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Sample records for effective one-electron description

  1. Effective one-electron approaches to calculate high harmonic generation

    NASA Astrophysics Data System (ADS)

    Rohringer, Nina; Santra, Robin

    2006-05-01

    The single-active electron approach (SAE) is frequently applied to calculate high harmonic generation in atoms and consists in solving a one-particle Schr"odinger equation in an appropriate model potential. As an ad hoc approach it is difficult to be systematically improved. Starting with the time-dependent configuration interaction singles (TDCIS) technique we derive a new class of effective one-electron approaches. The resulting one-electron equations are in general non-local and non-unitary. A local approximation to TDCIS can be derived by restricting the total many-body Hamiltonian to a local mean-field Hamiltonian (those usually used in SAE calculations). The resulting equations are similar to traditional SAE approaches but include an additional term which destroys the unitarity of the time-evolution. We show that this correction term is essential and improves on traditional SAE approaches. Numerical tests show that this improved SAE method gives dipole-moments in better agreement with exact results than time-dependent Hartree Fock. The test system is a one-dimensional model of helium which allows for a straightforward numerical solution and therefore provides a benchmark to assess the quality of the different approximations.

  2. Trimer effects in fragment molecular orbital-linear combination of molecular orbitals calculation of one-electron orbitals for biomolecules.

    PubMed

    Kobori, Tomoki; Sodeyama, Keitaro; Otsuka, Takao; Tateyama, Yoshitaka; Tsuneyuki, Shinji

    2013-09-07

    The fragment molecular orbital (FMO)-linear combination of molecular orbitals (LCMO) method incorporates as an efficient post-process calculation of one-electron orbitals of the whole system after the FMO total energy calculation. A straightforward way to increase the accuracy is inclusion of the trimer effect. Here, we derive a comprehensive formulation called the FMO3-LCMO method. To keep the computational costs of the trimer term low enough, we use a matrix-size reduction technique. We evaluated the accuracy and efficiency of the FMO3-LCMO scheme in model biological systems (alanine oligomer and chignolin). The results show that delocalized electronic orbitals with covalent and hydrogen bonds are better described at the trimer level, and the FMO3-LCMO method is applicable to quantitative evaluations of a wide range of frontier orbitals in large biosystems.

  3. Seebeck coefficient of one electron

    SciTech Connect

    Durrani, Zahid A. K.

    2014-03-07

    The Seebeck coefficient of one electron, driven thermally into a semiconductor single-electron box, is investigated theoretically. With a finite temperature difference ΔT between the source and charging island, a single electron can charge the island in equilibrium, directly generating a Seebeck effect. Seebeck coefficients for small and finite ΔT are calculated and a thermally driven Coulomb staircase is predicted. Single-electron Seebeck oscillations occur with increasing ΔT, as one electron at a time charges the box. A method is proposed for experimental verification of these effects.

  4. Charge-transfer (CT) orbitals for the one-electron description of CT excitations in a wide range of donor-acceptor separations

    NASA Astrophysics Data System (ADS)

    Gritsenko, O. V.

    2017-01-01

    A transformation of the virtual Kohn-Sham orbitals is proposed to a set of charge-transfer orbitals (CTOs) adapted to description of CT excitations. The CTO scheme offers a simple estimate of the CT excitation energy with an orbital energy difference. This estimate reproduces well the reference values of the configuration interaction (CI) method in a wide range of donor-acceptor separations in the paradigmatic He -Be complex. CTO-based orbital energy and shape indices are proposed to assess the suitability of the CT description with virtual orbitals of a given basis set. Both indices yield correct trends for the Kohn-Sham and Hartree-Fock orbitals.

  5. Charge transfer in collisions of the effectively-one-electron isocharged ions Si3+, C3+, and O3+ with atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Guevara, N. L.; Teixeira, E.; Hall, B.; Öhrn, Y.; Deumens, E.; Sabin, J. R.

    2011-05-01

    In a recent paper [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.77.064702 77, 064702 (2008)], Bruhns reported on an experimental investigation of charge transfer in collisions of Si3+ ions with atomic hydrogen and compared the energy dependence of the transfer cross sections with published theoretical results and with earlier experimental results for other effectively-one-electron isocharged ions, including C3+ and O3+. These authors observe that these three ions all have the structure of a single electron outside a closed subshell and thus might be expected to behave similarly. However, their results show quite different behavior, and they conclude that the influence of quantum-mechanical effects from the ionic core is clearly seen. We have investigated theoretically three collision systems, Si3+, C3+, and O3+ with atomic hydrogen, at projectile energies up to 10 keV/amu using the method of electron nuclear dynamics (END). In this paper we want to clarify and describe in some detail these quantum-mechanical effects by showing the time-dependent dynamics of the electrons during the collision of these three ions with atomic hydrogen. Total charge transfer cross sections were calculated for all three ions and compared with other theoretical and experimental results, showing good overall agreement. With this validation of the END description of the processes, we analyze the details of the computed dynamics of the electrons in each of the processes and illustrate the different mechanisms underlying observed differences in reaction outcomes.

  6. Nonspherical Potential due to Orbital Polarization and Its Effect in Atoms —Approach to Hund’s Second Rule in Terms of One-Electron Picture—

    NASA Astrophysics Data System (ADS)

    Narita, Akira

    2008-12-01

    The exchange-correlation functional composed of the Xα-exchange energy and the new type of correlation energy EM is assumed in order to study the effect of the nonspherical spatial distribution of electrons and the degeneracy of the total energy for states with the different ML values in the electronic open-shell configuration lN (l = p,d) of atom, where N is the number of electrons in the open shell characterized by directional quantum number l, ML is an expectation value of the z-component Lz of total angular momentum, and EM depends on ML. Nonspherical quantities such as electron density and one-electron effective potential are made from the partially filled occupation obeying Hund’s first rule in the open shell, and the Kohn-Sham equation is solved by the self-consistent degenerate first-order perturbation theory. Then, the parameters included in EM are succinctly and conveniently determined by imposing the appropriate conditions of degeneracy on the orbital and total energies. These methods are applied to the first-row and 3d transition atoms. Numerically self-consistent results, in which the final occupied orbitals agree with the starting ones used for the construction of electron density, are obtained, and the energies are reasonably acceptable since the occupied orbitals are more low-lying than the empty ones. Furthermore, the degeneracy of total energy with respect to ML is also obtained.

  7. One-electron versus electron-electron interaction contributions to the spin-spin coupling mechanism in nuclear magnetic resonance spectroscopy: analysis of basic electronic effects.

    PubMed

    Gräfenstein, Jürgen; Cremer, Dieter

    2004-12-22

    For the first time, the nuclear magnetic resonance (NMR) spin-spin coupling mechanism is decomposed into one-electron and electron-electron interaction contributions to demonstrate that spin-information transport between different orbitals is not exclusively an electron-exchange phenomenon. This is done using coupled perturbed density-functional theory in conjunction with the recently developed J-OC-PSP [=J-OC-OC-PSP: Decomposition of J into orbital contributions using orbital currents and partial spin polarization)] method. One-orbital contributions comprise Ramsey response and self-exchange effects and the two-orbital contributions describe first-order delocalization and steric exchange. The two-orbital effects can be characterized as external orbital, echo, and spin transport contributions. A relationship of these electronic effects to zeroth-order orbital theory is demonstrated and their sign and magnitude predicted using simple models and graphical representations of first order orbitals. In the case of methane the two NMR spin-spin coupling constants result from totally different Fermi contact coupling mechanisms. (1)J(C,H) is the result of the Ramsey response and the self-exchange of the bond orbital diminished by external first-order delocalization external one-orbital effects whereas (2)J(H,H) spin-spin coupling is almost exclusively mitigated by a two-orbital steric exchange effect. From this analysis, a series of prediction can be made how geometrical deformations, electron lone pairs, and substituent effects lead to a change in the values of (1)J(C,H) and (2)J(H,H), respectively, for hydrocarbons.

  8. An experimental comparison of the Marcus-Hush and Butler-Volmer descriptions of electrode kinetics applied to cyclic voltammetry. The one electron reductions of europium (III) and 2-methyl-2-nitropropane studied at a mercury microhemisphere electrode

    NASA Astrophysics Data System (ADS)

    Henstridge, Martin C.; Wang, Yijun; Limon-Petersen, Juan G.; Laborda, Eduardo; Compton, Richard G.

    2011-11-01

    We present a comparative experimental evaluation of the Butler-Volmer and Marcus-Hush models using cyclic voltammetry at a microelectrode. Numerical simulations are used to fit experimental voltammetry of the one electron reductions of europium (III) and 2-methyl-2-nitropropane, in water and acetonitrile, respectively, at a mercury microhemisphere electrode. For Eu (III) very accurate fits to experiment were obtained over a wide range of scan rates using Butler-Volmer kinetics, whereas the Marcus-Hush model was less accurate. The reduction of 2-methyl-2-nitropropane was well simulated by both models, however Marcus-Hush required a reorganisation energy lower than expected.

  9. One-electron oxidation of ferrocenes by short-lived N-oxyl radicals. The role of structural effects on the intrinsic electron transfer reactivities.

    PubMed

    Baciocchi, Enrico; Bietti, Massimo; D'Alfonso, Claudio; Lanzalunga, Osvaldo; Lapi, Andrea; Salamone, Michela

    2011-06-07

    A kinetic study of the one electron oxidation of substituted ferrocenes (FcX: X = H, COPh, COMe, CO(2)Et, CONH(2), CH(2)OH, Et, and Me(2)) by a series of N-oxyl radicals (succinimide-N-oxyl radical (SINO), maleimide-N-oxyl radical (MINO), 3-quinazolin-4-one-N-oxyl radical (QONO) and 3-benzotriazin-4-one-N-oxyl radical (BONO)), has been carried out in CH(3)CN. N-oxyl radicals were produced by hydrogen abstraction from the corresponding N-hydroxy derivatives by the cumyloxyl radical. With all systems, the rate constants exhibited a satisfactory fit to the Marcus equation allowing us to determine self-exchange reorganization energy values (λ(NO˙/NO(-))) which have been compared with those previously determined for the PINO/PINO(-) and BTNO/BTNO(-) couples. Even small modification of the structure of the N-oxyl radicals lead to significant variation of the λ(NO˙/NO(-)) values. The λ(NO˙/NO(-)) values increase in the order BONO < BTNO < QONO < PINO < SINO < MINO which do not parallel the order of the oxidation potentials. The higher λ(NO˙/NO(-)) values found for the MINO and SINO radicals might be in accordance with a lower degree of spin delocalization in the radicals MINO and SINO and charge delocalization in the anions MINO(-) and SINO(-) due to the absence of an aromatic ring in their structure.

  10. Consequence of one-electron oxidation and one-electron reduction for aniline.

    PubMed

    Raczyńska, Ewa D; Stępniewski, Tomasz M; Kolczyńska, Katarzyna

    2011-12-01

    Quantum-chemical calculations were performed for all possible isomers of neutral aniline and its redox forms, and intramolecular proton-transfer (prototropy) accompanied by π-electron delocalization was analyzed. One-electron oxidation (PhNH(2) - e → [PhNH(2)](+•)) has no important effect on tautomeric preferences. The enamine tautomer is preferred for oxidized aniline similarly as for the neutral molecule. Dramatical changes take place when proceeding from neutral to reduced aniline. One-electron reduction (PhNH(2) + e → [PhNH(2)](-•)) favors the imine tautomer. Independently on the state of oxidation, π- and n-electrons are more delocalized for the enamine than imine tautomers. The change of the tautomeric preferences for reduced aniline may partially explain the origin of the CH tautomers for reduced nucleobases (cytosine, adenine, and guanine).

  11. One-electron images in real space: natural adaptive orbitals.

    PubMed

    Menéndez, Marcos; Álvarez Boto, Roberto; Francisco, Evelio; Martín Pendás, Ángel

    2015-04-30

    We introduce a general procedure to construct a set of one-electron functions in chemical bonding theory, which remain physically sound both for correlated and noncorrelated electronic structure descriptions. These functions, which we call natural adaptive orbitals, decompose the n-center bonding indices used in real space theories of the chemical bond into one-electron contributions. For the n = 1 case, they coincide with the domain natural orbitals used in domain-averaged Fermi hole analyses. We examine their interpretation in the two-center case, and show how they behave and evolve in simple cases. Orbital pictures obtained through this technique converge onto the chemist's molecular orbital toolbox if electron correlation may be ignored, and provide new insight if it may not.

  12. One-electron physics of the actinides

    NASA Astrophysics Data System (ADS)

    Toropova, A.; Marianetti, C. A.; Haule, K.; Kotliar, G.

    2007-10-01

    We present a detailed analysis of the one-electron physics of the actinides. Various linear muffin-tin orbital basis sets are analyzed in order to determine a robust bare Hamiltonian for the actinides. The hybridization between f and spd states is compared with the f-f hopping in order to understand the Anderson-like and Hubbard-like contributions to itineracy in the actinides. We show that both contributions decrease strongly as one moves from the light actinides to the heavy actinides, while the Anderson-like contribution dominates in all cases. A real-space analysis of the band structure shows that nearest-neighbor hopping dominates the physics in these materials. Finally, we discuss the implications of our results to the delocalization transition as a function of atomic number across the actinide series.

  13. Effects of plant carotenoid spacers on the performance of a dye-sensitized solar cell using a chlorophyll derivative: Enhancement of photocurrent determined by one electron-oxidation potential of each carotenoid

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Feng; Matsuda, Arihiro; Koyama, Yasushi; Nagae, Hiroyoshi; Sasaki, Shin-ichi; Tamiaki, Hitoshi; Wada, Yuji

    2006-06-01

    Plant carotenoids (Cars) with 8-10 conjugated double bonds, having higher singlet energies than those of bacterial Cars with 9-13 conjugated double bonds, were added (by 20%) as redox spacers to a titania-based Grätzel-type solar cell using a chlorophyll derivative (PPB a) as the sensitizer. No clear indication of singlet-energy transfer from Car to PPB a was seen, but clear enhancement of photocurrent with the decreasing one electron-oxidation potential of Car was observed. An empirical equation correlating the increase in photocurrent to difference in one electron-oxidation potentials (PPB a minus Car) and the oscillator strength of Car is proposed.

  14. Generalized effective description of loop quantum cosmology

    NASA Astrophysics Data System (ADS)

    Ashtekar, Abhay; Gupt, Brajesh

    2015-10-01

    The effective description of loop quantum cosmology (LQC) has proved to be a convenient platform to study phenomenological implications of the quantum bounce that resolves the classical big bang singularity. Originally, this description was derived using Gaussian quantum states with small dispersions. In this paper we present a generalization to incorporate states with large dispersions. Specifically, we derive the generalized effective Friedmann and Raychaudhuri equations and propose a generalized effective Hamiltonian which are being used in an ongoing study of the phenomenological consequences of a broad class of quantum geometries. We also discuss an interesting interplay between the physics of states with larger dispersions in standard LQC, and of sharply peaked states in (hypothetical) LQC theories with larger area gap.

  15. Optical Hall effect-model description: tutorial.

    PubMed

    Schubert, Mathias; Kühne, Philipp; Darakchieva, Vanya; Hofmann, Tino

    2016-08-01

    The optical Hall effect is a physical phenomenon that describes the occurrence of magnetic-field-induced dielectric displacement at optical wavelengths, transverse and longitudinal to the incident electric field, and analogous to the static electrical Hall effect. The electrical Hall effect and certain cases of the optical Hall effect observations can be explained by extensions of the classic Drude model for the transport of electrons in metals. The optical Hall effect is most useful for characterization of electrical properties in semiconductors. Among many advantages, while the optical Hall effect dispenses with the need of electrical contacts, electrical material properties such as effective mass and mobility parameters, including their anisotropy as well as carrier type and density, can be determined from the optical Hall effect. Measurement of the optical Hall effect can be performed within the concept of generalized ellipsometry at an oblique angle of incidence. In this paper, we review and discuss physical model equations, which can be used to calculate the optical Hall effect in single- and multiple-layered structures of semiconductor materials. We define the optical Hall effect dielectric function tensor, demonstrate diagonalization approaches, and show requirements for the optical Hall effect tensor from energy conservation. We discuss both continuum and quantum approaches, and we provide a brief description of the generalized ellipsometry concept, the Mueller matrix calculus, and a 4×4 matrix algebra to calculate data accessible by experiment. In a follow-up paper, we will discuss strategies and approaches for experimental data acquisition and analysis.

  16. An effective description of the landscape

    SciTech Connect

    Gallego, Diego

    2010-02-10

    We study under what conditions the Two-Step moduli stabilization is a reliable description of the low energy effective action. We focus on a general class of models whose superpotential mimics the typical one describing supergravity theories from superstring compactifications with background fluxes. We find that the procedure is a reliable one as far as a mass hierarchy of order M{sub S}/M{sub P}, M{sub S} the supersymmetry breaking scale, is realized. This contribution is based on [1, 2].

  17. On the consistent definition of spin-orbit effects calculated by relativistic effective core potentials with one-electron spin-orbit operators: Comparison of spin-orbit effects for Tl, TlH, TlH3, PbH2, and PbH4

    NASA Astrophysics Data System (ADS)

    Han, Young-Kyu; Bae, Cheolbeom; Lee, Yoon Sup

    1999-05-01

    The spin-orbit effects for Tl, TlH, TlH3, PbH2, and PbH4 are evaluated by two-component calculations using several relativistic effective core potentials (RECP) with one-electron spin-orbit operators. The used RECPs are shape-consistent RECPs derived by Wildman et al. [J. Chem. Phys. 107, 9975 (1997)] and three sets of energy-consistent (or adjusted) RECPs published by Schwerdtfeger et al. [Phys. Scr. 36, 453 (1987); J. Chem. Phys. 90, 762 (1989)], Küchle et al. [Mol. Phys. 74, 1245 (1991)], and Leininger et al. [Chem. Phys. 217, 19 (1997)]. The shape-consistent RECP results are in very good agreement with the Küchle et al. energy-consistent RECP results for all the molecules studied here and all-electron results for TlH. The RECPs of Schwerdtfeger et al. and Leininger et al. seem to provide qualitatively different spin-orbit effects. If one defines spin-free RECP as the potential average of the corresponding two-component RECP, all RECPs give very similar spin-orbit effects for all the cases. Most of the discrepancies of molecular spin-orbit effects among various RECPs reported in the literature may originate from different definitions of RECPs with or without a spin-orbit term and not from the inherent difference in spin-orbit operators.

  18. Improved inequalities for one-electron moments of r

    NASA Astrophysics Data System (ADS)

    Brownstein, K. R.

    1994-01-01

    Let =∫r kρr 2 dr be the kth moment of r for the one-electron radial density ρ(r). One obtains improved (Schwarz-like) inequalities for these moments if ρ is Nth-order monotonic, i.e., if dNρ/dr n is of one sign. These are of the form ≥GN(a,b), where GN(a,b) increases with N. In particular for (a,b)=(1,-1), one obtains G0=1 (Schwarz inequality), G1=9/8 (as obtained by Gadre), and G∞=3/2 in the limit N→∞. One also obtains similarly improved (Gram-like) determinantal inequalities for r moments in terms of the order of monotonicity N. Several examples using published r moments are presented.

  19. One-electron transfer reactions of the couple NAD. /NADH. [Pulse radiolysis

    SciTech Connect

    Grodkowski, J.; Neta, P.; Carlson, B.W.; Miller, L.

    1983-08-04

    One-electron transfer reactions involving nicotinamide-adenine dinucleotide in its oxidized and reducd forms (NAD./NADH) were studied by pulse radiolysis in aqueous solutions. One-electron oxidation of NADH by various phenoxyl radicals and phenothiazine cation radicals was found to take place with rate constants in the range of 10/sup 5/ to 10/sup 8/ M/sup -1/ s/sup -1/, depending on the redox potential of the oxidizing species. In all cases, NAD. is formed quantitatively with no indication for the existence of the protonated form (NADH/sup +/.). The spectrum of NAD., as well as the rates of oxidation of NADH by phenoxyl and by (chlorpromazine)/sup +/. were independent of pH between pH 4.5 and 13.5. Reaction of deuterated NADH indicated only a small kinetic isotope effect. All these findings point to an electron transfer mechanism. On the other hand, attempts to observe the reverse electron transfer, i.e., one-electron reduction of NAD. to NADH by radicals such as semiquinones, showed that k was less than 10/sup 4/ to 10/sup 5/ M/sup -1/ s/sup -1/, so that it was unobservable. Consequently, it was not possible to achieve equilibrium conditions which would have permitted the direct measurement of the redox potential for NAD./NADH. One-electron reduction of NAD. appears to be an unlikely process. 1 table.

  20. Effective string description of confining flux tubes

    NASA Astrophysics Data System (ADS)

    Brandt, Bastian B.; Meineri, Marco

    2016-08-01

    We review the current knowledge about the theoretical foundations of the effective string theory for confining flux tubes and the comparison of the predictions to pure gauge lattice data. A concise presentation of the effective string theory is provided, incorporating recent developments. We summarize the predictions for the spectrum and the profile/width of the flux tube and their comparison to lattice data. The review closes with a short summary of open questions for future research.

  1. Effective field theory description of halo nuclei

    NASA Astrophysics Data System (ADS)

    Hammer, H.-W.; Ji, C.; Phillips, D. R.

    2017-10-01

    Nuclear halos emerge as new degrees of freedom near the neutron and proton driplines. They consist of a core and one or a few nucleons which spend most of their time in the classically-forbidden region outside the range of the interaction. Individual nucleons inside the core are thus unresolved in the halo configuration, and the low-energy effective interactions are short-range forces between the core and the valence nucleons. Similar phenomena occur in clusters of 4He atoms, cold atomic gases near a Feshbach resonance, and some exotic hadrons. In these weakly-bound quantum systems universal scaling laws for s-wave binding emerge that are independent of the details of the interaction. Effective field theory (EFT) exposes these correlations and permits the calculation of non-universal corrections to them due to short-distance effects, as well as the extension of these ideas to systems involving the Coulomb interaction and/or binding in higher angular-momentum channels. Halo nuclei exhibit all these features. Halo EFT, the EFT for halo nuclei, has been used to compute the properties of single-neutron, two-neutron, and single-proton halos of s-wave and p-wave type. This review summarizes these results for halo binding energies, radii, Coulomb dissociation, and radiative capture, as well as the connection of these properties to scattering parameters, thereby elucidating the universal correlations between all these observables. We also discuss how Halo EFT's encoding of the long-distance physics of halo nuclei can be used to check and extend ab initio calculations that include detailed modeling of their short-distance dynamics.

  2. Quantum calculation of the second-order hyperpolarizability of chiral molecules in the "one-electron" model.

    PubMed

    Hache, F

    2010-09-23

    Quantum calculation of the hyperpolarizabilty tensor is carried out for chiral molecules displaying a "one-electron" chirality. Calculation is made possible by introducing a chiral perturbation term in the potential energy surface. We show that a one-electron chiral molecule is intrinsically nonlinear and diplays a nonzero electric chiral hyperpolarizability. Existence of magnetic contributions is discussed, and it is shown that higher-order perturbation terms are necessary to introduce such magnetic effects in the second-order hyperpolarizability.

  3. Effect of descriptive information and experience on automation reliance.

    PubMed

    Yuviler-Gavish, Nirit; Gopher, Daniel

    2011-06-01

    The present research addresses the issue of reliance on decision support systems for the long-term (DSSLT), which help users develop decision-making strategies and long-term planning. It is argued that providing information about a system's future performance in an experiential manner, as compared with a descriptive manner, encourages users to increase their reliance level. Establishing appropriate reliance on DSSLT is contingent on the system developer's ability to provide users with information about the system's future performance. A sequence of three studies contrasts the effect on automation reliance of providing descriptive information versus experience for DSSLT with two different positive expected values of recommendations. Study I demonstrated that when automation reliance was determined solely on the basis of description, it was relatively low, but it increased significantly when a decision was made after experience with 50 training simulations. Participants were able to learn to increase their automation reliance levels when they encountered the same type of recommendation again. Study 2 showed that the absence of preliminary descriptive information did not affect the automation reliance levels obtained after experience. Study 3 demonstrated that participants were able to generalize their learning about increasing reliance levels to new recommendations. Using experience rather than description to give users information about future performance in DSSLT can help increase automation reliance levels. Implications for designing DSSLT and decision support systems in general are discussed.

  4. One-electron oxidation of 2-(4-methoxyphenyl)-2-methylpropanoic and 1-(4-methoxyphenyl)cyclopropanecarboxylic acids in aqueous solution. the involvement of radical cations and the influence of structural effects and pH on the side-chain fragmentation reactivity.

    PubMed

    Bietti, Massimo; Capone, Alberto

    2008-01-18

    A product and time-resolved kinetic study on the one-electron oxidation of 2-(4-methoxyphenyl)-2-methylpropanoic acid (2), 1-(4-methoxyphenyl)cyclopropanecarboxylic acid (3), and of the corresponding methyl esters (substrates 4 and 5, respectively) has been carried out in aqueous solution. With 2, no direct evidence for the formation of an intermediate radical cation 2*+ but only of the decarboxylated 4-methoxycumyl radical has been obtained, indicating either that 2*+ is not formed or that its decarboxylation is too fast to allow detection under the experimental conditions employed (k > 1 x 10(7) s(-1)). With 3, oxidation leads to the formation of the corresponding radical cation 3*+ or radical zwitterion -3*+ depending on pH. At pH 1.0 and 6.7, 3*+ and -3*+ have been observed to undergo decarboxylation as the exclusive side-chain fragmentation pathway with rate constants k = 4.6 x 10(3) and 2.3 x 10(4) s(-1), respectively. With methyl esters 4 and 5, direct evidence for the formation of the corresponding radical cations 4*+ and 5*+ has been obtained. Both radical cations have been observed to display a very low reactivity and an upper limit for their decay rate constants has been determined as k < 10(3) s(-1). Comparison between the one-electron oxidation reactions of 2 and 3 shows that the replacement of the C(CH3)2 moiety with a cyclopropyl group determines a decrease in decarboxylation rate constant of more than 3 orders of magnitude. This large difference in reactivity has been qualitatively explained in terms of three main contributions: substrate oxidation potential, stability of the carbon-centered radical formed after decarboxylation, and stereoelectronic effects. In basic solution, -3*+ and 5*+ have been observed to react with -OH in a process that is assigned to the -OH-induced ring-opening of the cyclopropane ring, and the corresponding second-order rate constants (k-OH) have been obtained. With -3*+, competition between decarboxylation and -OH

  5. Molecular structural formulas as one-electron density and hamiltonian operators: the VIF method extended.

    PubMed

    Alia, Joseph D

    2007-03-29

    The valency interaction formula (VIF) method is given a broader and more general interpretation in which these simple molecular structural formulas implicitly include all overlaps between valence atomic orbitals even for interactions not drawn in the VIF picture. This applies for VIF pictures as one-electron Hamiltonian operators as well as VIF pictures as one-electron density operators that constitute a new implementation of the VIF method simpler in its application and more accurate in its results than previous approaches. A procedure for estimating elements of the effective charge density-bond order matrix, Pmunu, from electron configurations in atoms is presented, and it is shown how these lead to loop and line constants in the VIF picture. From these structural formulas, one finds the number of singly, doubly, and unoccupied molecular orbitals, as well as the number of molecular orbitals with energy lower, equal, and higher than -1/2Eh, the negative of the hydrogen atom's ionization energy. The VIF results for water are in qualitative agreement with MP2/6311++G3df3pd, MO energy levels where the simple VIF for water presented in the earlier literature does not agree with computed energy levels. The method presented here gives the simplest accurate VIF pictures for hydrocarbons. It is shown how VIF can be used to predict thermal barriers to chemical reactions. Insertion of singlet carbene into H2 is given as an example. VIF pictures as one-electron density operators describe the ground-state multiplicities of B2, N2, and O2 molecules and as one-electron Hamiltonian operators give the correct electronegativity trend across period two. Previous implementations of VIF do not indicate singly occupied molecular orbitals directly from the pictorial VIF rules for these examples. The direct comparison between structural formulas that represent electron density and those that represent energy is supported by comparison of a simple electronegativity scale, chiD=N/n2, with

  6. Effective description of the interaction between anisotropic viscous fingers

    NASA Astrophysics Data System (ADS)

    Pecelerowicz, Michal; Budek, Agnieszka; Szymczak, Piotr

    2014-10-01

    We study patterns formed by viscous fingering in a rectangular network of microfluidic channels. Due to the strong anisotropy of such a system, the emerging patterns have a form of thin needle-like fingers, which interact with each other, competing for an available flow. We develop an upscaled description of this system in which only the fingers are tracked and the effective interactions between them are introduced, mediated through the evolving pressure field. Due to the quasi-2d geometry of the system, this is conveniently accomplished using conformal mapping techniques. A complex two-phase flow problem is thus reduced to a much simpler task of tracking evolving shapes in a 2d complex plane. This description, although simplified, turns out to capture all the key features of the system's dynamics and allows for the effective prediction of the resulting growth patterns.

  7. One-electron oxidation reactions of purine and pyrimidine bases in cellular DNA

    PubMed Central

    Cadet, Jean; Wagner, J. Richard; Shafirovich, Vladimir; Geacintov, Nicholas E.

    2014-01-01

    Purpose The aim of this survey is to critically review the available information on one-electron oxidation reactions of nucleobases in cellular DNA with emphasis on damage induced through the transient generation of purine and pyrimidine radical cations. Since the indirect effect of ionizing radiation mediated by hydroxyl radical is predominant in cells, efforts have been made to selectively ionize bases using suitable one-electron oxidants that consist among others of high intensity UVC laser pulses. Thus, the main oxidation product in cellular DNA was found to be 8-oxo-7,8-dihydroguanine as a result of direct bi-photonic ionization of guanine bases and indirect formation of guanine radical cations through hole transfer reactions from other base radical cations. The formation of 8-oxo-7,8-dihydroguanine and other purine and pyrimidine degradation products was rationalized in terms of the initial generation of related radical cations followed by either hydration or deprotonation reactions in agreement with mechanistic pathways inferred from detailed mechanistic studies. The guanine radical cation has been shown to be implicated in three other nucleophilic additions that give rise to DNA-protein and DNA-DNA cross-links in model systems. Evidence was recently provided for the occurrence of these three reactions in cellular DNA. Conclusion There is growing evidence that one-electron oxidation reactions of nucleobases whose mechanisms have been characterized in model studies involving aqueous solutions take place in a similar way in cells. It may also be pointed out that the above cross-linked lesions are only produced from the guanine radical cation and may be considered as diagnostic products of the direct effect of ionizing radiation. PMID:24369822

  8. The anchor integration model: A descriptive model of anchoring effects.

    PubMed

    Turner, Brandon M; Schley, Dan R

    2016-11-01

    Few experimental effects in the psychology of judgment and decision making have been studied as meticulously as the anchoring effect. Although the existing literature provides considerable insight into the psychological processes underlying anchoring effects, extant theories up to this point have only generated qualitative predictions. While these theories have been productive in advancing our understanding of the underlying anchoring process, they leave much to be desired in the interpretation of specific anchoring effects. In this article, we introduce the Anchor Integration Model (AIM) as a descriptive tool for the measurement and quantification of anchoring effects. We develop two versions the model: one suitable for assessing between-participant anchoring effects, and another for assessing individual differences in anchoring effects. We then fit each model to data from two experiments, and demonstrate the model's utility in describing anchoring effects. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Analytical Description of Mutational Effects in Competing Asexual Populations

    PubMed Central

    Pinkel, Daniel

    2007-01-01

    The adaptation of a population to a new environment is a result of selection operating on a suite of stochastically occurring mutations. This article presents an analytical approach to understanding the population dynamics during adaptation, specifically addressing a system in which periods of growth are separated by selection in bottlenecks. The analysis derives simple expressions for the average properties of the evolving population, including a quantitative description of progressive narrowing of the range of selection coefficients of the predominant mutant cells and of the proportion of mutant cells as a function of time. A complete statistical description of the bottlenecks is also presented, leading to a description of the stochastic behavior of the population in terms of effective mutation times. The effective mutation times are related to the actual mutation times by calculable probability distributions, similar to the selection coefficients being highly restricted in their probable values. This analytical approach is used to model recently published experimental data from a bacterial coculture experiment, and the results are compared to those of a numerical model published in conjunction with the data. Finally, experimental designs that may improve measurements of fitness distributions are suggested. PMID:17947437

  10. From information theory to quantitative description of steric effects.

    PubMed

    Alipour, Mojtaba; Safari, Zahra

    2016-07-21

    Immense efforts have been made in the literature to apply the information theory descriptors for investigating the electronic structure theory of various systems. In the present study, the information theoretic quantities, such as Fisher information, Shannon entropy, Onicescu information energy, and Ghosh-Berkowitz-Parr entropy, have been used to present a quantitative description for one of the most widely used concepts in chemistry, namely the steric effects. Taking the experimental steric scales for the different compounds as benchmark sets, there are reasonable linear relationships between the experimental scales of the steric effects and theoretical values of steric energies calculated from information theory functionals. Perusing the results obtained from the information theoretic quantities with the two representations of electron density and shape function, the Shannon entropy has the best performance for the purpose. On the one hand, the usefulness of considering the contributions of functional groups steric energies and geometries, and on the other hand, dissecting the effects of both global and local information measures simultaneously have also been explored. Furthermore, the utility of the information functionals for the description of steric effects in several chemical transformations, such as electrophilic and nucleophilic reactions and host-guest chemistry, has been analyzed. The functionals of information theory correlate remarkably with the stability of systems and experimental scales. Overall, these findings show that the information theoretic quantities can be introduced as quantitative measures of steric effects and provide further evidences of the quality of information theory toward helping theoreticians and experimentalists to interpret different problems in real systems.

  11. Oxygen dependency of one-electron reactions generating ascorbate radicals and hydrogen peroxide from ascorbic acid.

    PubMed

    Boatright, William L

    2016-04-01

    The effect of oxygen on the two separate one-electron reactions involved in the oxidation of ascorbic acid was investigated. The rate of ascorbate radical (Asc(-)) formation (and stability) was strongly dependent on the presence of oxygen. A product of ascorbic acid oxidation was measurable levels of hydrogen peroxide, as high as 32.5 μM from 100 μM ascorbic acid. Evidence for a feedback mechanism where hydrogen peroxide generated during the oxidation of ascorbic acid accelerates further oxidation of ascorbic acid is also presented. The second one-electron oxidation reaction of ascorbic acid leading to the disappearance of Asc(-) was also strongly inhibited in samples flushed with argon. In the range of 0.05-1.2 mM ascorbic acid, maximum levels of measurable hydrogen peroxide were achieved with an initial concentration of 0.2 mM ascorbic acid. Hydrogen peroxide generation was greatly diminished at ascorbic acid levels of 0.8 mM or above. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Nonsingular bouncing cosmology: Consistency of the effective description

    NASA Astrophysics Data System (ADS)

    Koehn, Michael; Lehners, Jean-Luc; Ovrut, Burt

    2016-05-01

    We explicitly confirm that spatially flat nonsingular bouncing cosmologies make sense as effective theories. The presence of a nonsingular bounce in a spatially flat universe implies a temporary violation of the null energy condition, which can be achieved through a phase of ghost condensation. We calculate the scale of strong coupling and demonstrate that the ghost-condensate bounce remains trustworthy throughout, and that all perturbation modes within the regime of validity of the effective description remain under control. For this purpose we require the perturbed action up to third order in perturbations, which we calculate in both flat and co-moving gauge—since these two gauges allow us to highlight different physical aspects. Our conclusion is that there exist healthy descriptions of nonsingular bouncing cosmologies providing a viable resolution of the big-bang singularities in cosmological models. Our results also suggest a variant of ekpyrotic cosmology, in which entropy perturbations are generated during the contracting phase, but are only converted into curvature perturbations after the bounce.

  13. The source effect: person descriptions by self versus others have differential effects on impression formation.

    PubMed

    Brandt, Aafje C; Vonk, Roos; van Knippenberg, Ad

    2009-07-01

    Self-presentation via favorable self-descriptions may not lead to the desired impression, whereas positive descriptions by others may be more effective because they seem less susceptible to motivated bias. In four experiments, we investigated whether person descriptions have more impact on impressions when provided by third parties than by targets themselves. Results showed that target impressions were consistently more in line with the target description when positive sociability-related or positive competency-related information was given by a third party than by the target. This source effect always occurred for ratings of claimed traits. In addition, ratings of the target's sociability were also affected when the claim was about competency. Source effects were not obtained for negative self-descriptions. The results are discussed in terms of the presumed underlying process on the basis of mediation data.

  14. Zeeman energy and spin relaxation in a one-electron quantum dot.

    PubMed

    Hanson, R; Witkamp, B; Vandersypen, L M K; van Beveren, L H Willems; Elzerman, J M; Kouwenhoven, L P

    2003-11-07

    We have measured the relaxation time, T1, of the spin of a single electron confined in a semiconductor quantum dot (a proposed quantum bit). In a magnetic field, applied parallel to the two-dimensional electron gas in which the quantum dot is defined, Zeeman splitting of the orbital states is directly observed by measurements of electron transport through the dot. By applying short voltage pulses, we can populate the excited spin state with one electron and monitor relaxation of the spin. We find a lower bound on T1 of 50 micros at 7.5 T, only limited by our signal-to-noise ratio. A continuous measurement of the charge on the dot has no observable effect on the spin relaxation.

  15. Bridging the macroscopic and atomistic descriptions of the electrocaloric effect.

    PubMed

    Ponomareva, I; Lisenkov, S

    2012-04-20

    First-principles-based simulations are used to simulate the electrocaloric effect (ECE) in Ba(0.5)Sr(0.5)TiO(3) alloys. In analogy with experimental studies we simulate the effect directly and indirectly (via the use of Maxwell thermodynamics). Both direct and indirect simulations utilize the same atomistic framework that allows us to compare them in a systematic way and with an atomistic precision for the very first time. Such precise comparison allows us to provide a bridge between the atomistic and macroscopic descriptions of the ECE and identify the factors that may critically compromise or even destroy their equivalence. Our computational data reveal the intrinsic features of ECE in ferroelectrics with multiple ferroelectric transitions and confirm the potential of these materials to exhibit giant electrocaloric response. The coexistence of negative and positive ECE in one material as well as an unusual field-driven transition between them is predicted, explained at an atomistic level, and proposed as a potential way to enhance the electrocaloric efficiency.

  16. Bridging the Macroscopic and Atomistic Descriptions of the Electrocaloric Effect

    NASA Astrophysics Data System (ADS)

    Ponomareva, I.; Lisenkov, S.

    2012-04-01

    First-principles-based simulations are used to simulate the electrocaloric effect (ECE) in Ba0.5Sr0.5TiO3 alloys. In analogy with experimental studies we simulate the effect directly and indirectly (via the use of Maxwell thermodynamics). Both direct and indirect simulations utilize the same atomistic framework that allows us to compare them in a systematic way and with an atomistic precision for the very first time. Such precise comparison allows us to provide a bridge between the atomistic and macroscopic descriptions of the ECE and identify the factors that may critically compromise or even destroy their equivalence. Our computational data reveal the intrinsic features of ECE in ferroelectrics with multiple ferroelectric transitions and confirm the potential of these materials to exhibit giant electrocaloric response. The coexistence of negative and positive ECE in one material as well as an unusual field-driven transition between them is predicted, explained at an atomistic level, and proposed as a potential way to enhance the electrocaloric efficiency.

