broken supersymmetric theories taking into account the role played by effective non-renormalizable terms generated by the decoupling of superheavy degrees of freedom or the Planck scale physics. It turns out that discrete or continuous symmetries, spontaneously broken at intermediate scales, may never be restored, at least up to temperatures of the cutoff scale. There are a few interesting differences from the usual non-restoration in non-supersymmetric theories case where one needs at least two Higgs fields and non-restoration takes place for a range of parameters only. We show that with non-renormalizable interactions taken into account the non-restoration can occur for any nonzero range of parameters even for a single Higgs field. We show that such theories in general solve the cosmological domain wall problem, since the thermal production of the dangerous domain walls is enormously suppressed.

  6. Symmetry restoration in the Georgi-Glashow model at finite temperature

    International Nuclear Information System (INIS)

    Guerra Junior, J.M.

    1985-01-01

    Symmetry restoration in the SU(5) model is analysed by means of finite temperature field theory. In our calculations symmetry restoration is due to topological defects which appear thanks to thermodynamical effects. We apply our results in cosmology, in order to explain the primordial inhomogeneity. Our results are compatible with Zeldovich's spectrum. (author) [pt

  7. Mirror Symmetry Breaking and Restoration: The Role of Noise and Chiral Bias

    International Nuclear Information System (INIS)

    Hochberg, David

    2009-01-01

    The nonequilibrium effective potential is computed for the Frank model of spontaneous mirror symmetry breaking (SMSB) in chemistry in which external noise is introduced to account for random environmental effects. When these fluctuations exceed a critical magnitude, mirror symmetry is restored. The competition between ambient noise and the chiral bias due to physical fields and polarized radiation can be explored with this potential.

  8. Chiral symmetry restoration and quasi-elastic electron-nucleus scattering

    International Nuclear Information System (INIS)

    Henley, E.M.; Krein, G.

    1989-01-01

    Chiral symmetry is known to be an important concept in hadronic interactions. It holds in QCD, but is known to be broken at low energies. It is therefore useful to study chiral symmetry and its breaking together with its consequences in nuclear physics. It is the latter phenomena we consider here. It is difficult to study nonperturbative QCD at low energies and models are needed. The Nambu-Jona-Lasinio (NJL) model fits this category; it incorporates chiral symmetry and its breaking, and allows one to study its effects in nucleons and nuclei. In particular, the constituent quark mass varies with density (ρ) and temperature (T). At high ρ and T chiral symmetry is restored. It is the ρ dependence which yields important effects in electron scattering due to partial restoration of chiral symmetry in nuclei. We begin with the NJL model with a small chiral symmetry breaking

  9. Evidence for chiral symmetry restoration in heavy-ion collisions

    Science.gov (United States)

    Moreau, P.; Palmese, A.; Cassing, W.; Seifert, E.; Steinert, T.; Bratkovskaya, E. L.

    2017-11-01

    We study the effect of the chiral symmetry restoration (CSR) on heavy-ion collisions observables in the energy range √{sNN} = 3- 20GeV within the Parton-Hadron-String Dynamics (PHSD) transport approach. The PHSD includes the deconfinement phase transition as well as essential aspects of CSR in the dense and hot hadronic medium, which are incorporated in the Schwinger mechanism for particle production. Our systematic studies show that chiral symmetry restoration plays a crucial role in the description of heavy-ion collisions at √{sNN} = 3- 20GeV, realizing an increase of the hadronic particle production in the strangeness sector with respect to the non-strange one. Our results provide a microscopic explanation for the horn structure in the excitation function of the K+ /π+ ratio: the CSR in the hadronic phase produces the steep increase of this particle ratio up to √{sNN} ≈ 7GeV, while the drop at higher energies is associated to the appearance of a deconfined partonic medium. Furthermore, the appearance/disappearance of the horn structure is investigated as a function of the system size. We additionally present an analysis of strangeness production in the (T ,μB)-plane (as extracted from the PHSD for central Au+Au collisions) and discuss the perspectives to identify a possible critical point in the phase diagram.

  10. Chiral-symmetry restoration in baryon-rich environments

    International Nuclear Information System (INIS)

    Kogut, J.; Matsuoka, H.; Stone, M.; Wyld, H.W.; Shenker, S.; Shigemitsu, J.; Sinclair, D.K.

    1983-04-01

    Chiral symmetry restoration in an environment rich in baryons is studied by computer simulation methods in SU(2) and SU(3) gauge theories in the quenched approximation. The basic theory of symmetry restoration as a function of chemical potential is illustrated and the implementation of the ideas on a lattice is made explicit. A simple mean field model is presented to guide one's expectations. The second order conjugate-gradient iterative method and the pseudo-fermion Monte Carlo procedure are convergent methods of calculating the fermion propagator in an environment rich in baryons. Computer simulations of SU(3) gauge theory show an abrupt chiral symmetry restoring transition and the critical chemical potential and induced baryon density are estimated crudely. A smoother transition is observed for the color group SU(2)

  11. Low-energy restoration of parity and maximal symmetry

    International Nuclear Information System (INIS)

    Raychaudhuri, A.; Sarkar, U.

    1982-01-01

    The maximal symmetry of fermions of one generation, SU(16), which includes the left-right-symmetric Pati-Salam group, SU(4)/sub c/ x SU(2) /sub L/ x SU(2)/sub R/, as a subgroup, allows the possibility of a low-energy (M/sub R/approx.100 GeV) breaking of the left-right symmetry. It is known that such a low-energy restoration of parity can be consistent with weak-interaction phenomenology. We examine different chains of descent of SU(16) that admit a low value of M/sub R/ and determine the other intermediate symmetry-breaking mass scales associated with each of these chains. These additional mass scales provide an alternative to the ''great desert'' expected in some grand unifying models. The contributions of the Higgs fields in the renormalization-group equations are retained and are found to be important

  12. Consequences of the partial restoration of chiral symmetry in an AdS/QCD model

    International Nuclear Information System (INIS)

    Kim, Youngman; Lee, Hyun Kyu

    2008-01-01

    Chiral symmetry is an essential concept in understanding QCD at low energy. We treat the chiral condensate, which measures the spontaneous breaking of chiral symmetry, as a free parameter to investigate the effect of partially restored chiral symmetry on the physical quantities in the framework of an AdS/QCD model. We observe an interesting scaling behavior among the nucleon mass, pion decay constant, and chiral condensate. We propose a phenomenological way to introduce the temperature dependence of a physical quantity in the AdS/QCD model with the thermal AdS metric.

  13. Chiral symmetry restoration and pion properties in a q-deformed NJL model

    International Nuclear Information System (INIS)

    Timoteo, V.S.; Lima, C.L.

    2006-01-01

    We review the implementation of a q-deformed fermionic algebra in the Nambu-Jona-Lasinio model (NJL). The gap equations obtained from a deformed condensate as well as from the deformation of the NJL Hamiltonian are discussed. The effect of both temperature and deformation in the chiral symmetry restoration process as well as in the pion properties is studied. (author)

  14. Symmetry broken and restored coupled-cluster theory: I. Rotational symmetry and angular momentum

    International Nuclear Information System (INIS)

    Duguet, T

    2015-01-01

    We extend coupled-cluster (CC) theory performed on top of a Slater determinant breaking rotational symmetry to allow for the exact restoration of the angular momentum at any truncation order. The main objective relates to the description of near-degenerate finite quantum systems with an open-shell character. As such, the newly developed many-body formalism offers a wealth of potential applications and further extensions dedicated to the ab initio description of, e.g., doubly open-shell atomic nuclei and molecule dissociation. The formalism, which encompasses both single-reference CC theory and projected Hartree–Fock theory as particular cases, permits the computation of usual sets of connected diagrams while consistently incorporating static correlations through the highly non-perturbative restoration of rotational symmetry. Interestingly, the yrast spectroscopy of the system, i.e. the lowest energy associated with each angular momentum, is accessed within a single calculation. A key difficulty presently overcome relates to the necessity to handle generalized energy and norm kernels for which naturally terminating CC expansions could be eventually obtained. The present work focuses on SU(2) but can be extended to any (locally) compact Lie group and to discrete groups, such as most point groups. In particular, the formalism will be soon generalized to U(1) symmetry associated with particle number conservation. This is relevant to Bogoliubov CC theory that was recently applied to singly open-shell nuclei. (paper)

  15. Dynamical symmetry restoration for a higher-derivative four-fermion model in an external electromagnetic field

    International Nuclear Information System (INIS)

    Elizalde, E.; Gavrilov, S.P.; Shil'nov, Yu.I.

    2000-01-01

    A four-fermion model with additional higher-derivative terms is investigated in an external electromagnetic field. The effective potential in the leading order of large-N expansion is calculated in external constant magnetic and electric fields. It is shown that, in contrast to the former results concerning the universal character of 'magnetic catalysis' in dynamical symmetry breaking, in the present higher-derivative model the magnetic field restores chiral symmetry broken initially on the tree level. Numerical results describing a second-order phase transition that accompanies the symmetry restoration at the quantum level are presented. (author)

  16. On the restoration of symmetry in paired Fermion systems

    International Nuclear Information System (INIS)

    Flocard, H.

    1997-01-01

    We consider the problem of symmetry restoration as treated by the method of variation after projection (VAP) on good quantum numbers. We show that for compact groups, the convergence of the connected-linked expansion of the VAP kernels over the physically relevant interval of integration of the pairing gauge angle is not guaranteed. We propose instead a method which generates approximations of increasing precision which are periodic with respect to the gauge angle while differing from truncations of the Fourier expansion of the VAP kernels. For the projection on good particle number in paired fermion systems, this new approach is shown to be equivalent to an expansion in powers of the pairing tensor. For the lowest order approximation, an analytical integration over the gauge angle is performed explicitly. It provides the algebraic forms of the single particle Hamiltonian and of the pairing field entering generalized Hartree endash Fock endash Bogoljubov equations. Contrary to most approximations, the validity of the expressions for the energy and mean values of operators thus obtained is not a priori restricted where the fluctuation of the operator associated with the broken symmetry is large. We also derive the first-order correction to the pairing-order parameter. We test the quality of the proposed method on a non-trivial soluble model. copyright 1997 Academic Press, Inc

  17. Dynamical Symmetry Breaking of Maximally Generalized Yang-Mills Model and Its Restoration at Finite Temperatures

    International Nuclear Information System (INIS)

    Wang Dianfu

    2008-01-01

    In terms of the Nambu-Jona-Lasinio mechanism, dynamical breaking of gauge symmetry for the maximally generalized Yang-Mills model is investigated. The gauge symmetry behavior at finite temperature is also investigated and it is shown that the gauge symmetry broken dynamically at zero temperature can be restored at finite temperatures

  18. Finite-temperature symmetry restoration in the four-dimensional Φ4 model with four components

    International Nuclear Information System (INIS)

    Jansen, K.

    1990-01-01

    The finite-temperature symmetry restoration in the four-dimensional φ 4 theory with four components and with an infinite self-coupling is studied by means of Monte Carlo simulations on lattices with time extensions L t =4,5,6 and space extensions 12 3 -28 3 . The numerical calculations are done by means of the Wolff cluster algorithm which is very efficient for simulations near a phase transition. The numerical results are in good agreement with an improved one-loop expansion and with the 1/N-expansion, indicating that in the electroweak theory the symmetry restoration temperature T sr is about 350 GeV. (orig.)

  19. Symmetry and symmetry restoration of lattice chiral fermions in the overlap formalism

    International Nuclear Information System (INIS)

    Kikukawa, Y.

    1999-01-01

    Three aspects of the symmetry structure of lattice chiral fermions in the overlap formalism are discussed. By the weak coupling expansion of the overlap Dirac operator, the axial anomaly associated to the chiral transformation proposed by Luescher is evaluated and is shown to have the correct form of the topological charge density for perturbative backgrounds. Next we discuss the exponential suppression of the self-energy correction of the lightest mode in the domain-wall fermion/truncated overlap. Finally, we consider a supersymmetric extension of the overlap formula in the case of the chiral multiplet and examine the symmetry structure of the action

  20. Shells, orbit bifurcations, and symmetry restorations in Fermi systems

    Energy Technology Data Exchange (ETDEWEB)

    Magner, A. G., E-mail: magner@kinr.kiev.ua; Koliesnik, M. V. [NASU, Institute for Nuclear Research (Ukraine); Arita, K. [Nagoya Institute of Technology, Department of Physics (Japan)

    2016-11-15

    The periodic-orbit theory based on the improved stationary-phase method within the phase-space path integral approach is presented for the semiclassical description of the nuclear shell structure, concerning themain topics of the fruitful activity ofV.G. Soloviev. We apply this theory to study bifurcations and symmetry breaking phenomena in a radial power-law potential which is close to the realistic Woods–Saxon one up to about the Fermi energy. Using the realistic parametrization of nuclear shapes we explain the origin of the double-humped fission barrier and the asymmetry in the fission isomer shapes by the bifurcations of periodic orbits. The semiclassical origin of the oblate–prolate shape asymmetry and tetrahedral shapes is also suggested within the improved periodic-orbit approach. The enhancement of shell structures at some surface diffuseness and deformation parameters of such shapes are explained by existence of the simple local bifurcations and new non-local bridge-orbit bifurcations in integrable and partially integrable Fermi-systems. We obtained good agreement between the semiclassical and quantum shell-structure components of the level density and energy for several surface diffuseness and deformation parameters of the potentials, including their symmetry breaking and bifurcation values.

  1. Consciousness induced restoration of time symmetry (CIRTS): a psychophysical theoretical perspective

    NARCIS (Netherlands)

    Bierman, D.J.

    2010-01-01

    A theoretical framework is proposed that starts from the assumption that information processing by a brain, while it is sustaining consciousness, is restoring the break in time symmetry in physics. No specifics are given with regard to which physical formalism, either quantum or classical, is the

  2. Evaluating chiral symmetry restoration through the use of sum rules

    Directory of Open Access Journals (Sweden)

    Rapp Ralf

    2012-11-01

    Full Text Available We pursue the idea of assessing chiral restoration via in-medium modifications of hadronic spectral functions of chiral partners. The usefulness of sum rules in this endeavor is illustrated, focusing on the vector/axial-vector channel. We first present an update on obtaining quantitative results for pertinent vacuum spectral functions. These serve as a basis upon which the in-medium spectral functions can be constructed. A novel feature of our analysis of the vacuum spectral functions is the need to include excited resonances, dictated by satisfying the Weinberg-type sum rules. This includes excited states in both the vector and axial-vector channels.We also analyze the QCD sum rule for the finite temperature vector spectral function, based on a ρ spectral function tested in dilepton data which develops a shoulder at low energies.We find that the ρ′ peak flattens off which may be a sign of chiral restoration, though a study of the finite temperature axial-vector spectral function remains to be carried out.

  3. Signatures of chiral symmetry restoration and its survival throughout the hadronic phase interactions

    Directory of Open Access Journals (Sweden)

    Bratkovskaya E.L.

    2018-01-01

    Full Text Available The effect of the chiral symmetry restoration (CSR on observables from heavy-ion collisions is studied in the energy range sNN=3–20 GeV within the Parton-Hadron-String Dynamics (PHSD transport approach. The PHSD includes the deconfinement phase transition as well as essential aspects of CSR in the dense and hot hadronic medium, which are incorporated in the Schwinger mechanism for the hadronic particle production. We adopt different parametrizations of the nuclear equation of state from the non-linear σ - ω model, which enter in the computation of the quark scalar density for the CSR mechanism, in order to estimate the uncertainty in our calculations. For the pion-nucleon ∑-term we adopt ∑π ≈ 45 MeV which corresponds to a ’world average’. Our systematic studies show that chiral symmetry restoration plays a crucial role in the description of heavy-ion collisions at sNN=3–20 GeV, realizing an increase of the hadronic particle production in the strangeness sector with respect to the non-strange one. We identify particle abundances and rapidity spectra to be suitable probes in order to extract information about CSR, while transverse mass spectra are less sensitive ones. Our results provide a microscopic explanation for the "horn" structure in the excitation function of the K+/π+ ratio: the CSR in the hadronic phase produces the steep increase of this particle ratio up to sNN ≈ 7 GeV, while the drop at higher energies is associated to the appearance of a deconfined partonic medium.

  4. Chiral symmetry restoration versus deconfinement in heavy-ion collisions at high baryon density

    Science.gov (United States)

    Bratkovskaya, E. L.; Palmese, A.; Cassing, W.; Seifert, E.; Steinert, T.; Moreau, P.

    2017-07-01

    The effect of the chiral symmetry restoration (CSR) on observables from heavy-ion collisions is studied in the energy range \\sqrt{{s}NN}=3-20 {GeV} within the Parton-Hadron-String Dynamics (PHSD) transport approach. The PHSD includes the deconfinement phase transition as well as essential aspects of CSR in the dense and hot hadronic medium, which are incorporated in the Schwinger mechanism for the hadronic particle production. We adopt different parametrizations of the nuclear equation of state from the non-linear σ - ω model, which enter in the computation of the quark scalar density for the CSR mechanism, in order to estimate the uncertainty in our calculations. For the pion-nucleon Σ-term we adopt Σ π ≈ 45 MeV which corresponds to some ‘world average’. Our systematic studies show that chiral symmetry restoration plays a crucial role in the description of heavy-ion collisions at \\sqrt{{s}NN}=3-20 {GeV}, realizing an increase of the hadronic particle production in the strangeness sector with respect to the non-strange one. We identify particle abundances and rapidity spectra to be suitable probes in order to extract information about CSR, while transverse mass spectra are less sensitive. Our results provide a microscopic explanation for the “horn” structure in the excitation function of the K +/π + ratio: the CSR in the hadronic phase produces the steep increase of this particle ratio up to \\sqrt{{s}NN}≈ 7 {GeV}, while the drop at higher energies is associated to the appearance of a deconfined partonic medium.

  5. Signatures of chiral symmetry restoration and its survival throughout the hadronic phase interactions

    Science.gov (United States)

    Bratkovskaya, E. L.; Moreau, P.; Palmese, A.; Cassing, W.; Seifert, E.; Steinert, T.

    2018-02-01

    The effect of the chiral symmetry restoration (CSR) on observables from heavy-ion collisions is studied in the energy range =3-20 GeV within the Parton-Hadron-String Dynamics (PHSD) transport approach. The PHSD includes the deconfinement phase transition as well as essential aspects of CSR in the dense and hot hadronic medium, which are incorporated in the Schwinger mechanism for the hadronic particle production. We adopt different parametrizations of the nuclear equation of state from the non-linear σ - ω model, which enter in the computation of the quark scalar density for the CSR mechanism, in order to estimate the uncertainty in our calculations. For the pion-nucleon ∑-term we adopt ∑π ≈ 45 MeV which corresponds to a 'world average'. Our systematic studies show that chiral symmetry restoration plays a crucial role in the description of heavy-ion collisions at =3-20 GeV, realizing an increase of the hadronic particle production in the strangeness sector with respect to the non-strange one. We identify particle abundances and rapidity spectra to be suitable probes in order to extract information about CSR, while transverse mass spectra are less sensitive ones. Our results provide a microscopic explanation for the "horn" structure in the excitation function of the K+/π+ ratio: the CSR in the hadronic phase produces the steep increase of this particle ratio up to ≈ 7 GeV, while the drop at higher energies is associated to the appearance of a deconfined partonic medium.

  6. Effective lagrangian description on discrete gauge symmetries

    International Nuclear Information System (INIS)

    Banks, T.

    1989-01-01

    We exhibit a simple low-energy lagrangian which describes a system with a discrete remnant of a spontaneously broken continuous gauge symmetry. The lagrangian gives a simple description of the effects ascribed to such systems by Krauss and Wilczek: black holes carry discrete hair and interact with cosmic strings, and wormholes cannot lead to violation of discrete gauge symmetries. (orig.)

  7. Restoration of the local gauge symmetry and color confinement in non-Abelian gauge theories

    International Nuclear Information System (INIS)

    Hata, Hiroyuki

    1982-01-01

    Restoration of the local gauge symmetry and its connection to color confinement is investigated in non-Abelian gauge theories with covariant gauge fixing. We consider the Noether current J sub(μ,#betta#)sup(a) of the local gauge transformation with transformation functions #betta#sup(b)(x) linear in x sub(μ); #betta#sup(b)(x) = delta sup(ab)x sub(#betta#). This current is conserved only in the physical subspace of the state vector space and in perturbation theory contains a massless pole communicating to the gauge field. We define the local gauge symmetry restoration as the disappearance of this massless ''Goldstone'' pole from J sub(μ,#betta#)sup(a). The restoration condition is obtained and it coincides exactly with the color confinement criterion proposed earlier by Kugo and Ojima. Quarks and other colored particles are shown to be confined in the local gauge symmetry restored phase by using the Ward identities of J sub(μ,#betta#)sup(a). (author)

  8. Infinite symmetry in the quantum Hall effect

    Directory of Open Access Journals (Sweden)

    Lütken C.A.

    2014-04-01

    Full Text Available The new states of matter and concomitant quantum critical phenomena revealed by the quantum Hall effect appear to be accompanied by an emergent modular symmetry. The extreme rigidity of this infinite symmetry makes it easy to falsify, but two decades of experiments have failed to do so, and the location of quantum critical points predicted by the symmetry is in increasingly accurate agreement with scaling experiments. The symmetry severely constrains the structure of the effective quantum field theory that encodes the low energy limit of quantum electrodynamics of 1010 charges in two dirty dimensions. If this is a non-linear σ-model the target space is a torus, rather than the more familiar sphere. One of the simplest toroidal models gives a critical (correlation length exponent that agrees with the value obtained from numerical simulations of the quantum Hall effect.

  9. Topology in the SU(Nf) chiral symmetry restored phase of unquenched QCD and axion cosmology

    Science.gov (United States)

    Azcoiti, Vicente

    2018-03-01

    The axion is one of the more interesting candidates to make the dark matter of the universe, and the axion potential plays a fundamental role in the determination of the dynamics of the axion field. Moreover, the way in which the U(1)A anomaly manifests itself in the chiral symmetry restored phase of QCD at high temperature could be tested when probing the QCD phase transition in relativistic heavy ion collisions. With these motivations, we investigate the physical consequences of the survival of the effects of the U(1)A anomaly in the chiral symmetric phase of QCD, and show that the free energy density is a singular function of the quark mass m, in the chiral limit, and that the σ and π susceptibilities diverge in this limit at any T ≥ Tc. We also show that the difference between the π and t;δ susceptibilities diverges in the chiral limit at any T ≥ Tc, a result that can be contrasted with the existing lattice calculations; and discuss on the generalization of these results to the Nf ≥ 3 model.

  10. Restoration of supersymmetric Slavnov-Taylor and Ward identities in the presence of soft and spontaneous symmetry breaking

    International Nuclear Information System (INIS)

    Fischer, I.; Hollik, W.; Roth, M.; Stoeckinger, D.

    2004-01-01

    Supersymmetric Slavnov-Taylor and Ward identities are investigated in the presence of soft and spontaneous symmetry breaking. We consider an Abelian model where soft supersymmetry breaking yields a mass splitting between electron and selectron and triggers spontaneous symmetry breaking, and we derive the corresponding identities that relate the electron and selectron masses to the Yukawa coupling. We demonstrate that the identities are valid in dimensional reduction and invalid in dimensional regularization and compute the necessary symmetry-restoring counterterms

  11. Restoration of supersymmetric Slavnov-Taylor and Ward identities in presence of soft and spontaneous symmetry breaking

    International Nuclear Information System (INIS)

    Fischer, I.; Hollik, W.; Roth, M.; Stoeckinger, D.

    2003-12-01

    Supersymmetric Slavnov-Taylor and Ward identities are investigated in presence of soft and spontaneous symmetry breaking. We consider an abelian model where soft supersymmetry breaking yields a mass splitting between electron and selectron and triggers spontaneous symmetry breaking, and we derive corresponding identities that relate the electron and selectron masses with the Yukawa coupling. We demonstrate that the identities are valid in dimensional reduction and invalid in dimensional regularization and compute the necessary symmetry-restoring counterterms. (orig.)

  12. En route to Background Independence: Broken split-symmetry, and how to restore it with bi-metric average actions

    International Nuclear Information System (INIS)

    Becker, D.; Reuter, M.

    2014-01-01

    The most momentous requirement a quantum theory of gravity must satisfy is Background Independence, necessitating in particular an ab initio derivation of the arena all non-gravitational physics takes place in, namely spacetime. Using the background field technique, this requirement translates into the condition of an unbroken split-symmetry connecting the (quantized) metric fluctuations to the (classical) background metric. If the regularization scheme used violates split-symmetry during the quantization process it is mandatory to restore it in the end at the level of observable physics. In this paper we present a detailed investigation of split-symmetry breaking and restoration within the Effective Average Action (EAA) approach to Quantum Einstein Gravity (QEG) with a special emphasis on the Asymptotic Safety conjecture. In particular we demonstrate for the first time in a non-trivial setting that the two key requirements of Background Independence and Asymptotic Safety can be satisfied simultaneously. Carefully disentangling fluctuation and background fields, we employ a ‘bi-metric’ ansatz for the EAA and project the flow generated by its functional renormalization group equation on a truncated theory space spanned by two separate Einstein–Hilbert actions for the dynamical and the background metric, respectively. A new powerful method is used to derive the corresponding renormalization group (RG) equations for the Newton- and cosmological constant, both in the dynamical and the background sector. We classify and analyze their solutions in detail, determine their fixed point structure, and identify an attractor mechanism which turns out instrumental in the split-symmetry restoration. We show that there exists a subset of RG trajectories which are both asymptotically safe and split-symmetry restoring: In the ultraviolet they emanate from a non-Gaussian fixed point, and in the infrared they loose all symmetry violating contributions inflicted on them by the

  13. Chiral-symmetry restoration at finite densities in Coulomb-gauge QCD

    International Nuclear Information System (INIS)

    Kocic, A.

    1986-01-01

    Using the Schwinger-Dyson equation in the Hartree-Fock approximation, we show that, within a potential model motivated by the QCD Hamiltonian in the Coulomb gauge, chiral symmetry is restored at finite densities. Two cases are studied: a delta-function potential and a linear confining potential. For the former case the phase diagram is obtained analytically, whereas for the latter case numerical techniques are used. The values of physical quantities calculated for the linear confining model are consistently smaller than the experimental ones indicating that a potential with additional short-range attraction is needed to describe the quark interaction in the high-density regime

  14. Particle-hole symmetry for composite fermions: An emergent symmetry in the fractional quantum Hall effect

    DEFF Research Database (Denmark)

    Coimbatore Balram, Ajit; Jain, Jainendra

    2017-01-01

    The particle-hole (PH) symmetry of {\\em electrons} is an exact symmetry of the electronic Hamiltonian confined to a specific Landau level, and its interplay with the formation of composite fermions has attracted much attention of late. This article investigates an emergent symmetry...... in the fractional quantum Hall effect, namely the PH symmetry of {\\em composite fermions}, which relates states at composite fermion filling factors $\

  15. Statistical symmetry restoration in fully developed turbulence: Renormalization group analysis of two models

    Science.gov (United States)

    Antonov, N. V.; Gulitskiy, N. M.; Kostenko, M. M.; Malyshev, A. V.

    2018-03-01

    In this paper we consider the model of incompressible fluid described by the stochastic Navier-Stokes equation with finite correlation time of a random force. Inertial-range asymptotic behavior of fully developed turbulence is studied by means of the field theoretic renormalization group within the one-loop approximation. It is corroborated that regardless of the values of model parameters and initial data the inertial-range behavior of the model is described by the limiting case of vanishing correlation time. This indicates that the Galilean symmetry of the model violated by the "colored" random force is restored in the inertial range. This regime corresponds to the only nontrivial fixed point of the renormalization group equation. The stability of this point depends on the relation between the exponents in the energy spectrum E ∝k1 -y and the dispersion law ω ∝k2 -η . The second analyzed problem is the passive advection of a scalar field by this velocity ensemble. Correlation functions of the scalar field exhibit anomalous scaling behavior in the inertial-convective range. We demonstrate that in accordance with Kolmogorov's hypothesis of the local symmetry restoration the main contribution to the operator product expansion is given by the isotropic operator, while anisotropic terms should be considered only as corrections.

  16. Can a pseudo-Nambu-Goldstone Higgs lead to symmetry non-restoration?

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, Can; Swaminathan, Sivaramakrishnan [Weinberg Theory Group, Department of Physics and Texas Cosmology Center,The University of Texas at Austin,2515 Speedway Stop C1608, Austin, TX, 78712-1197 (United States)

    2016-01-04

    The calculation of finite temperature contributions to the scalar potential in a quantum field theory is similar to the calculation of loop corrections at zero temperature. In natural extensions of the Standard Model where loop corrections to the Higgs potential cancel between Standard Model degrees of freedom and their symmetry partners, it is interesting to contemplate whether finite temperature corrections also cancel, raising the question of whether a broken phase of electroweak symmetry may persist at high temperature. It is well known that this does not happen in supersymmetric theories because the thermal contributions of bosons and fermions do not cancel each other. However, for theories with same spin partners, the answer is less obvious. Using the Twin Higgs model as a benchmark, we show that although thermal corrections do cancel at the level of quadratic divergences, subleading corrections still drive the system to a restored phase. We further argue that our conclusions generalize to other well-known extensions of the Standard Model where the Higgs is rendered natural by being the pseudo-Nambu-Goldstone mode of an approximate global symmetry.

  17. Symmetry behavior of the effective gauge theory

    International Nuclear Information System (INIS)

    Midorikawa, S.

    1981-01-01

    The restoration of spontaneously broken CP invariance is investigated by using the effective QED lagrangian obtained from the standard SU(2) x U(1) gauge theory with two Higgs doublets. It is shown that the large electromagnetic field may restore CP invariance by changing the relative phase angle of Higgs vacuum expectation values even before one of the vacuum expectation values of the two Higgs doublets disappears. Further large magnetic field may lead to the fine structure constant with discontinuous behavior. (orig.)

  18. Chiral Lagrangian with broken scale: Testing the restoration of symmetries in astrophysics and in the laboratory

    International Nuclear Information System (INIS)

    Bonanno, Luca; Drago, Alessandro

    2009-01-01

    We study matter at high density and temperature using a chiral Lagrangian in which the breaking of scale invariance is regulated by the value of a scalar field, called dilaton [E. K. Heide, S. Rudaz, and P. J. Ellis, Nucl. Phys. A571, 713 (1994); G. W. Carter, P. J. Ellis, and S. Rudaz, Nucl. Phys. A603, 367 (1996); G. W. Carter, P. J. Ellis, and S. Rudaz, Nucl. Phys. A618, 317 (1997); G. W. Carter and P. J. Ellis, Nucl. Phys. A628, 325 (1998)]. We provide a phase diagram describing the restoration of chiral and scale symmetries. We show that chiral symmetry is restored at large temperatures, but at low temperatures it remains broken at all densities. We also show that scale invariance is more easily restored at low rather than large baryon densities. The masses of vector-mesons scale with the value of the dilaton and their values initially slightly decrease with the density but then they increase again for densities larger than ∼3ρ 0 . The pion mass increases continuously with the density and at ρ 0 and T=0 its value is ∼30 MeV larger than in the vacuum. We show that the model is compatible with the bounds stemming from astrophysics, as, e.g., the one associated with the maximum mass of a neutron star. The most striking feature of the model is a very significant softening at large densities, which manifests also as a strong reduction of the adiabatic index. Although the softening has probably no consequence for supernova explosion via the direct mechanism, it could modify the signal in gravitational waves associated with the merging of two neutron stars.

  19. Effective potential and chiral symmetry breaking

    International Nuclear Information System (INIS)

    Hochberg, David

    2010-01-01

    The nonequilibrium effective potential is calculated for the Frank model of spontaneous mirror-symmetry breaking in chemistry in which external noise is introduced to account for random environmental effects. The well-mixed limit, corresponding to negligible diffusion, and the case of diffusion in two space dimensions are studied in detail. White noise has a disordering effect in the former case, whereas in the latter case a phase transition occurs for external noise exceeding a critical intensity which racemizes the system.

  20. Interacting fermions in rotation: chiral symmetry restoration, moment of inertia and thermodynamics

    International Nuclear Information System (INIS)

    Chernodub, M.N.; Gongyo, Shinya

    2017-01-01

    We study rotating fermionic matter at finite temperature in the framework of the Nambu-Jona-Lasinio model. In order to respect causality the rigidly rotating system must be bound by a cylindrical boundary with appropriate boundary conditions that confine the fermions inside the cylinder. We show the finite geometry with the MIT boundary conditions affects strongly the phase structure of the model leading to three distinct regions characterized by explicitly broken (gapped), partially restored (nearly gapless) and spontaneously broken (gapped) phases at, respectively, small, moderate and large radius of the cylinder. The presence of the boundary leads to specific steplike irregularities of the chiral condensate as functions of coupling constant, temperature and angular frequency. These steplike features have the same nature as the Shubnikov-de Haas oscillations with the crucial difference that they occur in the absence of both external magnetic field and Fermi surface. At finite temperature the rotation leads to restoration of spontaneously broken chiral symmetry while the vacuum at zero temperature is insensitive to rotation (“cold vacuum cannot rotate”). As the temperature increases the critical angular frequency decreases and the transition becomes softer. A phase diagram in angular frequency-temperature plane is presented. We also show that at fixed temperature the fermion matter in the chirally restored (gapless) phase has a higher moment of inertia compared to the one in the chirally broken (gapped) phase.

  1. Interacting fermions in rotation: chiral symmetry restoration, moment of inertia and thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Chernodub, M.N. [CNRS, Laboratoire de Mathématiques et Physique Théorique, Université de Tours,Tours (France); Laboratory of Physics of Living Matter, Far Eastern Federal University,Vladivostok (Russian Federation); Gongyo, Shinya [CNRS, Laboratoire de Mathématiques et Physique Théorique, Université de Tours,Tours (France); Theoretical Research Division, Nishina Center, RIKEN,Saitama (Japan)

    2017-01-30

    We study rotating fermionic matter at finite temperature in the framework of the Nambu-Jona-Lasinio model. In order to respect causality the rigidly rotating system must be bound by a cylindrical boundary with appropriate boundary conditions that confine the fermions inside the cylinder. We show the finite geometry with the MIT boundary conditions affects strongly the phase structure of the model leading to three distinct regions characterized by explicitly broken (gapped), partially restored (nearly gapless) and spontaneously broken (gapped) phases at, respectively, small, moderate and large radius of the cylinder. The presence of the boundary leads to specific steplike irregularities of the chiral condensate as functions of coupling constant, temperature and angular frequency. These steplike features have the same nature as the Shubnikov-de Haas oscillations with the crucial difference that they occur in the absence of both external magnetic field and Fermi surface. At finite temperature the rotation leads to restoration of spontaneously broken chiral symmetry while the vacuum at zero temperature is insensitive to rotation (“cold vacuum cannot rotate”). As the temperature increases the critical angular frequency decreases and the transition becomes softer. A phase diagram in angular frequency-temperature plane is presented. We also show that at fixed temperature the fermion matter in the chirally restored (gapless) phase has a higher moment of inertia compared to the one in the chirally broken (gapped) phase.

  2. Tunneling magnetoresistance from a symmetry filtering effect

    International Nuclear Information System (INIS)

    Butler, William H

    2008-01-01

    This paper provides a brief overview of the young, but rapidly growing field of spintronics. Its primary objective is to explain how as electrons tunnel through simple insulators such as MgO, wavefunctions of certain symmetries are preferentially transmitted. This symmetry filtering property can be converted into a spin-filtering property if the insulator is joined epitaxially to a ferromagnetic electrode with the same two-dimensional symmetry parallel to the interface. A second requirement of the ferromagnetic electrodes is that a wavefunction with the preferred symmetry exists in one of the two spin channels but not in the other. These requirements are satisfied for electrons traveling perpendicular to the interface for Fe-MgO-Fe tunnel barriers. This leads to a large change in the resistance when the magnetic moment of one of the electrodes is rotated relative to those of the other electrode. This large tunneling magnetoresistance effect is being used as the read sensor in hard drives and may form the basis for a new type of magnetic memory. (topical review)

  3. Effective theories with broken flavour symmetry

    International Nuclear Information System (INIS)

    Miller, R.D.C.; McKellar, B.H.J.

    1981-07-01

    The work of Ovrut and Schnitzer on effective theories derived from a non Abelian Gauge Theory is generalised to include the physically interesting case of broken flavour symmetry. The calculations are performed at the 1-loop level. It is shown that at an intermediate stage in the calculations two distinct renormalised gauge coupling constants appear, one describing gauge field coupling to heavy particles and the other describing coupling to light particles. Appropriately modified Slavnov-Taylor identities are shown to hold. A simple alternative to the Ovrut-Schnitzer rules for calculating with effective theories is also considered

  4. Breaking of electroweak symmetry: origin and effects

    International Nuclear Information System (INIS)

    Delaunay, C.

    2008-10-01

    The Higgs boson appears as the corner stone of high energy physics, it might be the cause of the excess of matter that led to the formation of the structures of the universe and it seems that it drives the breaking of the electroweak symmetry. Moreover, when the stability at low energies of the Higgs boson is assured by an extra space dimension, it appears that this extra dimension can explain most issues in the flavor physics that are not understood by the standard model. The first chapter presents the main tools of effective field theories, the role of experimental data in the construction of theories valid beyond the standard model is discussed. The second chapter focuses on the electroweak baryogenesis that allows the testing of new physics via the electroweak phase transition. We detail the calculation of a Higgs potential at finite temperature. We follow the dynamics of the phase transition including nucleation an supercooling. Finally we investigate the prospects of gravity wave detection to see the effects of a strong electroweak phase transition. The 2 last chapters are dedicated to the physics of extra-dimension. The properties of the dynamics of scalar, vector fields with a 1/2 spin plunged in a 5 d. Anti de Sitter geometry are reviewed. We present a model of lepton masses and mixings based on the A 4 non-Abelian discrete symmetry. It is shown that this model does not contradict the tests of electroweak precision. (A.C.)

  5. Chiral Symmetry Restoration, Naturalness and the Absence of Fine-Tuning I: Global Theories

    CERN Document Server

    Lynn, Bryan W.

    2013-01-01

    The Standard Model (SM), and the scalar sector of its zero-gauge-coupling limit -- the chiral-symmetric limit of the Gell Mann-Levy Model (GML) -- have been shown not to suffer from a Higgs Fine-Tuning (FT) problem. All ultraviolet quadratic divergences (UVQD) are absorbed into the mass-squared of pseudo Nambu-Goldstone (pNGB) bosons, in GML. Since chiral SU(2)_{L-R} symmetry is restored as the pNGB mass-squared or as the Higgs vacuum expectation value (VEV) are taken to 0, small values of these quantities and of the Higgs mass are natural, and therefore not Fine-Tuned. In this letter, we extend our results on the absence of FT to a wide class of high-mass-scale (M_{Heavy}>>m_{Higgs}) extensions to a simplified SO(2) version of GML. We explicitly demonstrate naturalness and no-FT for two examples of heavy physics, both SO(2) singlets: a heavy (M_S >> m_{Higgs}) real scalar field (with or without a VEV); and a right-handed Type 1 See-Saw Majorana neutrino with M_R >> m_{Higgs}. We prove that for |q^2| <<...

  6. How to fix a broken symmetry: quantum dynamics of symmetry restoration in a ferromagnetic Bose-Einstein condensate

    International Nuclear Information System (INIS)

    Damski, Bogdan; Zurek, Wojciech H

    2008-01-01

    We discuss the dynamics of a quantum phase transition in a spin-1 Bose-Einstein condensate when it is driven from the magnetized broken-symmetry phase to the unmagnetized 'symmetric' polar phase. We determine where the condensate goes out of equilibrium as it approaches the critical point, and compute the condensate magnetization at the critical point. This is done within a quantum Kibble-Zurek scheme traditionally employed in the context of symmetry-breaking quantum phase transitions. Then we study the influence of the non-equilibrium dynamics near a critical point on the condensate magnetization. In particular, when the quench stops at the critical point, nonlinear oscillations of magnetization occur. They are characterized by a period and an amplitude that are inversely proportional. If we keep driving the condensate far away from the critical point through the unmagnetized 'symmetric' polar phase, the amplitude of magnetization oscillations slowly decreases reaching a nonzero asymptotic value. That process is described by an equation that can be mapped onto the classical mechanical problem of a particle moving under the influence of harmonic and 'anti-friction' forces whose interplay leads to surprisingly simple fixed-amplitude oscillations. We obtain several scaling results relating the condensate magnetization to the quench rate, and verify numerically all analytical predictions

  7. Flavour symmetry restoration and kaon weak matrix elements in quenched twisted mass QCD

    CERN Document Server

    Dimopoulos, P; Palombi, Filippo; Peña, C; Sint, S; Vladikas, A

    2007-01-01

    We simulate two variants of quenched twisted mass QCD (tmQCD), with degenerate Wilson quarks of masses equal to or heavier than half the strange quark mass. We use Ward identities in order to measure the twist angles of the theory and thus check the quality of the tuning of mass parameters to a physics condition which stays constant as the lattice spacing is varied. Flavour symmetry breaking in tmQCD is studied in a framework of two fully twisted and two standard Wilson quark flavours, tuned to be degenerate in the continuum. Comparing pseudoscalar masses, obtained from connected quark diagrams made of tmQCD and/or standard Wilson quark propagators, we confirm that flavour symmetry breaking effects, which are at most 5%, decrease as we approach the continuum limit. We also compute the pseudoscalar decay constant in the continuum limit, with reduced systematics. As a consequence of improved tuning of the mass parameters at $\\beta = 6.1$, we reanalyse our previous $B_K$ results. Our main phenomenological findin...

  8. Effect of orbital symmetry on the anisotropic superexchange interaction

    International Nuclear Information System (INIS)

    Kim, Beom Hyun; Min, B I

    2011-01-01

    Employing the microscopic superexchange model incorporating the effect of spin-orbit interaction, we have investigated the Dzyaloshinsky-Moriya (DM) interaction in perovskite transition-metal (TM) oxides and explored the interplay between the DM interaction and the TM-3d orbital symmetry. For d 3 and d 5 systems with isotropic orbital symmetry, the DM vectors are well described by a simple symmetry analysis considering only the bond geometry. In contrast, the DM interaction for d 4 systems with anisotropic orbital symmetry shows slightly different behavior, which does not obey simple symmetry analysis. The direction as well as the strength of the DM vector varies depending on the occupied orbital shape. We have understood this behavior based on the orbital symmetry induced by local crystal field variation.

  9. Confinement, Chiral Symmetry Breaking and it's Restoration using Dual QCD Formalism

    Directory of Open Access Journals (Sweden)

    Punetha Garima

    2018-01-01

    Full Text Available Utilizing the dual QCD model in term of magnetic symmetry structure of non- Abelian gauge theories, the dynamical chiral-symmetry breaking using Schwinger-Dyson equation has been investigated. A close relation among the color confinement and chiralsymmetry breaking has been observed and demonstrated by computing dynamical parameters. The recovery of the chiral symmetry has also been discussed at finite temperature through the variation of quark mass function and quark condensate which gradually decreases with temperature and vanishes suddenly near the critical temperature.

  10. Functional approach for pairing in finite systems: How to define restoration of broken symmetries in Energy Density Functional theory?

    International Nuclear Information System (INIS)

    Hupin, G; Lacroix, D; Bender, M

    2011-01-01

    The Multi-Reference Energy Density Functional (MR-EDF) approach (also called configuration mixing or Generator Coordinate Method), that is commonly used to treat pairing in finite nuclei and project onto particle number, is re-analyzed. It is shown that, under certain conditions, the MR-EDF energy can be interpreted as a functional of the one-body density matrix of the projected state with good particle number. Based on this observation, we propose a new approach, called Symmetry-Conserving EDF (SC-EDF), where the breaking and restoration of symmetry are accounted for simultaneously. We show, that such an approach is free from pathologies recently observed in MR-EDF and can be used with a large flexibility on the density dependence of the functional.

  11. Symmetry restoration at high-temperature in two-color and two-flavor lattice gauge theories

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong-Wan [Department of Physics, College of Science, Swansea University,Singleton Park, SA2 8PP, Swansea, Wales (United Kingdom); Department of Physics, Pusan National University,Busan 46241 (Korea, Republic of); Extreme Physics Institute, Pusan National University,Busan 46241 (Korea, Republic of); Lucini, Biagio; Piai, Maurizio [Department of Physics, College of Science, Swansea University,Singleton Park, SA2 8PP, Swansea, Wales (United Kingdom)

    2017-04-07

    We consider the SU(2) gauge theory with N{sub f}=2 flavors of Dirac fundamental fermions. We study the high-temperature behavior of the spectra of mesons, discretizing the theory on anisotropic lattices, and measuring the two-point correlation functions in the temporal direction as well as screening masses in various channels. We identify the (pseudo-)critical temperature as the temperature at which the susceptibility associated with the Polyakov loop has a maximum. At high temperature both the spin-1 and spin-0 sectors of the light meson spectra exhibit enhanced symmetry properties, indicating the restoration of both the global SU(4) and the axial U(1){sub A} symmetries of the model.

  12. Effect of symmetry breaking on transition strength distributions

    International Nuclear Information System (INIS)

    Mitchell, G.E.; Shriner, J.F. Jr.

    2001-01-01

    The quantum numbers of over 100 states in 30 P have been determined from the ground state to 8 MeV. Previous measurements had provided complete spectroscopy in 26 Al. For these N=Z=odd nuclei, states of isospin T=0 and T=1 coexist at all energies. These spectra provide a unique opportunity to test the effect of symmetry breaking (of the approximate symmetry isospin) on the level statistics and on the transition strength distributions. The level statistics are strongly affected by the small symmetry breaking and the transition strength distributions differ from the Porter-Thomas distribution

  13. Duality symmetries and the Type II string effective action

    International Nuclear Information System (INIS)

    Bergshoeff, E.

    1996-01-01

    We discuss the duality symmetries of Type II string effective actions in nine, ten and eleven dimensions. As a by-product we give a covariant action underlying the ten-dimensional Type IIB supergravity theory. We apply duality symmetries to construct dyonic Type II string solutions in six dimensions and their reformulation as solutions of the ten-dimensional Type IIB theory in ten dimensions. (orig.)

  14. Accidental symmetries and the effective Lagrangian of string theory

    International Nuclear Information System (INIS)

    Ovrut, B.A.

    1989-01-01

    In this paper the relationship between accidental worldsheet symmetries of the string generating functional and target space invariance groups is discussed. Accidental symmetries are used to derive the invariance groups and effective low energy Lagrangian for the bosonic string, and the heterotic string compactified to four-dimensions on Z N orbifolds. The necessity of a new type of Green-Schwarz mechanism, associated with the auxiliary vector field in the four-dimensional N = 1 supergravity multiplet, is shown using these methods

  15. Low-energy parity restoration and unification mass scale within maximal symmetries

    Directory of Open Access Journals (Sweden)

    Ajaya K. Mohanty

    1984-01-01

    Full Text Available We investigate the hierarchy of gauge boson masses in the maximal grand unified theory by studying the renormalization group equations for the running coupling constants associated with the symmetry breaking of SU(16viaSU(12 q×SU(4 l×U(1 |B|−|L| chain. Particular attention is given to the contribution of Higgs scalars to these equations. It is found that the intermediate mass scale ML, associated with right-handed gauge bosons could be as low as 10 3 GeV only for sin 2θ w(M L as high as 0.265 with α s(M L=0.13. In this chain of symmetry breaking, we have also examined the lowest unification mass that is allowed by the low-energy data for sin 2θ w(M L and the assumed gauge hierarchy. This has been done in two cases; first for the case where SU(3 c is vectorial, second, for the case where SU(3 c is axial. In both cases the lowest unification mass scales were found to be 10 13, 10 11, 10 8 and 10 7 GeV for sin 2θ w(M L = 0.22, 0.24, 0.26,and0.265 respectively with α s(M L = 0.13. The implication of these low unification masses on baryon non-conserving processes is also discussed.

  16. Knee functional recovery and limb-to-limb symmetry restoration after anterior cruciate ligament (ACL) rupture and ACL reconstruction

    Science.gov (United States)

    Nawasreh, Zakariya Hussein

    perturbation training using mechanical device provides effects similar to manual perturbation training on knee mechanics, knee functional performance, and neuromuscular activation pattern in patients with ACL rupture. The second aim of this study was to measure whether the mechanical perturbation training provides an effect similar to that of manual perturbation training on gait mechanics, knee functional performance, muscle co-contraction, and neuromuscular activation pattern in athletes with an acute ACL rupture who are managed non-surgically. The findings of this work revealed that mechanical perturbation training provides effects similar to the manual perturbation training on knee kinematics and kinetics during walking and performance-based and patient-reported measures. Gait limb-to-limb asymmetries continue persist after the training regardless of the treatment group which may indicate that patients require participating in an extended rehabilitation program. Additionally, Perturbation training attempts to resolve the neuromuscular deficits and restore a balance in muscle activation and strength between knee flexors and extensors to enhance the dynamic stability of the knee joint. There are moderate to strong relationships between time duration of muscles' activities and the muscle co-contraction that may reflect neuromuscular adaptations to provide dynamic knee stability.

  17. Chiral symmetry and finite temperature effects in quantum theories

    International Nuclear Information System (INIS)

    Larsen, Aa.

    1987-01-01

    A computer simulation of the harmonic oscillator at finite temperature has been carried out, using the Monte Carlo Metropolis algorithm. Accurate results for the energy and fluctuations have been obtained, with special attention to the manifestation of the temperature effects. Varying the degree of symmetry breaking, the finite temperature behaviour of the asymmetric linear model in a linearized mean field approximation has been studied. In a study of the effects of chiral symmetry on baryon mass splittings, reasonable agreement with experiment has been obtained in a non-relativistic harmonic oscillator model

  18. Effects of the symmetry axis orientation of a TI overburden on seismic images

    Science.gov (United States)

    Chang, Chih-Hsiung; Chang, Young-Fo; Tseng, Cheng-Wei

    2017-07-01

    In active tectonic regions, the primary formations are often tilted and subjected to the processes of folding and/or faulting. Dipping formations may be categorised as tilted transverse isotropy (TTI). While carrying out hydrocarbon exploration in areas of orogenic structures, mispositioning and defocusing effects in apparent reflections are often caused by the tilted transverse isotropy of the overburden. In this study, scaled physical modelling was carried out to demonstrate the behaviours of seismic wave propagation and imaging problems incurred by transverse isotropic (TI) overburdens that possess different orientations of the symmetry axis. To facilitate our objectives, zero-offset reflections were acquired from four stratum-fault models to image the same structures that were overlain by a TI (phenolite) slab. The symmetry axis of the TI slab was vertical, tilted or horizontal. In response to the symmetry axis orientations, spatial shifts and asymmetrical diffraction patterns in apparent reflections were observed in the acquired profiles. Given the different orientations of the symmetry axis, numerical manipulations showed that the imaged events could be well described by theoretical ray paths computed by the trial-and-error ray method and Fermat's principle (TERF) method. In addition, outputs of image restoration show that the imaging problems, i.e. spatial shift in the apparent reflections, can be properly handled by the ray-based anisotropic 2D Kirchhoff time migration (RAKTM) method.

  19. Effects of rotational symmetry breaking in polymer-coated nanopores

    Science.gov (United States)

    Osmanović, D.; Kerr-Winter, M.; Eccleston, R. C.; Hoogenboom, B. W.; Ford, I. J.

    2015-01-01

    The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However, simulations have shown that this rotational symmetry can be broken when there are attractive interactions between the polymers. We investigate the phases that emerge in these circumstances, and we quantify the effect of the symmetry assumption on the phase behavior of the system. In the absence of this assumption, one can observe large differences in the equilibrium densities between the rotationally symmetric case and the non-rotationally symmetric case. A simple analytical model is developed that illustrates the driving thermodynamic forces responsible for this symmetry breaking. Our results have implications for the current understanding of the behavior of polymers in cylindrical nanopores.

  20. Effects of rotational symmetry breaking in polymer-coated nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Osmanović, D.; Hoogenboom, B. W.; Ford, I. J. [London Centre for Nanotechnology (LCN) and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Kerr-Winter, M.; Eccleston, R. C. [Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-01-21

    The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However, simulations have shown that this rotational symmetry can be broken when there are attractive interactions between the polymers. We investigate the phases that emerge in these circumstances, and we quantify the effect of the symmetry assumption on the phase behavior of the system. In the absence of this assumption, one can observe large differences in the equilibrium densities between the rotationally symmetric case and the non-rotationally symmetric case. A simple analytical model is developed that illustrates the driving thermodynamic forces responsible for this symmetry breaking. Our results have implications for the current understanding of the behavior of polymers in cylindrical nanopores.

  1. Dynamical chiral symmetry breaking and confinement : its interrelation and effects on the hadron mass spectrum

    International Nuclear Information System (INIS)

    Schröck, M.

    2013-01-01

    Within the framework of this thesis, the interrelation between the two characteristic phenomena of quantum chromodynamics (QCD), i.e., dynamical chiral symmetry breaking and confinement, is investigated. To this end, we apply lattice gauge field theory techniques and adopt a method to artificially restore the dynamically broken chiral symmetry. The low-mode part of the Dirac eigenspectrum is tied to the dynamical breaking of the chiral symmetry according to the Banks--Casher relation. Utilizing two-flavor dynamical lattice gauge field configurations, we construct valence quark propagators that exclude a variable sized part of the low-mode Dirac spectrum, with the aim of using these as an input for meson and baryon interpolating fields. Subsequently, we explore the behavior of ground and excited states of the low-mode truncated hadrons using the variational analysis method. We look for the existence of confined hadron states and extract effective masses where applicable. Moreover, we explore the evolution of the quark wavefunction renormalization function and the renormalization point invariant mass function of the quark propagator under Dirac low-mode truncation in a gauge fixed setting. Motivated by the necessity of fixing the gauge in the aforementioned study of the quark propagator, we also developed a flexible high performance code for lattice gauge fixing, accelerated by graphic processing units (GPUs) using NVIDIA CUDA (Compute Unified Device Architecture). Lastly, more related but unpublished work on the topic is presented. This includes a study of the locality violation of low-mode truncated Dirac operators, a discussion of the possible extension of the low-mode truncation method to the sea quark sector based on a reweighting scheme, as well as the presentation of an alternative way to restore the dynamically broken chiral symmetry. (author) [de

  2. TOPICAL REVIEW: Tunneling magnetoresistance from a symmetry filtering effect

    Directory of Open Access Journals (Sweden)

    William H Butler

    2008-01-01

    Full Text Available This paper provides a brief overview of the young, but rapidly growing field of spintronics. Its primary objective is to explain how as electrons tunnel through simple insulators such as MgO, wavefunctions of certain symmetries are preferentially transmitted. This symmetry filtering property can be converted into a spin-filtering property if the insulator is joined epitaxially to a ferromagnetic electrode with the same two-dimensional symmetry parallel to the interface. A second requirement of the ferromagnetic electrodes is that a wavefunction with the preferred symmetry exists in one of the two spin channels but not in the other. These requirements are satisfied for electrons traveling perpendicular to the interface for Fe–MgO–Fe tunnel barriers. This leads to a large change in the resistance when the magnetic moment of one of the electrodes is rotated relative to those of the other electrode. This large tunneling magnetoresistance effect is being used as the read sensor in hard drives and may form the basis for a new type of magnetic memory.

  3. Composite symmetry-protected topological order and effective models

    Science.gov (United States)

    Nietner, A.; Krumnow, C.; Bergholtz, E. J.; Eisert, J.

    2017-12-01

    Strongly correlated quantum many-body systems at low dimension exhibit a wealth of phenomena, ranging from features of geometric frustration to signatures of symmetry-protected topological order. In suitable descriptions of such systems, it can be helpful to resort to effective models, which focus on the essential degrees of freedom of the given model. In this work, we analyze how to determine the validity of an effective model by demanding it to be in the same phase as the original model. We focus our study on one-dimensional spin-1 /2 systems and explain how nontrivial symmetry-protected topologically ordered (SPT) phases of an effective spin-1 model can arise depending on the couplings in the original Hamiltonian. In this analysis, tensor network methods feature in two ways: on the one hand, we make use of recent techniques for the classification of SPT phases using matrix product states in order to identify the phases in the effective model with those in the underlying physical system, employing Künneth's theorem for cohomology. As an intuitive paradigmatic model we exemplify the developed methodology by investigating the bilayered Δ chain. For strong ferromagnetic interlayer couplings, we find the system to transit into exactly the same phase as an effective spin-1 model. However, for weak but finite coupling strength, we identify a symmetry broken phase differing from this effective spin-1 description. On the other hand, we underpin our argument with a numerical analysis making use of matrix product states.

  4. Electron correlation effects in the presence of non-symmetry dictated ...

    Indian Academy of Sciences (India)

    We numerically study the effect of non-symmetry dictated nodes (NSDN) on electron ... the absence of NSDN, attractive interaction between electrons give such an ... and the violation of parity effect, we first explain what are symmetry dictated.

  5. Radioecological restoration by natural effects

    International Nuclear Information System (INIS)

    Muck, K.

    2002-01-01

    A number of proposals have been put forward to reduce the long-term exposure of the population in areas contaminated after an accident in a nuclear power plant, a reprocessing plant or other accidental releases of activity to the environment, in particular with regard to long-lived radionuclides such as 9 0S r and 1 37C s. Each of these countermeasures incorporates a more or less significant negative impact on the population. Probably the most detrimental impact results from the resettlement of the population from a contaminated territory, both because of the social and psychological problems and the economic detriment involved. But also other countermeasures proposed to reduce the internal dose such as soil top layer removal, deep plowing or chemical treatment of the soil may have a significant, negative impact on the land. If they can be avoided, the impact on the population and the land would certainly be less. In that respect, it is well known that the bio-availability of both 9 0S r and 1 37C s for uptake by plants and thus in foodstuffs is reduced by natural effects far quicker than the corresponding half-life of these radionuclides would imply. These natural effects which are basically due to the increasing fixation of 9 0S r and 1 37C s in the soil, penetration into deeper soil layers and activity removal processes from bio-mass, show no influence or harm to the soil as they are occurring without any artificial measures to remediate the soil

  6. Restorative effects of virtual nature settings.

    Science.gov (United States)

    Valtchanov, Deltcho; Barton, Kevin R; Ellard, Colin

    2010-10-01

    Previous research regarding the potential benefits of exposing individuals to surrogate nature (photographs and videos) has found that such immersion results in restorative effects such as increased positive affect, decreased negative affect, and decreased stress. In the current experiment, we examined whether immersion in a virtual computer-generated nature setting could produce restorative effects. Twenty-two participants were equally divided between two conditions, while controlling for gender. In each condition, participants performed a stress-induction task, and were then immersed in virtual reality (VR) for 10 minutes. The control condition featured a slide show in VR, and the nature experimental condition featured an active exploration of a virtual forest. Participants in the nature condition were found to exhibit increased positive affect and decreased stress after immersion in VR when compared to those in the control condition. The results suggest that immersion in virtual nature settings has similar beneficial effects as exposure to surrogate nature. These results also suggest that VR can be used as a tool to study and understand restorative effects.

  7. Effect of Symmetry Improvement in Weight Bearing on Postural Stability of Hemiparetic Patients

    Directory of Open Access Journals (Sweden)

    Hossein Asghar-Hosseini

    2008-07-01

    Full Text Available Objective: Impaired postural control has been known as the main cause of fall in hemiparesis after stroke. Is Asymmetry of weight bearing on lower limb is one of the prominent characteristics of postural imbalance in these patients. The aim of this study was to evaluate the effect of symmetry improvement in weight bearing through therapeutic interventions on postural stability in hemiparetic patients. Materials & Methods: In this quasi – experimental study which 27 hemiparetic patients were selected through sample of convenience by simple method from men and women who were referred to neurology clinic of Hazrat-e-Rasool hospital. For postural assessment patients stood quietly with open eyes and close eyes on force plates. Primary assessments included evaluation of asymmetry index (AI, RMS COP displacement (Root Mean Square of Center of Pressure and RMS COP velocity in both frontal and sagital planes. Then a 10mm lift was inserted under the unaffected limb and primary assessments were repeated. Data were analyzed by repeated measure ANOVA test. Results: Simple main effect of lift on asymmetry index was significant (P<0/0001. There was no significant interaction between vision and lift. Simple main effect of lift on postural stability variables was also non significant (for RMS COP displacement in frontal and sagital planes P=0.186 and P=0.245, respectively and for RMS COP velocity P=0.259 and P=0.342 respectively. Conclusion: Inserting a lift can improve symmetry by shifting center of gravity to midline. Since symmetry improvement did not decrease postural instability, asymmetric weight bearing can not be the primary cause of postural instability and may not be the principal target of rehabilitation programs aiming at restoring standing balance after stroke.

  8. Effects of Initial Symmetry on the Global Symmetry of One-Dimensional Legal Cellular Automata

    Directory of Open Access Journals (Sweden)

    Ikuko Tanaka

    2015-09-01

    Full Text Available To examine the development of pattern formation from the viewpoint of symmetry, we applied a two-dimensional discrete Walsh analysis to a one-dimensional cellular automata model under two types of regular initial conditions. The amount of symmetropy of cellular automata (CA models under regular and random initial conditions corresponds to three Wolfram’s classes of CAs, identified as Classes II, III, and IV. Regular initial conditions occur in two groups. One group that makes a broken, regular pattern formation has four types of symmetry, whereas the other group that makes a higher hierarchy pattern formation has only two types. Additionally, both final pattern formations show an increased amount of symmetropy as time passes. Moreover, the final pattern formations are affected by iterations of base rules of CA models of chaos dynamical systems. The growth design formations limit possibilities: the ratio of developing final pattern formations under a regular initial condition decreases in the order of Classes III, II, and IV. This might be related to the difference in degree in reference to surrounding conditions. These findings suggest that calculations of symmetries of the structures of one-dimensional cellular automata models are useful for revealing rules of pattern generation for animal bodies.

  9. Partial restoration of spin-isospin SU(4) symmetry and the one-quasiparticle random-phase approximation method in double-β decay

    Science.gov (United States)

    Ferreira, V. dos S.; Krmpotić, F.; Barbero, C. A.; Samana, A. R.