  17. Microscopic description of production cross sections including deexcitation effects

    NASA Astrophysics Data System (ADS)

    Sekizawa, Kazuyuki

    2017-07-01

    Background: At the forefront of the nuclear science, production of new neutron-rich isotopes is continuously pursued at accelerator laboratories all over the world. To explore the currently unknown territories in the nuclear chart far away from the stability, reliable theoretical predictions are inevitable. Purpose: To provide a reliable prediction of production cross sections taking into account secondary deexcitation processes, both particle evaporation and fission, a new method called TDHF+GEMINI is proposed, which combines the microscopic time-dependent Hartree-Fock (TDHF) theory with a sophisticated statistical compound-nucleus deexcitation model, GEMINI++. Methods: Low-energy heavy ion reactions are described based on three-dimensional Skyrme-TDHF calculations. Using the particle-number projection method, production probabilities, total angular momenta, and excitation energies of primary reaction products are extracted from the TDHF wave function after collision. Production cross sections for secondary reaction products are evaluated employing GEMINI++. Results are compared with available experimental data and widely used grazing calculations. Results: The method is applied to describe cross sections for multinucleon transfer processes in 40Ca+124Sn (Ec .m .≃128.54 MeV ), 48Ca+124Sn (Ec .m .≃125.44 MeV ), 40Ca+208Pb (Ec .m .≃208.84 MeV ), 58Ni+208Pb (Ec .m .≃256.79 MeV ), 64Ni+238U (Ec .m .≃307.35 MeV ), and 136Xe+198Pt (Ec .m .≃644.98 MeV ) reactions at energies close to the Coulomb barrier. It is shown that the inclusion of secondary deexcitation processes, which are dominated by neutron evaporation in the present systems, substantially improves agreement with the experimental data. The magnitude of the evaporation effects is very similar to the one observed in grazing calculations. TDHF+GEMINI provides better description of the absolute value of the cross sections for channels involving transfer of more than one proton, compared to the grazing

  18. Are One-Electron Bonds Any Different from Standard Two-Electron Covalent Bonds?

    PubMed

    Sousa, David Wilian Oliveira de; Nascimento, Marco Antonio Chaer

    2017-09-19

    The nature of the chemical bond is perhaps the central subject in theoretical chemistry. Our understanding of the behavior of molecules developed amazingly in the last century, mostly with the rise of quantum mechanics (QM) and QM-based theories such as valence bond theory and molecular orbital theory. Such theories are very successful in describing molecular properties, but they are not able to explain the origin of the chemical bond. This problem was first analyzed in the 1960s by Ruedenberg, who showed that covalent bonds are the direct result of quantum interference between one-electron states. The generality of this result and its quantification were made possible through the recent development of the generalized product function energy partitioning (GPF-EP) method by our group, which allows the partitioning of the electronic density and energy into their interference and quasi-classical (noninterference) contributions. Furthermore, with GPF wave functions these effects can be analyzed separately for each bond of a molecule. This interference energy analysis has been applied to a large variety of molecules, including diatomics and polyatomics, molecules with single, double, and triple bonds, molecules with different degrees of polarity, linear or branched molecules, cyclic or acyclic molecules, conjugated molecules, and aromatics, in order to verify the role played by quantum interference. In all cases the conclusion is exactly the same: for each bond in each of the molecules considered, the main contribution to its stability comes from the interference term. Two-center one-electron (2c1e) bonds are the simplest kind of chemical bonds. Yet they are often viewed as odd or unconventional cases of bonding. Are they any different from conventional (2c2e) bonds? If so, what differences can we expect in the nature of (2c1e) bonds relative to electron-pair bonds? In this Account, we extend the GPF-EP method to describe bonds involving N electrons in M orbitals (N < M

  19. Optimal control of the electronic current density: Application to one- and two-dimensional one-electron systems

    SciTech Connect

    Kammerlander, David; Marques, Miguel A. L.; Castro, Alberto

    2011-04-15

    Quantum optimal control theory is a powerful tool for engineering quantum systems subject to external fields such as the ones created by intense lasers. The formulation relies on a suitable definition for a target functional, that translates the intended physical objective to a mathematical form. We propose the use of target functionals defined in terms of the one-particle density and its current. A strong motivation for this is the possibility of using time-dependent density-functional theory for the description of the system dynamics. We exemplify this idea by defining an objective functional that on one hand attempts a large overlap with a target density and on the other hand minimizes the current. The latter requirement leads to optimized states with increased stability, which we prove with a few examples of one- and two-dimensional one-electron systems.

  20. One-electron singular spectral features of the 1D Hubbard model at finite magnetic field

    NASA Astrophysics Data System (ADS)

    Carmelo, J. M. P.; Čadež, T.

    2017-01-01

    The momentum, electronic density, spin density, and interaction dependences of the exponents that control the (k , ω)-plane singular features of the σ = ↑ , ↓ one-electron spectral functions of the 1D Hubbard model at finite magnetic field are studied. The usual half-filling concepts of one-electron lower Hubbard band and upper Hubbard band are defined in terms of the rotated electrons associated with the model Bethe-ansatz solution for all electronic density and spin density values and the whole finite repulsion range. Such rotated electrons are the link of the non-perturbative relation between the electrons and the pseudofermions. Our results further clarify the microscopic processes through which the pseudofermion dynamical theory accounts for the one-electron matrix elements between the ground state and excited energy eigenstates.

  1. One-Electron Reduction of Penicillins in Relation to the Oxidative Stress Phenomenon

    PubMed Central

    Szabó, László; Tóth, Tünde; Takács, Erzsébet; Wojnárovits, László

    2015-01-01

    Certain bactericidal antibiotics target mitochondrial components and, due to the leakage of electrons from the electron transport chain, one-electron reduction might occur that can lead to intermediates passing the electron to suitable acceptors. This study aimed at investigating the one-electron reduction mechanism of selected penicillin derivatives using pulse radiolysis techniques. Penicillins can accommodate the electron on each of their carbonyl carbon. Ketyl radicals are thus produced, which are reducing agents with possibility to interact with suitable biomolecules. A detailed mechanism of the reduction is reported. PMID:26690427

  2. Enzymatic recycling of oxidized ascorbate in pig heart: one-electron vs two-electron pathway.

    PubMed

    Coassin, M; Tomasi, A; Vannini, V; Ursini, F

    1991-11-01

    Enzymatic systems able to reduce either dehydroascorbate or ascorbyl radical back to ascorbate by "recycling" vitamin C may contribute to lowering the nutritional requirement of it and to increase tissue antioxidant capacity. The activities of two enzymatic activities, GSH-dehydroascorbate reductase (two-electron reduction pathway) and NADH-semidehydroascorbate reductase (one-electron reduction pathway) in pig tissues, have been investigated. The activity of glutathione-dependent reduction of dehydroascorbate, although measurable, appeared negligible taking into consideration the low physiological substrate concentration. On the other hand, the one-electron reduction of ascorbyl radical resulted fast enough to slow down the consumption of the antioxidant vitamin.

  3. One-Electron Reduction of Penicillins in Relation to the Oxidative Stress Phenomenon.

    PubMed

    Szabó, László; Tóth, Tünde; Takács, Erzsébet; Wojnárovits, László

    2015-12-11

    Certain bactericidal antibiotics target mitochondrial components and, due to the leakage of electrons from the electron transport chain, one-electron reduction might occur that can lead to intermediates passing the electron to suitable acceptors. This study aimed at investigating the one-electron reduction mechanism of selected penicillin derivatives using pulse radiolysis techniques. Penicillins can accommodate the electron on each of their carbonyl carbon. Ketyl radicals are thus produced, which are reducing agents with possibility to interact with suitable biomolecules. A detailed mechanism of the reduction is reported.

  4. COMPUTATIONAL ELECTROCHEMISTRY: AQUEOUS ONE-ELECTRON OXIDATION POTENTIALS FOR SUBSTITUTED ANILINES

    EPA Science Inventory

    Semiempirical molecular orbital theory and density functional theory are used to compute one-electron oxidation potentials for aniline and a set of 21 mono- and di-substituted anilines in aqueous solution. Linear relationships between theoretical predictions and experiment are co...

  5. One-electron standard reduction potentials of nitroaromatic and cyclic nitramine explosives

    USDA-ARS?s Scientific Manuscript database

    Extensive studies have been conducted in the past decades to predict the environmental abiotic and biotic redox fate of nitroaromatic and nitramine explosives. However, surprisingly little information is available on one-electron standard reduction potentials (Eo(R-NO2/R-NO2_)). The Eo(R-NO2/R-NO2...

  6. COMPUTATIONAL ELECTROCHEMISTRY: AQUEOUS ONE-ELECTRON OXIDATION POTENTIALS FOR SUBSTITUTED ANILINES

    EPA Science Inventory

    Semiempirical molecular orbital theory and density functional theory are used to compute one-electron oxidation potentials for aniline and a set of 21 mono- and di-substituted anilines in aqueous solution. Linear relationships between theoretical predictions and experiment are co...

  7. A one-electron approximation to domain-averaged Fermi hole analysis.

    PubMed

    Cooper, David L; Ponec, Robert

    2008-03-07

    In general, full domain-averaged Fermi hole (DAFH) analysis for correlated wavefunctions requires explicit use of the correlated pair density, but such a quantity is not always readily available. We propose instead a simple one-electron approximation, which we call pseudo-DAFH or pDAFH, and which requires instead only the natural orbitals (and their occupation numbers). From comparisons of the DAFH and pDAFH modes of analysis for the bond dissociation processes in H2, N2 and LiH, as well as for the electronic structure of more complex bonding patterns, such as in CH2Li2 and Li4, we conclude that pDAFH analysis could indeed prove to be very useful when the correlated pair density is not available. Detailed comparisons are also presented of values of the shared-electron distribution index (SEDI), a proposed one-electron approximation to it (pSEDI) and a generalized Wiberg index.

  8. Effective one body description of tidal effects in inspiralling compact binaries

    SciTech Connect

    Damour, Thibault; Nagar, Alessandro

    2010-04-15

    The late part of the gravitational wave signal of binary neutron-star (or black-hole-neutron-star) inspirals can in principle yield crucial information on the nuclear equation of state via its dependence on relativistic tidal parameters. In the hope of analytically describing the gravitational wave phasing during the late inspiral (essentially up to merger) we propose an extension of the effective one body (EOB) formalism which includes tidal effects. We compare the prediction of this tidal-EOB formalism to recently computed nonconformally flat quasiequilibrium circular sequences of binary neutron-star systems. Our analysis suggests the importance of higher-order (post-Newtonian) corrections to tidal effects, even beyond the first post-Newtonian order, and their tendency to significantly increase the 'effective tidal polarizability' of neutron stars. We propose to use the EOB description up to the moment where the tidally deformed compact objects formally enter 'into contact'. We compare the EOB predictions to some recently advocated, nonresummed, post-Newtonian based ('Taylor-T4') description of the phasing of inspiralling systems. This comparison shows the strong sensitivity of the late-inspiral phasing to the choice of the analytical model. A sufficiently accurate numerical-relativity - 'calibrated' EOB model might, however, give us a reliable analytical description of the late inspiral of compact binaries (and might also help in predicting the conditions necessary for the generation of short gamma-ray bursts).

  9. One electron oxidation of 3-methylcholanthrene: A chemical model for its mechanism of carcinogenesis

    NASA Astrophysics Data System (ADS)

    Lehner, Andreas F.; Horn, Jamie; Flesher, James W.

    2017-06-01

    One electron transfer oxidation has long been proposed as a route to the ultimate electrophilic and carcinogenic metabolites of both methylated and non-methylated polycyclic aromatic hydrocarbons (PAH). The carcinogenic hydrocarbon 3-methylcholanthrene (3-MC) has a methyl-analogous function at its meso-anthracenic center in the form of a dimethylene bridge, and treatment of this compound with the one electron transfer oxidizing reagent ferric ferricyanide, FeIII(FeIII(CN)6), in mixed aqueous-organic media generated multiple oxygenated species, many of which duplicate those found in mammalian metabolism including known carcinogens 1-hydroxy-3MC and 1-keto-3MC. These results are in agreement with a Unified Theory for PAH Carcinogenicity which predicts in vivo generation of a proximate benzylic alcohol metabolite from the 3-MC procarcinogen and conjugation with a moiety such as sulfate intended for rapid urinary excretion. The sulfate instead acts as a leaving group and generates an electrophilic carbocation capable of reacting with sensitive nucleophiles such as DNA in cellular nuclei. The products of one electron transfer oxidation align well with predictions of the Unified Theory since in many cases these products provide substrates or precursors for conjugation reactions.

  10. Improving Institutional Effectiveness: Description and Application of an Implementation Model

    ERIC Educational Resources Information Center

    Sheldon, Michael R.; Golub, Andrew J.; Langevin, John R.; St. Ours, Paulette A.; Swartzlander, Barbara J.

    2008-01-01

    The higher education literature continues to highlight difficulties with efforts to implement and sustain institutional effectiveness activities. This article describes an implementation effectiveness model from the field of organizational management and applies it to the implementation of institutional effectiveness initiatives in higher…

  11. One-electron pseudopotential investigation of the RbAr and FrAr van der Waals systems

    NASA Astrophysics Data System (ADS)

    Dhiflaoui, J.; Berriche, H.

    2012-12-01

    The potential energy curves of the ground state and many excited states of RbAr and FrAr van der Waals systems have been determined using a one-electron pseudopotential approach. The pseudopotential technique is used to replace the effect of the Rb+ and Fr+ cores and the electron-Ar interaction. In addition a core-core interaction is included. This has permitted to reduce the number of active electrons of the RbAr and FrAr systems to only one electron, the valence electron. This has led to use very large basis sets for Rb, Fr and Ar atoms. In this context, the potential energy curves of the ground and many excited states are performed at the SCF level. The core-core interactions for Rb+Ar and Fr+Ar are included using the CCSD(T) accurate potentials of Hickling et al. [H. Hickling, L. Viehland, D. Shepherd, P. Soldan, E. Lee and T. Wright, Phys. Chem. Chem. Phys. 6 (2004) 4233]. In addition, the spectroscopic constants of these states are derived and compared with the available theoretical works. Such comparison for RbAr has shown a very good agreement for the ground and the first excited states. However, the FrAr system was not studied previously and its spectroscopic constants are presented here for the first time.

  12. A Newtonian Description of the Linear Stark Effect

    NASA Astrophysics Data System (ADS)

    Woodyard, James; Espinosa, James

    2010-10-01

    After the discovery of the magnetic effect on spectral lines by Zeeman, it was only natural that physicists should look for a similar effect when an electric field was applied. A nonlinear model of the hydrogen atom developed by Woldemar Voigt was investigated and predicted a second order effect that would require huge electric fields in the ten of millions of volts per centimeter. Fortunately, Johannes Stark ignored this ominous prediction by a leading theoretician and discovered a linear electric effect that would quickly be named after himself. Soon after Bohr introduced his quantum theory of the Hydrogen Atom, Schwarzschild and Epstein independently utilized Sommerfeld's extension of Bohr's theory to arrive at an empirically correct formula. We will show how our classical theory of the hydrogen atom can account for the linear Stark effect.

  13. Redox behaviour of nifuroxazide: generation of the one-electron reduction product.

    PubMed

    Squella, J A; Letelier, M E; Lindermeyer, L; Nuñez-Vergara, L J

    1996-01-05

    The electrochemical properties of nifuroxazide have been investigated in aqueous and aqueous-DMF mixed solvents. In aqueous media, a single, irreversible four-electron reduction occurs to give the hydroxylamine derivative. In mixed media, a reversible one-electron reduction to form a nitro radical anion takes place. Cyclic voltammetric studies show that the anion radical product is stable, although the nitro radical anion intermediate shows a tendency to undergo further chemical reactions. A comparison with the voltammetric behaviour of other nitrofurans such as nifurtimox, nitrofurazone and furazolidone is made. The electrochemically-obtained parameters are correlated with the in vivo studies of oxygen consumption on Trypanosoma cruzi cell suspensions.

  14. Methionine one-electron oxidation: Coherent contributions from radiolysis, IRMPD spectroscopy, DFT calculations and electrochemistry

    NASA Astrophysics Data System (ADS)

    Scuderi, Debora; Bergès, Jacqueline; de Oliveira, Pedro; Houée-Levin, Chantal

    2016-11-01

    Methionine is an essential amino acid, unfortunately prone to oxidation. The mechanism of its oxidation by •OH radicals has been studied for more than 40 years and still remains misunderstood. We have reinvestigated the oxidation of this residue in model peptides, aiming at i) improving the identification of free radicals by the use of more modern quantum chemistry methods; ii) reinvestigating the one-electron reduction potentials as a function of the position in the sequence; iii) identifying the final compounds, which were still unknown; iv) reinvestigating the intramolecular electron transfer (IET) involving this residue.

  15. On the kinetics and energetics of one-electron oxidation of 1,3,5-triazines.

    PubMed

    Azenha, M E D G; Burrows, H D; Canle, M; Coimbra, R; Fernández, M I; García, M V; Rodrigues, A E; Santaballa, J A; Steenken, S

    2003-01-07

    One-electron oxidation of 1,3,5-triazines is observed with both excited uranyl ion (*UO2(2+)) and sulfate radical anion (SO4.-) in aqueous solution, but not with Tl2+, indicating that the standard reduction potentials E degree of 1,3,5-triazine radical cations are = 2.3 +/- 0.1 V vs. NHE, consistent with theoretical calculations; this suggests that if triazines inhibit electron transfer during photosynthesis, they would need to act on the reductive part of the electron transport chain.

  16. Arsenate stabilized Cu₂O nanoparticle catalyst for one-electron transfer reversible reaction.

    PubMed

    Sahoo, Ramkrishna; Dutta, Soumen; Pradhan, Mukul; Ray, Chaiti; Roy, Anindita; Pal, Tarasankar; Pal, Anjali

    2014-05-14

    The befitting capping capabilities of AsO4(3-) provide a stable Cu2O nanocatalyst from a galvanic reaction between a Cu(II) precursor salt and As(0) nanoparticles. This stable Cu2O hydrosol appears to be a suitable catalyst for the one-electron transfer reversible redox reaction between Eosin Y and NaBH4. The progress of the reaction relates to three different kinetic stages. In the presence of the new catalyst the reversible redox reaction of Eosin Y in air shows a periodic color change providing a new crowd-pleasing demonstration, i.e. a "clock reaction".

  17. Electron-nuclear dynamics of the one-electron nonlinear polyatomic molecule H32+ in ultrashort intense laser pulses

    NASA Astrophysics Data System (ADS)

    Lefebvre, C.; Lu, H. Z.; Chelkowski, S.; Bandrauk, A. D.

    2014-02-01

    A quantum description of the one-electron triangular H32+ molecular ion, beyond the Born-Oppenheimer approximation, is used to study the full influence of the nuclear motion on the high-intensity photoionization and harmonic generation processes. A detailed analysis of electron and proton motions and their time-dependent acceleration allows for identification of the main electron recollision events as a function of time-dependent configuration of the protons. High-order-harmonic generation photons are shown to be produced by single-electron recollision in the second half of the pulse envelope, which also induces a redshift in the harmonics, due to the rapid few-femtosecond motions of protons. Perpendicular harmonics are produced, in general, with a linearly polarized laser pulse parallel to a bond of the triangular molecule, and, in particular, the harmonics in the cutoff region are elliptically polarized. When the laser-pulse polarization is parallel to a symmetry axis of the triangular molecular ion, creation and destruction of the chemical bond perpendicular to the polarization is predicted on a near-femtosecond time scale.

  18. Generalization of the Kohn-Sham system that can represent arbitrary one-electron density matrices

    DOE PAGES

    Hubertus J. J. van Dam

    2016-04-27

    Density functional theory is currently the most widely applied method in electronic structure theory. The Kohn-Sham method, based on a fictitious system of noninteracting particles, is the workhorse of the theory. The particular form of the Kohn-Sham wave function admits only idempotent one-electron density matrices whereas wave functions of correlated electrons in post-Hartree-Fock methods invariably have fractional occupation numbers. Here we show that by generalizing the orbital concept and introducing a suitable dot product as well as a probability density, a noninteracting system can be chosen that can represent the one-electron density matrix of any system, even one with fractionalmore » occupation numbers. This fictitious system ensures that the exact electron density is accessible within density functional theory. It can also serve as the basis for reduced density matrix functional theory. Moreover, to aid the analysis of the results the orbitals may be assigned energies from a mean-field Hamiltonian. This produces energy levels that are akin to Hartree-Fock orbital energies such that conventional analyses based on Koopmans' theorem are available. Lastly, this system is convenient in formalisms that depend on creation and annihilation operators as they are trivially applied to single-determinant wave functions.« less

  19. Generalization of the Kohn-Sham system that can represent arbitrary one-electron density matrices

    NASA Astrophysics Data System (ADS)

    van Dam, Hubertus J. J.

    2016-05-01

    Density functional theory is currently the most widely applied method in electronic structure theory. The Kohn-Sham method, based on a fictitious system of noninteracting particles, is the workhorse of the theory. The particular form of the Kohn-Sham wave function admits only idempotent one-electron density matrices whereas wave functions of correlated electrons in post-Hartree-Fock methods invariably have fractional occupation numbers. Here we show that by generalizing the orbital concept and introducing a suitable dot product as well as a probability density, a noninteracting system can be chosen that can represent the one-electron density matrix of any system, even one with fractional occupation numbers. This fictitious system ensures that the exact electron density is accessible within density functional theory. It can also serve as the basis for reduced density matrix functional theory. Moreover, to aid the analysis of the results the orbitals may be assigned energies from a mean-field Hamiltonian. This produces energy levels that are akin to Hartree-Fock orbital energies such that conventional analyses based on Koopmans' theorem are available. Finally, this system is convenient in formalisms that depend on creation and annihilation operators as they are trivially applied to single-determinant wave functions.

  20. QED calculations in heavy many-electron atoms and one-electron quasi-molecules

    NASA Astrophysics Data System (ADS)

    Tupitsyn, I. I.; Safronova, M. S.; Kozlov, M. G.; Porsev, S. G.; Shabaev, V. M.

    2016-05-01

    Construction of simple one-electron approach to one-loop QED operator is an important task for the relativistic quantum theory of atoms and molecules. In this work we used two modifications of the model QED potential approach to calculations of the Lamb shift in many-electron atoms and one-electron quasi-molecules. The model potential is constructed as a sum of local and nonlocal (separable) potentials. The nonlocal part of the model potential was introduced to reproduce exactly the diagonal elements and also off-diagonal elements of the one-loop ab initio QED operator. The one-particle model QED operator was introduced in the Dirac-Fock and CI+MBPT relativistic calculations of the heavy and super-heavy atoms and in the calculations of the diatomic quasi-molecules. The comparison of the data obtained in different approaches to the one-loop QED operator is presented. Model QED potential is applied to calculate Lamb shift in the U91+- U92+ dimer. The results are compared with Ref..

  1. Generalization of the Kohn-Sham system that can represent arbitrary one-electron density matrices

    SciTech Connect

    Hubertus J. J. van Dam

    2016-04-27

    Density functional theory is currently the most widely applied method in electronic structure theory. The Kohn-Sham method, based on a fictitious system of noninteracting particles, is the workhorse of the theory. The particular form of the Kohn-Sham wave function admits only idempotent one-electron density matrices whereas wave functions of correlated electrons in post-Hartree-Fock methods invariably have fractional occupation numbers. Here we show that by generalizing the orbital concept and introducing a suitable dot product as well as a probability density, a noninteracting system can be chosen that can represent the one-electron density matrix of any system, even one with fractional occupation numbers. This fictitious system ensures that the exact electron density is accessible within density functional theory. It can also serve as the basis for reduced density matrix functional theory. Moreover, to aid the analysis of the results the orbitals may be assigned energies from a mean-field Hamiltonian. This produces energy levels that are akin to Hartree-Fock orbital energies such that conventional analyses based on Koopmans' theorem are available. Lastly, this system is convenient in formalisms that depend on creation and annihilation operators as they are trivially applied to single-determinant wave functions.

  2. Pulse radiolysis of silybin: One-electron oxidation of the flavonoid at neutral pH

    NASA Astrophysics Data System (ADS)

    György, I.; Antus, S.; Földiák, G.

    One-electron oxidation of silybin, a flavonoid drug used in human therapy of liver, was investigated by pulse radiolysis at neutral pH. Phenoxyl radicals formed from the substrate by oxidising N .3 radicals were identified by comparing the transient optical absorption spectra with those obtained from model compounds. The orto-methoxy-phenolic structure (ring B) is the exclusive target for one-electron oxidation of silybin. The 5.7-dihydroxy-chromanone moiety (ring A) withstands free-radical attack at neutral pH due to the chelatic H-bond (p Ka = 10.2) existing between the 5-OH and 4-oxo groups. Hydroxyl radicals react with silybin at diffusion controlled rate ( k = 1.8 x 10 10 dm 3 mol -1 s -1). The reactivity of silybin towards free radicals at neutral pH is conform with the assumption that the physiological activity of the flavonoid is due to its chain-breaking antioxidant behaviour.

  3. Generalization of the Kohn-Sham system that can represent arbitrary one-electron density matrices

    SciTech Connect

    Hubertus J. J. van Dam

    2016-04-27

    Density functional theory is currently the most widely applied method in electronic structure theory. The Kohn-Sham method, based on a fictitious system of noninteracting particles, is the workhorse of the theory. The particular form of the Kohn-Sham wave function admits only idempotent one-electron density matrices whereas wave functions of correlated electrons in post-Hartree-Fock methods invariably have fractional occupation numbers. Here we show that by generalizing the orbital concept and introducing a suitable dot product as well as a probability density, a noninteracting system can be chosen that can represent the one-electron density matrix of any system, even one with fractional occupation numbers. This fictitious system ensures that the exact electron density is accessible within density functional theory. It can also serve as the basis for reduced density matrix functional theory. Moreover, to aid the analysis of the results the orbitals may be assigned energies from a mean-field Hamiltonian. This produces energy levels that are akin to Hartree-Fock orbital energies such that conventional analyses based on Koopmans' theorem are available. Lastly, this system is convenient in formalisms that depend on creation and annihilation operators as they are trivially applied to single-determinant wave functions.

  4. The Effect of Descriptive Norms on Pregaming Frequency: Tests of Five Moderators.

    PubMed

    Merrill, Jennifer E; Kenney, Shannon R; Carey, Kate B

    2016-07-02

    Pregaming is highly prevalent on college campuses and associated with heightened levels of intoxication and risk of alcohol consequences. However, research examining the correlates of pregaming behavior is limited. Descriptive norms (i.e., perceptions about the prevalence or frequency of a behavior) are reliable and comparatively strong predictors of general drinking behavior, with recent evidence indicating that they are also associated with pregaming. We tested the hypothesis that higher descriptive norms for pregaming frequency would be associated with personal pregaming frequency. We also tested whether this effect would be stronger in the context of several theory-based moderators: female gender, higher injunctive norms (i.e., perceptions of others' attitudes toward a particular behavior), a more positive attitude toward pregaming, a stronger sense of identification with the drinking habits of other students, and stronger social comparison tendencies. College student drinkers (N = 198, 63% female) participated in an online survey assessing frequency of pregaming, descriptive norms, and hypothesized moderators. A multiple regression model revealed that higher descriptive norms, a more positive attitude toward pregaming, and stronger peer identification were significantly associated with greater pregaming frequency among drinkers. However, no moderators of the association between descriptive norms and pregaming frequency were observed. Descriptive norms are robust predictors of pregaming behavior, for both genders and across levels of several potential moderators. Future research seeking to understand pregaming behavior should consider descriptive norms, as well as personal attitudes and identification with student peers, as targets of interventions designed to reduce pregaming.

  5. Effects of perceived descriptive norms on corrupt intention: The mediating role of moral disengagement.

    PubMed

    Zhao, Huanhuan; Zhang, Heyun; Xu, Yan

    2017-01-31

    The present study attempts to examine the effect of perceived descriptive norms on corrupt intention (e.g., bribe-taking intention) and then further explore the psychological mechanism underlying this effect. Based on social cognitive theory, we established a mediation model in which moral disengagement partially mediated the link between perceived descriptive norms and corrupt intention. In Study 1, participants (N = 690) completed a series of questionnaires, and the results demonstrated that, while perceived descriptive norms were positively associated with corrupt intention, it was partially mediated by moral disengagement. In Study 2, we conducted a priming experiment (N = 161) to test the causal relationship and psychological mechanism between perceived descriptive norms and corrupt intention. The results revealed that perceived descriptive norms triggered the propensity of individuals to morally disengage, which in turn, partially increased their corrupt intention. This study not only extends previous research by providing evidence that moral disengagement may be one of the reasons why perceived descriptive norms facilitate corrupt intention, but also suggests that reshaping normative beliefs and preventing the moral disengagement of individuals may be the effective ways to curb corrupt behaviours. © 2017 International Union of Psychological Science.

  6. Effective description of dark matter as a viscous fluid

    NASA Astrophysics Data System (ADS)

    Floerchinger, Stefan; Garny, Mathias; Tetradis, Nikolaos; Wiedemann, Urs Achim

    2016-10-01

    Treating dark matter at large scales as an effectively viscous fluid provides an improved framework for the calculation of the density and velocity power spectra compared to the standard assumption of an ideal pressureless fluid. We discuss how this framework can be made concrete through an appropriate coarse-graining procedure. We also review results that demonstrate that it improves the convergence of cosmological perturbation theory.

  7. A Focker-Planck description of the spin Seebeck effect

    NASA Astrophysics Data System (ADS)

    Reyes, Guillermo; Reyes, Juan Adrian

    Thermally driven spin-wave spin current in a ferromagnetic material FM and the resulting electric signal in a metal probe placed on the FM are theoretically investigated by considering a thermally fluctuating spin at the interface of a FM-metal junction. We develop an analytical formulation to establish a Focker Plank equation for the probability distribution as a function of magnetization components of the material, for calculating the spin Seebeck signal detected by the metal probe, which converts spin current to charge current by the inverse spin Hall effect. The spin current is induced in the metal probe via an exchange interaction when the metal senses the temperature gradient.

  8. An effective Lagrangian description of supernova-core bounce

    NASA Astrophysics Data System (ADS)

    Rodrigues, H.; Deavila, V.; Duarte, S. J. B.; Kodama, T.

    1990-08-01

    The global dynamical aspects of a supernova event are studied in terms of an effective Lagrangian formulation. The equation of motion derived from this Lagrangian is solved numerically for different supernova core masses. An equation of state for cold matter is introduced by means of an adiabatic index parametrization which is a smooth function of the matter density. The energy transfer from the inner to the outer core is estimated in the context of the hydrodynamic bounce mechanism. It is found that only a very restricted mass distribution to pre-supernova core configuration generate a strong enough shock wave leading to a prompt bounce ejection.

  9. Effective description of higher-order scalar-tensor theories

    NASA Astrophysics Data System (ADS)

    Langlois, David; Mancarella, Michele; Noui, Karim; Vernizzi, Filippo

    2017-05-01

    Most existing theories of dark energy and/or modified gravity, involving a scalar degree of freedom, can be conveniently described within the framework of the Effective Theory of Dark Energy, based on the unitary gauge where the scalar field is uniform. We extend this effective approach by allowing the Lagrangian in unitary gauge to depend on the time derivative of the lapse function. Although this dependence generically signals the presence of an extra scalar degree of freedom, theories that contain only one propagating scalar degree of freedom, in addition to the usual tensor modes, can be constructed by requiring the initial Lagrangian to be degenerate. Starting from a general quadratic action, we derive the dispersion relations for the linear perturbations around Minkowski and a cosmological background. Our analysis directly applies to the recently introduced Degenerate Higher-Order Scalar-Tensor (DHOST) theories. For these theories, we find that one cannot recover a Poisson-like equation in the static linear regime except for the subclass that includes the Horndeski and so-called "beyond Horndeski" theories. We also discuss Lorentz-breaking models inspired by Horava gravity.

  10. Effective Field Theory Description of Two-Body Resonance States

    NASA Astrophysics Data System (ADS)

    Balalhabashi, Jaber

    2017-01-01

    The quantum-mechanical scattering of two particles around a resonance state appears in many areas of physics, for example in cold atoms near narrow, low-lying Feshbach resonances. We construct) an EFT that describes such scattering with contact, derivative interactions. We demonstrate that a careful choice of leading- and next-to-leading-order terms in an effective Lagrangian gives rise to a systematic expansion of the T matrix around the resonance, with controlled error estimates. We compare phase shifts and pole positions with those of a toy model. We are extending our EFT to include Coulomb interactions with the goal of describing nuclear resonances, such as those appearing in the scattering of alpha particles. This material is based upon work supported in part by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-FG02-04ER41338.

  11. Description and effects of sequential behavior practice in teacher education.

    PubMed

    Sharpe, T; Lounsbery, M; Bahls, V

    1997-09-01

    This study examined the effects of a sequential behavior feedback protocol on the practice-teaching experiences of undergraduate teacher trainees. The performance competencies of teacher trainees were analyzed using an alternative opportunities for appropriate action measure. Data support the added utility of sequential (Sharpe, 1997a, 1997b) behavior analysis information in systematic observation approaches to teacher education. One field-based undergraduate practicum using sequential behavior (i.e., field systems analysis) principles was monitored. Summarized are the key elements of the (a) classroom instruction provided as a precursor to the practice teaching experience, (b) practice teaching experience, and (c) field systems observation tool used for evaluation and feedback, including multiple-baseline data (N = 4) to support this approach to teacher education. Results point to (a) the strong relationship between sequential behavior feedback and the positive change in four preservice teachers' day-to-day teaching practices in challenging situational contexts, and (b) the relationship between changes in teacher practices and positive changes in the behavioral practices of gymnasium pupils. Sequential behavior feedback was also socially validated by the undergraduate participants and Professional Development School teacher supervisors in the study.

  12. The rotation effect on tokamak stability in the gyrokinetic description

    NASA Astrophysics Data System (ADS)

    Zheng, L.-J.; Tessarotto, M.

    1996-11-01

    The combined eigenvalue and initial value problems for both ion temperature gradient (ITG) and ballooning modes are solved analytically, with full gyrokinetic and toroidal effects taken into account. The results show that the sonic rotation can be harmful for both ITG and ballooning stabilities, while subsonic rotation plays always a stabilizing role. The flow shear damping on the ballooning modes is found to be much weaker than that on the ITG ones. This suggests that the ballooning instabilities are more likely to develop than the ITG modes in the rotating plasmas. The existence of the flow shear leads the time evolution of the fluctuation signals to become the type containing two timescales --- fast oscillating (with either fast or slow growing) signals with their amplitudes modulated by the slow oscillating and damping envelops, looking as if fish-bone like fluctuations. The comparison with the experimental observations are also discussed, in addressing the issues that which type of modes: the electrostatic drift or the MHD ones is likely to be responsible for the anomalous transport in tokamaks, and how to suppress them based on the current analyses.

  13. One-electron oxidation in irradiated carbon tetrachloride solutions of ZnTPP, TMPD, and phenols. [Pulsed irradiation

    SciTech Connect

    Grodkowski, J.; Neta, P.

    1984-03-15

    One-electron oxidation of phenol, p-methoxphenol, N,N,N',N'-tetramethyl-p-phenylenediamine, chlorpromazine, and zinc tetraphenolporphyrin (ZnTPP) was studied by pulse radiolysis in carbon tetrachloride solutions. Phenols form phenoxyl radicals and the other compounds form cation radicals with yields strongly dependent on solute concentration. The highest yield in deoxygenated solutions approached G = 4. In the presence of oxygen an additional oxidation step is observed owing to CCl/sub 3/O/sub 2/ radicals and the overall oxidation yield approached G = 8. ZnTPP was found to be oxidized to the cation radical without any side effects, unlike oxidation in 1,2-dichloroethane which was accompanied by demetallation owing to HCl production.

  14. Frequency-dependent polarizabilities and shielding factors for confined one-electron systems

    NASA Astrophysics Data System (ADS)

    Montgomery, H. E., Jr.; Pupyshev, Vladimir I.

    2017-01-01

    Frequency-dependent dipole polarizabilities and shielding factors are calculated for the ground state of spherically symmetric screened one-electron systems embedded in an impenetrable spherical cavity. Coulomb, Yukawa, Hulthén and exponential cosine-screened Coulomb potentials are considered. In contrast to free systems, Dirichlet boundary conditions introduce a contribution to the shielding factor that results from an integral over the surface of the confining boundary. This is a fundamental difference between free and confined systems and results in unexpected modifications to some of the classic relations for free systems. The methods derived also give a simple expression for the polarizability of the confined harmonic oscillator as an example of extending the methods of this work to potentials beyond the four studied.

  15. Excess electrons in methanol clusters: Beyond the one-electron picture

    NASA Astrophysics Data System (ADS)

    Pohl, Gábor; Mones, Letif; Turi, László

    2016-10-01

    We performed a series of comparative quantum chemical calculations on various size negatively charged methanol clusters, ("separators=" CH 3 OH ) n - . The clusters are examined in their optimized geometries (n = 2-4), and in geometries taken from mixed quantum-classical molecular dynamics simulations at finite temperature (n = 2-128). These latter structures model potential electron binding sites in methanol clusters and in bulk methanol. In particular, we compute the vertical detachment energy (VDE) of an excess electron from increasing size methanol cluster anions using quantum chemical computations at various levels of theory including a one-electron pseudopotential model, several density functional theory (DFT) based methods, MP2 and coupled-cluster CCSD(T) calculations. The results suggest that at least four methanol molecules are needed to bind an excess electron on a hydrogen bonded methanol chain in a dipole bound state. Larger methanol clusters are able to form stronger interactions with an excess electron. The two simulated excess electron binding motifs in methanol clusters, interior and surface states, correlate well with distinct, experimentally found VDE tendencies with size. Interior states in a solvent cavity are stabilized significantly stronger than electron states on cluster surfaces. Although we find that all the examined quantum chemistry methods more or less overestimate the strength of the experimental excess electron stabilization, MP2, LC-BLYP, and BHandHLYP methods with diffuse basis sets provide a significantly better estimate of the VDE than traditional DFT methods (BLYP, B3LYP, X3LYP, PBE0). A comparison to the better performing many electron methods indicates that the examined one-electron pseudopotential can be reasonably used in simulations for systems of larger size.

  16. Excess electrons in methanol clusters: Beyond the one-electron picture.

    PubMed

    Pohl, Gábor; Mones, Letif; Turi, László

    2016-10-28

    We performed a series of comparative quantum chemical calculations on various size negatively charged methanol clusters, CH3OHn(-). The clusters are examined in their optimized geometries (n = 2-4), and in geometries taken from mixed quantum-classical molecular dynamics simulations at finite temperature (n = 2-128). These latter structures model potential electron binding sites in methanol clusters and in bulk methanol. In particular, we compute the vertical detachment energy (VDE) of an excess electron from increasing size methanol cluster anions using quantum chemical computations at various levels of theory including a one-electron pseudopotential model, several density functional theory (DFT) based methods, MP2 and coupled-cluster CCSD(T) calculations. The results suggest that at least four methanol molecules are needed to bind an excess electron on a hydrogen bonded methanol chain in a dipole bound state. Larger methanol clusters are able to form stronger interactions with an excess electron. The two simulated excess electron binding motifs in methanol clusters, interior and surface states, correlate well with distinct, experimentally found VDE tendencies with size. Interior states in a solvent cavity are stabilized significantly stronger than electron states on cluster surfaces. Although we find that all the examined quantum chemistry methods more or less overestimate the strength of the experimental excess electron stabilization, MP2, LC-BLYP, and BHandHLYP methods with diffuse basis sets provide a significantly better estimate of the VDE than traditional DFT methods (BLYP, B3LYP, X3LYP, PBE0). A comparison to the better performing many electron methods indicates that the examined one-electron pseudopotential can be reasonably used in simulations for systems of larger size.

  17. The Effect of Cooperative Integrated Reading and Composition Technique on Students' Reading Descriptive Text Achievement

    ERIC Educational Resources Information Center

    Zainuddin

    2015-01-01

    This study was aimed at finding out the effectiveness of applying Cooperative Integrated Reading and Composition (CIRC) Technique on Students' Reading Descriptive Text Achievement. In other words, the objective of this study was to find out if there was a significant effect of applying Cooperative Integrated Reading and Composition (CIRC)…

  18. Teacher Effectiveness, Mobility, and Attrition in Florida: A Descriptive Analysis. Research Brief

    ERIC Educational Resources Information Center

    National Center on Performance Incentives, 2008

    2008-01-01

    While there has been substantial research studying the factors that influence teachers' career decisions, there is far less literature on the relationship between teacher effectiveness, mobility, and attrition. In the paper "Teacher Effectiveness, Mobility, and Attrition in Florida: A Descriptive Analysis," Martin West and Matthew…

  19. Role descriptions induce gender mismatch effects in eye movements during reading.

    PubMed

    Reali, Chiara; Esaulova, Yulia; Öttl, Anton; von Stockhausen, Lisa

    2015-01-01

    The present eye-tracking study investigates the effect of gender typicality on the resolution of anaphoric personal pronouns in English. Participants read descriptions of a person performing a typically male, typically female or gender-neutral occupational activity. The description was followed by an anaphoric reference (he or she) which revealed the referent's gender. The first experiment presented roles which were highly typical for men (e.g., blacksmith) or for women (e.g., beautician), the second experiment presented role descriptions with a moderate degree of gender typicality (e.g., psychologist, lawyer). Results revealed a gender mismatch effect in early and late measures in the first experiment and in early stages in the second experiment. Moreover, eye-movement data for highly typical roles correlated with explicit typicality ratings. The results are discussed from a cross-linguistic perspective, comparing natural gender languages and grammatical gender languages. An interpretation of the cognitive representation of typicality beliefs is proposed.

  20. Role descriptions induce gender mismatch effects in eye movements during reading

    PubMed Central

    Reali, Chiara; Esaulova, Yulia; Öttl, Anton; von Stockhausen, Lisa

    2015-01-01

    The present eye-tracking study investigates the effect of gender typicality on the resolution of anaphoric personal pronouns in English. Participants read descriptions of a person performing a typically male, typically female or gender-neutral occupational activity. The description was followed by an anaphoric reference (he or she) which revealed the referent's gender. The first experiment presented roles which were highly typical for men (e.g., blacksmith) or for women (e.g., beautician), the second experiment presented role descriptions with a moderate degree of gender typicality (e.g., psychologist, lawyer). Results revealed a gender mismatch effect in early and late measures in the first experiment and in early stages in the second experiment. Moreover, eye-movement data for highly typical roles correlated with explicit typicality ratings. The results are discussed from a cross-linguistic perspective, comparing natural gender languages and grammatical gender languages. An interpretation of the cognitive representation of typicality beliefs is proposed. PMID:26579003

  1. The Effect of Descriptive Norms on Pregaming Frequency: Tests of Five Moderators

    PubMed Central

    Merrill, Jennifer E.; Kenney, Shannon R.; Carey, Kate B.

    2016-01-01

    Background Pregaming is highly prevalent on college campuses and associated with heightened levels of intoxication and risk of alcohol consequences. However, research examining the correlates of pregaming behavior is limited. Descriptive norms (i.e., perceptions about the prevalence or frequency of a behavior) are reliable and comparatively strong predictors of general drinking behavior, with recent evidence indicating that they are also associated with pregaming. Objectives We tested the hypothesis that higher descriptive norms for pregaming frequency would be associated with personal pregaming frequency. We also tested whether this effect would be stronger in the context of several theory-based moderators: female gender, higher injunctive norms (i.e., perceptions of others' attitudes toward a particular behavior), a more positive attitude toward pregaming, a stronger sense of identification with the drinking habits of other students, and stronger social comparison tendencies. Methods College student drinkers (N=198, 63% female) participated in an online survey assessing frequency of pregaming, descriptive norms, and hypothesized moderators. Results A multiple regression model revealed that higher descriptive norms, a more positive attitude toward pregaming, and stronger peer identification were significantly associated with greater pregaming frequency among drinkers. However, no moderators of the association between descriptive norms and pregaming frequency were observed. Conclusions/Importance Descriptive norms are robust predictors of pregaming behavior, for both genders and across levels of several potential moderators. Future research seeking to understand pregaming behavior should consider descriptive norms, as well as personal attitudes and identification with student peers, as targets of interventions designed to reduce pregaming. PMID:27070494

  2. Predicting Reduction Rates of Energetic Nitroaromatic Compounds Using Calculated One-Electron Reduction Potentials

    DOE PAGES

    Salter-Blanc, Alexandra; Bylaska, Eric J.; Johnston, Hayley; ...

    2015-02-11

    The evaluation of new energetic nitroaromatic compounds (NACs) for use in green munitions formulations requires models that can predict their environmental fate. The susceptibility of energetic NACs to nitro reduction might be predicted from correlations between rate constants (k) for this reaction and one-electron reduction potentials (E1NAC) / 0.059 V, but the mechanistic implications of such correlations are inconsistent with evidence from other methods. To address this inconsistency, we have reevaluated existing kinetic data using a (non-linear) free-energy relationship (FER) based on the Marcus theory of outer-sphere electron transfer. For most reductants, the results are inconsistent with rate limitation bymore » an initial, outer-sphere electron transfer, suggesting that the strong correlation between k and E1NAC is justified only as an empirical model. This empirical correlation was used to calibrate a new quantitative structure-activity relationship (QSAR) using previously reported values of k for non-energetic NAC reduction by Fe(II) porphyrin and newly reported values of E1NAC determined using density functional theory at the B3LYP/6-311++G(2d,2p) level with the COSMO solvation model. The QSAR was then validated for energetic NACs using newly measured kinetic data for 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), and 2,4-dinitroanisole (DNAN). The data show close agreement with the QSAR, supporting its applicability to energetic NACs.« less

  3. Predicting Reduction Rates of Energetic Nitroaromatic Compounds Using Calculated One-Electron Reduction Potentials

    SciTech Connect

    Salter-Blanc, Alexandra; Bylaska, Eric J.; Johnston, Hayley; Tratnyek, Paul G.

    2015-02-11

    The evaluation of new energetic nitroaromatic compounds (NACs) for use in green munitions formulations requires models that can predict their environmental fate. The susceptibility of energetic NACs to nitro reduction might be predicted from correlations between rate constants (k) for this reaction and one-electron reduction potentials (E1NAC) / 0.059 V, but the mechanistic implications of such correlations are inconsistent with evidence from other methods. To address this inconsistency, we have reevaluated existing kinetic data using a (non-linear) free-energy relationship (FER) based on the Marcus theory of outer-sphere electron transfer. For most reductants, the results are inconsistent with rate limitation by an initial, outer-sphere electron transfer, suggesting that the strong correlation between k and E1NAC is justified only as an empirical model. This empirical correlation was used to calibrate a new quantitative structure-activity relationship (QSAR) using previously reported values of k for non-energetic NAC reduction by Fe(II) porphyrin and newly reported values of E1NAC determined using density functional theory at the B3LYP/6-311++G(2d,2p) level with the COSMO solvation model. The QSAR was then validated for energetic NACs using newly measured kinetic data for 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), and 2,4-dinitroanisole (DNAN). The data show close agreement with the QSAR, supporting its applicability to energetic NACs.

  4. Monitoring one-electron photo-oxidation of guanine in DNA crystals using ultrafast infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Hall, James P.; Poynton, Fergus E.; Keane, Páraic M.; Gurung, Sarah P.; Brazier, John A.; Cardin, David J.; Winter, Graeme; Gunnlaugsson, Thorfinnur; Sazanovich, Igor V.; Towrie, Michael; Cardin, Christine J.; Kelly, John M.; Quinn, Susan J.

    2015-12-01

    To understand the molecular origins of diseases caused by ultraviolet and visible light, and also to develop photodynamic therapy, it is important to resolve the mechanism of photoinduced DNA damage. Damage to DNA bound to a photosensitizer molecule frequently proceeds by one-electron photo-oxidation of guanine, but the precise dynamics of this process are sensitive to the location and the orientation of the photosensitizer, which are very difficult to define in solution. To overcome this, ultrafast time-resolved infrared (TRIR) spectroscopy was performed on photoexcited ruthenium polypyridyl-DNA crystals, the atomic structure of which was determined by X-ray crystallography. By combining the X-ray and TRIR data we are able to define both the geometry of the reaction site and the rates of individual steps in a reversible photoinduced electron-transfer process. This allows us to propose an individual guanine as the reaction site and, intriguingly, reveals that the dynamics in the crystal state are quite similar to those observed in the solvent medium.

  5. One-electron reduction of 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin: a pulse radiolysis study.

    PubMed

    Goldstein, Sara

    2011-08-18

    Geldanamycin, a benzoquinone ansamycin antibiotic, is a natural product inhibitor of Hsp90 with potent and broad anticancer properties but with unacceptable levels of hepatotoxicity. Consequently, numerous structural analogs, which differ only in their 17-substituent, have been synthesized including the water-soluble and less toxic 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG, Alvespimycin). It has been suggested that the different hepatotoxicity reflects the redox active properties of the quinone moiety. The present pulse radiolysis study was aimed at studying the one-electron reduction of 17-DMAG. The UV-visible spectrum of the semiquinone radical, its pK(a), and the second-order rate constants for the reactions of 17-DMAG with CO(2)(•-) and (CH(3))(2)C(•)OH have been obtained. The reduction potential of 17-DMAG has been determined to be -194 ± 6 mV (vs NHE) using oxygen, 1,4-naphthoquinone, and menadione as electron acceptors. This reduction potential is lower than that of O(2) demonstrating that thermodynamically the semiquinone radical can reduce O(2) to superoxide, particularly since the concentration of O(2) is expected to exceed that of the drug in cells and tissues. © 2011 American Chemical Society

  6. The Effect of Progressive Sentence Development Activities on 5th Graders' Description Skills

    ERIC Educational Resources Information Center

    Hamzadayi, Ergun

    2015-01-01

    The aim of this study was to examine the effect of progressive sentence development activities on 5th graders' description skills. The study was conducted based on the pretest-posttest quasi-experimental model with a control group. A total of 58 students participated in the study; 29 in the control group, and 29 in the experimental group. The…

  7. The Effect of Progressive Sentence Development Activities on 5th Graders' Description Skills

    ERIC Educational Resources Information Center

    Hamzadayi, Ergun

    2015-01-01

    The aim of this study was to examine the effect of progressive sentence development activities on 5th graders' description skills. The study was conducted based on the pretest-posttest quasi-experimental model with a control group. A total of 58 students participated in the study; 29 in the control group, and 29 in the experimental group. The…

  8. Effects of a Training Package to Improve the Accuracy of Descriptive Analysis Data Recording

    ERIC Educational Resources Information Center

    Mayer, Kimberly L.; DiGennaro Reed, Florence D.

    2013-01-01

    Functional behavior assessment is an important precursor to developing interventions to address a problem behavior. Descriptive analysis, a type of functional behavior assessment, is effective in informing intervention design only if the gathered data accurately capture relevant events and behaviors. We investigated a training procedure to improve…

  9. Enhancing the Effectiveness of Description with Innovative Tools--The Example of MidosaXML, Germany

    ERIC Educational Resources Information Center

    Menne-Haritz, Angelika

    2005-01-01

    Online description using new Internet technologies, especially XML, is an interesting way to enhance the effectiveness and productivity of archival processing. Users and archivists benefit from the developments, making the achievement of their aims easier. The provenance-based structured presentation of finding aids can be supported with many new…

  10. Effects of a Training Package to Improve the Accuracy of Descriptive Analysis Data Recording

    ERIC Educational Resources Information Center

    Mayer, Kimberly L.; DiGennaro Reed, Florence D.

    2013-01-01

    Functional behavior assessment is an important precursor to developing interventions to address a problem behavior. Descriptive analysis, a type of functional behavior assessment, is effective in informing intervention design only if the gathered data accurately capture relevant events and behaviors. We investigated a training procedure to improve…

  11. Simultaneous evaluation of one-electron reducing systems and radical reactions in cells by nitroxyl biradical as probe.

    PubMed

    Araki, Yoko; Koshiishi, Ichiro

    2016-07-01

    In the present study, a novel probe for the simultaneous evaluation of one-electron reducing systems (electron transport chain) and one-electron oxidizing systems (free radical reactions) in cells by electron chemical detection was developed. Six-membered cyclic nitroxyl radicals (2,2,6,6-tetramethylpiperidine-1-oxyl; TEMPO series) are sensitive to one-electron redox systems, generating the hydroxylamine form [TEMPO(H)] via one-electron reduction, and the secondary amine form [TEMPO(N)] via one-electron oxidation in the presence of thiols. In contrast, the sensitivities of five-membered cyclic nitroxyl radicals (2,2,5,5-tetramethylpyrrolidine-1-oxyl; PROXYL series) to the one-electron redox systems are comparatively low. The electron chemical detector can detect 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), TEMPO(H) and PROXYL but not TEMPO(N). Therefore, nitroxyl biradical, TEMPO-PROXYL, as a probe for the evaluation of one-electron redox systems was employed. TEMPO-PROXYL was synthesized by the conjunction of 4-amino-TEMPO with 3-carboxyl-PROXYL via the conventional dicyclohexyl carbodiimide reaction. TEMPO-PROXYL, TEMPO(H)-PROXYL and TEMPO(N)-PROXYL were simultaneously quantified by HPLC with Coularray detection. Calibration curves for the quantification of TEMPO-PROXYL, TEMPO(H)-PROXYL and TEMPO(N)-PROXYL were linear in the range from 80 nm to 80 μm, and the lowest quantification limit of each molecule was estimated to be <80 nm. The relative standard deviations at 0.8 and 80 μm were within 10% (n = 5). Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Theoretical description of magnetocaloric effect in the shape memory alloy exhibiting metamagnetic behavior

    SciTech Connect

    L'vov, Victor A.; Kosogor, Anna; Barandiaran, Jose M.

    2016-01-07

    A simple thermodynamic theory is proposed for the quantitative description of giant magnetocaloric effect observed in metamagnetic shape memory alloys. Both the conventional magnetocaloric effect at the Curie temperature and the inverse magnetocaloric effect at the transition from the ferromagnetic austenite to a weakly magnetic martensite are considered. These effects are evaluated from the Landau-type free energy expression involving exchange interactions in a system of a two magnetic sublattices. The findings of the thermodynamic theory agree with first-principles calculations and experimental results from Ni-Mn-In-Co and Ni-Mn-Sn alloys, respectively.

  13. π to σ Radical Tautomerization in One-Electron Oxidized 1-Methylcytosine and its Analogs

    PubMed Central

    Adhikary, Amitava; Kumar, Anil; Bishop, Casandra T.; Wiegand, Tyler J.; Hindi, Ragda M.; Adhikary, Ananya; Sevilla, Michael D.

    2015-01-01

    In this work iminyl σ-radical formation in several one-electron oxidized cytosine analogs including 1-MeC, cidofovir, 2′-deoxycytidine (dCyd), and 2′-deoxycytidine 5′-monophosphate (5′-dCMP) were investigated in homogeneous aqueous (D2O or H2O) glassy solutions at low temperatures employing electron spin resonance (ESR) spectroscopy. Employing density functional theory (DFT) (DFT/B3LYP/6-31G* method), the calculated hyperfine coupling constant (HFCC) values of iminyl σ-radical agree quite well with the experimentally observed ones thus confirming its assignment. ESR and DFT studies show that the cytosine-iminyl σ-radical is a tautomer of the deprotonated cytosine π-cation radical (cytosine π-aminyl radical, C(N4-H)•). Employing 1-MeC samples at various pHs ranging ca. 8 to ca. 11, ESR studies show that the tautomeric equilibrium between C(N4-H)• and the iminyl σ-radical at low temperature is too slow to be established without added base. ESR and DFT studies agree that in the iminyl-σ radical, the unpaired spin is localized to the exocyclic nitrogen (N4) in an in-plane pure p-orbital. This gives rise to an anisotropic nitrogen hyperfine coupling (Azz = 40 G) from N4 and a near isotropic β-nitrogen coupling of 9.7 G from the cytosine ring nitrogen at N3. Iminyl σ-radical should exist in its N3-protonated form as the N3-protonated iminyl σ-radical is stabilized in solution by over 30 kcal/mol (ΔG= −32 kcal/mol) over its conjugate base, the N3-deprotonated form. This is the first observation of an isotropic β-hyperfine ring nitrogen coupling in an N-centered DNA-radical. Our theoretical calculations predict that the cytosine iminyl σ-radical can be formed in dsDNA by a radiation-induced ionization–deprotonation process that is only 10 kcal/mol above the lowest energy path. PMID:26237072

  14. One-electron oxidation of ruthenocene: reactions of the ruthenocenium ion in gentle electrolyte media.

    PubMed

    Swarts, Jannie C; Nafady, Ayman; Roudebush, John H; Trupia, Sabrina; Geiger, William E

    2009-03-02

    The electrochemical oxidation of ruthenocene, RuCp(2) (Cp = eta(5)-C(5)H(5)), 1, has been studied in dichloromethane using a supporting electrolyte containing either the [B(C(6)F(5))(4)](-) (TFAB) or the [B(C(6)H(3)(CF(3))(2))(4)](-) (BArF(24)) counteranion. A quasi-Nernstian process was observed in both cases, with E(1/2) values of 0.41 and 0.57 V vs FeCp(2) in the respective electrolyte media. The ruthenocenium ion 1(+) equilibrates with a metal-metal bonded dimer [Ru(2)Cp(4)](2+), 2(2+), that is increasingly preferred at low temperatures. Dimerization equilibrium constants determined by digital simulation of cyclic voltammetry (CV) curves were in the range of 10(2)-10(4) M(-1) at temperatures of 256 to 298 K. Near room temperature, and particularly when BArF(24) is the counteranion, the dinuclear species [Ru(2)Cp(2)(sigma:eta(5)-C(5)H(4))(2)] (2+), 3(2+), in which each metal is sigma-bonded to a cyclopentadienyl ring, was the preferred electrolytic oxidation product. Cathodic reduction of 3(2+) regenerated ruthenocene. The two dinuclear products, 2(2+) and 3(2+), were characterized by (1)H NMR spectroscopy on anodically electrolyzed solutions of 1 at low temperatures in CD(2)Cl(2)/[NBu(4)][BArF(24)]. The variable temperature NMR behavior of these solutions showed that 3(2+) and 2(2+) take part in a thermal equilibrium, the latter being dominant at the lowest temperatures. Ruthenocene hydride, [1-H](+), was also identified as being present in the electrolysis solutions. The oxidation of ruthenocene is shown to be an inherent one-electron process, giving a ruthenocenium ion which is highly susceptible to reactions that allow it to regain an 18-electron configuration. In a dry non-donor solvent, and in the absence of nucleophiles, this electronic configuration is attained by self-reactions involving formation of Ru-Ru or Ru-C bonds. The present data offer a mechanistic explanation for the previously described results on the chemical oxidation of osmocene (Droege, M

  15. Accurate calculation of absolute one-electron redox potentials of some para-quinone derivatives in acetonitrile.

    PubMed

    Namazian, Mansoor; Coote, Michelle L

    2007-08-02

    Standard ab initio molecular orbital theory and density functional theory calculations have been used to calculate absolute one-electron reduction potentials of several para-quinones in acetonitrile. The high-level composite method of G3(MP2)-RAD is used for the gas-phase calculations and a continuum model of solvation, CPCM, has been employed to calculate solvation energies. To compare the theoretical reduction potentials with experiment, the reduction potentials relative to a standard calomel electrode (SCE) have also been calculated and compared to experimental values. The average error of the calculated reduction potentials using the proposed method is 0.07 V without any additional approximation. An ONIOM method in which the core is studied at G3(MP2)-RAD and the substituent effect of the rest of the molecule is studied at R(O)MP2/6-311+G(3df,2p) provides an accurate low-cost alternative to G3(MP2)-RAD for larger molecules.

  16. Electrochemical one-electron oxidation of low-generation polyamidoamine-type dendrimers with a 1,4-phenylenediamine core.

    PubMed

    Hammerich, Ole; Hansen, Thomas; Thorvildsen, Asbjørn; Christensen, Jørn B

    2009-08-03

    A series of polyamidoamine (PAMAM)-type dendrimers with a 1,4-phenylenediamine (PD) core is prepared from PD by procedures including Michael addition of methyl acrylate followed by aminolysis with 1,2-ethanediamine. Their one-electron oxidation potentials are determined by differential pulse voltammetry (DPV) in methanol, acetonitrile, dichloromethane, and dimethyl sulfoxide. The dendrimers are more difficult to oxidize than N,N,N',N'-tetramethyl-p-phenylenediamine (TMePD). The oxidation potentials decrease with increasing dendrimer generation up to G0.5, after which the potential is essentially constant up to G2.0. The structures of both the neutral species and the radical cations are studied by DFT calculations at the B3LYP/6-31G(d,p) level of theory, which include a series of simple PDs for comparison. The data show that the structural arrangement close to the PD core is similar to that of N,N,N',N'-tetra-n-alkyl-p-phenylenediamines, including a planar arrangement of the atoms linked to the two PD nitrogen atoms. Thus, the effect of chain size on the oxidation potential appears to be caused primarily by a simple electronic effect. The calculations indicate considerable reorientation of the dendrimer side chains on oxidation, presumably caused by interactions between the positive charge centered at the core and the neighboring ester or amide dipoles. The relative ease of oxidation of TMePD and the lowest members of the series of the dendrimers can be reproduced theoretically only when solvation was included in the calculations. The DPV peak heights vary approximately as predicted from the Stokes-Einstein-Sutherland equation, but the variation of the relative effective radii with the size of the dendrimer is much larger than predicted from the radii obtained by the DFT calculations, that is, the dendrimers exist in solution mainly as aggregates.

  17. Animacy effects on the production of object-dislocated descriptions by Catalan-speaking children.

    PubMed

    Prat-Sala, M; Shillcock, R; Sorace, A

    2000-02-01

    This paper presents an experiment that examined two related questions. First, it examined the effects of animacy on the production of different syntactic structures and word orders by Catalan-speaking children. Secondly, it explored the relationship between age and the production of different syntactic structures by these children. The results of a picture description experiment run with eighty Catalan-speaking children aged 4;11 to 11;11 show that participants tended to produce more object-dislocated descriptions when the patient was animate than when the patient was inanimate. The results also show that while the dislocation of object clauses is a construction already consolidated at 5;0, the passive structure is a construction still not fully acquired at 11;0. A comparison between the results obtained in the present experiment with existing results from similar experiments with English-speaking children shows that there is a cross-language difference in the age at which children start producing passive clauses. We argue that frequency of exposure to a particular syntactic structure is an important factor that contributes to the acquisition of that syntactic structure. We also suggest that the effects of animacy on the production of object-dislocated descriptions can be explained by means of conceptual and lexical accessibility.

  18. Nonlinear, driven-dissipative hydrodynamics and effective chiral description of an exciton-polariton superfluid

    NASA Astrophysics Data System (ADS)

    Kulkarni, Manas; Kolmakov, German

    2015-03-01

    Given recent remarkable experimental success on capturing hydrodynamic features of exciton-polariton condensates in optical microcavities and their potential implications for quantum and optical computing and information technologies, we present an effective chiral description for such systems. This description captures the fingerprints of hydrodynamics, namely, nonlinearity, dispersion and dissipation in the exciton-polariton system. The resulting chiral equation for the condensate perturbation wave dynamics is found to be of Burgers-type thereby providing a more transparent understanding of the complicated underlying coupled exciton-photon dynamics. By using analytical calculations and numerical simulations, we describe the phenomenon of polariton shock waves, solitons and defects in such systems. Our mapping is expected to have broad implications for other polariton and photon systems including dipolar exciton and magnon condensates. This mapping can further help one in engineering a delicate balance between the pump and damping to produce stable optical signals propagating in polariton circuits.

  19. Effective chiral description of an exciton-polariton superfluid in one and two dimensions

    NASA Astrophysics Data System (ADS)

    Kulkarni, Manas; Kolmakov, German

    There has been remarkable experiments recently on capturing hydrodynamic features of exciton-polariton condensates in optical microcavities which have potential implications for quantum and optical computing and information technologies. We present an effective chiral description for such one and two dimensional systems. This description captures the fingerprints of hydrodynamics, namely, nonlinearity, dispersion and dissipation. The resulting chiral equation for the condensate perturbation wave dynamics is found to be of the generalized-KdV-type. We describe the phenomenon of polariton shock waves, solitons and defects in such systems. Our mapping is expected to have broad implications for other systems and can further help one in engineering a delicate balance between the pump and damping to produce stable optical signals propagating in polariton circuits.

  20. Description of second-order effects within the framework of endochronic inelasticity for large deformations

    NASA Astrophysics Data System (ADS)

    Kadashevich, Yu. I.; Pomytkin, S. P.

    2010-12-01

    The history of origination and development of the endochronic approach is briefly described. The Novozhilov-Kadashevich version of the flow theory is used to write the constitutive relations of endochronic type and to present a method for their generalization to the domain of large deformations and rotations. Several examples of qualitative description of inelastic second-order effects are demonstrated. It is also noted that, within the framework of geometrically linear theories of phenomenological-type inelasticity, such effects cannot be explained theoretically from unified positions.

  1. Oxidatively generated base damage to cellular DNA by hydroxyl radical and one-electron oxidants: similarities and differences.

    PubMed

    Cadet, Jean; Wagner, J Richard

    2014-09-01

    Hydroxyl radical (OH) and one-electron oxidants that may be endogenously formed through oxidative metabolism, phagocytosis, inflammation and pathological conditions constitute the main sources of oxidatively generated damage to cellular DNA. It is worth mentioning that exposure of cells to exogenous physical agents (UV light, high intensity UV laser, ionizing radiation) and chemicals may also induce oxidatively generated damage to DNA. Emphasis is placed in this short review article on the mechanistic aspects of OH and one-electron oxidant-mediated formation of single and more complex damage (tandem lesions, intra- and interstrand cross-links, DNA-protein cross-links) in cellular DNA arising from one radical hit. This concerns DNA modifications that have been accurately measured using suitable analytical methods such as high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Evidence is provided that OH and one-electron oxidants after generating neutral radicals and base radical cations respectively may partly induce common degradation pathways. In addition, selective oxidative reactions giving rise to specific degradation products of OH and one-electron oxidation reactions that can be used as representative biomarkers of these oxidants have been identified.

  2. Description of bulk inversion asymmetry in the effective-bond-orbital model

    NASA Astrophysics Data System (ADS)

    Cartoixà, X.; Ting, D. Z.-Y.; McGill, T. C.

    2003-12-01

    We have extended the effective-bond-orbital model (EBOM) method [Y. C. Chang, Phys. Rev. B 37, 8215 (1988)] to include the effects of the bulk inversion asymmetry (BIA) present in zinc blendes. This is accomplished without adding to the number of basis states or extending the range of interaction. We have also investigated a variant form of the EBOM proposed in the original formulation that offers improved zone-center behavior, but may also generate spurious solutions in heterostructure calculations due to poor description of bulk zone-boundary band structure. We offer suggestions for avoiding this problem so that this variant form of EBOM may be used safely. In general, we find that the addition of BIA effects in EBOM results in improved descriptions of zone-center band structure, but also in a loss of accuracy far from the Brillouin-zone center. We illustrate the use of the BIA extension with band-structure calculations for bulk GaSb. We show that the spin splitting predicted by the extended EBOM method for an AlSb/GaSb superlattice is in good agreement with kṡp calculations that include BIA effects.

  3. A Conformal Field Theory Description of the Paired and Parafermionic States in the Quantum Hall Effect

    NASA Astrophysics Data System (ADS)

    Cristofano, Gerardo; Maiella, Giuseppe; Marotta, Vincenzo

    We extend the construction of the effective conformal field theory for the Jain hierarchical fillings proposed in Ref. 1 to the description of a quantum Hall fluid at nonstandard fillings ν =(m)/(pm+2). The chiral primary fields are found by using a procedure which induces twisted boundary conditions on the m scalar fields; they appear as composite operators of a charged and neutral component. The neutral modes describe parafermions and contribute to the ground state wave function with a generalized Pfaffian term. Correlators of Ne electrons in the presence of quasi-hole excitations are explicitly given for m=2.

  4. Nuclear-size correction to the Lamb shift of one-electron atoms

    SciTech Connect

    Yerokhin, Vladimir A.

    2011-01-15

    The nuclear-size effect on the one-loop self-energy and vacuum polarization is evaluated for the 1s, 2s, 3s, 2p{sub 1/2}, and 2p{sub 3/2} states of hydrogen-like ions. The calculation is performed to all orders in the nuclear binding strength parameter Z{alpha}. Detailed comparison is made with previous all-order calculations and calculations based on the expansion in the parameter Z{alpha}. Extrapolation of the all-order numerical results obtained toward Z=1 provides results for the radiative nuclear-size effect on the hydrogen Lamb shift.

  5. Effective descriptions of complex quantum systems: path integrals and operator ordering problems

    NASA Astrophysics Data System (ADS)

    Eckern, U.; Gruber, M. J.; Schwab, P.

    2005-09-01

    [Dedicated to Bernhard Mühlschlegel on the occasion ofhis 80th birthday]We study certain aspects of the effective, occasionally called collective, description of complex quantum systems within the framework of the path integral formalism, in which the environment is integrated out. Generalising the standard Feynman-Vernon Caldeira-Leggett model to include a non-linear coupling between particle and environment, and considering a particular spectral density of the coupling, a coordinate-dependent mass (or velocity-dependent potential) is obtained. The related effective quantum theory, which depends on the proper discretisation of the path integral, is derived and discussed. As a result, we find that in general a simple effective low-energy Hamiltonian, in which only the coordinate-dependent mass enters, cannot be formulated. The quantum theory of weakly coupled superconductors and the quantum dynamics of vortices in Josephson junction arrays are physical examples where these considerations, in principle, are of relevance.

  6. One-electron density matrices and energy gradients in second-order electron propagator theory

    NASA Astrophysics Data System (ADS)

    Cioslowski, Jerzy; Ortiz, J. V.

    1992-06-01

    A formalism for evaluation of the effective first-order density matrices associated with second-order electron propagator theory is described. Computer implementation of this formalism affords first-order density properties, such as dipole moments, and energy gradients. Given an initial state with N electrons, this approach enables geometry optimization of the ground and excited electronic states of species with N-1 and N+1 electrons. The performance of the present method is assessed with test calculations on the formyl radical.

  7. Stockholder projector analysis: A Hilbert-space partitioning of the molecular one-electron density matrix with orthogonal projectors

    NASA Astrophysics Data System (ADS)

    Vanfleteren, Diederik; Van Neck, Dimitri; Bultinck, Patrick; Ayers, Paul W.; Waroquier, Michel

    2012-01-01

    A previously introduced partitioning of the molecular one-electron density matrix over atoms and bonds [D. Vanfleteren et al., J. Chem. Phys. 133, 231103 (2010)] is investigated in detail. Orthogonal projection operators are used to define atomic subspaces, as in Natural Population Analysis. The orthogonal projection operators are constructed with a recursive scheme. These operators are chemically relevant and obey a stockholder principle, familiar from the Hirshfeld-I partitioning of the electron density. The stockholder principle is extended to density matrices, where the orthogonal projectors are considered to be atomic fractions of the summed contributions. All calculations are performed as matrix manipulations in one-electron Hilbert space. Mathematical proofs and numerical evidence concerning this recursive scheme are provided in the present paper. The advantages associated with the use of these stockholder projection operators are examined with respect to covalent bond orders, bond polarization, and transferability.

  8. R-matrix-incorporating-time theory of one-electron atomic and molecular systems in intense laser fields

    NASA Astrophysics Data System (ADS)

    Broin, Cathal Ó.; Nikolopoulos, L. A. A.

    2017-02-01

    In this thesis tutorial we discuss the R-matrix-incorporating-time ab initio theoretical framework for the solution of the time-dependent Schrödinger equation of one-electron atomic and molecular systems under strong electromagnetic fields. Within this approach, a division-of-space method is developed with the configuration space of the electron’s coordinates separated over two regions, the inner and outer regions. In the inner region the quantum system’s time-dependent wavefunction is expanded on the eigenstate basis set of its field-free Hamiltonian representation while in the outer region its grid representation is considered. The present tutorial describes in detail the theoretical formulation for one-electron quantum systems. Example calculations are discussed for atomic hydrogen, H, and the molecular hydrogen ion, {{{H}}}2+, in intense laser fields.

  9. Neural evidence for description dependent reward processing in the framing effect.

    PubMed

    Yu, Rongjun; Zhang, Ping

    2014-01-01

    Human decision making can be influenced by emotionally valenced contexts, known as the framing effect. We used event-related brain potentials to investigate how framing influences the encoding of reward. We found that the feedback related negativity (FRN), which indexes the "worse than expected" negative prediction error in the anterior cingulate cortex (ACC), was more negative for the negative frame than for the positive frame in the win domain. Consistent with previous findings that the FRN is not sensitive to "better than expected" positive prediction error, the FRN did not differentiate the positive and negative frame in the loss domain. Our results provide neural evidence that the description invariance principle which states that reward representation and decision making are not influenced by how options are presented is violated in the framing effect.

  10. Description of light nuclei in pionless effective field theory using the stochastic variational method

    NASA Astrophysics Data System (ADS)

    Lensky, Vadim; Birse, Michael C.; Walet, Niels R.

    2016-09-01

    We construct a coordinate-space potential based on pionless effective field theory (EFT) with a Gaussian regulator. Charge-symmetry breaking is included through the Coulomb potential and through two- and three-body contact interactions. Starting with the effective field theory potential, we apply the stochastic variational method to determine the ground states of nuclei with mass number A ≤4 . At next-to-next-to-leading order, two out of three independent three-body parameters can be fitted to the three-body binding energies. To fix the remaining one, we look for a simultaneous description of the binding energy of 4He and the charge radii of 3He and 4He. We show that at the order considered we can find an acceptable solution, within the uncertainty of the expansion. We find that the EFT expansion shows good agreement with empirical data within the estimated uncertainty, even for a system as dense as 4He.

  11. Neural evidence for description dependent reward processing in the framing effect

    PubMed Central

    Yu, Rongjun; Zhang, Ping

    2014-01-01

    Human decision making can be influenced by emotionally valenced contexts, known as the framing effect. We used event-related brain potentials to investigate how framing influences the encoding of reward. We found that the feedback related negativity (FRN), which indexes the “worse than expected” negative prediction error in the anterior cingulate cortex (ACC), was more negative for the negative frame than for the positive frame in the win domain. Consistent with previous findings that the FRN is not sensitive to “better than expected” positive prediction error, the FRN did not differentiate the positive and negative frame in the loss domain. Our results provide neural evidence that the description invariance principle which states that reward representation and decision making are not influenced by how options are presented is violated in the framing effect. PMID:24733998

  12. Initial step of B12-dependent enzymatic catalysis: energetic implications regarding involvement of the one-electron-reduced form of adenosylcobalamin cofactor.

    PubMed

    Kozlowski, Pawel M; Kamachi, Takashi; Kumar, Manoj; Yoshizawa, Kazunari

    2012-02-01

    Density functional theory analysis was performed to elucidate the impact of one-electron reduction upon the initial step of adenosylcobalamin-dependent enzymatic catalysis. The transition state (TS) corresponding to the Co-C bond cleavage and subsequent hydrogen abstraction from the substrate was located. The intrinsic reaction coordinate calculations predicted that the reaction consisting of Co-C5' bond cleavage in [Co(III)(corrin(•))]-Rib (where Rib is ribosyl) and hydrogen-atom abstraction from the CH(3)-CH(2)-CHO substrate occurs in a concerted fashion. The computed activation energy barrier of the reaction (15.0 kcal/mol) was lowered by approximately 54.5% in comparison with the reaction involving the positively charged cofactor model (Im-[Co(III)(corrin)]-Rib(+), where Im is imidazole; energy barrier = 33.0 kcal/mol). The Im base was detached during the TS search in the reaction involving the one-electron-reduced analogue. Thus, to compare the energetics of the two reactions, the axial Im ligand detachment energy for the Im-[Co(III)(corrin(•))]-Rib model was computed [7.6 kcal/mol (gas phase); 4.6 kcal/mol (water)]. Consequently, the effective activation energy barrier for the reaction mediated by the Im-off [Co(III)(corrin(•))]-Rib was estimated to be 22.6 kcal/mol, which implied an overall 31.5% reduction in the energetic demands of the reaction. Considering that the lengthened Co-N(axial) bond has been observed in X-ray crystal structure studies of B(12)-dependent mutases, the catalytic impact induced by one-electron reduction of the cofactor is expected to be higher in the presence of the enzymatic environment.

  13. Relative antioxidant efficiency of a large series of carotenoids in terms of one electron transfer reactions.

    PubMed

    Galano, Annia

    2007-11-08

    The relative antioxidant efficiency, expressed as electron donating capability, of a large series of carotenoids has been studied using density functional theory. Their reactivity toward nine different radicals has been modeled as well as the electron transfer between pairs of carotenoids, one of which is present as a radical cation. The influence of the solvent polarity has also been studied. Torulene was found to be the most easily oxidized carotenoid, followed by lycopene. This higher reactivity is proposed in the present work for the first time, and the potential implications of such a finding are discussed. Since torulene has not been previously studied, compared to other carotenoids in terms of oxidation potentials, further experimental studies are suggested in order to confirm or reject this prediction. Ionization potential seems to be a magnitude calculable at low computational cost that correctly predicts the relative ease of oxidation in a series of carotenoids. The nuclear reorganization energy associated with electron-transfer reactions has been calculated in a very simple but apparently efficient way that allows computation of free energy barriers and relative rate constants in good agreement with the experimental values. In addition, an additive correction is proposed to include the effect of increasing the size of basis sets on the energies of Car(n) --> Car(n-1)(*+) processes. The general agreement between different calculated magnitudes and the corresponding available experimental data supports the predictions from this work.

  14. Two-electron reduction and one-electron oxidation of organic hydroperoxides by human myeloperoxidase.

    PubMed

    Furtmüller, P G; Burner, U; Jantschko, W; Regelsberger, G; Obinger, C

    2000-11-03

    The reaction of native myeloperoxidase (MPO) and its redox intermediate compound I with hydrogen peroxide, ethyl hydroperoxide, peroxyacetic acid, t-butyl hydroperoxide, 3-chloroperoxybenzoic acid and cumene hydroperoxide was studied by multi-mixing stopped-flow techniques. Hydroperoxides are decomposed by MPO by two mechanisms. Firstly, the hydroperoxide undergoes a two-electron reduction to its corresponding alcohol and heme iron is oxidized to compound I. At pH 7 and 15 degrees C, the rate constant of the reaction between 3-chloroperoxybenzoic acid and ferric MPO was similar to that with hydrogen peroxide (1.8x10(7) M(-1) s(-1) and 1.4x10(7) M(-1) s(-1), respectively). With the exception of t-butyl hydroperoxide, the rates of compound I formation varied between 5.2x10(5) M(-1) s(-1) and 2.7x10(6) M(-1) s(-1). Secondly, compound I can abstract hydrogen from these peroxides, producing peroxyl radicals and compound II. Compound I reduction is shown to be more than two orders of magnitude slower than compound I formation. Again, with 3-chloroperoxybenzoic acid this reaction is most effective (6. 6x10(4) M(-1) s(-1) at pH 7 and 15 degrees C). Both reactions are controlled by the same ionizable group (average pK(a) of about 4.0) which has to be in its conjugated base form for reaction.

  15. π- vs σ-radical states of one-electron-oxidized DNA/RNA bases: a density functional theory study.

    PubMed

    Kumar, Anil; Sevilla, Michael D

    2013-10-03

    As a result of their inherent planarity, DNA base radicals generated by one-electron oxidation/reduction or bond cleavage form π- or σ-radicals. While most DNA base systems form π-radicals, there are a number of nucleobase analogues such as one-electron-oxidized 6-azauraci1, 6-azacytosine, and 2-thiothymine or one-electron reduced 5-bromouracil that form more reactive σ-radicals. Elucidating the availability of these states within DNA, base radical electronic structure is important to the understanding of the reactivity of DNA base radicals in different environments. In this work, we address this question by the calculation of the relative energies of π- and σ-radical states in DNA/RNA bases and their analogues. We used density functional theory B3LYP/6-31++G** method to optimize the geometries of π- and σ-radicals in Cs symmetry (i.e., planar) in the gas phase and in solution using the polarized continuum model (PCM). The calculations predict that σ- and π-radical states in one-electron-oxidized bases of thymine, T(N3-H)(•), and uracil, U(N3-H)(•), are very close in energy; i.e., the π-radical is only ca. 4 kcal/mol more stable than the σ-radical. For the one-electron-oxidized radicals of cytosine, C(•+), C(N4-H)(•), adenine, A(•+), A(N6-H)(•), and guanine, G(•+), G(N2-H)(•), G(N1-H)(•), the π-radicals are ca. 16-41 kcal/mol more stable than their corresponding σ-radicals. Inclusion of solvent (PCM) is found to stabilize the π- over σ-radical of each of the systems. U(N3-H)(•) with three discrete water molecules in the gas phase is found to form a three-electron σ bond between the N3 atom of uracil and the O atom of a water molecule, but on inclusion of full solvation and discrete hydration, the π-radical remains most stable.