    2017-10-01

    The one-quasiparticle random-phase approximation (one-QRPA) method is used to describe simultaneously both double-β -decay modes, giving special attention to the partial restoration of spin-isospin SU(4 ) symmetry. To implement this restoration and to fix the model parameters, we resort to the energetics of Gamow-Teller resonances and to the minima of the single-β+-decay strengths. This makes the theory predictive regarding the β β2 ν decay, producing the 2 ν moments in 48Ca, 76Ge, 82Se, 96Zr, 100Mo, Te,130128, and 150Nd, that are of the same order of magnitude as the experimental ones; however, the agreement with β β2 ν data is only modest. To include contributions coming from induced nuclear weak currents, we extend the β β0 ν -decay formalism employed previously in C. Barbero et al., Nucl. Phys. A 628, 170 (1998), 10.1016/S0375-9474(97)00614-3, which is based on the Fourier-Bessel expansion. The numerical results for the β β0 ν moments in the above mentioned nuclei are similar to those obtained in other theoretical studies although smaller on average by ˜40 % . We attribute this difference basically to the one-QRPA method, employed here for the first time, instead of the currently used two-QRPA method. The difference is partially due also to the way of carrying out the restoration of the spin-isospin symmetry. It is hard to say which is the best way to make this restoration, since the β β0 ν moments are not experimentally measurable. The recipe proposed here is based on physically robust arguments. The numerical uncertainties in the β β moments, related to (i) their strong dependence on the residual interaction in the particle-particle channel when evaluated within the QRPA, and (ii) lack of proper knowledge of single-particle energies, have been quantified. It is concluded that the partial restoration of the SU(4 ) symmetry, generated by the residual interaction, is crucial in the description of the β β decays, regardless of the nuclear

  10. Interaction potentials and their effect on crystal nucleation and symmetry

    International Nuclear Information System (INIS)

    Hsu, C.S.; Rahman, A.

    1979-01-01

    Molecular dynamics technique has been used to study the effect of the interaction potential on crystal nucleation and the symmetry of the nucleated phase. Four systems, namely rubidium, Lennard-Jones, rubidium-truncated, and Lennard-Jones-truncated, have been studied each at reduced density 0.95. Two types of calculations were performed. Firstly, starting from a liquid state, each system was quenched rapidly to a reduced temperature of approx.0.1. The nucleation process for these systems was monitored by studying the time dependence of temperature and the pair correlation function, and the resulting crystalline structure analyzed using among other properties the Voronoi polyhedra. Only in the case of rubidium was a b.c.c. structure nucleated. In the other three cases we obtained a f.c.c. ordering. Secondly, we have studied the effect of changing the interaction potential in a system which has already achieved an ordered state under the action of some other potential. After establishing a b.c.c. structure in a rubidium system, the change in the symmetry of the system was studied when the pair potential was modified to one of the other three forms. The results from both types of calculations are consistent: the rubidium potential leads to a b.c.c. structure while the other three potentials give an f.c.c. structure. Metastable disordered structures were not obtained in any of the calculations. However, the time elapse between the moment when the system is quick-quenched and the moment when nucleation occurs appears to depend upon the potential of interaction

  11. Hair restoration.

    Science.gov (United States)

    Rawnsley, Jeffrey D

    2008-08-01

    The impact of male hair loss as a personal and social marker of aging is tremendous and its persistence as a human concern throughout recorded history places it in the forefront of male concern about the physical signs of aging. Restoration of the frontal hairline has the visual effect of re-establishing facial symmetry and turning back time. Follicular unit transplantation has revolutionized hair restoration, with its focus on redistributing large numbers of genetically stable hair to balding scalp in a natural distribution. Follicular unit hair restoration surgery is a powerful tool for the facial plastic surgeon in male aesthetic facial rejuvenation because it offers high-impact, natural-appearing results with minimal downtime and risk for adverse outcome.

  12. Medium modifications of mesons. Chiral symmetry restoration, in-medium QCD sum rules for D and ρ mesons, and Bethe-Salpeter equations

    Energy Technology Data Exchange (ETDEWEB)

    Hilger, Thomas Uwe

    2012-04-11

    The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D- anti D and B- anti B mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D{sub s} and D{sup *}{sub 0} mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the ρ meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpeter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

  13. HDACi: cellular effects, opportunities for restorative dentistry.

    LENUS (Irish Health Repository)

    Duncan, H F

    2011-12-01

    Acetylation of histone and non-histone proteins alters gene expression and induces a host of cellular effects. The acetylation process is homeostatically balanced by two groups of cellular enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs). HAT activity relaxes the structure of the human chromatin, rendering it transcriptionally active, thereby increasing gene expression. In contrast, HDAC activity leads to gene silencing. The enzymatic balance can be \\'tipped\\' by histone deacetylase inhibitors (HDACi), leading to an accumulation of acetylated proteins, which subsequently modify cellular processes including stem cell differentiation, cell cycle, apoptosis, gene expression, and angiogenesis. There is a variety of natural and synthetic HDACi available, and their pleiotropic effects have contributed to diverse clinical applications, not only in cancer but also in non-cancer areas, such as chronic inflammatory disease, bone engineering, and neurodegenerative disease. Indeed, it appears that HDACi-modulated effects may differ between \\'normal\\' and transformed cells, particularly with regard to reactive oxygen species accumulation, apoptosis, proliferation, and cell cycle arrest. The potential beneficial effects of HDACi for health, resulting from their ability to regulate global gene expression by epigenetic modification of DNA-associated proteins, also offer potential for application within restorative dentistry, where they may promote dental tissue regeneration following pulpal damage.

  14. Symmetry Energy Effects in the Neutron Star Properties

    Science.gov (United States)

    Alvarez-Castillo, D. E.; Kubis, S.

    2012-12-01

    The functional form of the nuclear symmetry energy has only been determined in a very narrow range of densities. Uncertainties concern both the low as well as the high density behaviour of this function. In this work different shapes of the symmetry energy, consistent with the experimental data, were introduced and their consequences for the crustal properties of neutron stars are presented. The resulting models are in agreement with astrophysical observations.

  15. Correlation and symmetry effects in transport through an artificial molecule

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, F. [Posgrado en Fisica de Materiales, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Ensenada, Baja California (Mexico); Cota, E. [Centro de Ciencias de la Materia Condensada-UNAM, Ensenada, Baja California (Mexico); Ulloa, S.E. [Department of Physics and Astronomy and Condensed Matter and Surface Sciences Program, Ohio University, Athens, Ohio 45701-2979 (United States)

    1999-02-01

    Spectral weights and current-voltage characteristics of an artificial diatomic molecule are calculated, considering cases where the dots connected in series are in general different. The spectral weights allow us to understand the effects of correlations, their connection with selection rules for transport, and the role of excited states in the experimental conductance spectra of these coupled double dot systems (DDS). An extended Hubbard Hamiltonian with varying interdot tunneling strength is used as a model, incorporating quantum confinement in the DDS, interdot tunneling as well as intra- and interdot Coulomb interactions. We find that interdot tunneling values determine to a great extent the resulting eigenstates and corresponding spectral weights. Details of the state correlations strongly suppress most of the possible conduction channels, giving rise to effective selection rules for conductance through the molecule. Most states are found to make insignificant contributions to the total current for finite biases. We find also that the symmetry of the structure is reflected in the I-V characteristics, and is in qualitative agreement with experiment. {copyright} {ital 1999} {ital The American Physical Society}

  16. Restoring the azimuthal symmetry of lateral distributions of charged particles in the range of the KASCADE-Grande experiment

    International Nuclear Information System (INIS)

    Sima, O.; Rebel, H.; Haungs, A.; Toma, G.; Manailescu, C.; Morariu, C.; Arteaga, J.C.; Bekk, K.; Bertaina, M.; Bluemer, J.; Bozdog, H.; Brancus, I.M.; Chiavassa, A.; Cosavella, F.; Souza, V. de; Doll, P.; Engel, R.; Finger, M.; Glasstetter, R.; Grupen, C.

    2011-01-01

    The reconstruction of Extensive Air Showers (EAS) observed by particle detectors at the ground is based on the characteristics of observables like the lateral particle density and the arrival times. The lateral densities, inferred for different EAS components from detector data, are usually parameterised by applying various lateral distribution functions (LDFs). The LDFs are used in turn for evaluating quantities like the total number of particles or the density at particular radial distances. Typical expressions for LDFs anticipate azimuthal symmetry of the density around the shower axis. The deviations of the lateral particle density from this assumption arising from various reasons are smoothed out in the case of compact arrays like KASCADE, but not in the case of arrays like Grande, which only sample a smaller part of the azimuthal variation. KASCADE-Grande, an extension of the former KASCADE experiment, is a multi-component Extensive Air Shower (EAS) experiment located at the Karlsruhe Institute of Technology (Campus North), Germany. The lateral distributions of charged particles are deduced from the basic information provided by the Grande scintillators - the energy deposits - first in the observation plane, then in the intrinsic shower plane. In all steps azimuthal dependences should be taken into account. As the energy deposit in the scintillators is dependent on the angles of incidence of the particles, azimuthal dependences are already involved in the first step: the conversion from the energy deposits to the charged particle density. This is done by using the Lateral Energy Correction Function (LECF) that evaluates the mean energy deposited by a charged particle taking into account the contribution of other particles (e.g. photons) to the energy deposit. By using a very fast procedure for the evaluation of the energy deposited by various particles we prepared realistic LECFs depending on the angle of incidence of the shower and on the radial and

  17. Progress toward the effective Quantum Chromodynamic Lagrangian from symmetry considerations

    International Nuclear Information System (INIS)

    Salomone, A.N.

    1982-01-01

    The properties of an effective Lagrangian which satisfies both the axial and trace anomaly equations of Quantum Chromodynamics are investigated both from the theoretical and phenomenological points of view. The model Lagrangian requires that chiral symmetry be broken spontaneously. The non-linear approximation of the model illuminates eta-glue duality or mixing. The phase transition behavior of the model of Quantum Chromodynamics can be studied as the numbers of flavors and the vacuum angle are varied by analyzing a simple mechanical analog. The analog of the model is similar to the massive Schwinger model. The possibility of a physical scalar glue state is discussed and it is shown that it is characterized by a pronounced eta to two glue decay width. A nonperturbative Quantum Chromodynamic vacuum is seen to follow directly from satisfying the trace anomaly. The quark matter meson, eta, is at least as prominent as the glueball, iota, in the gluon dominated reaction psi to gamma plus anything. An associated large breaking of flavor SU(3) is shown to be ameliorated as the model is made more realistic by lowering scalar meson masses from infinity. The pi delta decay of the iota (1440) can be reasonably well estimated without the need of introducing any new parameters

  18. The Effect of a Textured Insole on Symmetry of Turning

    Directory of Open Access Journals (Sweden)

    Etem Curuk

    2018-01-01

    Full Text Available Turning while walking is a common daily activity. Individuals with unilateral impairment frequently perform turns asymmetrically. The purpose of the study was to investigate the effect of a discomfort-inducing textured insole on symmetry of turning. Nine healthy individuals performed turns to the right while walking with no insole, immediately after the insole was inserted in the right shoe, and after walking for six minutes with the insole. The duration of turning, displacements of pelvic markers, and perceived level of discomfort were evaluated. Utilizing the insole was associated with the increased level of perceived discomfort (p<0.05. Moreover, using the insole was linked to changes in the displacement of two pelvic markers and larger asymmetry index while turning immediately after the insole was inserted in the right shoe as compared to no insole condition (p<0.05. The duration of right turning increased immediately after the insole was inserted (p<0.05 and after walking with the insole for six minutes. The results indicate that the textured insole creates asymmetry of turning in healthy individuals. The outcome provides a background for future studies focused on using a textured insole to minimize the asymmetry of turning commonly seen in individuals with unilateral impairment.

  19. Some remarks on chiral symmetry in dense matter

    International Nuclear Information System (INIS)

    Kaellman, C.G.; Montonen, C.

    1982-01-01

    The restoration of chiral symmetry in quantum chromodynamics as the temperature T and the chemical potential vertical stroke μ vertical stroke are increased is discussed qualitatively and using effective field theories. The latter are shown not to give reliable quantitative estimates. It is argued that a dilute gas of instantons cannot be the main dynamical agent responsible for the breakdown of chiral symmetry. (orig.)

  20. Searching for Affective and Cognitive Restoration: Examining the Restorative Effects of Casual Video Game Play.

    Science.gov (United States)

    Rupp, Michael A; Sweetman, Richard; Sosa, Alejandra E; Smither, Janan A; McConnell, Daniel S

    2017-11-01

    We investigated the effects of a passive break, relaxation activity, and casual video game on affect, stress, engagement, and cognitive performance. Reducing stress and improving cognitive performance is critical across many domains. Previous studies investigated taking a break, relaxation techniques, or playing a game; however, these methods have not been compared within a single experiment. Participants completed a baseline affective and cognitive assessment (ACA), which included the Positive and Negative Affect Schedule, shortened version of the Dundee Stress State Questionnaire, and backward digit-span. Next, participants completed a vigilance task, followed by another ACA. Participants were then assigned at random to complete a break or relaxation activity or play a casual video game, followed by a final ACA. Participants who played the casual video game exhibited greater engagement and affective restoration than the relaxation condition. The break condition slightly decreased affect and prevented cognitive restoration. Playing a casual video game even briefly can restore individuals' affective abilities, making it a suitable activity to restore mood in response to stress. However, future research is needed to find activities capable of cognitive restoration. Many activities in life require sustained cognitive demand, which are stressful and decrease performance, especially for workers in performance-critical domains. Our research suggests some leisure activities are better than others for restoring fatigued affective processes.

  1. Symmetries within chaos: A route to effective mixing

    International Nuclear Information System (INIS)

    Franjione, J.G.; Leong, C.; Ottino, J.M.

    1989-01-01

    Experimental studies show that simple two-dimensional time-periodic flows can produce chaotic mixing. However, the mixing is not always complete; depending on the choice of the period, there can exist large dynamic structures, called islands, that stretch and compress in a time-periodic manner but remain segregated even after long times. Obviously, a flow that contains very few islands is desired. Unfortunately, in most real systems, an analytic expression for the velocity field (or the motion) does not usually exist, making theoretical prediction of the location and size of islands virtually impossible. However, using only minimal knowledge of the gross properties of the velocity field, the flow can be analyzed in terms of its symmetries. Symmetries can be detected without reference to precise mathematical equations. Large islands are located on lines of symmetry, or in pairs on opposite sides of the line. With this knowledge, it is possible to manipulate symmetries in a systematic way so as to move an island into a region of good mixing. Applying this idea repeatedly results in a recursively generated flow history that is neither periodic nor random, but is self-similar. Mixing in these flows is efficient over the entire flow domain. In addition, the idea of recursively generated flow histories might have implications for understanding the mechanisms of turbulent flow

  2. Temperature effects on the nuclear symmetry energy and symmetry free energy with an isospin and momentum dependent interaction

    International Nuclear Information System (INIS)

    Xu, Jun; Ma, Hong-Ru; Chen, Lie-Wen; Li, Bao-An

    2007-01-01

    Within a self-consistent thermal model using an isospin and momentum dependent interaction (MDI) constrained by the isospin diffusion data in heavy-ion collisions, we investigate the temperature dependence of the symmetry energy E sym (ρ,T) and symmetry free energy F sym (ρ,T) for hot, isospin asymmetric nuclear matter. It is shown that the symmetry energy E sym (ρ,T) generally decreases with increasing temperature while the symmetry free energy F sym (ρ,T) exhibits opposite temperature dependence. The decrement of the symmetry energy with temperature is essentially due to the decrement of the potential energy part of the symmetry energy with temperature. The difference between the symmetry energy and symmetry free energy is found to be quite small around the saturation density of nuclear matter. While at very low densities, they differ significantly from each other. In comparison with the experimental data of temperature dependent symmetry energy extracted from the isotopic scaling analysis of intermediate mass fragments (IMF's) in heavy-ion collisions, the resulting density and temperature dependent symmetry energy E sym (ρ,T) is then used to estimate the average freeze-out density of the IMF's

  3. Selecting cost-effective areas for restoration of ecosystem services.

    Science.gov (United States)

    Adame, M F; Hermoso, V; Perhans, K; Lovelock, C E; Herrera-Silveira, J A

    2015-04-01

    Selection of areas for restoration should be based on cost-effectiveness analysis to attain the maximum benefit with a limited budget and overcome the traditional ad hoc allocation of funds for restoration projects. Restoration projects need to be planned on the basis of ecological knowledge and economic and social constraints. We devised a novel approach for selecting cost-effective areas for restoration on the basis of biodiversity and potential provision of 3 ecosystem services: carbon storage, water depuration, and coastal protection. We used Marxan, a spatial prioritization tool, to balance the provision of ecosystem services against the cost of restoration. We tested this approach in a mangrove ecosystem in the Caribbean. Our approach efficiently selected restoration areas that at low cost were compatible with biodiversity targets and that maximized the provision of one or more ecosystem services. Choosing areas for restoration of mangroves on the basis carbon storage potential, largely guaranteed the restoration of biodiversity and other ecosystem services. © 2014 Society for Conservation Biology.

  4. Additivity of Feature-based and Symmetry-based Grouping Effects in Multiple Object Tracking

    Directory of Open Access Journals (Sweden)

    Chundi eWang

    2016-05-01

    Full Text Available Multiple object tracking (MOT is an attentional process wherein people track several moving targets among several distractors. Symmetry, an important indicator of regularity, is a general spatial pattern observed in natural and artificial scenes. According to the laws of perceptual organization proposed by Gestalt psychologists, regularity is a principle of perceptual grouping, such as similarity and closure. A great deal of research reported that feature-based similarity grouping (e.g., grouping based on color, size, or shape among targets in MOT tasks can improve tracking performance. However, no additive feature-based grouping effects have been reported where the tracking objects had two or more features. Additive effect refers to a greater grouping effect produced by grouping based on multiple cues instead of one cue. Can spatial symmetry produce a similar grouping effect similar to that of feature similarity in MOT tasks? Are the grouping effects based on symmetry and feature similarity additive? This study includes four experiments to address these questions. The results of Experiments 1 and 2 demonstrated the automatic symmetry-based grouping effects. More importantly, an additive grouping effect of symmetry and feature similarity was observed in Experiments 3 and 4. Our findings indicate that symmetry can produce an enhanced grouping effect in MOT and facilitate the grouping effect based on color or shape similarity. The where and what pathways might have played an important role in the additive grouping effect.

  5. Restoration of a temperate reef: Effects on the fish community

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Stenberg, Claus; Dahl, Karsten

    2014-01-01

    Trindel in Kattegat, Denmark, has now been re-established with the aim of restoring the reef’s historical structure and function. The effects of the restoration on the local fish community are reported here. Fishing surveys using gillnets and fyke nets were conducted before the restoration (2007) and four...... years after the restoration of the reef (2012). Species of the family Labridae, which have a high affinity for rocky reefs, dominated both before and after the restoration. Commercially important species such as cod Gadus morhua, and saithe Pollachius virens, occurred infrequently in the catches in 2007....... The findings highlight the importance of reef habitats for fish communities and the need for their protection...

  6. Evaluating Visual and Auditory Contributions to the Cognitive Restoration Effect

    Directory of Open Access Journals (Sweden)

    Adam G. Emfield

    2014-06-01

    Full Text Available It has been suggested that certain real-world environments can have a restorative effect on an individual, as expressed in changes in cognitive performance and mood. Much of this research builds on Attention Restoration Theory (ART, which suggests that environments that have certain characteristics induce cognitive restoration via variations in attentional demands. Specifically, natural environments that require little top-down processing have a positive effect on cognitive performance, while city-like environments show no effect. We characterized the cognitive restoration effect further by examining 1 whether natural visual stimuli, such as blue spaces, were more likely to provide a restorative effect over urban visual stimuli, 2 if increasing immersion with environment-related sound produces a similar or superior effect, 3 if this effect extends to other cognitive tasks, such as the functional field of view, and 4 if we could better understand this effect by providing controls beyond previous works. We had 202 participants complete a cognitive task battery, consisting of a reverse digit span task, the attention network task, and the functional field of view task prior to and immediately after a restoration period. In the restoration period, participants were assigned to one of seven conditions in which they listened to natural or urban sounds, watched images of natural or urban environments, or a combination of both. Additionally, some participants were in a control group with exposure to neither picture nor sound. While we found some indication of practice effects, there were no differential effects of restoration observed in any of our cognitive tasks, regardless of condition. We did, however, find evidence that our nature images and sounds were more relaxing than their urban counterparts. Overall, our findings suggest that acute exposure to relaxing pictorial and auditory stimulus is insufficient to induce improvements in cognitive

  7. Effective theory and breakdown of conformal symmetry in a long-range quantum chain

    Science.gov (United States)

    Lepori, L.; Vodola, D.; Pupillo, G.; Gori, G.; Trombettoni, A.

    2016-11-01

    We deal with the problem of studying the symmetries and the effective theories of long-range models around their critical points. A prominent issue is to determine whether they possess (or not) conformal symmetry (CS) at criticality and how the presence of CS depends on the range of the interactions. To have a model, both simple to treat and interesting, where to investigate these questions, we focus on the Kitaev chain with long-range pairings decaying with distance as power-law with exponent α. This is a quadratic solvable model, yet displaying non-trivial quantum phase transitions. Two critical lines are found, occurring respectively at a positive and a negative chemical potential. Focusing first on the critical line at positive chemical potential, by means of a renormalization group approach we derive its effective theory close to criticality. Our main result is that the effective action is the sum of two terms: a Dirac action SD, found in the short-range Ising universality class, and an "anomalous" CS breaking term SAN. While SD originates from low-energy excitations in the spectrum, SAN originates from the higher energy modes where singularities develop, due to the long-range nature of the model. At criticality SAN flows to zero for α > 2, while for α limit α → ∞ the ELI is restored. In order to test the validity of the determined effective theory, we compared the two-fermion static correlation functions and the von Neumann entropy obtained from them with the ones calculated on the lattice, finding agreement. These results explain two observed features characteristic of long-range models, the hybrid decay of static correlation functions within gapped phases and the area-law violation for the von Neumann entropy. The proposed scenario is expected to hold in other long-range models displaying quasiparticle excitations in ballistic regime. From the effective theory one can also see that new phases emerge for α model, are not altered. This also shows

  8. Long-Term Effectiveness of a Brief Restorative Justice Intervention.

    Science.gov (United States)

    Kennedy, Joseph L D; Tuliao, Antover P; Flower, KayLee N; Tibbs, Jessie J; McChargue, Dennis E

    2018-06-01

    This research investigated the effectiveness of a brief Restorative Justice Intervention. Probationers who attended a Restorative Justice Intervention ( n = 383) were compared with probationers receiving treatment as usual ( n = 130) over a 2- to 6-year follow-up period. The proportion of individuals who recidivated in the control condition ( n = 89, 68.46%) were higher compared with those who recidivated in the intervention condition ( n = 127, 33.16%; z = 7.04, p restorative justice. Implications of these effects are discussed.

  9. Spontaneous chiral symmetry breaking and effective quark masses in quantum chromodynamics

    International Nuclear Information System (INIS)

    Miransky, V.A.

    1982-01-01

    The ultraviolet asymptotics of the dynamical effective quark mass is determined directly from the equation for the fermion mass function. The indications about the character of the dynamics of the spontaneous chiral symmetry breaking in QCD are obtained

  10. Finite-temperature effective potential of a system with spontaneously broken symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Zemskov, E.P. [Yaroslavl State Technical Univ. (Russian Federation)

    1995-12-01

    A quantum-mechanical system with spontaneously broken symmetry is considered the effective potential is determined, and it is shown that with reduction of temperature the system undergoes a phase transition of the first kind.

  11. Annealing effect on restoration of irradiation steel properties

    International Nuclear Information System (INIS)

    Vishkarev, O.M.; Kolesova, T.N.; Myasnikova, K.P.; Pecherin, A.M.; Shamardin, V.K.

    1986-01-01

    The effect of temperature and annealing time on the restoration of properties of the 15Kh2NMFAA and 15Kh2MFA steels after irradiation at 285 deg with the fluence of 6x10 23 neutr/m 2 (E>0.5 MeV) is studied. Microhardness (H μ ) restoration in the irradiated 15Kh2NMFAA steel is shown to start from 350 deg C annealing temperature. The complete microhardness restoration is observed at the annealing temperature of 500 deg C for 10 hours

  12. Effects of Meaning and Symmetry on Judgments of Size

    DEFF Research Database (Denmark)

    Reber, Rolf; Christensen, Bo T.; Meier, Beat

    2014-01-01

    to be judged as larger than asymmetric numbers (e.g., 43). However, recent research found that symmetric numbers were judged to be smaller than asymmetric numbers. This finding suggests that the mechanisms underlying size judgments may differ in meaningful and meaningless materials. Supporting this notion, we...... showed in Experiment 1 that meaning increased judged size, whereas symmetry decreased judged size. In the next two experiments, we excluded several alternative explanations for the differences in size judgments between meaningful and meaningless materials in earlier studies. This finding contradicts...

  13. Colour-symmetry-breaking effects in hard processes

    International Nuclear Information System (INIS)

    Efremov, A.V.

    1982-01-01

    A possibility of colour symmetry U(1)xSU(3)sub(C) spontaneous breaking and integer-charged quarks is considered. It is argued that one-photon processes are sensitive only to the colour-averaged charges of quarks and gluons. The true charges can be observed in rigid processes involving at least two real photons. The available now experimental data on processes #betta#p → #betta#X, #betta##betta# → jet+jet are in better agreement with the integer-charges than with the standard QCD

  14. The effect of symmetry on resonant and nonresonant photoresponses in a field-effect terahertz detector

    International Nuclear Information System (INIS)

    Sun, J. D.; Qin, H.; Yang, X. X.; Zhang, Z. P.; Li, X. X.; Zhang, X. Y.; Cai, Y.; Wu, D. M.; Zhang, B. S.; Lewis, R. A.; Sun, Y. F.

    2015-01-01

    The effect of the symmetries in the terahertz (THz) field distribution and the field-effect channel on THz photoresponse is examined. Resonant excitation of cavity plasmon modes and nonresonant self-mixing of THz waves are demonstrated in a GaN/AlGaN two-dimensional electron gas with symmetrically designed nanogates, antennas, and filters. We found that the self-mixing signal can be effectively suppressed by the symmetric design and the resonant response benefits from the residual asymmetry. The findings suggest that a single detector may provide both high sensitivity from the self-mixing mechanism and spectral resolution from the resonant response by optimizing the degree of geometrical and/or electronic symmetries

  15. Effective field theory of emergent symmetry breaking in deformed atomic nuclei

    International Nuclear Information System (INIS)

    Papenbrock, T; Weidenmüller, H A

    2015-01-01

    Spontaneous symmetry breaking in non-relativistic quantum systems has previously been addressed in the framework of effective field theory. Low-lying excitations are constructed from Nambu–Goldstone modes using symmetry arguments only. We extend that approach to finite systems. The approach is very general. To be specific, however, we consider atomic nuclei with intrinsically deformed ground states. The emergent symmetry breaking in such systems requires the introduction of additional degrees of freedom on top of the Nambu–Goldstone modes. Symmetry arguments suffice to construct the low-lying states of the system. In deformed nuclei these are vibrational modes each of which serves as band head of a rotational band. (paper)

  16. Effect of the momentum dependence of nuclear symmetry potential on the transverse and elliptic flows

    International Nuclear Information System (INIS)

    Zhang, Lei; Du, Yun; Zuo, Guang-Hua; Gao, Yuan; Yong, Gao-Chan

    2012-01-01

    In the framework of the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model, the effect of the momentum dependence of nuclear symmetry potential on nuclear transverse and elliptic flows in the neutron-rich reaction 132 Sn+ 124 Sn at a beam energy of 400MeV/nucleon is studied. We find that the momentum dependence of nuclear symmetry potential affects the rapidity distribution of the free neutron to proton ratio, the neutron and the proton transverse flows as a function of rapidity. The momentum dependence of nuclear symmetry potential affects the neutron-proton differential transverse flow more evidently than the difference of neutron and proton transverse flows as well as the difference of proton and neutron elliptic flows. It is thus better to probe the symmetry energy by using the difference of neutron and proton flows since the momentum dependence of nuclear symmetry potential is still an open question. And it is better to probe the momentum dependence of nuclear symmetry potential by using the neutron-proton differential transverse flow the rapidity distribution of the free neutron to proton ratio. (orig.)

  17. Various Effects of Sandblasting of Dental Restorative Materials.

    Directory of Open Access Journals (Sweden)

    Goro Nishigawa

    Full Text Available Sandblasting particles which remain on the surfaces of dental restorations are removed prior to cementation. It is probable that adhesive strength between luting material and sandblasting particle remnants might exceed that with restorative material. If that being the case, blasting particles adhere to sandblasted material surface could be instrumental to increasing adhesive strength like underlying bonding mechanism between luting material and silanized particles of tribochemical silica coating-treated surface. We hypothesize that ultrasonic cleaning of bonding surfaces, which were pretreated with sandblasting, may affect adhesive strength of a resin luting material to dental restorative materials.We therefore observed adhesive strength of resin luting material to aluminum oxide was greater than those to zirconia ceramic and cobalt-chromium alloy beforehand. To measure the shear bond strengths of resin luting material to zirconia ceramic and cobalt-chromium alloy, forty specimens of each restorative material were prepared. Bonding surfaces were polished with silicon abrasive paper and then treated with sandblasting. For each restorative material, 40 sandblasted specimens were equally divided into two groups: ultrasonic cleaning (USC group and non-ultrasonic cleaning (NUSC group. After resin luting material was polymerized on bonding surface, shear test was performed to evaluate effect of ultrasonic cleaning of bonding surfaces pretreated with sandblasting on bond strength.For both zirconia ceramic and cobalt-chromium alloy, NUSC group showed significantly higher shear bond strength than USC group.Ultrasonic cleaning of dental restorations after sandblasting should be avoided to retain improved bonding between these materials.

  18. Effective meson lagrangian with chiral and heavy quark symmetries from quark flavor dynamics

    International Nuclear Information System (INIS)

    Ebert, D.; Feldmann, T.; Friedrich, R.; Reinhardt, H.

    1994-06-01

    By bosonization of an extended NJL model we derive an effective meson theory which describes the interplay between chiral symmetry and heavy quark dynamics. This effective theory is worked out in the low-energy regime using the gradient expansion. The resulting effective lagrangian describes strong and weak interactions of heavy B and D mesons with pseudoscalar Goldstone bosons and light vector and axial-vector mesons. Heavy meson weak decay constants, coupling constants and the Isgur-Wise function are predicted in terms of the model parameters partially fixed from the light quark sector. Explicit SU(3) F symmetry breaking effects are estimated and, if possible, confronted with experiment. (orig.)

  19. Effects of symmetry and familiarity on the attractiveness of human faces

    Directory of Open Access Journals (Sweden)

    Mentus Tatjana

    2016-01-01

    Full Text Available The effects of both symmetry (perceptual factor and familiarity (cognitive factor on facial attractiveness were investigated. From the photographs of original slightly asymmetric faces, symmetric left-left (LL and right-right (RR versions were generated. Familiarity was induced in the learning block using the repetitive presentation of original faces. In the test block participants rated the attractiveness of original, previously seen (familiar faces, original, not previously seen faces, and both LL and RR versions of all faces. The analysis of variance showed main effects of symmetry. Post hoc tests revealed that asymmetric original faces were rated as more attractive than both LL and RR symmetric versions. Familiarity doesn’t have a significant main effect, but the symmetry-familiarity interaction was obtained. Additional post hoc tests indicated that facial attractiveness is positively associated with natural slight asymmetry rather than with perfect symmetry. Also, unfamiliar LL symmetric versions were rated as more attractive than familiar LL versions, whereas familiar RR versions were rated as more attractive than RR unfamiliar faces. These results suggested that symmetry (perceptual factor and familiarity (cognitive or memorial factor play differential roles in facial attractiveness, and indicate a relatively stronger effect of the perceptual compared to the cognitive factor. [Projekat Ministarstva nauke Republike Srbije, br. ON179018 i br. ON179033

  20. Relativistic Anandan quantum phase and the Aharonov–Casher effect under Lorentz symmetry breaking effects in the cosmic string spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Bakke, K., E-mail: kbakke@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Furtado, C., E-mail: furtado@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Belich, H., E-mail: belichjr@gmail.com [Departamento de Física e Química, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29060-900, Vitória, ES (Brazil)

    2016-09-15

    From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the violation of the Lorentz symmetry and write an effective metric for the cosmic string spacetime. Then, we investigate the arising of an analogue of the Anandan quantum phase for a relativistic Dirac neutral particle with a permanent magnetic dipole moment in the cosmic string spacetime under Lorentz symmetry breaking effects. Besides, we analyse the influence of the effects of the Lorentz symmetry violation and the topology of the defect on the Aharonov–Casher geometric quantum phase in the nonrelativistic limit.

  1. Effective potential and spontaneous symmetry breaking in the noncommutative φ6 model

    International Nuclear Information System (INIS)

    Barbosa, G.D.

    2004-01-01

    We study the conditions for spontaneous symmetry breaking of the (2+1)-dimensional noncommutative φ 6 model in the small-θ limit. In this regime, considering the model as a cutoff theory, it is reasonable to assume translational invariance as a property of the vacuum state and study the conditions for spontaneous symmetry breaking by an effective potential analysis. An investigation of up to the two-loop level reveals that noncommutative effects can modify drastically the shape of the effective potential. Under reasonable conditions, the nonplanar sector of the theory can become dominant and induce symmetry breaking for values of the mass and coupling constants not reached by the commutative counterpart

  2. Effect of Ecological Restoration on Body Condition of a Predator.

    Directory of Open Access Journals (Sweden)

    Daniel González-Tokman

    Full Text Available Ecological restoration attempts to recover the structure and function of ecosystems that have been degraded by human activities. A crucial test of ecosystem recovery would be to determine whether individuals in restored environments are as healthy as those in conserved environments. However, the impact of restoration on physiology of terrestrial animals has never been tested. Here, we evaluated the effect of two restoration methods on body condition measured as body size, body mass, lipid and muscle content of the spider Nephila clavipes in a tropical dry forest that has suffered chronic disturbance due to cattle grazing. We used experimental plots that had been excluded from disturbance by cattle grazing during eight years. Plots were either planted with native trees (i. e. maximal intervention, or only excluded from disturbance (i. e. minimal intervention, and were compared with control conserved (remnants of original forest and disturbed plots (where cattle is allowed to graze. We predicted (1 better body condition in spiders of conserved and restored sites, compared to disturbed sites, and (2 better body condition in plots with maximal intervention than in plots with minimal intervention. The first prediction was not supported in males or females, and the second prediction was only supported in females: body dry mass was higher in planted than in conserved plots for spiders of both sexes and also higher that in disturbed plots for males, suggesting that plantings are providing more resources. We discuss how different life histories and environmental pressures, such as food availability, parasitism, and competition for resources can explain our contrasting findings in male and female spiders. By studying animal physiology in restoration experiments it is possible to understand the mechanistic basis of ecological and evolutionary processes that determine success of ecological restoration.

  3. Possible roles of Peccei-Quinn symmetry in an effective low energy model

    Science.gov (United States)

    Suematsu, Daijiro

    2017-12-01

    The strong C P problem is known to be solved by imposing Peccei-Quinn (PQ) symmetry. However, the domain wall problem caused by the spontaneous breaking of its remnant discrete subgroup could make models invalid in many cases. We propose a model in which the PQ charge is assigned quarks so as to escape this problem without introducing any extra colored fermions. In the low energy effective model resulting after the PQ symmetry breaking, both the quark mass hierarchy and the CKM mixing could be explained through Froggatt-Nielsen mechanism. If the model is combined with the lepton sector supplemented by an inert doublet scalar and right-handed neutrinos, the effective model reduces to the scotogenic neutrino mass model in which both the origin of neutrino masses and dark matter are closely related. The strong C P problem could be related to the quark mass hierarchy, neutrino masses, and dark matter through the PQ symmetry.

  4. A study of charge symmetry breaking effects in elastic π+-d scattering

    International Nuclear Information System (INIS)

    Rinat, A.S.; Alexander, Y.

    1982-06-01

    We computed external Coulomb and some strong charge symmetry breaking (CSB) effects in π +- d→π +- d. These appear to account for charge asymmetry of differential cross sections, while approximate CSB spoils the agreement. We further report on a critical study of CSB effects extracted from π +- d total cross section differences. (author)

  5. The effect of provisional restoration type on micromovement of implants.

    Science.gov (United States)

    Holst, Stefan; Geiselhoeringer, Hans; Wichmann, Manfred; Holst, Alexandra Ioana

    2008-09-01

    The osseointegration or fibrous encapsulation of immediately loaded dental implants depends largely on the extent of implant micromovement. The impact of acrylic resin or metal-reinforced acrylic resin provisional restorations on this movement is currently unknown. The purpose of this study was to isolate and measure the effect of provisional restoration type on the vertical displacement of adjacent implants under load at 2 locations. Vertical loads ranging from 10-200 N were applied to polymethyl methacrylate resin (n=56) or metal-reinforced acrylic resin provisional restorations (n=56) supported by 4 implants inserted into homogenous artificial bone in a "u-shaped" alignment. Provisional restorations were first loaded in the anterior segment where the provisional restoration was supported by a mesial and distal implant, followed by loading on an extension 8 mm distal to the last implant. Vertical displacement of the 2 implants nearest the load application was measured and recorded using an optical image correlation technique based on photogrammetric principles. Data were subjected to a nonparametric multivariate analysis (generalized Wilcoxon test) and a Mann-Whitney test with a 2-tailed P value (alpha=.05). There was no significant difference in the vertical implant displacement of the 2 provisional restoration groups when they were loaded in the anterior segment. However, when loads were applied to the distal cantilever, metal reinforcement resulted in less vertical displacement of the next-to-last implant. The mean vertical displacement of the next-to-last implant when supporting an acrylic resin provisional restoration increased from 20 microm +/-3 microm (pooled loads of 10-50 N) to 130 microm +/-21 microm (pooled loads of 160-200 N), while the vertical displacement of the implant when retaining a metal-reinforced acrylic resin provisional restoration increased from 10 microm +/-2 microm to 69 microm +/-13 microm under the same loads (Pprovisional

  6. Effects of riparian vegetation development in a restored lowland stream

    NARCIS (Netherlands)

    Vargas-Luna, A.; Crosato, A.; Hoitink, A.J.F.; Groot, J.; Uijttewaal, W.S.J.

    2016-01-01

    This paper presents the morphodynamic effects of riparian vegetation growth in a lowland restored stream. Hydrological series, high-resolution bathymetric data and aerial photographs are combined in the study. The vegetation root system was found to assert a strong control on soil stabilization,

  7. The effect of restorative juvenile justice on future educational outcomes

    NARCIS (Netherlands)

    Rud, I.; van Klaveren, C.; Groot, W.; Maassen van den Brink, H.

    2014-01-01

    In this article, we study the effects of a Dutch restorative justice program for adolescent first-time offenders on early school leaving and years of education attained. Causal statistical estimates are presented using data from a randomized experiment, in which 944 adolescent offenders are randomly

  8. QCD sum rules for D mesons. In-medium effects, chiral symmetry aspects and higher orders

    Energy Technology Data Exchange (ETDEWEB)

    Buchheim, Thomas

    2017-04-11

    Heavy open flavor mesons can serve as probes of hot and dense, strongly interacting matter in heavy-ion collisions suitable to mimic the extreme conditions shortly after the big-bang or in compact stars. Thus, the thorough theoretical investigation of medium modifications of D mesons is of utmost importance for the interpretation of the experimental data. Even at finite thermodynamic parameters, such as temperature and density, the non-perturbative framework of QCD sum rules allows for the determination of hadronic properties which are not accessible in perturbative quantum chromodynamics (QCD). By virtue of the separation of scales, long-range effects of hadrons are related to quark and gluon degrees of freedom, where features of the hadron spectrum are linked to condensates parameterizing the complex QCD ground state. This thesis furnishes the conception and calculus of QCD sum rules with emphasis on in-medium effects which are inevitable when addressing such effects in higher order contributions. In this regard, the notion and implications of medium-specific condensates are elucidated. Motivated by the significant numerical impact of four-quark condensates to the ρ meson sum rule we evaluate, for the first time, the corresponding in-medium mass-dimension 6 terms for D mesons tentatively employing the factorization hypothesis. Four-quark condensates containing heavy-quark operators may be included into the sum rule analysis utilizing the in-medium heavy-quark expansion made available here. Particular quark condensates are potential order parameters of chiral symmetry breaking, which is the mass generating mechanism of QCD giving the essential mass fraction to light hadrons. The interplay of altered spectral properties with changing in-medium QCD condensates, i. e. the chiral order parameters, can be studied with chiral partner sum rules. Although, introduced for light spin-1 mesons we foster their generalization to spin-0 open charm mesons demonstrating their

  9. QCD sum rules for D mesons. In-medium effects, chiral symmetry aspects and higher orders

    International Nuclear Information System (INIS)

    Buchheim, Thomas

    2017-01-01

    Heavy open flavor mesons can serve as probes of hot and dense, strongly interacting matter in heavy-ion collisions suitable to mimic the extreme conditions shortly after the big-bang or in compact stars. Thus, the thorough theoretical investigation of medium modifications of D mesons is of utmost importance for the interpretation of the experimental data. Even at finite thermodynamic parameters, such as temperature and density, the non-perturbative framework of QCD sum rules allows for the determination of hadronic properties which are not accessible in perturbative quantum chromodynamics (QCD). By virtue of the separation of scales, long-range effects of hadrons are related to quark and gluon degrees of freedom, where features of the hadron spectrum are linked to condensates parameterizing the complex QCD ground state. This thesis furnishes the conception and calculus of QCD sum rules with emphasis on in-medium effects which are inevitable when addressing such effects in higher order contributions. In this regard, the notion and implications of medium-specific condensates are elucidated. Motivated by the significant numerical impact of four-quark condensates to the ρ meson sum rule we evaluate, for the first time, the corresponding in-medium mass-dimension 6 terms for D mesons tentatively employing the factorization hypothesis. Four-quark condensates containing heavy-quark operators may be included into the sum rule analysis utilizing the in-medium heavy-quark expansion made available here. Particular quark condensates are potential order parameters of chiral symmetry breaking, which is the mass generating mechanism of QCD giving the essential mass fraction to light hadrons. The interplay of altered spectral properties with changing in-medium QCD condensates, i. e. the chiral order parameters, can be studied with chiral partner sum rules. Although, introduced for light spin-1 mesons we foster their generalization to spin-0 open charm mesons demonstrating their

  10. Effects of the liquid-gas phase transition and cluster formation on the symmetry energy

    International Nuclear Information System (INIS)

    Typel, S.; Wolter, H.H.; Roepke, G.; Blaschke, D.

    2014-01-01

    Various definitions of the symmetry energy are introduced for nuclei, dilute nuclear matter below saturation density and stellar matter, which is found in compact stars or core-collapse supernovae. The resulting differences are exemplified by calculations in a theoretical approach based on a generalized relativistic density functional for dense matter. It contains nucleonic clusters as explicit degrees of freedom with medium-dependent properties that are derived for light clusters from a quantum statistical approach. With such a model the dissolution of clusters at high densities can be described. The effects of the liquid-gas phase transition in nuclear matter and of cluster formation in stellar matter on the density dependence of the symmetry energy are studied for different temperatures. It is observed that correlations and the formation of inhomogeneous matter at low densities and temperatures causes an increase of the symmetry energy as compared to calculations assuming a uniform uncorrelated spatial distribution of constituent baryons and leptons. (orig.)

  11. Dynamical Evolution of an Effective Two-Level System with {\\mathscr{P}}{\\mathscr{T}} Symmetry

    Science.gov (United States)

    Du, Lei; Xu, Zhihao; Yin, Chuanhao; Guo, Liping

    2018-05-01

    We investigate the dynamics of parity- and time-reversal (PT ) symmetric two-energy-level atoms in the presence of two optical and a radio-frequency (rf) fields. The strength and relative phase of fields can drive the system from unbroken to broken PT symmetric regions. Compared with the Hermitian model, Rabi-type oscillation is still observed, and the oscillation characteristics are also adjusted by the strength and relative phase in the region of unbroken PT symmetry. At exception point (EP), the oscillation breaks down. To better understand the underlying properties we study the effective Bloch dynamics and find the emergence of the z components of the fixed points is the feature of the PT symmetry breaking and the projections in x-y plane can be controlled with high flexibility compared with the standard two-level system with PT symmetry. It helps to study the dynamic behavior of the complex PT symmetric model.

  12. Symmetry and symmetry breaking

    International Nuclear Information System (INIS)

    Balian, R.; Lambert, D.; Brack, A.; Lachieze-Rey, M.; Emery, E.; Cohen-Tannoudji, G.; Sacquin, Y.

    1999-01-01

    The symmetry concept is a powerful tool for our understanding of the world. It allows a reduction of the volume of information needed to apprehend a subject thoroughly. Moreover this concept does not belong to a particular field, it is involved in the exact sciences but also in artistic matters. Living beings are characterized by a particular asymmetry: the chiral asymmetry. Although this asymmetry is visible in whole organisms, it seems it comes from some molecules that life always produce in one chirality. The weak interaction presents also the chiral asymmetry. The mass of particles comes from the breaking of a fundamental symmetry and the void could be defined as the medium showing as many symmetries as possible. The texts put together in this book show to a great extent how symmetry goes far beyond purely geometrical considerations. Different aspects of symmetry ideas are considered in the following fields: the states of matter, mathematics, biology, the laws of Nature, quantum physics, the universe, and the art of music. (A.C.)

  13. Chiral pair of Fermi arcs, anomaly cancellation, and spin or valley Hall effects in Weyl metals with broken inversion symmetry

    Science.gov (United States)

    Jang, Iksu; Kim, Ki-Seok

    2018-04-01

    Anomaly cancellation has been shown to occur in broken time-reversal symmetry Weyl metals, which explains the existence of a Fermi arc. We extend this result in the case of broken inversion symmetry Weyl metals. Constructing a minimal model that takes a double pair of Weyl points, we demonstrate the anomaly cancellation explicitly. This demonstration explains why a chiral pair of Fermi arcs appear in broken inversion symmetry Weyl metals. In particular, we find that this pair of Fermi arcs gives rise to either "quantized" spin Hall or valley Hall effects, which corresponds to the "quantized" version of the charge Hall effect in broken time-reversal symmetry Weyl metals.

  14. Symmetry and electromagnetism

    International Nuclear Information System (INIS)

    Fuentes Cobas, L.E.; Font Hernandez, R.

    1993-01-01

    An analytical treatment of electrostatic and magnetostatic field symmetry, as a function of charge and current distribution symmetry, is proposed. The Newmann Principle, related to the cause-effect symmetry relation, is presented and applied to the characterization of simple configurations. (Author) 5 refs

  15. Report of the Primary Outcomes for Gait Mechanics in Men of the ACL-SPORTS Trial: Secondary Prevention With and Without Perturbation Training Does Not Restore Gait Symmetry in Men 1 or 2 Years After ACL Reconstruction.

    Science.gov (United States)

    Capin, Jacob John; Zarzycki, Ryan; Arundale, Amelia; Cummer, Kathleen; Snyder-Mackler, Lynn

    2017-10-01

    °; 2 years: 16° ± 5°) and SAP+PERT (1 year: 16° ± 5°; 2 years: 15° ± 4°) athletes was not different between groups at 1 year (mean difference: -1°; 95% confidence interval [CI], -5° to 2°; p = 0.49) or 2 years (mean difference: 1°; 95% CI, -2° to 4°; p = 0.54). There were no differences between SAP and SAP+PERT athletes regarding the elimination of gait asymmetries, and gait asymmetries persisted to a large degree in both groups 1 and 2 years postoperatively. At 1 year, 11 of 18 SAP and 11 of 20 SAP+PERT athletes walked with truncated knee excursions during weight acceptance (odds ratio: 0.8, p = 0.70) and midstance (SAP 12 of 18, SAP+PERT 12 of 20; odds ratio: 0.8, p = 0.67), whereas at 2 years postoperatively, truncated knee excursions during weight acceptance (SAP seven of 17, SAP+PERT eight of 19; odds ratio: 1.0, p = 0.96) and midstance (SAP five of 17, SAP+PERT 11 of 19; odds ratio: 3.3, p = 0.09) remained prevalent. We found that a comprehensive, progressive return-to-sport training program with or without perturbation was not effective at restoring interlimb symmetry among men 1 or 2 years after ACL reconstruction. Although gait asymmetries improved from 1 to 2 years postoperatively, meaningful asymmetries persisted in both groups. To restore gait symmetry after ACL reconstruction, additional interventions likely are necessary. Level II, therapeutic study.

  16. Polar Kerr effect studies of time reversal symmetry breaking states in heavy fermion superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Schemm, E.R., E-mail: eschemm@alumni.stanford.edu [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Levenson-Falk, E.M. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Kapitulnik, A. [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305 (United States); Department of Physics, Stanford University, Stanford, CA 94305 (United States); Department of Applied Physics, Stanford University, Stanford, CA 94305 (United States); Stanford Institute of Energy and Materials Science, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2017-04-15

    Highlights: • Polar Kerr effect (PKE) probes broken time-reversal symmetry (TRS) in superconductors. • Absence of PKE below Tc in CeCoIn{sub 5} is consistent with dx2-y2 order parameter symmetry. • PKE in the B phase of the multiphase superconductor UPt3 agrees with an E2u model. • Data on URu2Si2 show broken TRS and additional structure in the superconducting state. - Abstract: The connection between chiral superconductivity and topological order has emerged as an active direction in research as more instances of both have been identified in condensed matter systems. With the notable exception of {sup 3}He-B, all of the known or suspected chiral – that is to say time-reversal symmetry-breaking (TRSB) – superfluids arise in heavy fermion superconductors, although the vast majority of heavy fermion superconductors preserve time-reversal symmetry. Here we review recent experimental efforts to identify TRSB states in heavy fermion systems via measurement of polar Kerr effect, which is a direct consequence of TRSB.

  17. Finite size effects and symmetry breaking in the evolution of networks of competing Boolean nodes

    International Nuclear Information System (INIS)

    Liu, M; Bassler, K E

    2011-01-01

    Finite size effects on the evolutionary dynamics of Boolean networks are analyzed. In the model considered, Boolean networks evolve via a competition between nodes that punishes those in the majority. Previous studies have found that large networks evolve to a statistical steady state that is both critical and highly canalized, and that the evolution of canalization, which is a form of robustness found in genetic regulatory networks, is associated with a particular symmetry of the evolutionary dynamics. Here, it is found that finite size networks evolve in a fundamentally different way than infinitely large networks do. The symmetry of the evolutionary dynamics of infinitely large networks that selects for canalizing Boolean functions is broken in the evolutionary dynamics of finite size networks. In finite size networks, there is an additional selection for input-inverting Boolean functions that output a value opposite to the majority of input values. The reason for the symmetry breaking in the evolutionary dynamics is found to be due to the need for nodes in finite size networks to behave differently in order to cooperate so that the system collectively performs as efficiently as possible. The results suggest that both finite size effects and symmetry are fundamental for understanding the evolution of real-world complex networks, including genetic regulatory networks.

  18. Time-reversal symmetry breaking by ac field: Effect of ...

    Indian Academy of Sciences (India)

    deviate from 2 thus signalling on the time-reversal breaking by the ac field. ... is also the parity effect: the enchancement is only present if either P or Q is even. ... analysis (see figure 1) is possible and the ergodic zero-dimensional approx-.

  19. A bifurcation and symmetry discussion of the Sommerfeld effect

    OpenAIRE

    Clerkin, Eoin; Sampaio, Rubens

    2017-01-01

    The Arnold Sommerfeld effect is an intriguing resonance capture and release series of events originally demonstrated in 1902. A single event is studied using a two degree of freedom mathematical model of a motor with imbalance mounted to laterally restricted spring connected cart. For a certain power supplied, in general the motor rotates at a speed consistent with a motor on a rigid base. However at speeds close to the natural frequency of the cart, it seemingly takes on extra oscillations w...

  20. Symmetry effects in neutron scattering from isotopically enriched Se isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Lachkar, J.; Haouat, G.; McEllistrem, M. T.; Patin, Y.; Sigaud, J.; Cocu, F.

    1975-06-01

    Differential cross sections for neutron elastic and inelastic scattering from {sup 76}Se, {sup 78}Se, {sup 80}Se and {sup 82}Se, have been measured at 8-MeV incident neutron energy and from {sup 76}Se and {sup 82}Se at 6- and 10-MeV incident energies. The differences observed in the elastic scattering cross sections are interpretable as the effects of isospin term in the scattering potentials. A full analysis of the elastic scattering data are presented.

  1. The effects of flavour symmetry breaking on hadron matrix elements

    International Nuclear Information System (INIS)

    Cooke, A.N.; Horsley, R.; Pleiter, D.; Zanotti, J.M.

    2012-12-01

    By considering a flavour expansion about the SU(3)-flavour symmetric point, we investigate how flavour-blindness constrains octet baryon matrix elements after SU(3) is broken by the mass difference between the strange and light quarks. We find the expansions to be highly constrained along a mass trajectory where the singlet quark mass is held constant, which proves beneficial for extrapolations of 2+1 flavour lattice data to the physical point. We investigate these effects numerically via a lattice calculation of the flavour-conserving and flavour-changing matrix elements of the vector and axial operators between octet baryon states.

  2. The effects of flavour symmetry breaking on hadron matrix elements

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, A.N.; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe (Japan); Pleiter, D. [Juelich Research Centre (Germany); Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ. (Australia). School of Chemistry and Physics

    2012-12-15

    By considering a flavour expansion about the SU(3)-flavour symmetric point, we investigate how flavour-blindness constrains octet baryon matrix elements after SU(3) is broken by the mass difference between the strange and light quarks. We find the expansions to be highly constrained along a mass trajectory where the singlet quark mass is held constant, which proves beneficial for extrapolations of 2+1 flavour lattice data to the physical point. We investigate these effects numerically via a lattice calculation of the flavour-conserving and flavour-changing matrix elements of the vector and axial operators between octet baryon states.

  3. Relationships Between Potentiation Effects After Ballistic Half-Squats and Bilateral Symmetry.

    Science.gov (United States)

    Suchomel, Timothy J; Sato, Kimitake; DeWeese, Brad H; Ebben, William P; Stone, Michael H

    2016-05-01

    The purposes of this study were to examine the effect of ballistic concentric-only half-squats (COHS) on subsequent squat-jump (SJ) performances at various rest intervals and to examine the relationships between changes in SJ performance and bilateral symmetry at peak performance. Thirteen resistance-trained men performed an SJ immediately and every minute up to 10 min on dual force plates after 2 ballistic COHS repetitions at 90% of their 1-repetition-maximum COHS. SJ peak force, peak power, net impulse, and rate of force development (RFD) were compared using a series of 1-way repeated-measures ANOVAs. The percent change in performance at which peak performance occurred for each variable was correlated with the symmetry index scores at the corresponding time point using Pearson correlation coefficients. Statistical differences in peak power (P = .031) existed between rest intervals; however, no statistically significant pairwise comparisons were present (P > .05). No statistical differences in peak force (P = .201), net impulse (P = .064), and RFD (P = .477) were present between rest intervals. The relationships between changes in SJ performance and bilateral symmetry after the rest interval that produced the greatest performance for peak force (r = .300, P = .319), peak power (r = -.041, P = .894), net impulse (r = -.028, P = .927), and RFD (r = -.434, P = .138) were not statistically significant. Ballistic COHS may enhance SJ performance; however, the changes in performance were not related to bilateral symmetry.

  4. The effect of vertical and horizontal symmetry on memory for tactile patterns in late blind individuals.

    Science.gov (United States)

    Cattaneo, Zaira; Vecchi, Tomaso; Fantino, Micaela; Herbert, Andrew M; Merabet, Lotfi B

    2013-02-01

    Visual stimuli that exhibit vertical symmetry are easier to remember than stimuli symmetric along other axes, an advantage that extends to the haptic modality as well. Critically, the vertical symmetry memory advantage has not been found in early blind individuals, despite their overall superior memory, as compared with sighted individuals, and the presence of an overall advantage for identifying symmetric over asymmetric patterns. The absence of the vertical axis memory advantage in the early blind may depend on their total lack of visual experience or on the effect of prolonged visual deprivation. To disentangle this issue, in this study, we measured the ability of late blind individuals to remember tactile spatial patterns that were either vertically or horizontally symmetric or asymmetric. Late blind participants showed better memory performance for symmetric patterns. An additional advantage for the vertical axis of symmetry over the horizontal one was reported, but only for patterns presented in the frontal plane. In the horizontal plane, no difference was observed between vertical and horizontal symmetric patterns, due to the latter being recalled particularly well. These results are discussed in terms of the influence of the spatial reference frame adopted during exploration. Overall, our data suggest that prior visual experience is sufficient to drive the vertical symmetry memory advantage, at least when an external reference frame based on geocentric cues (i.e., gravity) is adopted.

  5. The effectiveness of groundwater pumping as a restoration technology

    International Nuclear Information System (INIS)

    Doty, C.B.; Travis, C.C.

    1991-05-01

    An in-depth analysis of the effectiveness of pumping groundwater for aquifer restoration was conducted based on: (1) performance records for 16 sites where pumping with the objective of aquifer restoration has been implemented for periods of 2 to 12 years, and (2) recent theoretical and modeling studies. The reduction of aquifer concentrations is the primary indicator of effectiveness of groundwater extraction. However, other indicators of effectiveness such as plume containment, mass reduction, and achievement of specific cleanup goals were also components of the evaluation. Based on our review of performance records and recent theoretical studies, the following can be concluded regarding the use of groundwater pumping for aquifer restoration: (1) Pumping is effective for contaminant mass reduction, plume containment and extraction of groundwater for point-of-use treatment. Its use for attaining these objectives should be encouraged. (2) Groundwater pumping is ineffective for restoring aquifers to health-based levels. This reality needs to be explicitly recognized by regulators. (3) The primary contributors to the ineffectiveness of pumping in meeting cleanup goals are the time-dependent decrease in the rate of desorption of contaminants from contaminated soils and the existence of immobile contaminants either in the non-aqueous phase or trapped in zones of low permeability. (4) Remedial time frames of 2 years to 30 years were predicted at the sites reviewed. Regulators currently maintain that 20 to 40 years may be needed to reach health-based cleanup goals. However, recent modeling studies estimate pump and treat time frames of 100 to 1000 years. 22 refs., 5 figs., 4 tabs

  6. Symmetry-adaptation and selection rules for effective crystal field Hamiltonians

    International Nuclear Information System (INIS)

    Tuszynski, J.A.

    1986-01-01

    The intention of this paper is to systematically derive an effective Hamiltonian in the presence of crystal fields in such a way as to incorporate relativistic effects and higher order perturbation corrections including configuration mixing. This Hamiltonian will then be conveniently represented as a symmetry-adapted series of one- and two-body double tensor operators whose matrix elements will be analyzed for selection rules. 16 references, 4 tables

  7. More on PT-Symmetry in (Generalized Effect Algebras and Partial Groups

    Directory of Open Access Journals (Sweden)

    J. Paseka

    2011-01-01

    Full Text Available We continue in the direction of our paper on PT-Symmetry in (Generalized Effect Algebras and Partial Groups. Namely we extend our considerations to the setting of weakly ordered partial groups. In this setting, any operator weakly ordered partial group is a pasting of its partially ordered commutative subgroups of linear operators with a fixed dense domain over bounded operators. Moreover, applications of our approach for generalized effect algebras are mentioned.

  8. Physics of chiral symmetry breaking

    International Nuclear Information System (INIS)

    Shuryak, E.V.

    1991-01-01

    This subsection of the 'Modeling QCD' Workshop has included five talks. E. Shuryak spoke on 'Recent Progress in Understanding Chiral Symmetry Breaking'; below it is split into two parts: (i) a mini-review of the field and (ii) a brief presentation of the status of the theory of interacting instantons. The next sections correspond to the following talks: (iii) K. Goeke et al., 'Chiral Restoration and Medium Corrections to Nucleon in the NJL Model'; (iv) M. Takizawa and K. Kubodera, 'Study of Meson Properties and Quark Condensates in the NJL Model with Instanton Effects'; (v) G. Klein and A. G. Williams, 'Dynamical Chiral Symmetry Breaking in Dual QCD'; and (vi) R. D. Ball, 'Skyrmions and Baryons.' (orig.)

  9. Cation symmetry effect on the volatility of ionic liquids.

    Science.gov (United States)

    Rocha, Marisa A A; Coutinho, João A P; Santos, Luís M N B F

    2012-09-06

    This work reports the first data for the vapor pressures at several temperatures of the ionic liquids, [C(N/2)C(N/2)im][NTf(2)] (N = 4, 6, 8, 10, 12) measured using a Knudsen effusion apparatus combined with a quartz crystal microbalance. The morphology and the thermodynamic parameters of vaporization derived from the vapor pressures, are compared with those for the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide series, [C(N-1)C(1)im][NTf(2)] (N = 3 - 9, 11, and 13). It was found that the volatility of [C(N/2)C(N/2)im][NTf(2)] series is significantly higher than the asymmetric cation ILs with the same total number of carbons in the alkyl side chains, [C(N-1)C(1)im][NTf(2)]. The observed higher volatility is related with the lower enthalpy of vaporization. The symmetric cation, [C(N/2)C(N/2)im][NTf(2)], presents lower entropies of vaporization compared with the asymmetric [C(N-1)C(1)im][NTf(2)], indicating an increase of the absolute liquid entropy in the symmetric cation ILs, being a reflection of a change of the ion dynamics in the IL liquid phase. Moreover both the enthalpy and entropy of vaporization of the [C(N/2)C(N/2)im][NTf(2)] ILs, present a clear odd-even effect with higher enthalpies/entropies of vaporization for the odd number of carbons in each alkyl chain ([C(3)C(3)im][NTf(2)] and [C(5)C(5)im][NTf(2)]).

  10. Half-integer flux quantum effect in cuprate superconductors - a probe of pairing symmetry

    International Nuclear Information System (INIS)

    Tsuei, C.C.; Kirtley, J.R.; Gupta, A.; Sun, J.Z.; Moler, K.A.; Wang, J.H.

    1996-01-01

    Based on macroscopic quantum coherence effects arising from pair tunneling and flux quantization, a series of tricrystal experiments have been designed and carried out to test the order parameter symmetry in high-T c cuprate superconductors. By using a scanning SQUID microscope, we have directly and non-invasively observed the spontaneously generated half-integer flux quantum effect in controlled-orientation tricrystal cuprate superconducting systems. The presence or absence of the half-integer flux quantum effect as a function of the tricrystal geometry allows us to prove that the order parameter symmetry in the YBCO and Tl2201 systems is consistent with that of the d x 2 -y 2 pair state. (orig.)