  16. One-electron oxidation of gemcitabine and analogs: mechanism of formation of C3' and C2' sugar radicals.

    PubMed

    Adhikary, Amitava; Kumar, Anil; Rayala, Ramanjaneyulu; Hindi, Ragda M; Adhikary, Ananya; Wnuk, Stanislaw F; Sevilla, Michael D

    2014-11-05

    Gemcitabine is a modified cytidine analog having two fluorine atoms at the 2'-position of the ribose ring. It has been proposed that gemcitabine inhibits RNR activity by producing a C3'• intermediate via direct H3'-atom abstraction followed by loss of HF to yield a C2'• with 3'-keto moiety. Direct detection of C3'• and C2'• during RNR inactivation by gemcitabine still remains elusive. To test the influence of 2'- substitution on radical site formation, electron spin resonance (ESR) studies are carried out on one-electron oxidized gemcitabine and other 2'-modified analogs, i.e., 2'-deoxy-2'-fluoro-2'-C-methylcytidine (MeFdC) and 2'-fluoro-2'-deoxycytidine (2'-FdC). ESR line components from two anisotropic β-2'-F-atom hyperfine couplings identify the C3'• formation in one-electron oxidized gemcitabine, but no further reaction to C2'• is found. One-electron oxidized 2'-FdC is unreactive toward C3'• or C2'• formation. In one-electron oxidized MeFdC, ESR studies show C2'• production presumably from a very unstable C3'• precursor. The experimentally observed hyperfine couplings for C2'• and C3'• match well with the theoretically predicted ones. C3'• to C2'• conversion in one-electron oxidized gemcitabine and MeFdC has theoretically been modeled by first considering the C3'• and H3O(+) formation via H3'-proton deprotonation and the subsequent C2'• formation via HF loss induced by this proximate H3O(+). Theoretical calculations show that in gemcitabine, C3'• to C2'• conversion in the presence of a proximate H3O(+) has a barrier in agreement with the experimentally observed lack of C3'• to C2'• conversion. In contrast, in MeFdC, the loss of HF from C3'• in the presence of a proximate H3O(+) is barrierless resulting in C2'• formation which agrees with the experimentally observed rapid C2'• formation.

  17. Prototropic Equilibria in DNA Containing One-electron Oxidized GC: Intra-duplex vs. Duplex to Solvent Deprotonation

    PubMed Central

    Adhikary, Amitava; Kumar, Anil; Munafo, Shawn A.; Khanduri, Deepti; Sevilla, Michael D.

    2015-01-01

    By use of ESR and UV-vis spectral studies, this work identifies the protonation states of one-electron oxidized G:C (viz. G•+:C, G(N1-H)•:C(+H+), G(N1-H)•:C, and G(N2-H)•:C) in a DNA oligomer d[TGCGCGCA]2. Benchmark ESR and UV-vis spectra from one electron oxidized 1-Me-dGuo are employed to analyze the spectral data obtained in one-electron oxidized d[TGCGCGCA]2 at various pHs. At pH ≥7, the initial site of deprotonation of one-electron oxidized d[TGCGCGCA]2 to the surrounding solvent is found to be at N1 forming G(N1-H)•:C at 155 K. However, upon annealing to 175 K, the site of deprotonation to the solvent shifts to an equilibrium mixture of G(N1-H)•:C and G(N2-H)•:C. For the first time, the presence of G(N2-H)•:C in a ds DNA-oligomer is shown to be easily distinguished from the other prototropic forms, owing to its readily observable nitrogen hyperfine coupling (Azz(N2)= 16 G). In addition, for the oligomer in H2O, an additional 8 G N2-H proton HFCC is found. This ESR identification is supported by a UV-vis absorption at 630 nm which is characteristic for G(N2-H)• in model compounds and oligomers. We find that the extent of photo-conversion to the C1′ sugar radical (C1′•) in the one-electron oxidized d[TGCGCGCA]2 allows for a clear distinction among the various G:C protonation states which can not be easily distinguished by ESR or UV-vis spectroscopies with this order for the extent of photo-conversion: G•+:C > G(N1-H)•:C(+H+) >> G(N1-H)•:C. We propose that it is the G•+:C form that undergoes deprotonation at the sugar and this requires reprotonation of G within the lifetime of exited state. PMID:21491657

  18. Effects of ultraviolet radiation (type B) on wound exudates, appearance and depth description.

    PubMed

    Onigbinde, A T; Adedoyin, R A; Ojoawo, O A; Johnson, O E; Obembe, A O; Olafimihan, F K; Omiyale, O M; Oniyangi, S

    2010-01-01

    Purulent exudate is one of the clinical signs of decubitus ulcers; and it is indicative of infection. The greatest challenge is the decreasing sensitivity of infective micro-organisms to antibiotics. There appears to be paucity of data on the effect of Ultraviolet radiation on wound exudates and appearance. The main purpose of this study was to determine the effect of ultraviolet radiation (Type B) on wound exudates and appearance of decubitus ulcers. Ten (10) bed-ridden subjects with ascertained bilateral sore from unrelieved pressure in their lower extremities consented to participate in the study. The decubitus ulcers were treated with traditional saline-wet-to-moist (WM) wound dressing. The decubitus ulcers on the left lower extremities were the experimental limbs and were exposed to ultraviolet radiation as adjunct while the right lower limbs served as control and received only the saline-wet-to-moist (WM) wound dressing. The frequency of treatment was 3 times per week for 6 weeks. The type of exudates produced, amount of exudates, wound appearance and depth description were scored on a 5-point likert scale. The data was analyzed using descriptive statistics and non-parametric inferential statistics (Kruska-Wallis test). The result of the Kruskal Wallis test showed that there was significant improvement in the type of exudates produced by the decubitus ulcers of the experimental (left) limbs (X{2} = 33.71, p < 0.00) when compared with the control limbs. Similarly, there was significant reduction in the amount of exudates produced by the decubitus ulcers of the experimental limbs (X{2} = 30.58, p < 0.00) when compared with that of the control. Also, there was significant improvement in the appearance of the decubitus ulcers (X{2} = 33.01, p< 0.00) and depth description of the experimental (left) limbs compared to that of the control (right). This study concluded that Ultraviolet radiation (Type B) can significantly improve the appearance of decubitus ulcers

  19. Kondo effect from a Lorentz-violating domain wall description of superconductivity

    NASA Astrophysics Data System (ADS)

    Bazeia, D.; Brito, F. A.; Mota-Silva, J. C.

    2016-11-01

    We extend recent results on domain wall description of superconductivity in an Abelian Higgs model by introducing a particular Lorentz-violating term. The temperature of the system is interpreted through the fact that the soliton following accelerating orbits is a Rindler observer experiencing a thermal bath. We show that this term can be associated with the Kondo effect, that is, the Lorentz-violating parameter is closely related to the concentration of magnetic impurities living on a superconducting domain wall. We also found that the critical temperature decreasing with the impurity concentration as a non-single-valued function, for the case TK

  20. The effect of simplifying the building description on the numerical modeling of its thermal performance

    SciTech Connect

    Stetiu, C.

    1993-07-01

    A thermal building simulation program is a numerical model that calculates the response of the building envelopes to weather and human activity, simulates dynamic heating and cooling loads, and heating and cooling distribution systems, and models building equipment operation. The scope of the research is to supply the users of such programs with information about the dangers and benefits of simplifying the input to their models. The Introduction describes the advantages of modeling the heat transfer mechanisms in a building. The programs that perform this type of modeling have, however, limitations. The user is therefore often put in the situation of simplifying the floor plans of the building under study, but not being able to check the effects that this approximation introduces in the results of the simulation. Chapter 1 is a description of methods. It also introduces the floor plans for the office building under study and the ``reasonable`` floor plans simplifications. Chapter 2 presents DOE-2, the thermal building simulation program used in the sensitivity study. The evaluation of the accuracy of the DOE-2 program itself is also presented. Chapter 3 contains the sensitivity study. The complicated nature of the process of interpreting the temperature profile inside a space leads to the necessity of defining different building modes. The study compares the results from the model of the detailed building description with the results from the models of the same building having simplified floor plans. The conclusion is reached that a study of the effects of simplifying the floor plans of a building is important mainly for defining the cases in which this approximation is acceptable. Different results are obtained for different air conditioning/load regimes of the building. 9 refs., 24 figs.

  1. A descriptive study of effect-size reporting in research reviews.

    PubMed

    Floyd, Judith A

    2017-06-01

    To describe effect-size reporting in research reviews completed in support of evidence-based practice in nursing. Many research reviews report nurses' critical appraisal of level, quality and overall strength of evidence available to address clinical questions. Several studies of research-review quality suggest effect-size information would be useful to include in these reviews, but none focused on reviewers' attention to effect sizes. Descriptive. One hundred and four reviews indexed in CINAHL as systematic reviews and published from July 2012-February 2014 were examined. Papers were required to be peer-reviewed, written in English, contain an abstract and have at least one nurse author. Reviews were excluded if they did not use critical appraisal methods to address evidence of correlation, prediction or effectiveness. Data from remaining papers (N = 73) were extracted by three or more independent coders using a structured coding form and detailed codebook. Data were stored, viewed and analysed using Microsoft Office Excel(®) spreadsheet functions. Sixteen percent (n = 12) of the sample contained effect-size information. Of the 12, six included all the effect-size information recommended by APA guidelines. Independent of completeness of reporting, seven contained discussion of effect sizes in the paper, but none included effect-size information in abstracts. Research reviews available to practicing nurses often fail to include information needed to accurately assess how much improvement may result from implementation of evidence-based policies, programs, protocols or practices. Manuscript reviewers are urged to hold authors to APA standards for reporting/discussing effect-size information in both primary research reports and research reviews. © 2016 John Wiley & Sons Ltd.

  2. One-electron reduction of 8-bromo-2-aminoadenosine in the aqueous phase: radiation chemical and DFT studies of the mechanism.

    PubMed

    Kaloudis, Panagiotis; D'Angelantonio, Mila; Guerra, Maurizio; Gimisis, Thanasis; Mulazzani, Quinto G; Chatgilialoglu, Chryssostomos

    2008-04-24

    Two tautomeric forms of one-electron oxidized 2-aminoadenosine (2AA) have been produced by reactions of hydrated electrons (e aq-) with 8-bromo-2-aminoadenosine (8-Br-2AA) at natural pH, whereas only one tautomer is formed by oxidation of 2AA. Tailored experiments by pulse radiolysis and time-dependent DFT (TD-B3LYP/6-311G**//B1B95/6-31+G**) calculations allowed the definition of the reaction mechanism in some detail. The electron adducts of 8-Br-2AA protonated at C8 eject Br- and produce the two short-lived tautomers (8 and 9). The first observable species decays by first-order kinetics to produce the second intermediate, which is also obtained by oxidation of 2AA by SO4*-. The rate of tautomerization (k taut = 4.5 x 104 s-1) is strongly accelerated by phosphate and is retarded in D2O (kinetic isotope effect 7). B1B95/6-31+G** calculations showed that the tautomerization is a water-assisted process. In acidic or basic solutions, the "instantaneous" formation of one-electron oxidized 2AA or its deprotonated forms has been produced by reactions of e aq- with 8-Br-2AA. gamma-Radiolysis of 8-Br-2AA in aqueous solutions followed by product studies led to the formation of 2AA as a single product.

  3. Analytic energy gradients for the spin-free exact two-component theory using an exact block diagonalization for the one-electron Dirac Hamiltonian.

    PubMed

    Cheng, Lan; Gauss, Jürgen

    2011-08-28

    We report the implementation of analytic energy gradients for the evaluation of first-order electrical properties and nuclear forces within the framework of the spin-free (SF) exact two-component (X2c) theory. In the scheme presented here, referred to in the following as SFX2c-1e, the decoupling of electronic and positronic solutions is performed for the one-electron Dirac Hamiltonian in its matrix representation using a single unitary transformation. The resulting two-component one-electron matrix Hamiltonian is combined with untransformed two-electron interactions for subsequent self-consistent-field and electron-correlated calculations. The "picture-change" effect in the calculation of properties is taken into account by considering the full derivative of the two-component Hamiltonian matrix with respect to the external perturbation. The applicability of the analytic-gradient scheme presented here is demonstrated in benchmark calculations. SFX2c-1e results for the dipole moments and electric-field gradients of the hydrogen halides are compared with those obtained from nonrelativistic, SF high-order Douglas-Kroll-Hess, and SF Dirac-Coulomb calculations. It is shown that the use of untransformed two-electron interactions introduces rather small errors for these properties. As a first application of the analytic geometrical gradient, we report the equilibrium geometry of methylcopper (CuCH(3)) determined at various levels of theory.

  4. Assessment of effectiveness of geologic isolation systems: a short description of the AEGIS approach

    SciTech Connect

    Silviera, D.J.; Harwell, M.A.; Napier, B.A.; Zellmer, J.T.; Benson, G.L.

    1980-09-01

    To meet licensing criteria and protection standards for HLW disposal, research programs are in progress to determine acceptable waste forms, canisters, backfill materials for the repository, and geological formations. Methods must be developed to evaluate the effectiveness of the total system. To meet this need, methods are being developed to assess the long-term effectiveness of isolating nuclear wastes in geologic formations. This work was started in 1976 in the Waste Isolation Safety Assessment Program (WISAP) and continues in the Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) Program. The evaluation of this long-term effectiveness involves a number of distinct steps. AEGIS currently has the methods for performing these evaluation steps. These methods are continuously being improved to meet the inreasing level of sophistication which will be required. AEGIS develops a conceptual description of the geologic systems and uses computer models to simulate the existing ground-water pathways. AEGIS also uses a team of consulting experts, with the assistance of a computer model of the geologic processes, to develop and evaluate plausible release scenarios. Then other AEGIS computer models are used to simulate the transport of radionuclides to the surface and the resultant radiation doses to individuals and populations. (DLC)

  5. Nursing students' perspectives on clinical instructors' effective teaching strategies: A descriptive study.

    PubMed

    Valiee, Sina; Moridi, Glorokh; Khaledi, Shahnaz; Garibi, Fardin

    2016-01-01

    An important factor contributing to the quality of clinical education is instructors' teaching performance. The aim of this study was to identify clinical instructors' most effective teaching strategies from nursing and midwifery students' perspectives. This was a descriptive cross-sectional study. All third- and fourth-year bachelor's nursing and midwifery students studying at the Nursing and Midwifery Faculty of Kurdistan University of Medical Sciences were recruited to the study by using the census method. The study instrument consisted of a demographic questionnaire and the self-report 30-item Clinical Instructors' Effective Teaching Strategies Inventory. The SPSS v.16.0 was used for data analysis. The most effective teaching strategies of clinical instructors from nursing and midwifery students' perspectives were respectively 'treating students, clients, and colleagues with respect' and 'being eager for guiding students and manage their problems'. Clinical instructors need to be eager for education and also be able to establish effective communication with students. Empowering clinical instructors in specialized and technical aspects of clinical education seems necessary. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Electrochemical and Spectroscopic Evidence on the One-Electron Reduction of U(VI) to U(V) on Magnetite

    SciTech Connect

    Yuan, Ke; Ilton, Eugene S.; Antonio, Mark R.; Li, Zhongrui; Cook, Peter J.; Becker, Udo

    2015-05-19

    Reduction of U(VI) to U(VI) on mineral surfaces is often considered a one-step two-electron process. However, stabilized U(V), with no evidence of U(IV), found in recent studies Indicates U(VI) can undergo a one-electron reduction to U(V) without further progression to U(VI),. We investigated reduction pathways of uranium by reducing U(VI) electrochemically on a, magnetite electrode at,pH 3.4. Cyclic voltammetry confirms the one-electron reduction of U(VI) . Formation of nanosize uranium precipitates on the magnetite surface at reducing potentials and dissolution of the solids at oxidizing potentials are observed by in situ electrochemical atomic force microscopy. XPS, analysis Of the magnetite electrodes polarized in uranium solutions at voltages - from -0.1 to -0.9 V (E-U(VI)/U(V)(0)= -0.135 V vs Ag/AgCl) show the presence of, only U(V) and U(VI). The sample with the highest U(V)/U(VI) ratio was prepared at -0.7 V, where the longest average U-O-axial distance of 2.05 + 0.01 A was evident in the same sample revealed by extended X-ray absorption fine structure analysis. The results demonstrate that the electrochemical reduction of U(VI) On magnetite only yields,U(V), even at a potential of -0.9 V, which favors the one-electron reduction mechanism, U(V) does not disproportionate but stabilizes on magnetite through precipitation Of mixed-valence state -U(V)/U(VI) solids.

  7. Electrochemical and spectroscopic evidence on the one-electron reduction of U(VI) to U(V) on magnetite

    SciTech Connect

    Yuan, Ke; Ilton, Eugene S.; Antonio, Mark R.; Li, Zhongrui; Cook, Peter J.; Becker, Udo

    2015-05-19

    Reduction of U(VI) to U(IV) on mineral surfaces has been considered as a one-step two electron process. However, stabilized U(V), with no evidence of U(IV), found in recent studies indicates U(VI) can undergo a one electron reduction to U(V) without further progression to U(IV). We investigated the mechanisms of uranium reduction by reducing U(VI) electrochemically on a magnetite electrode at pH 3.4 . The one electron reduction of U(VI) was first confirmed using the cyclic voltammetry method. Formation of nano-size uranium precipitates on the surface of magnetite at reducing potentials and dissolution of the solids at oxidizing potentials were observed by in situ electrochemical AFM. XPS analysis of the magnetite electrodes polarized in uranium solutions at voltages from 0.1 ~ 0.9 V (vs. Ag/AgCl) showed the presence of only U(V) and U(VI). The highest amount of U(V) relative to U(VI) was prepared at 0.7 V, where the longest average U–Oaxial distance of 2.05 ± 0.01 Å was evident in the same sample revealed by EXAFS analysis. The results demonstrate that the electrochemical reduction of U(VI) on magnetite only yields U(V), even at a potential of 0.9 V, which favors the one-electron reduction mechanism. U(V) did not disproportionate but stabilized on magnetite through precipitation of mixed-valence state U(VI)/U(V) solids.

  8. Electrochemical and Spectroscopic Evidence on the One-Electron Reduction of U(VI) to U(V) on Magnetite.

    PubMed

    Yuan, Ke; Ilton, Eugene S; Antonio, Mark R; Li, Zhongrui; Cook, Peter J; Becker, Udo

    2015-05-19

    Reduction of U(VI) to U(IV) on mineral surfaces is often considered a one-step two-electron process. However, stabilized U(V), with no evidence of U(IV), found in recent studies indicates U(VI) can undergo a one-electron reduction to U(V) without further progression to U(IV). We investigated reduction pathways of uranium by reducing U(VI) electrochemically on a magnetite electrode at pH 3.4. Cyclic voltammetry confirms the one-electron reduction of U(VI) to U(V). Formation of nanosize uranium precipitates on the magnetite surface at reducing potentials and dissolution of the solids at oxidizing potentials are observed by in situ electrochemical atomic force microscopy. XPS analysis of the magnetite electrodes polarized in uranium solutions at voltages from -0.1 to -0.9 V (E(0)(U(VI)/U(V))= -0.135 V vs Ag/AgCl) show the presence of only U(V) and U(VI). The sample with the highest U(V)/U(VI) ratio was prepared at -0.7 V, where the longest average U-O(axial) distance of 2.05 ± 0.01 Å was evident in the same sample revealed by extended X-ray absorption fine structure analysis. The results demonstrate that the electrochemical reduction of U(VI) on magnetite only yields U(V), even at a potential of -0.9 V, which favors the one-electron reduction mechanism. U(V) does not disproportionate but stabilizes on magnetite through precipitation of mixed-valence state U(V)/U(VI) solids.

  9. One-electron spectra and susceptibilities of the three-dimensional electron gas from self-consistent solutions of Hedin's equations

    NASA Astrophysics Data System (ADS)

    Kutepov, A. L.; Kotliar, G.

    2017-07-01

    A few approximate schemes to solve the Hedin equations self-consistently introduced in Phys. Rev. B 94, 155101 (2016), 10.1103/PhysRevB.94.155101 are explored and tested for the three-dimensional (3D) electron gas at metallic densities. We calculate one-electron spectra, dielectric properties, compressibility, and correlation energy. Considerable reduction in the calculated bandwidth (as compared to the self-consistent G W result) has been found when vertex correction was used for both polarizability and self-energy. Generally, it is advantageous to obtain the diagrammatic representation of polarizability from the definition of this quantity as a functional derivative of the electronic density with respect to the total field (external plus induced). For self-energy, the first-order vertex correction seems to be sufficient for the range of densities considered. Whenever it is possible, we compare the accuracy of our vertex-corrected schemes with the accuracy of the self-consistent quasiparticle G W approximation (QSGW), which is less expensive computationally. We show that the QSGW approach performs poorly and we relate this poor performance with an inaccurate description of the screening in the QSGW method (with an error comprising a factor 2-3 in the physically important range of momenta).

  10. Scavenging of the one-electron reduction product from nisoldipine with relevant thiols: electrochemical and EPR spectroscopic evidences.

    PubMed

    Núñez-Vergara, L J; Díaz-Araya, G; Olea-Azar, C; Atria, A M; Bollo-Dragnic, S; Squella, J A

    1998-11-01

    To determine the formation of the one-electron reduction product from nisoldipine and its reactivity with relevant thiols in mixed medium. Cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) techniques were used to determine the one-electron reduction product corresponding to the nitro radical anion. CV was employed to assess both the rate constants corresponding to the decay of the radicals and its interaction with relevant thiols. The nisoldipine radical anion follows second order kinetics, with an association rate constant of 283+/-16 l mol(-1) sec(-1). Nitro radical anion from nisoldipine significantly reacted with thiol compounds. This reactivity was significantly higher than the natural decay of the radical in mixed medium. EPR spectra recorded in situ using DMF/ 0.1 N NaOH (pH 13) confirmed the formation of the nitro radical anion, giving a well-resolved spectra in 35 lines using 0.1 G modulation. Electrochemical and EPR data indicated that all the tested thiols scavenged the nitro radical anion from nisoldipine. The following tentative order of reactivity towards the thiols can be proposed: cysteamine approximately glutathione > N-acetylcysteine > captopril > penicillamine.

  11. One-electron oxidation of ergothioneine and analogues investigated by pulse radiolysis: redox reaction involving ergothioneine and vitamin C.

    PubMed Central

    Asmus, K D; Bensasson, R V; Bernier, J L; Houssin, R; Land, E J

    1996-01-01

    Redox reactions of endogenous and exogenous sulphur-containing compounds are involved in protection against oxidative damage arising from the incidence and/or treatment of many diseases, including cancer. We have investigated, via pulse radiolysis, the one-electron oxidation of ergothioneine, a molecule with antioxidant properties which is detected at millimolar concentrations in certain tissues and fluids subject to oxidative stress, including erythrocytes and plasma. The spectrum of the transient species, assigned to the product of one-electron oxidation, observed after reaction of ergothioneine with the oxidizing radicals OH., N3. and CCl3O2. has a maximum absorption at 520 nm and is very similar to that obtained by oxidation of analogous molecules such as 2-mercaptoimidazole, 1-methyl-2-mercaptoimidazole, S-methyl- and S,N-dimethyl-ergothioneine. In the presence of vitamin C, the oxidized form of ergothioneine is repaired by a rapid reduction (k = 6.3 x 10(8) M(-1).s(-1)) producing ascorbyl radicals. This co-operative interaction between ergothionine and ascorbate, similar to that previously observed between vitamin E and ascorbate, may contribute to essential biological redox protection. PMID:8615839

  12. One-electron Initiated Two-electron Oxidation of Water by Aluminum Porphyrins with Earth's Most Abundant Metal Ion.

    PubMed

    Kuttassery, Fazalurahman; Mathew, Siby; Sagawa, Shogo; Remello, Sebastian Nybin; Thomas, Arun; Yamamoto, Daisuke; Onuki, Satomi; Nabetani, Yu; Tachibana, Hiroshi; Inoue, Haruo

    2017-03-20

    We report here a new molecular catalyst for efficient water splitting, aluminum porphyrins (tetra-methylpyridiniumylporphyrinatealuminum: AlTMPyP), containing the Earth's most abundant metal as the central ion. One-electron oxidation of the aluminum porphyrin initiates the two-electron oxidation of water to form hydrogen peroxide as the primary reaction product with the lowest known overpotential (97 mV). The aluminum-peroxo complex was clearly detected by a cold-spray ionization mass-spectrometry in HRMS mode and the structure of the intermediate was further confirmed using laser-Raman spectroscopy, indicating the hydroperoxy complex of AlTMPyP to be the key intermediate in the reaction. The two-electron oxidation of water to form hydrogen peroxide was essentially quantitative, with a Faradaic efficiency of 99%. The catalytic reaction was found to be highly efficient, with a turnover frequency up to ~ 2 × 10⁴ s¯¹. A reaction mechanism is proposed involving oxygen-oxygen bond formation by the attack of a hydroxide ion on the oxyl-radical-like axial ligand oxygen atom in the one-electron-oxidized form of AlTMPyP(O¯)₂, followed by a second electron transfer to the electrode.

  13. A lifting surface computer code with jet-in-crossflow interference effects. Volume 1: Theoretical description

    NASA Technical Reports Server (NTRS)

    Furlong, K. L.; Fearn, R. L.

    1983-01-01

    A method is proposed to combine a numerical description of a jet in a crossflow with a lifting surface panel code to calculate the jet/aerodynamic-surface interference effects on a V/STOL aircraft. An iterative technique is suggested that starts with a model for the properties of a jet/flat plate configuration and modifies these properties based on the flow field calculated for the configuration of interest. The method would estimate the pressures, forces, and moments on an aircraft out of ground effect. A first-order approximation to the method suggested is developed and applied to two simple configurations. The first-order approximation is a noniterative precedure which does not allow for interactions between multiple jets in a crossflow and also does not account for the influence of lifting surfaces on the jet properties. The jet/flat plate model utilized in the examples presented is restricted to a uniform round jet injected perpendicularly into a uniform crossflow for a range of jet-to-crossflow velocity ratios from three to ten.

  14. Theoretical approach to description of time-dependent nitric oxide effects in the vasculature.

    PubMed

    Seraya, I P; Nartsissov, Ya R

    2002-01-01

    Nitric oxide (NO) is one of the most important signal compounds in a living cell. As a typical free radical it has both toxic and physiological effects and their balance is determined by a spatial distribution of NO concentration. Moreover, some biological functions, especially NO-mediated relaxation of blood vessels, have to be time-limited. In order to circumscribe this phenomenon non steady-state mathematical model has been used for description of nitric oxide diffusion in vascular smooth muscle. It was shown that the microvascular relaxation could be observed even after a short time of NO production in the endothelium. This time is up to 3 times below that needed to reach the steady-state spatial NO gradient. However, the effect of nitric oxide essentially depends on the rate of NO production and blood vessel diameter. Furthermore, non steady-state nitric oxide concentration gradient was represented as an analytical function of time and coordinate. It is essential that this function describes a common case of one-dimensional diffusion of uncharged low-mass molecules. Thus, the results can be used for calculation of an upper estimation of experimental data.

  15. Coarse-graining the dynamics of a driven interface in the presence of mobile impurities: effective description via diffusion maps.

    PubMed

    Sonday, Benjamin E; Haataja, Mikko; Kevrekidis, Ioannis G

    2009-09-01

    Developing effective descriptions of the microscopic dynamics of many physical phenomena can both dramatically enhance their computational exploration and lead to a more fundamental understanding of the underlying physics. Previously, an effective description of a driven interface in the presence of mobile impurities, based on an Ising variant model and a single empirical coarse variable, was partially successful [M. Haataja, Phys. Rev. Lett. 92, 160603 (2004)]; yet it underlined the necessity of selecting additional coarse variables in certain parameter regimes. In this paper we use a data mining approach to help identify the coarse variables required. We discuss the implementation of this diffusion map approach, the selection of a similarity measure between system snapshots required in the approach, and the correspondence between empirically selected and automatically detected coarse variables. We conclude by illustrating the use of the diffusion map variables in assisting the atomistic simulations and we discuss the translation of information between fine and coarse descriptions using lifting and restriction operators.

  16. Communication: satisfying fermionic statistics in the modeling of open time-dependent quantum systems with one-electron reduced density matrices.

    PubMed

    Head-Marsden, Kade; Mazziotti, David A

    2015-02-07

    For an open, time-dependent quantum system, Lindblad derived the most general modification of the quantum Liouville equation in the Markovian approximation that models environmental effects while preserving the non-negativity of the system's density matrix. While Lindblad's modification is correct for N-electron density matrices, solution of the Liouville equation with a Lindblad operator causes the one-electron reduced density matrix (1-RDM) to violate the Pauli exclusion principle. Consequently, after a short time, the 1-RDM is not representable by an ensemble N-electron density matrix (not ensemble N-representable). In this communication, we derive the necessary and sufficient constraints on the Lindbladian matrix within the Lindblad operator to ensure that the 1-RDM remains N-representable for all time. The theory is illustrated by considering the relaxation of an excitation in several molecules F2, N2, CO, and BeH2 subject to environmental noise.

  17. Electromagnetic Structure of Two- and Three-Nucleon Systems: An Effective Field Theory Description

    NASA Astrophysics Data System (ADS)

    Phillips, Daniel R.

    2016-10-01

    I discuss the use of chiral effective field theory (χEFT) to describe electromagnetic reactions in the two- and three-nucleon systems. I review the results of χEFT power counting for charge and current operators up to [Formula: see text] relative to leading order, before showing that renormalization-group arguments imply that short-distance electromagnetic operators play a larger role than suggested by this standard counting. A detailed examination of χEFT's predictions for the electromagnetic form factors of deuterium and the trinucleons, and for the threshold captures np→dγ and nd→tγ, enables a critical appraisal of the theory's performance in these contexts. Recent χEFT calculations using the [Formula: see text] chiral perturbation theory (χPT) potential yielded both form factors that agree with experimental data for Q2<0.25 GeV2 and an excellent description of the challenging threshold captures. Short-distance M1 operators are essential to this success, and the addition of a short-distance part of the nucleon-nucleon charge operator produces precise predictions of the deuteron charge and quadrupole form factors in this kinematic domain.

  18. Effect of grape seed extract on descriptive sensory analysis of ground chicken during refrigerated storage.

    PubMed

    Brannan, R G

    2009-04-01

    Descriptive sensory analysis, instrumental color, yield, pH, water activity, and binding strength were determined on ground chicken breast and thigh with or without grape seed extract (GSE) during refrigerated storage. In chicken breast, GSE inhibited the intensity of musty and rancid odor, and rancid flavor compared to control patties, but GSE caused significantly darker (L(∗)), redder (a(∗)), and less yellow (b(∗)) patties. No differences were observed for pH, water activity, or yield, though differences were observed for binding strength. In chicken thigh, sensory scores were significantly different for 14 of 15 sensory attributes, although the differences were due to storage time or precooking, not the presence of GSE. GSE caused significantly darker sensory scores and L(∗) values, and redder (a(∗)) and less yellow (b(∗)) patties. Differences in binding strength and yield were attributable to precooking, not the presence of GSE. GSE may be an effective antioxidant in precooked chicken breast systems.

  19. Redox equilibration after one-electron reduction of cytochrome c oxidase: radical formation and a possible hydrogen relay mechanism.

    PubMed

    Ashe, Damian; Alleyne, Trevor; Wilson, Michael; Svistunenko, Dimitri; Nicholls, Peter

    2014-07-15

    Kinetic studies using UV/visible and EPR spectroscopy were carried out to follow the distribution of electrons within beef heart cytochrome c oxidase (CcO), both active and cyanide-inhibited, following addition of reduced cytochrome c as electron donor. In the initial one-electron reduced state the electron is shared between three redox centers, heme a, CuA and a third site, probably CuB. Using a rapid freeze system and the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) a protein radical was also detected. The EPR spectrum of the DMPO adduct of this radical was consistent with tyrosyl radical capture. This may be a feature of a charge relay mechanism involved in some part of the CcO electron transfer system from bound cytochrome c via CuA and heme a to the a3CuB binuclear center. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. One-electron oxidation of mitomycin C and its corresponding peroxyl radicals. A steady-state and pulse radiolysis study

    NASA Astrophysics Data System (ADS)

    Getoff, Nikola; Solar, Sonja; Quint, Ruth M.

    1997-12-01

    The one-electron oxidation of Mitomycin C (MMC) as well as the formation of the corresponding peroxyl radicals were investigated by both steady-state and pulse radiolysis. The steady-state MMC-radiolysis by OH-attack followed at both absorption bands showed different yields: at 218 nm G i (-MMC) = 3.0 and at 364 nm G i (-MMC) = 3.9, indicating the formation of various not yet identified products, among which ammonia was determined, G(NH 3) = 0.81. By means of pulse radiolysis it was established a total κ (OH + MMC) = (5.8 ± 0.2) × 10 9 dm 3 mol -1 s -1. The transient absorption spectrum from the one-electron oxidized MMC showed absorption maxima at 295 nm ( ɛ = 9950 dm 3 mol -1 cm t-1 ), 410 nm ( ɛ = 1450 dm 3 mol -1 cm -1) and 505 nm ( ɛ = 5420 dm 3 mol -1 cm -1). At 280-320 and 505 nm and above they exhibit in the first 150 μs a first order decay, κ1 = (0.85 ± 0.1) × 10 3 s -1, and followed upto ms time range, by a second order decay, 2 κ = (1.3 ± 0.3) × 10 8 dm 3 mol -1 s -1. Around 410 nm the kinetics are rather mixed and could not be resolved. The steady-state MMC-radiolysis in the presence of oxygen featured a proportionality towards the absorbed dose for both MMC-absorption bands, resulting in a G i (-MMC) = 1.5. Among several products ammonia-yield was determined G(NH 3) = 0.52. The formation of MMC-peroxyl radicals was studied by pulse radiolysis, likewise in neutral aqueous solution, but saturated with a gas mixture of 80% N 2O and 20% O 2. The maxima of the observed transient spectrum are slightly shifted compared to that of the one-electron oxidized MMC-species, namely: 290 nm ( ɛ = 10100 dm 3 mol -1 cm -1), 410 nm ( ɛ = 2900 dm 3 mol -1 cm -1) and 520 nm ( ɛ = 5500 dm 3 mol -1 cm -1). The O 2-addition to the MMC-one-electron oxidized transients was found to be at 290 to 410 nm gk(MMC·OH + O 2) = 5 × 10 7 dm 3 mol -1 s -1, around 480 nm κ = 1.6 × 10 8 dm 3 mol -1 s -1 and at 510 nm and above, κ = 3 × 10 8 dm 3 mol -1 s -1. The

  1. Pulsed ELDOR spectroscopy of the Mo(V)/Fe(III) state of sulfite oxidase prepared by one-electron reduction with Ti(III) citrate.

    PubMed

    Codd, Rachel; Astashkin, Andrei V; Pacheco, Andrew; Raitsimring, Arnold M; Enemark, John H

    2002-03-01

    The titration of chicken liver sulfite oxidase (SO) with the one-electron reductant Ti(III) citrate, at pH 7.0, results in nearly quantitative selective reduction of the Mo(VI) center to Mo(V), while the b-type heme center remains in the fully oxidized Fe(III) state. The selective reduction of the Mo(VI/V) couple has been established from electronic and EPR spectra. The electronic spectrum of the Fe(III) heme center is essentially unchanged during the titration, and the continuous wave (CW)-EPR spectrum shows the appearance of the well-known Mo(V) signal due to the low pH ( lpH) form of SO. Further confirmation of the selective formation of the Mo(V)/Fe(III) form of SO is provided by the approximately 1:1 ratio of the integrated intensities of the Mo(V) and low-spin Fe(III) EPR signals after addition of one equivalent of Ti(III). The selective generation of the Mo(V)/Fe(III) form of SO is unexpected, considering that previous microcoulometry and flash photolysis investigations have indicated that the Mo(VI/V) and Fe(III/II) couples of SO have similar reduction potentials at pH 7. The nearly quantitative preparation of the one-electron reduced Mo(V)/Fe(III) form of SO by reduction with Ti(III) has enabled the interaction between these two paramagnetic metal centers, which are linked by a flexible loop with no secondary structure, to be investigated for the first time by variable-frequency pulsed electron-electron double resonance (ELDOR) spectroscopy. The ELDOR kinetics were obtained from frozen solutions at 4.2 K at several microwave frequencies by pumping on the narrow Mo(V) signal and observing the effect on the Fe(III) primary echo at both higher and lower frequencies within the microwave C-band region. The ELDOR data indicate that freezing the solution of one-electron reduced SO produces localized regions where the concentration of SO approaches that in the crystal structure, which results in the interpair interactions being the dominant dipolar interaction

  2. Theoretical study of the protonation of the one-electron-reduced guanine-cytosine base pair by water.

    PubMed

    Hsu, Sodio C N; Wang, Tzu-Pin; Kao, Chai-Lin; Chen, Hui-Fen; Yang, Po-Yu; Chen, Hsing-Yin

    2013-02-21

    Prototropic equilibria in ionized DNA play an important role in charge transport and radiation damage of DNA and, therefore, continue to attract considerable attention. Although it is well-established that electron attachment will induce an interbase proton transfer from N1 of guanine (G) to N3 of cytosine (C), the question of whether the surrounding water in the major and minor grooves can protonate the one-electron-reduced G:C base pair still remains open. In this work, density functional theory (DFT) calculations were employed to investigate the energetics and mechanism for the protonation of the one-electron-reduced G:C base pair by water. Through the calculations of thermochemical cycles, the protonation free energies were estimated to be in the range of 11.6-14.2 kcal/mol. The calculations for the models of C(•-)(H(2)O)(8) and G(-H1)(-)(H(2)O)(16), which were used to simulate the detailed processes of protonation by water before and after the interbase proton transfer, respectively, revealed that the protonation proceeds through a concerted double proton transfer involving the water molecules in the first and second hydration shells. Comparing the present results with the rates of interbase proton transfer and charge transfer along DNA suggests that protonation on the C(•-) moiety is not competitive with interbase proton transfer, but the possibility of protonation on the G(-H1)(-) moiety after interbase proton transfer cannot be excluded. Electronic-excited-state calculations were also carried out by the time-dependent DFT approach. This information is valuable for experimental identification in the future.

  3. Theoretical description of protein field effects on electronic excitations of biological chromophores.

    PubMed

    Varsano, Daniele; Caprasecca, Stefano; Coccia, Emanuele

    2017-01-11

    Photoinitiated phenomena play a crucial role in many living organisms. Plants, algae, and bacteria absorb sunlight to perform photosynthesis, and convert water and carbon dioxide into molecular oxygen and carbohydrates, thus forming the basis for life on Earth. The vision of vertebrates is accomplished in the eye by a protein called rhodopsin, which upon photon absorption performs an ultrafast isomerisation of the retinal chromophore, triggering the signal cascade. Many other biological functions start with the photoexcitation of a protein-embedded pigment, followed by complex processes comprising, for example, electron or excitation energy transfer in photosynthetic complexes. The optical properties of chromophores in living systems are strongly dependent on the interaction with the surrounding environment (nearby protein residues, membrane, water), and the complexity of such interplay is, in most cases, at the origin of the functional diversity of the photoactive proteins. The specific interactions with the environment often lead to a significant shift of the chromophore excitation energies, compared with their absorption in solution or gas phase. The investigation of the optical response of chromophores is generally not straightforward, from both experimental and theoretical standpoints; this is due to the difficulty in understanding diverse behaviours and effects, occurring at different scales, with a single technique. In particular, the role played by ab initio calculations in assisting and guiding experiments, as well as in understanding the physics of photoactive proteins, is fundamental. At the same time, owing to the large size of the systems, more approximate strategies which take into account the environmental effects on the absorption spectra are also of paramount importance. Here we review the recent advances in the first-principle description of electronic and optical properties of biological chromophores embedded in a protein environment. We show

  4. Theoretical description of protein field effects on electronic excitations of biological chromophores

    NASA Astrophysics Data System (ADS)

    Varsano, Daniele; Caprasecca, Stefano; Coccia, Emanuele

    2017-01-01

    Photoinitiated phenomena play a crucial role in many living organisms. Plants, algae, and bacteria absorb sunlight to perform photosynthesis, and convert water and carbon dioxide into molecular oxygen and carbohydrates, thus forming the basis for life on Earth. The vision of vertebrates is accomplished in the eye by a protein called rhodopsin, which upon photon absorption performs an ultrafast isomerisation of the retinal chromophore, triggering the signal cascade. Many other biological functions start with the photoexcitation of a protein-embedded pigment, followed by complex processes comprising, for example, electron or excitation energy transfer in photosynthetic complexes. The optical properties of chromophores in living systems are strongly dependent on the interaction with the surrounding environment (nearby protein residues, membrane, water), and the complexity of such interplay is, in most cases, at the origin of the functional diversity of the photoactive proteins. The specific interactions with the environment often lead to a significant shift of the chromophore excitation energies, compared with their absorption in solution or gas phase. The investigation of the optical response of chromophores is generally not straightforward, from both experimental and theoretical standpoints; this is due to the difficulty in understanding diverse behaviours and effects, occurring at different scales, with a single technique. In particular, the role played by ab initio calculations in assisting and guiding experiments, as well as in understanding the physics of photoactive proteins, is fundamental. At the same time, owing to the large size of the systems, more approximate strategies which take into account the environmental effects on the absorption spectra are also of paramount importance. Here we review the recent advances in the first-principle description of electronic and optical properties of biological chromophores embedded in a protein environment. We show

  5. Effect of postmortem deboning time on sensory descriptive flavor and texture profiles of cooked boneless skinless chicken thighs

    USDA-ARS?s Scientific Manuscript database

    Three replicate trials were conducted to investigate the effect of deboning time on sensory descriptive profiles of cooked boneless skinless thigh meat (iliotibialis, iliofibularis and the femoritibialis). Carcasses (42-d old birds) were obtained from a commercial processing plant. Thighs were hot-b...

  6. A descriptive survey study on the effect of age on quality of life following stoma surgery.

    PubMed

    Wong, Selina K; Young, Pang Y; Widder, Sandy; Khadaroo, Rachel G

    2013-12-01

    The number of operative procedures involving the creation of an intestinal stoma is likely to increase as the population ages. Understanding the role of age on postoperative outcomes such as quality of life (QoL) and self-efficacy is critical to developing appropriate supportive strategies. A descriptive survey study was conducted among 18 patients (11 men seven women, age range 47 to 90 years) who had an intestinal ostomy created during a 3-year period at the University of Alberta Hospital in Edmonton, Alberta, Canada. The Stoma Quality of Life Survey and a self-efficacy survey examining self-care, activities of daily living, and instrumental activities of daily living were administered. Patient records were obtained through a retrospective chart review; of the 57 patients identified, 18 were still alive, had not undergone stoma reversal, were cognitively competent, and agreed to participate. Seven patients were <65 years old and 11 were ≥65 years old. Of those, four patients had their stoma since 2009, four patients since 2010, and 10 patients since 2011. Although older patients had more comorbidities and higher mortality following the surgery (46.1% for patients >65 versus 26.1%, for patients <65 years old), no statistically significant difference was found between the two groups for stoma-associated QoL and self-efficacy scores. In patients who had stoma surgery in 2011, older patients on average had higher QoL scores (65.21 versus 61.87, maximum score 100, P = 0.56), but lower self-efficacy scores (32.50 versus 35.25, maximum score 40, P = 0.50). These findings are similar to previously reported study results. However, the small study sample size limits analysis of the variables that may affect QoL in stoma patients. This study supports the need for additional prospective studies to help clinicians develop effective support strategies.

  7. Density functional description of size-dependent effects at nucleation on neutral and charged nanoparticles

    NASA Astrophysics Data System (ADS)

    Shchekin, Alexander K.; Lebedeva, Tatiana S.

    2017-03-01

    A numerical study of size-dependent effects in the thermodynamics of a small droplet formed around a solid nanoparticle has been performed within the square-gradient density functional theory. The Lennard-Jones fluid with the Carnahan-Starling model for the hard-sphere contribution to intermolecular interaction in liquid and vapor phases and interfaces has been used for description of the condensate. The intermolecular forces between the solid core and condensate molecules have been taken into account with the help of the Lennard-Jones part of the total molecular potential of the core. The influence of the electric charge of the particle has been considered under assumption of the central Coulomb potential in the medium with dielectric permittivity depending on local condensate density. The condensate density profiles and equimolecular radii for equilibrium droplets at different values of the condensate chemical potential have been computed in the cases of an uncharged solid core with the molecular potential, a charged core without molecular potential, and a core with joint action of the Coulomb and molecular potentials. The appearance of stable equilibrium droplets even in the absence of the electric charge has been commented. As a next step, the capillary, disjoining pressure, and electrostatic contributions to the condensate chemical potential have been considered and compared with the predictions of classical thermodynamics in a wide range of values of the droplet and the particle equimolecular radii. With the help of the found dependence of the condensate chemical potential in droplet on the droplet size, the activation barrier for nucleation on uncharged and charged particles has been computed as a function of the vapor supersaturation. Finally, the work of droplet formation and the work of wetting the particle have been found as functions of the droplet size.

  8. Dynamic approach to description of entrance channel effects in angular distributions of fission fragments

    NASA Astrophysics Data System (ADS)

    Eremenko, D. O.; Drozdov, V. A.; Fotina, O. V.; Platonov, S. Yu.; Yuminov, O. A.

    2016-07-01

    Background: It is well known that the anomalous behavior of angular anisotropies of fission fragments at sub- and near-barrier energies is associated with a memory of conditions in the entrance channel of the heavy-ion reactions, particularly, deformations and spins of colliding nuclei that determine the initial distributions for the components of the total angular momentum over the symmetry axis of the fissioning system and the beam axis. Purpose: We develop a new dynamic approach, which allows the description of the memory effects in the fission fragment angular distributions and provides new information on fusion and fission dynamics. Methods: The approach is based on the dynamic model of the fission fragment angular distributions which takes into account stochastic aspects of nuclear fission and thermal fluctuations for the tilting mode that is characterized by the projection of the total angular momentum onto the symmetry axis of the fissioning system. Another base of our approach is the quantum mechanical method to calculate the initial distributions over the components of the total angular momentum of the nuclear system immediately following complete fusion. Results: A method is suggested for calculating the initial distributions of the total angular momentum projection onto the symmetry axis for the nuclear systems formed in the reactions of complete fusion of deformed nuclei with spins. The angular distributions of fission fragments for the 16O+232Th,12C+235,236,238, and 13C+235U reactions have been analyzed within the dynamic approach over a range of sub- and above-barrier energies. The analysis allowed us to determine the relaxation time for the tilting mode and the fraction of fission events occurring in times not larger than the relaxation time for the tilting mode. Conclusions: It is shown that the memory effects play an important role in the formation of the angular distributions of fission fragments for the reactions induced by heavy ions. The

  9. Hydroxyl ion addition to one-electron oxidized thymine: Unimolecular interconversion of C5 to C6 OH-adducts

    PubMed Central

    Adhikary, Amitava; Kumar, Anil; Heizer, Alicia N.; Palmer, Brian J.; Pottiboyina, Venkata; Liang, Yong; Wnuk, Stanislaw F.; Sevilla, Michael D.

    2013-01-01

    In this work, addition of OH− to one-electron oxidized thymidine (dThd) and thymine nucleotides in basic aqueous glasses is investigated. At pHs ca. 9–10 where the thymine base is largely deprotonated at N3, one-electron oxidation of the thymine base by Cl2•− at ca. 155 K results in formation of a neutral thyminyl radical, T(−H)•. Assignment to T(−H)• is confirmed by employing 15N substituted 5'-TMP. At pH ≥ ca. 11.5, formation of the 5-hydroxythymin-6-yl radical, T(5OH)•, is identified as a metastable intermediate produced by OH− addition to T(−H)• at C5 at ca. 155 K. Upon further annealing to ca. 170 K, T(5OH)• readily converts to the 6-hydroxythymin-5-yl radical, T(6OH)•. One-electron oxidation of N3-methyl-thymidine (N3-Me-dThd) by Cl2•− at ca. 155 K produces the cation radical (N3-Me-dThd•+) for which we find a pH dependent competition between deprotonation from the methyl group at C5 and addition of OH− to C5. At pH 7 the 5-methyl deprotonated species is found; however, at pH ca. 9, N3-Me-dThd•+ produces T(5OH)• that on annealing up to 180 K forms T(6OH)•. Through use of deuterium substitution at C5' and on the thymine base, i.e., specifically employing [5',5”-D,D]-5'-dThd, [5',5”-D,D]-5'-TMP, [CD3]-dThd and [CD3,6D]-dThd, we find unequivocal evidence for T(5OH)• formation and its conversion to T(6OH)•. The addition of OH− to the C5 position in T(−H)• and N3-Me-dThd•+ is governed by spin and charge localization. DFT calculations predict that the conversion of the “reducing” T(5OH)• to the “oxidizing” T(6OH)• occurs by a unimolecular OH group transfer from C5 to C6 in the thymine base. The T(5OH)• to T(6OH)• conversion is found to occur more readily for deprotonated dThd and its nucleotides than for N3-Me-dThd. In agreement, calculations predict that the deprotonated thymine base has a lower energy barrier (ca. 6 kcal/mol) for OH transfer than its corresponding N3-protonated thymine

  10. The effect of altering self-descriptive behavior on self-concept and classroom behavior.

    PubMed

    Lane, J; Muller, D

    1977-09-01

    This research examined the impact of operant reinforcement of positive self-descriptive behavior on the self-concepts and classroom behavior of 60 fifth-grade students. Three groups of 10 male and 10 female low self-concept students wrote a series of eight essays describing their school performance. The first group (P) received written reinforcement for positive self-descriptions of their school performance. The second group (G) received an equal number of reinforcements for general statements. The third group (C) received no reinforcement for written statements. Three areas of self-concept were measured with the Primary Self-Concept Inventory: personal-self, social-self, and intellectual-self. A frequency count was also made of nine classroom behaviors thought to be influenced by self-concept. The P group displayed increases in the frequency of positive self-descriptive statement and in intellectual self-concept but no changes in personal self-concept, social self-concept, or the nine classroom behaviors. The G and C groups showed no change in self-description, self-concept, or the nine classroom behaviors.

  11. TPS as an Effective Technique to Enhance the Students' Achievement on Writing Descriptive Text

    ERIC Educational Resources Information Center

    Sumarsih, M. Pd.; Sanjaya, Dedi

    2013-01-01

    Students' achievement in writing descriptive text is very low, in this study Think Pair Share (TPS) is applied to solve the problem. Action research is conducted for the result. Additionally, qualitative and quantitative techniques are applied in this research. The subject of this research is grade VIII in Junior High School in Indonesia. From…

  12. Corpus-based Grammar and the Heineken Effect: Lexico-grammatical Description for Language Learners.

    ERIC Educational Resources Information Center

    Owen, Charles

    1993-01-01

    The current status of corpus-based lexico-grammar is assessed. Particular reference is to the one substantial descriptive grammar of English to have made use of the new computational techniques, the Collins COBUILD English Grammar. (39 references) (Author/LB)

  13. The Effects of Auditory and Visual Stimuli on Tenth Graders' Descriptive Writing.

    ERIC Educational Resources Information Center

    Black, Janet

    A study investigated whether 10-grade English students would write more descriptively when their thinking was stimulated through viewing images, or hearing music, or both. Subjects, 49 students in 2 intact classrooms in a middle-class, suburban high school in the Jurupa School District, were randomly assigned to 1 of 4 groups that administered…

  14. Effects of Modeling Instruction on Descriptive Writing and Observational Skills in Middle School

    ERIC Educational Resources Information Center

    Park, Do-Yong; Logsdon, Cindy

    2015-01-01

    Before science can be completely understood, one of the fundamental skills that must be developed is observation. Improving descriptive writing and investigating students' observational skills in the classroom is the purpose of this study. The study was designed to determine if such skills, practiced through modeling activities, serve as a way to…

  15. Effects of Modeling Instruction on Descriptive Writing and Observational Skills in Middle School

    ERIC Educational Resources Information Center

    Park, Do-Yong; Logsdon, Cindy

    2015-01-01

    Before science can be completely understood, one of the fundamental skills that must be developed is observation. Improving descriptive writing and investigating students' observational skills in the classroom is the purpose of this study. The study was designed to determine if such skills, practiced through modeling activities, serve as a way to…

  16. A simple quasi-diabatization scheme suitable for spectroscopic problems based on one-electron properties of interacting states

    SciTech Connect

    Cave, Robert J.; Stanton, John F.

    2016-02-07

    We present a simple quasi-diabatization scheme applicable to spectroscopic studies that can be applied using any wavefunction for which one-electron properties and transition properties can be calculated. The method is based on rotation of a pair (or set) of adiabatic states to minimize the difference between the given transition property at a reference geometry of high symmetry (where the quasi-diabatic states and adiabatic states coincide) and points of lower symmetry where quasi-diabatic quantities are desired. Compared to other quasi-diabatization techniques, the method requires no special coding, facilitates direct comparison between quasi-diabatic quantities calculated using different types of wavefunctions, and is free of any selection of configurations in the definition of the quasi-diabatic states. On the other hand, the method appears to be sensitive to multi-state issues, unlike recent methods we have developed that use a configurational definition of quasi-diabatic states. Results are presented and compared with two other recently developed quasi-diabatization techniques.

  17. Noise-assisted energy transfer from the dilation of the set of one-electron reduced density matrices

    NASA Astrophysics Data System (ADS)

    Chakraborty, Romit; Mazziotti, David A.

    2017-05-01

    Noise-assisted energy transfer can be explained geometrically in terms of the set of one-electron reduced density matrices (1-RDMs) [R. Chakraborty and D. A. Mazziotti, Phys. Rev. A 91, 010101(R) (2015)]. In this paper, we examine the geometric picture of quantum noise for the seven-chromophore Fenna-Matthews-Olson (FMO) complex. Noise expands the feasible set of orbital occupation trajectories to the target state through the violation of the pure-state N-representability conditions on the 1-RDM, known as the generalized Pauli constraints. While the generalized Pauli constraints are not explicitly known for seven-electron systems, we are able to treat a seven-exciton model of the FMO complex through the use of generalized Pauli constraints for p qubits which are known for arbitrary p. In the model, we find that while dephasing noise alone produces a trajectory of ensemble states that neither expands the set of 1-RDMs nor reaches the reaction center, the inclusion of both dephasing and dissipation expands the set of 1-RDMs and exhibits an efficient energy transfer to the reaction center. The degree to which the noise expands the set of 1-RDMs, violating the generalized Pauli constraints, is quantified by the distance of the 1-RDM outside its pure set to the distance of the 1-RDM inside its ensemble set. The geometric picture of energy transfer has applications to general quantum systems in chemistry and physics.

  18. Nitric oxide reduction to ammonia by TiO₂ electrons in colloid solution via consecutive one-electron transfer steps.

    PubMed

    Goldstein, Sara; Behar, David; Rajh, Tijana; Rabani, Joseph

    2015-03-26

    The reaction mechanism of nitric oxide (NO) reduction by excess electrons on TiO2 nanoparticles (e(TiO2)(-)) has been studied under anaerobic conditions. TiO2 was loaded with 10-130 electrons per particle using γ-irradiation of acidic TiO2 colloid solutions containing 2-propanol. The study is based on time-resolved kinetics and reactants and products analysis. The reduction of NO by e(TiO2)(-) is interpreted in terms of competition between a reaction path leading to formation of NH3 and a path leading to N2O and N2. The proposed mechanism involves consecutive one-electron transfers of NO, and its reduction intermediates HNO, NH2O(•), and NH2OH. The results show that e(TiO2)(-) does not reduce N2O and N2. Second-order rate constants of e(TiO2)(-) reactions with NO (740 ± 30 M(-1) s(-1)) and NH2OH (270 ± 30 M(-1) s(-1)) have been determined employing the rapid-mixing stopped-flow technique and that with HNO (>1.3 × 10(6) M(-1) s(-1)) was derived from fitting the kinetic traces to the suggested reaction mechanism, which is discussed in detail.

  19. DNA sequence context as a determinant of the quantity and chemistry of guanine oxidation produced by hydroxyl radicals and one-electron oxidants.

    PubMed

    Margolin, Yelena; Shafirovich, Vladimir; Geacintov, Nicholas E; DeMott, Michael S; Dedon, Peter C

    2008-12-19

    DNA sequence context has emerged as a critical determinant of the location and quantity of nucleobase damage caused by many oxidizing agents. However, the complexity of nucleobase and 2-deoxyribose damage caused by strong oxidants such as ionizing radiation and the Fenton chemistry of Fe2+-EDTA/H2O2 poses a challenge to defining the location of nucleobase damage and the effects of sequence context on damage chemistry in DNA. To address this problem, we developed a gel-based method that allows quantification of nucleobase damage in oxidized DNA by exploiting Escherichia coli exonuclease III to remove fragments containing direct strand breaks and abasic sites. The rigor of the method was verified in studies of guanine oxidation by photooxidized riboflavin and nitrosoperoxycarbonate, for which different effects of sequence context have been demonstrated by other approaches (Margolin, Y., Cloutier, J. F., Shafirovich, V., Geacintov, N. E., and Dedon, P. C. (2006) Nat. Chem. Biol. 2, 365-366). Using duplex oligodeoxynucleotides containing all possible three-nucleotide sequence contexts for guanine, the method was used to assess the role of DNA sequence context in hydroxyl radical-induced guanine oxidation associated with gamma-radiation and Fe2+-EDTA/H2O2. The results revealed both differences and similarities for G oxidation by hydroxyl radicals and by one-electron oxidation by riboflavin-mediated photooxidation, which is consistent with the predominance of oxidation pathways for hydroxyl radicals other than one-electron oxidation to form guanine radical cations. Although the relative quantities of G oxidation produced by hydroxyl radicals were more weakly correlated with sequence-specific ionization potential than G oxidation produced by riboflavin, damage produced by both hydroxyl radical generators and riboflavin within two- and three-base runs of G showed biases in location that are consistent with a role for electron transfer in defining the location of the damage

  20. Solution Photophysics, One-Electron Photooxidation, and Photoinitiated Two-Electron Oxidation of Molybdenum(III) Complexes.

    PubMed

    Mohammed, Abdul K.; Isovitsch, Ralph A.; Maverick, Andrew W.

    1998-06-01

    Several six-coordinate Mo(III) complexes phosphoresce and undergo photooxidation in room-temperature solution. The phosphorescence of (Me(3)[9]aneN(3))MoX(3) (Me(3)[9]aneN(3) = 1,4,7-trimethyl-1,4,7-triazacyclononane) in CH(3)CN at room temperature occurs with the following maxima, lifetimes, and quantum yields: X = Cl, 1120 nm, 1.0 &mgr;s, and 6.1 x 10(-)(5); X = Br, 1130 nm, 0.80 &mgr;s, and 9.6 x 10(-)(5); and X = I, 1160 nm, 0.40 &mgr;s, and 1.2 x 10(-)(4), respectively. The phosphorescences are assigned to the {(2)E(g), (2)T(1g)} --> (4)A(2g) transition. Solutions of HB(Me(2)pz)(3)Mo(III)Cl(3)(-) Me(2)pzH = 3,5-dimethylpyrazole) in CH(3)CN, and solid MoCl(3)(py)(3) and (Me(3)[9]aneN(3))WCl(3), also phosphoresce. (Me(3)[9]aneN(3))MoX(3) (X = Cl, Br, I) complexes undergo reversible one-electron photooxidation upon irradiation in the presence of acceptors such as TCNE and chloranil. (Me(3)[9]aneN(3))MoX(3) (X = Br, I only) are photooxidized irreversibly to [(Me(3)[9]aneN(3))Mo(IV)X(3)](+) by C(NO(2))(4) in CH(3)CN. In CH(3)CN-H(2)O (1:1 v/v), photoinitiated two-electron oxidation occurs: the primary photoproduct is Mo(IV), which disproportionates spontaneously to form [(Me(3)[9]aneN(3))Mo(V)OX(2)](+).

  1. Pulse-radiolysis studies on the interaction of one-electron-reduced species with ascorbate oxidase in aqueous solution.

    PubMed Central

    O'Neill, P; Fielden, E M; Finazzi-Agrò, A; Avigliano, L

    1983-01-01

    The interaction of e-aq., CO2-. and one-electron reduced nitroaromatics (RNO2-.) with ascorbate oxidase (AAO) was studied in aqueous solution at pH 6.0 and 7.5 by using the technique of pulse radiolysis. From observations at 330, 410 and 610 nm, interaction of e-aq. and CO2-. with AAO results in non-specific reduction of the protein followed by reduction of Type 1 Cu in a rate-determining intramolecular step. Only a few per cent of the reducing equivalents ultimately results in reduction of Type 1 Cu. With large excesses of reducing equivalents (e-aq. and CO2-.) with respect to the copper concentration, the amount of Type 1 copper reduced never exceeds 50% of the total amount of Type 1 copper after a single radiation pulse. With less-powerful reducing agents, e.g. RNO2-. reduction of Type 1 Cu occurs via a bimolecular step, and there is no evidence for formation of radicals on protein residues. From observations at 330 nm it is evident that Type 2 and/or Type 3 Cu may also be reduced along with Type 1 Cu. Almost stoichiometric reduction of AAO by RNO2-. was observed, e.g. the protein accepts 6-7 reducing equivalents. It is inferred that the various types of redox couples Cu2+/Cu+ are in equilibrium and that intramolecular electron transfer between the different types of Cu is not rate-determining when using RNO2-. as reducing agent. PMID:6405732

  2. One-electron oxidation of an oxoiron(IV) complex to form an [O═FeV═NR]+ center.

    PubMed

    Van Heuvelen, Katherine M; Fiedler, Adam T; Shan, Xiaopeng; De Hont, Raymond F; Meier, Katlyn K; Bominaar, Emile L; Münck, Eckard; Que, Lawrence

    2012-07-24

    Oxoiron(V) species are postulated to be involved in the mechanisms of the arene cis-dihydroxylating Rieske dioxygenases and of bioinspired nonheme iron catalysts for alkane hydroxylation, olefin cis-dihydroxylation, and water oxidation. In an effort to obtain a synthetic oxoiron(V) complex, we report herein the one-electron oxidation of the S = 1 complex [Fe(IV)(O)(TMC)(NCCH(3))](2+) (1, where TMC is tetramethylcyclam) by treatment with tert -butyl hydroperoxide and strong base in acetonitrile to generate a metastable complex 2 at -44 °C, which has been characterized by UV-visible, resonance Raman, Mössbauer, and EPR methods. The defining spectroscopic characteristic of 2 is the unusual x/y anisotropy observed for the (57)Fe and (17)O A tensors associated with the high-valent Fe═O unit and for the (14)N A tensor of a ligand derived from acetonitrile. As shown by detailed density functional theory (DFT) calculations, the unusual x/y anisotropy observed can only arise from an iron center with substantially different spin populations in the d(xz) and d(yz) orbitals, which cannot correspond to an Fe(IV)═O unit but is fully consistent with an Fe(V) center, like that found for [Fe(V)(O)(TAML)](-) (where TAML is tetraamido macrocyclic ligand), the only well-characterized oxoiron(V) complex reported. Mass spectral analysis shows that the generation of 2 entails the addition of an oxygen atom to 1 and the loss of one positive charge. Taken together, the spectroscopic data and DFT calculations support the formulation of 2 as an iron(V) complex having axial oxo and acetylimido ligands, namely [Fe(V)(O)(TMC)(NC(O)CH(3))](+).

  3. One-electron oxidation of an oxoiron(IV) complex to form an [O═FeV═NR]+ center

    PubMed Central

    Van Heuvelen, Katherine M.; Fiedler, Adam T.; Shan, Xiaopeng; De Hont, Raymond F.; Meier, Katlyn K.; Bominaar, Emile L.; Münck, Eckard; Que, Lawrence

    2012-01-01

    Oxoiron(V) species are postulated to be involved in the mechanisms of the arene cis-dihydroxylating Rieske dioxygenases and of bioinspired nonheme iron catalysts for alkane hydroxylation, olefin cis-dihydroxylation, and water oxidation. In an effort to obtain a synthetic oxoiron(V) complex, we report herein the one-electron oxidation of the S = 1 complex [FeIV(O)(TMC)(NCCH3)]2+ (1, where TMC is tetramethylcyclam) by treatment with tert -butyl hydroperoxide and strong base in acetonitrile to generate a metastable complex 2 at -44 °C, which has been characterized by UV-visible, resonance Raman, Mössbauer, and EPR methods. The defining spectroscopic characteristic of 2 is the unusual x/y anisotropy observed for the 57Fe and 17O A tensors associated with the high-valent Fe═O unit and for the 14N A tensor of a ligand derived from acetonitrile. As shown by detailed density functional theory (DFT) calculations, the unusual x/y anisotropy observed can only arise from an iron center with substantially different spin populations in the dxz and dyz orbitals, which cannot correspond to an FeIV═O unit but is fully consistent with an FeV center, like that found for [FeV(O)(TAML)]- (where TAML is tetraamido macrocyclic ligand), the only well-characterized oxoiron(V) complex reported. Mass spectral analysis shows that the generation of 2 entails the addition of an oxygen atom to 1 and the loss of one positive charge. Taken together, the spectroscopic data and DFT calculations support the formulation of 2 as an iron(V) complex having axial oxo and acetylimido ligands, namely [FeV(O)(TMC)(NC(O)CH3)]+. PMID:22786933

  4. Descriptive thermodynamics

    NASA Astrophysics Data System (ADS)

    Ford, David; Huntsman, Steven

    2006-06-01

    Thermodynamics (in concert with its sister discipline, statistical physics) can be regarded as a data reduction scheme based on partitioning a total system into a subsystem and a bath that weakly interact with each other. Whereas conventionally, the systems investigated require this form of data reduction in order to facilitate prediction, a different problem also occurs, in the context of communication networks, markets, etc. Such “empirically accessible” systems typically overwhelm observers with the sort of information that in the case of (say) a gas is effectively unobtainable. What is required for such complex interacting systems is not prediction (this may be impossible when humans besides the observer are responsible for the interactions) but rather, description as a route to understanding. Still, the need for a thermodynamical data reduction scheme remains. In this paper, we show how an empirical temperature can be computed for finite, empirically accessible systems, and further outline how this construction allows the age-old science of thermodynamics to be fruitfully applied to them.

  5. Diffusion in a tube of varying cross section: Numerical study of reduction to effective one-dimensional description

    NASA Astrophysics Data System (ADS)

    Berezhkovskii, A. M.; Pustovoit, M. A.; Bezrukov, S. M.

    2007-04-01

    Brownian dynamics simulations of the particle diffusing in a long conical tube (the length of the tube is much greater than its smallest radius) are used to study reduction of the three-dimensional diffusion in tubes of varying cross section to an effective one-dimensional description. The authors find that the one-dimensional description in the form of the Fick-Jacobs equation with a position-dependent diffusion coefficient, D(x ), suggested by Zwanzig [J. Phys. Chem. 96, 3926 (1992)], with D(x ) given by the Reguera-Rubí formula [Phys. Rev. E 64, 061106 (2001)], D(x )=D/√1+R'(x)2, where D is the particle diffusion coefficient in the absence of constraints, and R(x ) is the tube radius at x, is valid when ∣R'(x)∣⩽1. When ∣R'(x)∣>1, higher spatial derivatives of the one-dimensional concentration in the effective diffusion equation cannot be neglected anymore as was indicated by Kalinay and Percus [J. Chem. Phys. 122, 204701 (2005)]. Thus the reduction to the effective one-dimensional description is a useful tool only when ∣R'(x)∣⩽1 since in this case one can apply the powerful standard methods to analyze the resulting diffusion equation.

  6. Descriptive statistics.

    PubMed

    Shi, Runhua; McLarty, Jerry W

    2009-10-01

    In this article, we introduced basic concepts of statistics, type of distributions, and descriptive statistics. A few examples were also provided. The basic concepts presented herein are only a fraction of the concepts related to descriptive statistics. Also, there are many commonly used distributions not presented herein, such as Poisson distributions for rare events and exponential distributions, F distributions, and logistic distributions. More information can be found in many statistics books and publications.

  7. π-Radical to σ-Radical Tautomerization in One-Electron-Oxidized 1-Methylcytosine and Its Analogs.

    PubMed

    Adhikary, Amitava; Kumar, Anil; Bishop, Casandra T; Wiegand, Tyler J; Hindi, Ragda M; Adhikary, Ananya; Sevilla, Michael D

    2015-09-03

    In this work, iminyl σ-radical formation in several one-electron-oxidized cytosine analogs, including 1-MeC, cidofovir, 2'-deoxycytidine (dCyd), and 2'-deoxycytidine 5'-monophosphate (5'-dCMP), were investigated in homogeneous, aqueous (D2O or H2O) glassy solutions at low temperatures by employing electron spin resonance (ESR) spectroscopy. Upon employing density functional theory (DFT) (DFT/B3LYP/6-31G* method), the calculated hyperfine coupling constant (HFCC) values of iminyl σ-radical agree quite well with the experimentally observed ones, thus confirming its assignment. ESR and DFT studies show that the cytosine iminyl σ-radical is a tautomer of the deprotonated cytosine π-cation radical [cytosine π-aminyl radical, C(N4-H)(•)]. Employing 1-MeC samples at various pHs ranging from ca. 8 to 11, ESR studies show that the tautomeric equilibrium between C(N4-H)(•) and the iminyl σ-radical at low temperature is too slow to be established without added base. ESR and DFT studies agree that, in the iminyl σ-radical, the unpaired spin is localized on the exocyclic nitrogen (N4) in an in-plane pure p-orbital. This gives rise to an anisotropic nitrogen hyperfine coupling (Azz = 40 G) from N4 and a near isotropic β-nitrogen coupling of 9.7 G from the cytosine ring nitrogen at N3. Iminyl σ-radical should exist in its N3-protonated form, as the N3-protonated iminyl σ-radical is stabilized in solution by over 30 kcal/mol (ΔG = -32 kcal/mol) over its conjugate base, the N3-deprotonated form. This is the first observation of an isotropic β-hyperfine ring nitrogen coupling in an N-centered DNA radical. Our theoretical calculations predict that the cytosine iminyl σ-radical can be formed in double-stranded DNA by a radiation-induced ionization-deprotonation process that is only 10 kcal/mol above the lowest energy path.

  8. The Mediating Role of Perceived Descriptive and Injunctive Norms in the Effects of Media Messages on Youth Smoking.

    PubMed

    Nan, Xiaoli; Zhao, Xiaoquan

    2016-01-01

    This research advances and tests a normative mediation model of media effects on youth smoking. The model predicts that exposure to various types of smoking-related media messages, including anti-smoking ads, cigarette ads, and smoking scenes in movies and television shows, exerts indirect effects on youth smoking intentions through the mediation of perceived descriptive and injunctive norms. Analysis of the data from the 3rd Legacy Media Tracking Survey offers general support for the proposed model with some unexpected findings, revealing a complex picture of media influence on youth smoking via normative and non-normative mechanisms. Theoretical and practical implications of the findings are discussed.

  9. Quantum Switching of Magnetic Fields by Circularly Polarized Re-Optimized π Laser Pulses: From One-Electron Atomic Ions to Molecules

    NASA Astrophysics Data System (ADS)

    Barth, Ingo; Manz, Jörn

    Circularly polarized re-optimized π laser pulses may induce electronic and/or nuclear ring currents in model systems, from one-electron atomic ions till molecules which should have three-, four-, or higher-fold axes of rotations or reflection-rotations, in order to support doubly or more degenerate, complex-valued eigenstates which support these ring currents. The ring currents in turn induce magnetic fields. The effects are about two orders of magnitude larger than for traditional ring currents which are induced by external magnetic fields. Moreover, the laser pulses allow to control the strengths and shapes of the ring currents and, therefore, also the induced magnetic fields. We present a survey of the development of the field, together with new quantum simulations which document ultrafast switchings of magnetic fields. We discuss various criteria such as strong ring currents with small radii, in order to generate huge magnetic fields, approaching 1,000T, in accord with the Biot-Savart law. Moreover, we consider various methods for monitoring the fields, and for applications, in particular ultrafast deflections of neutrons by means of quantum switching of the ring currents and induced magnetic fields.

  10. On the evolution of one-electron-oxidized deoxyguanosine in damaged DNA under physiological conditions: a DFT and ONIOM study on proton transfer and equilibrium.

    PubMed

    Galano, Annia; Alvarez-Idaboy, Juan Raúl

    2012-09-28

    Different deprotonation paths of the radical cation formed by one-electron oxidation of 2'-deoxyguanosine (2dG) sites in DNA have been studied using Density Functional Theory (M05-2X/6-31+G(d,p)) and ONIOM methodology (M05-2X/6-31+G(d,p):PM6) in conjunction with the SMD model to include the solvent effects. Models of increased complexity have been used ranging from the isolated nucleoside to a three unit double-stranded oligomer including the sugar units, the base pairing with cytidine, and the phosphate linkage. The reported results correspond to aqueous solution, at room temperature, and pH = 7.4. Under such conditions it was found that the proton transfer (PT) within the base pair is a minor path compared to the PT between the base pair and the surrounding water. It was also found that the deprotonation of ground-state 2dG˙(+) sites mainly yields C centered radicals in the sugar unit, with the largest populations corresponding to C4'˙ and C5'˙, followed by C3'˙. The different aspects of the presented theoretical study have been validated with experimental results.

  11. Communication: Satisfying fermionic statistics in the modeling of open time-dependent quantum systems with one-electron reduced density matrices

    SciTech Connect

    Head-Marsden, Kade; Mazziotti, David A.

    2015-02-07

    For an open, time-dependent quantum system, Lindblad derived the most general modification of the quantum Liouville equation in the Markovian approximation that models environmental effects while preserving the non-negativity of the system’s density matrix. While Lindblad’s modification is correct for N-electron density matrices, solution of the Liouville equation with a Lindblad operator causes the one-electron reduced density matrix (1-RDM) to violate the Pauli exclusion principle. Consequently, after a short time, the 1-RDM is not representable by an ensemble N-electron density matrix (not ensemble N-representable). In this communication, we derive the necessary and sufficient constraints on the Lindbladian matrix within the Lindblad operator to ensure that the 1-RDM remains N-representable for all time. The theory is illustrated by considering the relaxation of an excitation in several molecules F{sub 2}, N{sub 2}, CO, and BeH{sub 2} subject to environmental noise.

  12. Detection of Structural Changes upon One-Electron Oxidation and Reduction of Stilbene Derivatives by Time-Resolved Resonance Raman Spectroscopy during Pulse Radiolysis and Theoretical Calculations.

    PubMed

    Fujitsuka, Mamoru; Cho, Dae Won; Choi, Jungkweon; Tojo, Sachiko; Majima, Tetsuro

    2015-07-02

    Stilbene (St) derivatives have been investigated for many years because of their interesting photochemical reactions such as cis-trans isomerization in the excited states and charged states and their relation to poly(p-phenylenevinylene)s. To clarify their charged state properties, structural information is indispensable. In the present study, radical cations and radical anions of St derivatives were investigated by radiation chemical methods. Absorption spectra of radical ion states were obtained by transient absorption measurements during pulse radiolysis; theoretical calculations that included the solvent effect afforded reasonable assignments. The variation in the peak position was explained by using HOMO and LUMO energy levels. Structural changes upon one-electron oxidation and reduction were detected by time-resolved resonance Raman measurements during pulse radiolysis. Significant downshifts were observed with the CC stretching mode of the ethylenic groups, indicative of the decrease in the bonding order. It was confirmed that the downshifts observed with reduction were larger than those with oxidation. On the other hand, the downshift caused by oxidation depends significantly on the electron-donating or electron-withdrawing nature of the substituents.

  13. Towards an accurate description of perovskite ferroelectrics: exchange and correlation effects

    DOE PAGES

    Yuk, Simuck F.; Pitike, Krishna Chaitanya; Nakhmanson, Serge M.; ...

    2017-03-03

    Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy to the modified Perdew-Burke-Erzenhoff functional which was designed specifically for bulk solids (PBEsol). The relative performance of vdW-DF-C09 is strongly linked to the form of the exchange enhancement factor which, like PBEsol, tends to behave like the gradient expansion approximation for small reduced gradients. These results suggestmore » the general-purpose nature of the class of vdW-DF functionals, with particular consequences for predicting material functionality across dense and sparse matter regimes.« less

  14. Towards an accurate description of perovskite ferroelectrics: exchange and correlation effects

    PubMed Central

    Yuk, Simuck F.; Pitike, Krishna Chaitanya; Nakhmanson, Serge M.; Eisenbach, Markus; Li, Ying Wai; Cooper, Valentino R.

    2017-01-01

    Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy to the modified Perdew-Burke-Erzenhoff functional which was designed specifically for bulk solids (PBEsol). The relative performance of vdW-DF-C09 is strongly linked to the form of the exchange enhancement factor which, like PBEsol, tends to behave like the gradient expansion approximation for small reduced gradients. These results suggest the general-purpose nature of the class of vdW-DF functionals, with particular consequences for predicting material functionality across dense and sparse matter regimes. PMID:28256544

  15. Towards an accurate description of perovskite ferroelectrics: exchange and correlation effects

    NASA Astrophysics Data System (ADS)

    Yuk, Simuck F.; Pitike, Krishna Chaitanya; Nakhmanson, Serge M.; Eisenbach, Markus; Li, Ying Wai; Cooper, Valentino R.

    2017-03-01

    Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy to the modified Perdew-Burke-Erzenhoff functional which was designed specifically for bulk solids (PBEsol). The relative performance of vdW-DF-C09 is strongly linked to the form of the exchange enhancement factor which, like PBEsol, tends to behave like the gradient expansion approximation for small reduced gradients. These results suggest the general-purpose nature of the class of vdW-DF functionals, with particular consequences for predicting material functionality across dense and sparse matter regimes.

  16. Towards an accurate description of perovskite ferroelectrics: exchange and correlation effects.

    PubMed

    Yuk, Simuck F; Pitike, Krishna Chaitanya; Nakhmanson, Serge M; Eisenbach, Markus; Li, Ying Wai; Cooper, Valentino R

    2017-03-03

    Using the van der Waals density functional with C09 exchange (vdW-DF-C09), which has been applied to describing a wide range of dispersion-bound systems, we explore the physical properties of prototypical ABO3 bulk ferroelectric oxides. Surprisingly, vdW-DF-C09 provides a superior description of experimental values for lattice constants, polarization and bulk moduli, exhibiting similar accuracy to the modified Perdew-Burke-Erzenhoff functional which was designed specifically for bulk solids (PBEsol). The relative performance of vdW-DF-C09 is strongly linked to the form of the exchange enhancement factor which, like PBEsol, tends to behave like the gradient expansion approximation for small reduced gradients. These results suggest the general-purpose nature of the class of vdW-DF functionals, with particular consequences for predicting material functionality across dense and sparse matter regimes.

  17. Anaphoric Descriptions

    ERIC Educational Resources Information Center

    Beller, Charley

    2013-01-01

    The study of definite descriptions has been a central part of research in linguistics and philosophy of language since Russell's seminal work "On Denoting" (Russell 1905). In that work Russell quickly dispatches analyses of denoting expressions with forms like "no man," "some man," "a man," and "every…

  18. Anaphoric Descriptions

    ERIC Educational Resources Information Center

    Beller, Charley

    2013-01-01

    The study of definite descriptions has been a central part of research in linguistics and philosophy of language since Russell's seminal work "On Denoting" (Russell 1905). In that work Russell quickly dispatches analyses of denoting expressions with forms like "no man," "some man," "a man," and "every…

  19. Towards a more accurate microscopic description of the moving contact line problem - incorporating nonlocal effects through a statistical mechanics framework

    NASA Astrophysics Data System (ADS)

    Nold, Andreas; Goddard, Ben; Sibley, David; Kalliadasis, Serafim

    2014-03-01

    Multiscale effects play a predominant role in wetting phenomena such as the moving contact line. An accurate description is of paramount interest for a wide range of industrial applications, yet it is a matter of ongoing research, due to the difficulty of incorporating different physical effects in one model. Important small-scale phenomena are corrections to the attractive fluid-fluid and wall-fluid forces in inhomogeneous density distributions, which often previously have been accounted for by the disjoining pressure in an ad-hoc manner. We systematically derive a novel model for the description of a single-component liquid-vapor multiphase system which inherently incorporates these nonlocal effects. This derivation, which is inspired by statistical mechanics in the framework of colloidal density functional theory, is critically discussed with respect to its assumptions and restrictions. The model is then employed numerically to study a moving contact line of a liquid fluid displacing its vapor phase. We show how nonlocal physical effects are inherently incorporated by the model and describe how classical macroscopic results for the contact line motion are retrieved. We acknowledge financial support from ERC Advanced Grant No. 247031 and Imperial College through a DTG International Studentship.

  20. Unified description of potential profiles and electrical transport in unipolar and ambipolar organic field-effect transistors

    NASA Astrophysics Data System (ADS)

    Smits, Edsger C. P.; Mathijssen, Simon G. J.; Cölle, Michael; Mank, Arjan J. G.; Bobbert, Peter A.; Blom, Paul W. M.; de Boer, Bert; de Leeuw, Dago M.

    2007-09-01

    Validation of models for charge transport in organic transistors is fundamentally important for their technological use. Usually current-voltage measurements are performed to investigate organic transistors. In situ scanning Kelvin probe microscopy measurements provide a powerful complementary technique to distinguish between models based on band and hopping transports. We perform combined current-voltage and Kelvin probe microscopy measurements on unipolar and ambipolar organic field-effect transistors. We demonstrate that by this combination we can stringently test these two different transport models and come up with a unified description of charge transport in disordered organic semiconductors.