  11. Practice makes imperfect: restorative effects of sleep on motor learning.

    Directory of Open Access Journals (Sweden)

    Bhavin R Sheth

    Full Text Available Emerging evidence suggests that sleep plays a key role in procedural learning, particularly in the continued development of motor skill learning following initial acquisition. We argue that a detailed examination of the time course of performance across sleep on the finger-tapping task, established as the paradigm for studying the effect of sleep on motor learning, will help distinguish a restorative role of sleep in motor skill learning from a proactive one. Healthy subjects rehearsed for 12 trials and, following a night of sleep, were tested. Early training rapidly improved speed as well as accuracy on pre-sleep training. Additional rehearsal caused a marked slow-down in further improvement or partial reversal in performance to observed levels below theoretical upper limits derived on the basis of early pre-sleep rehearsal. This decrement in learning efficacy does not occur always, but if and only if it does, overnight sleep has an effect in fully or partly restoring the efficacy and actual performance to the optimal theoretically achieveable level. Our findings re-interpret the sleep-dependent memory enhancement in motor learning reported in the literature as a restoration of fatigued circuitry specialized for the skill. In providing restitution to the fatigued brain, sleep eliminates the rehearsal-induced synaptic fatigue of the circuitry specialized for the task and restores the benefit of early pre-sleep rehearsal. The present findings lend support to the notion that latent sleep-dependent enhancement of performance is a behavioral expression of the brain's restitution in sleep.

  12. Dynamical symmetry breaking of λφ4 theory in the two loop effective potential

    International Nuclear Information System (INIS)

    Yang Jifeng; Ruan Jianhong

    2002-01-01

    The two loop effective potential of massless λφ 4 theory is presented in several regularization and renormalization prescriptions and the dynamical symmetry breaking solution is obtained in the strong-coupling situation in several prescriptions except the Coleman-Weinberg prescription. The beta function in the broken phase becomes negative and the UV fixed point turns out to be a strong-coupling one, and its numeric value varies with the renormalization prescriptions, a detail which is different from the asymptotic-free solution in the one loop case. The symmetry-breaking phase is shown to be an entirely strong-coupling phase. The reason for the relevance of the renormalization prescriptions is shown to be due to the nonperturbative nature of the effective potential. We also reanalyze the two loop effective potential by adopting a differential equation approach based on the understanding that all the quantum field theories are ill-defined formulations of the 'low-energy' effective theories of a complete underlying theory. The relevance of the prescriptions of fixing the local ambiguities to physical properties such as symmetry breaking is further emphasized. We also tentatively propose a rescaling insensitivity argument for fixing the quadratic ambiguities. Some detailed properties of the strongly coupled broken phase and related issues are discussed

  13. Isospin-symmetry-breaking effects in A∼70 nuclei within beyond-mean-field approach

    Energy Technology Data Exchange (ETDEWEB)

    Petrovici, A.; Andrei, O. [National Institute for Physics and Nuclear Engineering, R-077125 Bucharest (Romania)

    2015-02-24

    Particular isospin-symmetry-breaking probes including Coulomb energy differences (CED), mirror energy differences (MED), and triplet energy differences (TED) manifest anomalies in the A∼70 isovector triplets of nuclei. The structure of proton-rich nuclei in the A∼70 mass region suggests shape coexistence and competition between pairing correlations in different channels. Recent results concerning the interplay between isospin-mixing and shape-coexistence effects on exotic phenomena in A∼70 nuclei obtained within the beyond-mean-field complex Excited Vampir variational model with symmetry projection before variation using a realistic effective interaction in a relatively large model space are presented. Excited Vampir predictions concerning the Gamow-Teller β decay to the odd-odd N=Z {sup 66}As and {sup 70}Br nuclei correlated with the pair structure analysis in the T=1 and T=0 channel of the involved wave functions are discussed.

  14. Effect of bleaching on microhardness of esthetic restorative materials.

    Science.gov (United States)

    Malkondu, Özlem; Yurdagüven, Haktan; Say, Esra Can; Kazazoğlu, Ender; Soyman, Mübin

    2011-01-01

    This study evaluated the effect of a high-concentration carbamide peroxide–containing home bleaching system (Opalescence PF) and a hydrogen peroxide–containing over-the-counter bleaching system (Treswhite Supreme) on the microhardness of two nanocomposites (Filtek Supreme XT and Premise) and leucite-reinforced glass ceramic (Empress Esthetic), glass ceramic (Empress 2 layering), and feldspathic porcelain (Matchmaker MC). A total of 100 specimens, 20 of each kind of the restorative materials, 2 mm in thickness and 10 mm in diameter, were fabricated. Then the specimens were polished with SiC paper and 1 μm alumina polishing paste. After polishing, porcelain specimens were glazed in accordance with the manufacturer's instructions. Each type of restorative material was then randomly divided into two groups (n=10), and the specimens were treated with either Opalescence PF or Treswhite Supreme. The microhardness of the specimens before bleaching (baseline) and after bleaching was determined using a digital microhardness tester. Data were analyzed using the Mann-Whitney U-test and the Wilcoxon test. Opalescence PF significantly influenced the hardness of all the restorative materials. Statistically significant decreases with respect to before bleaching were found for Premise (p=0.005), Empress Esthetic (p=0.003), Empress 2 layering (p=0.005), and Matchmaker-MC (p=0.003), whereas a statistically significant increase was observed in Filtek Supreme XT (p=0.028). The difference in the microhardness values between before and after bleaching using Treswhite Supreme was statistically significant only for Premise (p=0.022). High-concentration carbamide peroxide–containing home bleaching may affect the microhardness of restorative materials.

  15. Isospin splitting of nucleon effective mass and symmetry energy in isotopic nuclear reactions

    Science.gov (United States)

    Guo, Ya-Fei; Chen, Peng-Hui; Niu, Fei; Zhang, Hong-Fei; Jin, Gen-Ming; Feng, Zhao-Qing

    2017-10-01

    Within an isospin and momentum dependent transport model, the dynamics of isospin particles (nucleons and light clusters) in Fermi-energy heavy-ion collisions are investigated for constraining the isospin splitting of nucleon effective mass and the symmetry energy at subsaturation densities. The impacts of the isoscalar and isovector parts of the momentum dependent interaction on the emissions of isospin particles are explored, i.e., the mass splittings of and (). The single and double neutron to proton ratios of free nucleons and light particles are thoroughly investigated in the isotopic nuclear reactions of 112Sn+112Sn and 124Sn+124Sn at incident energies of 50 and 120 MeV/nucleon, respectively. It is found that both the effective mass splitting and symmetry energy impact the kinetic energy spectra of the single ratios, in particular at the high energy tail (larger than 20 MeV). The isospin splitting of nucleon effective mass slightly impacts the double ratio spectra at the energy of 50 MeV/nucleon. A soft symmetry energy with stiffness coefficient of γ s=0.5 is constrained from the experimental data with the Fermi-energy heavy-ion collisions. Supported by Major State Basic Research Development Program in China (2014CB845405, 2015CB856903), National Natural Science Foundation of China (11722546, 11675226, 11675066, U1332207) and Youth Innovation Promotion Association of Chinese Academy of Sciences

  16. Restoration of symmetry by temperature effect under influence of external electro magnetic field in gauge theory

    International Nuclear Information System (INIS)

    Aquino, V.M. de.

    1987-01-01

    We have analysed, within a semi classical approach, the influence of external electromagnetic field on phase transitions in gauge theories. The critical temperature was calculated for an Abelian case, scalar electrodynamics, and for an non Abelian case, the Weinberg Salam model. (author)

  17. Effects of momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei

    International Nuclear Information System (INIS)

    Li Baoan; Das, Champak B.; Das Gupta, Subal; Gale, Charles

    2004-01-01

    Using an isospin- and momentum-dependent transport model we study effects of the momentum-dependent symmetry potential on heavy-ion collisions induced by neutron-rich nuclei. It is found that symmetry potentials with and without the momentum-dependence but corresponding to the same density-dependent symmetry energy E sym (ρ) lead to significantly different predictions on several E sym (ρ)-sensitive experimental observables especially for energetic nucleons. The momentum- and density-dependence of the symmetry potential have to be determined simultaneously in order to extract the E sym (ρ) accurately. The isospin asymmetry of midrapidity nucleons at high transverse momenta is particularly sensitive to the momentum-dependence of the symmetry potential. It is thus very useful for investigating accurately the equation of state of dense neutron-rich matter

  18. Symmetry breaking, and the effect of matter density on neutrino oscillation

    Science.gov (United States)

    Mohseni Sadjadi, H.; Khosravi Karchi, A. P.

    2018-04-01

    A proposal for the neutrino mass, based on neutrino-scalar field interaction, is introduced. The scalar field is also non-minimally coupled to the Ricci scalar, and hence relates the neutrino mass to the matter density. In a dense region, the scalar field obeys the Z2 symmetry, and the neutrino is massless. In a dilute region, the Z2 symmetry breaks and neutrino acquires mass from the non-vanishing expectation value of the scalar field. We consider this scenario in the framework of a spherical dense object whose outside is a dilute region. In this background, we study the neutrino flavors oscillation, along with the consequences of the theory on oscillation length and MSW effect. This preliminary model may shed some lights on the existing anomalies within the neutrino data, concerning the different oscillating behavior of the neutrinos in regions with different densities.

  19. Collarless metal ceramic restorations to obscure the umbrella effect

    Directory of Open Access Journals (Sweden)

    Afroz Shaista

    2010-01-01

    Full Text Available Esthetics with porcelain fused to metal restoration in the anterior region can be adversely affected due to the inadequate teeth preparations and design of the prosthesis. We presented here a case report where esthetics was compromised due to darkening of the interdental papilla and marginal gingival and overcontoured restorations in relation to porcelain fused to metal restorations. Good esthetic results were obtained by using basic principles of tooth preparation and using collarless metal ceramic restorations.

  20. The effect of peatland drainage and restoration on Odonata species richness and abundance.

    Science.gov (United States)

    Elo, Merja; Penttinen, Jouni; Kotiaho, Janne S

    2015-04-09

    Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration efforts. Here, we studied how abundance and species richness of Odonata (dragonflies and damselflies) respond to restoration. We sampled larvae in three sites (restored, drained, pristine) on each of 12 different study areas. We sampled Odonata larvae before restoration (n = 12), during the first (n = 10) and the third (n = 7) year after restoration and used generalized linear mixed models to analyze the effect of restoration. Drained sites had lower abundance and species richness than pristine sites. During the third year after restoration both abundance and species richness had risen in restored sites. Our results show that Odonata suffer from drainage, but seem to benefit from peatland restoration and are able to colonize newly formed water pools already within three years after restoration.

  1. On the effect of scalar partons at short distances in unified theories with spontaneously broken colour symmetry

    International Nuclear Information System (INIS)

    Craigie, N.S.; Salam, Abdus

    1979-05-01

    The effect of scalar partons arising in QCD if the colour symmetry is spontaneously broken is discussed. The authors use a previous result, which states that such scalars can be incorporated into the theory without disturbing asymptotic freedom. (author)

  2. The role of benthic microhabitats in determining the effects of hydromorphological river restoration on macroinvertebrates

    NARCIS (Netherlands)

    Verdonschot, R.C.M.; Kail, Jochem; McKie, Brendan G.; Verdonschot, P.F.M.

    2016-01-01

    Despite the large number of river restoration projects carried out worldwide, evidence for strong and long-term positive ecological effects of hydromorphological restoration on macroinvertebrates is scarce. To improve the understanding of the success and failure of restoration measures, a

  3. Effects of river restoration on riparian ground beetles (Coleoptera Carabidae) in Europe

    NARCIS (Netherlands)

    Januschke, Kathrin; Verdonschot, R.C.M.

    2016-01-01

    Studies addressing the effects of river and floodplain restoration on riparian ground beetles mainly focus on single river sections or regions. We conducted a large-scale study of twenty paired restored and degraded river sections throughout Europe. It was tested (i) if restoration had an overall

  4. Fluorides leaching from restorative materials and the effect on adjacent teeth

    DEFF Research Database (Denmark)

    Qvist, Vibeke; Poulsen, Agneta; Teglers, Poul Thorpen

    2010-01-01

    Placing a Class II restoration in a tooth changes the local environment, including that for the adjacent tooth. Apart from the change to a less- or non-cariogenic environment for the restored tooth, the effect of leachable components from a restoration in the adjacent tooth should be taken into c...

  5. The effect of peatland drainage and restoration on Odonata species richness and abundance

    OpenAIRE

    Elo, Merja; Penttinen, Jouni; Kotiaho, Janne Sakari

    2015-01-01

    Background Restoration aims at reversing the trend of habitat degradation, the major threat to biodiversity. In Finland, more than half of the original peatland area has been drained, and during recent years, restoration of some of the drained peatlands has been accomplished. Short-term effects of the restoration on peatland hydrology, chemistry and vegetation are promising but little is known about how other species groups apart from vascular plants and bryophytes respond to restoration effo...

  6. Environmental restoration by natural effects - Advantages and limits

    International Nuclear Information System (INIS)

    Mueck, K.

    2002-01-01

    After a major contamination of a territory due to fallout from a reactor accident, a reprocessing plant accident or a weapon's detonation one of the important questions to be addressed is the time period required for the countermeasures to be applied. This is particularly important for countermeasures with high costs and consequences to the involved population such as relocation. Therefore, the time period required for a contamination with long-lived fission products to decrease below established intervention levels by natural processes of decay and removal from the soil layer relevant to the exposure is investigated. Natural processes which result in a decrease in activity concentrations in foodstuffs and external exposure, are the least detrimental to a territory as compared to other long-term countermeasures and therefore, the most favorable in that respect. The influence of the contribution of different foodstuffs on the time-span required until a resettlement of a dislocated population is feasible, is assessed and the advantages and limits of natural restoration effects on the required intervention periods are discussed. It is shown that natural restoration effects may contribute substantially to an environmentally safe and sustainable resettlement of an area substantially contaminated with fission products. (author)

  7. Restoring effective sleep tranquility (REST): A feasibility and pilot study.

    Science.gov (United States)

    Eakman, Aaron M; Schmid, Arlene A; Henry, Kimberly L; Rolle, Natalie R; Schelly, Catherine; Pott, Christine E; Burns, Joshua E

    2017-06-01

    The purpose of this pilot study was to establish the feasibility of completing a future controlled trial of a multi-component cognitive behavioral therapy for insomnia program for military veterans with sleep disturbance. This was a single-arm feasibility and pilot study. Participants were United States post-9/11 veterans with service-connected injuries, university students, and had self-reported sleep disturbances. Restoring Effective Sleep Tranquility was a multi-component cognitive behavioral therapy for insomnia intervention consisting of seven sessions of group therapy and eight 1:1 sessions delivered by occupational therapists. Feasibility and pilot indicators were process, resources, management, and scientific, including pre-post-assessments of sleep difficulties, dysfunctional sleep beliefs, participation, and pain interference. Indicators were supportive of feasibility, including reduced sleep difficulties (for example Medical Outcomes Study Sleep Measure [ t  = 3.29, p  = .02]), reduced nightmares: t  = 2.79, p  = .03; fewer dysfunctional sleep beliefs: t  = 3.63, p  = .01, and greater ability to participate in social roles: t  = -2.86, p  = .03, along with trends towards improved satisfaction with participation and reduced pain interference. The Restoring Effective Sleep Tranquility program may reduce sleep difficulties and improve participation in US veterans with service-connected injuries, and evidence indicates a controlled trial would be feasible to deliver.

  8. On the absence of the Efimov effect in spaces of functions of a given symmetry

    International Nuclear Information System (INIS)

    Vugal'ter, S.A.; Zhislin, G.M.

    1981-01-01

    Strict results on the discrete spectrum of Ho three-particle hamiltonians in certain spaces with a Bsup(delta) function of a given symmetry, are formulated. The theorems presented show that in spaces considered with short-acting potentials the Ho . discrete spectrum is finite, i.e. the Efimov effect is impossible. Theorems are proved using the improved techniques on the basis of properties of virtual levels of operators of the energy of the system of two particles in the function spaces [ru

  9. The effect of symmetry on the U L3 NEXAFS of octahedral coordinated uranium(vi)

    Energy Technology Data Exchange (ETDEWEB)

    Bagus, Paul S. [Department of Chemistry, University of North Texas, Denton, Texas 76203-5017, USA; Nelin, Connie J. [Consultant, Austin, Texas 78730, USA; Ilton, Eugene S. [Pacific Northwest National Laboratory, Richland, Washington 99352, USA

    2017-03-21

    We describe a detailed theoretical analysis of how distortions from ideal cubic or Oh symmetry affect the shape, in particular the width, of the U L3-edge NEXAFS for U(VI) in octahedral coordination. The full-width-half-maximum (FWHM) of the L3-edge white line decreases with increasing distortion from Oh symmetry due to the mixing of symmetry broken t2g and eg components of the excited state U(6d) orbitals. The mixing is allowed because of spin-orbit splitting of the ligand field split 6d orbitals. Especially for higher distortions, it is possible to identify a mixing between one of the t2g and one of the eg components, allowed in the double group representation when the spin-orbit interaction is taken into account. This mixing strongly reduces the ligand field splitting, which, in turn, leads to a narrowing of the U L3 white line. However, the effect of this mixing is partially offset by an increase in the covalent anti-bonding character of the highest energy spin-orbit split eg orbital. At higher distortions, mixing overwhelms the increasing anti-bonding character of this orbital which leads to an accelerated decrease in the FWHM with increasing distortion. Additional evidence for the effect of mixing of t2g and eg components is that the FWHM of the white line narrows whether the two axial U-O bond distances shorten or lengthen. Our ab initio theory uses relativistic wavefunctions for cluster models of the structures; empirical or semi-empirical parameters were not used to adjust prediction to experiment. A major advantage is that it provides a transparent approach for determining how the character and extent of the covalent mixing of the relevant U and O orbitals affect the U L3-edge white line.

  10. The effects of restorative care training on caregiver job satisfaction.

    Science.gov (United States)

    Walker, Bonnie L; Harrington, Susan S

    2013-01-01

    The job satisfaction of assisted living facility staff was examined as part of an evaluation study of a restorative care training program. Participants completed a job satisfaction survey at registration (before the training) and again at follow-up 3 months after registration (1 month after the conclusion of the training). Researchers examined the effects of training on job satisfaction. Researchers found a high level of job dissatisfaction at registration. At follow-up, responses were more positive on most of the items suggesting a slight but significant change to a more positive attitude toward their jobs. Improving staff job satisfaction in the assisted living environment is an important goal and needs further investigation. Providing staff with inservice training may be one way to help nurse educators achieve that goal.

  11. Quantum Space-Time Deformed Symmetries Versus Broken Symmetries

    CERN Document Server

    Amelino-Camelia, G

    2002-01-01

    Several recent studies have concerned the faith of classical symmetries in quantum space-time. In particular, it appears likely that quantum (discretized, noncommutative,...) versions of Minkowski space-time would not enjoy the classical Lorentz symmetries. I compare two interesting cases: the case in which the classical symmetries are "broken", i.e. at the quantum level some classical symmetries are lost, and the case in which the classical symmetries are "deformed", i.e. the quantum space-time has as many symmetries as its classical counterpart but the nature of these symmetries is affected by the space-time quantization procedure. While some general features, such as the emergence of deformed dispersion relations, characterize both the symmetry-breaking case and the symmetry-deformation case, the two scenarios are also characterized by sharp differences, even concerning the nature of the new effects predicted. I illustrate this point within an illustrative calculation concerning the role of space-time symm...

  12. Charge independence and charge symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G A [Washington Univ., Seattle, WA (United States). Dept. of Physics; van Oers, W T.H. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Physics; [TRIUMF, Vancouver, BC (Canada)

    1994-09-01

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs.

  13. Charge independence and charge symmetry

    International Nuclear Information System (INIS)

    Miller, G.A.

    1994-09-01

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs

  14. Breaking of electroweak symmetry: origin and effects; Brisure de symetrie electrobaible: origine et consequence

    Energy Technology Data Exchange (ETDEWEB)

    Delaunay, C

    2008-10-15

    The Higgs boson appears as the corner stone of high energy physics, it might be the cause of the excess of matter that led to the formation of the structures of the universe and it seems that it drives the breaking of the electroweak symmetry. Moreover, when the stability at low energies of the Higgs boson is assured by an extra space dimension, it appears that this extra dimension can explain most issues in the flavor physics that are not understood by the standard model. The first chapter presents the main tools of effective field theories, the role of experimental data in the construction of theories valid beyond the standard model is discussed. The second chapter focuses on the electroweak baryogenesis that allows the testing of new physics via the electroweak phase transition. We detail the calculation of a Higgs potential at finite temperature. We follow the dynamics of the phase transition including nucleation an supercooling. Finally we investigate the prospects of gravity wave detection to see the effects of a strong electroweak phase transition. The 2 last chapters are dedicated to the physics of extra-dimension. The properties of the dynamics of scalar, vector fields with a 1/2 spin plunged in a 5 d. Anti de Sitter geometry are reviewed. We present a model of lepton masses and mixings based on the A{sub 4} non-Abelian discrete symmetry. It is shown that this model does not contradict the tests of electroweak precision. (A.C.)

  15. Control of magnonic spectra in cobalt nanohole arrays: the effects of density, symmetry and defects

    International Nuclear Information System (INIS)

    Barman, Anjan

    2010-01-01

    Magnetic nanohole arrays are important systems for propagation of magnetic excitations and are among the potential candidates for magnonic crystals. A thorough investigation of magnonic band structures and the effect of the geometry of the array on them are important. Here, we present a systematic micromagnetic simulation study of magnonic modes in cobalt nanohole (antidot) arrays. In particular, we investigate the effects of the areal density and symmetry of the array and defects introduced in the array. The magnonic modes are strongly dependent on the density and the symmetry of the array but are weakly dependent on the defects. We have further investigated the modes in a tailored array consisting of equally wide hexagonal arrays with varying density. The magnonic spectrum of the tailored array contains additional modes above the modes of the constituent arrays due to the appearance of irregular domain structures at the regions joining arrays of two different types. This opens up the possibility of tuning the magnonic bands in magnetic nanohole arrays by careful design of the structure of the array.

  16. Quark Loop Effects on Dressed Gluon Propagator in Framework of Global Color Symmetry Model

    Institute of Scientific and Technical Information of China (English)

    ZONG Hong-Shi; SUN Wei-Min

    2006-01-01

    Based on the global color symmetry model (GCM), a method for obtaining the quark loop effects on the dressed gluon propagator in GCM is developed. In the chiral limit, it is found that the dressed gluon propagator containing the quark loop effects in the Nambu-Goldstone and Wigner phases are quite different. In solving the quark self-energy functions in the two different phases and subsequent study of bag constant one should use the above dressed gluon propagator as input. The above approach for obtaining the current quark mass effects on the dressed gluon propagator is quite general and can also be used to calculate the chemical potential dependence of the dressed gluon propagator.

  17. Transport properties through graphene grain boundaries: strain effects versus lattice symmetry

    Science.gov (United States)

    Hung Nguyen, V.; Hoang, Trinh X.; Dollfus, P.; Charlier, J.-C.

    2016-06-01

    As most materials available at the macroscopic scale, graphene samples usually appear in a polycrystalline form and thus contain grain boundaries. In the present work, the effect of uniaxial strain on the electronic transport properties through graphene grain boundaries is investigated using atomistic simulations. A systematic picture of transport properties with respect to the strain and lattice symmetry of graphene domains on both sides of the boundary is provided. In particular, it is shown that strain engineering can be used to open a finite transport gap in all graphene systems where the two domains are arranged in different orientations. This gap value is found to depend on the strain magnitude, on the strain direction and on the lattice symmetry of graphene domains. By choosing appropriately the strain direction, a large transport gap of a few hundred meV can be achieved when applying a small strain of only a few percents. For a specific class of graphene grain boundary systems, strain engineering can also be used to reduce the scattering on defects and thus to significantly enhance the conductance. With a large strain-induced gap, these graphene heterostructures are proposed to be promising candidates for highly sensitive strain sensors, flexible electronic devices and p-n junctions with non-linear I-V characteristics.

  18. Mirror Lake contaminanats - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  19. EFFECTS OF STREAM RESTORATION ON DENITRIFICATION In AN URBANIZING WATERSHED

    Science.gov (United States)

    Increased delivery of nitrogen due to urbanization and stream ecosystem degradation is contributing to eutrophication in coastal regions of the eastern United States. We tested whether geomorphic restoration involving hydrologic “reconnection” of a stream to its floodplain could ...

  20. Symmetry witnesses

    Science.gov (United States)

    Aniello, Paolo; Chruściński, Dariusz

    2017-07-01

    A symmetry witness is a suitable subset of the space of selfadjoint trace class operators that allows one to determine whether a linear map is a symmetry transformation, in the sense of Wigner. More precisely, such a set is invariant with respect to an injective densely defined linear operator in the Banach space of selfadjoint trace class operators (if and) only if this operator is a symmetry transformation. According to a linear version of Wigner’s theorem, the set of pure states—the rank-one projections—is a symmetry witness. We show that an analogous result holds for the set of projections with a fixed rank (with some mild constraint on this rank, in the finite-dimensional case). It turns out that this result provides a complete classification of the sets of projections with a fixed rank that are symmetry witnesses. These particular symmetry witnesses are projectable; i.e. reasoning in terms of quantum states, the sets of ‘uniform’ density operators of corresponding fixed rank are symmetry witnesses too.

  1. The effect of slight thinning of managed coniferous forest on landscape appreciation and psychological restoration

    Science.gov (United States)

    Takayama, Norimasa; Saito, Haruo; Fujiwara, Akio; Horiuchi, Masahiro

    2017-12-01

    We investigated the influence of slight thinning (percentage of woods: 16.6%, basal area: 9.3%) on landscape appreciation and the psychological restorative effect of an on-site setting by exposing respondents to an ordinarily managed coniferous woodland. The experiments were conducted in an experimental plot in the same coniferous woodland in May (unthinned) and October 2013 (thinned). The respondents were the same 15 individuals for both experiments. Respondents were individually exposed to the enclosed plot and the forest-view plot within the same tent for 15 min. In both sessions, respondents were required to answer three questionnaires measuring their mood (Profile of Mood States), emotion (Positive and Negative Affect Schedule), and feeling of restoration (Restorative Outcome Scale) to investigate the psychological restorative effect before and after the experiment. They completed two other questionnaires measuring appreciation for the environment (Semantic Differential) and the restorative properties of the environment (Perceived Restorativeness Scale) following the experiments. We first analyzed the difference in landscape appreciation between the unthinned and thinned conditions. We did not find any statistical difference in appreciation for the environment (Semantic Differential) or the restorative properties of the environment (Perceived Restorativeness Scale); rather, we found that weather conditions had a primary influence on landscape appreciation. With respect to the psychological restorative effect, a two-way repeated analysis of valiance (ANOVA) revealed significant main effects for a selection of indices, depending on the presence or absence of thinning. However, multiple comparison analyses revealed that these effects seemed to be due to the difference in the experimental experience rather than the presence or absence of thinning. In conclusion, the effect of the slight thinning of the managed coniferous forest was too weak to be reflected in the

  2. Monitoring effects of river restoration on groundwater with radon

    International Nuclear Information System (INIS)

    Hoehn, Eduard

    2007-01-01

    The restoration of the perialpine river Toess in a floodplain of northern Switzerland (Linsental) included the removal of bank reinforcements and tracer studies in the river and in oberservation wells of the adjacent alluvial groundwater. The river water is continuously recharging the aquifer system and the groundwater is used extensively as drinking water. Radon activity concentrations of freshly infiltrated groundwater are interpreted as radon groundwater age between the river and a well. A first flood after the restoration operations resulted in a widening of the river bed and in a reduction of the flow distance to the wells. Sixteen days after a second flood, the results of radon measurements were compared with those from before the restoration. The radon age of the groundwater between the river and the wells decreased, probably as a result of the reduction of the flow distances. Concentrations of autochthonous and coliform bacteria increased after the restoration operation and even more one day after the first flood. Thus the findings on the bacteria corroborate the interpretation of the radon concentrations. The restoration has not yet reduced the quality of the groundwater, which is pumped for drinking water. The study is contributing to the solution of land-use conflicts between river restoration and the supply of drinking water from the alluvial groundwater. (orig.) [de

  3. Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms

    Directory of Open Access Journals (Sweden)

    Zheng H.

    2016-01-01

    Full Text Available We study the dipole response associated with the Pygmy Dipole Resonance (PDR and the Isovector Giant Dipole Resonance (IVGDR, in connection with specific properties of the nuclear effective interaction (symmetry energy and momentum dependence, in the neutron-rich systems 68Ni, 132Sn and 208Pb. We perform our investigation within a microscopic transport model based on the Landau-Vlasov kinetic equation.We observe that the peak energies of PDR and IVGDR are shifted to higher values when employing momentum dependent interactions, with respect to the results obtained neglecting momentum dependence. The calculated energies are close to the experimental values and similar to the results obtained in Hartree-Fock (HF with Random Phase Approximation (RPA calculations.

  4. Observation of resonant symmetry lifting by an effective bias field in a parametrically modulated atomic trap

    International Nuclear Information System (INIS)

    Kim, Yonghee; Heo, Myoung-Sun; Moon, Geol; Kim, Ji-Hyoun; Jhe, Wonho; Noh, Heung-Ryoul

    2010-01-01

    We experimentally demonstrate resonant symmetry lifting in a parametrically modulated magneto-optical trap of cold 85 Rb atoms. This is achieved by applying a weak additional modulation at half the frequency of the strong parametric modulation, which acts as an effective static bias field to the system. We measure the system response by varying the amplitude of the additional fictitious bias as well as the relative phase between the bias and the parametric drive, and the results are in good agreement with theory. The additional modulation provides an additional degree of freedom to control the system, which is useful for investigating system properties such as susceptibility, dynamic response, and related critical phenomena. We also have measured the amplitude of the response to higher harmonics of the additional modulation frequency, which allows more precise understanding of the system dynamics.

  5. The role of symmetry in the mass independent isotope effect in ozone

    Science.gov (United States)

    Michalski, Greg; Bhattacharya, S. K.

    2009-01-01

    Understanding the internal distribution of “anomalous” isotope enrichments has important implications for validating theoretical postulates on the origin of these enrichments in molecules such as ozone and for understanding the transfer of these enrichments to other compounds in the atmosphere via mass transfer. Here, we present an approach, using the reaction NO2− + O3, for assessing the internal distribution of the Δ17O anomaly and the δ18O enrichment in ozone produced by electric discharge. The Δ17O results strongly support the symmetry mechanism for generating mass independent fractionations, and the δ18O results are consistent with published data. Positional Δ17O and δ18O enrichments in ozone can now be more effectively used in photochemical models that use mass balance oxygen atom transfer mechanisms to infer atmospheric oxidation chemistry. PMID:19307571

  6. Effective chiral restoration in the ρ' meson in lattice QCD

    International Nuclear Information System (INIS)

    Glozman, L. Ya.; Lang, C. B.; Limmer, Markus

    2010-01-01

    In simulations with dynamical quarks it has been established that the ground state ρ in the infrared is a strong mixture of the two chiral representations (0,1)+(1,0) and (1/2,1/2) b . Its angular momentum content is approximately the 3 S 1 partial wave. Effective chiral restoration in an excited ρ-meson would require that in the infrared this meson couples predominantly to one of the two representations. The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the nonperturbatively determined excited state at different resolution scales. We present results for the first excited state of the ρ-meson using simulations with n f =2 dynamical quarks. We point out, that in the infrared a leading contribution to ρ ' =ρ(1450) comes from (1/2,1/2) b , in contrast to the ρ. The ρ ' wave function contains a significant contribution of the 3 D 1 wave which is not consistent with the quark model prediction.

  7. Effective chiral restoration in the ρ' meson in lattice QCD

    Science.gov (United States)

    Glozman, L. Ya.; Lang, C. B.; Limmer, Markus

    2010-11-01

    In simulations with dynamical quarks it has been established that the ground state ρ in the infrared is a strong mixture of the two chiral representations (0,1)+(1,0) and (1/2,1/2)b. Its angular momentum content is approximately the S13 partial wave. Effective chiral restoration in an excited ρ-meson would require that in the infrared this meson couples predominantly to one of the two representations. The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the nonperturbatively determined excited state at different resolution scales. We present results for the first excited state of the ρ-meson using simulations with nf=2 dynamical quarks. We point out, that in the infrared a leading contribution to ρ'=ρ(1450) comes from (1/2,1/2)b, in contrast to the ρ. The ρ' wave function contains a significant contribution of the D13 wave which is not consistent with the quark model prediction.

  8. REVIEWS OF TOPICAL PROBLEMS: Broken symmetry and magnetoacoustic effects in ferroand antiferromagnetics

    Science.gov (United States)

    Turov, Evgenii A.; Shavrov, Vladimir G.

    1983-07-01

    This review of some aspects of the magnetoacoustics of ferro- and antiferromagnetic materials has been written in connection with the 25th anniversary of the rise of this field of physics of magnetic phenomena. Primary attention is paid to relatively new problems that have not been reflected in the existing monographs and reviews. The topic is a group of linear magnetoacoustic effects that manifest spontaneous symmetry breaking caused by magnetic ordering in a system of two coupled fields: the magnetization field M (r) and the deformation field uij(r). To some extent these effects are analogous to the Higgs effect in the theory of elementary particles (the Higgs mechanism of the origin of the mass of a particle) or the Meissner effect in the theory of superconductivity. A direct analog of the stated effects is the so-called magnetoelastic gap in the magnon spectrum, while an analog of an accompanying effect is the softening of the quasiacoustic modes interacting with it (up to the vanishing of the corresponding dynamic elastic moduli). However, a characteristic feature of such effects in crystalline (anisotropic) magnetic materials is that they are manifested mainly near points of magnetic (spin-reorientation) phase transitions. This review treats the coupled magnetoelastic waves in ferro- and antiferromagnetic materials of different types that show phase transitions with respect to temperature, magnetic field, or pressure.

  9. Mirror symmetry

    CERN Document Server

    Voisin, Claire

    1999-01-01

    This is the English translation of Professor Voisin's book reflecting the discovery of the mirror symmetry phenomenon. The first chapter is devoted to the geometry of Calabi-Yau manifolds, and the second describes, as motivation, the ideas from quantum field theory that led to the discovery of mirror symmetry. The other chapters deal with more specialized aspects of the subject: the work of Candelas, de la Ossa, Greene, and Parkes, based on the fact that under the mirror symmetry hypothesis, the variation of Hodge structure of a Calabi-Yau threefold determines the Gromov-Witten invariants of its mirror; Batyrev's construction, which exhibits the mirror symmetry phenomenon between hypersurfaces of toric Fano varieties, after a combinatorial classification of the latter; the mathematical construction of the Gromov-Witten potential, and the proof of its crucial property (that it satisfies the WDVV equation), which makes it possible to construct a flat connection underlying a variation of Hodge structure in the ...

  10. The effects of dication symmetry on ionic liquid electrolytes in supercapacitors

    Science.gov (United States)

    Li, Song; Zhu, Mengyang; Feng, Guang

    2016-11-01

    The effects of dication symmetry on the structure and capacitance of the electrical double layers (EDLs) of dicationic ionic liquids (DILs) near graphene electrodes were investigated by molecular dynamics (MD) simulation in this work. Symmetrical 1-hexyl-3-dimethylimidazolium di[bis(trifluoromethyl)imide]([C6(mim)2](Tf2N)2) and asymmetrical 1-(1-trimethylammonium-yl-hexyl)-3-methylimidazolium di[bis(trifluoro-methanesulfonyl)-imide] ([C6(tma)(mim)](Tf2N)2) were both employed. Radial distribution function (RDF) analysis of the two DILs revealed a shorter distance between the cation-anion pairs in symmetrical [C6(mim)2](Tf2N)2), which was attributed to the closely packed imidazolium ring-anion pairs. In contrast, the trimethylammonium head groups and anions exhibit a relatively longer distance, but a stronger correlation in asymmetrical [C6(tma)(mim)](Tf2N)2. In addition, it was illustrated that more symmetrical DIL ions in EDLs are distributed near graphite electrodes and exhibit closer distances to the electrode, which is most probably due to the parallel orientation of imidazolium rings, reducing the distance between the cation and the graphene. In contrast, asymmetrical DILs, with one trimethylammonium head group and one imidazolium ring in the dications, are loosely packed due to their tilting orientation near graphene surfaces. However, the capacitance-potential (C-V) curves of the two DILs are almost the same, regardless of the opposite sign of potential of zero charge (PZC), indicating the insignificant influence of dication symmetry on the capacitance of DIL-based supercapacitors.

  11. Interfacial symmetry of Co–Alq_3–Co hybrid structures for effective spin filtering

    International Nuclear Information System (INIS)

    Lam, Tu-Ngoc; Lai, Yu-Ling; Chen, Chih-Han; Chen, Po-Hung; Wei, Der-Hsin; Lin, Hong-Ji; Chen, C.T.; Sheu, Jeng-Tzong; Hsu, Yao-Jane

    2015-01-01

    Graphical abstract: - Highlights: • The spin interface at Alq_3/Co and Co/Alq_3 contacts was examined. • An interfacial symmetry was determined at Co–Alq_3–Co interfaces. • Spin-polarized N orbitals are induced within the Co atop Alq_3 hybridized interface. • The spin-filter role at the top contact interface of Alq_3/Co is proved. • Effective spin-filtering at Co–Alq_3–Co contacts was elucidated. - Abstract: Understanding the interfacial behavior at FM-OSC-FM hybrid structures for both the bottom contact (Alq_3 adsorption on Co, Co/Alq_3) and the top contact (Co atop Alq_3, Alq_3/Co) is crucial for efficient spin filtering with transport of spin-polarized charge carriers through these interfaces. X-ray photoelectron spectroscopy (XPS) spectra indicate a symmetry of charge transfer from Co to Alq_3 and the corresponding orbital hybridization to a certain extent at both contacts. The alignment of energy levels at both Alq_3/Co and Co/Alq_3 heterostructures is depicted with ultraviolet photoelectron spectroscopy (UPS). Through magnetic images acquired with a X-ray photoemission electron microscope (XPEEM), the strong hybridization of the top contact presents no micromagnetic domain but still shows magnetic coupling, to some extent, to the bottom contact in the Co–Alq_3–Co trilayer structure. Measurements of X-ray magnetic circular dichroism (XMCD) demonstrate the induced spin-polarization of non-magnetic Alq_3 at both contacts, proving Alq_3 a unique and promising organic material for spin filtering in OSV.

  12. The Effect of Retardation on the Spontaneous Breaking of Chiral Symmetry in GCM

    Institute of Scientific and Technical Information of China (English)

    YANG Sheng-Dong; ZHAI Chen-Yang; ZHOU Zhi-Ning; YANG Ze-Sen

    2001-01-01

    An effective Hamiltonian including current-current coupling from the global color symmetry model is -R2 2derived.Retardation effects are introduced by the factor ( R/ ) e ,instead of δ (r) in the correlation kernel,from which the retardation gap equation with α-α coupling in the 3po vacuum is obtained,qq condensations of different retardation parameters R with or without the α-α term are calculated.The results show the effects of retardation,and indicate that the typical value of R is about 2 fm-1 at reasonable value of qq condensation.And while taking typical value 1 fm-1 of R,the condensation 1/3 is about 13% larger than that with no retardation effect.With the α-αterms,the condensation (qq) 1/3 is about 17%o larger than that without it for all values of the parameter R.This shows that the retardation effects and the α-α terms are important for further studying in the Iow-energy region.``

  13. Coleman-Weinberg symmetry breaking in an anisotropic spacetime

    International Nuclear Information System (INIS)

    Futamase, T.

    1984-01-01

    The Coleman-Weinberg mechanism of symmetry breaking in a Bianchi type-I universe is investigated. The one-loop effective potential for a phi 4 theory and for scalar electrodynamics is calculated by the zeta-function method. The result indicates that the symmetry of the theory will be restored in the highly anisotropic, cold, early universe, irrespective of the coupling between the scalar field and the spacetime curvature scalar. This mechanism of the phase transition explains the isotropy of our universe

  14. The effectiveness of different polymerization protocols for class II composite resin restorations.

    NARCIS (Netherlands)

    Jong, L.C.G. de; Opdam, N.J.M.; Bronkhorst, E.M.; Roeters, F.J.M.; Wolke, J.G.C.; Geitenbeek, B.

    2007-01-01

    OBJECTIVES: To investigate the effect of reduced light exposure times on Vickers hardness (VH) of class II composite resin restorations. METHODS: Class II restorations were made in vitro in three 2mm thick increments in a human molar. Two composite resins (Clearfil AP-X; Esthet-X) were polymerized

  15. Effect of a retention groove on the shear bond strength of dentin-bonded restorations

    NARCIS (Netherlands)

    de Kok, P.; de Jager, N.; Veerman, I.A.M.; Hafeez, N.; Kleverlaan, C.J.; Roeters, J.F.M.

    2016-01-01

    Statement of problem. With the increasing use of minimally invasive restorations, effective adhesion becomes more important. Applying mechanical retention to a flat dentin surface might improve the adhesion of ceramic and composite resin restorations. Purpose. The purpose of this in vitro study was

  16. Effect of mangrove restoration on crab burrow density in Luoyangjiang Estuary, China

    Directory of Open Access Journals (Sweden)

    Wei Li

    2015-07-01

    Full Text Available Background Mangrove restoration seeks to restore or rebuild degraded mangrove systems. The methods of mangrove restoration include ecological projects and restoration-oriented technologies, the latter of which are designed to restore the structure, processes as well as related physical, chemical and biological characteristics of wetlands and to ensure the provision of ecosystem services. As important components of mangrove ecosystem, benthic organisms and crabs play a key role in nutrient cycling. In addition, mangrove restoration, such as vegetation restoration measures, can lead to changes in the benthic faunal communities. This study investigates whether the presence of different mangrove species, age and canopy cover of mangrove communities affect the density of crab burrows. Methods The Luoyangjiang Estuary, in the southeast of Fujian Province, was selected as our research area. A survey, covering 14 sites, was conducted to investigate the impacts of mangrove restoration on the density of crab burrows in four rehabilitated forests with different stand ages and canopy. Results It was found that differences in vegetation types had a large impact on crab density and that the density of crab burrows was lower on exposed beaches (non-mangrove than under mature Kandelia candel, Aegiceras corniculatum and Avicennia marina communities. In general, the amount of leaf litter and debris on mangrove mudflats was greater than on the beaches as food sources for crabs. Two-factor analysis of variance (ANOVA shows that changes in mangrove species and age since restoration had different effects on crab burrow density. The effect of canopy cover was highly significant on crab burrow density. Conclusions The results suggest that in the process of mangrove restoration the combined effects of mangrove stand age, canopy cover and other factors should be taken into account. This study further supports the findings of the future scientific research and practice on

  17. Sequential flavor symmetry breaking

    International Nuclear Information System (INIS)

    Feldmann, Thorsten; Jung, Martin; Mannel, Thomas

    2009-01-01

    The gauge sector of the standard model exhibits a flavor symmetry that allows for independent unitary transformations of the fermion multiplets. In the standard model the flavor symmetry is broken by the Yukawa couplings to the Higgs boson, and the resulting fermion masses and mixing angles show a pronounced hierarchy. In this work we connect the observed hierarchy to a sequence of intermediate effective theories, where the flavor symmetries are broken in a stepwise fashion by vacuum expectation values of suitably constructed spurion fields. We identify the possible scenarios in the quark sector and discuss some implications of this approach.

  18. Sequential flavor symmetry breaking

    Science.gov (United States)

    Feldmann, Thorsten; Jung, Martin; Mannel, Thomas

    2009-08-01

    The gauge sector of the standard model exhibits a flavor symmetry that allows for independent unitary transformations of the fermion multiplets. In the standard model the flavor symmetry is broken by the Yukawa couplings to the Higgs boson, and the resulting fermion masses and mixing angles show a pronounced hierarchy. In this work we connect the observed hierarchy to a sequence of intermediate effective theories, where the flavor symmetries are broken in a stepwise fashion by vacuum expectation values of suitably constructed spurion fields. We identify the possible scenarios in the quark sector and discuss some implications of this approach.

  19. The effect of retributive and restorative sentencing on psychological effects of criminal proceedings.

    Science.gov (United States)

    Laxminarayan, Malini

    2013-03-01

    Retribution and restoration have been cited as two goals of sentencing for victims. Furthermore, there is a perspective that acknowledges the overlap of these two aims, seeking to obtain restoration through retribution. Achieving these goals may have implications for the victim's psychological well-being. The current study examines 101 victims of serious crime and how different outcomes may impact their perceptions of psychological well-being. Incarceration, community service, compensation from the offender, and compensation from the state, in addition to acquittals, are included as predictors of the dependent variable. After reviewing the literature on retributive and restorative sentencing, also making a distinction between compensation from the offender and compensation from the state, hierarchical regression analysis finds that compensation from the offender is the only sentencing option significantly associated with psychological effects.

  20. Political and Economic Geomorphology: The Effect of Market Forces on Stream Restoration Designs

    Science.gov (United States)

    Singh, J.; Doyle, M. W.; Lave, R.; Robertson, M.

    2013-12-01

    Stream restoration in the U.S. is increasingly driven by compensatory mitigation; impacts to streams associated with typical land development activities must be offset via restoration of streams elsewhere. This policy application creates conditions in which restored stream ';credits' are traded under market-like conditions, comparable to wetland mitigation, carbon offsets, or endangered species habitat banking. The effect of this relatively new mechanism to finance stream restoration on design and construction is unknown. This research explores whether the introduction of a credit-based mitigation apparatus results in streams designed to maximize credit yields (i.e., ';credit-chasing') rather than focusing on restoring natural systems or functions. In other words, are market-based restored streams different from those designed for non-market purposes? We quantified geomorphic characteristics (e.g. hydraulic geometry, sinuosity, profile, bed sediment, LWD) of three types of streams: (1) a random sample of non-restored reaches, (2) streams restored for compensatory mitigation, and (3) streams restored under alternative funding sources (e.g., government grant programs, non-profit activities). We also compared the location of the types of stream reaches to determine whether there is a spatiality of restored streams. Physical data were complemented with a series of semi-structured interviews with key personnel in the stream restoration industry to solicit information on the influence of policy interpretation and market-driven factors on the design process. Preliminary analysis suggests that restoration is driving a directional shift in stream morphology in North Carolina. As a simple example, in the Piedmont, non-restored and restored channels had mean sinuosity of 1.17 and 1.23, respectively (p sale of restored stream credits, was seen as critically important rather than the marginal gains to be made by manipulating particular stream designs to glean more credits

  1. Morphodynamic effects of riparian vegetation growth after stream restoration

    NARCIS (Netherlands)

    Vargas-Luna, Andrés; Crosato, Alessandra; Anders, Niels; Hoitink, Antonius J.F.; Keesstra, Saskia D.; Uijttewaal, Wim S.J.

    2018-01-01

    The prediction of the morphological evolution of renaturalized streams is important for the success of restoration projects. Riparian vegetation is a key component of the riverine landscape and is therefore essential for the natural rehabilitation of rivers. This complicates the design of

  2. Superconducting Gap Symmetry of LaFeP(O,F Observed by Impurity Doping Effect

    Directory of Open Access Journals (Sweden)

    Shigeki Miyasaka

    2016-08-01

    Full Text Available We have investigated Mn, Co and Ni substitution effects on polycrystalline samples of LaFePO0.95F0.05 by resistivity and magnetoresistance measurements. In LaFe1-xMxPO0.95F0.05 (M = Mn, Co and Ni, the superconducting transition temperature (Tc monotonously decreases with increasing the impurity doping level of x. There is a clear difference of Tc suppression rates among Mn, Co and Ni doping cases, and the decreasing rate of Tc by Mn doping as a magnetic impurity is larger than those by the nonmagnetic doping impurities (Co/Ni. This result indicates that in LaFePO0.95F0.05, Tc is rapidly suppressed by the pair-breaking effect of magnetic impurities, and the pairing symmetry is a full-gapped s-wave. In the nonmagnetic impurity-doped systems, the residual resistivity in the normal state has nearly the same value when Tc becomes zero. The residual resistivity value is almost consistent with the universal value of sheet resistance for two-dimensional superconductors, suggesting that Tc is suppressed by electron localization in Co/Ni-doped LaFePO0.95F0.05.

  3. Symmetry rules. How science and nature are founded on symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, J.

    2008-07-01

    When we use science to describe and understand the world around us, we are in essence grasping nature through symmetry. In fact, modern theoretical physics suggests that symmetry is a, if not the, foundational principle of nature. Emphasizing the concepts, this book leads the reader coherently and comprehensively into the fertile field of symmetry and its applications. Among the most important applications considered are the fundamental forces of nature and the Universe. It is shown that the Universe cannot possess exact symmetry, which is a principle of fundamental significance. Curie's principle - which states that the symmetry of the effect is at least that of the cause - features prominently. An introduction to group theory, the mathematical language of symmetry, is included. This book will convince all interested readers of the importance of symmetry in science. Furthermore, it will serve as valuable background reading for all students in the physical sciences. (orig.)

  4. Symmetry rules How science and nature are founded on symmetry

    CERN Document Server

    Rosen, Joe

    2008-01-01

    When we use science to describe and understand the world around us, we are in essence grasping nature through symmetry. In fact, modern theoretical physics suggests that symmetry is a, if not the, foundational principle of nature. Emphasizing the concepts, this book leads the reader coherently and comprehensively into the fertile field of symmetry and its applications. Among the most important applications considered are the fundamental forces of nature and the Universe. It is shown that the Universe cannot possess exact symmetry, which is a principle of fundamental significance. Curie's principle - which states that the symmetry of the effect is at least that of the cause - features prominently. An introduction to group theory, the mathematical language of symmetry, is included. This book will convince all interested readers of the importance of symmetry in science. Furthermore, it will serve as valuable background reading for all students in the physical sciences.

  5. The effect of urban growth on landscape-scale restoration for a fire-dependent songbird

    Science.gov (United States)

    Pickens, Bradley A.; Marcus, Jeffrey F.; Carpenter, John P.; Anderson, Scott; Taillie, Paul J.; Collazo, Jaime A.

    2017-01-01

    A landscape-scale perspective on restoration ecology has been advocated, but few studies have informed restoration with landscape metrics or addressed broad-scale threats. Threats such as urban growth may affect restoration effectiveness in a landscape context. Here, we studied longleaf pine savanna in the rapidly urbanizing southeastern United States where a habitat-specialist bird, Bachman's sparrow (Peucaea aestivalis), is closely associated with savanna vegetation structure and frequent fire. Our objectives were to construct a species distribution model for Bachman's sparrow, determine the relationship between fire and urbanization, quantify the urban growth effect (2010–2090), identify potential restoration areas, and determine the interaction between restoration potential and urban growth by 2050. Number of patches, patch size, and isolation metrics were used to evaluate scenarios. The species distribution model was 88% accurate and emphasized multiscale canopy cover characteristics, fire, and percent habitat. Fires were less common urban areas, and this fire suppression effect exacerbated urban growth effects. For restoration scenarios, canopy cover reduction by 30% resulted in nearly double the amount of habitat compared to the prescribed fire scenario; canopy cover reduction resulted in larger patch sizes and less patch isolation compared to current conditions. The effect of urban growth on restoration scenarios was unequal. Seventy-four percent of restoration areas from the prescribed fire scenario overlapped with projected urban growth, whereas the canopy cover reduction scenario only overlapped by 9%. We emphasize the benefits of simultaneously considering the effects of urban growth and landscape-scale restoration potential to promote a landscape with greater patch sizes and less isolation.

  6. Gauge symmetry from decoupling

    Directory of Open Access Journals (Sweden)

    C. Wetterich

    2017-02-01

    Full Text Available Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang–Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.

  7. Dynamical symmetries for fermions

    International Nuclear Information System (INIS)

    Guidry, M.

    1989-01-01

    An introduction is given to the Fermion Dynamical Symmetry Model (FDSM). The analytical symmetry limits of the model are then applied to the calculation of physical quantities such as ground-state masses and B(E 2 ) values in heavy nuclei. These comparisons with data provide strong support for a new principle of collective motion, the Dynamical Pauli Effect, and suggest that dynamical symmetries which properly account for the pauli principle are much more persistent in nuclear structure than the corresponding boson symmetries. Finally, we present an assessment of criticisms which have been voiced concerning the FDSM, and a discussion of new phenomena and ''exotic spectroscopy'' which may be suggested by the model. 14 refs., 8 figs., 4 tabs

  8. Respiratory health effects associated with restoration work in post-Hurricane Katrina New Orleans.

    Science.gov (United States)

    Rando, Roy J; Lefante, John J; Freyder, Laurie M; Jones, Robert N

    2012-01-01

    This study examines prevalence of respiratory conditions in New Orleans-area restoration workers after Hurricane Katrina. Between 2007 and 2010, spirometry and respiratory health and occupational questionnaire were administered to 791 New Orleans-area adults who mostly worked in the building construction and maintenance trades or custodial services. The associations between restoration work hours and lung function and prevalence of respiratory symptoms were examined by multiple linear regression, χ², or multiple logistic regression. 74% of participants performed post-Katrina restoration work (median time: 620 hours). Symptoms reported include episodes of transient fever/cough (29%), sinus symptoms (48%), pneumonia (3.7%), and new onset asthma (4.5%). Prevalence rate ratios for post-Katrina sinus symptoms (PRR = 1.3; CI: 1.1, 1.7) and fever and cough (PRR = 1.7; CI: 1.3, 2.4) were significantly elevated overall for those who did restoration work and prevalence increased with restoration work hours. Prevalence rate ratios with restoration work were also elevated for new onset asthma (PRR = 2.2; CI: 0.8, 6.2) and pneumonia (PRR = 1.3; CI: 0.5, 3.2) but were not statistically significant. Overall, lung function was slightly depressed but was not significantly different between those with and without restoration work exposure. Post-Katrina restoration work is associated with moderate adverse effects on respiratory health, including sinusitis and toxic pneumonitis.

  9. Central and peripheral effects of chronic food restriction and weight restoration in the rat.

    Science.gov (United States)

    Kinzig, Kimberly P; Hargrave, Sara L; Tao, Erin E

    2009-02-01

    Previous studies have demonstrated that some endocrine consequences of long-term caloric restriction persist after weight restoration in human subjects. Here we evaluate effects of chronic food restriction in rats that were restricted to 70% of control kcal for 4 wk and subsequently weight restored. Measures were taken from rats at 80% (chronically restricted; CR), 90% (partially weight restored; PR), 100% (fully weight restored; FR), and after 4 wk at 100% body weight of controls (extended weight restored; ER). Plasma insulin and leptin were decreased, and ghrelin was increased in CR compared with controls. Leptin and ghrelin normalized with weight restoration at PR, FR, and ER; however, baseline insulin was not normalized until the ER state. Hypothalamic mRNA expression levels for proopiomelanocortin (POMC), agouti-related protein (AgRP), and neuropeptide Y (NPY) revealed significantly less POMC mRNA expression in CR and PR rats, and significantly less arcuate NPY mRNA in PR and FR. In the dorsomedial hypothalamus, CR, PR, and FR rats had significantly increased NPY expression that was not normalized until the ER state. In response to a test meal, insulin and ghrelin release patterns were altered through the FR stage, and ghrelin remained affected at ER. Collectively, these data demonstrate that mere weight restoration is not sufficient to normalize hypothalamic gene expression levels and endocrine responses to a meal, and that meal-related ghrelin responses persist despite weight restoration for up to 4 wk.

  10. Effects of oral hygiene, residual caries and cervical Marginal-gaps on the survival of proximal atraumatic restorative treatment approach restorations

    Directory of Open Access Journals (Sweden)

    Arthur M Kemoli

    2011-01-01

    Full Text Available Background: Although Atraumatic restorative treatment (ART approach has been in existence for a while, the reasons for the poor performance of multisurface ART restorations are not very clear. Aim: The aim of this study is to investigate the effects of oral hygiene, residual caries and cervical marginal-gaps on survival of proximal ART restorations. Settings: Two rural divisions in Kenya were selected for the study. Design: A randomized clinical trial. Material and Methods: The 804 children in the study had their baseline- and 2-year dental plaque levels documented. Each child received one proximal restoration in a primary molar using ART approach, together with trained and pre-tested operators/assistants, three glass ionomer cements (GIC-brands and two tooth-isolation methods. The restorations were clinically evaluated soon after placement and after 2 years. Post-restorative bite-wing radiographs taken soon after restoration were also evaluated. Statistical analysis: Statistical Package for Social Sciences (SPSS version 14 computer programme was used and results tested using Pearson′s correlation, Cox Proportional Hazards regression analysis and Multiple Logistic regression models tests. Results: At baseline and after 2 years, the mean cumulative survival and plaque index changed from 94.4% to 30.8% and 2.34 (Standard Deviation, or SD of 0.46 to 1.92 (SD 2.1 respectively, with higher plaque indices associated with higher restoration failures. Of the 507 radiographs evaluated, 48 (9.5%, 63 (12.4% and 9 (1.8% restorations had residual caries (RC, cervical marginal-gaps (CMG and both RC/CMG respectively. Survival of the restorations with RC/CMG was significantly lower (p = 0.003 compared to those with RC or without RC. Conclusion: Low survival of proximal restorations in the study was associated with the presence of cervical marginal-gaps.

  11. Lubricating and Waxy Esters. VI. Effect of Symmetry about Ester on Crystallization of Linear Monoester Isomers

    Directory of Open Access Journals (Sweden)

    Laziz Bouzidi

    2014-08-01

    Full Text Available The crystal structure development of jojoba-like esters incorporating either 1-decenoic acid and/or 1-decenol, namely octadec-9-enyl dec-9-enoate (JLE-281, and its isomer dec-9-enyl oleate (JLE-282 was investigated to reveal the effect of symmetry about the ester group on crystallization of aliphatic fatty monoesters. The phase transformation path was investigated with temperature-time resolved X-ray diffraction during stepped isothermal crystallization, and while cooling from the melt at a fixed rate. Startling differences in phase behavior were uncovered between the isomers. When stepped isothermals were used, selective extinctions occurred at a transition temperature for JLE-281 but not for JLE-282. The extinctions, which are due to dramatic changes in the electronic density of certain families of planes, indicate a phase transition attributed to a brusque rearrangement of the oxygen atoms in the crystal subcell. The phase transition did not occur when the JLEs were cooled continuously. The crucial role played by the position of the alkyl chain and its orientation relative to the easy rotation site of the C–O bond in the phase trajectories of the JLEs was particularly highlighted.

  12. Phenotypic plasticity and effects of selection on cell division symmetry in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Uttara N Lele

    Full Text Available Aging has been demonstrated in unicellular organisms and is presumably due to asymmetric distribution of damaged proteins and other components during cell division. Whether the asymmetry-induced aging is inevitable or an adaptive and adaptable response is debated. Although asymmetric division leads to aging and death of some cells, it increases the effective growth rate of the population as shown by theoretical and empirical studies. Mathematical models predict on the other hand, that if the cells divide symmetrically, cellular aging may be delayed or absent, growth rate will be reduced but growth yield will increase at optimum repair rates. Therefore in nutritionally dilute (oligotrophic environments, where growth yield may be more critical for survival, symmetric division may get selected. These predictions have not been empirically tested so far. We report here that Escherichia coli grown in oligotrophic environments had greater morphological and functional symmetry in cell division. Both phenotypic plasticity and genetic selection appeared to shape cell division time asymmetry but plasticity was lost on prolonged selection. Lineages selected on high nutrient concentration showed greater frequency of presumably old or dead cells. Further, there was a negative correlation between cell division time asymmetry and growth yield but there was no significant correlation between asymmetry and growth rate. The results suggest that cellular aging driven by asymmetric division may not be hardwired but shows substantial plasticity as well as evolvability in response to the nutritional environment.

  13. Determining the Effectiveness of Aquatic Ecosystem Restoration, Conservation, and Management Practices.

    Science.gov (United States)

    The science of aquatic ecosystem restoration and management is still in its infancy, largely because most projects are inadequately tracked and monitored for assessing their success. Historically, evaluating the effectiveness of best management practices (BMPs) has relied heavily...

  14. Management Effectiveness of a Secondary Coniferous Forest for Landscape Appreciation and Psychological Restoration.

    Science.gov (United States)

    Takayama, Norimasa; Fujiwara, Akio; Saito, Haruo; Horiuchi, Masahiro

    2017-07-18

    We investigated the influence of forest management on landscape appreciation and psychological restoration in on-site settings by exposing respondents to an unmanaged, dense coniferous (crowding) forest and a managed (thinned) coniferous forest; we set the two experimental settings in the forests of the Fuji Iyashinomoroi Woodland Study Center. The respondents were individually exposed to both settings while sitting for 15 min and were required to answer three questionnaires to analyze the psychological restorative effects before and after the experiment (feeling (the Profile of Mood States), affect (the Positive and Negative Affect Schedule), and subjective restorativeness (the Restorative Outcome Scale). To compare landscape appreciation, they were required to answer another two questionnaires only after the experiment, for scene appreciation (the semantic differential scale) and for the restorative properties of each environment (the Perceived Restorativeness Scale). Finally, we obtained these findings: (1) the respondents evaluated each forest environment highly differently and evaluated the thinned forest setting more positively; (2) the respondents' impressions of the two physical environments did not appear to be accurately reflected in their evaluations; (3) forest environments have potential restorative effects whether or not they are managed, but these effects can be partially enhanced by managing the forests.

  15. Symmetry consideration in zero loop-area Sagnac interferometry at oblique incidence for detecting magneto-optic Kerr effects.

    Science.gov (United States)

    Zhu, X D

    2017-08-01

    I present a detailed account of a zero loop-area Sagnac interferometer operated at oblique incidence for detecting magneto-optic Kerr effects arising from a magnetized sample. In particular, I describe the symmetry consideration and various optical arrangements available to such an interferometer that enables measurements of magneto-optic effects due to both in-plane and out-of-plane magnetization of the sample with optimizable signal-to-noise ratios.

  16. Effects of river restoration on riparian biodiversity in secondary channels of the Pite River, Sweden.

    Science.gov (United States)

    Helfield, James M; Engström, Johanna; Michel, James T; Nilsson, Christer; Jansson, Roland

    2012-01-01

    Between 1850 and 1970, rivers throughout Sweden were channelized to facilitate timber floating. Floatway structures were installed to streamline banks and disconnect flow to secondary channels, resulting in simplified channel morphologies and more homogenous flow regimes. In recent years, local authorities have begun to restore channelized rivers. In this study, we examined the effects of restoration on riparian plant communities at previously disconnected secondary channels of the Pite River. We detected no increase in riparian diversity at restored sites relative to unrestored (i.e., disconnected) sites, but we did observe significant differences in species composition of both vascular plant and bryophyte communities. Disconnected sites featured greater zonation, with mesic-hydric floodplain species represented in plots closest to the stream and mesic-xeric upland species represented in plots farthest from the stream. In contrast, restored sites were most strongly represented by upland species at all distances relative to the stream. These patterns likely result from the increased water levels in reconnected channels where, prior to restoration, upland plants had expanded toward the stream. Nonetheless, the restored fluvial regime has not brought about the development of characteristic flood-adapted plant communities, probably due to the short time interval (ca. 5 years) since restoration. Previous studies have demonstrated relatively quick responses to similar restoration in single-channel tributaries, but secondary channels may respond differently due to the more buffered hydrologic regimes typically seen in anabranching systems. These findings illustrate how restoration outcomes can vary according to hydrologic, climatic and ecological factors, reinforcing the need for site-specific restoration strategies.