  1. Mean-Field Description of Ionic Size Effects with Non-Uniform Ionic Sizes: A Numerical Approach

    PubMed Central

    Zhou, Shenggao; Wang, Zhongming; Li, Bo

    2013-01-01

    Ionic size effects are significant in many biological systems. Mean-field descriptions of such effects can be efficient but also challenging. When ionic sizes are different, explicit formulas in such descriptions are not available for the dependence of the ionic concentrations on the electrostatic potential, i.e., there is no explicit, Boltzmann type distributions. This work begins with a variational formulation of the continuum electrostatics of an ionic solution with such non-uniform ionic sizes as well as multiple ionic valences. An augmented Lagrange multiplier method is then developed and implemented to numerically solve the underlying constrained optimization problem. The method is shown to be accurate and efficient, and is applied to ionic systems with non-uniform ionic sizes such as the sodium chloride solution. Extensive numerical tests demonstrate that the mean-field model and numerical method capture qualitatively some significant ionic size effects, particularly those for multivalent ionic solutions, such as the stratification of multivalent counterions near a charged surface. The ionic valence-to-volume ratio is found to be the key physical parameter in the stratification of concentrations. All these are not well described by the classical Poisson–Boltzmann theory, or the generalized Poisson–Boltzmann theory that treats uniform ionic sizes. Finally, various issues such as the close packing, limitation of the continuum model, and generalization of this work to molecular solvation are discussed. PMID:21929014

  2. [Descriptive statistics].

    PubMed

    Rendón-Macías, Mario Enrique; Villasís-Keever, Miguel Ángel; Miranda-Novales, María Guadalupe

    2016-01-01

    Descriptive statistics is the branch of statistics that gives recommendations on how to summarize clearly and simply research data in tables, figures, charts, or graphs. Before performing a descriptive analysis it is paramount to summarize its goal or goals, and to identify the measurement scales of the different variables recorded in the study. Tables or charts aim to provide timely information on the results of an investigation. The graphs show trends and can be histograms, pie charts, "box and whiskers" plots, line graphs, or scatter plots. Images serve as examples to reinforce concepts or facts. The choice of a chart, graph, or image must be based on the study objectives. Usually it is not recommended to use more than seven in an article, also depending on its length.

  3. Experimental Observation and Theoretical Description of the Pure Fano Effect in the Valence-Band Photoemission of Ferromagnets

    SciTech Connect

    Minar, J.; Ebert, H.; De Nadaie, C.; Brookes, N.B.; Venturini, F.; Ghiringhelli, G.; Chioncel, L.; Katsnelson, M. I.; Lichtenstein, A. I.

    2005-10-14

    The pure Fano effect in angle-integrated valence-band photoemission of ferromagnets has been observed for the first time. A contribution of the intrinsic spin polarization to the spin polarization of the photoelectrons has been avoided by an appropriate choice of the experimental parameters. The theoretical description of the resulting spectra reveals a complete analogy to the Fano effect observed before for paramagnetic transition metals. While the theoretical photocurrent and spin-difference spectra are found in good quantitative agreement with experiment in the case of Fe and Co, only a qualitative agreement could be achieved in the case of Ni by calculations on the basis of plain local spin-density approximation. Agreement with experimental data could be improved in this case in a very substantial way by a treatment of correlation effects on the basis of dynamical mean field theory.

  4. One-electron properties and electrostatic interaction energies from the expectation value expression and wave function of singles and doubles coupled cluster theory.

    PubMed

    Korona, Tatiana; Jeziorski, Bogumil

    2006-11-14

    One-electron density matrices resulting from the explicitly connected commutator expansion of the expectation value were implemented at the singles and doubles coupled cluster (CCSD) level. In the proposed approach the one-electron density matrix is obtained at a little extra cost in comparison to the calculation of the CCSD correlation energy. Therefore, in terms of the computational time the new method is significantly less demanding than the conventional linear-response CCSD theory which requires additionally an expensive calculation of the left-hand solution of the CCSD equations. The quality of the new density matrices was investigated by computing a set of one-electron properties for a series of molecules of varying sizes and comparing the results with data obtained using the full configuration interaction method or higher level coupled cluster theory. It has been found that the results obtained using the new approach are of the same quality as those predicted by the linear-response CCSD method. The novel one-electron density matrices have also been applied to study the energy of the electrostatic interaction for a number of van der Waals complexes, including the benzene and azulene dimers.

  5. Atomic level description of the protecting effect of osmolytes against thermal denaturation of proteins

    NASA Astrophysics Data System (ADS)

    Pieraccini, Stefano; Burgi, Luigi; Genoni, Alessandro; Benedusi, Anna; Sironi, Maurizio

    2007-04-01

    The protecting effect of the osmolyte molecule taurine against thermal denaturation of the protein Chimotripsin Inhibitor 2 was modelled using Molecular Dynamics simulations. The protein was simulated in denaturing conditions at different taurine concentrations. Analysis of the molecular details of its behaviour shows that the protective effect of the osmolyte is concentration dependent. Moreover, the influence of taurine on the solvent structure was studied. A concentration dependent ordering effect of taurine on water molecules emerges from solvent structure analysis and is well correlated to the protecting effect observed. Based on these observations an interpretation of the osmoprotective effect is proposed.

  6. Identification and Descriptions of the Momentum Effect in Studies of Learning: An Abstract Science Concept.

    ERIC Educational Resources Information Center

    Kwon, Jae-Sool; Mayer, Victor J.

    1985-01-01

    Several studies of the validity of the intensive time-series design have revealed a post-intervention increase in the level of achievement data (the "momentum effect"). Reports on the development and use of a technique to study the effect as it is observed in several data sets on the learning of plate tectonics. (Author/JN)

  7. A Hospital Management Course: Description and Evaluation of Its Effect on Attitudes toward Planning.

    ERIC Educational Resources Information Center

    Levchuk, John W.

    1981-01-01

    A course in hospital pharmacy management that focused on planning is described. The course had a positive effect on self-perceived ability but no effect on already positive student attitudes. Instructional objectives, lecture outline, evaluation criteria, and a synopsis of the questionnaire are appended. (Author/MLW)

  8. Assessing the applicability of the reduction to effective one-dimensional description of diffusion in a hemispherical shaped tube

    NASA Astrophysics Data System (ADS)

    Vázquez, Marco-Vinicio; Dagdug, Leonardo

    2010-12-01

    Computer simulations of the diffusion of a Brownian particle, in a hemispherical shaped tube, were carried out to assess the range of applicability of the reduction of the three-dimensional diffusion to an effective one-dimensional description. Previously Berezhkovskii et al. [21] founded that the one-dimensional description centered in the Fick-Jacobs' equation with a position dependent diffusion coefficients, D(x) (one due to R. Zwanzig [14], and another by Reguera-Rubí [15]), has a restricted range of applicability, for a conical tube. Remarkably, our results have shown that applying the Zwanzig's formula one can predict variation of τ in the whole range of a/R in n→w direction, while the Reguera-Rubí's formula fits simulations' data in the w→n direction. This is an important result since it is known that Reguera-Rubí's predicts better the mean first-passage time's behavior without regard of direction in other geometries, and this is our principal result.

  9. Failure to confirm the Rauscher and Shaw description of recovery of the Mozart effect.

    PubMed

    Steele, K M; Brown, J D; Stoecker, J A

    1999-06-01

    The Mozart effect is an increase in spatial reasoning scores detected immediately after listening to the first movement of a Mozart piano sonata. Rauscher and Shaw (1998) suggested that failure to produce a Mozart effect could arise from carryover effects of a spatial reasoning pretest which may interfere with the effect of listening to Mozart. They cited an unpublished study in which a verbal distractor was inserted between the pretest and listening condition, and the manipulation produced the recovery of a Mozart effect. This experiment attempted to confirm the unpublished study. 206 college students were exposed to one of three sequences, pretest-Verbal distractor material-Mozart, pretest-Mozart-Verbal distractor material, and pretest-Verbal distractor material. An immediate posttest indicated no significant difference on solution of paper folding and cutting items among the three groups. The results do not support Rauscher and Shaw (1998). Our negative results are consistent with prior failures in other laboratories to produce a Mozart effect.

  10. Unified description of solvent effects in the helix-coil transition

    NASA Astrophysics Data System (ADS)

    Badasyan, Artem; Tonoyan, Shushanik A.; Giacometti, Achille; Podgornik, Rudolf; Parsegian, V. Adrian; Mamasakhlisov, Yevgeni Sh.; Morozov, Vladimir F.

    2014-02-01

    We analyze the problem of the helix-coil transition in explicit solvents analytically by using spin-based models incorporating two different mechanisms of solvent action: explicit solvent action through the formation of solvent-polymer hydrogen bonds that can compete with the intrinsic intra-polymer hydrogen bonded configurations (competing interactions) and implicit solvent action, where the solvent-polymer interactions tune biopolymer configurations by changing the activity of the solvent (non-competing interactions). The overall spin Hamiltonian is comprised of three terms: the background in vacuo Hamiltonian of the "Generalized Model of Polypeptide Chain" type and two additive terms that account for the two above mechanisms of solvent action. We show that on this level the solvent degrees of freedom can be explicitly and exactly traced over, the ensuing effective partition function combining all the solvent effects in a unified framework. In this way we are able to address helix-coil transitions for polypeptides, proteins, and DNA, with different buffers and different external constraints. Our spin-based effective Hamiltonian is applicable for treatment of such diverse phenomena as cold denaturation, effects of osmotic pressure on the cold and warm denaturation, complicated temperature dependence of the hydrophobic effect as well as providing a conceptual base for understanding the behavior of intrinsically disordered proteins and their analogues.

  11. Effects of sensory augmentation on postural control and gait symmetry of transfemoral amputees: a case description.

    PubMed

    Pagel, Anna; Arieta, Alejandro Hernandez; Riener, Robert; Vallery, Heike

    2016-10-01

    Despite recent advances in leg prosthetics, transfemoral amputees still experience limitations in postural control and gait symmetry. It has been hypothesized that artificial sensory information might improve the integration of the prosthesis into the human sensory-motor control loops and, thus, reduce these limitations. In three transfemoral amputees, we investigated the effect of Electrotactile Moving Sensation for Sensory Augmentation (EMSSA) without training and present preliminary findings. Experimental conditions included standing with open/closed eyes on stable/unstable ground as well as treadmill walking. For standing conditions, spatiotemporal posturographic measures and sample entropy were derived from the center of pressure. For walking conditions, step length and stance duration were calculated. Conditions without feedback showed effects congruent with findings in the literature, e.g., asymmetric weight bearing and step length, and validated the collected data. During standing, with EMSSA a tendency to influence postural control in a negative way was found: Postural control was less effective and less efficient and the prosthetic leg was less involved. Sample entropy tended to decrease, suggesting that EMSSA demanded increased attention. During walking, with EMSSA no persistent positive effect was found. This contrasts the positive subjective assessment and the positive effect on one subject's step length.

  12. Anti-inflammatory and Antioxidant Effects of Sesame Oil on Atherosclerosis: A Descriptive Literature Review

    PubMed Central

    Parthasarathy, Sam

    2017-01-01

    Sesame oil (SO) is a supplement that has been known to have anti-inflammatory and antioxidant properties, which makes it effective for reducing atherosclerosis and the risk of cardiovascular disease. Due to the side effects of statins, the current recommended treatment for atherosclerosis and cardiovascular diseases, the idea of using dietary and nutritional supplementation has been explored. The benefits of a dietary health regime have piqued curiosity because many different cultures have reaped health benefits through the ingredients in their cooking with negligible side effects. The purpose of this literary review is to provide a broad overview of the potential benefits and risks of SO on the development of atherosclerosis and its direction toward human clinical use. Current in vivo and in vitro research has shed light on the effects of SO and its research has shown that SO can decrease low-density lipoprotein (LDL) levels while maintaining high-density lipoprotein (HDL) levels. Current limitations in recent studies include no standardized doses of SO given to subjects and unknown specific mechanisms of the different components of SO. Future studies should explore possible synergistic and adverse effects of SO when combined with current recommended pharmaceutical therapies and other adjunct treatments. PMID:28924525

  13. Cross-Talk in the ACS WFC Detectors. I: Description of the Effect

    NASA Astrophysics Data System (ADS)

    Biavalisco, Mauro

    2004-08-01

    Images acquired with the Wide Field Channel (WFC) of the Advanced Camera for Surveys (ACS) are affected by cross talk between the four CCD quadrants that correspond to the four amplifiers of the detector array. The effect is observed as (mostly) negative ghost images generated by relatively bright sources located in adjacent quadrants. Their position in the quadrant is mirror-symmetric relative to the positions of the generating sources. The strength of the cross talk is small, i.e. the ghost images have apparent surface brightness of only a few electrons per pixel, and it appears to be mostly a cosmetic problem, with little measurable effects on the photometry of affected sources. Here we describe the phenomenology of the cross talk, and in a companion ISR (Giavalisco 2004) we suggest an observing strategy to minimize its effects on the images.

  14. Quantum fluctuations and isotope effects in ab initio descriptions of water

    SciTech Connect

    Wang, Lu; Markland, Thomas E.; Ceriotti, Michele

    2014-09-14

    Isotope substitution is extensively used to investigate the microscopic behavior of hydrogen bonded systems such as liquid water. The changes in structure and stability of these systems upon isotope substitution arise entirely from the quantum mechanical nature of the nuclei. Here, we provide a fully ab initio determination of the isotope exchange free energy and fractionation ratio of hydrogen and deuterium in water treating exactly nuclear quantum effects and explicitly modeling the quantum nature of the electrons. This allows us to assess how quantum effects in water manifest as isotope effects, and unravel how the interplay between electronic exchange and correlation and nuclear quantum fluctuations determine the structure of the hydrogen bond in water.

  15. Quantum fluctuations and isotope effects in ab initio descriptions of water.

    PubMed

    Wang, Lu; Ceriotti, Michele; Markland, Thomas E

    2014-09-14

    Isotope substitution is extensively used to investigate the microscopic behavior of hydrogen bonded systems such as liquid water. The changes in structure and stability of these systems upon isotope substitution arise entirely from the quantum mechanical nature of the nuclei. Here, we provide a fully ab initio determination of the isotope exchange free energy and fractionation ratio of hydrogen and deuterium in water treating exactly nuclear quantum effects and explicitly modeling the quantum nature of the electrons. This allows us to assess how quantum effects in water manifest as isotope effects, and unravel how the interplay between electronic exchange and correlation and nuclear quantum fluctuations determine the structure of the hydrogen bond in water.

  16. Description of load interaction effects by the {Delta}K{sub eff} concept

    SciTech Connect

    Lang, M.

    1999-07-01

    An experimental study of load interaction effects in Al 7475-T7351 is presented. The crack propagation stress intensity factor, K{sub PR}, was determined after different overload sequences, also involving subsequent compression loading. The results of these experiments demonstrate that the single overhead can be described by a single function, which describes the unloading process after the overload. One main conclusion is that load interaction effects are governed by residual compressive stresses in front of the crack tip, while crack closure plays a minor role.

  17. Promoting Inclusion? "Inclusive" and Effective Head Teachers' Descriptions of Their Work

    ERIC Educational Resources Information Center

    Lindqvist, Gunilla; Nilholm, Claes

    2014-01-01

    The purpose of the reported interview study from Sweden is to contribute to our understanding of how head teachers can promote inclusive practices. Five head teachers were selected from a larger sample of head teachers working in compulsory schools (6-16) according to specific criteria in order to obtain head teachers who work effectively and…

  18. Non-singular bounce scenarios in loop quantum cosmology and the effective field description

    SciTech Connect

    Cai, Yi-Fu; Wilson-Ewing, Edward E-mail: wilson-ewing@phys.lsu.edu

    2014-03-01

    A non-singular bouncing cosmology is generically obtained in loop quantum cosmology due to non-perturbative quantum gravity effects. A similar picture can be achieved in standard general relativity in the presence of a scalar field with a non-standard kinetic term such that at high energy densities the field evolves into a ghost condensate and causes a non-singular bounce. During the bouncing phase, the perturbations can be stabilized by introducing a Horndeski operator. Taking the matter content to be a dust field and an ekpyrotic scalar field, we compare the dynamics in loop quantum cosmology and in a non-singular bouncing effective field model with a non-standard kinetic term at both the background and perturbative levels. We find that these two settings share many important properties, including the result that they both generate scale-invariant scalar perturbations. This shows that some quantum gravity effects of the very early universe may be mimicked by effective field models.

  19. The Effect of Critical Thinking Instruction on Verbal Descriptions of Music

    ERIC Educational Resources Information Center

    Johnson, Daniel C.

    2011-01-01

    The purpose of this study was to determine the effect of critical thinking instruction on music listening skills of fifth-grade students as measured by written responses to music listening. The researcher compared instruction that included opportunities for critical thinking (Critical Thinking Instruction, CTI) with parallel instruction without…

  20. Modeling fuels and fire effects in 3D: Model description and applications

    Treesearch

    Francois Pimont; Russell Parsons; Eric Rigolot; Francois de Coligny; Jean-Luc Dupuy; Philippe Dreyfus; Rodman R. Linn

    2016-01-01

    Scientists and managers critically need ways to assess how fuel treatments alter fire behavior, yet few tools currently exist for this purpose.We present a spatially-explicit-fuel-modeling system, FuelManager, which models fuels, vegetation growth, fire behavior (using a physics-based model, FIRETEC), and fire effects. FuelManager's flexible approach facilitates...

  1. Effects of freezing-thawing on sensory descriptive profiles of cooked poultry breast meat

    USDA-ARS?s Scientific Manuscript database

    Freezing is a common method used by consumers to extend meat shelf life and by researchers to allow for subsequent meat quality assessments and processing. However, the effects of freezing on the sensory quality of cooked poultry breast meat are not well documented. The objective of this study was t...

  2. Writing Simple Sentences and Descriptive Paragraphs: Effects of an Intervention on Adolescents with Writing Difficulties

    ERIC Educational Resources Information Center

    Datchuk, Shawn M.

    2016-01-01

    The present study investigated the effects of a multicomponent intervention on the writing behavior of adolescents with writing difficulties. A single-case design consisting of a combination of multiple-probe design across participants and pre-post test was used. Four participants completed two intervention phases: (a) sentence instruction and…

  3. SPELT (Strategies Program for Effective Learning/Thinking): A Description and Analysis of Instructional Procedures.

    ERIC Educational Resources Information Center

    Peat, D.; And Others

    1989-01-01

    Describes an instructional model, Strategies Program for Effective Learning/Thinking (SPELT), that was developed to translate cognitive psychological theory and research into a practical instructional program. The extent to which SPELT conforms to current instructional design principles is examined, and macro versus micro instructional sequencing…

  4. Effective one-component description of two-component Bose-Einstein condensate dynamics

    SciTech Connect

    Dutton, Zachary; Clark, Charles W.

    2005-06-15

    We investigate dynamics in two-component Bose-Einstein condensates in the context of coupled Gross-Pitaevskii equations and derive results for the evolution of the total density fluctuations. Using these results, we show how, in many cases of interest, the dynamics can be accurately described with an effective one-component Gross-Pitaevskii equation for one of the components, with the trap and interaction coefficients determined by the relative differences in the scattering lengths. We discuss the model in various regimes, where it predicts breathing excitations, and the formation of vector solitons. An effective nonlinear evolution is predicted for some cases of current experimental interest. We then apply the model to construct quasistationary states of two-component condensates.

  5. Whack-A-Mole Model: Towards a Unified Description of Biological Effects Caused by Radiation Exposure

    NASA Astrophysics Data System (ADS)

    Manabe, Yuichiro; Wada, Takahiro; Tsunoyama, Yuichi; Nakajima, Hiroo; Nakamura, Issei; Bando, Masako

    2015-04-01

    We present a novel model to for estimating biological effects caused by artificial radiation exposure, i.e., the Whack-A-Mole (WAM) model. It is important to take into account the recovery effects during the time course of cellular reactions. The inclusion of dose-rate dependence is essential in the risk estimation of low-dose radiation, while nearly all the existing theoretical models rely on the total dose dependence only. By analyzing experimental data of the relationship between the radiation dose and the induced mutation frequency of five organisms, namely, mouse, Drosophila, chrysanthemum, maize, Tradescantia, we found that all the data can be reproduced by the WAM model. Most remarkably, a scaling function, which is derived from the WAM model, consistently accounts for the observed mutation frequencies of the five organisms. This is the first rationale to account for the dose rate dependence as well as to provide a unified understanding of a general feature of organisms.

  6. Effective low-energy description of almost Ising-Heisenberg diamond chain

    NASA Astrophysics Data System (ADS)

    Derzhko, Oleg; Krupnitska, Olesia; Lisnyi, Bohdan; Strečka, Jozef

    2015-11-01

    We consider a geometrically frustrated spin-(1/2) Ising-Heisenberg diamond chain, which is an exactly solvable model when assuming part of the exchange interactions as Heisenberg ones and another part as Ising ones. A small XY part is afterwards perturbatively added to the Ising couplings, which enabled us to derive an effective Hamiltonian describing the low-energy behavior of the modified but full quantum version of the initial model. The effective model is much simpler and free of frustration. It is shown that the XY part added to the originally Ising interaction gives rise to the spin-liquid phase with continuously varying magnetization, which emerges between the magnetization plateaus and is totally absent in the initial hybrid diamond-chain model. The elaborated approach can also be applied to other hybrid Ising-Heisenberg spin systems.

  7. Effective one-dimensional description of confined diffusion biased by a transverse gravitational force.

    PubMed

    Kalinay, Pavol

    2011-07-01

    Diffusion of pointlike noninteracting particles in a two-dimensional channel of varying cross section is considered. The particles are biased by a constant force in the transverse direction. A recurrence mapping procedure is applied, which enables the derivation of an effective one-dimensional (1D) evolution equation that governs the 1D density of the particles in the channel. In the limit of stationary flow, an extended Fick-Jacobs equation is reached, which is corrected by an effective diffusion coefficient D(x) that depends on the longitudinal coordinate x. The result is an approximate formula for D(x) that also involves the influence of the transverse force. The calculations are verified by the stationary diffusion in a linear cone, which is exactly solvable.

  8. One electron oxidation potential as a predictor of rate constants of N-containing compounds with carbonate radical and triplet excited state organic matter.

    PubMed

    Arnold, William A

    2014-04-01

    Photo-generated transient species, such as the carbonate radical and triplet excited state natural organic matter, mediate the oxidation of pollutants in various sunlit or artificially irradiated systems. In this work, one-electron oxidation potentials for 70 nitrogen-containing compounds were computed, and literature data were used to develop quantitative structure-activity relationships (QSARs) for prediction of the second order reaction rate constants with these two oxidants. For carbonate radical, separate QSARs were necessary for compounds with and without resonance stabilization of the resulting radical, and predicted rate constants were, on average, within a factor of three of experimental values. With the limited data set available, results suggest that one-electron oxidation potential is also a viable descriptor variable for predictions of rate constants with triplet excited states.

  9. An effective description of dark matter and dark energy in the mildly non-linear regime

    DOE PAGES

    Lewandowski, Matthew; Maleknejad, Azadeh; Senatore, Leonardo

    2017-05-18

    In the next few years, we are going to probe the low-redshift universe with unprecedented accuracy. Among the various fruits that this will bear, it will greatly improve our knowledge of the dynamics of dark energy, though for this there is a strong theoretical preference for a cosmological constant. We assume that dark energy is described by the so-called Effective Field Theory of Dark Energy, which assumes that dark energy is the Goldstone boson of time translations. Such a formalism makes it easy to ensure that our signatures are consistent with well-established principles of physics. Since most of the informationmore » resides at high wavenumbers, it is important to be able to make predictions at the highest wavenumber that is possible. Furthermore, the Effective Field Theory of Large-Scale Structure (EFTofLSS) is a theoretical framework that has allowed us to make accurate predictions in the mildly non-linear regime. In this paper, we derive the non-linear equations that extend the EFTofLSS to include the effect of dark energy both on the matter fields and on the biased tracers. For the specific case of clustering quintessence, we then perturbatively solve to cubic order the resulting non-linear equations and construct the one-loop power spectrum of the total density contrast.« less

  10. Systematic description of the effect of particle shape on the strength properties of granular media

    NASA Astrophysics Data System (ADS)

    Azéma, Emilien; Estrada, Nicolas; Preechawuttipong, Itthichai; Delenne, Jean-Yves; Radjai, Farhang

    2017-06-01

    In this paper, we explore numerically the effect of particle shape on the mechanical behavior of sheared granular packings. In the framework of the Contact Dynamic (CD)Method, we model angular shape as irregular polyhedral particles, non-convex shape as regular aggregates of four overlapping spheres, elongated shape as rounded cap rectangles and platy shape as square-plates. Binary granular mixture consisting of disks and elongated particles are also considered. For each above situations, the number of face of polyhedral particles, the overlap of spheres, the aspect ratio of elongated and platy particles, are systematically varied from spheres to very angular, non-convex, elongated and platy shapes. The level of homogeneity of binary mixture varies from homogenous packing to fully segregated packings. Our numerical results suggest that the effects of shape parameters are nonlinear and counterintuitive. We show that the shear strength increases as shape deviate from spherical shape. But, for angular shapes it first increases up to a maximum value and then saturates to a constant value as the particles become more angular. For mixture of two shapes, the strength increases with respect of the increase of the proportion of elongated particles, but surprisingly it is independent with the level of homogeneity of the mixture. A detailed analysis of the contact network topology, evidence that various contact types contribute differently to stress transmission at the micro-scale.

  11. [The narghile and its effects on health. Part I: the narghile, general description and properties].

    PubMed

    Ben Saad, H

    2009-12-01

    A narghile is a water-pipe used to smoke a tobacco preparation. As the smoker inhales, the tobacco smoke is sucked down from the bowl and then bubbles up through the water into the air of the smoke chamber and then through the hose to the smoker. Its origins are mysterious and controversial. Nevertheless it remains, under different names, an object used regularly by more than one hundred million people in the world. Since the eighties and especially nineties, its consumption has grown significantly and is now considered to be a worldwide epidemic. However, the knowledge about the effects of narghile smoke on health is partial and sometimes contradictory. Indeed, we are witnessing increasing confusion in biomedical studies and scientific debate about its health impact is unresolved. Given this situation, revealing a serious and profound lack of information about the real nature and toxicity of hookah smoke, the authors conducted this two-part study. The first part presents epidemiological data, describes the narghile and the different types of narghile tobacco and exposes the composition of narghile smoke. The second part highlights the lack of reliable data about the detrimental effects of the narghile pipe on health and especially on the cardiopulmonary function.

  12. Precise analytical description of the Earth matter effect on oscillations of low energy neutrinos

    SciTech Connect

    Ioannisian, A.N.; Kazarian, N.A.; Smirnov, A.Yu.; Wyler, D.

    2005-02-01

    We present a formalism for the matter effects in the Earth on low energy neutrino fluxes which is both accurate and has all the advantages of a full analytic treatment. The oscillation probabilities are calculated up to the second order term in {epsilon}(x){identical_to}2V(x)E/{delta}m{sup 2}, where V(x) is the neutrino potential at position x. We show the absence of large undamped phases which makes the expansion in {epsilon} well behaved. An improved expansion is presented in terms of the variation of V(x) around a suitable mean value which allows one to treat energies up to those relevant for supernova neutrinos. We discuss also the case of three-neutrino mixing.

  13. Case Report of Posterior Crossbite: Description of an Effective Treatment Protocol.

    PubMed

    Rogério de Mendonça, Marcos; Gonçales Verri, Ana Caroline; Pimenta Martins, Lídia; Aparecido Cuoghi, Osmar

    2016-09-01

    Early treatment of functional unilateral posterior crossbite during the mixed dentition stage is extremely important, as it provides the correct positioning of osseous bases, teeth, and the temporomandibular joint when the stomatognathic system is in growth and development. This article reports on a 9-year-old patient who presented with functional unilateral posterior crossbite and was treated with a modified Hyrax expander. The case report highlights a simple, low-cost, effective treatment protocol. The malocclusion was corrected with 15 days of active use of the appliance, 5 months of use for retention purposes, and 5 years of post-treatment follow-up. The stability in the long-term treatment is highly dependent on early diagnosis by the clinician and the elimination of the etiological factor through use of the proper appliance.

  14. Uniform analytic description of dephasing effects in two-state transitions

    SciTech Connect

    Lacour, X.; Guerin, S.; Jauslin, H. R.; Yatsenko, L. P.; Vitanov, N. V.

    2007-03-15

    We describe the effect of pure dephasing upon the time-dependent dynamics of two-state quantum systems in the framework of a Lindblad equation for the time evolution of the density matrix. A uniform approximate formula is derived, which modifies the corresponding lossless transition probability by an exponential factor containing the dephasing rate and the interaction parameters. This formula is asymptotically exact in both the diabatic and adiabatic limits; comparison with numerical results shows that it is highly accurate also in the intermediate range. Several two-state models are considered in more detail, including the Landau-Zener, Rosen-Zener, Allen-Eberly, and Demkov-Kunike models, along with several other models, such as a Gaussian model and a Landau-Zener model with a pulsed coupling.

  15. Applicability of the Fokker-Planck equation to the description of diffusion effects on nucleation

    NASA Astrophysics Data System (ADS)

    Sorokin, M. V.; Dubinko, V. I.; Borodin, V. A.

    2017-01-01

    The nucleation of islands in a supersaturated solution of surface adatoms is considered taking into account the possibility of diffusion profile formation in the island vicinity. It is shown that the treatment of diffusion-controlled cluster growth in terms of the Fokker-Planck equation is justified only provided certain restrictions are satisfied. First of all, the standard requirement that diffusion profiles of adatoms quickly adjust themselves to the actual island sizes (adiabatic principle) can be realized only for sufficiently high island concentration. The adiabatic principle is essential for the probabilities of adatom attachment to and detachment from island edges to be independent of the adatom diffusion profile establishment kinetics, justifying the island nucleation treatment as the Markovian stochastic process. Second, it is shown that the commonly used definition of the "diffusion" coefficient in the Fokker-Planck equation in terms of adatom attachment and detachment rates is justified only provided the attachment and detachment are statistically independent, which is generally not the case for the diffusion-limited growth of islands. We suggest a particular way to define the attachment and detachment rates that allows us to satisfy this requirement as well. When applied to the problem of surface island nucleation, our treatment predicts the steady-state nucleation barrier, which coincides with the conventional thermodynamic expression, even though no thermodynamic equilibrium is assumed and the adatom diffusion is treated explicitly. The effect of adatom diffusional profiles on the nucleation rate preexponential factor is also discussed. Monte Carlo simulation is employed to analyze the applicability domain of the Fokker-Planck equation and the diffusion effect beyond it. It is demonstrated that a diffusional cloud is slowing down the nucleation process for a given monomer interaction with the nucleus edge.

  16. Effectiveness of local support for the adoption of a national programme--a descriptive study.

    PubMed

    Pearce, Christopher; Bartlett, Jenny; Mcleod, Adam; Eustace, Paula; Amos, Rod; Shearer, Marianne

    2014-01-01

    Change management in health care is a complex and time-consuming endeavour, and no less so in implementing technological systems. In deploying a nationwide programme, the personally controlled electronic health record (PCEHR), the Australian Government employed a number of national and local change management programmes. This article describes the processes undertaken and the experiences of introducing the PCEHR into 74 general practices across a specific area of metropolitan Melbourne. An online survey was developed by an independent evaluator and offered to all participating practices. The response rate was 82%. The deployment and testing of the eHealth infrastructure and the roll-out of the PCEHR were deeply supported through face-to-face, locally contextualised support processes. The area Medicare Local (ML), an organisation that provides support services to general practice and allied health in the community, provided support and programme coordination. This support occurred in the environment of a number of other initiatives to improve adoption. The impact and value of this support in the registration and adoption process was explored in an online survey and found to be the key factor in practice engagement and success. ML support was seen as instrumental in improving adoption and was more effective than other activities. This article highlights the role of local support, in this case, MLs, in the effective implementation of eHealth programmes across a range of stakeholder groups, in particular, general practice, and the potential for the lessons learned from the engagement model of such an entity to be more generally applied.

  17. Large-deviation principles, stochastic effective actions, path entropies, and the structure and meaning of thermodynamic descriptions

    NASA Astrophysics Data System (ADS)

    Smith, Eric

    2011-04-01

    The meaning of thermodynamic descriptions is found in large-deviations scaling (Ellis 1985 Entropy, Large Deviations, and Statistical Mechanics (New York: Springer); Touchette 2009 Phys. Rep. 478 1-69) of the probabilities for fluctuations of averaged quantities. The central function expressing large-deviations scaling is the entropy, which is the basis both for fluctuation theorems and for characterizing the thermodynamic interactions of systems. Freidlin-Wentzell theory (Freidlin and Wentzell 1998 Random Perturbations in Dynamical Systems 2nd edn (New York: Springer)) provides a quite general formulation of large-deviations scaling for non-equilibrium stochastic processes, through a remarkable representation in terms of a Hamiltonian dynamical system. A number of related methods now exist to construct the Freidlin-Wentzell Hamiltonian for many kinds of stochastic processes; one method due to Doi (1976 J. Phys. A: Math. Gen. 9 1465-78 1976 J. Phys. A: Math. Gen. 9 1479) and Peliti (1985 J. Physique 46 1469; 1986 J. Phys. A: Math. Gen. 19 L365, appropriate to integer counting statistics, is widely used in reaction-diffusion theory. Using these tools together with a path-entropy method due to Jaynes (1980 Annu. Rev. Phys. Chem. 31 579-601), this review shows how to construct entropy functions that both express large-deviations scaling of fluctuations, and describe system-environment interactions, for discrete stochastic processes either at or away from equilibrium. A collection of variational methods familiar within quantum field theory, but less commonly applied to the Doi-Peliti construction, is used to define a 'stochastic effective action', which is the large-deviations rate function for arbitrary non-equilibrium paths. We show how common principles of entropy maximization, applied to different ensembles of states or of histories, lead to different entropy functions and different sets of thermodynamic state variables. Yet the relations among all these levels of

  18. Fourier-Legendre expansion of the one-electron density matrix of ground-state two-electron atoms

    NASA Astrophysics Data System (ADS)

    Ragot, Sébastien; Ruiz, María Belén

    2008-09-01

    The density matrix ρ(r,r') of a spherically symmetric system can be expanded as a Fourier-Legendre series of Legendre polynomials Pl(cosθ=rṡr'/rr'). Application is here made to harmonically trapped electron pairs (i.e., Moshinsky's and Hooke's atoms), for which exact wavefunctions are known, and to the helium atom, using a near-exact wavefunction. In the present approach, generic closed form expressions are derived for the series coefficients of ρ(r,r'). The series expansions are shown to converge rapidly in each case, with respect to both the electron number and the kinetic energy. In practice, a two-term expansion accounts for most of the correlation effects, so that the correlated density matrices of the atoms at issue are essentially a linear functions of Pl(cosθ)=cosθ. For example, in the case of Hooke's atom, a two-term expansion takes in 99.9% of the electrons and 99.6% of the kinetic energy. The correlated density matrices obtained are finally compared to their determinantal counterparts, using a simplified representation of the density matrix ρ(r,r'), suggested by the Legendre expansion. Interestingly, two-particle correlation is shown to impact the angular delocalization of each electron, in the one-particle space spanned by the r and r' variables.

  19. Effectiveness of a MP-blocking splint and therapy in rheumatoid arthritis: a descriptive pilot study.

    PubMed

    Formsma, S A; van der Sluis, C K; Dijkstra, P U

    2008-01-01

    The purpose was to evaluate the effect of a metacarpal phalangeal joint blocking splint combined with exercises, aimed at regaining strength, manipulative skills, and a normal pattern of movement of the hands in patients with rheumatoid arthritis (RA). All patients were measured three times: before the start of the therapy, after finishing the therapy, and at three months follow-up. Outcome measures were grip strength, pinch strength (Jamar dynamometer and pinchmeter), active range of motion (goniometer), dexterity (Sequential Occupational Dexterity Assessment [SODA]), and experienced functioning in daily life (Michigan Hand Outcome Questionnaire and Disability of Arm, Shoulder, and Hand questionnaire). The hands treated improved significantly on both total SODA score and on the pain score of the SODA. This means that the dexterity improved over time. No significant changes were found on the other outcome measures. This study indicates that intervention on the function of the hands in patients with RA who present an intrinsic-plus posture and movement pattern, improve significantly on dexterity and pain, measured by the SODA.

  20. Closed flux tubes in D = 2 + 1 SU( N ) gauge theories: dynamics and effective string description

    NASA Astrophysics Data System (ADS)

    Athenodorou, Andreas; Teper, Michael

    2016-10-01

    We extend our earlier calculations of the spectrum of closed flux tubes in SU( N ) gauge theories in 2 + 1 dimensions, with a focus on questions raised by recent theoretical progress on the effective string action of long flux tubes and the world-sheet action for flux tubes of moderate lengths. Our new calculations in SU(4) and SU(8) provide evidence that the leading O(1 /l γ ) non-universal correction to the flux tube ground state energy does indeed have a power γ ≥ 7. We perform a study in SU(2), where we can traverse the length at which the Nambu-Goto ground state becomes tachyonic, to obtain an all- N view of the spectrum. Our comparison of the k = 2 flux tube excitation energies in SU(4) and SU(6) suggests that the massive world sheet excitation associated with the k = 2 binding has a scale that knows about the group and hence the theory in the bulk, and we comment on the potential implications of world sheet massive modes for the bulk spectrum. We provide a quantitative analysis of the surprising (near-)orthogonality of flux tubes carrying flux in different SU( N ) representations, which implies that their screening by gluons is highly suppressed even at small N.

  1. Effects of Personality Disorders on Self-Other Agreement and Favorableness in Personality Descriptions.

    PubMed

    Tandler, Nancy; Mosch, Alice; Wolf, Annegret; Borkenau, Peter

    2016-10-01

    The authors studied effects of self-reported personality disorder (PD) symptoms on interpersonal perception, particularly self-other agreement and favorableness. Using a round-robin design, 52 groups of four well-acquainted students described themselves and each other on a measure of the Five-Factor model of personality and were administered a self-report screening instrument for DSM-IV (Axis 2). Using the Social Accuracy Model, the peer reports were predicted, across items, from either (a) the target person's self-reports plus the self-report item means, or (b) the items' social desirability. This resulted in separate coefficients for each peer-target dyad, indicating either self-other agreement or favorableness. These coefficients were then predicted from the PD scores of the target and the peer, using multilevel modeling. Main findings were that persons scoring high on PD measures agreed less with their peers on their unique personality characteristics, and that such persons were described by, and described their peers, less favorably.

  2. Description of thoracoscopy and associated short-term cardiovascular and pulmonary effects in healthy cattle.

    PubMed

    Michaux, Hélène; Nichols, Sylvain; Babkine, Marie; Francoz, David

    2014-05-01

    To describe the optimal thoracoscopic approach to the bovine pleural cavity and evaluate the short-term effects of thoracoscopy on cardiovascular and pulmonary function of healthy cattle. 6 healthy adult Holstein cows (12 hemithoraxes). For each cow, thoracoscopy was performed in both the left and right hemithoraxes with a 24-hour interval between procedures. Cows were sedated and restrained in a standing position for each thoracoscopic examination. Examination of each hemithorax lasted for 30 minutes. Arterial blood gas variables, heart rate, and respiratory rate were assessed at predetermined times before, during, and after the procedures to monitor cardiovascular and pulmonary function. Thoracic ultrasonography was performed immediately and at 24 hours and 1 week after each thorascopic examination to evaluate the extent of residual pneumothorax. Insertion of the laparoscope into the pleural cavity at the ninth intercostal space 15 cm ventral to the transverse processes of the thoracic vertebrae provided optimal visibility of structures in both the left and right hemithoraxes. Most structures of the pleural cavity were equally visible from both sides except the esophagus and the dorsal branch of the vagus nerve, which were best observed in the left hemithorax, and the pericardium, which was best observed in the right hemithorax. Mild increases in heart and respiratory rates and moderate decreases in arterial oxygen saturation and Pao2 were detected during the procedures. Standing thoracoscopy was well tolerated in healthy adult dairy cattle and needs to be evaluated in cattle with pulmonary disease.

  3. Effective description of the short-time dynamics in open quantum systems

    NASA Astrophysics Data System (ADS)

    Rossi, Matteo A. C.; Foti, Caterina; Cuccoli, Alessandro; Trapani, Jacopo; Verrucchi, Paola; Paris, Matteo G. A.