  17. Combining symmetry collective states with coupled-cluster theory: Lessons from the Agassi model Hamiltonian

    Science.gov (United States)

    Hermes, Matthew R.; Dukelsky, Jorge; Scuseria, Gustavo E.

    2017-06-01

    The failures of single-reference coupled-cluster theory for strongly correlated many-body systems is flagged at the mean-field level by the spontaneous breaking of one or more physical symmetries of the Hamiltonian. Restoring the symmetry of the mean-field determinant by projection reveals that coupled-cluster theory fails because it factorizes high-order excitation amplitudes incorrectly. However, symmetry-projected mean-field wave functions do not account sufficiently for dynamic (or weak) correlation. Here we pursue a merger of symmetry projection and coupled-cluster theory, following previous work along these lines that utilized the simple Lipkin model system as a test bed [J. Chem. Phys. 146, 054110 (2017), 10.1063/1.4974989]. We generalize the concept of a symmetry-projected mean-field wave function to the concept of a symmetry projected state, in which the factorization of high-order excitation amplitudes in terms of low-order ones is guided by symmetry projection and is not exponential, and combine them with coupled-cluster theory in order to model the ground state of the Agassi Hamiltonian. This model has two separate channels of correlation and two separate physical symmetries which are broken under strong correlation. We show how the combination of symmetry collective states and coupled-cluster theory is effective in obtaining correlation energies and order parameters of the Agassi model throughout its phase diagram.

  18. Technique to achieve the symmetry of the new inframammary fold

    Science.gov (United States)

    Pozzi, Marcello; Zoccali, Giovanni; Buccheri, Ernesto Maria; de Vita, Roy

    2014-01-01

    Summary The literature outlines several surgical techniques to restore inframmammary fold definition, but symmetry of the fold is often left to irreproducible procedures. We report our personal technique to restore the symmetry of the inframmammary fold during multistep breast reconstruction. PMID:25078934

  19. Cost-effectiveness of dryland forest restoration evaluated by spatial analysis of ecosystem services

    Science.gov (United States)

    Birch, Jennifer C.; Newton, Adrian C.; Aquino, Claudia Alvarez; Cantarello, Elena; Echeverría, Cristian; Kitzberger, Thomas; Schiappacasse, Ignacio; Garavito, Natalia Tejedor

    2010-01-01

    Although ecological restoration is widely used to combat environmental degradation, very few studies have evaluated the cost-effectiveness of this approach. We examine the potential impact of forest restoration on the value of multiple ecosystem services across four dryland areas in Latin America, by estimating the net value of ecosystem service benefits under different reforestation scenarios. The values of selected ecosystem services were mapped under each scenario, supported by the use of a spatially explicit model of forest dynamics. We explored the economic potential of a change in land use from livestock grazing to restored native forest using different discount rates and performed a cost–benefit analysis of three restoration scenarios. Results show that passive restoration is cost-effective for all study areas on the basis of the services analyzed, whereas the benefits from active restoration are generally outweighed by the relatively high costs involved. These findings were found to be relatively insensitive to discount rate but were sensitive to the market value of carbon. Substantial variation in values was recorded between study areas, demonstrating that ecosystem service values are strongly context specific. However, spatial analysis enabled localized areas of net benefits to be identified, indicating the value of this approach for identifying the relative costs and benefits of restoration interventions across a landscape. PMID:21106761

  20. Effects of monoclinic symmetry on the properties of biaxial liquid crystals

    Science.gov (United States)

    Solodkov, Nikita V.; Nagaraj, Mamatha; Jones, J. Cliff

    2018-04-01

    Tilted smectic liquid crystal phases such as the smectic-C phase seen in calamitic liquid crystals are usually treated using the assumption of biaxial orthorhombic symmetry. However, the smectic-C phase has monoclinic symmetry, thereby allowing disassociation of the principal optic and dielectric axes based on symmetry and invariance principles. This is demonstrated here by comparing optical and dielectric measurements for two materials with highly first-order direct transitions from nematic to smectic-C phases. The results show a high difference between the orientations of the principal axes sets, which is interpreted as the existence of two distinct cone angles for optical and dielectric frequencies. Both materials exhibit an increasing degree of monoclinic behavior with decreasing temperature. Due to fast switching speeds, ferroelectric smectic-C* materials are important for fast modulators and LCoS devices, where the dielectric biaxiality influences device operation.

  1. P1-30: Axis Orientation Effects on Interaction between Color-Selective Symmetry Detectors

    Directory of Open Access Journals (Sweden)

    Chia-Ching Wu

    2012-10-01

    Full Text Available We used a noise masking paradigm to examine the interaction between color-selective symmetry detection mechanisms in the visual system. We used a 2AFC paradigm in which a random dot noise mask was presented in both intervals. One interval contained a target, while the other, a random dot control. The target consisted of a red and a green symmetric pattern with the same (both were 45° or −45° or orthogonal (one 45°and the other −45° orientation. The observers were to determine which interval contained the symmetric target. We measured the target density threshold at various noise densities. For all conditions, the target density threshold increased with noise density with a slope 0.96 on log-log coordinates. The threshold for the same-orientation condition was lower than that for the orthogonal condition at all noise densities. We fit our data with a divisive inhibition model for symmetry pattern detection (Chen & Tyler, 2010 PLOS One, in which the response of a symmetry detector is the excitation of a linear symmetry operator raised to a power and then divided by the divisive inhibition from all relevant symmetry operators. The best fit showed that the mutual inhibition between symmetry detectors in the same-orientation condition was only 13% of that in the orthogonal condition. Hence, instead of a strong same-orientation inhibition commonly observed in experiments using Gabor patches, it is actually easier for the visual system to integrate symmetric patterns of the same symmetric axis.

  2. Symmetry, Symmetry Breaking and Topology

    Directory of Open Access Journals (Sweden)

    Siddhartha Sen

    2010-07-01

    Full Text Available The ground state of a system with symmetry can be described by a group G. This symmetry group G can be discrete or continuous. Thus for a crystal G is a finite group while for the vacuum state of a grand unified theory G is a continuous Lie group. The ground state symmetry described by G can change spontaneously from G to one of its subgroups H as the external parameters of the system are modified. Such a macroscopic change of the ground state symmetry of a system from G to H correspond to a “phase transition”. Such phase transitions have been extensively studied within a framework due to Landau. A vast range of systems can be described using Landau’s approach, however there are also systems where the framework does not work. Recently there has been growing interest in looking at such non-Landau type of phase transitions. For instance there are several “quantum phase transitions” that are not of the Landau type. In this short review we first describe a refined version of Landau’s approach in which topological ideas are used together with group theory. The combined use of group theory and topological arguments allows us to determine selection rule which forbid transitions from G to certain of its subgroups. We end by making a few brief remarks about non-Landau type of phase transition.

  3. Low Density Symmetry Energy Effects and the Neutron Star Crust Properties

    International Nuclear Information System (INIS)

    Kubis, S.; Alvarez-Castillo, D.E.; Porebska, J.

    2010-01-01

    The form of the nuclear symmetry energy E s around saturation point density leads to a different crust-core transition point in the neutron star and affects the crust properties. We show that the knowledge of E s close to the saturation point is not sufficient to determine the position of the transition point and the very low density behaviour is required. We also claim that crust properties are strongly influenced by the very high density behaviour of E s , so in order to conclude about the form of low density part of the symmetry energy from astrophysical data one must isolate properly the high density part. (authors)

  4. Visualization of anomalous Ettingshausen effect in a ferromagnetic film: Direct evidence of different symmetry from spin Peltier effect

    Science.gov (United States)

    Seki, T.; Iguchi, R.; Takanashi, K.; Uchida, K.

    2018-04-01

    Spatial distribution of temperature modulation due to the anomalous Ettingshausen effect (AEE) is visualized in a ferromagnetic FePt thin film with in-plane and out-of-plane magnetizations using the lock-in thermography technique. Comparing the AEE of FePt with the spin Peltier effect (SPE) of a Pt/yttrium iron garnet junction provides direct evidence of different symmetries of AEE and SPE. Our experiments and numerical calculations reveal that the distribution of heat sources induced by AEE strongly depends on the direction of magnetization, leading to the remarkable different temperature profiles in the FePt thin film between the in-plane and perpendicularly magnetized configurations.

  5. The effect of clinical performance on the survival estimates of direct restorations

    Directory of Open Access Journals (Sweden)

    Kyou-Li Kim

    2013-02-01

    Full Text Available Objectives In most retrospective studies, the clinical performance of restorations had not been considered in survival analysis. This study investigated the effect of including the clinically unacceptable cases according to modified United States Public Health Service (USPHS criteria into the failed data on the survival analysis of direct restorations as to the longevity and prognostic variables. Materials and Methods Nine hundred and sixty-seven direct restorations were evaluated. The data of 204 retreated restorations were collected from the records, and clinical performance of 763 restorations in function was evaluated according to modified USPHS criteria by two observers. The longevity and prognostic variables of the restorations were compared with a factor of involving clinically unacceptable cases into the failures using Kaplan-Meier survival analysis and Cox proportional hazard model. Results The median survival times of amalgam, composite resin and glass ionomer were 11.8, 11.0 and 6.8 years, respectively. Glass ionomer showed significantly lower longevity than composite resin and amalgam. When clinically unacceptable restorations were included into the failure, the median survival times of them decreased to 8.9, 9.7 and 6.4 years, respectively. Conclusions After considering the clinical performance, composite resin was the only material that showed a difference in the longevity (p < 0.05 and the significantly higher relative risk of student group than professor group disappeared in operator groups. Even in the design of retrospective study, clinical evaluation needs to be included.

  6. Universe symmetries

    International Nuclear Information System (INIS)

    Souriau, J.M.

    1984-01-01

    The sky uniformity can be noticed in studying the repartition of objects far enough. The sky isotropy description uses space rotations. The group theory elements will allow to give a meaning at the same time precise and general to the word a ''symmetry''. Universe models are reviewed, which must have both of the following qualities: - conformity with the physic known laws; - rigorous symmetry following one of the permitted groups. Each of the models foresees that universe evolution obeys an evolution equation. Expansion and big-bang theory are recalled. Is universe an open or closed space. Universe is also electrically neutral. That leads to a work hypothesis: the existing matter is not given data of universe but it appeared by evolution from nothing. Problem of matter and antimatter is then raised up together with its place in universe [fr

  7. The thermodynamic Casimir effect with symmetry-preserving and symmetry-breaking boundary conditions; Der thermodynamische Casimir-Effekt mit symmetrieerhaltenden und symmetriebrechenden Randbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Felix

    2014-07-16

    When macroscopic bodies are immersed in fluctuating media, long-range forces between these bodies may occur. The fluctuation's spectrum is modified resulting in a dependence of the system's energy on the separation between the objects, straightforwardly leading to the existence of a force between the bodies. This work is dedicated to the analysis of how boundary conditions affect the thermodynamic Casimir effect where thermal fluctuations near a critical point induce these forces. O(n) symmetric φ 4 theories in d-dimensional slab geometries of thickness L are considered. When symmetry breaking external fields are present as well, the generic boundary conditions of these theories read ∂{sub n}φ-c{sub j}φ=-h{sub j} where the coefficients c{sub j} are surface couplings, serving as linearly extrapolated penetration depths into the surfaces in Landau theory, and h{sub j} are surface fields. The influence of the surface couplings c{sub j} on the Casimir force is investigated by means of the renormalization-group-improved perturbation theory in d=4-ε dimensions to two-loop order at the bulk critical point. Special attention is paid to the case of critical enhancement of the surface interactions which results in the existence of a zero mode leading to a breakdown of the usual loop expansion of the free energy and implicating the emergence of non-integer powers of ε in the ε expansion. These perturbative methods are restricted to the disordered phase with T≥T{sub c,∞}, c{sub j}≥c{sub sp}, and h{sub j}=0. In order to extend the analysis to the whole temperature axis, the exactly treatable limit n → ∞ of the three-dimensional φ 4 model is investigated. A set of self-consistent equations for the free energy is derived that can be solved numerically exact. Considering Dirichlet boundary conditions and vanishing external fields, one finds a temperature dependence of the Casimir force that exhibits the qualitative features of the experimentally

  8. Effects of natural-channel-design restoration on habitat quality in Catskill Mountain streams, New York

    Science.gov (United States)

    Ernst, Anne G.; Baldigo, Barry P.; Mulvihill, Christiane; Vian, Mark

    2010-01-01

    Stream restoration has received much attention in recent years, yet there has been little effort to evaluate its impacts on physical habitat, stability, and biota. A popular but controversial stream restoration approach is natural channel design (NCD), which cannot be adequately evaluated without a long-term, independent assessment of its effects on stream habitat. Six reaches of five Catskill Mountain streams in southeastern New York were restored during 2000–2003 following NCD techniques to decrease bed and bank degradation, decrease sediment loads, and improve water quality. Habitat surveys were conducted during summer low flows from 2001 to 2007. The effects of the NCD projects on stream condition were assessed via a before–after–control–impact study design to quantify the net changes in stream and bank habitat variables relative to those in unaltered control reaches. Analysis of variance tests of three different measures of bank stability show that on average stream stability increased at treatment sites for 2–5 years after restoration. Mean channel depth, thalweg depth, and the pool–riffle ratio generally increased, whereas mean channel width, percent streambank coverage by trees, and shade decreased. Habitat suitability indices for local salmonid species increased at four of six reaches after restoration. The changes in channel dimensions rendered them generally more characteristic of stabler stream forms in the given valley settings. Although these studies were done relatively soon after project completion, our findings demonstrate that habitat conditions can be improved in degraded Catskill Mountain streams through NCD restoration.

  9. Using Habitat Equivalency Analysis to Assess the Cost Effectiveness of Restoration Outcomes in Four Institutional Contexts

    Science.gov (United States)

    Scemama, Pierre; Levrel, Harold

    2016-01-01

    At the national level, with a fixed amount of resources available for public investment in the restoration of biodiversity, it is difficult to prioritize alternative restoration projects. One way to do this is to assess the level of ecosystem services delivered by these projects and to compare them with their costs. The challenge is to derive a common unit of measurement for ecosystem services in order to compare projects which are carried out in different institutional contexts having different goals (application of environmental laws, management of natural reserves, etc.). This paper assesses the use of habitat equivalency analysis (HEA) as a tool to evaluate ecosystem services provided by restoration projects developed in different institutional contexts. This tool was initially developed to quantify the level of ecosystem services required to compensate for non-market impacts coming from accidental pollution in the US. In this paper, HEA is used to assess the cost effectiveness of several restoration projects in relation to different environmental policies, using case studies based in France. Four case studies were used: the creation of a market for wetlands, public acceptance of a port development project, the rehabilitation of marshes to mitigate nitrate loading to the sea, and the restoration of streams in a protected area. Our main conclusion is that HEA can provide a simple tool to clarify the objectives of restoration projects, to compare the cost and effectiveness of these projects, and to carry out trade-offs, without requiring significant amounts of human or technical resources.

  10. Modeling the effects of ion dose and crystallographic symmetry on the morphological evolution of embedded precipitates under thermal annealing

    International Nuclear Information System (INIS)

    Li, Kun-Dar

    2014-01-01

    Highlights: •We model the faceted precipitates formation by post-implantation annealing. •The anisotropic interfacial energy and diffusion kinetics play crucial roles. •The evolutions of faceted precipitates, including Ostwald ripening, are revealed. •The mechanism of the nucleation and growth is based on the atomic diffusion. •The effects of ion dose and crystallographic symmetry are also investigated. -- Abstract: Thermal annealing is one of the most common techniques to synthesize embedded precipitates by ion implantation process. In this study, an anisotropic phase field model is presented to investigate the effects of ion dose and crystallographic symmetry on the morphological formation and evolution of embedded precipitates during post-implantation thermal annealing process. This theoretical model provides an efficient numerical approach to understand the phenomenon of faceted precipitates formation by ion implantation. As a theoretical analysis, the interfacial energy and diffusion kinetics play prominent roles in the mechanism of atomic diffusion for the precipitates formation. With a low ion dose, faceted precipitates are developed by virtue of the anisotropic interfacial energy. As an increase of ion dose, connected precipitates with crystallographic characters on the edge are appeared. For a high ion dose, labyrinth-like nanostructures of precipitates are produced and the characteristic morphology of crystallographic symmetry becomes faint. These simulation results for the morphological evolutions of embedded precipitates by ion implantation are corresponded with many experimental observations in the literatures. The quantitative analyses of the simulations are also well described the consequence of precipitates formation under different conditions

  11. Acute effects of unilateral whole body vibration training on single leg vertical jump height and symmetry in healthy men.

    Science.gov (United States)

    Shin, Seungho; Lee, Kyeongjin; Song, Changho

    2015-12-01

    [Purpose] The aim of the present study was to investigate the acute effects of unilateral whole body vibration training on height and symmetry of the single leg vertical jump in healthy men. [Subjects] Thirty males with no history of lower limb dysfunction participated in this study. [Methods] The participants were randomly allocated to one of three groups: the unilateral vibratory stimulation group (n=10), bilateral vibratory stimulation group (n=10), and, no vibratory stimulation group (n=10). The subjects in the unilateral and bilateral stimulation groups participated in one session of whole body vibration training at 26 Hz for 3 min. The no vibratory stimulation group subjects underwent the same training for 3 min without whole body vibration. All participants performed the single leg vertical jump for each lower limb, to account for the strong and weak sides. The single leg vertical jump height and symmetry were measured before and after the intervention. [Results] The single leg vertical jump height of the weak lower limb significantly improved in the unilateral vibratory stimulation group, but not in the other groups. The single leg vertical jump height of the strong lower limb significantly improved in the bilateral vibratory stimulation group, but not in the other groups. The single leg vertical jump symmetry significantly improved in the unilateral vibratory stimulation group, but not in the other groups. [Conclusion] Therefore, the present study found that the effects of whole body vibration training were different depending on the type of application. To improve the single leg vertical jump height in the weak lower limbs as well as limb symmetry, unilateral vibratory stimulation might be more desirable.

  12. Formulation of the low-energy effective theory of electroweak symmetry-breaking without a Higgs particle

    International Nuclear Information System (INIS)

    Hirn, J.

    2004-07-01

    The low-energy effective theory of electroweak symmetry-breaking without a Higgs particle is constructed using the methods of Chiral Perturbation Theory. Weinberg's power-counting formula demonstrates the consistency of the loop expansion, with the corresponding renormalization. We find that the suppression of effective operators by a mass scale, which was automatic in the case of the Standard Model, no longer holds in the Higgs-less case. Moreover, the incriminated operators appear at leading order in the chiral expansion, at variance with experiments. To account for their suppression, invariance under a larger symmetry is required, corresponding to the composite sector (which produces the three Goldstone modes) being decoupled from the elementary sector (quarks, leptons and Yang-Mills fields). The couplings are introduced via spurions: this reduces the symmetry to SU(2) x U(1). In the simultaneous expansion in powers of momenta and spurions, the aforementioned operators are relegated to higher orders. In addition, the method allows for a systematic treatment of weak isospin breaking. The Weinberg power-counting formula can be recovered, and small neutrino masses accounted for. The three right-handed neutrinos (lighter than the TeV), which are introduced in connection with the custodial symmetry, are quasi-sterile and stable. A constraint on the underlying theory is obtained by studying the anomaly-matching in the composite sector and generalizing the Wess-Zumino construction. The spurion formalism is also applied to open linear moose models, for which generalized Weinberg sum rules are derived. (author)

  13. Alternative Experimental Evidence for Chiral Restoration in Excited Baryons

    International Nuclear Information System (INIS)

    Glozman, L. Ya.

    2007-01-01

    It has been suggested that chiral symmetry is approximately restored in excited hadrons at zero temperature and density (effective symmetry restoration). Using very general chiral symmetry arguments, it is shown that those excited nucleons that are assumed from the spectroscopic patterns to be in approximate chiral multiplets must only weakly decay into the Nπ channel (f N*Nπ /f NNπ ) 2 NNπ . It turns out that for all those well-established excited nucleons which can be classified into chiral doublets the ratio is (f N*Nπ /f NNπ ) 2 ∼0.1 or much smaller for the high-spin states. In contrast, the only well-established excited nucleon for which the chiral partner cannot be identified from the spectroscopic data, N(1520), has a decay constant into the Nπ channel that is comparable with f NNπ

  14. The effect of crystal symmetry on the maximum polarization of polycrystalline ferroelectric materials

    International Nuclear Information System (INIS)

    Jones, Jacob L.

    2010-01-01

    In polycrystalline ceramics, the degree of domain orientation in all possible crystal orientations contributes to the total realizable polarization. The extent to which domains are oriented towards an applied field can be described by a polarization distribution function. Such representations are calculated and presented in the present work for several different crystal systems including monoclinic symmetries that exhibit a polarization rotation mechanism. The relationship between the polarization distribution functions and the attainable macroscopic polarization is also developed for polycrystalline ceramics that are initially randomly oriented. In these cases, polarization rotation allows a significant degree of preferred orientation parallel to the electric field (>1000 multiples of a random distribution). However, the fraction of single crystal polarization that can be achieved (97.5%) is only marginally better than those of higher crystal symmetry.

  15. Truncation effects in the functional renormalization group study of spontaneous symmetry breaking

    International Nuclear Information System (INIS)

    Defenu, N.; Mati, P.; Márián, I.G.; Nándori, I.; Trombettoni, A.

    2015-01-01

    We study the occurrence of spontaneous symmetry breaking (SSB) for O(N) models using functional renormalization group techniques. We show that even the local potential approximation (LPA) when treated exactly is sufficient to give qualitatively correct results for systems with continuous symmetry, in agreement with the Mermin-Wagner theorem and its extension to systems with fractional dimensions. For general N (including the Ising model N=1) we study the solutions of the LPA equations for various truncations around the zero field using a finite number of terms (and different regulators), showing that SSB always occurs even where it should not. The SSB is signalled by Wilson-Fisher fixed points which for any truncation are shown to stay on the line defined by vanishing mass beta functions.

  16. Effects of mirror symmetry on the transmission fingerprints of quasiperiodic photonic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, I.P. [Departamento de Ensino Superior, Instituto Federal de Educacao, Ciencia e Tecnologia do Maranhao, Campus Imperatriz, 65919-050 Imperatriz, MA (Brazil); Vasconcelos, M.S., E-mail: mvasconcelos@ect.ufrn.b [Escola de Ciencias e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Bezerra, C.G. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil)

    2010-03-29

    We address the transmission properties of light waves through symmetric Fibonacci, Thue-Morse and double-period photonic multilayers, i.e., a binary one-dimensional quasiperiodic structure made up of two different dielectric materials (more specifically SiO{sub 2} and TiO{sub 2}), in quarter wavelength condition, presenting mirror symmetry. The optical spectra are calculated by using a theoretical model based on the transfer matrix approach in normal incidence geometry. In our results we present the self-similar features of the spectra and we also present the optical fingerprints through a return map of the transmission coefficients. We discuss these optical fingerprints and compare them with results of previous works, on similar quasiperiodic systems, in the absence of mirror symmetry.

  17. Effects of mirror symmetry on the transmission fingerprints of quasiperiodic photonic multilayers

    International Nuclear Information System (INIS)

    Coelho, I.P.; Vasconcelos, M.S.; Bezerra, C.G.

    2010-01-01

    We address the transmission properties of light waves through symmetric Fibonacci, Thue-Morse and double-period photonic multilayers, i.e., a binary one-dimensional quasiperiodic structure made up of two different dielectric materials (more specifically SiO 2 and TiO 2 ), in quarter wavelength condition, presenting mirror symmetry. The optical spectra are calculated by using a theoretical model based on the transfer matrix approach in normal incidence geometry. In our results we present the self-similar features of the spectra and we also present the optical fingerprints through a return map of the transmission coefficients. We discuss these optical fingerprints and compare them with results of previous works, on similar quasiperiodic systems, in the absence of mirror symmetry.

  18. Optical anisotropy of non-common-atom quantum wells and dots: effects of interface symmetry reduction

    International Nuclear Information System (INIS)

    Toropov, A.A.; Sorokin, S.V.; Shubina, T.V.; Nekrutkina, O.V.; Solnyshkov, D.D.; Ivanov, S.V.; Waag, A.; Landwehr, G.

    2003-01-01

    We report on the investigations of in-plane optical anisotropy in non-common-atom heterostructures: ZnSe/BeTe perfect quantum wells (QWs) and CdSe/BeTe rough QWs and quantum dots. A noticeable linear polarization of photoluminescence (PL) with respect to the in-plane [1-10] and [110] crystal axes was observed in the ZnSe/BeTe QWs with equivalent ZnTe-type interfaces due to the reduction of QW symmetry, induced by unintentional formation of BeSe chemical bonds at a ''BeTe-ZnSe'' interface. The BeSe bond concentration and, hence, the polarization degree depend on the Te/Be flux ratio during molecular beam epitaxy growth of the samples. Strongly linearly polarized (up to 80%) PL was detected in the CdSe/BeTe structures, evidencing QW-like flat symmetry of the emitting sites of carrier localization. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Effects of body-weight supported treadmill training on kinetic symmetry in persons with chronic stroke.

    Science.gov (United States)

    Combs, Stephanie A; Dugan, Eric L; Ozimek, Elicia N; Curtis, Amy B

    2012-11-01

    The purpose was to examine changes in kinetic symmetry in persons with chronic stroke immediately and 6-months after body-weight supported treadmill training. Fifteen participants at least six-months post stroke and able to ambulate between 0.4 and 0.8m/s and 20 participants without neurological conditions completed all phases of the study and were included in the analysis. The non-disabled group served as a comparison for describing changes in kinetic symmetry. The stroke group completed 24 sessions of body-weight supported treadmill training over 8-weeks with 20 minutes of total walking per session. Bilateral 3-dimensional motion analysis and gait speed were assessed 1-week before training (pre-test), 1-week after training (post-test) and 6-months after training (retention) in a repeated measures design. Relative propulsion of the paretic leg and relative positive work of the hip, knee and ankle joints of both legs were calculated to evaluate symmetry of kinetic forces. Statistically significant differences in relative propulsion and positive joint work within the paretic and non-paretic legs were not found over time. The stroke group significantly improved gait speed from pre- to post-test (p=.001) and pre-test to retention (p=.008). In comparison to the non-disabled group, forces produced by the stroke group were asymmetrical demonstrating compensatory adaptation. Although the participants with chronic stroke walked faster after body-weight supported treadmill training, the relative percentages of propulsion and positive work remained unchanged. These findings suggest that the increase in speed was likely due to strengthening existing compensatory strategies rather than through recovery of normal kinetic symmetry. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Berryman, J.G.

    2010-05-15

    For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizontal transversely isotropic) symmetry transform into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI (vertical transversely isotropic) symmetry if all of the fractures are aligned randomly or half parallel and half perpendicular to a given vertical plane. An orthotropic example having vertical fractures in an otherwise VTI earth system (studied previously by Schoenberg and Helbig) is compared with the other examples treated and it is finally shown how fluids in the fractures affect the orthotropic poroelastic system response to seismic waves. The key result is that fracture-influence parameters are multiplied by a factor of (1-B), where 0 {le} B < 1 is Skempton's second coefficient for poroelastic media. Skempton's B coefficient is itself a measurable characteristic of fluid-saturated porous rocks, depending on porosity, solid moduli, and the pore-fluid bulk modulus. For heterogeneous porous media, connections between the present work and earlier related results of Brown and Korringa are also established.

  1. Symmetry restoration in spontaneously broken induced gravity

    International Nuclear Information System (INIS)

    Amati, D.; Russo, J.

    1990-01-01

    We investigate the recuperation of expected invariant behaviours in a non-metric gravity theory in which the full general relativistic invariance is broken spontaneously. We show how dangerous increasing energy behaviours of physical amplitudes cancel in a highly non-trivial way. This evidences the expected loss of the vacuum generated scale in the UV regime and gives support for the consistency of spontaneously broken gravity theories. (orig.)

  2. Effects of functional restoration versus 3 hours per week physical therapy: a randomized controlled study.

    Science.gov (United States)

    Jousset, Nathalie; Fanello, Serge; Bontoux, Luc; Dubus, Valérie; Billabert, Colette; Vielle, Bruno; Roquelaure, Yves; Penneau-Fontbonne, Dominique; Richard, Isabelle

    2004-03-01

    Randomized parallel-group comparative trial with a 6-month follow-up period. To compare, in chronic low back pain patients, the effectiveness of a functional restoration program, including intensive physical training, occupational therapy, and psychological support to an active individual therapy consisting of 3 hours physical therapy per week during 5 weeks. Controlled studies conducted in the United States showed a benefit of functional restoration in patients with low back pain, especially on return to work. Randomized Canadian and European trials had less favorable results. In France, there has been up to now no randomized study. Controlled studies suggested a positive effect of functional restoration programs. Eighty-six patients with low back pain were randomized to either the functional restoration (44 patients) or the active individual therapy (42 patients) program. One person in each group never started the program. Two patients did not complete the functional restoration program, and one was lost to follow-up at 6 months. The mean number of sick-leave days in the 2 previous years was 6 months. After adjustment on the variable "workplace enrolled in an ergonomic program", the mean number of sick-leave days was significantly lower in the functional restoration group. Physical criteria and treatment appreciation were also better. There was no significant difference in the intensity of pain, the quality of life and functional indexes, the psychological characteristics, the number of contacts with the medical system, and the drug intake. This study demonstrates the effectiveness of a functional restoration program on important outcome measures, such as sick leave, in a country that has a social system that protects people facing difficulties at work.

  3. Effect of dual-cure composite resin as restorative material on marginal adaptation of class 2 restorations.

    Science.gov (United States)

    Bortolotto, Tissiana; Melian, Karla; Krejci, Ivo

    2013-10-01

    The present study attempted to find a simple direct adhesive restorative technique for the restoration of Class 2 cavities. A self-etch adhesive system with a dual-cured core buildup composite resin (paste 1 + paste 2) was evaluated in its ability to restore proximo-occlusal cavities with margins located on enamel and dentin. The groups were: A, cavity filling (cf) with paste 1 (light-curing component) by using a layering technique; B, cf by mixing both pastes, bulk insertion, and dual curing; and C, cf by mixing both pastes, bulk insertion, and chemical curing. Two control groups (D, negative, bulk; and E, positive, layering technique) were included by restoring cavities with a classic three-step etch-and-rinse adhesive and a universal restorative composite resin. SEM margin analysis was performed before and after thermomechanical loading in a chewing simulator. Percentages (mean ± SD) of "continuous margins" were improved by applying the material in bulk and letting it self cure (54 ± 6) or dual cure (59 ± 9), and no significant differences were observed between these two groups and the positive control (44 ± 19). The present study showed that the dual-cured composite resin tested has the potential to be used as bulk filling material for Class 2 restorations. When used as filling materials, dual-cure composite resins placed in bulk can provide marginal adaptation similar to light-cured composites applied with a complex stratification technique.

  4. Symmetry-improved 2PI approach to the Goldstone-boson IR problem of the SM effective potential

    Directory of Open Access Journals (Sweden)

    Apostolos Pilaftsis

    2016-05-01

    Full Text Available The effective potential of the Standard Model (SM, from three loop order and higher, suffers from infrared (IR divergences arising from quantum effects due to massless would-be Goldstone bosons associated with the longitudinal polarizations of the W± and Z bosons. Such IR pathologies also hinder accurate evaluation of the two-loop threshold corrections to electroweak quantities, such as the vacuum expectation value of the Higgs field. However, these divergences are an artifact of perturbation theory, and therefore need to be consistently resummed in order to obtain an IR-safe effective potential. The so-called Two-Particle-Irreducible (2PI effective action provides a rigorous framework to consistently perform such resummations, without the need to resort to ad hoc subtractions or running into the risk of over-counting contributions. By considering the recently proposed symmetry-improved 2PI formalism, we address the problem of the Goldstone-boson IR divergences of the SM effective potential in the gaugeless limit of the theory. In the same limit, we evaluate the IR-safe symmetry-improved 2PI effective potential, after taking into account quantum loops of chiral fermions, as well as the renormalization of spurious custodially breaking effects triggered by fermionic Yukawa interactions. Finally, we compare our results with those obtained with other methods presented in the literature.

  5. The effect of baking soda when applied to bleached enamel prior to restorative treatment.

    Science.gov (United States)

    Tostes, Bhenya Ottoni; Mondelli, Rafael Francisco Lia; Lima-Arsati, Ynara Bosco de Oliveira; Rodrigues, Jose Augusto; Costa, Leonardo Cesar

    2013-08-01

    This in vitro study evaluated the effect of 10% baking soda solution and sodium bicarbonate powder (applied with jets) when applied to bleached enamel prior to restorative treatment. The surfaces of 40 bovine incisors were flattened and divided into 5 groups (n = 8): Group B (bleached and restored, negative control), Group W (bleached, stored in distilled water for 7 days, and restored), Group BSJ (bleached, abraded with baking soda jet for 1 min, and restored), Group BSS (bleached, application of 10% baking soda solution for 5 min, and restored), and Group R (restored, without bleaching, positive control). The samples were bleached in 1 session with 3 applications of 35% HP-based gel and activated with a LED appliance for 9 min each. Resin composite cylinders (2 mm height and 0.8 mm diameter) were made on the enamel surface after the acid etching and a conventional 1-step single vial adhesive application was performed. After storage in distilled water (37 ± 1°C, 24 hr), the microshear bond test was performed (1 mm/min). ANOVA and Tukey tests were applied to compare the results. The mean results of these tests showed that Groups W, BBS, and R were not statistically different. These groups also indicated a higher bond strength when compared with Groups B and BSJ. The application of 10% baking soda solution for 5 min may be an alternative pre-restorative treatment for bleached enamel, but further studies are needed to consider whether or not this treatment may be effectively used in clinical practice.

  6. Introduction to Chiral Symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Volker [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-05-09

    These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. We will also discuss some effective chiral models such as the linear and nonlinear sigma model as well as the essential ideas of chiral perturbation theory. We will present some applications to the physics of ultrarelativistic heavy ion collisionsd.

  7. Introduction to chiral symmetry

    International Nuclear Information System (INIS)

    Koch, V.

    1996-01-01

    These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented

  8. Collective states and crossing symmetry

    International Nuclear Information System (INIS)

    Heiss, W.D.

    1977-01-01

    Collective states are usually described in simple terms but with the use of effective interactions which are supposed to contain more or less complicated contributions. The significance of crossing symmetry is discussed in this connection. Formal problems encountered in the attempts to implement crossing symmetry are pointed out

  9. Soil indicators to assess the effectiveness of restoration strategies in dryland ecosystems

    Science.gov (United States)

    Costantini, Edoardo; Branquinho, Cristina; Nunes, Alice; Schwilch, Gudrun; Stavi, Ilan; Valdecantos, Alejandro; Zucca, Claudio

    2016-04-01

    Soil indicators may be used for assessing both land suitability for restoration and the effectiveness of restoration strategies in restoring ecosystem functioning and services. In this review paper, several soil indicators, which can be used to assess the effectiveness of restoration strategies in dryland ecosystems at different spatial and temporal scales, are discussed. The selected indicators represent the different viewpoints of pedology, ecology, hydrology, and land management. The recovery of soil capacity to provide ecosystem services is primarily obtained by increasing soil rooting depth and volume, and augmenting water accessibility for vegetation. Soil characteristics can be used either as indicators of suitability, that is, inherently slow-changing soil qualities, or as indicators for modifications, namely dynamic, thus "manageable" soil qualities. Soil organic matter forms, as well as biochemistry, micro- and meso-biology, are among the most utilized dynamic indicators. On broader territorial scales, the Landscape Function Analysis uses a functional approach, where the effectiveness of restoration strategies is assessed by combining the analysis of spatial pattern of vegetation with qualitative soil indicators. For more holistic and comprehensive projects, effective strategies to combat desertification should integrate soil indicators with biophysical and socio-economic evaluation and include participatory approaches. The integrated assessment protocol of Sustainable Land Management developed by the World Overview of Conservation Approaches and Technologies network is thoroughly discussed. Two overall outcomes stem from the review: i) the success of restoration projects relies on a proper understanding of their ecology, namely the relationships between soil, plants, hydrology, climate, and land management at different scales, which is particularly complex due to the heterogeneous pattern of ecosystems functioning in drylands, and ii) the selection of

  10. Interim restorations.

    Science.gov (United States)

    Gratton, David G; Aquilino, Steven A

    2004-04-01

    Interim restorations are a critical component of fixed prosthodontic treatment, biologically and biomechanically. Interim restoration serves an important diagnostic role as a functional and esthetic try-in and as a blueprint for the design of the definitive prosthesis. When selecting materials for any interim restoration, clinicians must consider physical properties, handling properties, patient acceptance, and material cost. Although no single material meets all the requirements and material classification alone of a given product is not a predictor of clinical performance, bis-acryl materials are typically best suited to single-unit restorations, and poly(methylmethacrylate) interim materials are generally ideal for multi-unit, complex, long-term, interim fixed prostheses. As with most dental procedures, the technique used for fabrication has a greater effect on the final result than the specific material chosen.

  11. Evaluating the effect of river restoration techniques on reducing the impacts of outfall on water quality

    Science.gov (United States)

    Mant, Jenny; Janes, Victoria; Terrell, Robert; Allen, Deonie; Arthur, Scott; Yeakley, Alan; Morse, Jennifer; Holman, Ian

    2015-04-01

    Outfalls represent points of discharge to a river and often contain pollutants from urban runoff, such as heavy metals. Additionally, erosion around the outfall site results in increased sediment generation and the release of associated pollutants. Water quality impacts from heavy metals pose risks to the river ecosystem (e.g. toxicity to aquatic habitats). Restoration techniques including establishment of swales, and the re-vegetation and reinforcement of channel banks aim to decrease outfall flow velocities resulting in deposition of pollutants and removal through plant uptake. Within this study the benefits of river restoration techniques for the removal of contaminants associated with outfalls have been quantified within Johnson Creek, Portland, USA as part of the EPSRC funded Blue-Green Cities project. The project aims to develop new strategies for protecting hydrological and ecological values of urban landscapes. A range of outfalls have been selected which span restored and un-restored channel reaches, a variety of upstream land-uses, and both direct and set-back outfalls. River Habitat Surveys were conducted at each of the sites to assess the level of channel modification within the reach. Sediment samples were taken at the outfall location, upstream, and downstream of outfalls for analysis of metals including Nickel, Lead, Zinc, Copper, Iron and Magnesium. These were used to assess the impact of the level of modification at individual sites, and to compare the influence of direct and set-back outfalls. Concentrations of all metals in the sediments found at outfalls generally increased with the level of modification at the site. Sediment in restored sites had lower metal concentrations both at the outfall and downstream compared to unrestored sites, indicating the benefit of these techniques to facilitate the effective removal of pollutants by trapping of sediment and uptake of contaminants by vegetation. However, the impact of restoration measures varied

  12. Effects of victim presence and coercion in restorative justice: An experimental paradigm.

    Science.gov (United States)

    Saulnier, Alana; Sivasubramaniam, Diane

    2015-08-01

    There is little experimental work examining the ways in which particular procedural features of restorative justice impact offenders. This research describes a new experimental paradigm designed to advance knowledge about causal relationships in restorative justice settings. Apologizing is a core component of restorative procedures, and can result in beneficial outcomes, but previous research suggests that coercion to apologize and the absence of victims in restorative procedures may negatively impact these outcomes. The experimental procedure elicited confessions and apologies for a transgression from participants (N = 101) in a deceptive paradigm. We manipulated coercion (coerced, not coerced) and victim presence (direct, surrogate, ambiguous) to test their effects on offenders' subjective experiences of offering an apology, as well as their effects on the quality of offenders' apologies. Findings indicated that the victim presence and coercion manipulations significantly impacted some of the subjective perceptions of apologizers, including perceptions of accountability and transgression finality. In addition, independent raters evaluated the degree to which the transgressor's apologies conveyed remorse, acceptance of guilt, and potential for dispute resolution. Victim presence and coercion consistently affected the ability of transgressors to convey high quality apologies. Implications for future research and restorative procedures are discussed. (c) 2015 APA, all rights reserved).

  13. Symmetry of nonexploding cylindrical liner converging to the axis under magnetic field effects

    International Nuclear Information System (INIS)

    Chernyshev, V.K.; Grinevich, B.E.; Buzin, V.N.; Pogorelov, V.P.; Shertsov, V.A.; Petrukhin, A.A.; Demidov, V.A.; Zharinov, E.I.

    1990-01-01

    Liner acceleration, affected by magnetic pressure, is broadly used to yield megagauss magnetic fields and plasma compression. The progress of test conduction depends much on the state of liner subjected to Taylor instability while being accelerated. There is a number of methods permitting to reduce liner shape distortions, developing during its acceleration. The most simple method consists in that the aspect ratio (the ratio of liner placing radius to its thickness) is taken less than 10. To impart sufficient velocity to the liner of large thickness its density should be small. Therefore, liner is either a gas layer or explosion products of thin metal foil which passed to a vaporous state in early stage of acceleration. Acceleration of nonexploding liners may serve as the other method of asymmetry reduction. Strength and viscosity of liner will be used as stabilizing factors with respect to the development of Taylor instability. This will allow the aspect ratio increase, that is sometimes useful. Test results on acceleration of nonexploding aluminum liners 1 mm thick have been described. Aspect ratio amounted to 30-60 and the ratio of liner acceleration distance to its thickness (parameter, being of great importance when studying the development of Taylor instability) made up 20-40. Satisfactory azimuthal symmetry of liner convergence to the center was recorded. For more detailed investigation of Taylor instability influence on the symmetry of nonexploding liner, the experiments, when the ratio of liner acceleration length to its thickness would be increased up to 90-100 simultaneously with determination of azimuthal and axial symmetry of liner, are of interest. In this paper presents the results of experiments on acceleration of copper cylindrical liner 1.37 mm thick

  14. Symmetry breaking effect on determination of polarized and unpolarized parton distributions

    International Nuclear Information System (INIS)

    Arbabifar, F.; Khorramian, Ali N.; Khanpour, H.; Atashbar Tehrani, S.

    2013-01-01

    We perform a new extraction for unpolarized and polarized parton distribution functions considering a flavor decompositions for sea quarks and applying very recent deep inelastic scattering (DIS) and semi inclusive deep inelastic scattering (SIDIS) data in the fixed flavor number scheme (FFNS) framework. In the new symmetry breaking scenario the light quark and antiquark densities are extracted separately and new parametrization forms are determined for them. The heavy flavors contribution, including charm and bottom quarks, are also taken to be account for unpolarized distributions

  15. Effects of Sublattice Symmetry and Frustration on Ionic Transport in Garnet Solid Electrolytes

    Science.gov (United States)

    Kozinsky, Boris; Akhade, Sneha A.; Hirel, Pierre; Hashibon, Adham; Elsässer, Christian; Mehta, Prateek; Logeat, Alan; Eisele, Ulrich

    2016-02-01

    We use rigorous group-theoretic techniques and molecular dynamics to investigate the connection between structural symmetry and ionic conductivity in the garnet family of solid Li-ion electrolytes. We identify new ordered phases and order-disorder phase transitions that are relevant for conductivity optimization. Ionic transport in this materials family is controlled by the frustration of the Li sublattice caused by incommensurability with the host structure at noninteger Li concentrations, while ordered phases explain regions of sharply lower conductivity. Disorder is therefore predicted to be optimal for ionic transport in this and other conductor families with strong Li interaction.

  16. Effect of Medium Symmetries in Limiting the Number of Parameters Estimated with Polarimetric Interferometry

    Science.gov (United States)

    Moghaddam, Mahta

    2000-01-01

    The addition of interferometric backscattering pairs to the conventional polarimetric SAR data over forests and other vegetated areas increases the dimensionality of the data space, in principle enabling the estimation of a larger number of vegetation parameters. Without regard to the sensitivity of these data to vegetation scattering parameters, this paper poses the question: Will increasing the data channels as such result in a one-to-one increase in the number of parameters that can be estimated, or do vegetation and data properties inherently limit that number otherwise? In this paper, the complete polarimetric interferometric covariance matrix is considered and various symmetry properties of the scattering medium are used to study whether any of the correlation pairs can be eliminated. The number of independent pairs has direct consequences in their utility in parameter estimation schemes, since the maximum number of parameters that can be estimated cannot exceed the number of unique measurements. The independent components of the polarimetric interferometric SAR (POL/INSAR) data are derived for media with reflection, rotation, and azimuth symmetries, which are often encountered in vegetated surfaces. Similar derivations have been carried out before for simple polarimetry, i.e., zero baseline. This paper extends those to the interferometric case of general nonzero baselines. It is shown that depending on the type of symmetries present, the number of independent available measurements that can be used to estimate medium parameters will vary. In particular, whereas in the general case there are 27 mathematically independent measurements possible from a polarimetric interferometer, this number can be reduced to 15, 9, and 6 if the medium has reflection, rotation, or azimuthal symmetries, respectively. The results can be used in several ways in the interpretation of SAR data and the development of parameter estimation schemes, which will be discussed at the

  17. BOOK REVIEW: Symmetry Breaking

    Science.gov (United States)

    Ryder, L. H.

    2005-11-01

    One of the most fruitful and enduring advances in theoretical physics during the last half century has been the development of the role played by symmetries. One needs only to consider SU(3) and the classification of elementary particles, the Yang Mills enlargement of Maxwell's electrodynamics to the symmetry group SU(2), and indeed the tremendous activity surrounding the discovery of parity violation in the weak interactions in the late 1950s. This last example is one of a broken symmetry, though the symmetry in question is a discrete one. It was clear to Gell-Mann, who first clarified the role of SU(3) in particle physics, that this symmetry was not exact. If it had been, it would have been much easier to discover; for example, the proton, neutron, Σ, Λ and Ξ particles would all have had the same mass. For many years the SU(3) symmetry breaking was assigned a mathematical form, but the importance of this formulation fell away when the quark model began to be taken seriously; the reason the SU(3) symmetry was not exact was simply that the (three, in those days) quarks had different masses. At the same time, and in a different context, symmetry breaking of a different type was being investigated. This went by the name of `spontaneous symmetry breaking' and its characteristic was that the ground state of a given system was not invariant under the symmetry transformation, though the interactions (the Hamiltonian, in effect) was. A classic example is ferromagnetism. In a ferromagnet the atomic spins are aligned in one direction only—this is the ground state of the system. It is clearly not invariant under a rotation, for that would change the ground state into a (similar but) different one, with the spins aligned in a different direction; this is the phenomenon of a degenerate vacuum. The contribution of the spin interaction, s1.s2, to the Hamiltonian, however, is actually invariant under rotations. As Coleman remarked, a little man living in a ferromagnet would

  18. Optical anisotropy of non-common-atom quantum wells and dots: effects of interface symmetry reduction

    Energy Technology Data Exchange (ETDEWEB)

    Toropov, A.A.; Sorokin, S.V.; Shubina, T.V.; Nekrutkina, O.V.; Solnyshkov, D.D.; Ivanov, S.V. [Ioffe Physico-Technical Institute of RAS, St. Petersburg 194021 (Russian Federation); Waag, A. [Abteilung Halbleiterphysik, Universitaet Ulm, 89081 Ulm (Germany); Landwehr, G. [Physikalisches Institut der Universitaet Wuerzburg, D-97074 Wuerzburg (Germany)

    2003-02-01

    We report on the investigations of in-plane optical anisotropy in non-common-atom heterostructures: ZnSe/BeTe perfect quantum wells (QWs) and CdSe/BeTe rough QWs and quantum dots. A noticeable linear polarization of photoluminescence (PL) with respect to the in-plane [1-10] and [110] crystal axes was observed in the ZnSe/BeTe QWs with equivalent ZnTe-type interfaces due to the reduction of QW symmetry, induced by unintentional formation of BeSe chemical bonds at a ''BeTe-ZnSe'' interface. The BeSe bond concentration and, hence, the polarization degree depend on the Te/Be flux ratio during molecular beam epitaxy growth of the samples. Strongly linearly polarized (up to 80%) PL was detected in the CdSe/BeTe structures, evidencing QW-like flat symmetry of the emitting sites of carrier localization. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  19. Applications of chiral symmetry

    International Nuclear Information System (INIS)

    Pisarski, R.D.

    1995-03-01

    The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T χ implies that the ρ and a 1 vector mesons are degenerate in mass. In a gauged linear sigma model the ρ mass increases with temperature, m ρ (T χ ) > m ρ (0). The author conjectures that at T χ the thermal ρ - a 1 , peak is relatively high, at about ∼1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The ω meson also increases in mass, nearly degenerate with the ρ, but its width grows dramatically with temperature, increasing to at least ∼100 MeV by T χ . The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from open-quotes quenchedclose quotes heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates

  20. Effect of bulk-fill base material on fracture strength of root-filled teeth restored with laminate resin composite restorations.

    Science.gov (United States)

    Taha, N A; Maghaireh, G A; Ghannam, A S; Palamara, J E

    2017-08-01

    To evaluate the effect of using a bulk-fill flowable base material on fracture strength and fracture patterns of root-filled maxillary premolars with MOD preparations restored with laminate restorations. Fifty extracted maxillary premolars were selected for the study. Standardized MOD cavities with endodontic treatment were prepared for all teeth, except for intact control. The teeth were divided randomly into five groups (n=10); (Group 1) sound teeth, (Group 2) unrestored teeth; (Group 3) MOD cavities with Vitrebond base and resin-based composite (Ceram. X One Universal); (Group 4) MOD cavities with 2mm GIC base (Fuji IX GP) and resin-based composite (Ceram. X One Universal) open laminate, (Group 5) MOD cavities were restored with 4mm of bulk-fill flowable base material (SDR) and resin-based composite (Ceram. X One Universal). All teeth were thermocycled and subjected to a 45° ramped oblique load in a universal testing machine. Fracture load and fracture patterns were recorded. Data were analyzed using one-way ANOVA and Dunnett's T3 test. Restoration in general increased the fracture strength compared to unrestored teeth. The fracture strength of group 5 (bulk-fill) was significantly higher than the fracture strength of the GIC laminate groups and not significantly different from the intact teeth (355±112N, P=0.118). The type of failure was unfavorable for most of the groups, with the majority being mixed failures. The use of a bulk-fill flowable base material significantly increased the fracture strength of extracted root-filled teeth with MOD cavities; however it did not improve fracture patterns to more favorable ones. Investigating restorative techniques that may improve the longevity of root-filled premolar teeth restored with direct resin restorations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A new symmetry-based scoring method for posture assessment: evaluation of the effect of insoles with mineral derivatives.

    Science.gov (United States)

    Masse, M; Gaillardetz, C; Cron, C; Abribat, T

    2000-01-01

    There is a need for a validated rapid procedure for the evaluation of posture, defined as lateral balance/imbalance at the pelvic, shoulder, and neck levels. This would enable clinicians to determine the importance of symmetry in the pathophysiology of musculoskeletal disorders and to assess the efficacy of devices and treatments claiming to normalize or improve posture. In this investigation, the efficacy of such a device, a set of insoles with a hypothesized proprioceptive-like action, was evaluated through use of the described procedure. To develop a new scoring system to evaluate body posture on the basis of symmetry and to use this scoring system to investigate the efficacy of insoles containing a combination of mineral derivatives designed to balance posture through a neurophysiological effect. The posture score was based on the evaluation of 4 postural parameters: pelvic and shoulder lateral balance/imbalance, static shoulder rotation, and amplitude of head rotation. In the placebo-controlled study, 32 patients were tested in a double-blind fashion, either with placebo insoles or with insoles containing mineral derivatives. The same study was repeated in unblind conditions in 137 patients selected from 2 chiropractic clinics in an open-label protocol. A crossover placebo-controlled, double-blind study and a multicenter, large-scale, open-label study in patients selected from chiropractic clinics. A basal postural evaluation in 137 patients revealed that no patient had a perfect symmetry-ie, a perfectly or nearly perfectly balanced posture. The insoles with mineral derivatives induced a highly significant and similar improvement in the postural score in both the crossover double-blind study (32 patients; 56.7% improvement) and the open-label study (137 patients; 60.7% improvement, P postural imbalances according to the newly developed scoring method, and this method was successful in assessing the efficacy of insoles exerting a profound and immediate postural

  2. Have wet meadow restoration projects in the Southwestern U.S. been effective in restoring geomorphology, hydrology, soils, and plant species composition?

    Directory of Open Access Journals (Sweden)

    Ramstead Karissa M

    2012-09-01

    Full Text Available Abstract Background Wet meadows occur in numerous locations throughout the American Southwest, but in many cases have become heavily degraded. Among other things they have frequently been overgrazed and have had roads built through them, which have affected the hydrology of these wetland ecosystems. Because of the important hydrologic and ecological functions they are believed to perform, there is currently significant interest in wet meadow restoration. Several restoration projects have been completed recently or are underway in the region, sometimes at considerable expense and with minimal monitoring. The objective of this review was to evaluate the effects of wet meadow restoration projects in the southwestern United States on geomorphology, hydrology, soils and plant species composition. A secondary objective was to determine the effects of wet meadow restoration projects on wildlife. Methods Electronic databases, internet search engines, websites and personal contacts were used to find articles of relevance to this review. Articles were filtered by title, abstract and full text. Summary information for each of the articles remaining after the filtering process was compiled and used to assess the quality of the evidence presented using two different approaches. Results Our searches yielded 48 articles, of which 25 were published in peer-reviewed journals, 14 were monitoring or project reports, and 9 were published in conference proceedings or are unpublished theses or manuscripts. A total of 26 operational-scale restoration projects were identified. A wide range of restoration techniques were employed, ranging from small-scale manipulations of stream channels (e.g., riffle structures to large scale pond-and-plug projects. Other common restoration techniques included fencing to exclude livestock (and sometimes also native ungulates, other forms of grazing management, seeding, and transplanting seedlings. Most of the articles reported that

  3. Effectiveness of preoperative planning in the restoration of balance and view in ankylosing spondylitis

    NARCIS (Netherlands)

    Pigge, R.R.; Scheerder, F.J.; Smit, T.H.; Mullender, M.G.; van Royen, B.J.

    2008-01-01

    Object. The object of this study was to assess the effectiveness of preoperative planning in the restoration of balance and view angle in patients treated with lumbar osteotomy in ankylosing spondylitis (AS). Methods. The authors prospectively analyzed 8 patients with a thoracolumbar kyphotic

  4. Quantifying flooding effects on hardwood seedling survival and growth for bottomland restoration

    Science.gov (United States)

    John M. Kabrick; Daniel C. Dey; J.W. Van Sambeek; Mark V. Coggeshall; Douglass F. Jacobs

    2012-01-01

    Growing interest worldwide in bottomland hardwood restoration necessitates improved ecological understanding of flooding effects on forest tree seedlings using methodology that accurately reflects field conditions. We examined hardwood seedling survival and growth in an outdoor laboratory where the timing, depth, duration, and flow rate of flood water can be carefully...

  5. Autonomic nervous system function in chronic exogenous subclinical thyrotoxicosis and the effect of restoring euthyroidism

    NARCIS (Netherlands)

    Eustatia-Rutten, Carmen F. A.; Corssmit, Eleonora P. M.; Heemstra, Karen A.; Smit, Johannes W. A.; Schoemaker, Rik C.; Romijn, Johannes A.; Burggraaf, Jacobus

    2008-01-01

    Knowledge on the relationship between the autonomic nervous system and subclinical hyperthyroidism is mainly based upon cross-sectional studies in heterogeneous patient populations, and the effect of restoration to euthyroidism in subclinical hyperthyroidism has not been studied. We investigated the

  6. Using Species Distribution Models to Predict Potential Landscape Restoration Effects on Puma Conservation.

    Science.gov (United States)

    Angelieri, Cintia Camila Silva; Adams-Hosking, Christine; Ferraz, Katia Maria Paschoaletto Micchi de Barros; de Souza, Marcelo Pereira; McAlpine, Clive Alexander

    2016-01-01

    A mosaic of intact native and human-modified vegetation use can provide important habitat for top predators such as the puma (Puma concolor), avoiding negative effects on other species and ecological processes due to cascade trophic interactions. This study investigates the effects of restoration scenarios on the puma's habitat suitability in the most developed Brazilian region (São Paulo State). Species Distribution Models incorporating restoration scenarios were developed using the species' occurrence information to (1) map habitat suitability of pumas in São Paulo State, Southeast, Brazil; (2) test the relative contribution of environmental variables ecologically relevant to the species habitat suitability and (3) project the predicted habitat suitability to future native vegetation restoration scenarios. The Maximum Entropy algorithm was used (Test AUC of 0.84 ± 0.0228) based on seven environmental non-correlated variables and non-autocorrelated presence-only records (n = 342). The percentage of native vegetation (positive influence), elevation (positive influence) and density of roads (negative influence) were considered the most important environmental variables to the model. Model projections to restoration scenarios reflected the high positive relationship between pumas and native vegetation. These projections identified new high suitability areas for pumas (probability of presence >0.5) in highly deforested regions. High suitability areas were increased from 5.3% to 8.5% of the total State extension when the landscapes were restored for ≥ the minimum native vegetation cover rule (20%) established by the Brazilian Forest Code in private lands. This study highlights the importance of a landscape planning approach to improve the conservation outlook for pumas and other species, including not only the establishment and management of protected areas, but also the habitat restoration on private lands. Importantly, the results may inform environmental

  7. Effect of prophylactic polishing protocols on the surface roughness of esthetic restorative materials.

    Science.gov (United States)

    Neme, A L; Frazier, K B; Roeder, L B; Debner, T L

    2002-01-01

    Many polishing protocols have been evaluated in vitro for their effect on the surface roughness of restorative materials. These results have been useful in establishing protocols for in vivo application. However, limited research has focused on the subsequent care and maintenance of esthetic restorations following their placement. This investigation evaluated the effect of five polishing protocols that could be implemented at recall on the surface roughness of five direct esthetic restorative materials. Specimens (n=25) measuring 8 mm diameter x 3 mm thick were fabricated in an acrylic mold using five light-cured resin-based materials (hybrid composite, microfilled composite, packable composite, compomer and resin-modified glass ionomer). After photopolymerization, all specimens were polished with Sof-Lex Disks to produce an initial (baseline) surface finish. All specimens were then polished with one of five prophylactic protocols (Butler medium paste, Butler coarse paste, OneGloss, SuperBuff or OneGloss & SuperBuff). The average surface roughness of each treated specimen was determined from three measurements with a profilometer (Surface 1). Next, all specimens were brushed 60,000 times at 1.5 Hz using a brush-head force of 2 N on a Manly V-8 cross-brushing machine in a 50:50 (w/w) slurry of toothpaste and water. The surface roughness of each specimen was measured after brushing (Surface 2) followed by re-polishing with one of five protocols, then final surface roughness values were determined (Surface 3). The data were analyzed using repeated measures ANOVA. Significant differences (p=0.05) in surface roughness were observed among restorative materials and polishing protocols. The microfilled and hybrid resin composite yielded significantly rougher surfaces than the other three materials following tooth brushing. Prophylactic polishing protocols can be used to restore a smooth surface on resin-based esthetic restorative materials following simulated tooth

  8. Evaluating the effectiveness of restoring longitudinal connectivity for stream fish communities: towards a more holistic approach.

    Science.gov (United States)

    Tummers, Jeroen S; Hudson, Steve; Lucas, Martyn C

    2016-11-01

    A more holistic approach towards testing longitudinal connectivity restoration is needed in order to establish that intended ecological functions of such restoration are achieved. We illustrate the use of a multi-method scheme to evaluate the effectiveness of 'nature-like' connectivity restoration for stream fish communities in the River Deerness, NE England. Electric-fishing, capture-mark-recapture, PIT telemetry and radio-telemetry were used to measure fish community composition, dispersal, fishway efficiency and upstream migration respectively. For measuring passage and dispersal, our rationale was to evaluate a wide size range of strong swimmers (exemplified by brown trout Salmo trutta) and weak swimmers (exemplified by bullhead Cottus perifretum) in situ in the stream ecosystem. Radio-tracking of adult trout during the spawning migration showed that passage efficiency at each of five connectivity-restored sites was 81.3-100%. Unaltered (experimental control) structures on the migration route had a bottle-neck effect on upstream migration, especially during low flows. However, even during low flows, displaced PIT tagged juvenile trout (total n=153) exhibited a passage efficiency of 70.1-93.1% at two nature-like passes. In mark-recapture experiments juvenile brown trout and bullhead tagged (total n=5303) succeeded in dispersing upstream more often at most structures following obstacle modification, but not at the two control sites, based on a Laplace kernel modelling approach of observed dispersal distance and barrier traverses. Medium-term post-restoration data (2-3years) showed that the fish assemblage remained similar at five of six connectivity-restored sites and two control sites, but at one connectivity-restored headwater site previously inhabited by trout only, three native non-salmonid species colonized. We conclude that stream habitat reconnection should support free movement of a wide range of species and life stages, wherever retention of such

  9. Fifty years of symmetry operations

    International Nuclear Information System (INIS)

    Wigner, E.P.

    1978-01-01

    The author begins by discussing the application of symmetry principles in classical physics, which began 150 years ago. He then offers a few remarks on the essence of these principles and their role in the structure of physics; events, laws of nature, and invariance principles - kinematic and then dynamic - are treated. After this general discussion of the various types of symmetries, he considers the fundamental differences in their application in classical and quantum physics; the symmetry principles have greater effectiveness in quantum theory. After a few critical remarks of a general nature on the invariance principles, the author reviews the application of symmetry principles in various areas of quantum mechanics: atomic spectra, molecular physics, solid state physics, nuclear physics, and particle physics. He notes that the role of the different symmetries recognized to be approximate provide the most interesting conclusions

  10. The effect of topsoil removal in restored heathland on soil fauna, topsoil microstructure, and cellulose decomposition : implications for ecosystem restoration

    NARCIS (Netherlands)

    Frouz, Jan; Van Diggelen, Rudy; Pizl, Vaclav; Stary, Josef; Hanel, Ladislav; Tajovsky, Karel; Kalcik, Jiri

    2009-01-01

    Communities of soil macrofauna, oribatid mites, and nematodes as well as vegetation and soil chemistry were studied on twelve plots representing three replicates of the following treatments: agricultural meadow, heathland, and heathland restored either by partial or complete topsoil removal 15 years

  11. The effect of topsoil removal in restored heathland on soil fauna, topsoil microstructure, and cellulose decomposition: implications for ecosystem restoration

    Czech Academy of Sciences Publication Activity Database

    Frouz, Jan; van Diggelen, R.; Pižl, Václav; Starý, Josef; Háněl, Ladislav; Tajovský, Karel; Kalčík, Jiří

    2009-01-01

    Roč. 18, č. 14 (2009), s. 3963-3978 ISSN 0960-3115 Institutional research plan: CEZ:AV0Z60660521 Keywords : restoration * soil formation * oribatid mites Subject RIV: EH - Ecology, Behaviour Impact factor: 2.066, year: 2009

  12. Effects of CMS types and restorer alleles on plant performance in Plantago lanceolata L.: an indication for cost of restoration

    NARCIS (Netherlands)

    De Haan, A.A.; Hundscheid, M.P.J.; Van Hinsberg, A.