    2017-09-01

    We address the dynamics of a bosonic system coupled to either a bosonic or a magnetic environment and derive a set of sufficient conditions that allow one to describe the dynamics in terms of the effective interaction with a classical fluctuating field. We find that for short interaction times the dynamics of the open system is described by a Gaussian noise map for several different interaction models and independently on the temperature of the environment. In order to go beyond a qualitative understanding of the origin and physical meaning of the above short-time constraint, we take a general viewpoint and, based on an algebraic approach, suggest that any quantum environment can be described by classical fields whenever global symmetries lead to the definition of environmental operators that remain well defined when increasing the size, i.e., the number of dynamical variables, of the environment. In the case of the bosonic environment this statement is exactly demonstrated via a constructive procedure that explicitly shows why a large number of environmental dynamical variables and, necessarily, global symmetries, entail the set of conditions derived in the first part of the work.

  4. New effective-one-body description of coalescing nonprecessing spinning black-hole binaries

    NASA Astrophysics Data System (ADS)

    Damour, Thibault; Nagar, Alessandro

    2014-08-01

    We present a new, tunable effective-one-body (EOB) model of the motion and radiation of coalescing black-hole binaries with arbitrary mass ratio and aligned spins. The most novel feature of our formalism is the introduction, and systematic use, of the (gauge-invariant) concept of centrifugal radius rc. In the spinning small mass-ratio limit, the main radial potential expressed in terms of rc differs very little (and only multiplicatively so) from the usual Schwarzschild potential 1-2M/rc. This motivates a new, multiplicative way of blending finite-mass-ratio deformations with spin deformations. In the present exploratory work we consider a minimal version of our spinning EOB model (containing essentially only two adjustable parameters: one in the Hamiltonian and one in the waveform) and calibrate its (dominant mode) waveform against a sample of fifteen equal-mass, equal-spin waveforms produced by the SXS Collaboration, and covering the dimensionless spin range -0.95≤χ ≤+0.98. The numerical relativity/EOB phasing disagreement remains remarkably small (≲±0.15 rad) over the entire spin range.

  5. [Description of the long-term effects of breast feeding in the Hungarian guidelines for infant nutrition].

    PubMed

    Jakobik, Viktória; Martin-Bautista, Elena; Gage, Heather; Von Rosen-Von Hoewel, Julia; Laitinen, Kirsi; Schmid, Martina; Morgan, Jane; Williams, Peter; Campoy, Cristina; Koletzko, Berthold; Raats, Monique; Decsi, Tamás

    2011-10-09

    To identify and describe infant feeding policy documents in Hungary and compare them to the documents of other four European countries (England, Finland, Germany and Spain). The question was also addressed how the phenomenon of nutritional programming was represented in the documents. Policy documents on infant feeding were identified and analyzed in the five European countries by using uniform methods for searching and coding. Twenty-six documents were identified: 4 in England, 2 in Finland, 9 in Germany, 6 in Hungary and 5 in Spain. Altogether 203 statements linked to references were identified: benefits of breast-feeding in general (24%), protection against infections (32%), long-term advantages like the prevention of diabetes (31%) or allergy (12%). Considerable variations were found within and between countries in the evaluation of the duration and character of the positive effects. The majority of the statements in the Hungarian documents referred either to the role of breast-feeding in infection protection (n = 8), or to long-term protective effects (n = 13). Policy documents in the study countries varied both in their extent and in the description of the long-term effects of infant nutrition. Majority of the documents failed to contain evidence based discussion of the phenomenon of early nutritional programming.

  6. Implications of Efimov physics for the description of three and four nucleons in chiral effective field theory

    NASA Astrophysics Data System (ADS)

    Kievsky, A.; Viviani, M.; Gattobigio, M.; Girlanda, L.

    2017-02-01

    In chiral effective field theory the leading order (LO) nucleon-nucleon potential includes two contact terms, in the two spin channels S =0 ,1 , and the one-pion-exchange potential. When the pion degrees of freedom are integrated out, as in the pionless effective field theory, the LO potential includes two contact terms only. In the three-nucleon system, the pionless theory includes a three-nucleon contact term interaction at LO whereas the chiral effective theory does not. Accordingly arbitrary differences could be observed in the LO description of three- and four-nucleon binding energies. We analyze the two theories at LO and conclude that a three-nucleon contact term is necessary at this order in both theories. In turn this implies that subleading three-nucleon contact terms should be promoted to lower orders. Furthermore, this analysis shows that one single low-energy constant might be sufficient to explain the large values of the singlet and triplet scattering lengths.

  7. Effective Lagrangian description of Higgs mediated flavor violating electromagnetic transitions: Implications on lepton flavor violation

    SciTech Connect

    Aranda, J. I.; Tututi, E. S.; Toscano, J. J.

    2009-05-01

    Higgs mediated flavor violating electromagnetic interactions, induced at the one-loop level by a nondiagonal Hf{sub i}f{sub j} vertex, with f{sub i} and f{sub j} charged leptons or quarks, are studied within the context of a completely general effective Yukawa sector that comprises SU{sub L}(2)xU{sub Y}(1)-invariant operators of up to dimension-six. Exact formulae for the one-loop {gamma}f{sub i}f{sub j} and {gamma}{gamma}f{sub i}f{sub j} couplings are presented and their related processes used to study the phenomena of Higgs mediated lepton flavor violation. The experimental limit on the {mu}{yields}e{gamma} decay is used to derive a bound on the branching ratio of the {mu}{yields}e{gamma}{gamma} transition, which is 6 orders of magnitude stronger than the current experimental limit. Previous results on the {tau}{yields}{mu}{gamma} and {tau}{yields}{mu}{gamma}{gamma} decays are reproduced. The possibility of detecting signals of lepton flavor violation at {gamma}{gamma} colliders is explored through the {gamma}{gamma}{yields}l{sub i}l{sub j} reaction, putting special emphasis on the {tau}{mu} final state. Using the bound imposed on the H{tau}{mu} vertex by the current experimental data on the muon anomalous magnetic moment, it is found that about half a hundred events may be produced in the International Linear Collider.

  8. Is access to the body structural description sensitive to a body part's significance for action and cognition? A study of the sidedness effect using feet.

    PubMed

    Tessari, Alessia; Ottoboni, Giovanni; Baroni, Giulia; Symes, Ed; Nicoletti, Roberto

    2012-05-01

    There is evidence suggesting that viewing hands triggers automatic access to the Body Structural Description, a visual-spatial representation of human body parts configuration. Hands, however, have a special representational status within the brain because of their significance for action and cognition. We tested whether feet, less important in gestural and object-directed action, would similarly show automatic access to the Body Structural Description. Positive evidence of that would be finding a Sidedness effect (Ottoboni et al. J Exp Psychol Hum Percept Perform 31:778-789, 2005), a Simon-like paradigm previously used to study automatic hand recognition. This effect demonstrates that processing hands generates spatial codes corresponding to the side of the body on which the hand would be located within the Body Structural Description map. Feet were shown with toes pointing upwards (Experiment 1), without any connection to the ankle and the leg (Experiment 2) and with toes pointing downwards (Experiment 3). Results revealed a Sidedness effect in both Experiments 1 and 3: spatial compatibility occurred according to the side of the body that each foot would assume within the Body Structural Description. In Experiment 2, as already found in stimuli similarly featured, no effect emerged, due to the lack of the necessary anatomical links connecting the foot to a body. Results suggest that body parts with variable degrees of significance for action and cognition can access automatically the Body Structural Description hence reinforcing the hypothesis of its pure visuo-spatial nature.

  9. Teaching Descriptive Style.

    ERIC Educational Resources Information Center

    Brashers, H. C.

    1968-01-01

    As the inexperienced writer becomes aware of the issues involved in the composition of effective descriptive prose, he also develops a consistent control over his materials. The persona he chooses, if coherently thought out, can function as an index of many choices, helping him to manipulate the tone, intent, and mood of this style; to regulate…

  10. MCFire model technical description

    Treesearch

    David R. Conklin; James M. Lenihan; Dominique Bachelet; Ronald P. Neilson; John B. Kim

    2016-01-01

    MCFire is a computer program that simulates the occurrence and effects of wildfire on natural vegetation, as a submodel within the MC1 dynamic global vegetation model. This report is a technical description of the algorithms and parameter values used in MCFire, intended to encapsulate its design and features a higher level that is more conceptual than the level...

  11. The Moderating Role of Close versus Distal Peer Injunctive Norms and Interdependent Self-Construal in the Effects of Descriptive Norms on College Drinking.

    PubMed

    Yang, Bo

    2017-04-19

    Based on the theory of normative social behavior (Rimal & Real, 2005), this study examined the effects of descriptive norms, close versus distal peer injunctive norms, and interdependent self-construal on college students' intentions to consume alcohol. Results of a cross-sectional study conducted among U.S. college students (N = 581) found that descriptive norms, close, and distal peer injunctive norms had independent effects on college students' intentions to consume alcohol. Furthermore, close peer injunctive norms moderated the effects of descriptive norms on college students' intentions to consume alcohol and the interaction showed different patterns among students with a strong and weak interdependent self-construal. High levels of close peer injunctive norms weakened the relationship between descriptive norms and intentions to consume alcohol among students with a strong interdependent self-construal but strengthened the relationship between descriptive norms and intentions to consume alcohol among students with a weak interdependent self-construal. Implications of the findings for norms-based research and college drinking interventions are discussed.

  12. One electron in a cavity

    SciTech Connect

    Gabrielse, G.; Tan, J.

    1994-12-31

    Measurements of the anomalous magnetic moment of the electron a provide the most stringent test of quantum electrodynamics (QED). This theory predicts corrections to the simplest Dirac theory due to the interaction of an electron with the fluctuating radiation modes of the electromagnetic vacuum. It relates a to an asymptotic series in powers of the fine structure constant {alpha}. 40 refs., 23 figs.

  13. Detailed Evaluation of the Geometric and Electronic Structures of One-electron Oxidized Group 10 (Ni, Pd, and Pt) Metal(II)-(Disalicylidene)diamine Complexes

    PubMed Central

    Stack, T. Daniel P.

    2009-01-01

    The geometric and electronic structures of a series of one-electron oxidized group 10 metal salens (Ni, Pd, Pt) have been investigated in solution and in the solid state. Ni (1) and Pd (2) complexes of the tetradentate salen ligand N,N’-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine (H2Salcn) have been examined along with the Pt (3) complex of the salen ligand N,N’-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylenediamine (H2Salen). All three oxidized compounds exist as ligand radical species in solution and in the solid state. The solid state structures of [1]+ and [3]+ exhibit a symmetric coordination sphere contraction relative to the neutral forms. By contrast, the coordination sphere of the Pd derivative [2]+ exhibits a pronounced asymmetry in the solid state. In solution, the oxidized derivatives display intense low-energy NIR transitions consistent with their classification as ligand radical compounds. Interestingly, the degree of communication between the phenolate moieties depends strongly on the central metal ion, within the Ni, Pd, and Pt series. Electrochemical measurements and UV-Vis-NIR spectroscopy, in conjunction with DFT calculations provide insights into the degree of delocalization of the one-electron hole in these systems. The Pd complex [2]+ is the least delocalized and is best described as a borderline Class II/III intervalence complex based on the Robin-Day classification system. The Ni [1]+ and Pt [3]+ analogues are Class III (fully delocalized) intervalence compounds. Delocalization is dependent on the electronic coupling between the redox-active phenolate ligands, mediated by overlap between the formally filled metal dxz orbital and the appropriate ligand molecular orbital. The degree of coupling increases in the order Pd < Ni < Pt for the one-electron oxidized group 10 metal salens. PMID:19639970

  14. Detailed evaluation of the geometric and electronic structures of one-electron oxidized group 10 (Ni, Pd, and Pt) metal(II)-(disalicylidene)diamine complexes.

    PubMed

    Shimazaki, Yuichi; Stack, T Daniel P; Storr, Tim

    2009-09-07

    The geometric and electronic structures of a series of one-electron oxidized group 10 metal salens (Ni, Pd, Pt) have been investigated in solution and in the solid state. Ni (1) and Pd (2) complexes of the tetradentate salen ligand N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine (H(2)Salcn) have been examined along with the Pt (3) complex of the salen ligand N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylenediamine (H(2)Salen). All three oxidized compounds exist as ligand radical species in solution and in the solid state. The solid state structures of [1](+) and [3](+) exhibit a symmetric coordination sphere contraction relative to the neutral forms. By contrast, the coordination sphere of the Pd derivative [2](+) exhibits a pronounced asymmetry in the solid state. In solution, the oxidized derivatives display intense low-energy NIR transitions consistent with their classification as ligand radical compounds. Interestingly, the degree of communication between the phenolate moieties depends strongly on the central metal ion, within the Ni, Pd, and Pt series. Electrochemical measurements and UV-vis-NIR spectroscopy, in conjunction with density functional theory calculations provide insights into the degree of delocalization of the one-electron hole in these systems. The Pd complex [2](+) is the least delocalized and is best described as a borderline Class II/III intervalence complex based on the Robin-Day classification system. The Ni [1](+) and Pt [3](+) analogues are Class III (fully delocalized) intervalence compounds. Delocalization is dependent on the electronic coupling between the redox-active phenolate ligands, mediated by overlap between the formally filled metal d(xz) orbital and the appropriate ligand molecular orbital. The degree of coupling increases in the order Pd < Ni < Pt for the one-electron oxidized group 10 metal salens.

  15. Ab initio description of continuum effects in A=11 exotic systems with chiral NN+3N forces

    NASA Astrophysics Data System (ADS)

    Calci, Angelo; Navratil, Petr; Roth, Robert; Dohet-Eraly, Jeremy; Quaglioni, Sofia; Hupin, Guillaume

    2016-09-01

    Based on the fundamental symmetries of QCD, chiral effective field theory (EFT) provides two- (NN), three- (3N) and many-nucleon interactions in a consistent and systematically improvable scheme. The rapid developments to construct divers families of chiral NN+3N interactions and the conceptual and technical improvements of ab initio many-body approaches pose a great opportunity for nuclear physics. By studying particular interesting phenomena in nuclear structure and reaction observables one can discriminate between different forces and study the predictive power of chiral EFT. The accurate description of the 11Be nucleus, in particular, the ground-state parity inversion and exceptionally strong E1 transition between its two bound states constitute an enormous challenge for the developments of nuclear forces and many-body approaches. We present a sensitivity analysis of structure and reaction observables to different NN+3N interactions in 11Be and n+10Be as well as the mirror p+10C scattering using the ab initio NCSM with continuum (NCSMC). Supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Work Proposal No. SCW1158. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada.

  16. Effect of the Bethe surface description on the electronic excitations induced by energetic proton beams in liquid water and DNA

    NASA Astrophysics Data System (ADS)

    Abril, Isabel; Denton, Cristian D.; de Vera, Pablo; Kyriakou, Ioanna; Emfietzoglou, Dimitris; Garcia-Molina, Rafael

    2010-06-01

    The irradiation of biological systems by energetic ion beams has multiple applications in medical physics and space radiation health, such as hadrontherapy for cancer treatment or protection of astronauts against space radiation. Therefore, for a better control and understanding of the effects of radiation damage in living tissues, it is necessary to advance an accurate description of the energy loss from the ion beam to the target. In the present work we use the dielectric formalism to calculate the probability for an energetic proton to produce electronic excitations in two targets of high biological interest, namely, liquid water and DNA. Also, the mean energy of the electronic excitations in these targets is found as a function of the incident proton energy. The electronic response of the target, characterized by its energy-loss function (ELF), is described by several models that fit the available experimental optical data (at zero momentum transfer), but use different approaches to obtain the Bethe surface, that is, to extend the ELF to any energy and momentum transferred.

  17. Exploring the effects of age and delay on children's person identifications: verbal descriptions, lineup performance, and the influence of wildcards.

    PubMed

    Karageorge, Aspasia; Zajac, Rachel

    2011-05-01

    We explored the effects of age and retention interval on several measures of children's person identification ability: verbal descriptions, lineup performance, and the success of a 'wildcard'--a photo of a silhouetted figure with a large question mark superimposed--in reducing children's tendency to choose from target-absent lineups. Children aged 5-7 years (N= 101) and 8-11 years (N= 109) were briefly exposed to an experimental confederate during a staged event. Either 1-2 days or 2 weeks later, children described the confederate and were then presented with either a target-present or -absent lineup. Within each group, approximately half of the children were presented with a wildcard and half were not. Target-present lineup performance improved as age increased. Compared to control children, children in the wildcard condition were more likely to correctly reject the target-absent lineup, and less likely to identify the innocent suspect. The wildcard did not influence children's target-present lineup accuracy, nor did delay exert an influence on any of our measures of lineup performance. These findings extend our knowledge of children's person identifications, as well as providing further support for the use of wildcards in photographic lineups. ©2010 The British Psychological Society.

  18. Improved effective-one-body description of coalescing nonspinning black-hole binaries and its numerical-relativity completion

    NASA Astrophysics Data System (ADS)

    Damour, Thibault; Nagar, Alessandro; Bernuzzi, Sebastiano

    2013-04-01

    We improve the effective-one-body (EOB) description of nonspinning coalescing black-hole binaries by incorporating several recent analytical advances, notably: (i) logarithmic contributions to the conservative dynamics; (ii) resummed horizon-absorption contribution to the orbital angular momentum loss; and (iii) a specific radial component of the radiation-reaction force implied by consistency with the azimuthal one. We then complete this analytically improved EOB model by comparing it to accurate numerical-relativity (NR) simulations performed by the Caltech-Cornell-CITA group for mass ratios q=(1,2,3,4,6). In particular, the comparison to NR data allows us to determine with high accuracy (˜10-4) the value of the main EOB radial potential: A(u;ν), where u=GM/(Rc2) is the interbody gravitational potential and ν=q/(q+1)2 is the symmetric mass ratio. We introduce a new technique for extracting from NR data an intrinsic measure of the phase evolution [Qω(ω) diagnostics]. Aligning the NR-completed EOB quadrupolar waveform and the NR one at low frequencies, we find that they keep agreeing (in phase and amplitude) within the NR uncertainties throughout the evolution for all mass ratios considered. We also find good agreement for several subdominant multipoles without having to introduce and tune any extra parameters.

  19. Anodic preparation of [Re2Cp2(CO)6]2+: a dimeric dication that provides the powerful one-electron oxidant [ReCp(CO)3]+.

    PubMed

    Chong, Daesung; Nafady, Ayman; Costa, Paulo Jorge; Calhorda, Maria José; Geiger, William E

    2005-11-16

    The half-sandwich piano-stool compounds Re(eta5-C5R5)(CO)3 (1, R = H; or 2, R = Me) are oxidized to the corresponding 17-electron Re(II) cations at glassy carbon anodes in CH2Cl2/[NBu4][B(C6F5)4]. Despite the very strongly positive E1/2 values of the couples (1.16 V for 1/1+ and 0.91 V for 2/2+ vs ferrocene/ferrocenium), the radical cations are persistent in this medium and exist in equilibrium with the corresponding dimeric dications, which may be cathodically reduced back to the neutral starting material. DFT calculations show that the dimer of 1+ achieves its stability through formation of a single long (almost 3.3 A) Re-Re bond made possible when the HOMO in 1 is rehybridized away from the metal in the one-electron oxidation process. The pure salts [1][B(C6F5)4]2 and [2][B(C6F5)4]2 were isolated by preparative anodic electrochemistry. The former may be used for storage of the very strong one-electron oxidant 1+, which was used to prepare a number of oxidation products as their [B(C6F5)4]- salts.

  20. Why do multi-attribute utility instruments produce different utilities: the relative importance of the descriptive systems, scale and 'micro-utility' effects.

    PubMed

    Richardson, Jeff; Iezzi, Angelo; Khan, Munir A

    2015-08-01

    Health state utilities measured by the major multi-attribute utility instruments differ. Understanding the reasons for this is important for the choice of instrument and for research designed to reconcile these differences. This paper investigates these reasons by explaining pairwise differences between utilities derived from six multi-attribute utility instruments in terms of (1) their implicit measurement scales; (2) the structure of their descriptive systems; and (3) 'micro-utility effects', scale-adjusted differences attributable to their utility formula. The EQ-5D-5L, SF-6D, HUI 3, 15D and AQoL-8D were administered to 8,019 individuals. Utilities and unweighted values were calculated using each instrument. Scale effects were determined by the linear relationship between utilities, the effect of the descriptive system by comparison of scale-adjusted values and 'micro-utility effects' by the unexplained difference between utilities and values. Overall, 66 % of the differences between utilities was attributable to the descriptive systems, 30.3 % to scale effects and 3.7 % to micro-utility effects. Results imply that the revision of utility algorithms will not reconcile differences between instruments. The dominating importance of the descriptive system highlights the need for researchers to select the instrument most capable of describing the health states relevant for a study. Reconciliation of inconsistent utilities produced by different instruments must focus primarily upon the content of the descriptive system. Utility weights primarily determine the measurement scale. Other differences, attributable to utility formula, are comparatively unimportant.

  1. Spacelab J experiment descriptions

    NASA Technical Reports Server (NTRS)

    Miller, Teresa Y. (Editor)

    1993-01-01

    Brief descriptions of the experiment investigations for the Spacelab J Mission which was launched from the Kennedy Space Center aboard the Endeavour in Sept. 1992 are presented. Experiments cover the following: semiconductor crystals; single crystals; superconducting composite materials; crystal growth; bubble behavior in weightlessness; microgravity environment; health monitoring of Payload Specialists; cultured plant cells; effect of low gravity on calcium metabolism and bone formation; and circadian rhythm.

  2. Spacelab J experiment descriptions

    SciTech Connect

    Miller, T.Y.

    1993-08-01

    Brief descriptions of the experiment investigations for the Spacelab J Mission which was launched from the Kennedy Space Center aboard the Endeavour in Sept. 1992 are presented. Experiments cover the following: semiconductor crystals; single crystals; superconducting composite materials; crystal growth; bubble behavior in weightlessness; microgravity environment; health monitoring of Payload Specialists; cultured plant cells; effect of low gravity on calcium metabolism and bone formation; and circadian rhythm. Separate abstracts have been prepared for articles from this report.

  3. A manganese(V)-oxo π-cation radical complex: influence of one-electron oxidation on oxygen-atom transfer.

    PubMed

    Prokop, Katharine A; Neu, Heather M; de Visser, Sam P; Goldberg, David P

    2011-10-12

    One-electron oxidation of Mn(V)-oxo corrolazine 2 affords 2(+), the first example of a Mn(V)(O) π-cation radical porphyrinoid complex, which was characterized by UV-vis, EPR, LDI-MS, and DFT methods. Access to 2 and 2(+) allowed for a direct comparison of their reactivities in oxygen-atom transfer (OAT) reactions. Both complexes are capable of OAT to PPh(3) and RSR substrates, and 2(+) was found to be a more potent oxidant than 2. Analysis of rate constants and activation parameters, together with DFT calculations, points to a concerted OAT mechanism for 2(+) and 2 and indicates that the greater electrophilicity of 2(+) likely plays a dominant role in enhancing its reactivity. These results are relevant to comparisons between Compound I and Compound II in heme enzymes.

  4. Orthogonal natural atomic orbitals form an appropriate one-electron basis for expanding CASSCF wave functions into localized bonding schemes and their weights.

    PubMed

    Bachler, Vinzenz

    2007-09-01

    Localized bonding schemes and their weights have been obtained for the pi-electron system of nitrone by expanding complete active space self-consistent field wave functions into a set of Slater determinants composed of orthogonal natural atomic orbitals (NAOs) of Weinhold and Landis (Valency and Bonding: A Natural Bond Orbital Donor-Acceptor Perspective, 2005). Thus, the derived bonding schemes are close to orthogonal valence bond structures. The calculated sequence of bonding scheme weights accords with the sequence of genuine resonance structure weights derived previously by Ohanessian and Hiberty (Chem Phys Lett 1987, 137, 437), who employed nonorthogonal atomic orbitals. This accord supports the notion that NAOs form an appropriate orthogonal one-electron basis for expanding complete active space self-consistent field wave functions into meaningful bonding schemes and their weights.

  5. Nitrite Reduction to Nitrous Oxide and Ammonia by TiO2 Electrons in a Colloid Solution via Consecutive One-Electron Transfer Reactions.

    PubMed

    Goldstein, Sara; Behar, David; Rajh, Tijana; Rabani, Joseph

    2016-04-21

    The mechanism of nitrite reduction by excess electrons on TiO2 nanoparticles (eTiO2(-)) was studied under anaerobic conditions. TiO2 was loaded with up to 75 electrons per particle, induced by γ-irradiation of acidic TiO2 colloid solutions containing 2-propanol. Time-resolved kinetics and material analysis were performed, mostly at 1.66 g L(-1) TiO2. At relatively low nitrite concentrations (R = [eTiO2(-)]o/[nitrite]o > 1.5), eTiO2(-) decays via two consecutive processes; at higher concentrations, only one decay step is observed. The stoichiometric ratio Δ[eTiO2(-)]/[nitrite]o of the faster process is about 2. This process involves the one-electron reduction of nitrite, forming the nitrite radical (k1 = (2.0 ± 0.2) × 10(6) M(-1) s(-1)), which further reacts with eTiO2(-) (k2) in competition with its dehydration to nitric oxide (NO) (k3). The ratios k2/k3 = (3.0 ± 0.5) × 10(3) M(-1) and k2 > 1 × 10(6) M(-1) s(-1) were derived from kinetic simulations and product analysis. The major product of this process is NO. The slower stage of the kinetics involves the reduction of NO by eTiO2(-), and the detailed mechanism of this process has been discussed in our earlier publication. The results reported in this study suggest that several intermediates, including NO and NH2OH, are adsorbed on the titanium nanoparticles and give rise to inverse dependency of the respective reaction rates on the TiO2 concentration. It is demonstrated that the reduction of nitrite by eTiO2(-) yields mainly N2O and NH3 via consecutive one-electron transfer reactions.

  6. One-electron oxidation pathway of thiols by peroxynitrite in biological fluids: bicarbonate and ascorbate promote the formation of albumin disulphide dimers in human blood plasma.

    PubMed Central

    Scorza, G; Minetti, M

    1998-01-01

    Recent studies have shown that peroxynitrite oxidizes thiol groups through competing one- and two-electron pathways. The two-electron pathway is mediated by the peroxynitrite anion and prevails quantitatively over the one-electron pathway, which is mediated by peroxynitrous acid or a reactive species derived from it. In CO2-containing fluids the oxidation of thiols might follow a different mechanism owing to the rapid formation of a different oxidant, the nitrosoperoxycarbonate anion (ONOOCO2(-)). Here we present evidence that in blood plasma peroxynitrite induces the formation of a disulphide cross-linked protein identified by immunological (anti-albumin antibodies) and biochemical criteria (peptide mapping) as a dimer of serum albumin. The albumin dimer did not form in plasma devoid of CO2 and its formation was enhanced by ascorbate. However, analysis of thiol groups showed that reconstituting dialysed plasma with NaHCO3 protected protein thiols against the oxidation mediated by peroxynitrite and that the simultaneouspresence of ascorbate provided further protection. Ascorbate alone did not protect thiol groups from peroxynitrite-mediated oxidation. ESR spin-trapping studies with N-t-butyl-alpha-phenylnitrone (PBN) revealed that peroxynitrite induced the formation of protein thiyl radicals and their intensity was markedly decreased by plasma dialysis and restored by reconstitution with NaHCO3. PBN completely inhibited the formation of albumin dimer. Moreover, the addition of iron-diethyldithiocarbamate to plasma demonstrated that peroxynitrite induced the formation of protein S-nitrosothiols and/or S-nitrothiols. Our results are consistent with the hypothesis that NaHCO3 favours the one-electron oxidation of thiols by peroxynitrite with formation of thiyl radicals, ;NO2, and RSNOx. Thiyl radicals, in turn, are involved in chain reactions by which thiols are oxidized to disulphides. PMID:9425126

  7. Pain control methods in use and perceived effectiveness by patients with Ehlers-Danlos syndrome: a descriptive study.

    PubMed

    Arthur, Karen; Caldwell, Karen; Forehand, Samantha; Davis, Keith

    2016-01-01

    The purpose of this study was to assess the pain control methods in use by patients who have Ehlers-Danlos Syndrome (EDS), a group of connective tissue disorders, and their perceived effectiveness. This descriptive study involved 1179 adults diagnosed with EDS who completed an anonymous on-line survey. The survey consisted of demographics information, the Patient Reported Outcomes Measurement Information System (PROMIS) Pain-Behavior, PROMIS Pain-Interference, and Neuro QOL Satisfaction with Social Roles and Activities scales, as well as a modified version of the Pain Management Strategies Survey. Respondents reported having to seek out confirmation of their EDS diagnosis with multiple healthcare providers, which implies the difficulty many people with EDS face when trying to gain access to appropriate treatment. Patients with EDS experience higher levels of pain interference and lower satisfaction with social roles and activities compared to national norms. Among the treatment modalities in this study, those perceived as most helpful for acute pain control were opioids, surgical interventions, splints and braces, avoidance of potentially dangerous activities and heat therapy. Chronic pain treatments rated as most helpful were opioids, splints or braces and surgical interventions. For methods used for both acute and chronic pain, those perceived as most helpful were opioids, massage therapies, splints or braces, heat therapy and avoiding potentially dangerous activities. EDS is a complex, multi-systemic condition that can be difficult to diagnose and poses challenges for healthcare practitioners who engage with EDS patients in holistic care. Improved healthcare provider knowledge of EDS is needed, and additional research on the co-occurring diagnoses with EDS may assist in comprehensive pain management for EDS patients. Ehlers-Danlos Syndrome (EDS) is a group of connective tissue disorders associated with defective production of collagen, which can dramatically

  8. Descriptions of Personal Experiences: Effects on Students' Learning and Behavioral Intentions toward Peers with Attention-Deficit/Hyperactivity Disorder

    ERIC Educational Resources Information Center

    Saecker, Lee B.; Skinner, Amy L.; Skinner, Christopher H.; Rowland, Emily; Kirk, Emily

    2010-01-01

    High-school students were shown an educational video designed to dispel 12 common myths regarding Attention-Deficit/Hyperactivity Disorder (ADHD) by describing each myth and then presenting accurate information. The experimental group viewed a video that was supplemented by the speaker acknowledging that he had ADHD and providing descriptions of…

  9. [Effectivity and satisfaction with the treatment for dyslipidemia with pitavastatin. Multicentric, descriptive, post authorised and observational study (REINA study)].

    PubMed

    Rodríguez Arroyo, Luis Alberto; Díaz Rodríguez, Angel; Pintó Sala, Xavier; Coca Payeras, Antonio; Rius Tarruella, Joan

    2014-01-01

    Evaluating the therapeutical adherence as well as the patient' satisfaction with the treatment should be considered to optimize lipidic control. The REINA Study evaluates the grade of satisfaction in dyslipidemic patients treated with pitavastatin. The current study was observational, descriptive, transversal and multi-centric with patients from our country only. The following data were collected in each case: Morisky-Green test and TSQM-9 for patients older than 18 years old, with dyslipidemia treated with pitavastatin in the last 12 weeks. We studied 6,489 patients (60.0% males) from Primary Health (52.7%) and Specialised Health (47.3%), with age (mean) = 60.9 ± 11.2 years by aleatory sampling. 72.3% of patients achieved an adequate control with 2mg/day of pitavastatin. General satisfaction with the treatment was 73.20 points (95% CI: 58.17-87.23). Patients who followed the treatment (65%) showed better data of satisfaction with the drug (77.70 [95% CI: 65.20-90.20]), of global satisfaction (75.00 [95% CI: 61.50-88.50]) and their satisfaction with the drug efficiency was higher (72.50 [95% CI: 57.70-87.30]) than in the patients who did not finish the treatment (72.70 [95% CI: 59.30-85.74]; 68.5 [95% CI: 53.20-83.80] and 67.80 [95% CI: 53.70-81.90], respectively), P < .0001, without any difference between the two primary care systems. The validation of the satisfaction is a crucial indicator in the evaluation of the services offered in health. Patients with the highest grade of satisfaction present better therapeutical adherence, and such a relation is bidirectional. The individuals who are satisfied and who followed the treatment obtained better clinical results. Pitavastatin is an effective therapeutic alternative for patients with dyslipidemia. Copyright © 2013 Sociedad Española de Arteriosclerosis. Published by Elsevier España. All rights reserved.

  10. Charlie brown versus snow white: the effects of descriptiveness on young and older adults' retrieval of proper names.

    PubMed

    Fogler, Kethera A; James, Lori E

    2007-07-01

    The nondescriptive nature of proper names has been suggested as one reason that people experience particular difficulty learning and recalling names. This experiment tested whether the exacerbated difficulty experienced by older adults in retrieving proper names is partly due to names' nondescriptive quality. Young and older participants named pictures of well-known cartoon characters that have either descriptive names (e.g., Snow White, Big Bird) or nondescriptive names (e.g., Charlie Brown, Garfield). Older adults were particularly impaired at retrieving nondescriptive names. Results indicate that theories of name memory must represent the nondescriptive nature of names and account for the decreased retrieval difficulty for descriptive compared with nondescriptive names in aging.

  11. Effect of Manipulating Descriptive Norms and Positive Outcome Expectations on Physical Activity of University Students During Exams.

    PubMed

    Crozier, Alyson J; Spink, Kevin S

    2017-06-01

    This experimental study examined the interaction between messages conveying different levels of descriptive norms and positive outcome expectations on university students' engagement in moderate and vigorous physical activity over an exam period. Using a pre-post design, university students entering a final examination period (N = 74) were randomly assigned to one of four message conditions, receiving a message motivating them to exercise over the exam period. Messages included both a descriptive norm (how many others reported being active during a previous exam period; high vs. low) and a positive outcome expectation (those who exercise during exams report better grades; high vs. low). The results from an analysis of covariance (ANCOVA), controlling for baseline levels of daily physical activity, revealed a significant interaction. Post hoc analyses indicated that when the descriptive norm was high, those who received a high positive outcome expectation reported being more active during the exam period compared to those receiving the low positive outcome expectation. Results provide preliminary support for the idea that activity during an exam period can be positively influenced if individuals are presented with normative messages that (a) many others are being active during the exams and (b) many of those being active also are benefiting academically.

  12. Nitric Oxide Reduction to Ammonia by TiO2 Electrons in Colloid Solution via Consecutive One-Electron Transfer Steps

    DOE PAGES

    Goldstein, Sara; Behar, David; Rajh, Tijana; ...

    2015-03-02

    The reaction mechanism of nitric oxide (NO) reduction by excess electrons on TiO2 nanoparticles (eTiO2–) has been studied under anaerobic conditions. TiO2 was loaded with 10–130 electrons per particle using γ-irradiation of acidic TiO2 colloid solutions containing 2-propanol. The study is based on time-resolved kinetics and reactants and products analysis. The reduction of NO by eTiO2– is interpreted in terms of competition between a reaction path leading to formation of NH3 and a path leading to N2O and N2. The proposed mechanism involves consecutive one-electron transfers of NO, and its reduction intermediates HNO, NH2O•, and NH2OH. The results show thatmore » eTiO2– does not reduce N2O and N2. Second-order rate constants of eTiO2– reactions with NO (740 ± 30 M–1 s–1) and NH2OH (270 ± 30 M–1 s–1) have been determined employing the rapid-mixing stopped-flow technique and that with HNO (>1.3 × 106 M–1 s–1) was derived from fitting the kinetic traces to the suggested reaction mechanism, which is discussed in detail.« less

  13. New Measurement of the Electron Magnetic Moment and the Fine Structure Constant: A First Application of a One-Electron Quantum Cyclotron

    ScienceCinema

    Gabrielse, Gerald [Harvard University, Cambridge, Massachusetts, United States

    2016-07-12

    Remarkably, the famous UW measurement of the electron magnetic moment has stood since 1987. With QED theory, this measurement has determined the accepted value of the fine structure constant. This colloquium is about a new Harvard measurement of these fundamental constants. The new measurement has an uncertainty that is about six times smaller, and it shifts the values by 1.7 standard deviations. One electron suspended in a Penning trap is used for the new measurement, like in the old measurement. What is different is that the lowest quantum levels of the spin and cyclotron motion are resolved, and the cyclotron as well as spin frequencies are determined using quantum jump spectroscopy. In addition, a 0.1 mK Penning trap that is also a cylindrical microwave cavity is used to control the radiation field, to suppress spontaneous emission by more than a factor of 100, to control cavity shifts, and to eliminate the blackbody photons that otherwise stimulate excitations from the cyclotron ground state. Finally, great signal-to-noise for one-quantum transitions is obtained using electronic feedback to realize the first one-particle self-excited oscillator. The new methods may also allow a million times improved measurement of the 500 times small antiproton magnetic moment.

  14. Spiro- and dispiro-1,2-dioxolanes: contribution of iron(II)-mediated one-electron vs two-electron reduction to the activity of antimalarial peroxides.

    PubMed

    Wang, Xiaofang; Dong, Yuxiang; Wittlin, Sergio; Creek, Darren; Chollet, Jacques; Charman, Susan A; Tomas, Josefina Santo; Scheurer, Christian; Snyder, Christopher; Vennerstrom, Jonathan L

    2007-11-15

    Fourteen spiro- and dispiro-1,2-dioxolanes were synthesized by peroxycarbenium ion annulations with alkenes in yields ranging from 30% to 94%. Peroxycarbenium ion precursors included triethylsilyldiperoxyketals and -acetals derived from geminal dihydroperoxides and from a new method employing triethylsilylperoxyketals and -acetals derived from ozonolysis of alkenes. The 1,2-dioxolanes were either inactive or orders of magnitude less potent than the corresponding 1,2,4-trioxolanes or artemisinin against P. falciparum in vitro and P. berghei in vivo. In reactions with iron(II), the predominant reaction course for 1,2-dioxolane 3a was two-electron reduction. In contrast, the corresponding 1,2,4-trioxolane 1 and the 1,2,4-trioxane artemisinin undergo primarily one-electron iron(II)-mediated reductions. The key structural element in the latter peroxides appears to be an oxygen atom attached to one or both of the peroxide-bearing carbon atoms that permits rapid beta-scission reactions (or H shifts) to form primary or secondary carbon-centered radicals rather than further reduction of the initially formed Fe(III) complexed oxy radicals.

  15. Calmodulin Methionine Residues are Targets For One-Electron Oxidation by Hydroxyl Radicals: Formation of S therefore N three-electron bonded Radical Complexes

    SciTech Connect

    Nauser, Thomas; Jacoby, Michael E.; Koppenol, Willem H.; Squier, Thomas C.; Schoneich, Christian

    2005-02-01

    The one-electron (1e) oxidation of organic sulfides and methionine (Met) constitutes an important reaction mechanism in vivo.1,2 Evidence for a Cu(II)-catalyzed oxidation of Met35 in the Alzheimer's disease -amyloid peptide was obtained,3 and, based on theoretical studies, Met radical cations were proposed as intermediates.4 In the structure of -amyloid peptide, the formation of Met radical cations appears to be facilitated by a preexisting close sulfur-oxygen (S-O) interaction between the Met35 sulfur and the carbonyl oxygen of the peptide bond C-terminal to Ile31.5 Substitution of Ile31 with Pro31 abolishes this S-O interaction,5 significantly reducing the ability of -amyloid to reduce Cu(II), and converts the neurotoxic wild-type -amyloid into a non-toxic peptide.6 The preexisting S-O bond characterized for wild-type -amyloid suggests that electron transfer from Met35 to Cu(II) is supported through stabilization of the Met radical cation by the electron-rich carbonyl oxygen, generating an SO-bonded7 sulfide radical cation (Scheme 1, reaction 1).5

  16. Solution of the Dirac equation using the Rayleigh-Ritz method: Flexible basis coupling large and small components. Results for one-electron systems

    NASA Astrophysics Data System (ADS)

    Baǧcı, A.; Hoggan, P. E.

    2016-07-01

    An algebraic solution of the Dirac equation is reinvestigated. Slater-type spinor orbitals and their corresponding system of differential equations are defined in two- and four-component formalism. They describe the radial function in components of the wave function of the Dirac equation solution to high accuracy. They constitute the matrix elements arising in a generalized eigenvalue equation. These terms are evaluated through prolate spheroidal coordinates. The corresponding integrals are calculated by the numerical global-adaptive method taking into account the Gauss-Kronrod numerical integration extension. Sample calculations are performed using flexible basis sets generated with both signs of the relativistic angular momentum quantum number κ . Applications to one-electron atoms and diatomics are detailed. Variationally optimum values for orbital parameters are obtained at given nuclear separation. Methods discussed in this work are capable of yielding highly accurate relativistic two-center integrals for all ranges of orbital parameters. This work provides an efficient way to overcome the problems that arise in relativistic calculations.