    1997-01-01

    In gynodioecious species, male steriles co-occur with hermaphrodites. Usually, the male sterile trait is maternally inherited, hence it is called Cytoplasmic Male Sterility (CMS). Nuclear loci restore male fertility in combination with their 'own' specific cytoplasmic types. In theory, two fitness

  13. Some symmetries in nuclei

    International Nuclear Information System (INIS)

    Henley, E.M.

    1981-09-01

    Internal and space-time symmetries are discussed in this group of lectures. The first of the lectures deals with an internal symmetry, or rather two related symmetries called charge independence and charge symmetry. The next two discuss space-time symmetries which also hold approximately, but are broken only by the weak forces; that is, these symmetries hold for both the hadronic and electromagnetic forces

  14. Restoring fish ecological quality in estuaries: Implication of interactive and cumulative effects among anthropogenic stressors.

    Science.gov (United States)

    Teichert, Nils; Borja, Angel; Chust, Guillem; Uriarte, Ainhize; Lepage, Mario

    2016-01-15

    Estuaries are subjected to multiple anthropogenic stressors, which have additive, antagonistic or synergistic effects. Current challenges include the use of large databases of biological monitoring surveys (e.g. the European Water Framework Directive) to help environmental managers prioritizing restoration measures. This study investigated the impact of nine stressor categories on the fish ecological status derived from 90 estuaries of the North East Atlantic countries. We used a random forest model to: 1) detect the dominant stressors and their non-linear effects; 2) evaluate the ecological benefits expected from reducing pressure from stressors; and 3) investigate the interactions among stressors. Results showed that largest restoration benefits were expected when mitigating water pollution and oxygen depletion. Non-additive effects represented half of pairwise interactions among stressors, and antagonisms were the most common. Dredged sediments, flow changes and oxygen depletion were predominantly implicated in non-additive interactions, whereas the remainder stressors often showed additive impacts. The prevalence of interactive impacts reflects a complex scenario for estuaries management; hence, we proposed a step-by-step restoration scheme focusing on the mitigation of stressors providing the maximum of restoration benefits under a multi-stress context. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. The effect of rebonding and liner type on microleakage of Class V amalgam restorations

    Directory of Open Access Journals (Sweden)

    Moosavi H.

    2008-10-01

    Full Text Available Background and Aim: Application of varnish and dentin bonding agents can effectively reduce microleakage under amalgam restorations. Also rebonding may show some effects on microleakage and its complications. The aim of this study was to evaluate the effect of liner/ adhesives on microleakage of Class V amalgam restoration with or without rebonding. Materials and Methods: In this in vitro study Class V cavities were prepared on sixty sound human maxillary premolars with the gingival floor 1mm below the CEJ. Cases were divided into six groups of ten teeth each. Specimens in group 1 and 2 were lined with Copalite and Scotchbond Multi-Purpose (SBMP respectively. In the third group (control no liner was applied. The teeth were then restored with spherical amalgam. Specimens in group 4 to 6 received the same treatments but after filling, the interfaces of restorations and teeth were etched with 37% phosphoric acid gel, rinsed and dried. Adhesive resin of SBMP was applied over amalgam and tooth margins and polymerized (rebonding. Specimens were thermocycled, exposed to dye and sectioned. Microleakage was graded (0-3 using a stereomicroscope at X40 magnification. Data were analyzed with Kruskal-Wallis, Mann-Whitney and Wilcoxon pair wise statistical tests. P<0.05 was considered as the limit of significance. Results: The groups lined with SBMP showed the lowest and the groups without liner the highest microleakage (p= 0.001. Significant difference was observed in microleakage mean rank of enamel and dentin margins (p=0.048. Rebonding with resin did not improve the seal (p> 0.05. Conclusion: Based on the results of this study, total etch adhesive system had significant effect on microleakage of Class V amalgam restorations especially in cervical margin. Rebonding did not show a significant effect on microleakage.

  16. Effectiveness of Plants and Vegetation in Erosion Control and Restoration

    NARCIS (Netherlands)

    Sandercock, P.; Hooke, J.; De Baets, S.; Poesen, J.; Meerkerk, A.; van Wesemael, B.; Cammeraat, L.H.; Hooke, J.; Sandercock, P.

    2017-01-01

    In this chapter the approaches and methods used to measure plant effectiveness in reducing runoff and erosion are explained and results presented for each of the major land units, hillslopes and channels. Evaluations of the properties of plants required are made to inform plant selection for

  17. (Small) Resonant non-Gaussianities: Signatures of a Discrete Shift Symmetry in the Effective Field Theory of Inflation

    Energy Technology Data Exchange (ETDEWEB)

    Behbahani, Siavosh R.; /SLAC /Stanford U., Phys. Dept. /Boston U.; Dymarsky, Anatoly; /Princeton, Inst. Advanced Study; Mirbabayi, Mehrdad; /New York U., CCPP /New York U.; Senatore, Leonardo; /Stanford U., Phys. Dept. /KIPAC, Menlo Park

    2012-06-06

    We apply the Effective Field Theory of Inflation to study the case where the continuous shift symmetry of the Goldstone boson {pi} is softly broken to a discrete subgroup. This case includes and generalizes recently proposed String Theory inspired models of Inflation based on Axion Monodromy. The models we study have the property that the 2-point function oscillates as a function of the wavenumber, leading to oscillations in the CMB power spectrum. The non-linear realization of time diffeomorphisms induces some self-interactions for the Goldstone boson that lead to a peculiar non-Gaussianity whose shape oscillates as a function of the wavenumber. We find that in the regime of validity of the effective theory, the oscillatory signal contained in the n-point correlation functions, with n > 2, is smaller than the one contained in the 2-point function, implying that the signature of oscillations, if ever detected, will be easier to find first in the 2-point function, and only then in the higher order correlation functions. Still the signal contained in higher-order correlation functions, that we study here in generality, could be detected at a subleading level, providing a very compelling consistency check for an approximate discrete shift symmetry being realized during inflation.

  18. Non-linear realizations of conformal symmetry and effective field theory for the pseudo-conformal universe

    International Nuclear Information System (INIS)

    Hinterbichler, Kurt; Joyce, Austin; Khoury, Justin

    2012-01-01

    The pseudo-conformal scenario is an alternative to inflation in which the early universe is described by an approximate conformal field theory on flat, Minkowski space. Some fields acquire a time-dependent expectation value, which breaks the flat space so(4,2) conformal algebra to its so(4,1) de Sitter subalgebra. As a result, weight-0 fields acquire a scale invariant spectrum of perturbations. The scenario is very general, and its essential features are determined by the symmetry breaking pattern, irrespective of the details of the underlying microphysics. In this paper, we apply the well-known coset technique to derive the most general effective lagrangian describing the Goldstone field and matter fields, consistent with the assumed symmetries. The resulting action captures the low energy dynamics of any pseudo-conformal realization, including the U(1)-invariant quartic model and the Galilean Genesis scenario. We also derive this lagrangian using an alternative method of curvature invariants, consisting of writing down geometric scalars in terms of the conformal mode. Using this general effective action, we compute the two-point function for the Goldstone and a fiducial weight-0 field, as well as some sample three-point functions involving these fields

  19. Symmetry and electromagnetism. Simetria y electromagnetismo

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes Cobas, L.E.; Font Hernandez, R.

    1993-01-01

    An analytical treatment of electrostatic and magnetostatic field symmetry, as a function of charge and current distribution symmetry, is proposed. The Newmann Principle, related to the cause-effect symmetry relation, is presented and applied to the characterization of simple configurations. (Author) 5 refs.

  20. Simulated wetland conservation-restoration effects on water quantity and quality at watershed scale.

    Science.gov (United States)

    Wang, Xixi; Shang, Shiyou; Qu, Zhongyi; Liu, Tingxi; Melesse, Assefa M; Yang, Wanhong

    2010-07-01

    Wetlands are one of the most important watershed microtopographic features that affect hydrologic processes (e.g., routing) and the fate and transport of constituents (e.g., sediment and nutrients). Efforts to conserve existing wetlands and/or to restore lost wetlands require that watershed-level effects of wetlands on water quantity and water quality be quantified. Because monitoring approaches are usually cost or logistics prohibitive at watershed scale, distributed watershed models such as the Soil and Water Assessment Tool (SWAT), enhanced by the hydrologic equivalent wetland (HEW) concept developed by Wang [Wang, X., Yang, W., Melesse, A.M., 2008. Using hydrologic equivalent wetland concept within SWAT to estimate streamflow in watersheds with numerous wetlands. Trans. ASABE 51 (1), 55-72.], can be a best resort. However, there is a serious lack of information about simulated effects using this kind of integrated modeling approach. The objective of this study was to use the HEW concept in SWAT to assess effects of wetland restoration within the Broughton's Creek watershed located in southwestern Manitoba, and of wetland conservation within the upper portion of the Otter Tail River watershed located in northwestern Minnesota. The results indicated that the HEW concept allows the nonlinear functional relations between watershed processes and wetland characteristics (e.g., size and morphology) to be accurately represented in the models. The loss of the first 10-20% of the wetlands in the Minnesota study area would drastically increase the peak discharge and loadings of sediment, total phosphorus (TP), and total nitrogen (TN). On the other hand, the justifiable reductions of the peak discharge and loadings of sediment, TP, and TN in the Manitoba study area may require that 50-80% of the lost wetlands be restored. Further, the comparison between the predicted restoration and conservation effects revealed that wetland conservation seems to deserve a higher priority

  1. Effect of dental restorative materials on total antioxidant capacity and calcium concentration of unstimulated saliva.

    Science.gov (United States)

    Ramezani, Gholam H; Moghadam, Mona-Momeni; Saghiri, Mohammad-Ali; Garcia-Godoy, Franklin; Asatourian, Armen; Aminsobhani, Mohsen; Scarbecz, Mark; Sheibani, Nader

    2017-01-01

    To evaluate the effect of dental amalgam and composite restorations on total antioxidant capacity (TAC) and calcium (Ca) ion concentration of unstimulated saliva. Forty-eight children aged 6-10 years selected and divided into three groups of sixteen (8 males, 8 females). In group A and B, samples consisted of two class II dental composite or amalgam restorations, while in group C samples were caries-free (control group). Unstimulated saliva from all samples was collected and TAC was measured by spectrophotometry using an adaptation of 2, 2'-azino-di-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) assay. The Ca ion level was estimated by an auto- analyzer. Data were analyzed with one- and two-way ANOVA test, at a p difference between groups ( p differences within and between groups ( p Gender is an effective factor in changes induced in oral cavity as females showed more emphatic reaction to dental filling materials than males. Patients who have dental restorations, especially dental composites, should pay more attention to their dental hygiene, because dental restorations can increase oxidative stress and decrease Ca ion level in saliva, which might jeopardize remineralization process of tooth structures after demineralization. Key words: Amalgam, caries, composite, saliva, total antioxidant capacity.

  2. Restorative effect of exogenous RNA on the intestinal crypts in mice after abdominal γ-irradiation

    International Nuclear Information System (INIS)

    Zeng Guiying; Han Shichen; Liu Aiping; Xie Xuejun; Zhou Yuankai

    1995-01-01

    The author's previous investigation revealed a restorative effect of exogenous nucleic acids on the intestinal crypt in mice after abdominal γ-irradiation. In the article, the factors influencing the restorative effect of exogenous RNA on the intestinal crypt in mice post-irradiation were studied. The results showed that: (a) RNAs from different sources all showed the crypt survival enhancement capability. (b) Bell-shaped curves correlating the crypt survival fraction and RNA doses were obtained, with the optimal doses for different routes of administration estimated. (c) Comparing the different routes of RNA administration, the intravenous injection seemed to be the most effective. (d) An exponential relationship between the crypt survival fraction and the post-irradiation time of RNA administration was found. The earlier the administration, the more effective it was. (e) Administration of RNA merely once within 6h after irradiation, the increases of crypt survival fraction was statistically significant when compared with that of the irradiated control

  3. Adverse effects of salivary contamination for adhesives in restorative dentistry. A literature review.

    Science.gov (United States)

    Nair, Pooja; Hickel, Reinhard; Ilie, Nicoleta

    2017-06-01

    To review and critically analyze the literature concerning the influence of salivary contamination on the bond quality of adhesives used in restorative materials by comparing and contrasting the different adhesive materials. A detailed search on PUBMED, Cochrane Library, Google Scholar and Web of Science was carried out to identify publications on salivary contamination and dental adhesive materials, from 1990-2017 (March) which resulted in a total of 6,202 web-identified publications. After screening titles/abstracts and de-duplicating, 54 publications were selected that matched the requirements for this review. The condition for selection was English literature concerning the effect of salivary contamination on the adhesives used in restorative dentistry. The obtained articles were systematically evaluated. Salivary contamination of adhesives during restorative procedures statistically (64.6%) showed an adverse effect on adhesives, occurring either at one or many stages of restoration. Methodological dissimilarities impeded the direct comparison of the selected studies. Nevertheless, the 2-step etch and rinse adhesives were relatively less vulnerable to salivary contamination than the others. 65% of the evaluated studies for decontamination achieved improved bonding when the contaminated surface was subjected to some kind of decontamination procedure. However, the duration and other specificities were not standard in all the evaluations and need further research to assess the course of action. It is necessary to do long term studies to evaluate the effectiveness of contaminated adhesive over time. Salivary contamination is a potential cause for poor bond quality of adhesive systems during restorative procedures and to provide a successful treatment, proper care must be taken to ensure the operating area is free from contamination. Understanding the properties of the materials and its constituents as well as considering measures to manage the potential

  4. Effects of valence nucleon orbits and charge symmetry breaking interaction on the Nolen-Schiffer anomaly of mirror nuclei

    International Nuclear Information System (INIS)

    Suzuki, T.; Sagawa, H.; Arima, A.

    1992-01-01

    Coulomb energy differences (Nolen-Schiffer anomalies) of mirror nuclei 17 O- 17 F and 41 Ca- 41 Sc are studied by using realistic Hartree-Fock and Woods-Saxon single-particle wave functions which are determined precisely through the analysis of the magnetic form factors of electron scattering. These single-particle wave functions are used to evaluate the Coulomb energy differences due to charge symmetry breaking forces, with new coupling constants determined by the analysis of the scattering lengths of pp and nn system which have been successfully applied to the Coulomb energy difference of 3 He- 3 H. We also evaluated the effects of the charge symmetry breaking forces using Hartree-Fock wave functions. Together with various other contributions, our calculated values of the Coulomb energy differences, which showed deviations of 3-9% from the experimental values in the previous analysis of Nolen and Schiffer, agree with the experimental values within 1% (2%) accuracy for A=17 (41). (orig.)

  5. Chiral symmetry and chiral-symmetry breaking

    International Nuclear Information System (INIS)

    Peskin, M.E.

    1982-12-01

    These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed

  6. Effect of Precuring Warming on Mechanical Properties of Restorative Composites

    Directory of Open Access Journals (Sweden)

    Kareem Nada

    2011-01-01

    Full Text Available To investigate the effect of prepolymerization warming on composites' mechanical properties, three composites were evaluated: Clearfil Majesty (CM (Kuraray, Z-100 (3M/ESPE, and Light-Core (LC (Bisco. Specimens were prepared from each composite at room temperature as control and 2 higher temperatures (37∘C and 54∘C to test surface hardness (SH, compressive strength (CS, and diametral tensile strength (DTS. Data were statistically analyzed using ANOVA and Fisher's LSD tests. Results revealed that prewarming CM and Z100 specimens significantly improved their SH mean values (P<0.05. Prewarming also improved mean CS values of Z100 specimens (P<0.05. Furthermore, DTS mean value of CM prepared at 52∘ was significantly higher than that of room temperature specimens (P<0.05. KHN, CS, and DTS mean values varied significantly among the three composites. In conclusion, Prewarming significantly enhanced surface hardness of 2 composites. Prewarming also improved bulk properties of the composites; however, this improvement was significant in only some of the tested materials.

  7. Effects of finishing/polishing techniques on microleakage of resin-modified glass ilonomer cement restorations.

    Science.gov (United States)

    Yap, Adrian U J; Yap, W Y; Yeo, Egwin J C; Tan, Jane W S; Ong, Debbie S B

    2003-01-01

    This study investigated the effect of finishing/polishing techniques on the microleakage of resin-modified glass ionomer restorations. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (FT [GC]) and Photac-Fil Quick (PF [3M-ESPE]) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with eight-fluted tungsten carbide burs. The teeth were then randomly divided into four groups and finishing/polishing was done with one of the following systems: (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Polishers (CS). The sample size for each material-finishing/polishing system combination was eight. After finishing/polishing, the teeth were stored in distilled water at 37 degrees C for one week. The root apices were then sealed with acrylic and two coats of varnish was applied 1 mm beyond the restoration margins. The teeth were subsequently subjected to dye penetration testing (0.5% basic fuchsin), sectioned and scored. Data was analyzed using Kruskal-Wallis and Mann-Whitney U tests at a significance level of 0.05. Results of statistical analysis were as follows: Enamel margins: PF-OGrestorations had significantly less enamel and dentin leakage than PF restorations when treated with OG. The effect of finishing/polishing techniques on microleakage was both tissue and material dependent.

  8. The effect of bleaching agents on the microhardness of dental aesthetic restorative materials.

    Science.gov (United States)

    Türker, S B; Biskin, T

    2002-07-01

    This study investigated the effects of three home bleaching agents on the microhardness of various dental aesthetic restorative materials. The restorative materials were: feldspatic porcelain, microfilled composite resin and light-cured modified glass-ionomer cement and the bleaching agents Nite-White (16% carbamide peroxide), Opalescence (10% carbamide peroxide and carbapol jel) and Rembrandt (10% carbamide peroxide jel). A total of 90 restorative material samples were prepared 1 cm diameter and 6 mm thick and kept in distilled water for 24 h before commencing bleaching which was carried out for 8 h day-1 for 4 weeks. Microhardness measurements were then made using a Tukon tester. Statistically significant differences with respect to unbleached controls were found only for the feldspatic porcelain and microfilled composite resins (P light cured modified glass-ionomer cement. For the composite resin, whereas Nite-White increased its microhardness, the other bleaching agents decreased it. There were no significant differences between the bleaching agents for any of the restorative materials.

  9. Dietary caffeine, performance and mood: enhancing and restorative effects after controlling for withdrawal reversal.

    Science.gov (United States)

    James, Jack E; Gregg, M Elizabeth; Kane, Marian; Harte, Frances

    2005-01-01

    This study aimed to determine whether sustained (i.e. dietary) use of caffeine has net effects on performance and mood compared with sustained abstinence, and whether dietary caffeine restores performance and mood adversely affected by sleep restriction. Participants (n = 96) alternated weekly between ingesting placebo and caffeine (1.75 mg/kg) three times daily for 4 consecutive weeks, while either rested or sleep restricted. Performance involved either a single task requiring sustained vigilance or a varied battery of brief psychomotor and cognitive tasks, and mood was assessed using the Profile of Mood States. Caffeine had no significant net enhancing effects for either performance or mood when participants were rested, and produced no net restorative effects when performance and mood were degraded by sleep restriction. Copyright 2005 S. Karger AG, Basel

  10. Restorative neuroscience

    DEFF Research Database (Denmark)

    Andres, Robert H; Meyer, Morten; Ducray, Angélique D

    2008-01-01

    There is increasing interest in the search for therapeutic options for diseases and injuries of the central nervous system (CNS), for which currently no effective treatment strategies are available. Replacement of damaged cells and restoration of function can be accomplished by transplantation of...

  11. Chiral symmetry and quark-antiquark pair creation in a strong color-electromagnetic field

    International Nuclear Information System (INIS)

    Suganuma, Hideo; Tatsumi, Toshitaka.

    1993-01-01

    We study the manifestation of chiral symmetry and q-q-bar pair creation in the presence of the external color-electromagnetic field, using the Nambu-Jona-Lasinio model. We derive the compact formulae of the effective potential, the Dyson equation for the dynamical quark mass and the q-q-bar pair creation rate in the covariantly constant color-electromagnetic field. Our results are compared with those in other approaches. The chiral-symmetry restoration takes place by a strong color-electric field, and the rapid reduction of the dynamical quark mass is found around the critical field strength, ε cr ≅4GeV/fm. Natural extension to the three-flavor case including s-quarks is also done. Around quarks or antiquarks, chiral symmetry would be restored by the sufficiently strong color-electric field, which may lead to the chiral bag picture of hadrons. For the early stage for ultrarelativistic heavy-ion collisions, the possibility of the chiral-symmetry restoration is indicated in the central region just after the collisions. (author)

  12. Astroparticle tests of Lorentz symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Jorge [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2016-07-01

    Lorentz symmetry is a cornerstone of modern physics. As the spacetime symmetry of special relativity, Lorentz invariance is a basic component of the standard model of particle physics and general relativity, which to date constitute our most successful descriptions of nature. Deviations from exact symmetry would radically change our view of the universe and current experiments allow us to test the validity of this assumption. In this talk, I describe effects of Lorentz violation in cosmic rays and gamma rays that can be studied in current observatories.

  13. Symmetries and nuclei

    International Nuclear Information System (INIS)

    Henley, E.M.

    1987-01-01

    Nuclei are very useful for testing symmetries, and for studies of symmetry breaking. This thesis is illustrated for two improper space-time transformations, parity and time-reversal and for one internal symmetry: charge symmetry and independence. Recent progress and present interest is reviewed. 23 refs., 8 figs., 2 tabs

  14. Effect of Static and Cyclic Loading on Ceramic Laminate Veneers Adhered to Teeth with and Without Aged Composite Restorations

    NARCIS (Netherlands)

    Gresnigt, Marco M. M.; Ozcan, Mutlu; Kalk, Warner; Galhano, Graziela

    2011-01-01

    Purpose: Existing composite restorations on teeth are often remade prior to the cementation of fixed dental prostheses. The aim of this study was to evaluate the effect of static and cyclic loading on ceramic laminate veneers adhered to aged resin composite restorations. Materials and Methods:

  15. Improved loop expansion for the effective potential of coupled boson-fermion systems at finite temperature and density

    International Nuclear Information System (INIS)

    Weiss, N.

    1983-01-01

    The effective potential V(phi) of a scalar field theory coupled to fermions is undefined near phi = 0 if the scalar field has a spontaneously broken symmetry. This shows up in a loop expansion as an imaginary part in V(phi) which persists to all temperatures and densities, even when the symmetry is restored. This paper presents a modification of the loop expansion which yields a real V(phi) whenever the one-loop fermion corrections restore the symmetry

  16. Effectiveness of an infiltrant on sealing of composite restoration margins with/without artificial caries.

    Science.gov (United States)

    Tulunoglu, Ozlem; Tulunoglu, Ibrahim Fevzi; Antonson, Sibel A; Campillo-Funollet, Marc; Antonson, Donald; Munoz-Viveros, Carlos

    2014-11-01

    The aim of this in vitro study was to evaluate the effectiveness of a resin infiltrant (ICON) on marginal sealing ability of class II resin restorations with/without-caries. Forty-eight noncarious human pre-molar teeth were embedded and MO and DO preparations of standard dimensions were prepared. The left side of dentin margins of the cavities were left nonbonded (UB) while the right side were bonded using total etch-bonding agent and all restored with a Nanohybrid composite. The teeth were thermocycled and half of the specimens in the UB and B groups were subjected to an artificial caries process. ICON was applied to caries and noncaries subgroups following the manufacturer's directions. Impressions were made at each step: after the restorations were completed, thermocycling, artificial caries procedures, and infiltrant application and the silicone tag lengths were measured with a stereomicroscope. The specimens were immersed in 0.5% basic fuchsine at 37° C for 24 hours, sectioned and microleakage was evaluated with a stereomicroscope. Selected samples and their replicas were assessed for marginal quality under a stereomicroscope and SEM. Statistical evaluation of the data were made using Kruskal-Wallis, Mann-Whitney U and Wilcoxon Sign Rank tests. While bonding application did not create a meaningful difference, the thermocycling and artificial caries significantly increased the gap length and microleakage (p < 0.05). ICON application was decreased the microleakage, created gap-free margins and closed the gaps which were previously occurred at the same cavities (p < 0.05). A resin infiltrant (ICON) application decreased the microleakage, created gap-free margins and closed the gaps, which previously occurred at the same cavities. Approximal application of resin infiltrant may increase the success of the class II composite restorations also reduced the risk of needing more complex restoration therapy.

  17. Spontaneous symmetry breaking in curved space-time

    International Nuclear Information System (INIS)

    Toms, D.J.

    1982-01-01

    An approach dealing with some of the complications which arise when studying spontaneous symmetry breaking beyond the tree-graph level in situations where the effective potential may not be used is discussed. These situations include quantum field theory on general curved backgrounds or in flat space-times with non-trivial topologies. Examples discussed are a twisted scalar field in S 1 xR 3 and instabilities in an expanding universe. From these it is seen that the topology and curvature of a space-time may affect the stability of the vacuum state. There can be critical length scales or times beyond which symmetries may be broken or restored in certain cases. These features are not present in Minkowski space-time and so would not show up in the usual types of early universe calculations. (U.K.)

  18. Broken symmetry phase transition in solid p-H 2, o-D 2 and HD: crystal field effects

    Science.gov (United States)

    Freiman, Yu. A.; Hemley, R. J.; Jezowski, A.; Tretyak, S. M.

    1999-04-01

    We report the effect of the crystal field (CF) on the broken symmetry phase transition (BSP) in solid parahydrogen, orthodeuterium, and hydrogen deuteride. The CF was calculated taking into account a distortion from the ideal HCP structure. We find that, in addition to the molecular field generated by the coupling terms in the intermolecular potential, the Hamiltonian of the system contains a crystal-field term, originating from single-molecular terms in the intermolecular potential. Ignoring the CF is the main cause of the systematic underestimation of the transition pressure, characteristic of published theories of the BSP transition. The distortion of the lattice that gives rise to the negative CF in response to the applied pressure is in accord with the general Le Chatelier-Braun principle.

  19. Clinical teaching in restorative dentistry and the variation between students' and supervisors' perceptions of its effectiveness.

    LENUS (Irish Health Repository)

    Polyzois, I

    2010-05-01

    To investigate if there was an agreement between the students and supervisors on the quality of clinical teaching in Restorative Dentistry in the Dublin Dental School and Hospital and to identify differences on how effective clinical teaching is perceived between three academic years. In addition it aimed to identify the existence of any similarities between students\\' and supervisors\\' perceptions of specific teaching behaviours that are most and least helpful in learning.

  20. Proposed best modeling practices for assessing the effects of ecosystem restoration on fish

    Science.gov (United States)

    Rose, Kenneth A; Sable, Shaye; DeAngelis, Donald L.; Yurek, Simeon; Trexler, Joel C.; Graf, William L.; Reed, Denise J.

    2015-01-01

    Large-scale aquatic ecosystem restoration is increasing and is often controversial because of the economic costs involved, with the focus of the controversies gravitating to the modeling of fish responses. We present a scheme for best practices in selecting, implementing, interpreting, and reporting of fish modeling designed to assess the effects of restoration actions on fish populations and aquatic food webs. Previous best practice schemes that tended to be more general are summarized, and they form the foundation for our scheme that is specifically tailored for fish and restoration. We then present a 31-step scheme, with supporting text and narrative for each step, which goes from understanding how the results will be used through post-auditing to ensure the approach is used effectively in subsequent applications. We also describe 13 concepts that need to be considered in parallel to these best practice steps. Examples of these concepts include: life cycles and strategies; variability and uncertainty; nonequilibrium theory; biological, temporal, and spatial scaling; explicit versus implicit representation of processes; and model validation. These concepts are often not considered or not explicitly stated and casual treatment of them leads to mis-communication and mis-understandings, which in turn, often underlie the resulting controversies. We illustrate a subset of these steps, and their associated concepts, using the three case studies of Glen Canyon Dam on the Colorado River, the wetlands of coastal Louisiana, and the Everglades. Use of our proposed scheme will require investment of additional time and effort (and dollars) to be done effectively. We argue that such an investment is well worth it and will more than pay back in the long run in effective and efficient restoration actions and likely avoided controversies and legal proceedings.

  1. Autonomic nervous system function in chronic exogenous subclinical thyrotoxicosis and the effect of restoring euthyroidism.

    Science.gov (United States)

    Eustatia-Rutten, Carmen F A; Corssmit, Eleonora P M; Heemstra, Karen A; Smit, Johannes W A; Schoemaker, Rik C; Romijn, Johannes A; Burggraaf, Jacobus

    2008-07-01

    Knowledge on the relationship between the autonomic nervous system and subclinical hyperthyroidism is mainly based upon cross-sectional studies in heterogeneous patient populations, and the effect of restoration to euthyroidism in subclinical hyperthyroidism has not been studied. We investigated the long-term effects of exogenous subclinical hyperthyroidism on the autonomic nervous system and the potential effects of restoration of euthyroidism. This was a prospective single-blinded, placebo-controlled, randomized trial. The study was performed at a university hospital. A total of 25 patients who were on more than 10-yr TSH suppressive therapy after thyroidectomy was examined. Patients were studied at baseline and subsequently randomized to a 6-month thyroid hormone substitution regimen to obtain either euthyroidism or maintenance of the subclinical hyperthyroid state. Urinary excretion of catecholamines and heart rate variability were measured. Baseline data of the subclinical hyperthyroidism patients were compared with data obtained in patients with hyperthyroidism and controls. Urinary excretion of norepinephrine and vanillylmandelic acid was higher in the subclinical hyperthyroidism patients compared with controls and lower compared with patients with overt hyperthyroidism. Heart rate variability was lower in patients with hyperthyroidism, intermediate in subclinical hyperthyroidism patients, and highest in the healthy controls. No differences were observed after restoration of euthyroidism. Long-term exogenous subclinical hyperthyroidism has effects on the autonomic nervous system measured by heart rate variability and urinary catecholamine excretion. No differences were observed after restoration to euthyroidism. This may indicate the occurrence of irreversible changes or adaptation during long-term exposure to excess thyroid hormone that is not remedied by 6-month euthyroidism.

  2. On the harmonic-type and linear-type confinement of a relativistic scalar particle yielded by Lorentz symmetry breaking effects

    Energy Technology Data Exchange (ETDEWEB)

    Bakke, K., E-mail: kbakke@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, Caixa Postal 5008, 58051-900, João Pessoa-PB (Brazil); Belich, H., E-mail: belichjr@gmail.com [Departamento de Física e Química, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Goiabeiras, 29060-900, Vitória, ES (Brazil)

    2016-10-15

    Based on the Standard Model Extension, we investigate relativistic quantum effects on a scalar particle in backgrounds of the Lorentz symmetry violation defined by a tensor field. We show that harmonic-type and linear-type confining potentials can stem from Lorentz symmetry breaking effects, and thus, relativistic bound state solutions can be achieved. We first analyse a possible scenario of the violation of the Lorentz symmetry that gives rise to a harmonic-type potential. In the following, we analyse another possible scenario of the breaking of the Lorentz symmetry that induces both harmonic-type and linear-type confining potentials. In this second case, we also show that not all values of the parameter associated with the intensity of the electric field are permitted in the search for polynomial solutions to the radial equation, where the possible values of this parameter are determined by the quantum numbers of the system and the parameters associated with the violation of the Lorentz symmetry.

  3. Symmetry, from Euclid to Pierre Curie

    International Nuclear Information System (INIS)

    Sivardiere, J.

    1997-01-01

    A historical review of the principles of symmetry is presented, starting with Egyptian pavements and Euclid regular polyhedrons, 2 and 3 dimensional paving studies with Kepler in the 17. century, modern crystallography with the constant angle law and the rational truncations law in the 18. century, the identification of the various crystal symmetries (19. century), the discovery of liquid crystals, the relations between the symmetry and the physical and optical properties of systems, molecules, etc.. Finally, P. Curie has determined the general principle of symmetry, linking symmetry and its effects

  4. Landscape and vegetation effects on avian reproduction on bottomland forest restorations

    Science.gov (United States)

    Twedt, Daniel J.; Somershoe, Scott G.; Hazler, Kirsten R.; Cooper, Robert J.

    2010-01-01

    Forest restoration has been undertaken on >200,000 ha of agricultural land in the Mississippi Alluvial Valley, USA, during the past few decades. Decisions on where and how to restore bottomland forests are complex and dependent upon landowner objectives, but for conservation of silvicolous (forest-dwelling) birds, ecologists have espoused restoration through planting a diverse mix of densely spaced seedlings that includes fast-growing species. Application of this planting strategy on agricultural tracts that are adjacent to extant forest or within landscapes that are predominately forested has been advocated to increase forest area and enhance forested landscapes, thereby benefiting area-sensitive, silvicolous birds. We measured support for these hypothesized benefits through assessments of densities of breeding birds and reproductive success of 9 species on 36 bottomland forest restoration sites. Densities of thamnic (shrub-scrub dwelling) and silvicolous birds, such as yellow-breasted chat (Icteria virens), indigo bunting (Passerina cyanea), and white-eyed vireo (Vireo griseus) were positively associated with 1) taller trees, 2) greater stem densities, and 3) a greater proportion of forest within the landscape, whereas densities of birds associated with grasslands, such as dickcissel (Spiza americana) and red-winged blackbird (Agelaius phoeniceus), were negatively associated with these variables. Vegetation structure, habitat edge, and temporal effects had greater influence on nest success than did landscape effects. Taller trees, increased density of woody stems, greater vegetation density, and more forest within the landscape were often associated with greater nest success. Nest success of grassland birds was positively related to distance from forest edge but, for thamnic birds, success was greater near edges. Moreover, nest success and estimated fecundity of thamnic species suggested their populations are self-sustaining on forest restoration sites, whereas

  5. Mapping hemispheric symmetries, relative asymmetries, and absolute asymmetries underlying the auditory laterality effect.

    Science.gov (United States)

    Westerhausen, René; Kompus, Kristiina; Hugdahl, Kenneth

    2014-01-01

    listening engages a bihemispheric cortical network, showing a symmetrical and mostly leftward asymmetrical pattern. The here obtained functional (a)symmetry map might serve as a basis for future studies which - by studying the relevance of the here identified regions - clarify the relationship between behavioral laterality measures and hemispheric asymmetry. © 2013 Elsevier Inc. All rights reserved.

  6. Effect of potential barrier growth of auto-localized excitons decay on radiation defects in AHC at low lattice symmetry

    International Nuclear Information System (INIS)

    Shunkeev, K.; Sagimbaeva, Sh.; Shunkeev, S.

    2007-01-01

    Effect of auto-localized excitons (ALE) luminescence strengthening is conditioned by two mechanisms: either decrease of potential barrier divided of quasi-free states and auto-localized states or decrease of emission-less channel effectiveness of exciton decay on primary radiation defects. In considered range (80 K) all excitons are only in auto-localized state. Therefore a realization of the first mechanism is improbable, For instant, in KI crystal at 80-100 K luminescence of free exciton is completely putting out, and ALE luminescence has maximal intensity. It is known that in the temperature range when ALE luminescence putting out is beginning an effectiveness of radiation defects is beginning to grow. This effect is related with predominating at that time emission-less exciton decay on radiation defects (F-H pairs). Experimentally by luminescence spectroscopy method activation energy of temperature putting out of ALE in AHC under uniaxial deformation. It is revealed, that increase of activation energy value has observed in a number of crystals: KBr→NaCl→KI→Na Br→CsBr→RbI. It is concluded, that effect of ALE intensity building-up and decrease of effectiveness of radiation defect formation are interpreted by growth of potential barrier of ALE decay into radiation defects under low symmetry of AHC lattice of low-temperature uniaxial deformation

  7. The symmetry of man.

    Science.gov (United States)

    Ermolenko, Alexander E; Perepada, Elena A

    2007-01-01

    The paper contains a description of basic regularities in the manifestation of symmetry of human structural organization and its ontogenetic and phylogenetic development. A concept of macrobiocrystalloid with inherent complex symmetry is proposed for the description of the human organism in its integrity. The symmetry can be characterized as two-plane radial (quadrilateral), where the planar symmetry is predominant while the layout of organs of radial symmetry is subordinated to it. Out of the two planes of symmetry (sagittal and horizontal), the sagittal plane is predominant. The symmetry of the chromosome, of the embrio at the early stages of cell cleavage as well as of some organs and systems in their phylogenetic development is described. An hypothesis is postulated that the two-plane symmetry is formed by two mechanisms: a) the impact of morphogenetic fields of the whole crystalloid organism during embriogenesis and, b) genetic mechanisms of the development of chromosomes having two-plane symmetry.

  8. Evaluation of effects of ionizing radiation on the titanium used in dental restorations

    International Nuclear Information System (INIS)

    Maio, Mireia Florencio; Santos, Adimir dos; Fernandes, Marco A.R.

    2009-01-01

    The purpose of this work consisted of quantitative studies of the effects caused by ionizing radiation on titanium, a material used in dental restorations. Titanium is used to mitigate the deleterious effects of radiotherapy when patients with tumors in head and neck, seen when the teeth are restored within in the field of radiation. Samples were submitted to X-radiation beams from 6 and 10 Mega - Volt (MV) from a linear accelerator, VARIAN 2100C model. The samples were analyzed by X-ray fluorescence techniques to compare the chemical composition before and after the irradiation. Sample dose measurements were performed employing Geiger-Mueller detectors and the ionization chamber in order to verify any residual radiation in the samples. The samples were also analyzed by gamma spectrometry by a HPGe detector. These tests were performed to determine small changes in the composition in the samples due to the radiation interaction. The results of this study may encourage the development of new research for alternative materials in dental restorations that can contribute to improve the quality of life of those patients with tumors of the mouth. (author)

  9. Effect of Different Prophylaxis Methods on Microleakage of Microfilled Composite Restorations

    Directory of Open Access Journals (Sweden)

    Soodabeh Kimyai

    2012-04-01

    Full Text Available Background and aims. This study was aimed at evaluating the effect of different prophylaxis methods on microleakage of microfilled composite restorations. Materials and methods. In this in vitro study, class V cavities were prepared on buccal surfaces of 84 bovine teeth. The teeth were restored with Tetric N-Bond adhesive and Heliomolar composite resin. Subsequent to a thermocycling procedure and three months of storage in distilled water, the teeth were randomly assigned to four groups (n=21: (1 prophylaxis with a rubber cup and pumice; (2 prophylaxis with a brush and pumice; (3 prophylaxis with air/powder polishing device; and (4 no prophylaxis (the control group. Then the teeth were immersed in 2% basic fuchsin for 24 hours and sectioned for microleakage evaluation under a stereomicroscope. Data were analyzed using Kruskal-Wallis and Wilcoxon Signed Ranks tests. Statistical significance was defined at p<0.05. Results. There were no statistically significant differences in occlusal and gingival microleakage between the groups (p=0.996 and p=0.860, respectively. In all the groups gingival margins exhibited significantly higher microleakage values compared to occlusal margins (p<0.0005. Conclusion. Prophylaxis methods had no adverse effect on marginal leakage of microfilled composite resin restorations.

  10. Evaluation of effects of ionizing radiation on the glass ionomer used in dental restorations

    International Nuclear Information System (INIS)

    Maio, F.M.; Santos, A.; Fernandes, M.A.R.

    2009-01-01

    The purpose of this work consisted of quantitative studies of the effects caused by ionizing radiation on glass ionomer, a material used in dental restorations. Glass ionomer is used to mitigate the deleterious effects of radiotherapy when patients with tumors in head and neck, seen when the teeth are restored within in the field of radiation. Samples were submitted to X-radiation beams from 6 MV from a linear accelerator, VARIAN 2100C model. The samples were analyzed by X-ray fluorescence techniques to compare the chemical composition before and after the irradiation. Sample dose measurements were performed employing Geiger-Mueller detectors and the ionization chamber in order to verify any residual radiation in the samples. The samples were also analyzed by gamma spectrometry by a HPGe detector. These tests were performed to determine small changes in the composition in the samples due to the radiation interaction. The results of this study may encourage the development of new research for alternative materials in dental restorations that can contribute to improve the quality of life of those patients with tumors of the mouth. (author)

  11. Evaluation of effects of ionizing radiation on materials used in dental restorations

    International Nuclear Information System (INIS)

    Maio, Mireia Florencio

    2009-01-01

    This work consisted of quantitative studies of the effects caused by ionizing radiation on materials used in dental restorations (Titanium, Amalgam, Resin Composite and Glass Ionomer) aiming the deleterious effects of radiotherapy when patients with tumors in head and neck, arising when the teeth are restored within in the field of radiation. Samples were submitted to X-ray beams of 6 MV from a linear accelerator, VARIAN 2100C model. The samples were analyzed by X-ray fluorescence techniques to compare the chemical composition before and after the irradiation. The sample were submitted to Geiger-Mueller detectors and the ionization chambers in order to verify any residual radiation in the samples. The samples were also analyzed by gamma spectrometry by a Germanium detector. These tests were performed to determine small changes in the composition in the samples due to the radiation interaction. The results of this study may encourage the development of new research for alternative materials in dental restorations that can contribute to improve the quality of life of those patients with tumors of the mouth. (author)

  12. Cumulative effects of restoration efforts on ecological characteristics of an open water area within the Upper Mississippi River

    Science.gov (United States)

    Gray, B.R.; Shi, W.; Houser, J.N.; Rogala, J.T.; Guan, Z.; Cochran-Biederman, J. L.

    2011-01-01

    Ecological restoration efforts in large rivers generally aim to ameliorate ecological effects associated with large-scale modification of those rivers. This study examined whether the effects of restoration efforts-specifically those of island construction-within a largely open water restoration area of the Upper Mississippi River (UMR) might be seen at the spatial scale of that 3476ha area. The cumulative effects of island construction, when observed over multiple years, were postulated to have made the restoration area increasingly similar to a positive reference area (a proximate area comprising contiguous backwater areas) and increasingly different from two negative reference areas. The negative reference areas represented the Mississippi River main channel in an area proximate to the restoration area and an open water area in a related Mississippi River reach that has seen relatively little restoration effort. Inferences on the effects of restoration were made by comparing constrained and unconstrained models of summer chlorophyll a (CHL), summer inorganic suspended solids (ISS) and counts of benthic mayfly larvae. Constrained models forced trends in means or in both means and sampling variances to become, over time, increasingly similar to those in the positive reference area and increasingly dissimilar to those in the negative reference areas. Trends were estimated over 12- (mayflies) or 14-year sampling periods, and were evaluated using model information criteria. Based on these methods, restoration effects were observed for CHL and mayflies while evidence in favour of restoration effects on ISS was equivocal. These findings suggest that the cumulative effects of island building at relatively large spatial scales within large rivers may be estimated using data from large-scale surveillance monitoring programs. Published in 2010 by John Wiley & Sons, Ltd.

  13. Interfacial symmetry of Co–Alq{sub 3}–Co hybrid structures for effective spin filtering

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Tu-Ngoc [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC (China); Lai, Yu-Ling; Chen, Chih-Han [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan, ROC (China); Chen, Po-Hung [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan, ROC (China); Wei, Der-Hsin; Lin, Hong-Ji; Chen, C.T. [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan, ROC (China); Sheu, Jeng-Tzong, E-mail: jtsheu@faculty.nctu.edu.tw [Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan, ROC (China); Hsu, Yao-Jane, E-mail: yjhsu@nsrrc.org.tw [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan, ROC (China); Institute of Electro-Optical Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC (China)

    2015-11-01

    Graphical abstract: - Highlights: • The spin interface at Alq{sub 3}/Co and Co/Alq{sub 3} contacts was examined. • An interfacial symmetry was determined at Co–Alq{sub 3}–Co interfaces. • Spin-polarized N orbitals are induced within the Co atop Alq{sub 3} hybridized interface. • The spin-filter role at the top contact interface of Alq{sub 3}/Co is proved. • Effective spin-filtering at Co–Alq{sub 3}–Co contacts was elucidated. - Abstract: Understanding the interfacial behavior at FM-OSC-FM hybrid structures for both the bottom contact (Alq{sub 3} adsorption on Co, Co/Alq{sub 3}) and the top contact (Co atop Alq{sub 3}, Alq{sub 3}/Co) is crucial for efficient spin filtering with transport of spin-polarized charge carriers through these interfaces. X-ray photoelectron spectroscopy (XPS) spectra indicate a symmetry of charge transfer from Co to Alq{sub 3} and the corresponding orbital hybridization to a certain extent at both contacts. The alignment of energy levels at both Alq{sub 3}/Co and Co/Alq{sub 3} heterostructures is depicted with ultraviolet photoelectron spectroscopy (UPS). Through magnetic images acquired with a X-ray photoemission electron microscope (XPEEM), the strong hybridization of the top contact presents no micromagnetic domain but still shows magnetic coupling, to some extent, to the bottom contact in the Co–Alq{sub 3}–Co trilayer structure. Measurements of X-ray magnetic circular dichroism (XMCD) demonstrate the induced spin-polarization of non-magnetic Alq{sub 3} at both contacts, proving Alq{sub 3} a unique and promising organic material for spin filtering in OSV.

  14. Regional effects of vegetation restoration on water yield across the Loess Plateau, China

    Directory of Open Access Journals (Sweden)

    X. M. Feng

    2012-08-01

    Full Text Available The general relationships between vegetation and water yield under different climatic regimes are well established at a small watershed scale in the past century. However, applications of these basic theories to evaluate the regional effects of land cover change on water resources remain challenging due to the complex interactions of vegetation and climatic variability and hydrologic processes at the large scale. The objective of this study was to explore ways to examine the spatial and temporal effects of a large ecological restoration project on water yield across the Loess Plateau region in northern China. We estimated annual water yield as the difference between precipitation input and modelled actual evapotranspiration (ET output. We constructed a monthly ET model using published ET data derived from eddy flux measurements and watershed streamflow data. We validated the ET models at a watershed and regional levels. The model was then applied to examine regional water yield under land cover change and climatic variability during the implementation of the Grain-for-Green (GFG project during 1999–2007. We found that water yield in 38% of the Loess Plateau area might have decreased (1–48 mm per year as a result of land cover change alone. However, combined with climatic variability, 37% of the study area might have seen a decrease in water yield with a range of 1–54 mm per year, and 35% of the study area might have seen an increase with a range of 1–10 mm per year. Across the study region, climate variability masked or strengthened the water yield response to vegetation restoration. The absolute annual water yield change due to vegetation restoration varied with precipitation regimes with the highest in wet years, but the relative water yield changes were most pronounced in dry years. We concluded that the effects of land cover change associated with ecological restoration varied greatly over time and space and were strongly influenced

  15. Effect of CO2 laser on root caries inhibition around composite restorations: an in vitro study.

    Science.gov (United States)

    de Melo, Jociana Bandeira; Hanashiro, Fernando Seishim; Steagall, Washington; Turbino, Miriam Lacalle; Nobre-dos-Santos, Marinês; Youssef, Michel Nicolau; de Souza-Zaroni, Wanessa Christine

    2014-03-01

    The aim of the present study was to investigate the in vitro effect of CO2 laser on the inhibition of root surface demineralization around composite resin restorations. For this purpose, 30 blocks obtained from human molar roots were divided into three groups: group 1 (negative control), cavity prepared with cylindrical diamond bur + acid etching + adhesive + composite resin restoration; group 2, cavity prepared with cylindrical diamond bur + CO2 laser (5.0 J/cm(2)) + acid etching + adhesive + composite resin; and group 3, cavity prepared with cylindrical diamond bur + CO2 laser (6.0 J/cm(2)) + acid etching + adhesive + composite resin. After this procedure, the blocks were submitted to thermal and pH cycling. Root surface demineralization around the restorations was measured by microhardness analysis. The hardness results of the longitudinally sectioned root surface were converted into percentage of mineral volume, which was used to calculate the mineral loss delta Z (ΔZ). The percentage of mineral volume, ΔZ, and the percentage of demineralization inhibition of the groups were statistically analyzed by using analysis of variance and Tukey-Kramer test. The percentage of mineral volume was higher in the irradiated groups up to 80 μm deep. The ΔZ was significantly lower in the irradiated groups than in the control group. The percentage of reduction in demineralization ranged from 19.73 to 29.21 in position 1 (50 μm), and from 24.76 to 26.73 in position 2 (100 μm), when using 6 and 5 J/cm(2), respectively. The CO2 laser was effective in inhibiting root demineralization around composite resin restorations.

  16. Structure of the vacuum in the color dielectric model: confinement and chiral symmetry

    International Nuclear Information System (INIS)

    Mazzolo, A.

    1992-01-01

    Two of the most important properties of Quantum Chromodynamic (QCD), spontaneous symmetry breaking of the vacuum and quark confinement at low energy, are first presented. Some important effective models for hadronic physics are then described. Putting QCD on the lattice and using the block-spin method, the color-dielectric model effective Lagrangian is obtained. The structure of the vacuum and the behaviour of uniform quark matter at high intensity are investigated in this model. Its original formulation is extended to handle chiral symmetry (by use of sigma model) and to include negative energy orbitals. At high baryonic density, the model describes the two phase transitions which are expected in QCD: deconfinement of quarks and chiral symmetry restoration. Finally, a heavy meson composed by a charmed quark anti-quark pair, is constructed, and the valence quarks confinement and the vacuum structure around them are studied

  17. The effect of urban growth on landscape-scale restoration for a fire-dependent songbird.

    Science.gov (United States)

    Pickens, Bradley A; Marcus, Jeffrey F; Carpenter, John P; Anderson, Scott; Taillie, Paul J; Collazo, Jaime A

    2017-04-15

    A landscape-scale perspective on restoration ecology has been advocated, but few studies have informed restoration with landscape metrics or addressed broad-scale threats. Threats such as urban growth may affect restoration effectiveness in a landscape context. Here, we studied longleaf pine savanna in the rapidly urbanizing southeastern United States where a habitat-specialist bird, Bachman's sparrow (Peucaea aestivalis), is closely associated with savanna vegetation structure and frequent fire. Our objectives were to construct a species distribution model for Bachman's sparrow, determine the relationship between fire and urbanization, quantify the urban growth effect (2010-2090), identify potential restoration areas, and determine the interaction between restoration potential and urban growth by 2050. Number of patches, patch size, and isolation metrics were used to evaluate scenarios. The species distribution model was 88% accurate and emphasized multiscale canopy cover characteristics, fire, and percent habitat. Fires were less common urban areas, and this fire suppression effect exacerbated urban growth effects. For restoration scenarios, canopy cover reduction by 30% resulted in nearly double the amount of habitat compared to the prescribed fire scenario; canopy cover reduction resulted in larger patch sizes and less patch isolation compared to current conditions. The effect of urban growth on restoration scenarios was unequal. Seventy-four percent of restoration areas from the prescribed fire scenario overlapped with projected urban growth, whereas the canopy cover reduction scenario only overlapped by 9%. We emphasize the benefits of simultaneously considering the effects of urban growth and landscape-scale restoration potential to promote a landscape with greater patch sizes and less isolation. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. The Immediate Effect of a Textured Insole in Nonparetic Lower Limb Symmetry of Weight Bearing and Gait Parameters in Patients with Chronic Stroke

    Directory of Open Access Journals (Sweden)

    Mehdi Hassan Abadi

    2016-04-01

    Conclusion The current study showed that obligatory use of affected limb side could improve symmetry of weight bearing in walking and standing position of patients with chronic stroke by overcoming the phenomenon of learned lack of using and correcting the failure of sending sensory signals to centers of movement controls. The results of this study showed that unilateral use of textured insole with shore A-80 in the unaffected side could immediately improve weight bearing symmetry and step length symmetry in patients with hemiparesis, but it has no effect on their walking speed and step length. Using insole with A-60 hardness did not significantly change any variables of tests. Considering the results of this study, these insoles can be used in balance exercises and walking of hemiparetic patients.

  19. Experimental effects of dynamics and thermodynamics in nuclear reactions on the symmetry energy as seen by the CHIMERA 4 π detector

    Energy Technology Data Exchange (ETDEWEB)

    De Filippo, E.; Pagano, A. [INFN, Catania (Italy)

    2014-02-15

    Heavy-ion collisions have been widely used in the last decade to constrain the parameterizations of the symmetry energy term of the nuclear equation of state (EOS) for asymmetric nuclear matter as a function of baryonic density. In the Fermi energy domain one is faced with variations of the density within a narrow range of values around the saturation density ρ{sub 0}=0.16 fm{sup -3} down towards sub-saturation densities. The experimental observables which are sensitive to the symmetry energy are constructed starting from the detected light particles, clusters and heavy fragments that, in heavy-ion collisions, are generally produced by different emission mechanisms at different stages and time scales of the reaction. In this review the effects of dynamics and thermodynamics on the symmetry energy in nuclear reactions are discussed and characterized using an overview of the data taken so far with the CHIMERA multi detector array. (orig.)

  20. The effect of rebonding on microleakage of class V aesthetic restorations.

    Science.gov (United States)

    Erhardt, Maria Carolina Guilherme; Magalhães, Cláudia Silami; Serra, Mônica Campos

    2002-01-01

    This in vitro study evaluated the effect of rebonding on microleakage of a resin composite, a condensable resin and two polyacid-modified resin composite restorations. Standardized cylindrical Class V dentin cavities were prepared on the buccal root surfaces of 240 extracted bovine incisive teeth. The prepared teeth were randomly assigned to four groups of 60 teeth and restored with the following restorative systems: I--(ZS) Z100/Scotchbond Multi-Purpose Plus; II--(SS) Solitaire/Solid Bond; III--(FS) Freedom/Stae; IV--(FSB) F200/Single Bond. Thirty teeth of each group were rebonded with a low-viscosity resin (Fortify/BISCO), according to the manufacturer's instructions. The remaining teeth received no treatment. All teeth were thermocycled for 5,000 cycles and brushed by hand three times a day for 10 days using a toothbrush and a slurry of dentifrice and water. Specimens were stained in a 2% methylene blue solution and longitudinally sectioned with diamond disks. Microleakage was scored on a scale of 0 to 3. The Kruskal-Wallis test showed statistically significant differences among the groups (h=156.54; alpha<0.05). Pairwise comparison by means of the least significant difference showed that (SS) and (FS) with or without rebonding were not statistically different from each other. These groups showed the highest microleakage differences from (ZS) and (FSB) with or without rebonding. (ZS) with rebonding showed the lowest microleakage that was not statistically different from (ZS) without rebonding and (FSB) with rebonding.

  1. Effects of gamma rays on a restored painting from the XVIIth century

    International Nuclear Information System (INIS)

    Rizzo, M.M.; Machado, L.D.B.; Borrely, S.I.; Sampa, M.H.O.; Rela, P.R.; Farah, J.P.S.; Schumacher, R.I.

    2002-01-01

    The subject of this study is a Peruvian painting from the 17th century, which has been recently restored and then contaminated by mould. It received different unsuccessful treatments. Therefore, radiation process was suggested as an alternative once it is an effective technology for decontamination and conservation purposes. The aim of this study is to investigate the influence of irradiation process on the original painting and on the products used in the restoration process. These products were irradiated with 60 Co gamma rays applying doses in the range of 6-25 kGy. The polymeric materials were characterized by thermal analysis techniques before and after irradiation. The colour of the pigments irradiated and non-irradiated were compared by spectrophotometric analysis. Small samples removed of the original painting were also irradiated and investigated. The results obtained until now allowed concluding that the irradiation with the appropriated dose of 6.0 kGy, according to the literature, will not damage the restored painting

  2. A biomathematical model of the restoring effects of caffeine on cognitive performance during sleep deprivation.

    Science.gov (United States)

    Ramakrishnan, Sridhar; Rajaraman, Srinivasan; Laxminarayan, Srinivas; Wesensten, Nancy J; Kamimori, Gary H; Balkin, Thomas J; Reifman, Jaques

    2013-02-21

    While caffeine is widely used as a countermeasure to sleep loss, mathematical models are lacking. Develop a biomathematical model for the performance-restoring effects of caffeine in sleep-deprived subjects. We hypothesized that caffeine has a multiplicative effect on performance during sleep loss. Accordingly, we first used a phenomenological two-process model of sleep regulation to estimate performance in the absence of caffeine, and then multiplied a caffeine-effect factor, which relates the pharmacokinetic-pharmacodynamic effects through the Hill equation, to estimate the performance-restoring effects of caffeine. We validated the model on psychomotor vigilance test data from two studies involving 12 subjects each: (1) single caffeine dose of 600mg after 64.5h of wakefulness and (2) repeated doses of 200mg after 20, 22, and 24h of wakefulness. Individualized caffeine models produced overall errors that were 19% and 42% lower than their population-average counterparts for the two studies. Had we not accounted for the effects of caffeine, the individualized model errors would have been 117% and 201% larger, respectively. The presented model captured the performance-enhancing effects of caffeine for most subjects in the single- and repeated-dose studies, suggesting that the proposed multiplicative factor is a feasible solution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. The effect of different drinks on the color stability of different restorative materials after one month

    Directory of Open Access Journals (Sweden)

    Neslihan Tekçe

    2015-11-01

    Full Text Available Objectives The aim of this study was to evaluate the effect of three different drinks on the color parameters of four different restorative materials. Materials and Methods Three different composites (Filtek Ultimate Universal Restorative, Filtek Ultimate Flowable, and Filtek Silorane, 3M ESPE and a polyacid-modified composite resin material (Dyract XP, Dentsply DeTrey GmbH were evaluated. Eighty-four disc-shaped specimens of 8 mm in diameter and 2 mm in thickness were prepared (n = 21 each. Color coordinates (L*a*b*, ΔL*, Δa*, Δb*, and ΔE* were measured using a VİTA Easyshade Compact (VİTA Zahnfabrik after 24 hr of storage (baseline and after 30 day of storage in three different beverages of black tea, Coca cola, or water (control (n = 7. In each beverage, the specimens were stored three times a day, one hr each, for 30 day. The color changes (ΔE were calculated and were analyzed by Kruskal-Wallis and Dunn multiple comparison test. Results The color difference (ΔE* of the resin materials ranged between 1.31 and 15.28 after 30 day of immersion in the staining solutions. Dyract XP in Coca cola (15.28 ± 2.61 and black tea (12.22 ± 2.73 showed the highest mean ΔE* value after 30 day, followed by Filtek Ultimate Universal Restorative (5.99 ± 1.25 and Filtek Ultimate Flowable (4.71 ± 1.40 in black tea (p < 0.05. Conclusions The compomers displayed unacceptable color changes at the end of 30 day in all beverages. Among resin composites, the silorane based composite exhibited relatively good color stability than the others. Filtek Ultimate Universal Restorative and Filtek Flowable showed similar color changes in all beverages.

  4. Restoration of Tidal Flow to Impounded Salt Marsh Exerts Mixed Effect on Leaf Litter Decomposition

    Science.gov (United States)

    Henry, B. A.; Schade, J. D.; Foreman, K.

    2015-12-01

    Salt marsh impoundments (e.g. roads, levees) disconnect marshes from ocean tides, which impairs ecosystem services and often promotes invasive species. Numerous restoration projects now focus on removing impoundments. Leaf litter decomposition is a central process in salt marsh carbon and nutrient cycles, and this study investigated the extent to which marsh restoration alters litter decomposition rates. We considered three environmental factors that can potentially change during restoration: salinity, tidal regime, and dominant plant species. A one-month field experiment (Cape Cod, MA) measured decay of litter bags in impounded, restored, and natural marshes under ambient conditions. A two-week lab experiment measured litter decay in controlled incubations under experimental treatments for salinity (1ppt and 30 ppt), tidal regime (inundated and 12 hr wet-dry cycles), and plant species (native Spartina alterniflora and invasive Phragmites australis). S. alterniflora decomposed faster in situ than P. australis (14±1.0% mass loss versus 0.74±0.69%). Corroborating this difference in decomposition, S. alterniflora supported greater microbial respiration during lab incubation, measured as CO2 flux from leaf litter and biological oxygen demand of water containing leached organic matter (OM). However, nutrient analysis of plant tissue and leached OM show P. australis released more nitrogen than S. alterniflora. Low salinity treatments in both lab and field experiments decayed more rapidly than high salinity treatments, suggesting that salinity inhibited microbial activity. Manipulation of inundation regime did not affect decomposition. These findings suggest the reintroduction of tidal flow to an impounded salt marsh can have mixed effects; recolonization by the native cordgrass could supply labile OM to sediment and slow carbon sequestration, while an increase in salinity might inhibit decomposition and accelerate sequestration.

  5. Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions.

    Directory of Open Access Journals (Sweden)

    John Y Takekawa

    Full Text Available Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus, and chick survival of Forster's Tern (Sterna forsteri. Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction

  6. Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions

    Science.gov (United States)

    Takekawa, John Y.; Ackerman, Joshua T.; Brand, Arriana; Graham, Tanya R.; Eagles-Smith, Collin A.; Herzog, Mark; Topping, Brent R.; Shellenbarger, Gregory; Kuwabara, James S.; Mruz, Eric; Piotter, Sara L.; Athearn, Nicole D.

    2015-01-01

    Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forster's Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality

  7. Effect of radiofrequency radiation from Wi-Fi devices on mercury release from amalgam restorations.

    Science.gov (United States)

    Paknahad, Maryam; Mortazavi, S M J; Shahidi, Shoaleh; Mortazavi, Ghazal; Haghani, Masoud

    2016-01-01

    Dental amalgam is composed of approximately 50% elemental mercury. Despite concerns over the toxicity of mercury, amalgam is still the most widely used restorative material. Wi-Fi is a rapidly using local area wireless computer networking technology. To the best of our knowledge, this is the first study that evaluates the effect of exposure to Wi-Fi signals on mercury release from amalgam restorations. Standard class V cavities were prepared on the buccal surfaces of 20 non-carious extracted human premolars. The teeth were randomly divided into 2 groups (n = 10). The control group was stored in non-environment. The specimens in the experimental groups were exposed to a radiofrequency radiation emitted from standard Wi Fi devices at 2.4 GHz for 20 min. The distance between the Wi-Fi router and samples was 30 cm and the router was exchanging data with a laptop computer that was placed 20 m away from the router. The concentration of mercury in the artificial saliva in the groups was evaluated by using a cold-vapor atomic absorption Mercury Analyzer System. The independent t test was used to evaluate any significant differences in mercury release between the two groups. The mean (±SD) concentration of mercury in the artificial saliva of the Wi-Fi exposed teeth samples was 0.056 ± .025 mg/L, while it was only 0.026 ± .008 mg/L in the non-exposed control samples. This difference was statistically significant (P =0.009). Exposure of patients with amalgam restorations to radiofrequency radiation emitted from conventional Wi-Fi devices can increase mercury release from amalgam restorations.

  8. Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions.

    Science.gov (United States)

    Takekawa, John Y; Ackerman, Joshua T; Brand, L Arriana; Graham, Tanya R; Eagles-Smith, Collin A; Herzog, Mark P; Topping, Brent R; Shellenbarger, Gregory G; Kuwabara, James S; Mruz, Eric; Piotter, Sara L; Athearn, Nicole D

    2015-01-01

    Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forster's Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forster's Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality

  9. Effects of hay management and native species sowing on grassland community structure, biomass, and restoration.

    Science.gov (United States)

    Foster, Bryan L; Kindscher, Kelly; Houseman, Greg R; Murphy, Cheryl A

    2009-10-01

    Prairie hay meadows are important reservoirs of grassland biodiversity in the tallgrass prairie regions of the central United States and are the object of increasing attention for conservation and restoration. In addition, there is growing interest in the potential use of such low-input, high-diversity (LIHD) native grasslands for biofuel production. The uplands of eastern Kansas, USA, which prior to European settlement were dominated by tallgrass prairie, are currently utilized for intensive agriculture or exist in a state of abandonment from agriculture. The dominant grasslands in the region are currently high-input, low-diversity (HILD) hay fields seeded to introduced C3 hay grasses. We present results from a long-term experiment conducted in a recently abandoned HILD hay field in eastern Kansas to evaluate effects of fertilization, haying, and native species sowing on community dynamics, biomass, and potential for restoration to native LIHD hay meadow. Fertilized plots maintained dominance by introduced grasses, maintained low diversity, and were largely resistant to colonization throughout the study. Non-fertilized plots exhibited rapid successional turnover, increased diversity, and increased abundance of C4 grasses over time. Haying led to modest changes in species composition and lessened the negative impact of fertilization on diversity. In non-fertilized plots, sowing increased representation by native species and increased diversity, successional turnover, and biomass production. Our results support the shifting limitations hypothesis of community organization and highlight the importance of species pools and seed limitations in constraining successional turnover, community structure, and ecosystem productivity under conditions of low fertility. Our findings also indicate that several biological and functional aspects of LIHD hay meadows can be restored from abandoned HILD hay fields by ceasing fertilization and reintroducing native species through

  10. The effect of different drinks on the color stability of different restorative materials after one month.

    Science.gov (United States)

    Tekçe, Neslihan; Tuncer, Safa; Demirci, Mustafa; Serim, Merve Efe; Baydemir, Canan

    2015-11-01

    The aim of this study was to evaluate the effect of three different drinks on the color parameters of four different restorative materials. Three different composites (Filtek Ultimate Universal Restorative, Filtek Ultimate Flowable, and Filtek Silorane, 3M ESPE) and a polyacid-modified composite resin material (Dyract XP, Dentsply DeTrey GmbH) were evaluated. Eighty-four disc-shaped specimens of 8 mm in diameter and 2 mm in thickness were prepared (n = 21 each). Color coordinates (L*a*b*, ΔL*, Δa*, Δb*, and ΔE*) were measured using a VİTA Easyshade Compact (VİTA Zahnfabrik) after 24 hr of storage (baseline) and after 30 day of storage in three different beverages of black tea, Coca cola, or water (control) (n = 7). In each beverage, the specimens were stored three times a day, one hr each, for 30 day. The color changes (ΔE) were calculated and were analyzed by Kruskal-Wallis and Dunn multiple comparison test. The color difference (ΔE*) of the resin materials ranged between 1.31 and 15.28 after 30 day of immersion in the staining solutions. Dyract XP in Coca cola (15.28 ± 2.61) and black tea (12.22 ± 2.73) showed the highest mean ΔE* value after 30 day, followed by Filtek Ultimate Universal Restorative (5.99 ± 1.25) and Filtek Ultimate Flowable (4.71 ± 1.40) in black tea (p < 0.05). The compomers displayed unacceptable color changes at the end of 30 day in all beverages. Among resin composites, the silorane based composite exhibited relatively good color stability than the others. Filtek Ultimate Universal Restorative and Filtek Flowable showed similar color changes in all beverages.

  11. In vitro comparative evaluation of the effect of two different fiber reinforcements on the fracture toughness of provisional restorative resins

    Directory of Open Access Journals (Sweden)

    Vaibhav D Kamble

    2012-01-01

    Clinical Implications: On the basis of this in--vitro study, the use of Glass and Polyethylene fibers tested may be an effective way to reinforce resins used to fabricate fixed provisional restorations.

  12. Effect of single interstitial impurity in iron-based superconductors with sign-changed s-wave pairing symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiang-Long, E-mail: xlyu@theory.issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Liu, Da-Yong; Quan, Ya-Min; Zheng, Xiao-Jun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Zou, Liang-Jian, E-mail: zou@theory.issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Department of Physics, University of Science and Technology of China, Hefei 230026 (China)

    2015-12-15

    Highlights: • Effects of single interstitial impurity are studied in iron-based superconductors. • Bound states within the superconducting gap can be induced. • The interstitial impurity can induce a π phase shift of pairing order parameter. • For strong magnetic scattering the bound-state peak can appear at the Fermi level. - Abstract: We employ the self-consistent Bogoliubov-de Gennes (BdG) formulation to investigate the effect of single interstitial nonmagnetic/magnetic impurity in iron-based superconductors with s ± -wave pairing symmetry. We find that both the nonmagnetic and magnetic impurities can induce bound states within the superconducting (SC) gap and a π phase shift of SC order parameter at the impurity site. However, different from the interstitial-nonmagnetic-impurity case characterized by two symmetric peaks with respect to zero energy, the interstitial magnetic one only induces single bound-state peak. In the strong scattering regime this peak can appear at the Fermi level, which has been observed in the recent scanning tunneling microscope (STM) experiment of Fe(Te,Se) superconductor with interstitial Fe impurities (Yin et al. 2015 [44]). This novel single in-gap peak feature also distinguishes the interstitial case from the substitutional one with two peaks. These results provide important information for comparing the different impurity effects in the iron-based superconductors.

  13. Few-layer and symmetry-breaking effects on the electrical properties of ordered CF3Cl phases on graphene

    Science.gov (United States)

    Morales-Cifuentes, Josue; Wang, Yilin; Reutt-Robey, Janice; Einstein, T. L.

    2014-03-01

    An effective pseudopotential mechanism for breaking the inherent sub-lattice symmetry of graphene has been studied using DFT calculations on hexagonal boron nitride. Electrical detection of CF3Cl phase transitions on graphene shows the existence of a commensurate ordered phase in which this can be tested. We study the electronic properties of this phase using VASP ver 5.3.3, with ab initio van der Waals density functionals (vdW-DF1 and vdW-DF2). Consistent with a physisorbed phase, binding energies and charge transfer per CF3Cl molecule are calculated to be on the order of 280meV and 0.01e, respectively. By exploring different coverages and orientations of this ordered phase we are able to open a band gap in some configurations; said gap is in the range of 8 to 80meV depending on the strength of the effective pseudopotential. Furthermore, we calculate the screening of these effects in bi-layer and tri-layer graphene. Work supported by NSF-MRSEC at UMD, grant DMR 05-20471 and NSF-CHE 13-05892.

  14. Origin of family symmetries

    International Nuclear Information System (INIS)

    Nilles, Hans Peter

    2012-04-01

    Discrete (family) symmetries might play an important role in models of elementary particle physics. We discuss the origin of such symmetries in the framework of consistent ultraviolet completions of the standard model in field and string theory. The symmetries can arise due to special geometrical properties of extra compact dimensions and the localization of fields in this geometrical landscape. We also comment on anomaly constraints for discrete symmetries.

  15. Origin of family symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Nilles, Hans Peter [Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Bonn Univ. (Germany). Physikalisches Inst.; Ratz, Michael [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Vaudrevange, Patrick K.S. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-04-15

    Discrete (family) symmetries might play an important role in models of elementary particle physics. We discuss the origin of such symmetries in the framework of consistent ultraviolet completions of the standard model in field and string theory. The symmetries can arise due to special geometrical properties of extra compact dimensions and the localization of fields in this geometrical landscape. We also comment on anomaly constraints for discrete symmetries.

  16. Electronic transport in single-helical protein molecules: Effects of multiple charge conduction pathways and helical symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Sourav, E-mail: sourav.kunduphy@gmail.com; Karmakar, S.N.

    2016-07-15

    We propose a tight-binding model to investigate electronic transport properties of single helical protein molecules incorporating both the helical symmetry and the possibility of multiple charge transfer pathways. Our study reveals that due to existence of both the multiple charge transfer pathways and helical symmetry, the transport properties are quite rigid under influence of environmental fluctuations which indicates that these biomolecules can serve as better alternatives in nanoelectronic devices than its other biological counterparts e.g., single-stranded DNA.

  17. Symmetry, asymmetry and dissymmetry

    International Nuclear Information System (INIS)

    Wackenheim, A.; Zollner, G.

    1987-01-01

    The authors discuss the concept of symmetry and defect of symmetry in radiological imaging and recall the definition of asymmetry (congenital or constitutional) and dissymmetry (acquired). They then describe a rule designed for the cognitive method of automatic evaluation of shape recognition data and propose the use of reversal symmetry [fr

  18. Weak C* Hopf Symmetry

    OpenAIRE

    Rehren, K. -H.

    1996-01-01

    Weak C* Hopf algebras can act as global symmetries in low-dimensional quantum field theories, when braid group statistics prevents group symmetries. Possibilities to construct field algebras with weak C* Hopf symmetry from a given theory of local observables are discussed.

  19. Gauge symmetry breaking

    International Nuclear Information System (INIS)

    Weinberg, S.

    1976-01-01

    The problem of how gauge symmetries of the weak interactions get broken is discussed. Some reasons why such a heirarchy of gauge symmetry breaking is needed, the reason gauge heirarchies do not seem to arise in theories of a given and related type, and the implications of theories with dynamical symmetry breaking, which can exhibit a gauge hierarchy

  20. Finite size effects and chiral symmetry breaking in quenched three-dimensional QED

    International Nuclear Information System (INIS)

    Hands, S.; Kogut, J.B.

    1990-01-01

    Finite size effects and the chiral condensate are studied in three-dimensional QED by the Lanczos and the conjugate-gradient algorithms. Very substantial finite size effects are observed, but studies on L 3 lattices with L ranging from 8 to 80 indicate the development of a non-vanishing chiral condensate in the continuum limit of the theory. The systematics of the finite size effects and the fermion mass dependence in the conjugate-gradient algorithm are clarified in this extensive study. (orig.)

  1. Negative differential resistance and rectification effects in zigzag graphene nanoribbon heterojunctions: Induced by edge oxidation and symmetry concept

    Science.gov (United States)

    Nazirfakhr, Maryam; Shahhoseini, Ali

    2018-03-01

    By applying non-equilibrium Green's functions (NEGF) in combination with tight-binding (TB) model, we investigate and compare the electronic transport properties of H-terminated zigzag graphene nanoribbon (H/ZGNR) and O-terminated ZGNR/H-terminated ZGNR (O/ZGNR-H/ZGNR) heterostructure under finite bias. Moreover, the effect of width and symmetry on the electronic transport properties of both models is also considered. The results reveal that asymmetric H/ZGNRs have linear I-V characteristics in whole bias range, but symmetric H-ZGNRs show negative differential resistance (NDR) behavior which is inversely proportional to the width of the H/ZGNR. It is also shown that the I-V characteristic of O/ZGNR-H/ZGNR heterostructure shows a rectification effect, whether the geometrical structure is symmetric or asymmetric. The fewer the number of zigzag chains, the bigger the rectification ratio. It should be mentioned that, the rectification ratios of symmetric heterostructures are much bigger than asymmetric one. Transmission spectrum, density of states (DOS), molecular projected self-consistent Hamiltonian (MPSH) and molecular eigenstates are analyzed subsequently to understand the electronic transport properties of these ZGNR devices. Our findings could be used in developing nanoscale rectifiers and NDR devices.

  2. Thermodynamics of lattice QCD with 2 quark flavours : chiral symmetry and topology

    International Nuclear Information System (INIS)

    Lagae, J.-F.

    1998-01-01

    We have studied the restoration of chiral symmetry in lattice QCD at the finite temperature transition from hadronic matter to a quark-gluon plasma. By measuring the screening masses of flavour singlet and non-singlet meson excitations, we have seen evidence that, although flavour chiral symmetry is restored at this transition, flavour singlet (U(1)) axial symmetry is not. We conclude that this indicates that instantons continue to play an important role in the quark-gluon plasma phase

  3. Gender symmetry in intimate aggression: an effect of intimacy or target sex?

    Science.gov (United States)

    Cross, Catharine P; Tee, William; Campbell, Anne

    2011-01-01

    Men's greater use of direct aggression is not evident in studies of intimate partner aggression. In previous research, the effects of target sex and relationship intimacy have frequently been confounded. This study sought to examine these effects separately. One hundred and seventy-four participants (59 male and 115 female) read vignette scenarios in which they were provoked by a same-sex best friend, an opposite-sex best friend, and a partner. For each target, participants estimated their likely use of direct physical and verbal aggression as well as noninjurious forms of anger expression. Results showed that men lower their aggression in the context of an intimate partnership and that this is an effect of the target's sex. In contrast, women raise their aggression in the context of an intimate partnership and this is an effect of intimacy with the target. The use of noninjurious angry behavior did not vary between targets for either sex of the participant, which suggests that the effects of target are confined to behaviors which carry an intention to harm. Possible effects of social norms and oxytocin-mediated emotional disinhibition on intimate partner aggression are discussed. © 2011 Wiley-Liss, Inc.

  4. Effects of Model Salivary Esterases and MMP Inhibition on the Restoration's Marginal Integrity and Potential Degradative Contribution of Cariogenic Bacteria

    Science.gov (United States)

    Huang, Bo

    Enzyme-catalyzed degradation of the restoration-tooth interface compromises interfacial integrity, thereby contributing to secondary caries, which is a major cause of resin-based restoration failure. It is hypothesized that in addition to salivary esterases, the cariogenic bacterium Streptococcus mutans has specific esterases that degrade the resin-dentin interface, releasing biodegradation by- products (BBPs) such as bis-hydroxy-propoxy-phenyl-propane (BisHPPP). In turn, BisHPPP affects S. mutans by stimulating the expression of esterases. Another hypothesis is that the biostability of the resin-dentin interface is affected by simulated salivary esterases, dentinal matrix metalloproteinase (MMP) inhibition, and restorative materials. To test the first hypothesis, putative esterase genes in S. mutans UA159 were identified, purified, and characterized. SMU_118c was identified as the dominant esterase in S. mutans UA159 and showed a similar hydrolytic activity profile to salivary esterases. BisHPPP upregulated expression of the SMU_118c gene and related protein in a concentration-dependent manner. This positive feedback process could accelerate the degradation of the restoration-tooth interface and lead to premature restoration failure. To test the second hypothesis, an in vitro model was established to evaluate the effects of salivary esterases, MMP inhibition and restorative materials on interfacial integrity. It was confirmed that interfacial integrity was compromised with time and was further deteriorated by simulated salivary esterases, as indicated by the greater depth of bacterial ingress and more bacterial biomass of biofilm along the interface. However, this process could be modulated by using different restorative materials and MMPs inhibition. This project elucidated the mechanistic interaction between oral bacteria and restorative materials and established a new, in vitro, and physiologically relevant model to assess the effect of material chemistry

  5. A density functional reactivity theory (DFRT) based approach to understand the effect of symmetry of fullerenes on the kinetic, thermodynamic and structural aspects of carbon NanoBuds

    Energy Technology Data Exchange (ETDEWEB)

    Sarmah, Amrit; Roy, Ram Kinkar, E-mail: rkroy2@rediffmail.com

    2016-06-15

    Highlights: • Kinetic and thermodynamic aspects of the interaction between fullerene (C{sub 32}) and SWCNT using CDASE scheme. • Role of symmetry of fullerenes as well as the site of covalent attachment to the SWCNT in the structural stability of the NanoBud structure. • Increase in the fullerene symmetry improves the relative stability of hybrid NanoBud structure. - Abstract: In the present study, we have rationalized the effect of variation in the symmetry of relatively smaller fullerene (C{sub 32}) on the mode of its interaction with semi-conducting Single-Walled Carbon Nanotubes (SWCNTs) in the process of formation of stable hybrid carbon NanoBuds. Thermodynamic and kinetic parameters, along with the charge transfer values associated with the interaction between fullerene and SWCNTs, have been evaluated using an un-conventional and computationally cost–effective method based on density functional reactivity theory (DFRT). In addition to this, conventional DFT based studies are also performed to substantiate the growth of NanoBud structures formed by the interaction between fullerene and SWCNTs. The findings of the present study suggest that the kinetic, thermodynamic and structural aspects of hybrid carbon NanoBuds are significantly influenced by both the symmetry of C{sub 32} fullerene and its site of covalent attachment to the SWCNT.

  6. Inversion symmetry and bulk Rashba effect in methylammonium lead iodide perovskite single crystals

    KAUST Repository

    Frohna, Kyle

    2018-05-02

    Methylammonium lead iodide perovskite (MAPbI3) exhibits long charge carrier lifetimes that are linked to its high efficiency in solar cells. Yet, the mechanisms governing these unusual carrier dynamics are not completely understood. A leading hypothesis-disproved in this work-is that a large, static bulk Rashba effect slows down carrier recombination. Here, using second harmonic generation rotational anisotropy measurements on MAPbI3 crystals, we demonstrate that the bulk structure of tetragonal MAPbI3 is centrosymmetric with I4/mcm space group. Our calculations show that a significant Rashba splitting in the bandstructure requires a non-centrosymmetric lead iodide framework, and that incorrect structural relaxations are responsible for the previously predicted large Rashba effect. The small Rashba splitting allows us to compute effective masses in excellent agreement with experiment. Our findings rule out the presence of a large static Rashba effect in bulk MAPbI3, and our measurements find no evidence of dynamic Rashba effects.

  7. Inversion symmetry and bulk Rashba effect in methylammonium lead iodide perovskite single crystals

    KAUST Repository

    Frohna, Kyle; Deshpande, Tejas; Harter, John; Peng, Wei; Barker, Bradford A.; Neaton, Jeffrey B.; Louie, Steven G.; Bakr, Osman; Hsieh, David; Bernardi, Marco

    2018-01-01

    Methylammonium lead iodide perovskite (MAPbI3) exhibits long charge carrier lifetimes that are linked to its high efficiency in solar cells. Yet, the mechanisms governing these unusual carrier dynamics are not completely understood. A leading hypothesis-disproved in this work-is that a large, static bulk Rashba effect slows down carrier recombination. Here, using second harmonic generation rotational anisotropy measurements on MAPbI3 crystals, we demonstrate that the bulk structure of tetragonal MAPbI3 is centrosymmetric with I4/mcm space group. Our calculations show that a significant Rashba splitting in the bandstructure requires a non-centrosymmetric lead iodide framework, and that incorrect structural relaxations are responsible for the previously predicted large Rashba effect. The small Rashba splitting allows us to compute effective masses in excellent agreement with experiment. Our findings rule out the presence of a large static Rashba effect in bulk MAPbI3, and our measurements find no evidence of dynamic Rashba effects.

  8. Dynamical effects of exchange symmetry breaking in mixtures of interacting bosons

    DEFF Research Database (Denmark)

    Tichy, Malte C.; Sherson, Jacob; Mølmer, Klaus

    2012-01-01

    of two distinguishable species with identical physical properties, that is, which are governed by an isospecific interaction and external potential. In the mean-field limit, the spatial population imbalance of the mixture can be described by the dynamics of a single species in an effective potential...... approximates the full counting statistics well also outside the realm of spin-coherent states. The method is extended to general Bose-Hubbard systems and to their classical mean-field limits, which suggests an effective single-species description of multicomponent Bose gases with weakly an...... with modified properties or, equivalently, with an effective total particle number. The oscillation behavior can be tuned by populating the second species while maintaining the spatial population imbalance and all other parameters constant. In the corresponding many-body approach, the single-species description...

  9. Advancements in all-ceramics for dental restorations and their effect on the wear of opposing dentition

    Science.gov (United States)

    Rashid, Haroon; Sheikh, Zeeshan; Misbahuddin, Syed; Kazmi, Murtaza Raza; Qureshi, Sameer; Uddin, Muhammad Zuhaib

    2016-01-01

    Tooth wear is a process that is usually a result of tooth to tooth and/or tooth and restoration contact. The process of wear essentially becomes accelerated by the introduction of restorations inside the oral cavity, especially in case of opposing ceramic restorations. The newest materials have vastly contributed toward the interest in esthetic dental restorations and have been extensively studied in laboratories. However, despite the recent technological advancements, there has not been a valid in vivo method of evaluation involving clinical wear caused due to ceramics upon restored teeth and natural dentition. The aim of this paper is to review the latest advancements in all-ceramic materials, and their effect on the wear of opposing dentition. The descriptive review has been written after a thorough MEDLINE/PubMed search by the authors. It is imperative that clinicians are aware of recent advancements and that they should always consider the type of ceramic restorative materials used to maintain a stable occlusal relation. The ceramic restorations should be adequately finished and polished after the chair-side adjustment process of occlusal surfaces. PMID:28042280

  10. Effect of Dental Restorative Material Type and Shade on Characteristics of Two-Layer Dental Composite Systems

    Directory of Open Access Journals (Sweden)

    Atefeh Karimzadeh

    Full Text Available Abstract The purpose of this study was to investigate the effects of shade and material type and shape in dental polymer composites on the hardness and shrinkage stress of bulk and two-layered restoration systems. For this purpose, some bulk and layered specimens from three different shades of dental materials were prepared and light-cured. The experiments were carried out on three types of materials: conventional restorative composite, nanohybrid composite and nanocomposite. Micro-indentation experiment was performed on the bulk and also on each layer of layered restoration specimens using a Vicker's indenter. The interface between the two layers was studied by scanning electron microscopy (SEM. The results revealed significant differences between the values of hardness for different shades in the conventional composite and also in the nanohybrid composite. However, no statistically significant difference was observed between the hardness values for different shades in the nanocomposite samples. The layered restoration specimens of different restorative materials exhibited lower hardness values with respect to their bulk specimens. The reduction in the hardness value of the layered conventional composite samples was higher than those of the nanocomposite and nanohybrid composite specimens indicating more shrinkage stresses generated in the conventional composite restorations. According to the SEM images, a gap was observed between the two layers in the layered restorations.

  11. Effects of ecosystem development on benthic secondary production in restored and created mangrove habitats

    Science.gov (United States)

    Wetland creation, enhancement, and restoration activities are commonly implemented to compensate for wetland loss or degradation. However, functional equivalence in restored and created wetland habitats is often poorly understood. In estuarine habitats, changes in habitat qualit...

  12. The Effect of Height, Wing Length, and Wing Symmetry on Tabebuia rosea Seed Dispersal

    Directory of Open Access Journals (Sweden)

    Yasmeen Moussa

    2014-12-01

    Full Text Available The relationship between the vertical drop height and the horizontal distance traveled (dispersal ratio was investigated for a sample of fifty Tabebuia rosea seeds by dropping the seeds from five heights ranging from 1.00 to 2.00 meters. The dispersal ratio was found to be a constant 0.16 m/m for these heights. The effects of total seed length and asymmetry of seed wings on dispersal ratio were also measured using separate samples of fifty Tabebuia rosea seeds. It was found that neither seed length nor asymmetry had a significant effect on the dispersal ratio.

  13. Symmetry in running.

    Science.gov (United States)

    Raibert, M H

    1986-03-14

    Symmetry plays a key role in simplifying the control of legged robots and in giving them the ability to run and balance. The symmetries studied describe motion of the body and legs in terms of even and odd functions of time. A legged system running with these symmetries travels with a fixed forward speed and a stable upright posture. The symmetries used for controlling legged robots may help in elucidating the legged behavior of animals. Measurements of running in the cat and human show that the feet and body sometimes move as predicted by the even and odd symmetry functions.

  14. Symmetries of Chimera States

    Science.gov (United States)

    Kemeth, Felix P.; Haugland, Sindre W.; Krischer, Katharina

    2018-05-01

    Symmetry broken states arise naturally in oscillatory networks. In this Letter, we investigate chaotic attractors in an ensemble of four mean-coupled Stuart-Landau oscillators with two oscillators being synchronized. We report that these states with partially broken symmetry, so-called chimera states, have different setwise symmetries in the incoherent oscillators, and in particular, some are and some are not invariant under a permutation symmetry on average. This allows for a classification of different chimera states in small networks. We conclude our report with a discussion of related states in spatially extended systems, which seem to inherit the symmetry properties of their counterparts in small networks.

  15. Parastatistics and gauge symmetries

    International Nuclear Information System (INIS)

    Govorkov, A.B.

    1982-01-01

    A possible formulation of gauge symmetries in the Green parafield theory is analysed and the SO(3) gauge symmetry is shown to be on a distinct status. The Greenberg paraquark hypothesis turns out to be not equivalent to the hypothesis of quark colour SU(3)sub(c) symmetry. Specific features of the gauge SO(3) symmetry are discussed, and a possible scheme where it is an exact subgroup of the broken SU(3)sub(c) symmetry is proposed. The direct formulation of the gauge principle for the parafield represented by quaternions is also discussed

  16. Gauge symmetry, chirality and parity effects in four-particle systems: Coulomb's law as a universal function for diatomic molecules.

    Science.gov (United States)

    Van Hooydonk, G

    2000-11-01

    Following recent work in search for a universal function (Van Hooydonk, Eur. J. Inorg. Chem., (1999), 1617), we test four symmetric +/- a(n)Rn potentials for reproducing molecular potential energy curves (PECs). Classical gauge symmetry for 1/R-potentials results in generic left right asymmetric PECs. A pair of symmetric perturbed Coulomb potentials is quantitatively in accordance with observed PECs. For a bond, a four-particle system, charge inversion (a parity effect, atom chirality) is the key to explain this shape generically. A parity adapted Hamiltonian reduces from ten to two terms and to a soluble Bohr-like formula, a Kratzer (1 - Re/R)2 potential. The result is similar to the combined action of spin and wave function symmetry upon the Hamiltonian in Heitler-London theory. Analytical perturbed Coulomb functions varying with (1 - Re/R) scale attractive and repulsive branches of PECs for 13 bonds H2, HF, LiH, KH, AuH, Li2, LiF, KLi, NaCs, Rb2, RbCs, Cs2 and I2 in a single straight line. The 400 turning points for 13 bonds are reproduced with a deviation of 0.007 A at both branches. For 230 points at the repulsive side, the deviation is 0.003 A. The perturbed electrostatic Coulomb law is a universal molecular function. Ab initio zero molecular parameter functions give PECs of acceptable quality, just using atomic ionisation energies. The function can be used as a model potential for inverting levels and gives a first principle's comparison of short- and long-range interactions, important for the study of cold atoms. Wave-packet dynamics, femto-chemistry applied to the crossing of covalent and ionic curves, can provide evidence for this theory. We anticipate this scale/shape invariant scheme applies to smaller scales in nuclear and high-energy particle physics. For larger gravitational scales (Newton 1/R potentials), problems with super-unification are discussed. Reactions between hydrogen and antihydrogen, feasible in the near future, will probably produce

  17. Generalized global symmetries

    International Nuclear Information System (INIS)

    Gaiotto, Davide; Kapustin, Anton; Seiberg, Nathan; Willett, Brian

    2015-01-01

    A q-form global symmetry is a global symmetry for which the charged operators are of space-time dimension q; e.g. Wilson lines, surface defects, etc., and the charged excitations have q spatial dimensions; e.g. strings, membranes, etc. Many of the properties of ordinary global symmetries (q=0) apply here. They lead to Ward identities and hence to selection rules on amplitudes. Such global symmetries can be coupled to classical background fields and they can be gauged by summing over these classical fields. These generalized global symmetries can be spontaneously broken (either completely or to a subgroup). They can also have ’t Hooft anomalies, which prevent us from gauging them, but lead to ’t Hooft anomaly matching conditions. Such anomalies can also lead to anomaly inflow on various defects and exotic Symmetry Protected Topological phases. Our analysis of these symmetries gives a new unified perspective of many known phenomena and uncovers new results.

  18. Mirror symmetry and Coulomb effects in light N ≅ Z nuclei

    International Nuclear Information System (INIS)

    Bentley, M.A.; Williams, S.J.; Joss, D.T.

    2002-01-01

    Some latest results from gamma-ray spectroscopic studies of high spin states of isobaric multiplets are presented. An experimental programme is underway to examine exited states of isobaric multiplets of total isospin T 1/2 and T = 1 and the comparison of energies of excited states can be interpreted in terms of Coulomb effects. Through a systematic study of these Coulomb effects, and through examination of the calculated Coulomb energies from full pf-shell model calculations, it is now becoming clear that measurement of Coulomb energies can yield very detailed information on the evolution of nuclear structure phenomena as a function of energy and angular momentum. In this contribution, latest results of studies of isobaric analogue states at high spin in the A = 50, 51 and 53 systems are presented. (author)

  19. Adaptive Management and Monitoring as Fundamental Tools to Effective Salt Marsh Restoration

    Science.gov (United States)

    Adaptive management as applied to ecological restoration is a systematic decision-making process in which the results of restoration activities are repeatedly monitored and evaluated to provide guidance that can be used in determining any necessary future restoration actions. In...

  20. Effects of aquatic physiotherapy on the improvement of balance and corporal symmetry in stroke survivors

    OpenAIRE

    Montagna, Jéssica Cristine; Santos, Bárbara C; Battistuzzo, Camila R; Loureiro, Ana Paula C

    2014-01-01

    Introduction: One of the main problems associate with hemiparesis after stroke is the decrease in balance during static and dynamic postures which can highly affect daily life activities. Objective: To assess the effects of aquatic physiotherapy on the balance and quality of life (SS-QoL) of people with pos stroke. Methods: Chronic stroke participants received at total 18 individual sessions of aquatic physiotherapy using the principle of Halliwick (2x of 40 minutes per week). The outcomes me...

  1. Symmetry-Dependent Spin Transport Properties and Spin-Filter Effects in Zigzag-Edged Germanene Nanoribbons

    Directory of Open Access Journals (Sweden)

    Can Cao

    2015-01-01

    Full Text Available We performed the first-principles calculations to investigate the spin-dependent electronic transport properties of zigzag-edged germanium nanoribbons (ZGeNRs. We choose of ZGeNRs with odd and even widths of 5 and 6, and the symmetry-dependent transport properties have been found, although the σ mirror plane is absent in ZGeNRs. Furthermore, even-N and odd-N ZGeNRs have very different current-voltage relationships. We find that the even 6-ZGeNR shows a dual spin-filter effect in antiparallel (AP magnetism configuration, but the odd 5-ZGeNR behaves as conventional conductors with linear current-voltage dependence. It is found that when the two electrodes are in parallel configuration, the 6-ZGeNR system is in a low resistance state, while it can switch to a much higher resistance state when the electrodes are in AP configuration, and the magnetoresistance of 270% can be observed.

  2. Chiral and parity symmetry breaking for planar fermions: Effects of a heat bath and uniform external magnetic field

    International Nuclear Information System (INIS)

    Ayala, Alejandro; Bashir, Adnan; Gutierrez, Enif; Raya, Alfredo; Sanchez, Angel

    2010-01-01

    We study chiral symmetry breaking for relativistic fermions, described by a parity-violating Lagrangian in 2+1-dimensions, in the presence of a heat bath and a uniform external magnetic field. Working within their four-component formalism allows for the inclusion of both parity-even and -odd mass terms. Therefore, we can define two types of fermion antifermion condensates. For a given value of the magnetic field, there exist two different critical temperatures which would render one of these condensates identically zero, while the other would survive. Our analysis is completely general: it requires no particular simplifying hierarchy among the energy scales involved, namely, bare masses, field strength, and temperature. However, we do reproduce some earlier results, obtained or anticipated in literature, corresponding to special kinematical regimes for the parity conserving case. Relating the chiral condensate to the one-loop effective Lagrangian, we also obtain the magnetization and the pair production rate for different fermion species in a uniform electric field through the replacement B→-iE.

  3. The effect of a nanofilled resin-based coating on water absorption by teeth restored with glass ionomer.

    Science.gov (United States)

    Hankins, Amanda D; Hatch, Robert H; Benson, Jarred H; Blen, Bernard J; Tantbirojn, Daranee; Versluis, Antheunis

    2014-04-01

    A nanofilled, resin-based light-cured coating (G-Coat Plus, GC America, Alsip, Ill.) may reduce water absorption by glass ionomers. The authors investigated this possibility by measuring cuspal flexure caused by swelling of glass ionomer-restored teeth. The authors cut large mesio-occlusodistal slots (4-millimeter wide, 4-mm deep) in 12 extracted premolars and restored them with a glass ionomer cement (Fuji IX GP Extra, GC America). Six teeth were coated, and the other six were uncoated controls. The authors digitized the teeth in three dimensions by using an optical scanner after preparation and restoration and during an eight-week storage in water. They calculated cuspal flexure and analyzed the results by using an analysis of variance and Student-Newman-Keuls post hoc tests (significance level .05). They used dye penetration along the interface to verify bonding. Inward cuspal flexure indicated restoration shrinkage. Coated restorations had significantly higher flexure (mean [standard deviation], -11.9 [3.5] micrometers) than did restorations without coating (-7.3 [1.5] μm). Flexure in both groups decreased significantly (P < .05) during water storage and, after eight weeks, it changed to expansion for uncoated control restorations. Dye penetration along the interfaces was not significant, which ruled out debonding as the cause of cuspal relaxation. Teeth restored with glass ionomer cement exhibited shrinkage, as seen by inward cuspal flexure. The effect of the protective coating on water absorption was evident in the slower shrinkage compensation. The study results show that teeth restored with glass ionomers exhibited setting shrinkage that deformed tooth cusps. Water absorption compensated for the shrinkage. Although the coating may be beneficial for reducing water absorption, it also slows the shrinkage compensation rate (that is, the rate that hygroscopic expansion compensates for cuspal flexure from shrinkage).

  4. Broken SU(4) symmetry and new resonance

    International Nuclear Information System (INIS)

    Ueda, Y.

    1975-11-01

    Weinberg's spectral function sum rules are modified to accommodate broken symmetry effects of SU(4). With a simple choice of the symmetry-breaking term, the spectral function sum rules yield the observed vector meson mass spectrum as well as sum rules for the e - e + decay rates of vector mesons. In particular, a new mass formula, which can be interpreted as the broken symmetry version of the Schwinger formula, is derived, the agreement with experiments is excellent. (Ueda, Y.)

  5. Symmetry and symmetry breaking in quantum mechanics

    International Nuclear Information System (INIS)

    Chomaz, Philippe

    1998-01-01

    In the world of infinitely small, the world of atoms, nuclei and particles, the quantum mechanics enforces its laws. The discovery of Quanta, this unbelievable castration of the Possible in grains of matter and radiation, in discrete energy levels compels us of thinking the Single to comprehend the Universal. Quantum Numbers, magic Numbers and Numbers sign the wave. The matter is vibration. To describe the music of the world one needs keys, measures, notes, rules and partition: one needs quantum mechanics. The particles reduce themselves not in material points as the scholars of the past centuries thought, but they must be conceived throughout the space, in the accomplishment of shapes of volumes. When Einstein asked himself whether God plays dice, there was no doubt among its contemporaries that if He exists He is a geometer. In a Nature reduced to Geometry, the symmetries assume their role in servicing the Harmony. The symmetries allow ordering the energy levels to make them understandable. They impose there geometrical rules to the matter waves, giving them properties which sometimes astonish us. Hidden symmetries, internal symmetries and newly conceived symmetries have to be adopted subsequently to the observation of some order in this world of Quanta. In turn, the symmetries provide new observables which open new spaces of observation

  6. Monitoring the effect of restoration measures in Indonesian peatlands by radar satellite imagery.

    Science.gov (United States)

    Jaenicke, J; Englhart, S; Siegert, F

    2011-03-01

    In the context of the ongoing climate change discussions the importance of peatlands as carbon stores is increasingly recognised in the public. Drainage, deforestation and peat fires are the main reasons for the release of huge amounts of carbon from peatlands. Successful restoration of degraded tropical peatlands is of high interest due to their huge carbon store and sequestration potential. The blocking of drainage canals by dam building has become one of the most important measures to restore the hydrology and the ecological function of the peat domes. This study investigates the capability of using multitemporal radar remote sensing imagery for monitoring the hydrological effects of these measures. The study area is the former Mega Rice Project area in Central Kalimantan, Indonesia, where peat drainage and forest degradation is especially intense. Restoration measures started in July 2004 by building 30 large dams until June 2008. We applied change detection analysis with more than 80 ENVISAT ASAR and ALOS PALSAR images, acquired between 2004 and 2009. Radar signal increases of up to 1.36 dB show that high frequency multitemporal radar satellite imagery can be used to detect an increase in peat soil moisture after dam construction, especially in deforested areas with a high density of dams. Furthermore, a strong correlation between cross-polarised radar backscatter coefficients and groundwater levels above -50 cm was found. Monitoring peatland rewetting and quantifying groundwater level variations is important information for vegetation re-establishment, fire hazard warning and making carbon emission mitigation tradable under the voluntary carbon market or REDD (Reducing Emissions from Deforestation and Degradation) mechanism. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Effects of aquatic physiotherapy on the improvement of balance and corporal symmetry in stroke survivors.

    Science.gov (United States)

    Montagna, Jéssica Cristine; Santos, Bárbara C; Battistuzzo, Camila R; Loureiro, Ana Paula C

    2014-01-01

    One of the main problems associate with hemiparesis after stroke is the decrease in balance during static and dynamic postures which can highly affect daily life activities. To assess the effects of aquatic physiotherapy on the balance and quality of life (SS-QoL) of people with pos stroke. Chronic stroke participants received at total 18 individual sessions of aquatic physiotherapy using the principle of Halliwick (2x of 40 minutes per week). The outcomes measured were: Berg Balance scale, Timed up & go test (TUG), Stroke Specific Quality of Life Scale (SS-QoL) and baropodometric analysis. These assessment were performed before and one week after intervention. Fifteen participants were included in this study. The mean age was 58.5 and 54% was male. After intervention, participants had a significant improvement on their static balance measured by Berg Balance scale and TUG. Dynamic balance had a significant trend of improvement in mediolateral domain with eyes closed and during sit-to-stand. The mobility domain of the SS-QoL questionnaire was significant higher after intervention. Our results suggest that aquatic physiotherapy using the method of Halliwick can be a useful tool during stroke rehabilitation to improve balance. However, this improvement may not have significant impact of their quality of life.

  8. Symmetries in nature

    International Nuclear Information System (INIS)

    Mainzer, K.

    1988-01-01

    Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs

  9. Symmetries in nature

    Energy Technology Data Exchange (ETDEWEB)

    Mainzer, K

    1988-05-01

    Symmetry, disymmetry, chirality etc. are well-known topics in chemistry. But they cannot only be found on the molecular level of matter. Atoms and elementary particles in physics are also characterized by particular symmetry groups. Even living organisms and populations on the macroscopic level have functional properties of symmetry. The whole physical, chemical, and biological evolution seems to be regulated by the emergence of new symmetries and the breaking down of old ones. One is reminded of Heisenberg's famous statement: 'Die letzte Wurzel der Erscheinungen ist also nicht die Materie, sondern das mathematische Gesetz, die Symmetrie, die mathematische Form' (Wandlungen in den Grundlagen der Naturwissenschaften, 1959). Historically the belief in symmetry and simplicity of nature has a long philosophical tradition from the Pythagoreans, Plato and Greek astronomers to Kepler and modern scientists. Today, 'symmetries in nature' is a common topic of mathematics, physics, chemistry, and biology. A lot of Nobel prizes were given in honour of inquiries concerning symmetries in nature. The fascination of symmetries is not only motivated by science, but by art and religion too. Therefore 'symmetris in nature' is an interdisciplinary topic which may help to overcome C.P. Snow's 'Two Cultures' of natural sciences and humanities. (author) 17 refs., 21 figs.

  10. Symmetries in nuclei

    International Nuclear Information System (INIS)

    Arima, A.

    2003-01-01

    (1) There are symmetries in nature, and the concept of symmetry has been used in art and architecture. The symmetry is evaluated high in the European culture. In China, the symmetry is broken in the paintings but it is valued in the architecture. In Japan, however, the symmetry has been broken everywhere. The serious and interesting question is why these differences happens? (2) In this lecture, I reviewed from the very beginning the importance of the rotational symmetry in quantum mechanics. I am sorry to be too fundamental for specialists of nuclear physics. But for people who do not use these theories, I think that you could understand the mathematical aspects of quantum mechanics and the relation between the angular momentum and the rotational symmetry. (3) To the specialists of nuclear physics, I talked about my idea as follows: dynamical treatment of collective motions in nuclei by IBM, especially the meaning of the degeneracy observed in the rotation bands top of γ vibration and β vibration, and the origin of pseudo-spin symmetry. Namely, if there is a symmetry, a degeneracy occurs. Conversely, if there is a degeneracy, there must be a symmetry. I discussed some details of the observed evidence and this correspondence is my strong belief in physics. (author)

  11. Big break for charge symmetry

    CERN Document Server

    Miller, G A

    2003-01-01

    Two new experiments have detected charge-symmetry breaking, the mechanism responsible for protons and neutrons having different masses. Symmetry is a crucial concept in the theories that describe the subatomic world because it has an intimate connection with the laws of conservation. The theory of the strong interaction between quarks - quantum chromodynamics - is approximately invariant under what is called charge symmetry. In other words, if we swap an up quark for a down quark, then the strong interaction will look almost the same. This symmetry is related to the concept of sup i sospin sup , and is not the same as charge conjugation (in which a particle is replaced by its antiparticle). Charge symmetry is broken by the competition between two different effects. The first is the small difference in mass between up and down quarks, which is about 200 times less than the mass of the proton. The second is their different electric charges. The up quark has a charge of +2/3 in units of the proton charge, while ...

  12. Coulomb effects in three-nucleon scattering versus charge-symmetry breaking in the 3P nucleon-nucleon interactions

    International Nuclear Information System (INIS)

    Tornow, W.; Howell, C.R.; Walter, R.L.; Slaus, I.

    1992-01-01

    Comparison of data for neutron-deuteron and proton-deuteron analyzing power A y for elastic scattering has become crucial for investigating charge-symmetry breaking in the 3 P nucleon-nucleon interactions. We extended this comparison down to 5 MeV and find that the relative difference between n-d and p-d scattering at the A y maximum near 120 degree increases with decreasing energy. By applying a straightforward Coulomb ''correction'' to the p-d data, we account for most of the difference, suggesting that the Coulomb force, rather than charge-symmetry breaking, is responsible for most of the observed difference

  13. Effect of the cavity configuration factor on the marginal microleakage of esthetic restorative materials.

    Science.gov (United States)

    Franco, Eduardo Batista; Gonzaga Lopes, Lawrence; Lia Mondelli, Rafael Francisco; da Silva e Souza, Mário Honorato; Pereira Lauris, José Roberto

    2003-06-01

    To evaluate the effect of the cavity configuration factor (CF) on the marginal microleakage of cervical restorations with four aesthetic restorative materials. Conventional cavities, 2.9 mm in diameter and 1.5 mm deep, with CF=2.7 and "saucer"-shaped ones with CF=2 were created in 60 extracted premolars. The following groups were established: G1: Z100/Single Bond, G2: Freedom/Stae, G3: Vitremer/Primer and G4: Durafill/Durafill Bond, following each manufacturer's directions. Thermocycling of the specimens was performed in an aqueous solution of 2% buffered methylene blue, with the temperature varying between 5 to 55 degrees C, for a total of cycles of 60 minutes per day, for 7 days. The specimens were then sectioned and evaluated by two observers using photographs acquired from a stereomicroscope. The values were subjected to Kruskal-Wallis analysis and the Dunn and Wilcoxon test. The averages of the microleakage scores observed in the conventional and "saucer"-shaped cavities were respectively: G1: 0.66/0.46; G2: 0.92/0.69; G3: 1.8/1.86; G4: 3.54/2.3.

  14. Effect of a Simulation Exercise on Restorative Identification Skills of First Year Dental Hygiene Students.

    Science.gov (United States)

    Lemaster, Margaret; Flores, Joyce M; Blacketer, Margaret S

    2016-02-01

    This study explored the effectiveness of simulated mouth models to improve identification and recording of dental restorations when compared to using traditional didactic instruction combined with 2-dimensional images. Simulation has been adopted into medical and dental education curriculum to improve both student learning and patient safety outcomes. A 2-sample, independent t-test analysis of data was conducted to compare graded dental recordings of dental hygiene students using simulated mouth models and dental hygiene students using 2-dimensional photographs. Evaluations from graded dental charts were analyzed and compared between groups of students using the simulated mouth models containing random placement of custom preventive and restorative materials and traditional 2-dimensional representations of didactically described conditions. Results demonstrated a statistically significant (p≤0.0001) difference: for experimental group, students using the simulated mouth models to identify and record dental conditions had a mean of 86.73 and variance of 33.84. The control group students using traditional 2-dimensional images mean graded dental chart scores were 74.43 and variance was 14.25. Using modified simulation technology for dental charting identification may increase level of dental charting skill competency in first year dental hygiene students. Copyright © 2016 The American Dental Hygienists’ Association.

  15. Effects of landscape gradients on wetland vegetation communities: information for large-scale restoration

    Science.gov (United States)

    Zweig, Christa L.; Kitchens, Wiley M.

    2008-01-01

    Projects of the scope of the restoration of the Florida Everglades require substantial information regarding ecological mechanisms, and these are often poorly understood. We provide critical base knowledge for Everglades restoration by characterizing the existing vegetation communities of an Everglades remnant, describing how present and historic hydrology affect wetland vegetation community composition, and documenting change from communities described in previous studies. Vegetation biomass samples were collected along transects across Water Conservation Area 3A South (3AS). Ten community types were present between November 2002 and 2005. Separate analyses for key a priori groups (slough, wet prairie, and sawgrass) provided detailed conclusions about effects of historic hydrology on the vegetation of 3AS. Communities were affected by hydrologic variables LIP to four years previous to the sample. We identified wet prairie/slough species such as Eleocharis spp. and Nymphaea odorata as short-term sentinel species of community change. Sawgrass and N. odorata should be monitored for long-term change. Comparisons to preceding studies indicated that many of the communities of previous times, when conditions were drier, no longer exist in our study area and have been replaced by deeper water community types.

  16. Examining the effectiveness of a restorative justice program for various types of juvenile offenders.

    Science.gov (United States)

    Bergseth, Kathleen J; Bouffard, Jeffrey A

    2013-09-01

    Restorative justice (RJ) programs have become widespread in the United States and in other countries. These programs are often seen as a viable alternative to traditional retributive processing, especially for minor, and sometimes more serious, forms of delinquency and adult criminality. The programs hold promise for achieving several goals, including increased community and victim involvement, greater satisfaction with the case outcomes, improved offender compliance, increased perceptions of fairness, and even recidivism reduction. Meta-analyses have demonstrated varying degrees of program success in recidivism reduction, which may in part reflect differential effectiveness of the RJ approach for various kinds of offenders. This study examined whether an RJ program for juvenile offenders had differential impacts on recidivism across various offender characteristics (including age, gender, racial group, offending history, and current offense). Results generally support the effectiveness of the program for many types of offenders. Implications for future research and potential improvements to the RJ model are discussed.

  17. Restoration of floodplain meadows: Effects on the re-establishment of mosses

    Science.gov (United States)

    Wolski, Grzegorz J.; Harnisch, Matthias; Otte, Annette; Bomanowska, Anna; Donath, Tobias W.

    2017-01-01

    Vascular plants serve as target species for the evaluation of restoration success as they account for most of the plant species diversity and vegetation cover. Although bryophytes contribute considerably to the species diversity of meadows, they are rarely addressed in restoration projects. This project is a first step toward making recommendations for including mosses in alluvial floodplain restoration projects. The opportunity to assess the diversity and ecological requirements of mosses on floodplain meadows presented itself within the framework of a vegetation monitoring that took place in 2014 on meadows located along the northern Upper Rhine. In this area, large-scale meadow restoration projects have taken place since 1997 in both the functional and fossil floodplains. Other studies have shown that bryophytes are generally present in green hay used in restoration, providing inadvertent bryophyte introduction. We compared bryophyte communities in donor and restored communities and correlated these communities with environmental variables—taking into account that the mosses on the restoration sites possibly developed from green hay. This analysis provided insights as to which species of bryophytes should be included in future restoration projects, what diaspores should be used, and how they should be transferred. Data on bryophyte occurrence were gathered from old meadows, and from restoration sites. We found distinct differences in bryophyte composition (based on frequency) in restored communities in functional flood plains compared to donor communities. Generally, restoration sites are still characterized by a lower species-richness, with a significantly lower occurrence of rare and red listed species and a lower species-heterogeneity. In conclusion, our research establishes what mosses predominate in donor and restored alluvial meadows along the northern Upper River, and what microsite conditions favour particular species. This points the way to deliberate

  18. Translational Symmetry and Microscopic Constraints on Symmetry-Enriched Topological Phases: A View from the Surface

    Directory of Open Access Journals (Sweden)

    Meng Cheng

    2016-12-01

    Full Text Available The Lieb-Schultz-Mattis theorem and its higher-dimensional generalizations by Oshikawa and Hastings require that translationally invariant 2D spin systems with a half-integer spin per unit cell must either have a continuum of low energy excitations, spontaneously break some symmetries, or exhibit topological order with anyonic excitations. We establish a connection between these constraints and a remarkably similar set of constraints at the surface of a 3D interacting topological insulator. This, combined with recent work on symmetry-enriched topological phases with on-site unitary symmetries, enables us to develop a framework for understanding the structure of symmetry-enriched topological phases with both translational and on-site unitary symmetries, including the effective theory of symmetry defects. This framework places stringent constraints on the possible types of symmetry fractionalization that can occur in 2D systems whose unit cell contains fractional spin, fractional charge, or a projective representation of the symmetry group. As a concrete application, we determine when a topological phase must possess a “spinon” excitation, even in cases when spin rotational invariance is broken down to a discrete subgroup by the crystal structure. We also describe the phenomena of “anyonic spin-orbit coupling,” which may arise from the interplay of translational and on-site symmetries. These include the possibility of on-site symmetry defect branch lines carrying topological charge per unit length and lattice dislocations inducing degeneracies protected by on-site symmetry.

  19. Finite Element Analysis of the Effect of Proximal Contour of Class II Composite Restorations on Stress Distribution

    Directory of Open Access Journals (Sweden)

    Hossein Abachizadeh

    2012-09-01

    Full Text Available Introduction: The aim of this study was to evaluate the effect of proximal contour of class II composite restorations placed with straight or contoured matrix band using composite resins with different modulus of elasticity on stress distribution by finite element method. Methods: In order to evaluate the stress distribution of class II composite restorations using finite element method, upper right first molar and second premolar were modeled. Proximal boxes were designed and restored with universal Z250 and packable P60 composite resins (3M ESPE using two matrix systems: flat Tofflemire matrix and precurved sectional matrix. Finally models were evaluated under loads of 200 and 400 Newton at 90 degrees angle and the results were graphically illustrated in the form of Von Misses stresses. Results: In general the stress obtained under 400 Newton load was significantly greater than the stress of models under 200 Newton load. Von Misses stress distribution pattern of two different Z250 and P60 composites were very similar in all modes of loading and proximal contour. In all analyzed models there was a significant difference between models restored with Tofflemire matrix with flat contour and models restored with sectional matrix with curved contour. This difference was greater in first molar than second premolar. Conclusion: Use of a contoured matrix band results in less stress in class II composite resin restorations.

  20. The Broken Symmetry of Time

    International Nuclear Information System (INIS)

    Kastner, Ruth E.

    2011-01-01

    This paper seeks to clarify features of time asymmetry in terms of symmetry breaking. It is observed that, in general, a contingent situation or event requires the breaking of an underlying symmetry. The distinction between the universal anisotropy of temporal processes and the irreversibility of certain physical processes is clarified. It is also proposed that the Transactional Interpretation of quantum mechanics offers an effective way to explain general thermodynamic asymmetry in terms of the time asymmetry of radiation, where prior such efforts have fallen short.

  1. The Broken Symmetry of Time

    Science.gov (United States)

    Kastner, Ruth E.

    2011-11-01

    This paper seeks to clarify features of time asymmetry in terms of symmetry breaking. It is observed that, in general, a contingent situation or event requires the breaking of an underlying symmetry. The distinction between the universal anisotropy of temporal processes and the irreversibility of certain physical processes is clarified. It is also proposed that the Transactional Interpretation of quantum mechanics offers an effective way to explain general thermodynamic asymmetry in terms of the time asymmetry of radiation, where prior such efforts have fallen short.

  2. From physical symmetries to emergent gauge symmetries

    International Nuclear Information System (INIS)

    Barceló, Carlos; Carballo-Rubio, Raúl; Di Filippo, Francesco; Garay, Luis J.

    2016-01-01

    Gauge symmetries indicate redundancies in the description of the relevant degrees of freedom of a given field theory and restrict the nature of observable quantities. One of the problems faced by emergent theories of relativistic fields is to understand how gauge symmetries can show up in systems that contain no trace of these symmetries at a more fundamental level. In this paper we start a systematic study aimed to establish a satisfactory mathematical and physical picture of this issue, dealing first with abelian field theories. We discuss how the trivialization, due to the decoupling and lack of excitation of some degrees of freedom, of the Noether currents associated with physical symmetries leads to emergent gauge symmetries in specific situations. An example of a relativistic field theory of a vector field is worked out in detail in order to make explicit how this mechanism works and to clarify the physics behind it. The interplay of these ideas with well-known results of importance to the emergent gravity program, such as the Weinberg-Witten theorem, are discussed.

  3. The Symmetry of Multiferroics

    OpenAIRE

    Harris, A. Brooks

    2006-01-01

    This paper represents a detailed instruction manual for constructing the Landau expansion for magnetoelectric coupling in incommensurate ferroelectric magnets. The first step is to describe the magnetic ordering in terms of symmetry adapted coordinates which serve as complex valued magnetic order parameters whose transformation properties are displayed. In so doing we use the previously proposed technique to exploit inversion symmetry, since this symmetry had been universally overlooked. Havi...

  4. Symmetries of noncommutative scalar field theory

    International Nuclear Information System (INIS)

    De Goursac, Axel; Wallet, Jean-Christophe

    2011-01-01

    We investigate symmetries of the scalar field theory with a harmonic term on the Moyal space with the Euclidean scalar product and general symplectic form. The classical action is invariant under the orthogonal group if this group acts also on the symplectic structure. We find that the invariance under the orthogonal group can also be restored at the quantum level by restricting the symplectic structures to a particular orbit.

  5. Approximate and renormgroup symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Ibragimov, Nail H. [Blekinge Institute of Technology, Karlskrona (Sweden). Dept. of Mathematics Science; Kovalev, Vladimir F. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Mathematical Modeling

    2009-07-01

    ''Approximate and Renormgroup Symmetries'' deals with approximate transformation groups, symmetries of integro-differential equations and renormgroup symmetries. It includes a concise and self-contained introduction to basic concepts and methods of Lie group analysis, and provides an easy-to-follow introduction to the theory of approximate transformation groups and symmetries of integro-differential equations. The book is designed for specialists in nonlinear physics - mathematicians and non-mathematicians - interested in methods of applied group analysis for investigating nonlinear problems in physical science and engineering. (orig.)

  6. Approximate and renormgroup symmetries

    International Nuclear Information System (INIS)

    Ibragimov, Nail H.; Kovalev, Vladimir F.

    2009-01-01

    ''Approximate and Renormgroup Symmetries'' deals with approximate transformation groups, symmetries of integro-differential equations and renormgroup symmetries. It includes a concise and self-contained introduction to basic concepts and methods of Lie group analysis, and provides an easy-to-follow introduction to the theory of approximate transformation groups and symmetries of integro-differential equations. The book is designed for specialists in nonlinear physics - mathematicians and non-mathematicians - interested in methods of applied group analysis for investigating nonlinear problems in physical science and engineering. (orig.)

  7. Pseudo Jahn–Teller effect in distortion and restoration of planar configurations of tetra-heterocyclic 1,2-diazetes C{sub 2}N{sub 2}E{sub 4}, E = H, F, Cl, Br

    Energy Technology Data Exchange (ETDEWEB)

    Ilkhani, Ali R. [Institute for Theoretical Chemistry, University of Texas at Austin, Austin, TX 78712 (United States); Department of Chemistry, Yazd Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of); Gorinchoy, Natalia N. [Institute of Chemistry, Academy of Sciences of Moldova, Chisinau, Republic of Moldova (Moldova, Republic of); Bersuker, Isaac B., E-mail: bersuker@cm.utexas.edu [Institute for Theoretical Chemistry, University of Texas at Austin, Austin, TX 78712 (United States); Institute of Chemistry, Academy of Sciences of Moldova, Chisinau, Republic of Moldova (Moldova, Republic of)

    2015-10-16

    Highlights: • The pseudo Jahn–Teller mechanism of puckering of tetracyclic 1,2-diazetes is revealed. • Vibronic constants are extracted from ab initio calculations versus PJTE equations. • Methods of restoring the planar configuration by external perturbations are suggested. - Abstract: The pseudo Jahn–Teller effect (PJTE) is employed to explain the origin of the puckered structures of tetra-heterocyclic 1,2-diazetes, C{sub 2}N{sub 2}E{sub 4}, E = H, F, Cl, Br, and to reveal the conditions of restoration of their planar configuration. The high-symmetry C{sub 2v} planar configuration of all these compounds is unstable with respect to puckering, a{sub 2}-type distortions produced by the PJT coupling between their ground {sup 1}A{sub 1} and excited {sup 1}A{sub 2} electronic states. The PJTE coupling constants are estimated by fitting ab initio calculated energy profiles to the formulas of the vibronic coupling problem (A{sub 1} + A{sub 2}) ⊗ a{sub 2}. The conditions for the restoration of the planar configurations of the C{sub 2}N{sub 2}E{sub 4} cycles were revealed: the PJTE can be quenched by removing the outer two electrons, e.g. by producing a “triple-decker sandwich” structure with two electron acceptors on both sides of the neutral cycle.

  8. Effects of eradication and restoration treatments on Italian thistle (Carduus pycnocephalus)

    Science.gov (United States)

    McGinnis, Thomas; Keeley, Jon

    2011-01-01

    Low elevation grasslands in California long have been dominated by Mediterranean grasses, but many areas still have large native forb populations. Alien forbs invade these grasslands, displacing both native and other alien species. Italian thistle is a noxious alien herb that has recently invaded these grasslands, including ungrazed blue oak (Quercus douglassii) and interior live oak (Quercus wislizenii) stands in Sequoia National Park. Here, Italian thistle tends to dominate under oaks and has the potential to substantially alter the foothill ecosystem by displacing native plants and acting as a ladder fuel that can carry fires into the oak canopy. We tested the effects of selectively reducing Italian thistle populations alone and in combination with restoration of native species. Two thistle eradication techniques (clipping and the application of clopyralid herbicide) and two restoration techniques (addition of native forb seeds or planting native grass plugs) were used. After two consecutive years of treatment we found: a) clipping was not effective at reducing Italian thistle populations (clipping reduced Italian thistle density in some areas, but not vegetative cover), b) herbicide reduced both Italian thistle density and vegetative cover for the first two growing seasons after application, but cover rebounded in the third growing season, c) native forb cover and species richness were not significantly affected by clipping or spot-treating with herbicide, d) the grass and forb addition treatments by themselves were not effective at reducing Italian thistle during the course of this study and e) sowing annual forb seeds after clipping resulted in greater forb cover and moderately reduced Italian thistle vegetative cover in the short term.

  9. Flood effects on an Alaskan stream restoration project: the value of long-term monitoring

    Science.gov (United States)

    Densmore, Roseann V.; Karle, Kenneth F.

    2009-01-01

    On a nationwide basis, few stream restoration projects have long-term programs in place to monitor the effects of floods on channel and floodplain configuration and floodplain vegetation, but long-term and event-based monitoring is required to measure the effects of these stochastic events and to use the knowledge for adaptive management and the design of future projects. This paper describes a long-term monitoring effort (15 years) on a stream restoration project in Glen Creek in Denali National Park and Preserve in Alaska. The stream channel and floodplain of Glen Creek had been severely degraded over a period of 80 years by placer mining for gold, which left many reaches with unstable and incised streambeds without functioning vegetated floodplains. The objectives of the original project, initiated in 1991, were to develop and test methods for the hydraulic design of channel and floodplain morphology and for floodplain stabilization and riparian habitat recovery, and to conduct research and monitoring to provide information for future projects in similar degraded watersheds. Monitoring methods included surveyed stream cross-sections, vegetation plots, and aerial, ground, and satellite photos. In this paper we address the immediate and outlying effects of a 25-year flood on the stream and floodplain geometry and riparian vegetation. The long-term monitoring revealed that significant channel widening occurred following the flood, likely caused by excessive upstream sediment loading and the fairly slow development of floodplain vegetation in this climate. Our results illustrated design flaws, particularly in regard to identification and analysis of sediment sources and the dominant processes of channel adjustment.

  10. Broken color symmetry and weak currents

    International Nuclear Information System (INIS)

    Stech, B.

    1976-01-01

    Broken colour symmetry predicts a very rich spectrum of new particles. If broken colour is relevant at all, charged psi-particles should be found in particular at the 4 GeV region. For the weak hadronic currents no completely satisfactory suggestion exists. Broken colour symmetry describes qualitatively several of the new effects observed recently. (BJ) [de

  11. Effects of hydrogen peroxide bleaching strip gels on dental restorative materials in vitro: surface microhardness and surface morphology.

    Science.gov (United States)

    Duschner, Heinz; Götz, Hermann; White, Donald J; Kozak, Kathleen M; Zoladz, James R

    2004-01-01

    This study examined the effects of peroxide tooth bleaching, including Crest Whitestrips hydrogen peroxide gel treatments, on the surface hardness and morphology of common dental restorative treatments. American Dental Association (ADA) recommended dental restorative materials, including amalgam, dental gold, porcelain, glass ionomer, and composites, were prepared according to manufacturers' instructions. A cycling treatment methodology was employed which alternated ex vivo human salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching treatments included commercial Crest Whitestrips bleaching gels, which utilize hydrogen peroxide as the in situ bleaching source, and several commercial carbamide peroxide bleaching gels. Control treatments included placebo gels and an untreated group. Crest Whitestrips bleaching included treatment exposures simulating recommended clinical exposures (14 hours), along with excess bleaching simulating exposure to five times suggested Crest Whitestrips use. At the conclusion of treatments, surface microhardness measures and surface morphological assessments with standard and variable pressure (VP-) SEMs were conducted to assess the effects of bleaching exposure on the surface morphology and structural integrity of the restoratives. Surface microhardness and SEM measures revealed no significant deleterious effects on the restoration surfaces from Whitestrips gels. These results confirm that tooth bleaching from the selected commercial hydrogen peroxide or carbamide peroxide bleaching systems does not produce changes in surface morphology or microhardness of common dental restorative materials. These results support the clinical safety of the selected commercial bleaching systems to the oral environment, matching results obtained from long-term use of these ingredients applied in dental offices and available in commercial formulations.

  12. Effect of restoration volume on stresses in a mandibular molar: a finite element study.

    Science.gov (United States)

    Wayne, Jennifer S; Chande, Ruchi; Porter, H Christian; Janus, Charles

    2014-10-01

    There can be significant disagreement among dentists when planning treatment for a tooth with a failing medium-to-large--sized restoration. The clinician must determine whether the restoration should be replaced or treated with a crown, which covers and protects the remaining weakened tooth structure during function. The purpose of this study was to evaluate the stresses generated in different sized amalgam restorations via a computational modeling approach and reveal whether a predictable pattern emerges. A computer tomography scan was performed of an extracted mandibular first molar, and the resulting images were imported into a medical imaging software package for tissue segmentation. The software was used to separate the enamel, dentin, and pulp cavity through density thresholding and surface rendering. These tissue structures then were imported into 3-dimensional computer-aided design software in which material properties appropriate to the tissues in the model were assigned. A static finite element analysis was conducted to investigate the stresses that result from normal occlusal forces. Five models were analyzed, 1 with no restoration and 4 with increasingly larger restoration volume proportions: a normal-sized tooth, a small-sized restoration, 2 medium-sized restorations, and 1 large restoration as determined from bitewing radiographs and occlusal surface digital photographs. The resulting von Mises stresses for dentin-enamel of the loaded portion of the tooth grew progressively greater as the size of the restoration increased. The average stress in the normal, unrestored tooth was 4.13 MPa, whereas the smallest restoration size increased this stress to 5.52 MPa. The largest restoration had a dentin-enamel stress of 6.47 MPa. A linear correlation existed between restoration size and dentin-enamel stress, with an R(2) of 0.97. A larger restoration volume proportion resulted in higher dentin-enamel stresses under static loading. A comparison of the von Mises

  13. Restorative Effects of Caffeic Acid Phenethyl Ester in Radiation-Induced Oxidative Hepatic Disorders

    International Nuclear Information System (INIS)

    El-Fatih, N.M.; EI-Tawil, G.A.

    2009-01-01

    The potential role of antioxidant natural phenolic compounds in the prevention of oxidative tissue-damage associated with ionizing-radiation has accumulated over the past decades. The possible restorative effect of caffeic acid phenethyl ester (CAPE) in minimizing radiation-induced hepatic injury in male albino rats was investigated. CAPE was given to rats via intraperitoneal (ip.) injection at a dose of (10μmol/ kg b.wt.) for 21 successive days throughout exposure to gamma radiation and continued for 15 successive days post gamma-radiation exposure. Whole body gamma-irradiation was delivered as fractionated doses (3 weeks) 2 Gy increment every week up to total cumulative dose of G Gy. Rats were sacrificed at either I, or 15 days after last dose of radiation. Malondialdehyde (MDA) content was determined in plasma and hepatic tissues. In addition, the activities of xanthine oxidase (XO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) as well as the level of reduced glutathione (GSH) were determined to evaluate the changes of antioxidant-status in blood systems and hepatic tissues. Meantime, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activities were estimated in rat serum. Results showed that exposure to gamma-radiation significantly increased the MDA levels and the activities of XO, ALT, AST and ALP. Moreover, SOD, CAT and GSH-Px activities as well GSH contents showed significant consumption in irradiated rats. Treatment with CAPE showed a significant decrease in MDA level and caused significant increases in all enzymes measured in hepatic tissues and blood systems when compared with irradiated group. Conclusion: radiation-exposure leads to a reduction in antioxidant enzymatic activities and causes lipid peroxidation in hepatic tissues and blood. Under experimental condition, CAPE exhibits restorative effects on gamma-rays-induced hepatic-oxidative impairment in rats

  14. Restorative Effects of Caffeic Acid Phenethyl Ester in Radiation-Induced Oxidative Hepatic Disorders

    International Nuclear Information System (INIS)

    El-Fatih, N.M.; EI-Tawil, G.A.

    2008-01-01

    The potential role of antioxidant natural phenolic compounds in the prevention of oxidative tissue-damage associated with ionizing-radiation has accumulated over the past decades. The possible restorative effect of caffeic acid phenethyl ester (CAPE) in minimizing radiation-induced hepatic injury in male albino rats was investigated. CAPE was given to rats via intraperitoneal (ip.) injection at a dose of (10μmol/ kg b.wt.) for 21 successive days throughout exposure to gamma radiation and continued for 15 successive days post gamma-radiation exposure. Whole body gamma-irradiation was delivered as fractionated doses (3 weeks) 2 Gy increment every week up to total cumulative dose of G Gy. Rats were sacrificed at either I, or 15 days after last dose of radiation. Malondialdehyde (MDA) content was determined in plasma and hepatic tissues. In addition, the activities of xanthine oxidase (XO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) as well as the level of reduced glutathione (GSH) were determined to evaluate the changes of antioxidant-status in blood systems and hepatic tissues. Meantime, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activities were estimated in rat serum. Results showed that exposure to gamma-radiation significantly increased the MDA levels and the activities of XO, ALT, AST and ALP. Moreover, SOD, CAT and GSH-Px activities as well GSH contents showed significant consumption in irradiated rats. Treatment with CAPE showed a significant decrease in MDA level and caused significant increases in all enzymes measured in hepatic tissues and blood systems when compared with irradiated group. Conclusion: radiation-exposure leads to a reduction in antioxidant enzymatic activities and causes lipid peroxidation in hepatic tissues and blood. Under experimental condition, CAPE exhibits restorative effects on gamma-rays-induced hepatic-oxidative impairment in rats

  15. Assessment of the Effect of Orthodontic Treatment on the Periodontal Health of Endodontically Restored Tooth.

    Science.gov (United States)

    Jalaluddin, Md; Goyal, Vinod; Naqvi, Zuber A; Gupta, Bhaskar; Asnani, Mohil M; Sonigra, Hitesh M

    2017-07-01

    Intorduction: Patients usually undergo orthodontic treatment for achieving ideal interocclusal relationship between the dental tissue and bony tissue along with improving the speech, mastication, and facial esthetic appearance. Literature quotes paucity in the studies evaluating the effect of orthodontic treatment on the periodontal health of endodontically treated teeth. Hence, we planned the present study to assess the effect of orthodontic treatment on the periodontal health of endodonti-cally restored tooth. The present study included assessment of 80 patients who underwent orthodontic treatment. All the patients were divided broadly into two study groups: groups I and II. Group I included patients with the absence of endodontically treated teeth, while group II included patients which maxillary central incisors were resorted endodontically. Examination of the periodontal health of the patients was done using the community periodontal index of treatment need (CPITN) around the selected teeth. All the values were recorded during the preorthodontic time, postorthodontic time, and after the first 6 months of starting of the orthodontic treatment. All the results were recorded separately and analyzed. In the groups I and II, 28 and 25 patients respectively, had score of 1, while 10 patients in group I and 12 patients in group II had score of 2. Nonsignificant results were obtained while comparing the CPITN score in between the two study groups when measured at the pre-, intra-, and postortho time. In patients undergoing orthodontic treatment, having endodontically resorted teeth, no difference exists in relation to the periodontal health. Orthodontic treatment can be safely carried in patients with endodontically restored teeth.

  16. More on ghost condensation in Yang-Mills theory: BCS versus Overhauser effect and the breakdown of the Nakanishi-Ojima annex SL(2,R) symmetry

    International Nuclear Information System (INIS)

    Dudal, David; Verschelde, Henri; Lemes, Vitor E.R.; Sarandy, Marcelo S.; Sorella, Silvio P.; Picariello, Marco; Vicini, Alessandro; Gracey, John A.

    2003-01-01

    We analyze the ghost condensates abc c b c c >, abc c-bar b c-bar c > and abc c-barbc c > in Yang-Mills theory in the Curci-Ferrari gauge. By combining the local composite operator formalism with the algebraic renormalization technique, we are able to give a simultaneous discussion of abc c b c c >, abc c-bar b c-bar c > and abc c-bar b c c >, which can be seen as playing the role of the BCS, respectively Overhauser effect in ordinary superconductivity. The Curci-Ferrari gauge exhibits a global continuous symmetry generated by the Nakanishi-Ojima (NO) algebra. This algebra includes, next to the {(anti-)BRST} transformation, a SL(2,R) subalgebra. We discuss the dynamical symmetry breaking of the NO algebra through these ghost condensates. Particular attention is paid to the Landau gauge, a special case of the Curci-Ferrari gauge. (author)

  17. Class II glass ionomer/silver cermet restorations and their effect on interproximal growth of mutans streptococci.

    Science.gov (United States)

    Berg, J H; Farrell, J E; Brown, L R

    1990-02-01

    The release of fluoride from glass ionomer materials is one of the most important features of this newly implemented material, and the remineralization effects of this phenomenon have been documented (Hicks and Silverstone 1986). This paper examines the effects of glass ionomer/silver cermet restorations on the plaque levels of interproximal mutans streptococci. Fifteen patients with Class II lesions in primary molars were selected for study. Interproximal plaque samples were obtained from each of the lesion sites and from one caries-free site approximal to a primary molar. One lesion was restored with composite resin to serve as a treated control to the glass ionomer/silver cermet (Ketac Silver, ESPE/Premier Sales Corp., Norristown, Pennsylvania) test site. A sound (unaltered) interproximal site served as the untreated control site. Plaque samples were collected before and at one week, one month, and three months post-treatment. Samples were serially diluted to enable colony counts of mutans streptococci. One week post-treatment counts showed that the glass ionomer/silver cermet restorations significantly reduced (P less than 0.05) the approximal plaque levels of mutans streptococci. Conversely, the untreated and treated control sites did not exhibit reductions in approximal plaque levels of mutans streptococci. These results indicate that glass ionomer restorations may be inhibitory to the growth of mutans streptococci in dental plaque approximal to this restorative material in the primary dentition.

  18. Summary: Symmetries and spin

    International Nuclear Information System (INIS)

    Haxton, W.C.

    1988-01-01

    I discuss a number of the themes of the Symmetries and Spin session of the 8th International Symposium on High Energy Spin Physics: parity nonconservation, CP/T nonconservation, and tests of charge symmetry and charge independence. 28 refs., 1 fig

  19. Symmetry Festival 2016

    CERN Document Server

    2016-01-01

    The Symmetry Festival is a science and art program series, the most important periodic event (see its history) to bring together scientists, artists, educators and practitioners interested in symmetry (its roots, what is behind, applications, etc.), or in the consequences of its absence.

  20. Quantum symmetry for pedestrians

    International Nuclear Information System (INIS)

    Mack, G.; Schomerus, V.

    1992-03-01

    Symmetries more general than groups are possible in quantum therory. Quantum symmetries in the narrow sense are compatible with braid statistics. They are theoretically consistent much as supersymmetry is, and they could lead to degenerate multiplets of excitations with fractional spin in thin films. (orig.)

  1. Wigner's Symmetry Representation Theorem

    Indian Academy of Sciences (India)

    IAS Admin

    At the Heart of Quantum Field Theory! Aritra Kr. ... principle of symmetry was not held as something very fundamental ... principle of local symmetry: the laws of physics are invariant un- .... Next, we would show that different coefficients of a state ...

  2. Charged fluids with symmetries

    Indian Academy of Sciences (India)

    It is possible to introduce many types of symmetries on the manifold which restrict the ... metric tensor field and generate constants of the motion along null geodesics .... In this analysis we have studied the role of symmetries for charged perfect ...

  3. Symmetry and Interculturality

    Science.gov (United States)

    Marchis, Iuliana

    2009-01-01

    Symmetry is one of the fundamental concepts in Geometry. It is a Mathematical concept, which can be very well connected with Art and Ethnography. The aim of the article is to show how to link the geometrical concept symmetry with interculturality. For this mosaics from different countries are used.

  4. A pseudogap model beyond BCS for the cuprates: The effect of order parameter symmetry, Debye frequency and band structure

    International Nuclear Information System (INIS)

    Rodriguez-Nunez, J.J.; Schmidt, A.A.; Beck, H.; Valera, M.

    2005-08-01

    One of the most intriguing aspects of high temperature superconductors (HTSC) is the presence of the pseudogap in the normal and the superconducting phases of the cuprate compounds. Several pseudogap models have been proposed to explain the $abnormal$ properties of the cuprates. One of the recent models relies on the assumption that the self-energy is given by Σ PG (iω n )=- E g 2 (k)G 0 (k,-iω n ) where G 0 (k,iω n is the one- particle free Green function. Going beyond this mean field model for the pseudogap we now take into account fluctuations of the pseudogap as Σ PG (iω n )=- E g 2 (k)G PG (k,-iω n ) where G PG (k,iω n is the one-particle full Green function. We study the combined effect of the band structure and the Debye frequency, ω D , on the superconducting critical temperature, T c , as a function of the number of carriers per site, n. Our conclusions are: 1) increasing the value of V/t increases the value of T c /t; 2) increasing the value of E G /t decreases the value of T c /t. By the way, one needs some critical value of V/t to have finite values of T c /t. This is the reason we have taken high values of V/ to find superconductivity; 3) decreasing the value of ω D /t decreases the value of T c /t. This is reasonable since we have less available states around the Fermi; 4) the inclusion of α', which we call the effect of the band structure, is important because it moves the center of curve of T c /t x n. The center of this curve, with respect to half-filling (n=1), is displaced to the left if α'>0.0; 5) the chemical potential is defined in the region where T c /t ≠ 0. However, in this region, it is almost identical for different values of V/t. This is due to the fact that μ is a global property; 6) our model always produces d-wave superconductivity around the Fermi level, independent whether E G (K-bar)/t is s- or d-wave symmetry. (author)

  5. Symmetry and symmetry breaking in modern physics

    International Nuclear Information System (INIS)

    Barone, M; Theophilou, A K

    2008-01-01

    In modern physics, the theory of symmetry, i.e. group theory, is a basic tool for understanding and formulating the fundamental principles of Physics, like Relativity, Quantum Mechanics and Particle Physics. In this work we focus on the relation between Mathematics, Physics and objective reality

  6. Effects of restoration measures on plant communities of wet heathland ecosystems

    NARCIS (Netherlands)

    Jansen, AJM; Fresco, LFM; Grootjans, AP; Jalink, Mark H.; Rapson, G.

    2004-01-01

    Question: Which are the success and failure of restoration measures, particularly sod-cutting and hydrological measures, in small wetlands on mineral soils in The Netherlands. Location: Twente. in the eastern part of The Netherlands. Methods: Success or failure of restoration measures has been

  7. Effects of restoration measures on plant communities of wet heathland ecosystems

    NARCIS (Netherlands)

    Jansen, AJM; Fresco, LFM; Grootjans, AP; Jalink, Mark H.; Rapson, G.

    Question: Which are the success and failure of restoration measures, particularly sod-cutting and hydrological measures, in small wetlands on mineral soils in The Netherlands. Location: Twente. in the eastern part of The Netherlands. Methods: Success or failure of restoration measures has been

  8. Effects of restoration measures on plant communities of wet heathland ecosystems

    NARCIS (Netherlands)

    Jansen, A.J.M.; Fresco, L.F.M.; Grootjans, A.P.; Jalink, M.H.

    2004-01-01

    Question: Which are the success and failure of restoration measures, particularly sod-cutting and hydrological measures, in small wetlands on mineral soils in The Netherlands. Location: Twente, in the eastern part of The Netherlands. Methods: Success or failure of restoration measures has been

  9. Collaborative restoration effects on forest structure in ponderosa pine-dominated forests of Colorado

    Science.gov (United States)

    Jeffery B. Cannon; Kevin J. Barrett; Benjamin M. Gannon; Robert N. Addington; Mike A. Battaglia; Paula J. Fornwalt; Gregory H. Aplet; Antony S. Cheng; Jeffrey L. Underhill; Jennifer S. Briggs; Peter M. Brown

    2018-01-01

    In response to large, severe wildfires in historically fire-adapted forests in the western US, policy initiatives, such as the USDA Forest Service’s Collaborative Forest Landscape Restoration Program (CFLRP), seek to increase the pace and scale of ecological restoration. One required component of this program is collaborative adaptive management, in which monitoring...

  10. Restoring big sagebrush after controlling encroaching western juniper with fire: aspect and subspecies effects

    Science.gov (United States)

    The need for restoration of shrubs is increasingly recognized around the world. In the western USA, restoration of mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) after controlling encroaching conifers is a priority to improve sagebrush-associated wildlife habitat. ...

  11. Effect of dental restoration with epoxy and bioceramic paste on periodontal tissue damage

    Institute of Scientific and Technical Information of China (English)

    Nan-Lin Meng

    2017-01-01

    Objective:To study the effect of dental restoration with epoxy and bioceramic paste on periodontal tissue damage.Methods: Patients with pulpal and periapical diseases who received root canal therapy in our hospital between May 2013 and October 2016 were retrospectively analyzed, and according to the different root canal filling materials they used, they were divided into epoxy group and bioceramic group who used epoxy paste and bioceramic paste as root canal filling materials respectively. Before and after treatment, gingival crevicular fluid was collected respectively to determine the levels of inflammatory factors, oxidative stress products, cell apoptosis molecules and protease-related molecules.Results: 2 weeks after treatment, IL-1β, IL-6, CRP, ROS, MDA, AOPP, Bcl-2, Bax, Cyt-C, caspase-3, Smac, EMMPRIN, MMP-1, MMP-2, TIMP-1 and TIMP-2 levels in gingival crevicular fluid of epoxy group were not significantly different from those before treatment; IL-1β, IL-6, CRP, ROS, MDA, AOPP, Bax, Cyt-C, caspase-3, Smac, EMMPRIN, MMP-1 and MMP-2 levels in gingival crevicular fluid of bioceramic group were significantly higher than those before treatment while Bcl-2, TIMP-1 and TIMP-2 levels were significantly lower than those before treatment; IL-1β, IL-6, CRP, ROS, MDA, AOPP, Bcl-2, Bax, Cyt-C, caspase-3, Smac, EMMPRIN, MMP-1, MMP-2, TIMP-1 and TIMP-2 levels in gingival crevicular fluid were significantly different between two groups of patients after treatment.Conclusion:Epoxy paste for dental restoration causes less damage to periodontal tissue than bioceramic paste.

  12. Effect of dental restoration with epoxy and bioceramic paste on periodontal tissue damage

    Directory of Open Access Journals (Sweden)

    Nan-Lin Meng

    2017-05-01

    Full Text Available Objective: To study the effect of dental restoration with epoxy and bioceramic paste on periodontal tissue damage. Methods: Patients with pulpal and periapical diseases who received root canal therapy in our hospital between May 2013 and October 2016 were retrospectively analyzed, and according to the different root canal filling materials they used, they were divided into epoxy group and bioceramic group who used epoxy paste and bioceramic paste as root canal filling materials respectively. Before and after treatment, gingival crevicular fluid was collected respectively to determine the levels of inflammatory factors, oxidative stress products, cell apoptosis molecules and protease-related molecules. Results: 2 weeks after treatment, IL-1β, IL-6, CRP, ROS, MDA, AOPP, Bcl-2, Bax, Cyt-C, caspase-3, Smac, EMMPRIN, MMP-1, MMP-2, TIMP-1 and TIMP-2 levels in gingival crevicular fluid of epoxy group were not significantly different from those before treatment; IL-1β, IL-6, CRP, ROS, MDA, AOPP, Bax, Cyt-C, caspase-3, Smac, EMMPRIN, MMP-1 and MMP-2 levels in gingival crevicular fluid of bioceramic group were significantly higher than those before treatment while Bcl-2, TIMP-1 and TIMP-2 levels were significantly lower than those before treatment; IL-1β, IL-6, CRP, ROS, MDA, AOPP, Bcl-2, Bax, Cyt-C, caspase-3, Smac, EMMPRIN, MMP-1, MMP-2, TIMP-1 and TIMP-2 levels in gingival crevicular fluid were significantly different between two groups of patients after treatment. Conclusion: Epoxy paste for dental restoration causes less damage to periodontal tissue than bioceramic paste.

  13. Effectiveness of benzocaine in reducing deep cavity restoration and post-extraction stress in dental patients

    Directory of Open Access Journals (Sweden)

    Khalid H. Al-Samadani

    2015-11-01

    Full Text Available Objectives: To investigate the effectiveness of topical anesthetic, 20% benzocaine in relieving pain and stress in patients following deep cavity restoration and extraction of teeth under local anesthesia (LA. Methods: A prospective clinical trial was conducted from October 2014 until April 2015 at Taibah University, Al Madinah Al Munawarah, Kingdom of Saudi Arabia. Forty-five patients were included in the 20% benzocaine group, and 46 in the normal saline group. Evaluation of the dental stress was made pre-operatively and immediately post-operative treatment using the visual analogue scale (VAS. Furthermore, discomfort of the injections were recorded by the patients after each treatment on standard 100 mm VAS, tagged at the endpoints with “no pain” (0 mm and “unbearable pain” (100 mm. Results: There were statistically significant differences between the mean stress scores for patients in the benzocaine and normal saline groups post-operatively (p=0.002. There were significant differences between the mean pain scores for patients in the post buccal injection (p=0.001, post palatal injection (p=0.01, and the post inferior alveolar nerve block groups (p=0.02. Buccal, palatal, and inferior alveolar nerve block injections were more painful for patients in the normal saline group than the benzocaine group. Conclusion: This investigation has demonstrated that post-operative stress associated with deep cavity restoration and dental extractions under LA can be reduced by the application of topical anesthetic (20% benzocaine at the operative site for intra-oral injections.

  14. Nature versus nurture: functional assessment of restoration effects on wetland services using Nuclear Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Sundareshwar, P.V.; Richardson, C.J.; Gleason, R.A.; Pellechia, P.J.; Honomichl, S.

    2009-01-01

    Land-use change has altered the ability of wetlands to provide vital services such as nutrient retention. While compensatory practices attempt to restore degraded wetlands and their functions, it is difficult to evaluate the recovery of soil biogeochemical functions that are critical for restoration of ecosystem services. Using solution 31P Nuclear Magnetic Resonance Spectroscopy, we examined the chemical forms of phosphorus (P) in soils from wetlands located across a land-use gradient. We report that soil P diversity, a functional attribute, was lowest in farmland, and greatest in native wetlands. Soil P diversity increased with age of restoration, indicating restoration of biogeochemical function. The trend in soil P diversity was similar to documented trends in soil bacterial taxonomic composition but opposite that of soil bacterial diversity at our study sites. These findings provide insights into links between ecosystem structure and function and provide a tool for evaluating the success of ecosystem restoration efforts. Copyright 2009 by the American Geophysical Union.

  15. Relativistic effect of pseudospin symmetry and tensor coupling on the Mie-type potential via Laplace transformation method

    International Nuclear Information System (INIS)

    Eshghi, M.; Ikhdair, S. M.

    2014-01-01

    A relativistic Mie-type potential for spin-1/2 particles is studied. The Dirac Hamiltonian contains a scalar S(r) and a vector V(r) Mie-type potential in the radial coordinates, as well as a tensor potential U(r) in the form of Coulomb potential. In the pseudospin (p-spin) symmetry setting Σ = C ps and Δ = V(r), an analytical solution for exact bound states of the corresponding Dirac equation is found. The eigenenergies and normalized wave functions are presented and particular cases are discussed with any arbitrary spin—orbit coupling number κ. Special attention is devoted to the case Σ = 0 for which p-spin symmetry is exact. The Laplace transform approach (LTA) is used in our calculations. Some numerical results are obtained and compared with those of other methods. (general)

  16. Symmetry Aspects of Dislocation-Effected Crystal Properties: Material Strength Levels and X-ray Topographic Imaging

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2014-03-01

    Full Text Available Several materials science type research topics are described in which advantageous use of crystal symmetry considerations has been helpful in ferreting the essential elements of dislocation behavior in determining material properties or for characterizing crystal/polycrystalline structural relationships; for example: (1 the mechanical strengthening produced by a symmetrical bicrystal grain boundary; (2 cleavage crack formation at the intersection within a crystal of symmetrical dislocation pile-ups; (3 symmetry aspects of anisotropic crystal indentation hardness measurements; (4 X-ray diffraction topography imaging of dislocation strains and subgrain boundary misorientations; and (5 point and space group aspects of twinning. Several applications are described in relation to the strengthening of grain boundaries in nanopolycrystals and of multiply-oriented crystal grains in polysilicon photovoltaic solar cell materials. A number of crystallographic aspects of the different topics are illustrated with a stereographic method of presentation.

  17. Effects of the nuclear symmetry energy on gravitational waves from the axial W-modes of isolated neutron stars

    International Nuclear Information System (INIS)

    Wen, Dehua; Li, Baoan; Krastev, P.G.

    2010-01-01

    The frequencies and damping times of the axial w-mode oscillations of neutron stars are investigated using a nuclear equation of state (EOS) partially constrained by the available terrestrial laboratory data. It is found that the nuclear symmetry energy E sym (ρ), especially its high density behavior, plays an important role in determining both the eigen-frequencies and the damping times of these oscillations. (author)

  18. Effect of Different Surface Treatments on the Bond Strength of Repaired Resin Restorations

    International Nuclear Information System (INIS)

    Engy Fahmy Ismaiel Fekry Abaza

    2010-01-01

    In the last decade, growing demands by patients for mercury-free esthetic restorations had markedly increased the use of resin composites in restorative dentistry. However, despite the continuing development of resin composites with improved properties, several factors, such as discoloration, color mismatch, wear; chipping or bulk fracture might present clinical problems (Mjor and Gordan. 2002, Vichi et al. 2004 and Kolbeck et al. 2006). As a result, the clinician should decide whether to replace or simply repair these restorations. Total replacement of the restoration might be regarded as over-treatment since in most cases, large portions of the restorations might be clinically and radio graphically considered free of failure. Moreover, complete removal of the restoration inevitably resulted in weakening of the tooth, unnecessary removal of intact dental tissues, more money and time consuming. For these reasons, the repair of the restoration instead of its removal would be a favorable procedure (Lucena-Martin et al. 2001, Frankenberger et al. 2003 a and Oztas et al. 2003). The key element in the determination of successful repair procedures was the adequate bond strength between the existing resin composite and the new one. Various methods have been suggested to improve the bond strength of the repaired resin restorations (Tezvergil et al. 2003 and Bonstein et al. 2005). Mechanical and/or chemical treatments had been investigated for preparation of the aged resin restorations to be repaired (Tezvergil et al. 2003, Ozcan et al. 2005 and Hannig et al. 2006). These treatments were introduced to counteract the problems of aged resin restorations which were limited amount of residual free radicals available for reaction with the repair material, contaminated surface, and highly cross-linked resin matrix ( Dall Oca et al. 2006 and Papacchini et al. 2007 a) Previous studies emphasized that mechanical treatments are the most important factor in obtaining optimal repair

  19. Effect of drought stress on male fertility restoration in A3 CMS-inducing cytoplasm of sorghum

    Directory of Open Access Journals (Sweden)

    Valentin V. Kozhemyakin

    2017-08-01

    Full Text Available Use of cytoplasmic male sterility (CMS in hybrid breeding requires effective male fertility-restoring lines. In sorghum, very few restoring lines that can restore fertility in A3 CMS have been reported. To identify the reasons for this deficiency, F1 and F2 hybrids of an A3 CMS line crossed with the line IS1112C, a donor of fertility-restoring (Rf genes for A3 cytoplasm, and testcrosses of fertile plants to A3 CMS lines were grown under contrasting water availability regimes in dryland and irrigated field plots. In the irrigated plots the frequency of fertile plants in testcrosses was twice that in dryland plots (P < 0.05. Fertile plants from the F2 family grown in the irrigated plots showed significantly higher restoration ability than fertile plants from the same family grown in dryland plots. F3 plants from the F2 family grown in irrigated plots yielded on average a sixfold higher frequency of fertile plants in testcrosses than F3 plants derived from dryland plots (P < 0.01. Fertility of testcross hybrids correlated negatively with air vapor pressure deficit (VPD at flowering (r = −0.96; P < 0.01 suggesting that VPD is a trigger for downregulation of Rf genes for A3 cytoplasm.

  20. Chiral symmetry in the strong color-electric field in terms of Nambu-Jona-Lasinio model

    International Nuclear Information System (INIS)

    Suganuma, Hideo

    1990-01-01

    We examine the behavior of chiral symmetry in an external gluon field using Nambu-Jona-Lasinio model, which is an effective theory of QCD. The Dyson equation for the dynamical quark mass in the presence of the external color-electric field is obtained. By solving it in the color flux tube inside mesons, chiral symmetry would be restored in the flux tube of mesons and this result supports Chiral Bag picture for mesons. Next we consider the flux tubes formed in the central region for ultra-relativistic heavy-ion collisions, and find the chiral restoration occurs there, so that the current quark mass seems to be suitable in calculating the q-q-bar pair creation rate by the Schwinger formula in the flux-tube picture. (author)

  1. Chiral-symmetry order parameter, the lattice, and nucleosynthesis

    International Nuclear Information System (INIS)

    McLerran, L.

    1987-01-01

    I discuss an order parameter for the chiral-symmetry restoration phase transition which may be useful in computations of big-bang nucleosynthesis, a phenomenon which requires a finite baryon-number density. This parameter is strictly speaking an order parameter in the large-N limit, and distinguishes between a parity-doubled and a massless-fermion realization of chiral-symmetry restoration. This order parameter may be evaluated at a zero net baryon-number density at finite temperature, and is useful as long as the baryon chemical potential μ is much less than the temperature T

  2. Braided quantum field theories and their symmetries

    International Nuclear Information System (INIS)

    Sasai, Yuya; Sasakura, Naoki

    2007-01-01

    Braided quantum field theories, proposed by Oeckl, can provide a framework for quantum field theories that possess Hopf algebra symmetries. In quantum field theories, symmetries lead to non-perturbative relations among correlation functions. We study Hopf algebra symmetries and such relations in the context of braided quantum field theories. We give the four algebraic conditions among Hopf algebra symmetries and braided quantum field theories that are required for the relations to hold. As concrete examples, we apply our analysis to the Poincare symmetries of two examples of noncommutative field theories. One is the effective quantum field theory of three-dimensional quantum gravity coupled to spinless particles formulated by Freidel and Livine, and the other is noncommutative field theory on the Moyal plane. We also comment on quantum field theory in κ-Minkowski spacetime. (author)

  3. Superdeformations and fermion dynamical symmetries

    International Nuclear Information System (INIS)

    Wu, Cheng-Li

    1990-01-01

    In this talk, I will present a link between nuclear collective motions and their underlying fermion dynamical symmetries. In particular, I will focus on the microscopic understanding of deformations. It is shown that the SU 3 of the one major shell fermion dynamical symmetry model (FDSM) is responsible for the physics of low and high spins in normal deformation. For the recently observed phenomena of superdeformation, the physics of the problem dictates a generalization to a supershell structure (SFDSM), which also has an SU 3 fermion dynamical symmetry. Many recently discovered feature of superdeformation are found to be inherent in such an SU 3 symmetry. In both cases the dynamical Pauli effect plays a vital role. A particularly noteworthy discovery from this model is that the superdeformed ground band is not the usual unaligned band but the D-pair aligned (DPA) band, which sharply crosses the excited bands. The existence of such DPA band is a key point to understand many properties of superdeformation. Our studies also poses new experimental challenge. This is particularly interesting since there are now plans to build new and exciting γ-ray detecting systems, like the GAMMASPHERE, which could provide answers to some of these challenges. 34 refs., 11 figs., 5 tabs

  4. Dark Energy and Spacetime Symmetry

    Directory of Open Access Journals (Sweden)

    Irina Dymnikova

    2017-03-01

    Full Text Available The Petrov classification of stress-energy tensors provides a model-independent definition of a vacuum by the algebraic structure of its stress-energy tensor and implies the existence of vacua whose symmetry is reduced as compared with the maximally symmetric de Sitter vacuum associated with the Einstein cosmological term. This allows to describe a vacuum in general setting by dynamical vacuum dark fluid, presented by a variable cosmological term with the reduced symmetry which makes vacuum fluid essentially anisotropic and allows it to be evolving and clustering. The relevant solutions to the Einstein equations describe regular cosmological models with time-evolving and spatially inhomogeneous vacuum dark energy, and compact vacuum objects generically related to a dark energy: regular black holes, their remnants and self-gravitating vacuum solitons with de Sitter vacuum interiors—which can be responsible for observational effects typically related to a dark matter. The mass of objects with de Sitter interior is generically related to vacuum dark energy and to breaking of space-time symmetry. In the cosmological context spacetime symmetry provides a mechanism for relaxing cosmological constant to a needed non-zero value.

  5. Effects of Vision Restoration Training on Early Visual Cortex in Patients With Cerebral Blindness Investigated With Functional Magnetic Resonance Imaging

    NARCIS (Netherlands)

    Raemaekers, M.; Bergsma, D.P.; van Wezel, Richard Jack Anton; van der Wildt, G.J.; van den Berg, A.V.

    Cerebral blindness is a loss of vision as a result of postchiasmatic damage to the visual pathways. Parts of the lost visual field can be restored through training. However, the neuronal mechanisms through which training effects occur are still unclear. We therefore assessed training-induced changes

  6. Effects of Different Treatments of Pasture Restoration on Soil Trace Gas Emissions in the Cerrados of Central Brazil

    Science.gov (United States)

    Planted pastures ( mainly Brachiaria spp) are the most extensive land use in the cerrado (savannas of central Brazil) with an area of approximately 50 x 10(6) ha. The objective of the study was to assess the effects of pasture restoration on the N dynamics ( net N mineralization/...

  7. Mechanical behavior of a Y-TZP ceramic for monolithic restorations: effect of grinding and low-temperature aging

    NARCIS (Netherlands)

    Pereira, G.K.R.; Silvestri, T.; Camargo, R.; Rippe, M.P.; Amaral, M.; Kleverlaan, C.J.; Valandro, L.F.

    2016-01-01

    This study aimed to investigate the effects of grinding with diamond burs and low-temperature aging on the mechanical behavior (biaxial flexural strength and structural reliability), surface topography, and phase transformation of a Y-TZP ceramic for monolithic dental restorations. Disc-shaped

  8. Evaluating the effect of salinity on a simulated American crocodile (Crocodylus acutus) population with applications to conservation and Everglades restoration

    NARCIS (Netherlands)

    Richards, P.M.; Mooij, W.M.; DeAngelis, D.L.

    2004-01-01

    Everglades restoration will alter the hydrology of South Florida, affecting both water depth and salinity levels in the southern fringes of the Everglades, the habitat of the endangered American crocodile (Crocodylus acutus). A key question is what the effects of these hydrologic changes will be on

  9. The effect of human-caused visual impacts on restorative character of an arid wildland recreation setting

    Science.gov (United States)

    Thore Baird Christensen

    2009-01-01

    The purpose of this study is to examine the effects of visible visitor-caused impacts as characterized by user-created campsites on judgments about the perceived restorative character in natural areas. User-created campsites were inventoried using mapping-grade mobile Geographic Information Systems (GIS) technology and photography. Photography of user-created campsites...

  10. Effects of build direction on the mechanical properties of 3D-printed complete coverage interim dental restorations

    NARCIS (Netherlands)

    Alharbi, N.; Osman, R.; Wismeijer, D.

    2016-01-01

    Statement of problem. The application of 3-dimensional printing technology is emerging in dentistry and is being increasingly used to fabricate dental restorations. To date, scientific evidence is lacking regarding the effect of different factors on the mechanical properties of the printed

  11. Effect of core/veneer thickness ratio and veneer translucency on absolute and relative translucency of CAD-On restorations

    Directory of Open Access Journals (Sweden)

    Mennatallah Mohie el-Din Wahba, (BDS, MSc

    2017-06-01

    Conclusions: Only veneer translucency had significant effect over contrast ratio values, while on the other hand, absolute translucency values were significantly affected by the core/veneer thickness ratio, veneer translucency and interaction between them. It was clear that absolute translucency measurements showed higher translucency values for the restorations than contrast ratio measurements.

  12. The dipion mass spectrum in e+e- annihilation and tau decay: Isospin symmetry breaking effects from the (rho, omega, phi) mixing

    International Nuclear Information System (INIS)

    Benayoun, M.; David, P.; Del Buono, L.; O'Connell, H.B.; Leitner, O.

    2008-01-01

    A way to explain the puzzling difference between the pion form factor as measured in e + e - annihilations and in τ decays is discussed. We show that isospin symmetry breaking, beside the already identified effects, produces also a full mixing between the ρ 0 , ω and φ mesons which generates an isospin 0 component inside the ρ 0 meson. This effect, not accounted for in current treatments of the problem, seems able to account for the apparent mismatch between e + e - and τ data below the φ mass

  13. Genotoxic effects of silver amalgam and composite restorations: Micronuclei-Based cohort and case–control study in oral exfoliated cells

    Directory of Open Access Journals (Sweden)

    S Jeslin Mary

    2018-01-01

    Full Text Available Context: A huge number of people carry dental fillings which contain either mercury-based amalgam and/or the recently introduced methacrylate-based resins. It has been shown that both these materials are known to be leached into the oral cavity and induce genotoxic alterations in the buccal mucosal cells. Because of its low cost and ease of manipulation, dental amalgam is still widely used as a restorative material in developing countries. The health risks associated with the components of this restorative material has always been a matter of concern. The present study was designed to assess the frequency of micronuclei (MN in oral mucosal cells as it is a promising tool for studying the genotoxic effect of clastogenic agents on them. Aims: The aim of this study is to evaluate the genotoxic effects of silver amalgam and composite restorations by measuring the mean number of MN in oral exfoliated cells. Materials and Methods: The present study was a prospective cohort study which includes a study group consisting of 110 participants. The study sample was equally divided into 55 participants requiring only amalgam restoration and 55 participants requiring only composite restoration in any permanent molar teeth. The same participants before the restoration formed the control group. Smears were obtained from each patient before and 10 days after restoration and were stained with DNA-specific Feulgen stain. The number of cells containing MN out of 500 cells were counted and recorded. After the evaluation of the slides, the results were compiled and subjected to statistical analysis. Results: There was a statistically significant (P < 0.01 variation in the mean number of MN after the restoration in both amalgam (5.41 ± 1.25 and composite (2.83 ± 0.85 restorations when compared to before the restoration. However, the mean number of MN in composite restoration was significantly less when compared to amalgam restoration. There was also a statistically

  14. Hidden gauge symmetry

    International Nuclear Information System (INIS)

    O'Raifeartaigh, L.

    1979-01-01

    This review describes the principles of hidden gauge symmetry and of its application to the fundamental interactions. The emphasis is on the structure of the theory rather than on the technical details and, in order to emphasise the structure, gauge symmetry and hidden symmetry are first treated as independent phenomena before being combined into a single (hidden gauge symmetric) theory. The main application of the theory is to the weak and electromagnetic interactions of the elementary particles, and although models are used for comparison with experiment and for illustration, emphasis is placed on those features of the application which are model-independent. (author)

  15. Physics from symmetry

    CERN Document Server

    Schwichtenberg, Jakob

    2015-01-01

    This is a textbook that derives the fundamental theories of physics from symmetry.   It starts by introducing, in a completely self-contained way, all mathematical tools needed to use symmetry ideas in physics. Thereafter, these tools are put into action and by using symmetry constraints, the fundamental equations of Quantum Mechanics, Quantum Field Theory, Electromagnetism, and Classical Mechanics are derived. As a result, the reader is able to understand the basic assumptions behind, and the connections between the modern theories of physics. The book concludes with first applications of the previously derived equations.

  16. Dynamics of symmetry breaking in strongly coupled QED

    International Nuclear Information System (INIS)

    Bardeen, W.A.

    1988-10-01

    I review the dynamical structure of strong coupled QED in the quenched planar limit. The symmetry structure of this theory is examined with reference to the nature of both chiral and scale symmetry breaking. The renormalization structure of the strong coupled phase is analysed. The compatibility of spontaneous scale and chiral symmetry breaking is studied using effective lagrangian methods. 14 refs., 3 figs

  17. The effect of aging on the fracture toughness of esthetic restorative materials.

    Science.gov (United States)

    Bagheri, Rafat; Azar, Mohammad R; Tyas, Martin J; Burrow, Michael F

    2010-06-01

    To compare the fracture toughness (KIc) of tooth-colored restorative materials based on a four-point bending; to assess the effect of distilled water and a resin surface sealant (G-Coat Plus) on the resistance of the materials to fracture. Specimens were prepared from six materials: Quix Fil; Dyract (Dentsply), Freedom (SDI), Fuji VII (GC), Fuji IX (GC); Fuji II LC (GC). Fuji II LC and Fuji IX were tested both with and without applying G-Coat Plus (GC). The specimens were divided into the three groups which were conditioned in distilled water at 37 degrees C for 48 hours, 4 and 8 weeks. The specimens were loaded in a four-point bending test using a universal testing machine. The maximum load to specimen failure was recorded and the fracture toughness calculated. There were significant differences among most of the materials (P G-Coat Plus affected Fuji II LC positively while it had no effect on the Fuji IX.

  18. Effect of EDTA Conditioning on Microleakage of Four Adhesive Systems in Composite Restorations

    Directory of Open Access Journals (Sweden)

    F. Shafiei

    2008-12-01

    Full Text Available Objective: Evaluating the effect of dentin conditioning with EDTA on microleakage of composite resin restorations, using two etch and rinse and two self-etch adhesives.Materials and Methods: One hundred and sixty extracted molars received class V cavity preparations right under the CEJ and were randomly divided into eight groups of 20, usingfour different adhesive systems. These adhesives included Adper Scotchbond Multi-purpose (SBMP, Adper Single Bond (SB, Clearfil SE Bond (CSEB, and Adper Prompt L-Pop (PLP. In the SBMP and SB experimental groups, EDTA was applied instead of phosphoric acid. In the CSEB and PLP experimental groups, EDTA conditioning was added to the bonding process. After thermocycling, the amount of dye penetration was evaluated using stereomicroscope. The data were analyzed using the Kruskal-Wallis and Dunn tests.Results: Two etch and rinse adhesives (SBMP, SB showed a significantly lower micro-leakage than the two self-etch adhesives, CSEB and PLP, (P<0.05. No significant differ-ence was observed among the experimental groups. PLP and CSEB showed significantly less microleakage using EDTA conditioning (P<0.05. There was no significant difference for SBMP and SB when applying either phosphoric acid or EDTA.Conclusion: In the cases of SBMP and SB, EDTA conditioning is as effective as phos-phoric acid in preventing microleakage. In cases of CSEB and PLP, EDTA conditioning can significantly improve the sealing ability.

  19. Effects of Near Soil Surface Characteristics on the Soil Detachment Process in a Chronological Series of Vegetation Restoration

    Science.gov (United States)

    Wang, Bing

    2017-04-01

    The effects of near soil surface characteristics on the soil detachment process might be different at different stages of vegetation restoration. This study was performed to investigate the effects of the near soil surface factors of plant litter, biological soil crusts (BSCs), dead roots and live roots on the soil detachment process by overland flow at different stages of restoration. Soil samples (1 m long, 0.1 m wide, and 0.05 m high) under four treatment conditions were collected from 1-yr-old and 24-yr-old natural grasslands and subjected to flow scouring under five different shear stresses ranging from 5.3 to 14.6 Pa. The results indicated that the effects of near soil surface characteristics on soil detachment were substantial during the process of vegetation restoration. The total reduction in the soil detachment capacity of the 1-yr-old grassland was 98.1%, and of this total, 7.9%, 30.0% and 60.2% was attributed to the litter, BSCs and plant roots, respectively. In the 24-yr-old grassland, the soil detachment capacity decreased by 99.0%, of which 13.2%, 23.5% and 62.3% was caused by the litter, BSCs and plant roots, respectively. Combined with the previously published data of a 7-yr-old grassland, the influence of plant litter on soil detachment was demonstrated to increase with restoration time, but soil detachment was also affected by the litter type and composition. The role of BSCs was greater than that of plant litter in reducing soil detachment during the early stages of vegetation recovery. However, its contribution weakened with time since restoration. The influence of plant roots accounted for at least half or up to two-thirds of the total near soil surface factors, of which more than 72.6% was attributed to the physical binding effects of the roots. The chemical bonding effect of the roots increased with time since restoration and was greater than the effect of the litter on soil detachment in the late stages of vegetation restoration. The

  20. Mirror Lake genetic stock - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  1. Mirror Lake salmon prey and diets - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  2. Mirror Lake Fish catch composition - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  3. Mirror Lake salmon growth rate - Lower Columbia River Restoration Action Effectiveness Monitoring

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 1) The purpose of this project is to measure changes in juvenile salmon habitat occurrence and health following restoration activities at the Mirror Lake Complex and...

  4. Passive restoration is often quite effective: response to Zahawi et al. (2014)

    Czech Academy of Sciences Publication Activity Database

    Prach, Karel; del Moral, R.

    2015-01-01

    Roč. 23, č. 4 (2015), s. 344-346 ISSN 1061-2971 Institutional support: RVO:67985939 Keywords : restoration * succession * disturbance Subject RIV: EH - Ecology, Behaviour Impact factor: 1.891, year: 2015

  5. A comparative analysis of restoration measures and their effects on hydromorphology and benthic invertebrates in 26 central and southern European rivers.

    NARCIS (Netherlands)

    Jähnig, S.C.; Brabec, K.; Buffagni, A.; Erba, S.; Lorenz, A.; Ofenböck, T.; Verdonschot, P.F.M.; Hering, D.

    2010-01-01

    1. Hydromorphological river restoration usually leads to habitat diversification, but the effects on benthic invertebrates, which are frequently used to assess river ecological status, are minor. We compared the effects of river restoration on morphology and benthic invertebrates by investigating 26

  6. Generalized symmetry algebras

    International Nuclear Information System (INIS)

    Dragon, N.

    1979-01-01

    The possible use of trilinear algebras as symmetry algebras for para-Fermi fields is investigated. The shortcomings of the examples are argued to be a general feature of such generalized algebras. (author)

  7. Segmentation Using Symmetry Deviation

    DEFF Research Database (Denmark)

    Hollensen, Christian; Højgaard, L.; Specht, L.

    2011-01-01

    of the CT-scans into a single atlas. Afterwards the standard deviation of anatomical symmetry for the 20 normal patients was evaluated using non-rigid registration and registered onto the atlas to create an atlas for normal anatomical symmetry deviation. The same non-rigid registration was used on the 10...... hypopharyngeal cancer patients to find anatomical symmetry and evaluate it against the standard deviation of the normal patients to locate pathologic volumes. Combining the information with an absolute PET threshold of 3 Standard uptake value (SUV) a volume was automatically delineated. The overlap of automated....... The standard deviation of the anatomical symmetry, seen in figure for one patient along CT and PET, was extracted for normal patients and compared with the deviation from cancer patients giving a new way of determining cancer pathology location. Using the novel method an overlap concordance index...

  8. Statistical symmetries in physics

    International Nuclear Information System (INIS)

    Green, H.S.; Adelaide Univ., SA

    1994-01-01

    Every law of physics is invariant under some group of transformations and is therefore the expression of some type of symmetry. Symmetries are classified as geometrical, dynamical or statistical. At the most fundamental level, statistical symmetries are expressed in the field theories of the elementary particles. This paper traces some of the developments from the discovery of Bose statistics, one of the two fundamental symmetries of physics. A series of generalizations of Bose statistics is described. A supersymmetric generalization accommodates fermions as well as bosons, and further generalizations, including parastatistics, modular statistics and graded statistics, accommodate particles with properties such as 'colour'. A factorization of elements of ggl(n b ,n f ) can be used to define truncated boson operators. A general construction is given for q-deformed boson operators, and explicit constructions of the same type are given for various 'deformed' algebras. A summary is given of some of the applications and potential applications. 39 refs., 2 figs

  9. Wigner's Symmetry Representation Theorem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 10. Wigner's Symmetry Representation Theorem: At the Heart of Quantum Field Theory! Aritra Kr Mukhopadhyay. General Article Volume 19 Issue 10 October 2014 pp 900-916 ...

  10. Joint analysis of stressors and ecosystem services to enhance restoration effectiveness.

    Science.gov (United States)

    Allan, J David; McIntyre, Peter B; Smith, Sigrid D P; Halpern, Benjamin S; Boyer, Gregory L; Buchsbaum, Andy; Burton, G A; Campbell, Linda M; Chadderton, W Lindsay; Ciborowski, Jan J H; Doran, Patrick J; Eder, Tim; Infante, Dana M; Johnson, Lucinda B; Joseph, Christine A; Marino, Adrienne L; Prusevich, Alexander; Read, Jennifer G; Rose, Joan B; Rutherford, Edward S; Sowa, Scott P; Steinman, Alan D

    2013-01-02

    With increasing pressure placed on natural systems by growing human populations, both scientists and resource managers need a better understanding of the relationships between cumulative stress from human activities and valued ecosystem services. Societies often seek to mitigate threats to these services through large-scale, costly restoration projects, such as the over one billion dollar Great Lakes Restoration Initiative currently underway. To help inform these efforts, we merged high-resolution spatial analyses of environmental stressors with mapping of ecosystem services for all five Great Lakes. Cumulative ecosystem stress is highest in near-shore habitats, but also extends offshore in Lakes Erie, Ontario, and Michigan. Variation in cumulative stress is driven largely by spatial concordance among multiple stressors, indicating the importance of considering all stressors when planning restoration activities. In addition, highly stressed areas reflect numerous different combinations of stressors rather than a single suite of problems, suggesting that a detailed understanding of the stressors needing alleviation could improve restoration planning. We also find that many important areas for fisheries and recreation are subject to high stress, indicating that ecosystem degradation could be threatening key services. Current restoration efforts have targeted high-stress sites almost exclusively, but generally without knowledge of the full range of stressors affecting these locations or differences among sites in service provisioning. Our results demonstrate that joint spatial analysis of stressors and ecosystem services can provide a critical foundation for maximizing social and ecological benefits from restoration investments.

  11. Flavour from accidental symmetries

    International Nuclear Information System (INIS)

    Ferretti, Luca; King, Stephen F.; Romanino, Andrea

    2006-01-01

    We consider a new approach to fermion masses and mixings in which no special 'horizontal' dynamics is invoked to account for the hierarchical pattern of charged fermion masses and for the peculiar features of neutrino masses. The hierarchy follows from the vertical, family-independent structure of the model, in particular from the breaking pattern of the Pati-Salam group. The lightness of the first two fermion families can be related to two family symmetries emerging in this context as accidental symmetries

  12. Crocin Restores Hypotensive Effect of Subchronic Administration of Diazinon in Rats

    Directory of Open Access Journals (Sweden)

    Marjan Razavi

    2013-01-01

    Full Text Available Objective(s: In this study, the effects of crocin against subchronic toxicity of diazinon (DZN on systolic blood pressure (SBP and heart rate (HR were evaluated in rats. Materials and Methods: Rats were equally divided into 7 groups; control (corn oil, DZN (15 mg/kg, crocin (each group received 12.5, 25 or 50 mg/kg crocin plus DZN, vitamin E (200 IU/kg plus DZN and crocin (50 mg/kg treated groups.  Rats were given DZN via gavage once a day for 4 weeks. Vitamin E (three times per week and crocin (once a day were intraperitoneally injected to rats for 4 weeks. Plasma cholinesterase activity (Elman method, malondealdehyde (MDA levels in the aortic tissue (Thiobarbituric acid reactive substances or TBARS method; SBP and HR (tail cuff method were evaluated at the end of 4th week. Results: A significant decrease in cholinesterase activity was observed in DZN group (P< 0.001. Crocin did not show any effects on cholinesterase activity. DZN increased MDA levels in aortic tissue (P< 0.001 in comparison with control group. Crocin and vitamin E plus DZN decreased MDA elevation induced by DZN in aortic tissue. DZN significantly reduced SBP (P< 0.01 and increased HR (P< 0.001 in comparison with control. Concurrent administration of crocin and DZN, improved the reduction of SBP and the elevation of HR induced by DZN in rat. Crocin alone did not have any effect on SBP and HR. Conclusion: This study showed that concurrent administration of crocin and DZN could restore the effects of subchronic DZN administration on SBP and HR in rats.

  13. Restoring effects of oxytocin on the attentional preference for faces in autism.

    Science.gov (United States)

    Kanat, M; Spenthof, I; Riedel, A; van Elst, L T; Heinrichs, M; Domes, G

    2017-04-18

    Reduced attentional preference for faces and symptoms of social anxiety are common in autism spectrum disorders (ASDs). The neuropeptide oxytocin triggers anxiolytic functions and enhances eye gaze, facial emotion recognition and neural correlates of face processing in ASD. Here we investigated whether a single dose of oxytocin increases attention to faces in ASD. As a secondary question, we explored the influence of social anxiety on these effects. We tested for oxytocin's effects on attention to neutral faces as compared to houses in a sample of 29 autistic individuals and 30 control participants using a dot-probe paradigm with two different presentation times (100 or 500 ms). A single dose of 24 IU oxytocin was administered in a randomized, double-blind placebo-controlled, cross-over design. Under placebo, ASD individuals paid less attention to faces presented for 500 ms than did controls. Oxytocin administration increased the allocation of attention toward faces in ASD to a level observed in controls. Secondary analyses revealed that these oxytocin effects primarily occurred in ASD individuals with high levels of social anxiety who were characterized by attentional avoidance of faces under placebo. Our results confirm a positive influence of intranasal oxytocin on social attention processes in ASD. Further, they suggest that oxytocin may in particular restore the attentional preference for facial information in ASD individuals with high social anxiety. We conclude that oxytocin's anxiolytic properties may partially account for its positive effects on socio-cognitive functioning in ASD, such as enhanced eye gaze and facial emotion recognition.

  14. Effects of soil and topographic factors on vegetation restoration in opencast coal mine dumps located in a loess area

    Science.gov (United States)

    Wang, Jinman; Wang, Hongdan; Cao, Yingui; Bai, Zhongke; Qin, Qian

    2016-02-01

    Vegetation plays an important role in improving and restoring fragile ecological environments. In the Antaibao opencast coal mine, located in a loess area, the eco-environment has been substantially disturbed by mining activities, and the relationship between the vegetation and environmental factors is not very clear. Therefore, it is crucial to understand the effects of soil and topographic factors on vegetation restoration to improve the fragile ecosystems of damaged land. An investigation of the soil, topography and vegetation in 50 reclamation sample plots in Shanxi Pingshuo Antaibao opencast coal mine dumps was performed. Statistical analyses in this study included one-way ANOVA and significance testing using SPSS 20.0, and multivariate techniques of detrended correspondence analysis (DCA) and redundancy analysis (RDA) using CANOCO 4.5. The RDA revealed the environmental factors that affected vegetation restoration. Various vegetation and soil variables were significantly correlated. The available K and rock content were good explanatory variables, and they were positively correlated with tree volume. The effects of the soil factors on vegetation restoration were higher than those of the topographic factors.

  15. Effects of soil and topographic factors on vegetation restoration in opencast coal mine dumps located in a loess area

    Science.gov (United States)

    Wang, Jinman; Wang, Hongdan; Cao, Yingui; Bai, Zhongke; Qin, Qian

    2016-01-01

    Vegetation plays an important role in improving and restoring fragile ecological environments. In the Antaibao opencast coal mine, located in a loess area, the eco-environment has been substantially disturbed by mining activities, and the relationship between the vegetation and environmental factors is not very clear. Therefore, it is crucial to understand the effects of soil and topographic factors on vegetation restoration to improve the fragile ecosystems of damaged land. An investigation of the soil, topography and vegetation in 50 reclamation sample plots in Shanxi Pingshuo Antaibao opencast coal mine dumps was performed. Statistical analyses in this study included one-way ANOVA and significance testing using SPSS 20.0, and multivariate techniques of detrended correspondence analysis (DCA) and redundancy analysis (RDA) using CANOCO 4.5. The RDA revealed the environmental factors that affected vegetation restoration. Various vegetation and soil variables were significantly correlated. The available K and rock content were good explanatory variables, and they were positively correlated with tree volume. The effects of the soil factors on vegetation restoration were higher than those of the topographic factors. PMID:26916152

  16. Effectiveness of a lifestyle exercise program for older people receiving a restorative home care service: a pragmatic randomized controlled trial.

    Science.gov (United States)

    Burton, Elissa; Lewin, Gill; Clemson, Lindy; Boldy, Duncan

    2013-01-01

    Restorative home care services are short-term and aimed at maximizing a person's ability to live independently. They are multidimensional and often include an exercise program to improve strength, mobility, and balance. The aim of this study was to determine whether a lifestyle exercise program would be undertaken more often and result in greater functional gains than the current structured exercise program delivered as part of a restorative home care service for older adults. A pragmatic randomized controlled trial was conducted in an organization with an established restorative home care service. Individuals who were to have an exercise program as part of their service were randomized to receive either a lifestyle and functional exercise program called LiFE (as this was a new program, the intervention) or the structured exercise program currently being used in the service (control). Exercise data collected by the individuals throughout and pre and post intervention testing was used to measure balance, strength, mobility, falls efficacy, vitality, function, and disability. There was no difference between the groups in the amounts of exercise undertaken during the 8-week intervention period. Outcome measurement indicated that the LiFE program was as effective, and on 40% of the measures, more effective, than the structured exercise program. Organizations delivering restorative home care services that include an exercise component should consider whether LiFE rather than the exercise program they are currently using could help their clients achieve better outcomes.

  17. Dihedral flavor symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Blum, Alexander Simon

    2009-06-10

    This thesis deals with the possibility of describing the flavor sector of the Standard Model of Particle Physics (with neutrino masses), that is the fermion masses and mixing matrices, with a discrete, non-abelian flavor symmetry. In particular, mass independent textures are considered, where one or several of the mixing angles are determined by group theory alone and are independent of the fermion masses. To this end a systematic analysis of a large class of discrete symmetries, the dihedral groups, is analyzed. Mass independent textures originating from such symmetries are described and it is shown that such structures arise naturally from the minimization of scalar potentials, where the scalars are gauge singlet flavons transforming non-trivially only under the flavor group. Two models are constructed from this input, one describing leptons, based on the group D{sub 4}, the other describing quarks and employing the symmetry D{sub 14}. In the latter model it is the quark mixing matrix element V{sub ud} - basically the Cabibbo angle - which is at leading order predicted from group theory. Finally, discrete flavor groups are discussed as subgroups of a continuous gauge symmetry and it is shown that this implies that the original gauge symmetry is broken by fairly large representations. (orig.)

  18. Dihedral flavor symmetries

    International Nuclear Information System (INIS)

    Blum, Alexander Simon

    2009-01-01

    This thesis deals with the possibility of describing the flavor sector of the Standard Model of Particle Physics (with neutrino masses), that is the fermion masses and mixing matrices, with a discrete, non-abelian flavor symmetry. In particular, mass independent textures are considered, where one or several of the mixing angles are determined by group theory alone and are independent of the fermion masses. To this end a systematic analysis of a large class of discrete symmetries, the dihedral groups, is analyzed. Mass independent textures originating from such symmetries are described and it is shown that such structures arise naturally from the minimization of scalar potentials, where the scalars are gauge singlet flavons transforming non-trivially only under the flavor group. Two models are constructed from this input, one describing leptons, based on the group D 4 , the other describing quarks and employing the symmetry D 14 . In the latter model it is the quark mixing matrix element V ud - basically the Cabibbo angle - which is at leading order predicted from group theory. Finally, discrete flavor groups are discussed as subgroups of a continuous gauge symmetry and it is shown that this implies that the original gauge symmetry is broken by fairly large representations. (orig.)

  19. Effective actions and topological strings. Off-shell mirror symmetry and mock modularity of multiple M5-branes

    International Nuclear Information System (INIS)

    Hecht, Michael

    2011-01-01

    This thesis addresses two different topics within the field of string theory. In the first part it is shown how Hodge-theoretic methods in conjunction with open string mirror symmetry can be used to compute non-perturbative effective superpotential couplings for type II/F-theory compactifications with D-branes and fluxes on compact Calabi-Yau manifolds. This is achieved by studying the at structure of operators which derives from the open/closed Β-model geometry. We analyze the variation of mixed Hodge structure of the relative cohomology induced by a family of divisors, which is wrapped by a D7-brane. This leads to a Picard-Fuchs system of differential operators, which can be used to compute the moduli dependence of the superpotential couplings as well as the mirror maps at various points in the open/closed deformation space. These techniques are used to obtain predictions for genuine A-model Ooguri-Vafa invariants of special Lagrangian submanifolds in compact Calabi-Yau geometries and real enumerative invariants of on-shell domain wall tensions. By an open/closed duality the system of differential equations can also be obtained from a gauged linear σ-model, which describes a non-compact Calabi-Yau four-fold compactification without branes. This is used in the examples of multi-parameter models to study the various phases of the combined open/closed deformation space. It is furthermore shown how the brane geometry can be related to a F-theory compactification on a compact Calabi-Yau four-fold, where the Hodge-theoretic techniques can be used to compute the G-flux induced Gukov-Vafa-Witten potential. The dual F-theory picture also allows to conjecture the form of the Kaehler potential on the full open/closed deformation space. In the second part we analyze the background dependence of theories which derive from multiple wrapped M5-branes. Using the Kontsevich-Soibelman wall-crossing formula and the theory of mock modular forms we derive a holomorphic anomaly

  20. Effective actions and topological strings. Off-shell mirror symmetry and mock modularity of multiple M5-branes

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, Michael

    2011-10-20

    This thesis addresses two different topics within the field of string theory. In the first part it is shown how Hodge-theoretic methods in conjunction with open string mirror symmetry can be used to compute non-perturbative effective superpotential couplings for type II/F-theory compactifications with D-branes and fluxes on compact Calabi-Yau manifolds. This is achieved by studying the at structure of operators which derives from the open/closed {beta}-model geometry. We analyze the variation of mixed Hodge structure of the relative cohomology induced by a family of divisors, which is wrapped by a D7-brane. This leads to a Picard-Fuchs system of differential operators, which can be used to compute the moduli dependence of the superpotential couplings as well as the mirror maps at various points in the open/closed deformation space. These techniques are used to obtain predictions for genuine A-model Ooguri-Vafa invariants of special Lagrangian submanifolds in compact Calabi-Yau geometries and real enumerative invariants of on-shell domain wall tensions. By an open/closed duality the system of differential equations can also be obtained from a gauged linear {sigma}-model, which describes a non-compact Calabi-Yau four-fold compactification without branes. This is used in the examples of multi-parameter models to study the various phases of the combined open/closed deformation space. It is furthermore shown how the brane geometry can be related to a F-theory compactification on a compact Calabi-Yau four-fold, where the Hodge-theoretic techniques can be used to compute the G-flux induced Gukov-Vafa-Witten potential. The dual F-theory picture also allows to conjecture the form of the Kaehler potential on the full open/closed deformation space. In the second part we analyze the background dependence of theories which derive from multiple wrapped M5-branes. Using the Kontsevich-Soibelman wall-crossing formula and the theory of mock modular forms we derive a holomorphic

  1. Effect of Accelerated Aging on Color Change of Direct and Indirect Fiber-Reinforced Composite Restorations

    Directory of Open Access Journals (Sweden)

    Masomeh Hasani Tabatabaei

    2016-10-01

    Full Text Available Objectives: The aim of this study was to assess the effect of artificial accelerated aging (AAA on color change of direct and indirect fiber-reinforced composite (FRC restorations.Materials and Methods: Direct (Z250 and indirect (Gradia composite resins were reinforced with glass (GF and polyethylene fibers (PF based on the manufacturers’ instructions. Forty samples were fabricated and divided into eight groups (n=5. Four groups served as experimental groups and the remaining four served as controls. Color change (∆E and color parameters (∆L*, ∆a*, ∆b* were read at baseline and after AAA based on the CIELAB system. Three-way ANOVA and Tukey’s test were used for statistical analysis.Results: Significant differences were found in ΔE, ΔL*, Δa* and Δb* among the groups after AAA (P<0.05. Most of the studied samples demonstrated an increase in lightness and a red-yellow shift after AAA.Conclusions: The obtained ∆E values were unacceptable after AAA (∆E≥ 3.3. All indirect samples showed a green-blue shift with a reduction in lightness except for Gradia/PF+ NuliteF.Keywords: Aging; Composite Resins; Color

  2. Model Studies on the Effectiveness of MBBR Reactors for the Restoration of Small Water Reservoirs

    Science.gov (United States)

    Nowak, Agata; Mazur, Robert; Panek, Ewa; Chmist, Joanna

    2018-02-01

    The authors present the Moving Bed Biofilm Reactor (MBBR) model with a quasi-continuous flow for small water reservoir restoration, characterized by high concentrations of organic pollutants. To determine the efficiency of wastewater treatment the laboratory analysis of physic-chemical parameters were conducted for the model on a semi-technical scale of 1:3. Wastewater treatment process was carried out in 24 h for 1 m3 for raw sewage. The startup period was 2 weeks for all biofilters (biological beds). Approximately 50% reduction in COD and BOD5 was obtained on average for the studied bioreactors. Significant improvements were achieved in theclarity of the treated wastewater, with the reduction of suspension by 60%. The oxygen profile has improved significantly in 7 to 9 hours of the process, and a diametric reduction in the oxidative reduction potential was recorded. A preliminary model of biological treatment effectiveness was determined based on the conducted studies. In final stages, the operation mode was set in real conditions of polluted water reservoirs.

  3. Effect of preparation convergence on retention of multiple unit restorations - An in vitrostudy

    Directory of Open Access Journals (Sweden)

    Dileep Nag Vinnakota

    2015-01-01

    Full Text Available Background and Aim: Convergence angle (CA is one of the major determinant factors in the retention of single as well as multiple units. Hence, the aim of the present study was to determine the effect of preparation convergence on the retention of multiple unit restorations. Materials and Methods: Nickel-chromium alloy single crowns as well as three, six and nine multiple unit fixed partial dentures (FPDs were casted for standardized milled dies that simulate canine, premolar and molar teeth machined with two different degrees of convergence, 12 (n = 55 and 20 (n = 55. The dies were threaded on rectangular metal platforms with the help of retainer shaft in the proper position to model either single or multiple preparations. The casted crowns and FPDs were cemented and retention tested by securing the units in an Instron universal testing machine. The tabulated values were analyzed statistically using Mann-Whitney test. Results: Single and multiple units with 12° CA needed greater force to dislodge compared to 20°, but this difference was not statistically significant for single units of premolar (P > 0.05. Irrespective of the angle, there was a simultaneous statistically significant increase in retention as the number of units increased in FPDs, except for the difference between 3 and 6 units in 20° group (P > 0.05. Conclusion: This study highlights the importance of emphasizing on CA, during canine and molar preparation for single units as well as preparation of canines for 6 units FPDs.

  4. Restorative effect of peritoneal macrophages on delayed hypersensitivity following ionizing radiation

    International Nuclear Information System (INIS)

    Volkman, A.; Collins, F.M.

    1971-01-01

    Sublethal whole-body irradiation in the guinea pig had little demonstrable effect on the development of delayed hypersensitivity but caused a profound, though transient depression of dermal reactivity in previously sensitized animals. Macrophage-rich peritoneal cell suspensions from non-sensitive donors when injected intradermally with eliciting antigen, resulted in the restoration of a significant degree of reactivity following irradiation. Inocula of lymphocytes, on the other hand, failed to yield similar results. These findings, when taken with the persistence of low levels of reactivity following irradiation and the ability to transfer reactivity with peritoneal exudate cells from animals so treated, warrant the conclusion that the presence of macrophages is necessary for the expression of cutaneous delayed hypersensitivity. The spontaneously renewed activity which follows the depressed phase is thus more of a reflection of the recovery of macrophage precursors from radiation injury, rather than the emergence of a new population of sensitized cells. The results, in addition, substantiate the belief that the expression of delayed hypersensitivity requires at least two cell populations, only one of which carries the property of specificity at the outset

  5. Noncompact symmetries in string theory

    International Nuclear Information System (INIS)

    Maharana, J.; Schwarz, J.H.

    1993-01-01

    Noncompact groups, similar to those that appeared in various supergravity theories in the 1970's have been turning up in recent studies of string theory. First it was discovered that moduli spaces of toroidal compactification are given by noncompact groups modded out by their maximal compact subgroups and discrete duality groups. Then it was found that many other moduli spaces have analogous descriptions. More recently, noncompact group symmetries have turned up in effective actions used to study string cosmology and other classical configurations. This paper explores these noncompact groups in the case of toroidal compactification both from the viewpoint of low-energy effective field theory, using the method of dimensional reduction, and from the viewpoint of the string theory world-sheet. The conclusion is that all these symmetries are intimately related. In particular, we find that Chern-Simons terms in the three-form field strength H μνρ play a crucial role. (orig.)

  6. Effects of Broken Symmetry in Tokamaks: Global Braking of Toroidal Rotation and Self-consistent Determination of Neoclassical Magnetic Islands Velocity

    International Nuclear Information System (INIS)

    Lazzaro, Enzo

    2009-01-01

    Established results of neoclassical kinetic theory are used in a fluid model to show that in low collisionality regimes (ν and 1/ν) the propagation velocity of Neoclassical Tearing Modes (NTM) magnetic islands of sufficient width is determined self-consistently by the Neoclassical Toroidal Viscosity (NTV) appearing because of broken symmetry. The NTV effect on bulk plasma rotation, may also explain recent observations on momentum transport. At the same time this affects the role of the neoclassical ion polarization current on neoclassical tearing modes (NTM) stability.

  7. The effect of public social context on self-control: depletion for neuroticism and restoration for impression management.

    Science.gov (United States)

    Uziel, Liad; Baumeister, Roy F

    2012-03-01

    The present study explores the role of personality in moderating the effect of public social context on self-control. The authors predicted that in public settings neuroticism would be associated with ego-depletion effects and individual differences in impression management (IM) would be associated with restoration effects. Three experiments supported the hypothesis. In Study 1 neuroticism was associated with impaired self-control and IM was associated with enhanced self-control following an initial phase of working on a simple task in public (vs. in private). Study 2 replicated and extended these results to other domains of self-control. Study 3 explored whether public social context can cancel out early depletion effects. In this study, depleted participants engaged in a task that required self-control either alone or in public. As expected, the public settings were associated with restored self-control resources mostly among high IM individuals. Implications for self-control, neuroticism, and IM are discussed.

  8. Effect of broken axial symmetry on the electric dipole strength and the collective enhancement of level densities in heavy nuclei

    Science.gov (United States)

    Grosse, E.; Junghans, A. R.; Wilson, J. N.

    2017-11-01

    The basic parameters for calculations of radiative neutron capture, photon strength functions and nuclear level densities near the neutron separation energy are determined based on experimental data without an ad hoc assumption about axial symmetry—at variance to previous analysis. Surprisingly few global fit parameters are needed in addition to information on nuclear deformation, taken from Hartree Fock Bogolyubov calculations with the Gogny force, and the generator coordinator method assures properly defined angular momentum. For a large number of nuclei the GDR shapes and the photon strength are described by the sum of three Lorentzians, extrapolated to low energies and normalised in accordance to the dipole sum rule. Level densities are influenced strongly by the significant collective enhancement based on the breaking of shape symmetry. The replacement of axial symmetry by the less stringent requirement of invariance against rotation by 180° leads to a novel prediction for radiative neutron capture. It compares well to recent compilations of average radiative widths and Maxwellian average cross sections for neutron capture by even target nuclei. An extension to higher spin promises a reliable prediction for various compound nuclear reactions also outside the valley of stability. Such predictions are of high importance for future nuclear energy systems and waste transmutation as well as for the understanding of the cosmic synthesis of heavy elements.

  9. A physical framework for evaluating net effects of wet meadow restoration on late summer streamflow

    Science.gov (United States)

    Grant, G.; Nash, C.; Selker, J. S.; Lewis, S.; Noël, P.

    2017-12-01

    Restoration of degraded wet meadows that develop on upland valley floors is intended to achieve a range of ecological benefits. A widely cited benefit is the potential for meadow restoration to augment late-season streamflow; however, there has been little field data demonstrating increased summer flows following restoration. Instead, the hydrologic consequences of restoration have typically been explored using coupled groundwater and surface water flow models at instrumented sites. The expected magnitude and direction of change provided by models has, however, been inconclusive. Here, we assess the streamflow benefit that can be obtained by wet meadow restoration using a parsimonious, physically-based approach. We use a one-dimensional linearized Boussinesq equation with a superimposed solution for changes in storage due to groundwater upwelling and and explicitly calculate evapotranspiration using the White Method. The model accurately predicts water table elevations from field data in the Middle Fork John Day watershed in Oregon, USA. The full solution shows that while raising channel beds can increase total water storage via increases in water table elevation in upland valley bottoms, the contributions of both lateral and longitudinal drainage from restored floodplains to late summer streamflow are undetectably small, while losses in streamflow due to greater transpiration, lower hydraulic gradients, and less drainable pore volume are substantial. Although late-summer streamflow increases should not be expected as a direct result of wet meadow restoration, these approaches offer benefits for improving the quality and health of riparian and meadow vegetation that would warrant considering such measures, even at the cost of increased water demand and reduced streamflow.

  10. The Effect of Composite Thickness on the Stress Distribution Pattern of Restored Premolar Teeth with Cusp Reduction.

    Science.gov (United States)

    Panahandeh, Narges; Torabzadeh, Hassan; Ziaee, Nargess; Mahdian, Mina; Tootiaee, Bahman; Ghasemi, Amir

    2017-07-01

    Different thicknesses of restorative material can alter the stress distribution pattern in remaining tooth structure. The assumption is that a thicker composite restoration will induce a higher fracture resistance. Therefore, the present study evaluated the effect of composite thickness on stress distribution in a restored premolar with cusp reduction. A 3D solid model of a maxillary second premolar was prepared and meshed. MOD cavities were designed with different cusp reduction thicknesses (0, 0.5, 1, 1.5, 2.5 mm). Cavities were restored with Valux Plus composite. They were loaded with 200 N force on the occlusal surface in the direction of the long axis. Von Mises stresses were evaluated with Abaqus software. Stress increased from occlusal to gingival and was maximum in the cervical region. The stressed area in the palatal cusp was more than that of the buccal cusp. Increasing the thickness of composite altered the shear stress to compressive stress in the occlusal area of the teeth. The model with 2.5 mm cusp reduction exhibited the most even stress distribution. © 2015 by the American College of Prosthodontists.

  11. Confinement/deconfinement transition from symmetry breaking in gauge/gravity duality

    Energy Technology Data Exchange (ETDEWEB)

    Čubrović, Mihailo [Institute for Theoretical Physics, University of Cologne,Zülpicher Strasse 77, D-50937, Cologne (Germany)

    2016-10-19

    We study the confinement/deconfinement transition in a strongly coupled system triggered by an independent symmetry-breaking quantum phase transition in gauge/gravity duality. The gravity dual is an Einstein-scalar-dilaton system with AdS near-boundary behavior and soft wall interior at zero scalar condensate. We study the cases of neutral and charged condensate separately. In the former case the condensation breaks the discrete ℤ{sub 2} symmetry while a charged condensate breaks the continuous U(1) symmetry. After the condensation of the order parameter, the non-zero vacuum expectation value of the scalar couples to the dilaton, changing the soft wall geometry into a non-confining and anisotropically scale-invariant infrared metric. In other words, the formation of long-range order is immediately followed by the deconfinement transition and the two critical points coincide. The confined phase has a scale — the confinement scale (energy gap) which vanishes in the deconfined case. Therefore, the breaking of the symmetry of the scalar (ℤ{sub 2} or U(1)) in turn restores the scaling symmetry in the system and neither phase has a higher overall symmetry than the other. When the scalar is charged the phase transition is continuous which goes against the Ginzburg-Landau theory where such transitions generically only occur discontinuously. This phenomenon has some commonalities with the scenario of deconfined criticality. The mechanism we have found has applications mainly in effective field theories such as quantum magnetic systems. We briefly discuss these applications and the relation to real-world systems.

  12. Ecological restoration and effect investigation of a river wetland in a semi-arid region, China

    Science.gov (United States)

    Xu, S.; Jiang, X.; Liu, Y.; Fu, Y.; Zhao, Q.

    2015-05-01

    River wetlands are heavily impacted by human intervention. The degradation and loss of river wetlands has made the restoration of river ecosystems a top priority. How to rehabilitate rivers and their services has been a research focus. The main goal of it is to restore the river wetland ecosystems with ecological methods. The Gudong River was selected as a study site in Chaoyang city in this study. Based on the analysis of interference factors in the river wetland degradation, a set of restoration techniques were proposed and designed for regional water level control, including submerged dikes, ecological embankments, revegetation and dredging. The restoration engineering has produced good results in water quality, eco-environment, and landscape. Monthly reports of the Daling River show that the water quality of Gudong River was better than Grade III in April 2013 compared with Grade V in May 2012. The economic benefit after restoration construction is 1.71 million RMB per year, about 1.89 times that before. The ratio of economic value, social value and eco-environmental value is 1:4:23.

  13. Gravitation and Gauge Symmetries

    CERN Document Server

    Stewart, J

    2002-01-01

    The purpose of this book (I quote verbatim from the back cover) is to 'shed light upon the intrinsic structure of gravity and the principle of gauge invariance, which may lead to a consistent unified field theory', a very laudable aim. The content divides fairly clearly into four sections (and origins). After a brief introduction, chapters 2-6 review the 'Structure of gravity as a theory based on spacetime gauge symmetries'. This is fairly straightforward material, apparently based on a one-semester graduate course taught at the University of Belgrade for about two decades, and, by implication, this is a reasonably accurate description of its level and assumed knowledge. There follow two chapters of new material entitled 'Gravity in flat spacetime' and 'Nonlinear effects in gravity'. The final three chapters, entitled 'Supersymmetry and supergravity', 'Kaluza-Klein theory' and 'String theory' have been used for the basis of a one-semester graduate course on the unification of fundamental interactions. The boo...

  14. Quark diquark symmetry breaking

    International Nuclear Information System (INIS)

    Souza, M.M. de

    1980-01-01

    Assuming the baryons are made of quark-diquark pairs, the wave functions for the 126 allowed ground states are written. The quark creation and annihilations operators are generalized to describe the quark-diquark structure in terms of a parameter σ. Assuming that all quark-quark interactions are mediated by gluons transforming like an octet of vector mesons, the effective Hamiltonian and the baryon masses as constraint equations for the elements of the mass matrix is written. The symmetry is the SU(6) sub(quark)x SU(21) sub(diquark) broken by quark-quark interactions respectively invariant under U(6), U(2) sub(spin), U(3) and also interactions transforming like the eighth and the third components of SU(3). In the limit of no quark-diquark structure (σ = 0), the ground state masses is titted to within 1% of the experimental data, except for the Δ(1232), where the error is almost 2%. Expanding the decuplet mass equations in terms of σ and keeping terms only up to the second order, this error is reduced to 67%. (Author) [pt

  15. Gauging policy-driven large-scale vegetation restoration programmes under a changing environment: Their effectiveness and socio-economic relationships.

    Science.gov (United States)

    Li, Ting; Lü, Yihe; Fu, Bojie; Comber, Alexis J; Harris, Paul; Wu, Lianhai

    2017-12-31

    Large-scale ecological restoration has been widely accepted globally as an effective strategy for combating environmental crises and to facilitate sustainability. Assessing the effectiveness of ecological restoration is vital for researchers, practitioners, and policy-makers. However, few practical tools are available to perform such tasks, particularly for large-scale restoration programmes in complex socio-ecological systems. By taking a "before and after" design, this paper formulates a composite index (E j ) based on comparing the trends of vegetation cover and vegetation productivity to assess ecological restoration effectiveness. The index reveals the dynamic and spatially heterogenic process of vegetation restoration across different time periods, which can be informative for ecological restoration management at regional scales. Effectiveness together with its relationship to socio-economic factors is explored via structural equation modeling for three time periods. The results indicate that the temporal scale is a crucial factor in representing restoration effectiveness, and that the effects of socio-economic factors can also vary with time providing insight for improving restoration effectiveness. A dual-track strategy, which promotes the development of tertiary industry in absorbing the rural labor force together with improvements in agricultural practices, is proposed as a promising strategy for enhancing restoration effectiveness. In this process, timely and long-term ecological restoration monitoring is advocated, so that the success and sustainability of such programmes is ensured, together with more informative decision making where socio-ecological interactions at differing temporal scales are key concerns. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Effective action for composite operators and chiral symmetry breakdown in asymptotically free and non-asymptotically free gauge theories

    International Nuclear Information System (INIS)

    Gusynin, V.P.; Miranskij, V.A.

    1987-01-01

    An essential distinction in the relaization of the PCAC dynamics in asymptotically free and non-asymptotically free (with a non-trivial ultraviolet-stable fixed point) gauge theories is revealed. For the latter theories an analytical expressions for the condensate is obtained in the two-loop approximation and arguments of support of a soft behaviour at small distances of composite operators are given. The problem of factorizing the low-energy region for the Wess-Zumino-Witten action is discussed. Besides, the mass relations for pseudoscalar mesons in arbitrary Θ-sector are obtained in the first order in fermion bare masses and the impossibility for spontaneous P and CP-symmetries breaking in vector-like gauge theories at Θ=0 is shown

  17. On the Kählerian symmetries of the two-loop action of the effective string theory

    CERN Document Server

    Ozkurt, S S

    2003-01-01

    Sometimes ago, it has been proposed in a paper by N.Kaloper and K.A.Meissner (\\PR {\\bf D56} (1997) 7940) that if one makes local redefinitions of fields, it does not change the equations of motion (in the redefined fields); however, this comment has not generally been accepted, namely, the redefined fields satisfy different equations of motion. For this reason, in this paper, it is proved that the whole action can be written as a square of the zeroth-order field equations. In this way, we show that any solution of the zeroth-order field equations, which has some K\\"{a}hler symmetry, at the same time, is also a solution of the two-loop equations.

  18. System size and beam energy effects on probing the high-density behavior of nuclear symmetry energy with pion ratio

    International Nuclear Information System (INIS)

    Zhang Ming; Xiao Zhigang; Li Baoan; Chen Liewen; Yong Gaochan; Zhu Shengjiang

    2010-01-01

    Based on the isospin-and momentum-dependent hadronic transport model IBUU04, we have investigated the π - /π + ratio in the following three reactions: 48 Ca+ 48 Ca, 124 Sn + 124 Sn and 197 Au + 197 Au with nearly the same isospin asymmetry but different masses, at the bombarding energies from 0.25 to 0.6 AGeV. It is shown that the sensitivity of probing the E sym (ρ) with π - /π + increases with increasing the system size or decreasing the beam energy, showing a correlation to the degree of isospin fractionation. Therefore, with a given isospin asymmetry, heavier system at energies near the pion threshold is preferential to study the behavior of nuclear symmetry energy at supra-saturation densities.

  19. Effects of native forest restoration on soil hydraulic properties, Auwahi, Maui, Hawaiian Islands

    Science.gov (United States)

    Perkins, Kimberlie S.; Nimmo, John R.; Medeiros, Arthur C.

    2012-01-01

    Over historic time Hawai'i's dryland forests have been largely replaced by grasslands for grazing livestock. On-going efforts have been undertaken to restore dryland forests to bring back native species and reduce erosion. The reestablishment of native ecosystems on land severely degraded by long-term alternative use requires reversal of the impacts of erosion, organic-matter loss, and soil structural damage on soil hydraulic properties. This issue is perhaps especially critical in dryland forests where the soil must facilitate native plants' optimal use of limited water. These reforestation efforts depend on restoring soil ecological function, including soil hydraulic properties. We hypothesized that reforestation can measurably change soil hydraulic properties over restoration timescales. At a site on the island of Maui (Hawai'i, USA), we measured infiltration capacity, hydrophobicity, and abundance of preferential flow channels in a deforested grassland and in an adjacent area where active reforestation has been going on for fourteen years. Compared to the nearby deforested rangeland, mean field-saturated hydraulic conductivity in the newly restored forest measured by 55 infiltrometer tests was greater by a factor of 2.0. Hydrophobicity on an 8-point scale increased from average category 6.0 to 6.9. A 4-point empirical categorization of preferentiality in subsurface wetting patterns increased from an average 1.3 in grasslands to 2.6 in the restored forest. All of these changes act to distribute infiltrated water faster and deeper, as appropriate for native plant needs. This study indicates that vegetation restoration can lead to ecohydrologically important changes in soil hydraulic properties over decadal time scales.

  20. Detection of paleochannels using hydrogeophysical methods: An approach for more effective channel restoration

    Science.gov (United States)

    Altdorff, D.; Dietrich, P.; Epting, J.; Huggenberger, P.

    2011-12-01

    River restoration and applied restoration measures are of increasing importance for integrated water resources management (IWRM) as well as for ecosystem services including water storage and purification, habitat provision and climate regulation. However, often river restoration is planned and realized by engineering and constructing aspects only and hydrogeological settings and ancient stream dynamics are neglected. As a result desired outcomes of restoration projects are reduced with no significant alteration of stream conditions by simultaneously increasing costs. An opportunity to max out the restoration potential is to investigate ancient stream courses by applying hydrogeophysical methods as basis for targeted restoration measures. In this study, we investigate the paleochannel courses in a floodplain of a heavy modified low-mountain river in Switzerland by different hydrogeophysical methods. We use data from electromagnetic induction (EMI) with four different integral depths (0.75 to 6m) and gamma-spectrometry (GS) to generate a geological structure model (GSM) that allows delineating potential ancient stream courses. Thereby we derive the GSM iteratively by means of various electric conductivity (EC) forward models. We vary the geological input parameters based on the measured data until the synthetic EC maps fit to the real EC values. Then we incorporate the best fitted input data for a final GSM that shows the course of an ancient stream between the 2nd and 3rd layer (Fig 1). A comparison with a historical map shows good agreement with the situation before the river modification and also profiles from Ground Penetrating Radar (GPR) could generally confirm the obtained progression of ancient riverbed structures. The demonstrated iterative method is a tool for the characterization of test sites with no subsurface information and with the potential of detecting paleochannels.

  1. Symmetry of priapulids (Priapulida). 2. Symmetry of larvae.

    Science.gov (United States)

    Adrianov, A V; Malakhov, V V

    2001-02-01

    Larvae of priapulids are characterized by radial symmetry evident from both external and internal characters of the introvert and lorica. The bilaterality appears as a result of a combination of several radial symmetries: pentaradial symmetry of the teeth, octaradial symmetry of the primary scalids, 25-radial symmetry of scalids, biradial symmetry of the neck, and biradial and decaradial symmetry of the trunk. Internal radiality is exhibited by musculature and the circumpharyngeal nerve ring. Internal bilaterality is evident from the position of the ventral nerve cord and excretory elements. Externally, the bilaterality is determined by the position of the anal tubulus and two shortened midventral rows of scalids bordering the ventral nerve cord. The lorical elements define the biradial symmetry that is missing in adult priapulids. The radial symmetry of larvae is a secondary appearance considered an evolutionary adaptation to a lifestyle within the three-dimensional environment of the benthic sediment. Copyright 2001 Wiley-Liss, Inc.

  2. Evaluating indirect and direct effects of eco-restoration policy on soil conservation service in Yangtze River Basin.

    Science.gov (United States)

    Kong, Lingqiao; Zheng, Hua; Rao, Enming; Xiao, Yi; Ouyang, Zhiyun; Li, Cong

    2018-08-01

    The conservation impacts of policies that promote large-scale ecological restoration of ecosystem services and socio-economic development are well documented around the world. However, the effect of socio-economic development resulting from such policies on ecosystem services is rarely analysed, although it is important to do so if these policies are to be sustainable. We analysed the socio-economic impacts of soil conservation services from 2000 to 2015 in the Yangtze River Basin under the Grain to Green Programme (GTGP). Also we assessed the driving forces behind the programme: conservation policies, urbanization, agricultural development, and population growth. Our results show that during 2000-2015, cultivated area decreased by 7.5%, urban area increased by 67.5%, forest area increased by 2.1%, and soil erosion was reduced by 19.5%. The programme not only contributed significantly to an improvement in soil conservation services but also enhanced them significantly through faster urbanization. Furthermore, vegetation cover and crop yields increased synergistically, mainly due to high-efficiency agriculture that reduced the negative effect of the GTGP on agricultural production. Overall determining the indirect and direct effects of the GTGP on soil conservation and agricultural production are important for furthering our understanding of the long-term effects of ecological restoration policies, and the present study offers practical insights for ecological restoration of other watersheds. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Effect of Enamel and Dentin Irradiation by Gamma Rays on the Bond Strength of Two Adhesive Restorations

    International Nuclear Information System (INIS)

    Zein, N.S.A.

    2014-01-01

    and neck cancer patients subjected to radiotherapy represents a challenge for restorative dentistry. This is due to the high rates of caries found and the reduction in restoration longevity by restorative material deterioration and failure events that tend to occur rapidly(7). The use of adhesive restorative materials is recommended for the treatment of radiation caries. It has been reported that these tooth-colored restorations survive longer when they are provided with a good seal and protection against secondary caries (8). Unfortunately, the influence of radiotherapy, alone or followed by application of a desensitizing agent, on the bond strengths of these restorations has not been extensively evaluated. Therefore, the current study has been conducted to investigate the effect of enamel and dentin irradiation by gamma rays on the bond strength of two adhesive restorations and to investigate the effect of application of an amorphous calcium phosphate (ACP) desensitizing agent after irradiation and before restoration on the bond strength of the adhesive restorations

  4. Restoring forests

    DEFF Research Database (Denmark)

    Jacobs, Douglass F.; Oliet, Juan A.; Aronson, James

    2015-01-01

    of land requiring restoration implies the need for spatial prioritization of restoration efforts according to cost-benefit analyses that include ecological risks. To design resistant and resilient ecosystems that can adapt to emerging circumstances, an adaptive management approach is needed. Global change......, in particular, imparts a high degree of uncertainty about the future ecological and societal conditions of forest ecosystems to be restored, as well as their desired goods and services. We must also reconsider the suite of species incorporated into restoration with the aim of moving toward more stress resistant...... and competitive combinations in the longer term. Non-native species may serve an important role under some circumstances, e.g., to facilitate reintroduction of native species. Propagation and field establishment techniques must promote survival through seedling stress resistance and site preparation. An improved...

  5. Nanostructure symmetry: Relevance for physics and computing

    International Nuclear Information System (INIS)

    Dupertuis, Marc-André; Oberli, D. Y.; Karlsson, K. F.; Dalessi, S.; Gallinet, B.; Svendsen, G.

    2014-01-01

    We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented

  6. Nanostructure symmetry: Relevance for physics and computing

    Energy Technology Data Exchange (ETDEWEB)

    Dupertuis, Marc-André; Oberli, D. Y. [Laboratory for Physics of Nanostructure, EPF Lausanne (Switzerland); Karlsson, K. F. [Department of Physics, Chemistry, and Biology (IFM), Linköping University (Sweden); Dalessi, S. [Computational Biology Group, Department of Medical Genetics, University of Lausanne (Switzerland); Gallinet, B. [Nanophotonics and Metrology Laboratory, EPF Lausanne (Switzerland); Svendsen, G. [Dept. of Electronics and Telecom., Norwegian University of Science and Technology, Trondheim (Norway)

    2014-03-31

    We review the research done in recent years in our group on the effects of nanostructure symmetry, and outline its relevance both for nanostructure physics and for computations of their electronic and optical properties. The exemples of C3v and C2v quantum dots are used. A number of surprises and non-trivial aspects are outlined, and a few symmetry-based tools for computing and analysis are shortly presented.

  7. Rigidity and symmetry

    CERN Document Server

    Weiss, Asia; Whiteley, Walter

    2014-01-01

    This book contains recent contributions to the fields of rigidity and symmetry with two primary focuses: to present the mathematically rigorous treatment of rigidity of structures, and to explore the interaction of geometry, algebra, and combinatorics. Overall, the book shows how researchers from diverse backgrounds explore connections among the various discrete structures with symmetry as the unifying theme.  Contributions present recent trends and advances in discrete geometry, particularly in the theory of polytopes. The rapid development of abstract polytope theory has resulted in a rich theory featuring an attractive interplay of methods and tools from discrete geometry, group theory, classical geometry, hyperbolic geometry and topology.  The volume will also be a valuable source as an introduction to the ideas of both combinatorial and geometric rigidity theory and its applications, incorporating the surprising impact of symmetry. It will appeal to students at both the advanced undergraduate and gradu...

  8. Physics from symmetry

    CERN Document Server

    Schwichtenberg, Jakob

    2018-01-01

    This is a textbook that derives the fundamental theories of physics from symmetry. It starts by introducing, in a completely self-contained way, all mathematical tools needed to use symmetry ideas in physics. Thereafter, these tools are put into action and by using symmetry constraints, the fundamental equations of Quantum Mechanics, Quantum Field Theory, Electromagnetism, and Classical Mechanics are derived. As a result, the reader is able to understand the basic assumptions behind, and the connections between the modern theories of physics. The book concludes with first applications of the previously derived equations. Thanks to the input of readers from around the world, this second edition has been purged of typographical errors and also contains several revised sections with improved explanations. .

  9. Effects of seasonality, transport pathway, and spatial structure on greenhouse gas fluxes in a restored wetland.

    Science.gov (United States)

    McNicol, Gavin; Sturtevant, Cove S; Knox, Sara H; Dronova, Iryna; Baldocchi, Dennis D; Silver, Whendee L

    2017-07-01

    Wetlands can influence global climate via greenhouse gas (GHG) exchange of carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O). Few studies have quantified the full GHG budget of wetlands due to the high spatial and temporal variability of fluxes. We report annual open-water diffusion and ebullition fluxes of CO 2 , CH 4 , and N 2 O from a restored emergent marsh ecosystem. We combined these data with concurrent eddy-covariance measurements of whole-ecosystem CO 2 and CH 4 exchange to estimate GHG fluxes and associated radiative forcing effects for the whole wetland, and separately for open-water and vegetated cover types. Annual open-water CO 2 , CH 4 , and N 2 O emissions were 915 ± 95 g C-CO 2  m -2  yr -1 , 2.9 ± 0.5 g C-CH 4  m -2  yr -1 , and 62 ± 17 mg N-N 2 O m -2  yr -1 , respectively. Diffusion dominated open-water GHG transport, accounting for >99% of CO 2 and N 2 O emissions, and ~71% of CH 4 emissions. Seasonality was minor for CO 2 emissions, whereas CH 4 and N 2 O fluxes displayed strong and asynchronous seasonal dynamics. Notably, the overall radiative forcing of open-water fluxes (3.5 ± 0.3 kg CO 2 -eq m -2  yr -1 ) exceeded that of vegetated zones (1.4 ± 0.4 kg CO 2 -eq m -2  yr -1 ) due to high ecosystem respiration. After scaling results to the entire wetland using object-based cover classification of remote sensing imagery, net uptake of CO 2 (-1.4 ± 0.6 kt CO 2 -eq yr -1 ) did not offset CH 4 emission (3.7 ± 0.03 kt CO 2 -eq yr -1 ), producing an overall positive radiative forcing effect of 2.4 ± 0.3 kt CO 2 -eq yr -1 . These results demonstrate clear effects of seasonality, spatial structure, and transport pathway on the magnitude and composition of wetland GHG emissions, and the efficacy of multiscale flux measurement to overcome challenges of wetland heterogeneity. © 2017 John Wiley & Sons Ltd.

  10. Effect of meniscus replacement fixation technique on restoration of knee contact mechanics and stability.

    Science.gov (United States)

    D'Lima, D D; Chen, P C; Kessler, O; Hoenecke, H R; Colwell, C W

    2011-06-01

    The menisci are important biomechanical components of the knee. We developed and validated a finite element model of meniscal replacement to assess the effect of surgical fixation technique on contact behavior and knee stability. The geometry of femoral and tibial articular cartilage and menisci was segmented from magnetic resonance images of a normal cadaver knee using MIMICS (Materialise, Leuven, Belgium). A finite element mesh was generated using HyperWorks (Altair Inc, Santa Ana, CA). A finite element solver (Abaqus v6.9, Simulia, Providence, RI) was used to compute contact area and stresses under axial loading and to assess stability (reaction force generated during anteroposterior translation of the femur). The natural and surgical attachments of the meniscal horns and peripheral rim were simulated using springs. After total meniscectomy, femoral contact area decreased by 26% with a concomitant increase in average contact stresses (36%) and peak contact stresses (33%). Replacing the meniscus without suturing the horns did little to restore femoral contact area. Suturing the horns increased contact area and reduced peak contact stresses. Increasing suture stiffness correlated with increased meniscal contact stresses as a greater proportion of tibiofemoral load was transferred to the meniscus. A small incremental benefit was seen of simulated bone plug fixation over the suture construct with the highest stiffness (50 N/mm). Suturing the rim did little to change contact conditions. The nominal anteroposterior stiffness reduced by 3.1 N/mm after meniscectomy. In contrast to contact area and stress, stiffness of the horn fixation sutures had a smaller effect on anteroposterior stability. On the other hand suturing the rim of the meniscus affected anteroposterior stability to a much larger degree. This model emphasizes the importance of the meniscus in knee biomechanics. Appropriate meniscal replacement fixation techniques are likely to be critical to the clinical

  11. The Effect of Restoration Treatments on the Spatial Variability of Soil Processes under Longleaf Pine Trees

    Directory of Open Access Journals (Sweden)

    John K. Hiers

    2012-08-01

    Full Text Available The objectives of this study were to (1 characterize tree-based spatial patterning of soil properties and understory vegetation in frequently burned (“reference state” and fire-suppressed longleaf pine forests; and (2 determine how restoration treatments affected patterning. To attain these objectives, we used an experimental manipulation of management types implemented 15 years ago in Florida. We randomly located six mature longleaf pine trees in one reference and four restoration treatments (i.e., burn, control, herbicide, and mechanical, for a total of 36 trees. In addition to the original treatments and as part of a monitoring program, all plots were subjected to several prescribed fires during these 15 years. Under each tree, we sampled mineral soil and understory vegetation at 1 m, 2 m, 3 m and 4 m (vegetation only away from the tree. At these sites, soil carbon and nitrogen were higher near the trunk while graminoids, forbs and saw palmetto covers showed an opposite trend. Our results confirmed that longleaf pine trees affect the spatial patterning of soil and understory vegetation, and this patterning was mostly limited to the restoration sites. We suggest frequent burning as a probable cause for a lack of spatial structure in the “reference state”. We attribute the presence of spatial patterning in the restoration sites to accumulation of organic materials near the base of mature trees.

  12. Effects of sediment disturbance regimes on Spartina seedling establishment : Implications for salt marsh creation and restoration

    NARCIS (Netherlands)

    Cao, Haobing; Zhu, Zhenchang; Balke, Thorsten; Zhang, Liquan; Bouma, Tjeerd J.

    Seedling establishment is an important process relevant for the restoration of salt marsh within the framework of sustainable coastal defense schemes. Recent studies have increasingly highlighted how the short-term (i.e., the day-to-day) sediment dynamics can form major bottlenecks for seedling

  13. Long-term after-effects of fertilisation on restoration of calcareous grasslands

    NARCIS (Netherlands)

    Smits, N.A.C.; Bobbink, R.; Willems, J.H.

    2008-01-01

    Question: What are the long-term implications of former fertilisation for the ecological restoration of calcareous grasslands? Location: Gerendal, Limburg, The Netherlands. Methods: In 1970, ten permanent plots were established in just abandoned agricultural calcareous grassland under a regime of

  14. Genetic and environmental effects on seed weight in subspecies of big sagebrush: Applications for restoration

    Science.gov (United States)

    Bryce A. Richardson; Hector G. Ortiz; Stephanie L. Carlson; Deidre M. Jaeger; Nancy L. Shaw

    2015-01-01

    The sagebrush steppe is a patchwork of species and subspecies occupying distinct environmental niches across the intermountain regions of western North America. These ecosystems face degradation from disturbances and exotic weeds. Using sagebrush seed that is matched to its appropriate niche is a critical component to successful restoration, improving habitat for the...

  15. Effects of ecological restoration alternative treatments on nonnative plant species establishment

    Science.gov (United States)

    Michael T. Stoddard; Christopher M. McGlone; Peter Z. Fule

    2008-01-01

    Disturbances generated by forest restoration treatments have the potential for enhancing the establishment of nonnative species thereby impeding long-term native plant recovery. In a ponderosa pine forest next to the Fort Valley Experimental Forest, Arizona, we examined the establishment of nonnative species after three alternative treatments with different intensities...

  16. The effect of proximal contour on marginal ridge fracture of Class II composite resin restorations.

    NARCIS (Netherlands)

    Loomans, B.A.C.; Roeters, F.J.M.; Opdam, N.J.M.; Kuijs, R.H.

    2008-01-01

    OBJECTIVES: To compare the marginal ridge fracture strength of Class II composite resin restorations placed with a straight or contoured matrix band using composite resins with different modulus of elasticity. METHODS: In 60 artificial first molars standardized MO-preparations were ground. Two

  17. Symmetry, structure, and spacetime

    CERN Document Server

    Rickles, Dean

    2007-01-01

    In this book Rickles considers several interpretative difficulties raised by gauge-type symmetries (those that correspond to no change in physical state). The ubiquity of such symmetries in modern physics renders them an urgent topic in philosophy of physics. Rickles focuses on spacetime physics, and in particular classical and quantum general relativity. Here the problems posed are at their most pathological, involving the apparent disappearance of spacetime! Rickles argues that both traditional ontological positions should be replaced by a structuralist account according to which relational

  18. Symmetry and inflation

    International Nuclear Information System (INIS)

    Chimento, Luis P.

    2002-01-01

    We find the group of symmetry transformations under which the Einstein equations for the spatially flat Friedmann-Robertson-Walker universe are form invariant. They relate the energy density and the pressure of the fluid to the expansion rate. We show that inflation can be obtained from nonaccelerated scenarios by a symmetry transformation. We derive the transformation rule for the spectrum and spectral index of the curvature perturbations. Finally, the group is extended to investigate inflation in the anisotropic Bianchi type-I spacetime and the brane-world cosmology

  19. Dark matter and global symmetries

    Directory of Open Access Journals (Sweden)

    Yann Mambrini

    2016-09-01

    Full Text Available General considerations in general relativity and quantum mechanics are known to potentially rule out continuous global symmetries in the context of any consistent theory of quantum gravity. Assuming the validity of such considerations, we derive stringent bounds from gamma-ray, X-ray, cosmic-ray, neutrino, and CMB data on models that invoke global symmetries to stabilize the dark matter particle. We compute up-to-date, robust model-independent limits on the dark matter lifetime for a variety of Planck-scale suppressed dimension-five effective operators. We then specialize our analysis and apply our bounds to specific models including the Two-Higgs-Doublet, Left–Right, Singlet Fermionic, Zee–Babu, 3-3-1 and Radiative See-Saw models. Assuming that (i global symmetries are broken at the Planck scale, that (ii the non-renormalizable operators mediating dark matter decay have O(1 couplings, that (iii the dark matter is a singlet field, and that (iv the dark matter density distribution is well described by a NFW profile, we are able to rule out fermionic, vector, and scalar dark matter candidates across a broad mass range (keV–TeV, including the WIMP regime.

  20. Tracking gauge symmetry factorizability on intervals

    International Nuclear Information System (INIS)

    Ngoc-Khanh Tran

    2006-01-01

    We track the gauge symmetry breaking pattern by boundary conditions on fifth and higher-dimensional intervals. It is found that, with Dirichlet-Neumann boundary conditions, the Kaluza-Klein decomposition in five-dimension for arbitrary gauge group can always be factorized into that for separate subsets of at most two gauge symmetries, and so is completely solvable. Accordingly, we present a simple and systematic geometric method to unambiguously identify the gauge breaking/mixing content by general set of Dirichlet-Neumann boundary conditions. We then formulate a limit theorem on gauge symmetry factorizability to recapitulate this interesting feature. Albeit the breaking/mixing, a particularly simple check of orthogonality and normalization of fields' modes in effective 4-dim picture is explicitly obtained. An interesting chained-mixing of gauge symmetries in higher dimensions by Dirichlet-Neumann boundary conditions is also explicitly constructed. This study has direct applications to higgsless/GUT model building

  1. Effect of ecological restoration programs on dust concentrations in the North China Plain: a case study

    Science.gov (United States)

    Long, Xin; Tie, Xuexi; Li, Guohui; Cao, Junji; Feng, Tian; Zhao, Shuyu; Xing, Li; An, Zhisheng

    2018-05-01

    In recent decades, the Chinese government has made a great effort in initiating large-scale ecological restoration programs (ERPs) to reduce the dust concentrations in China, especially for dust storm episodes. Using the Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product, the ERP-induced land cover changes are quantitatively evaluated in this study. Two obvious vegetation protective barriers arise throughout China from the southwest to the northeast, which are well known as the Green Great Wall (GGW). Both the grass GGW and forest GGW are located between the dust source region (DSR) and the densely populated North China Plain (NCP). To assess the effect of ERPs on dust concentrations, a regional transport/dust model (WRF-DUST, Weather Research and Forecast model with dust) is applied to investigate the evolution of dust plumes during a strong dust storm episode from 2 to 8 March 2016. The WRF-DUST model generally performs reasonably well in reproducing the temporal variations and spatial distributions of near-surface [PMC] (mass concentration of particulate matter with aerodynamic diameter between 2.5 and 10 µm) during the dust storm event. Sensitivity experiments have indicated that the ERP-induced GGWs help to reduce the dust concentration in the NCP, especially in BTH (Beijing, Tianjin, and Hebei). When the dust storm is transported from the upwind DSR to the downwind NCP, the [PMC] reduction ranges from -5 to -15 % in the NCP, with a maximum reduction of -12.4 % (-19.2 µg m-3) in BTH and -7.6 % (-10.1 µg m-3) in the NCP. We find the dust plumes move up to the upper atmosphere and are transported from the upwind DSR to the downwind NCP, accompanied by dust decrease. During the episode, the forest GGW is nonsignificant in dust concentration control because it is of benefit for dry deposition and not for emission. Conversely, the grass GGW is beneficial in controlling dust erosion and is the dominant reason for [PMC] decrease in the NCP

  2. Effect of ecological restoration programs on dust concentrations in the North China Plain: a case study

    Directory of Open Access Journals (Sweden)

    X. Long

    2018-05-01

    Full Text Available In recent decades, the Chinese government has made a great effort in initiating large-scale ecological restoration programs (ERPs to reduce the dust concentrations in China, especially for dust storm episodes. Using the Moderate Resolution Imaging Spectroradiometer (MODIS land cover product, the ERP-induced land cover changes are quantitatively evaluated in this study. Two obvious vegetation protective barriers arise throughout China from the southwest to the northeast, which are well known as the Green Great Wall (GGW. Both the grass GGW and forest GGW are located between the dust source region (DSR and the densely populated North China Plain (NCP. To assess the effect of ERPs on dust concentrations, a regional transport/dust model (WRF-DUST, Weather Research and Forecast model with dust is applied to investigate the evolution of dust plumes during a strong dust storm episode from 2 to 8 March 2016. The WRF-DUST model generally performs reasonably well in reproducing the temporal variations and spatial distributions of near-surface [PMC] (mass concentration of particulate matter with aerodynamic diameter between 2.5 and 10 µm during the dust storm event. Sensitivity experiments have indicated that the ERP-induced GGWs help to reduce the dust concentration in the NCP, especially in BTH (Beijing, Tianjin, and Hebei. When the dust storm is transported from the upwind DSR to the downwind NCP, the [PMC] reduction ranges from −5 to −15 % in the NCP, with a maximum reduction of −12.4 % (−19.2 µg m−3 in BTH and −7.6 % (−10.1 µg m−3 in the NCP. We find the dust plumes move up to the upper atmosphere and are transported from the upwind DSR to the downwind NCP, accompanied by dust decrease. During the episode, the forest GGW is nonsignificant in dust concentration control because it is of benefit for dry deposition and not for emission. Conversely, the grass GGW is beneficial in controlling dust erosion and is the

  3. Ecological Restoration: Guidance from Theory

    Directory of Open Access Journals (Sweden)

    Joy Zedler

    2005-09-01

    Full Text Available A review of the science and practice of ecosystem restoration led me to identify key ecological theories and concepts that are relevant to planning, implementing, and sustaining restoration efforts. From experience with actual restoration projects, I provide guidance for improving the restoration process. Despite an abundance of theory and guidance, restoration goals are not always achieved, and pathways toward targets are not highly predictable. This is understandable, since each restoration project has many constraints and unique challenges. To improve restoration progress, I advise that sites be designed as experiments to allow learning while doing. At least the larger projects can be restored in phases, each designed as experimental treatments to test alternative restoration approaches. Subsequent phases can then adopt one or more of the treatments that best achieved goals in earlier phases while applying new tests of other restoration measures. Both science and restoration can progress simultaneously. This phased, experimental approach (called “adaptive restoration” is an effective tool for improving restoration when monitoring, assessment, interpretation and research are integrated into the process.

  4. Big break for charge symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Miller, G.A. [Department of Physics, University of Washington, Seattle (United States); Kolck, U. van [Department of Physics, University of Arizona, Tucson (United States)

    2003-06-01

    Two new experiments have detected charge-symmetry breaking, the mechanism responsible for protons and neutrons having different masses. Symmetry is a crucial concept in the theories that describe the subatomic world because it has an intimate connection with the laws of conservation. The theory of the strong interaction between quarks - quantum chromodynamics - is approximately invariant under what is called charge symmetry. In other words, if we swap an up quark for a down quark, then the strong interaction will look almost the same. This symmetry is related to the concept of {sup i}sospin{sup ,} and is not the same as charge conjugation (in which a particle is replaced by its antiparticle). Charge symmetry is broken by the competition between two different effects. The first is the small difference in mass between up and down quarks, which is about 200 times less than the mass of the proton. The second is their different electric charges. The up quark has a charge of +2/3 in units of the proton charge, while the down quark has a negative charge of -1/3. If charge symmetry was exact, the proton and the neutron would have the same mass and they would both be electrically neutral. This is because the proton is made of two up quarks and a down quark, while the neutron comprises two downs and an up. Replacing up quarks with down quarks, and vice versa, therefore transforms a proton into a neutron. Charge-symmetry breaking causes the neutron to be about 0.1% heavier than the proton because the down quark is slightly heavier than the up quark. Physicists had already elucidated certain aspects of charge-symmetry breaking, but our spirits were raised greatly when we heard of the recent work of Allena Opper of Ohio University in the US and co-workers at the TRIUMF laboratory in British Columbia, Canada. Her team has been trying to observe a small charge-symmetry-breaking effect for several years, using neutron beams at the TRIUMF accelerator. The researchers studied the

  5. The effect of repeated preheating of dimethacrylate and silorane-based composite resins on marginal gap of class V restorations.

    Science.gov (United States)

    Alizadeh Oskoee, Parnian; Pournaghi Azar, Fatemeh; Jafari Navimipour, Elmira; Ebrahimi Chaharom, Mohammad Esmaeel; Naser Alavi, Fereshteh; Salari, Ashkan

    2017-01-01

    Background. One of the problems with composite resin restorations is gap formation at resin‒tooth interface. The present study evaluated the effect of preheating cycles of silorane- and dimethacrylate-based composite resins on gap formation at the gingival margins of Class V restorations. Methods. In this in vitro study, standard Class V cavities were prepared on the buccal surfaces of 48 bovine incisors. For restorative procedure, the samples were randomly divided into 2 groups based on the type of composite resin (group 1: di-methacrylate composite [Filtek Z250]; group 2: silorane composite [Filtek P90]) and each group was randomly divided into 2 subgroups based on the composite temperature (A: room temperature; B: after 40 preheating cycles up to 55°C). Marginal gaps were measured using a stereomicroscope at ×40 and analyzed with two-way ANOVA. Inter- and intra-group comparisons were analyzed with post-hoc Tukey tests. Significance level was defined at P composite resin type, preheating and interactive effect of these variables on gap formation were significant (Pcomposite resins (Pcomposite resins at room temperature compared to composite resins after 40 preheating cycles (Pcomposite re-sins. Preheating of silorane-based composites can result in the best marginal adaptation.

  6. Zasada podwójnego skutku i zasada moralnej symetrii a kwestia legalizacji eutanazji [Principles of Double Effect and Moral Symmetry and Legalization of Euthanasia

    Directory of Open Access Journals (Sweden)

    Wacław Janikowski

    2013-06-01

    Full Text Available In this essay I scrutinize importance of Principles of Double Effect and MoralSymmetry in regard to the question of moral acceptance of euthanasia legalization.My conclusion is that although there is no substantially moral difference betweenpassive and active euthanasia, the problem of morally justifiable legalization ofeuthanasia is still not resolved. That is because some reasons suggest the possibilityof special discrepancy between moral acceptability of euthanasia in certain cases andmoral demand to preserve legal prohibition of euthanasia in general. In the paperI criticize the popular opinion that utilitarianism cannot account of why we giveweight to the question of moral permissibility of intentions. I claim that contraryto this false platitude utilitarianism can even accommodate practical relevance ofPrinciple of Double Effect, but not as a valid per se principle.

  7. Classical mirror symmetry

    CERN Document Server

    Jinzenji, Masao

    2018-01-01

    This book furnishes a brief introduction to classical mirror symmetry, a term that denotes the process of computing Gromov–Witten invariants of a Calabi–Yau threefold by using the Picard–Fuchs differential equation of period integrals of its mirror Calabi–Yau threefold. The book concentrates on the best-known example, the quintic hypersurface in 4-dimensional projective space, and its mirror manifold. First, there is a brief review of the process of discovery of mirror symmetry and the striking result proposed in the celebrated paper by Candelas and his collaborators. Next, some elementary results of complex manifolds and Chern classes needed for study of mirror symmetry are explained. Then the topological sigma models, the A-model and the B-model, are introduced. The classical mirror symmetry hypothesis is explained as the equivalence between the correlation function of the A-model of a quintic hyper-surface and that of the B-model of its mirror manifold. On the B-model side, the process of construct...

  8. Approximate symmetries of Hamiltonians

    Science.gov (United States)

    Chubb, Christopher T.; Flammia, Steven T.

    2017-08-01

    We explore the relationship between approximate symmetries of a gapped Hamiltonian and the structure of its ground space. We start by considering approximate symmetry operators, defined as unitary operators whose commutators with the Hamiltonian have norms that are sufficiently small. We show that when approximate symmetry operators can be restricted to the ground space while approximately preserving certain mutual commutation relations. We generalize the Stone-von Neumann theorem to matrices that approximately satisfy the canonical (Heisenberg-Weyl-type) commutation relations and use this to show that approximate symmetry operators can certify the degeneracy of the ground space even though they only approximately form a group. Importantly, the notions of "approximate" and "small" are all independent of the dimension of the ambient Hilbert space and depend only on the degeneracy in the ground space. Our analysis additionally holds for any gapped band of sufficiently small width in the excited spectrum of the Hamiltonian, and we discuss applications of these ideas to topological quantum phases of matter and topological quantum error correcting codes. Finally, in our analysis, we also provide an exponential improvement upon bounds concerning the existence of shared approximate eigenvectors of approximately commuting operators under an added normality constraint, which may be of independent interest.

  9. Molecular symmetry and spectroscopy

    CERN Document Server

    Bunker, Philip; Jensen, Per

    2006-01-01

    The first edition, by P.R. Bunker, published in 1979, remains the sole textbook that explains the use of the molecular symmetry group in understanding high resolution molecular spectra. Since 1979 there has been considerable progress in the field and a second edition is required; the original author has been joined in its writing by Per Jensen. The Material of the first edition has been reorganized and much has been added. The molecular symmetry group is now introduced early on, and the explanation of how to determine nuclear spin statistical weights has been consolidated in one chapter, after groups, symmetry groups, character tables and the Hamiltonian have been introduced. A description of the symmetry in the three-dimensional rotation group K(spatial), irreducible spherical tensor operators, and vector coupling coefficients is now included. The chapters on energy levels and selection rules contain a great deal of material that was not in the first edition (much of it was undiscovered in 1979), concerning ...

  10. The politics of symmetry

    NARCIS (Netherlands)

    Pels, D.L.

    While symmetry and impartiality have become ruling principles in S&TS, defining its core ideal of a 'value-free relativism', their philosophical anchorage has attracted much less discussion than the issue or:how far their jurisdiction can be extended or generalized. This paper seeks to argue that

  11. Symmetries in fundamental physics

    CERN Document Server

    Sundermeyer, Kurt

    2014-01-01

    Over the course of the last century it has become clear that both elementary particle physics and relativity theories are based on the notion of symmetries. These symmetries become manifest in that the "laws of nature" are invariant under spacetime transformations and/or gauge transformations. The consequences of these symmetries were analyzed as early as in 1918 by Emmy Noether on the level of action functionals. Her work did not receive due recognition for nearly half a century, but can today be understood as a recurring theme in classical mechanics, electrodynamics and special relativity, Yang-Mills type quantum field theories, and in general relativity. As a matter of fact, as shown in this monograph, many aspects of physics can be derived solely from symmetry considerations. This substantiates the statement of E.P.Wigner "... if we knew all the laws of nature, or the ultimate Law of nature, the invariance properties of these laws would not furnish us new information." Thanks to Wigner we now also underst...

  12. Symmetries in fundamental physics

    CERN Document Server

    Sundermeyer, Kurt

    2014-01-01

    Over the course of the last century it has become clear that both elementary particle physics and relativity theories are based on the notion of symmetries. These symmetries become manifest in that the "laws of nature" are invariant under spacetime transformations and/or gauge transformations. The consequences of these symmetries were analyzed as early as in 1918 by Emmy Noether on the level of action functionals. Her work did not receive due recognition for nearly half a century, but can today be understood as a recurring theme in classical mechanics, electrodynamics and special relativity, Yang-Mills type quantum field theories, and in general relativity. As a matter of fact, as shown in this monograph, many aspects of physics can be derived solely from symmetry considerations. This substantiates the statement of E.P. Wigner "... if we knew all the laws of nature, or the ultimate Law of nature, the invariance properties of these laws would not furnish us new information." Thanks to Wigner we now also unders...

  13. Groups and Symmetry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 10. Groups and Symmetry: A Guide to Discovering Mathematics. Geetha Venkataraman. Book Review Volume 4 Issue 10 October 1999 pp 91-92. Fulltext. Click here to view fulltext PDF. Permanent link:

  14. Aspects of W∞ symmetry

    International Nuclear Information System (INIS)

    Sezgin, E.

    1991-08-01

    We review the structure of W ∞ algebras, their super and topological extensions, and their contractions down to (super) w ∞ . Emphasis is put on the field theoretic realizations of these algebras. We also review the structure of w ∞ and W ∞ gravities and comment on various applications of W ∞ symmetry. (author). 42 refs

  15. Non-Noetherian symmetries

    International Nuclear Information System (INIS)

    Hojman, Sergio A.

    1996-01-01

    The purpose of these lectures is to present some of the ways in which non-Noetherian symmetries are used in contemporary mathematical physics. These include, among others, obtaining conservation laws for dynamical systems, solving non-linear problems, getting alternative Lagrangians for systems of differential equations and constructing symplectic structures and Hamiltonians for dynamical systems starting from scratch

  16. Detection symmetry and asymmetry

    NARCIS (Netherlands)

    du Buf, J.M.H.

    1991-01-01

    Experiments were performed on the detection symmetry and asymmetry of incremental and decremental disks, as a function of both disk diameter and duration. It was found that, for a background luminance of 300cd.m-2, thresholds of dynamic (briefly presented) foveal disks are symmetrical for all

  17. From symmetries to dynamics

    International Nuclear Information System (INIS)

    Stern, J.

    2000-01-01

    The problem of a uniform description of symmetries, their dynamic disturbing and the structure of the vacuum is discussed. The role which problems of this kind played in searching for and understanding the Standard Model of elementary particles from the 1960s till now is also highlighted. (Z.J.)

  18. Fields, symmetries, and quarks

    International Nuclear Information System (INIS)

    Mosel, U.

    1989-01-01

    'Fields, symmetries, and quarks' covers elements of quantum field theory, symmetries, gauge field theories and phenomenological descriptions of hadrons, with special emphasis on topics relevant to nuclear physics. It is aimed at nuclear physicists in general and at scientists who need a working knowledge of field theory, symmetry principles of elementary particles and their interactions and the quark structure of hadrons. The book starts out with an elementary introduction into classical field theory and its quantization. As gauge field theories require a working knowledge of global symmetries in field theories this topic is then discussed in detail. The following part is concerned with the general structure of gauge field theories and contains a thorough discussion of the still less widely known features of Non-Abelian gauge field theories. Quantum Chromodynamics (QCD), which is important for the understanding of hadronic matter, is discussed in the next section together with the quark compositions of hadrons. The last two chapters give a detailed discussion of phenomenological bag-models. The MIT bag is discussed, so that all theoretical calculations can be followed step by step. Since in all other bag-models the calculational methods and steps are essentially identical, this chapter should enable the reader to actually perform such calculations unaided. A last chapter finally discusses the topological bag-models which have become quite popular over the last few years. (orig.)

  19. [Effect of 2 methods of occlusion adjustment on occlusal balance and muscles of mastication in patient with implant restoration].

    Science.gov (United States)

    Wang, Rong; Xu, Xin

    2015-12-01

    To compare the effect of 2 methods of occlusion adjustment on occlusal balance and muscles of mastication in patients with dental implant restoration. Twenty patients, each with a single edentulous posterior dentition with no distal dentition were selected, and divided into 2 groups. Patients in group A underwent original occlusion adjustment method and patients in group B underwent occlusal plane reduction technique. Ankylos implants were implanted in the edentulous space in each patient and restored with fixed prosthodontics single unit crown. Occlusion was adjusted in each restoration accordingly. Electromyograms were conducted to determine the effect of adjustment methods on occlusion and muscles of mastication 3 months and 6 months after initial restoration and adjustment. Data was collected and measurements for balanced occlusal measuring standards were obtained, including central occlusion force (COF), asymmetry index of molar occlusal force(AMOF). Balanced muscles of mastication measuring standards were also obtained including measurements from electromyogram for the muscles of mastication and the anterior bundle of the temporalis muscle at the mandibular rest position, average electromyogram measurements of the anterior bundle of the temporalis muscle at the intercuspal position(ICP), Astot, masseter muscle asymmetry index, and anterior temporalis asymmetry index (ASTA). Statistical analysis was performed using Student 's t test with SPSS 18.0 software package. Three months after occlusion adjustment, parameters of the original occlusion adjustment method were significantly different between group A and group B in balanced occlusal measuring standards and balanced muscles of mastication measuring standards. Six months after occlusion adjustment, parameters of the original occlusion adjustment methods were significantly different between group A and group B in balanced muscles of mastication measuring standards, but was no significant difference in balanced

  20. Effectiveness of a lifestyle exercise program for older people receiving a restorative home care service: a pragmatic randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Burton E

    2013-12-01

    Full Text Available Elissa Burton,1,2 Gill Lewin,1,2 Lindy Clemson,3 Duncan Boldy41Faculty of Health Sciences, Curtin University, Perth, WA, Australia; 2Research Department, Silver Chain, Perth, WA, Australia; 3Health and Work Research Unit, The University of Sydney, Sydney, NSW, Australia; 4School of Nursing and Midwifery, Curtin University, Perth, WA, AustraliaBackground: Restorative home care services are short-term and aimed at maximizing a person’s ability to live independently. They are multidimensional and often include an exercise program to improve strength, mobility, and balance. The aim of this study was to determine whether a lifestyle exercise program would be undertaken more often and result in greater functional gains than the current structured exercise program delivered as part of a restorative home care service for older adults.Methods: A pragmatic randomized controlled trial was conducted in an organization with an established restorative home care service. Individuals who were to have an exercise program as part of their service were randomized to receive either a lifestyle and functional exercise program called LiFE (as this was a new program, the intervention or the structured exercise program currently being used in the service (control. Exercise data collected by the individuals throughout and pre and post intervention testing was used to measure balance, strength, mobility, falls efficacy, vitality, function, and disability.Results: There was no difference between the groups in the amounts of exercise undertaken during the 8-week intervention period. Outcome measurement indicated that the LiFE program was as effective, and on 40% of the measures, more effective, than the structured exercise program.Conclusion: Organizations delivering restorative home care services that include an exercise component should consider whether LiFE rather than the exercise program they are currently using could help their clients achieve better outcomes