  17. Real-time propagation of the reduced one-electron density matrix in atom-centered Gaussian orbitals: application to absorption spectra of silicon clusters.

    PubMed

    Sun, Jin; Song, Jian; Zhao, Yi; Liang, Wan-Zhen

    2007-12-21

    We solve the time-dependent density functional theory equation by propagating the reduced one-electron density matrix in real-time domain. The efficiency of several standard solvers such as the short-iterative Krylov-subspace propagator, the low-order Magnus integration method with the matrix polynomial (MP) or Chebyshev matrix polynomial (CMP) expansion of the evolution operator, and Runge-Kutta algorithm are assessed. Fast methods for summing MP and CMP are implemented to speed the calculation of the matrix exponential. It is found that the exponential propagators can tolerate large time step size and retain the computational accuracy whereas the Krylov-subspace algorithm is a little inferior for a larger time step size compared with the second-order Magnus integration method with the MP/CMP expansion of the evolution operator in both weak and intense fields. As an application, we calculate the absorption spectra of hydrogen-passivated silicon nanoparticles Si(29)H(x). The popular hybrid and generalized gradient approximation exchange-correlation functionals are applied. We find that the experimental spectra can be reproduced by using B3LYP and that the silicon particles with sizes of 1 nm and the optical excitations at 3.7, 4.0, and 4.6 eV may consist of 29 Si atoms surrounded by 24 hydrogen atoms.

  18. Solution of the Dirac equation using the Rayleigh-Ritz method: Flexible basis coupling large and small components. Results for one-electron systems.

    PubMed

    Bağcı, A; Hoggan, P E

    2016-07-01

    An algebraic solution of the Dirac equation is reinvestigated. Slater-type spinor orbitals and their corresponding system of differential equations are defined in two- and four-component formalism. They describe the radial function in components of the wave function of the Dirac equation solution to high accuracy. They constitute the matrix elements arising in a generalized eigenvalue equation. These terms are evaluated through prolate spheroidal coordinates. The corresponding integrals are calculated by the numerical global-adaptive method taking into account the Gauss-Kronrod numerical integration extension. Sample calculations are performed using flexible basis sets generated with both signs of the relativistic angular momentum quantum number κ. Applications to one-electron atoms and diatomics are detailed. Variationally optimum values for orbital parameters are obtained at given nuclear separation. Methods discussed in this work are capable of yielding highly accurate relativistic two-center integrals for all ranges of orbital parameters. This work provides an efficient way to overcome the problems that arise in relativistic calculations.

  19. Unified Description of NN and YN Interactions in a Quark Model with Effective Meson-Exchange Potentials

    NASA Astrophysics Data System (ADS)

    Fujiwara, Y.; Nakamoto, C.; Suzuki, Y.

    1996-03-01

    A simultaneous description of the NN and YN interactions is attempted in the resonating-group formulation of the spin-flavor SU6 quark model, in which the full Fermi-Breit interaction with explicit quark-mass dependence acts between quarks, and all the mesons of scalar and pseudoscalar nonets couple directly to quarks. An overall agreement with the existing data is obtained with few adjustable parameters. In the Λp elastic total cross sections, the cusp structure at the ΣN threshold is strongly enhanced by the antisymmetric LS- force generated from the Fermi-Breit interaction.

  20. Consumer perceptions, descriptive profile, and mechanical properties of a novel product with chickpea flour: Effect of ingredients.

    PubMed

    Jiménez, María José; Tárrega, Amparo; Fuentes, Raúl; Canet, Wenceslao; Álvarez, María Dolores

    2016-09-01

    Increasingly popular in the West is hummus, a spread that is made with pureed chickpeas and other healthful ingredients. The changes in texture measurements and sensory properties in a novel chickpea flour-based product occurring when water is partially replaced by common ingredients of hummus were investigated. Eleven chickpea gels containing different amounts of minced garlic, lemon juice, curry powder, and inulin were prepared and compared with two control gels. These ingredients were chosen to make the product tastier, appealing, and similar to hummus. Instrumental texture tests were carried out: uniaxial compression, stress relaxation, and texture profile analysis. Quantitative descriptive analysis was used to describe differences in sensory properties perceived by a trained panel, whereas repertory grid method combined with free choice profile was used to determine differences perceived by untrained consumers. Gels with higher curry powder content presented lower force to breakdown, whereas increasing inulin content led to gels with higher hardness. Principal component analysis was applied to instrumental parameters and quantitative descriptive analysis data, whereas generalized Procrustes analysis was applied to free choice profile data. This newly developed chickpea gel may make a nutrition claim with respect to protein ("high in protein," or at least a "source of protein").

  1. Perspectives of Halogen Bonding Description in Scoring Functions and QSAR/QSPR: Substituent Effects in Aromatic Core.

    PubMed

    Titov, Oleg I; Shulga, Dmitry A; Palyulin, Vladimir A; Zefirov, Nikolay S

    2015-06-01

    Halogen bonding (XB) is a new promising interaction pattern in medicinal chemistry. It has predominantly electrostatic nature - high electrostatic potential anisotropy. However to fully unleash the potential of XB in rational drug design fast and robust empirical methods of XB description should be developed. Current approaches rely heavily on ab initio calculation for each molecule studied. Thus fast prediction of electrostatic parameters for description of XB for arbitrary organic molecules is of paramount importance to promptly establish QSAR/QSPR, virtual screening and molecular docking pipelines suitable for today's agile development requirements. The two most promising approaches to describe anisotropic electrostatic models - the extra point (EP) charge model and the multipole expansion (ME) model - were studied on their ability (1) to describe ab initio molecular electrostatic potential (MEP) and (2) to produce parameters that can be predicted for each molecule empirically rather than estimated via ab initio calculations. The reference ab initio MEP was calculated for a set of 730 substituted halobenzenes. Parameters for anisotropic electrostatics of both empirical models (EP and ME) studied were extracted from ab initio MEP. The FreeWilson and Hansch type QSPR models relating XB parameters with aromatic substituents were built and analyzed, providing the guidelines for further development. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. One-electron oxidation of diclofenac by human cytochrome P450s as a potential bioactivation mechanism for formation of 2'-(glutathion-S-yl)-deschloro-diclofenac.

    PubMed

    Boerma, Jan Simon; Vermeulen, Nico P E; Commandeur, Jan N M

    2014-01-25

    Reactive metabolites have been suggested to play a role in the idiosyncratic hepatotoxicity observed with diclofenac (DF). By structural identification of the GSH conjugates formed after P450-catalyzed bioactivation of DF, it was shown that three types of reactive intermediates were formed: p-benzoquinone imines, o-imine methide and arene-oxide. Recently, detection of 2'-(glutathion-S-yl)-deschloro-diclofenac (DDF-SG), resulting from chlorine substitution, suggested the existence of a fourth type of P450-dependent reactive intermediate whose inactivation by GSH is completely dependent on presence of glutathione S-transferase. In this study, fourteen recombinant cytochrome P450s and three flavin-containing monooxygenases were tested for their ability to produce oxidative DF metabolites and their corresponding GSH conjugates. Concerning the hydroxymetabolites and their GSH conjugates, results were consistent with previous studies. Unexpectedly, all tested recombinant P450s were able to form DDF-SG to almost similar extent. DDF-SG formation was found to be partially independent of NADPH and even occurred by heat-inactivated P450. However, product formation was fully dependent on both GSH and glutathione-S-transferase P1-1. DDF-SG formation was also observed in reactions with horseradish peroxidase in absence of hydrogen peroxide. Because DDF-SG was not formed by free iron, it appears that DF can be bioactivated by iron in hemeproteins. This was confirmed by DDF-SG formation by other hemeproteins such as hemoglobin. As a mechanism, we propose that DF is subject to heme-dependent one-electron oxidation. The resulting nitrogen radical cation, which might activate the chlorines of DF, then undergoes a GST-catalyzed nucleophilic aromatic substitution reaction in which the chlorine atom of the DF moiety is replaced by GSH.

  3. Nitric Oxide Reduction to Ammonia by TiO2 Electrons in Colloid Solution via Consecutive One-Electron Transfer Steps

    SciTech Connect

    Goldstein, Sara; Behar, David; Rajh, Tijana; Rabani, Joseph

    2015-03-02

    The reaction mechanism of nitric oxide (NO) reduction by excess electrons on TiO2 nanoparticles (eTiO2) has been studied under anaerobic conditions. TiO2 was loaded with 10–130 electrons per particle using γ-irradiation of acidic TiO2 colloid solutions containing 2-propanol. The study is based on time-resolved kinetics and reactants and products analysis. The reduction of NO by eTiO2 is interpreted in terms of competition between a reaction path leading to formation of NH3 and a path leading to N2O and N2. The proposed mechanism involves consecutive one-electron transfers of NO, and its reduction intermediates HNO, NH2O•, and NH2OH. The results show that eTiO2 does not reduce N2O and N2. Second-order rate constants of eTiO2 reactions with NO (740 ± 30 M–1 s–1) and NH2OH (270 ± 30 M–1 s–1) have been determined employing the rapid-mixing stopped-flow technique and that with HNO (>1.3 × 106 M–1 s–1) was derived from fitting the kinetic traces to the suggested reaction mechanism, which is discussed in detail.

  4. Theoretical study of one-electron-oxidized salen complexes of group 7 (Mn(iii), Tc(iii), and Re(iii)) and group 10 metals (Ni(ii), Pd(ii), and Pt(ii)) with the 3D-RISM-GMC-QDPT method: localized vs. delocalized ground and excited states in solution.

    PubMed

    Aono, Shinji; Nakagaki, Masayuki; Sakaki, Shigeyoshi

    2017-06-28

    One-electron oxidized salen complexes of Mn(iii) and Ni(ii) were recently reported to be unique mixed-valence compounds. Their electronic structures are sensitive to the salen ligand and solvation. We systematically investigated a series of one-electron oxidized salen complexes of group 7 metals (Mn(iii), Tc(iii), and Re(iii)) and their group 10 analogues (Ni(ii), Pd(ii), and Pt(ii)) using the general multi-configuration reference quasi-degenerate perturbation theory (GMC-QDPT) which was combined with the three-dimensional reference interaction site model self-consistent field theory (3D-RISM-SCF) to incorporate the solvation effect. The calculated absorption spectra and electronic structures agree with the experimental observation. The one-electron oxidized salen complexes of group 10 metals with a symmetrical salen ligand have a delocalized electronic structure belonging to class III (Robin-Day classification) in weakly polar solvents. The tendency for taking a delocalized electronic structure increases in the order Pd(ii) < Ni(ii) < Pt(ii). When the salen ligand is asymmetrical, the one-electron oxidized complexes have a localized electronic structure belonging to class II. The group 7 analogues of Mn(iii) and Tc(iii) have a localized electronic structure belonging to class II even in weakly polar solvents and even with a symmetrical salen ligand. However, the one-electron oxidized Re(iii) complex has no mixed-valence nature because one-electron oxidation occurs on the Re center. Theoretical study shows that the solvation effect plays a crucial role in determining the mixed-valence character, class II or III, and thereby its incorporation in the calculation is indispensable for correctly describing geometries, electronic structures, and the inter-valence absorption spectra of these complexes. The d orbital energy is one of the most important factors for determining the localization/delocalization electronic structures in these complexes. Detailed discussion of

  5. Unified description of {ital NN} and {ital YN} interactions in a quark model with effective meson-exchange potentials

    SciTech Connect

    Fujiwara, Y.; Nakamoto, C.; Suzuki, Y.

    1996-03-01

    A simultaneous description of the {ital NN} and {ital YN} interactions is attempted in the resonating-group formulation of the spin-flavor SU{sub 6} quark model, in which the full Fermi-Breit interaction with explicit quark-mass dependence acts between quarks, and all the mesons of scalar and pseudo-scalar nonets couple directly to quarks. An overall agreement with the existing data is obtained with few adjustable parameters. In the {Lambda}{ital p} elastic total cross sections, the cusp structure at the {Sigma}{ital N} threshold is strongly enhanced by the antisymmetric {ital LS}{sup ({minus})} force generated from the Fermi-Breit interaction. {copyright} {ital 1996 The American Physical Society.}

  6. Writing job descriptions.

    PubMed

    Schaffner, M

    1990-01-01

    The skill of writing job descriptions begins with an understanding of the advantages, as well as the basic elements, of a well written description. The end result should be approved and updated as needed. Having a better understanding of this process makes writing the job description a challenge rather than a chore.

  7. Nonadiabatic, momentum-dependent, and energy-dependent corrections in the effective-potential description for low-energy scattering of spinless systems - Their relations and validity

    NASA Technical Reports Server (NTRS)

    Au, C. K.

    1988-01-01

    In the effective-potential description for low-energy scattering involving a spinless complex (a body with internal structure), the nonadiabatic corrections are sometimes disguised in momentum-dependent terms. These are distinct from energy-dependent corrections. A general procedure is given here by which all the momentum-dependent corrections can be converted into nonadiabatic corrections in truly local form. Circumstances under which an expansion of the effective potential, in terms of the adiabatic term plus nonadiabatic and energy-dependent corrections is allowed and forbidden, are discussed. An example for the latter is in the case of near degeneracy in the spectrum of the complex or in the extrapolation of the effective potential to short-distance behavior. This indicates that certain claims of 'saturation effect' at short distances in low-energy electron-atom scattering are invalid.

  8. One-electron reduction of tris(2,2 prime -bipyrimidine)ruthenium(2+) ion in aqueous solution. A photochemical, radiation chemical, and electrochemical study

    SciTech Connect

    Neshvad, G.; Hoffman, M.Z. ); Mulazzani, Q.G.; Ciano, M.; D'Angelantonio, M. ); Venturi, M. Univ. di Bologna )

    1989-08-10

    The reduction of Ru(bpm){sub 3}{sup 2+} in aqueous solution has been investigated by use of photochemical, radiation chemical, and electrochemical techniques. The luminescent excited state of the substrate, *Ru(bpm){sub 3}{sup 2+}, has a lifetime ({tau}{sub 0}) of 0.081 {mu}s and a standard reduction potential of {approximately} 1.2 V; it is quenched by electron donors (D) such as ethylenediaminetetraacetic acid (EDTA), triethanolamine (TEOA), ascorbate ion, deprotonated cysteine, and reduced glutathione with values of k{sub q} that depend on the pH of the solution and the reducing ability of the quencher. The one-electron-reduced species, Ru(bpm){sub 3}{sup +}, is formed in the quenching reaction; it is also produced electrochemically and from the reaction of radiolytically generated CO{sub 2}{sup {center dot}{minus}} with Ru(bpm){sub 3}{sup 2+} (k = 6.7 {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}). Ru(bpm){sub 3}{sup +} is a good reducing agent (E{sub ox}{sup 0} = 0.73 V) and reduces MV{sup 2+} (methylviologen) to MV{sup {center dot}+} (k = 1.0 {times} 10{sup 9} M{sup {minus}1} s{sup {minus}1}). Ru(bpm){sub 3}{sup +} also undergoes protonation; its acidic form (pK{sub a} 6.3) is a milder reducing agent (E{sub ox}{sup 0} = 0.50 V) but is still capable of reducing MV{sup 2+} (k = 1.0 {times} 10{sup 6} M{sup {minus}1} s{sup {minus}1}). Both forms of Ru(bpm){sub 3}{sup +} are unstable with respect to long-term storage; it is likely they engage in disproportionation and/or reaction with the solvent. The continuous photolysis of a solution containing Ru(bpm){sub 3}{sup 2+}, MV{sup 2+}, and a sacrificial reductive quencher (EDTA, TEOA) generates MV{sup {center dot}+}. Values of {eta}{sub ce} of 0.64 and {approximately}0.7 for TEOA and EDTA, respectively, in alkaline solution have been obtained.

  9. The structure of a one-electron oxidized Mn(iii)-bis(phenolate)dipyrrin radical complex and oxidation catalysis control via ligand-centered redox activity.

    PubMed

    Lecarme, Laureline; Chiang, Linus; Moutet, Jules; Leconte, Nicolas; Philouze, Christian; Jarjayes, Olivier; Storr, Tim; Thomas, Fabrice

    2016-10-18

    The tetradentate ligand dppH3, which features a half-porphyrin and two electron-rich phenol moieties, was prepared and chelated to manganese. The mononuclear Mn(iii)-dipyrrophenolate complex 1 was structurally characterized. The metal ion lies in a square pyramidal environment, the apical position being occupied by a methanol molecule. Complex 1 displays two reversible oxidation waves at 0.00 V and 0.47 V vs. Fc(+)/Fc, which are assigned to ligand-centered processes. The one-electron oxidized species 1+ SbF6- was crystallized, showing an octahedral Mn(iii) center with two water molecules coordinated at both apical positions. The bond distance analysis and DFT calculations disclose that the radical is delocalized over the whole aromatic framework. Complex 1+ SbF6- exhibits an Stot = 3/2 spin state due to the antiferromagnetic coupling between Mn(iii) and the ligand radical. The zero field splitting parameters are D = 1.6 cm(-1), E/D = 0.18(1), g⊥ = 1.99 and g∥ = 1.98. The dication 12+ is an integer spin system, which is assigned to a doubly oxidized ligand coordinated to a Mn(iii) metal center. Both 1 and 1+ SbF6- catalyze styrene oxidation in the presence of PhIO, but the nature of the main reaction product is different. Styrene oxide is the main reaction product when using 1, but phenylacetaldehyde is formed predominantly when using 1+ SbF6-. We examined the ability of complex 1+ SbF6- to catalyze the isomerization of styrene oxide and found that it is an efficient catalyst for the anti-Markovnikov opening of styrene oxide. The formation of phenylacetaldehyde from styrene therefore proceeds in a tandem E-I (epoxidation-isomerization) mechanism in the case of 1+ SbF6-. This is the first evidence of control of the reactivity for styrene oxidation by changing the oxidation state of a catalyst based on a redox-active ligand.

  10. Older Adults’ Pain Descriptions

    PubMed Central

    McDonald, Deborah Dillon

    2008-01-01

    The purpose of this study was to describe the types of pain information described by older adults with chronic osteoarthritis pain. Pain descriptions were obtained from older adults’ who participated in a posttest only double blind study testing how the phrasing of healthcare practitioners’ pain questions affected the amount of communicated pain information. The 207 community dwelling older adults were randomized to respond to either the open-ended or closed-ended pain question. They viewed and orally responded to a computer displayed videotape of a practitioner asking them the respective pain question. All then viewed and responded to the general follow up question, ““What else can you tell me?” and lastly, “What else can you tell me about your pain, aches, soreness or discomfort?” Audio-taped responses were transcribed and content analyzed by trained, independent raters using 16 a priori criteria from the American Pain Society (2002) Guidelines for the Management of Pain in Osteoarthritis, Rheumatoid Arthritis, and Juvenile Chronic Arthritis. Older adults described important but limited types of information primarily about pain location, timing, and intensity. Pain treatment information was elicited after repeated questioning. Therefore, practitioners need to follow up older adults’ initial pain descriptions with pain questions that promote a more complete pain management discussion. Routine use of a multidimensional pain assessment instrument that measures information such as functional interference, current pain treatments, treatment effects, and side effects would be one way of insuring a more complete pain management discussion with older adults. PMID:19706351

  11. Multimedia content description framework

    NASA Technical Reports Server (NTRS)

    Bergman, Lawrence David (Inventor); Kim, Michelle Yoonk Yung (Inventor); Li, Chung-Sheng (Inventor); Mohan, Rakesh (Inventor); Smith, John Richard (Inventor)

    2003-01-01

    A framework is provided for describing multimedia content and a system in which a plurality of multimedia storage devices employing the content description methods of the present invention can interoperate. In accordance with one form of the present invention, the content description framework is a description scheme (DS) for describing streams or aggregations of multimedia objects, which may comprise audio, images, video, text, time series, and various other modalities. This description scheme can accommodate an essentially limitless number of descriptors in terms of features, semantics or metadata, and facilitate content-based search, index, and retrieval, among other capabilities, for both streamed or aggregated multimedia objects.

  12. Kaluza's kinetic theory description of the classical Hall effect in a single component dilute gas within the Chapman-Enskog approximation

    NASA Astrophysics Data System (ADS)

    Sandoval-Villalbazo, A.; Garcia-Perciante, A. L.; Sagaceta-Mejia, A. R.

    2015-11-01

    Kinetic theory is used to establish the explicit form of the particle flux associated to the Hall effect for the case of a dilute single component charged gas, using the Chapman-Enskog method and the BGK approximation for the collision Kernel. It is shown that when the system evolves towards mechanical equilibrium, the standard treatment using the concept of external force fails to describe the Hall effect. It is also shown that the use of a five-dimensional curved space-time in the description of the dynamics of the charged particle in the kinetic treatment (Kaluza's theory) formally solves the problem. The implications of this result are briefly discussed. The authors acknowledge support from CONACyT (Mexico) through grant CB2011/167563.

  13. YUCCA MOUNTAIN SITE DESCRIPTION

    SciTech Connect

    A.M. Simmons

    2004-04-16

    The ''Yucca Mountain Site Description'' summarizes, in a single document, the current state of knowledge and understanding of the natural system at Yucca Mountain. It describes the geology; geochemistry; past, present, and projected future climate; regional hydrologic system; and flow and transport within the unsaturated and saturated zones at the site. In addition, it discusses factors affecting radionuclide transport, the effect of thermal loading on the natural system, and tectonic hazards. The ''Yucca Mountain Site Description'' is broad in nature. It summarizes investigations carried out as part of the Yucca Mountain Project since 1988, but it also includes work done at the site in earlier years, as well as studies performed by others. The document has been prepared under the Office of Civilian Radioactive Waste Management quality assurance program for the Yucca Mountain Project. Yucca Mountain is located in Nye County in southern Nevada. The site lies in the north-central part of the Basin and Range physiographic province, within the northernmost subprovince commonly referred to as the Great Basin. The basin and range physiography reflects the extensional tectonic regime that has affected the region during the middle and late Cenozoic Era. Yucca Mountain was initially selected for characterization, in part, because of its thick unsaturated zone, its arid to semiarid climate, and the existence of a rock type that would support excavation of stable openings. In 1987, the United States Congress directed that Yucca Mountain be the only site characterized to evaluate its suitability for development of a geologic repository for high-level radioactive waste and spent nuclear fuel.

  14. A Qualitative Descriptive Study of Perceived Sexual Effects of Club Drug Use in Gay and Bisexual Men

    PubMed Central

    Palamar, Joseph J.; Kiang, Mathew V.; Storholm, Erik D.; Halkitis, Perry N.

    2013-01-01

    Club drug use is often associated with unsafe sexual practices and use remains prevalent among gay and bisexual men. Although epidemiological studies commonly report the risk of engaging in unsafe sex due to the effects of particular club drugs, there remain gaps in the literature regarding the specific sexual effects of such substances and the context for their use in this population. We examined secondary data derived from interviews with 198 club drug using gay and bisexual males in New York City and qualitatively describe subjective sexual effects of five drugs: ecstasy, GHB, ketamine, powder cocaine and methamphetamine. Differences and commonalities across the five drugs were examined. Results suggest that each drug tends to provide: 1) unique sexual effects, 2) its own form of disinhibition, and 3) atypical sexual choices, often described as “lower sexual standards.” Differences across drugs emerged with regard to social, sensual and sexual enhancement, sexual interest, and impotence. Although some common perceived sexual effects exist across drugs, the wide variation in these effects suggests different levels of risk and may further suggest varying motivations for using each substance. This study seeks to educate public health officials regarding the sexual effects of club drug use in this population. PMID:24883174

  15. Mathematical description of drug movement into tumor with EPR effect and estimation of its configuration for DDS.

    PubMed

    Hara, Toshihide; Iriyama, Satoshi; Makino, Kimiko; Terada, Hiroshi; Ohya, Masanori

    2010-01-01

    It is known that Drug Delivery System (DDS) is useful to remedy against tumors for the reduction of side effects and the effective dosage. However the shape, in particular, the size of drug (medicine) is empirically decided in the present stage, which will be related to a question how much medicine should be dosed. Taking a particular reaction of tumor tissues called the EPR effect into consideration, we try to mathematically describe the behavior (dynamics) of drug in blood vessel by applying several techniques used in mathematics and physics. In this paper, we estimate the configuration of drug which is most effective to remedy for tumors under various conditions. As a result, this model and its simulation will be useful to design the drug in nano-level.

  16. Descriptive Metadata: Emerging Standards.

    ERIC Educational Resources Information Center

    Ahronheim, Judith R.

    1998-01-01

    Discusses metadata, digital resources, cross-disciplinary activity, and standards. Highlights include Standard Generalized Markup Language (SGML); Extensible Markup Language (XML); Dublin Core; Resource Description Framework (RDF); Text Encoding Initiative (TEI); Encoded Archival Description (EAD); art and cultural-heritage metadata initiatives;…

  17. Physics 3204. Course Description.

    ERIC Educational Resources Information Center

    Newfoundland and Labrador Dept. of Education.

    A description of the physics 3204 course in Newfoundland and Labrador is provided. The description includes: (1) statement of purpose, including general objectives of science education; (2) a list of six course objectives; (3) course content for units on sound, light, optical instruments, electrostatics, current electricity, Michael Faraday and…

  18. Descriptive Metadata: Emerging Standards.

    ERIC Educational Resources Information Center

    Ahronheim, Judith R.

    1998-01-01

    Discusses metadata, digital resources, cross-disciplinary activity, and standards. Highlights include Standard Generalized Markup Language (SGML); Extensible Markup Language (XML); Dublin Core; Resource Description Framework (RDF); Text Encoding Initiative (TEI); Encoded Archival Description (EAD); art and cultural-heritage metadata initiatives;…

  19. Physics 3204. Course Description.

    ERIC Educational Resources Information Center

    Newfoundland and Labrador Dept. of Education.

    A description of the physics 3204 course in Newfoundland and Labrador is provided. The description includes: (1) statement of purpose, including general objectives of science education; (2) a list of six course objectives; (3) course content for units on sound, light, optical instruments, electrostatics, current electricity, Michael Faraday and…

  20. A bioelectrochemical method for the quantitative description of the Hofmeister effect of ionic liquids in aqueous solution.

    PubMed

    Lu, Lu; Hu, Yan; Huang, Xirong; Qu, Yinbo

    2012-09-13

    It is imperative to establish a simple, efficient, and practical method to investigate the Hofmeister effect of ionic liquids (ILs) on the behavior of proteins (enzymes). In this study, the effects of the cations and anions of different ILs in aqueous media on the structural stability of horseradish peroxidase (HRP), a model oxidoreductase, were systematically investigated using electrochemical methods. It is found that without ILs no direct electron transfer current signals of HRP appear at bare glassy carbon electrode (GCE) in phosphate buffer (pH 7.0) even after incubation and accumulation at a negative potential. In the presence of ILs, however, a current signal occurs at GCE, depending on the structure of the IL and its concentration. A linear relationship between the peak currents and the scan rates demonstrates that the direct electron transfer is a surface-confined thin-layer electrochemical process. The redox signal at GCE is from the heme of HRP. An IL has a perturbing effect on the HRP structure. The anodic peak current of HRP at GCE, the catalytic activity of HRP, and the secondary structure of HRP are well correlated. Different cations or anions at varied concentrations have different effects on the structural stability of HRP, resulting in different current signals at GCE. Thus, the anodic peak current of HRP at GCE can be used as an indicator to quantitatively characterize the effect of ILs on the structural stability of HRP. The present Hofmeister series for cations and anions is in good agreement with that reported elsewhere. To our knowledge, this is a first attempt to establish a simple and practical electrochemical method to correlate Hofmeister effects with characteristics of ions and solvents. The present investigation not only deepens our understanding of the complex electrochemical behavior of proteins in ILs media but also offers a practical guidance to designing "green" and biocompatible ILs for protein (enzyme) separation, purification

  1. A Descriptive Study of the Effects of Mentoring and Induction Programs on Novice Teacher Self-Efficacy Beliefs

    ERIC Educational Resources Information Center

    Ackermann, John M.

    2012-01-01

    This study examined the effects of mentoring and induction programs on the self-efficacy beliefs of novice teachers. As school districts in Pennsylvania attempt to maintain highly qualified staff in all curricular areas, supporting newly hired teachers is at the forefront of educational policy in the United States. Beyond training novice teachers,…

  2. Effect Sizes as Result Interpretation Aids in Single-Subject Experimental Research: Description and Application of Four Nonoverlap Methods

    ERIC Educational Resources Information Center

    Rakap, Salih

    2015-01-01

    Single-subject experimental research (SSER), one of the most commonly used research methods in special education and applied behaviour analysis, is a scientific, rigorous and valid method to evaluate the effectiveness of behavioural, educational and psychological treatments. However, studies using single-subject experimental research designs are…

  3. Effect Sizes as Result Interpretation Aids in Single-Subject Experimental Research: Description and Application of Four Nonoverlap Methods

    ERIC Educational Resources Information Center

    Rakap, Salih

    2015-01-01

    Single-subject experimental research (SSER), one of the most commonly used research methods in special education and applied behaviour analysis, is a scientific, rigorous and valid method to evaluate the effectiveness of behavioural, educational and psychological treatments. However, studies using single-subject experimental research designs are…

  4. Elementary Bilingual and ESL Education Programs and Their Effectiveness within Schools. A Descriptive Study, Teaching Methods, and Strategies.

    ERIC Educational Resources Information Center

    Perez, Cassandra Leigh; Karr-Kidwell, PJ

    The purpose of this report was to collect a summary of information on instructional programs for bilingual students in Irving Independepent School District (Texas), so the parents of these students as well as staff members could evaluate the existing bilingual programs. The effectiveness of improving English-as-a-Second-Language skills for…

  5. Diagnostic model for equatorial spread F. 1. Model description and application to electric field and neutral wind effects

    SciTech Connect

    Maruyama, T.

    1988-12-01

    Linear growth rates for the gravitational Rayleigh-Taylor instability are calculated using the ionospheric electron density distribution obtained by solving the ion continuity equations including dynamics for O/sup +/, NO/sup +/, O/sub 2//sup +/, and N/sup +//sub 2/ ions. The instability model includes the contributions from plasma away from the magnetic equatorial plane. Effects of the transequatorial component of the thermospheric wind and the E x B drift are investigated. Thermospheric winds are based on theoretical calculations. The E x B drift velocities are modeled after the observations at Jicamarca and Fortaleza for different seasons. The results have shown that both effects are equally important to controlling the occurrence of equatorial spread F. Observed winter-summer asymmetry of the occurrence probability at the Jicamarca longitude is explained by the characteristics of the E x B drift velocity model. However, in the case of Fortaleza, the observations cannot be explained strictly in terms of the E x B drift effect and the wind effect, we have obtained a qualitative agreement between the observations and calculations over all seasons for both Jicamarca and Fortaleza. copyright American Geophysical Union 1988

  6. Causal Aspects of Social Capital of Iranian Patients with Cancer: Evidence of Predictive, Modifying and Descriptive Effects in Health Inequality.

    PubMed

    Tavakol, Mohamad; Naserirad, Mohsen

    2013-10-01

    There is a good literature confirming the effects of social capital on different health domains. The increase in different types of cancer has caused scientists to encounter a number of issues regarding the reasons of affliction by this disease. The aim of this empirical research was to study the causal aspects of social capital of Iranian patients with cancer. The study was a causal-comparative study conducted in the spring and summer of 2010 in Tehran. The sample consists of 212 people selected based on affliction or no affliction to cancer. Social capital emphasizes two dimensions of structure and cognition. Social participation, social trust and sense of social solidarity are considered as different dimensions of social capital. The focus has been on personal social capital. The effect and association of social capital are not significant with any of stomach and colon cancers. The effect and association of social trust are not significant with any of stomach, colon and breast cancers. People with similar social capital in their life have different experiences of cancer-related stress and unhealthy behaviors. Thus a specific feature of a stressful social determinant is not a reliable criterion to determine the degree of stress and the extent of its effect on affliction to cancer.

  7. A Descriptive Study of the Effects of Mentoring and Induction Programs on Novice Teacher Self-Efficacy Beliefs

    ERIC Educational Resources Information Center

    Ackermann, John M.

    2012-01-01

    This study examined the effects of mentoring and induction programs on the self-efficacy beliefs of novice teachers. As school districts in Pennsylvania attempt to maintain highly qualified staff in all curricular areas, supporting newly hired teachers is at the forefront of educational policy in the United States. Beyond training novice teachers,…

  8. Shallow groundwater effect on land surface temperature and surface energy balance under bare soil conditions: modeling and description

    USDA-ARS?s Scientific Manuscript database

    Appreciating when and how groundwater affects surface temperature and energy fluxes is important for utilizing remote sensing in groundwater studies and for integrating aquifers within land surface models. To explore the shallow groundwater effect, we numerically exposed two soil profiles – one havi...

  9. Microgravity Environment Description Handbook

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard; McPherson, Kevin; Hrovat, Kenneth; Moskowitz, Milton; Rogers, Melissa J. B.; Reckart, Timothy

    1997-01-01

    The Microgravity Measurement and Analysis Project (MMAP) at the NASA Lewis Research Center (LeRC) manages the Space Acceleration Measurement System (SAMS) and the Orbital Acceleration Research Experiment (OARE) instruments to measure the microgravity environment on orbiting space laboratories. These laboratories include the Spacelab payloads on the shuttle, the SPACEHAB module on the shuttle, the middeck area of the shuttle, and Russia's Mir space station. Experiments are performed in these laboratories to investigate scientific principles in the near-absence of gravity. The microgravity environment desired for most experiments would have zero acceleration across all frequency bands or a true weightless condition. This is not possible due to the nature of spaceflight where there are numerous factors which introduce accelerations to the environment. This handbook presents an overview of the major microgravity environment disturbances of these laboratories. These disturbances are characterized by their source (where known), their magnitude, frequency and duration, and their effect on the microgravity environment. Each disturbance is characterized on a single page for ease in understanding the effect of a particular disturbance. The handbook also contains a brief description of each laboratory.

  10. A phenomenological relative biological effectiveness approach for proton therapy based on an improved description of the mixed radiation field

    NASA Astrophysics Data System (ADS)

    Mairani, A.; Dokic, I.; Magro, G.; Tessonnier, T.; Bauer, J.; Böhlen, T. T.; Ciocca, M.; Ferrari, A.; Sala, P. R.; Jäkel, O.; Debus, J.; Haberer, T.; Abdollahi, A.; Parodi, K.

    2017-02-01

    Proton therapy treatment planning systems (TPSs) are based on the assumption of a constant relative biological effectiveness (RBE) of 1.1 without taking into account the found in vitro experimental variations of the RBE as a function of tissue type, linear energy transfer (LET) and dose. The phenomenological RBE models available in literature are based on the dose-averaged LET (LET D ) as an indicator of the physical properties of the proton radiation field. The LET D values are typically calculated taking into account primary and secondary protons, neglecting the biological effect of heavier secondaries. In this work, we have introduced a phenomenological RBE approach which considers the biological effect of primary protons, and of secondary protons, deuterons, tritons (Z  =  1) and He fragments (3He and 4He, Z  =  2). The calculation framework, coupled with a Monte Carlo (MC) code, has been successfully benchmarked against clonogenic in vitro data measured in this work for two cell lines and then applied to determine biological quantities for spread-out Bragg peaks and a prostate and a head case. The introduced RBE formalism, which depends on the mixed radiation field, the dose and the ratio of the linear-quadratic model parameters for the reference radiation {{≤ft(α /β \\right)}\\text{ph}} , predicts, when integrated in an MC code, higher RBE values in comparison to LET D -based parameterizations. This effect is particular enhanced in the entrance channel of the proton field and for low {{≤ft(α /β \\right)}\\text{ph}} tissues. For the prostate and the head case, we found higher RBE-weighted dose values up to about 5% in the entrance channel when including or neglecting the Z  =  2 secondaries in the RBE calculation. TPSs able to proper account for the mixed radiation field in proton therapy are thus recommended for an accurate determination of the RBE in the whole treatment field.

  11. A phenomenological relative biological effectiveness approach for proton therapy based on an improved description of the mixed radiation field.

    PubMed

    Mairani, A; Dokic, I; Magro, G; Tessonnier, T; Bauer, J; Böhlen, T T; Ciocca, M; Ferrari, A; Sala, P R; Jäkel, O; Debus, J; Haberer, T; Abdollahi, A; Parodi, K

    2017-02-21

    Proton therapy treatment planning systems (TPSs) are based on the assumption of a constant relative biological effectiveness (RBE) of 1.1 without taking into account the found in vitro experimental variations of the RBE as a function of tissue type, linear energy transfer (LET) and dose. The phenomenological RBE models available in literature are based on the dose-averaged LET (LET D ) as an indicator of the physical properties of the proton radiation field. The LET D values are typically calculated taking into account primary and secondary protons, neglecting the biological effect of heavier secondaries. In this work, we have introduced a phenomenological RBE approach which considers the biological effect of primary protons, and of secondary protons, deuterons, tritons (Z  =  1) and He fragments ((3)He and (4)He, Z  =  2). The calculation framework, coupled with a Monte Carlo (MC) code, has been successfully benchmarked against clonogenic in vitro data measured in this work for two cell lines and then applied to determine biological quantities for spread-out Bragg peaks and a prostate and a head case. The introduced RBE formalism, which depends on the mixed radiation field, the dose and the ratio of the linear-quadratic model parameters for the reference radiation [Formula: see text], predicts, when integrated in an MC code, higher RBE values in comparison to LET D -based parameterizations. This effect is particular enhanced in the entrance channel of the proton field and for low [Formula: see text] tissues. For the prostate and the head case, we found higher RBE-weighted dose values up to about 5% in the entrance channel when including or neglecting the Z  =  2 secondaries in the RBE calculation. TPSs able to proper account for the mixed radiation field in proton therapy are thus recommended for an accurate determination of the RBE in the whole treatment field.

  12. Effectiveness of muscle strengthening and description of protocols for preventing falls in the elderly: a systematic review

    PubMed Central

    Ishigaki, Erika Y.; Ramos, Lidiane G.; Carvalho, Elisa S.; Lunardi, Adriana C.

    2014-01-01

    Background Falls are a geriatric syndrome that is considered a significant public health problem in terms of morbidity and mortality because they lead to a decline in functional capacity and an impaired quality of life in the elderly. Lower limb muscle strengthening seems to be an effective intervention for preventing falls; however, there is no consensus regarding the best method for increasing lower limb muscle strength. Objectives To analyze the effectiveness of lower limb muscle strengthening and to investigate and describe the protocols used for preventing falls in elderly subjects. Method We performed a systematic review of randomized and controlled clinical trials published between 2002 and 2012 in the databases PubMed, EMBASE, Scopus, Web of Science, and PEDro that cited some type of lower limb muscle strengthening protocol and that evaluated the incidence of falls as the primary outcome exclusively in elderly subjects. Twelve studies met the inclusion criteria. Qualitative analysis was performed by independent reviewers applying the PEDro scale. Results The data obtained from the selected studies showed lower fall rates in the intervention groups compared to controls. Six studies described the lower limb muscle strengthening protocol in detail. High methodological quality was found in 6 studies (PEDro score ≥7/10 points). Conclusions The methodological quality of the studies in this area appears to leave little doubt regarding the effectiveness of lower limb strengthening exercises for preventing falls in elderly subjects, however the interventions in these studies were poorly reported. PMID:24760166

  13. Effect of Na+ and Ca2+ ions on a lipid Langmuir monolayer: an atomistic description by molecular dynamics simulations.

    PubMed

    Giner Casares, Juan José; Camacho, Luis; Martín-Romero, Maria Teresa; López Cascales, José Javier

    2008-12-01

    Studying the effect of alkali and alkaline-earth metal cations on Langmuir monolayers is relevant from biophysical and nanotechnological points of view. In this work, the effect of Na(+) and Ca(2+) on a model of an anionic Langmuir lipid monolayer of dimyristoylphosphatidate (DMPA(-)) is studied by molecular dynamics simulations. The influence of the type of cation on lipid structure, lipid-lipid interactions, and lipid ordering is analyzed in terms of electrostatic interactions. It is found that for a lipid monolayer in its solid phase, the effect of the cations on the properties of the lipid monolayer can be neglected. The influence of the cations is enhanced for the lipid monolayer in its gas phase, where sodium ions show a high degree of dehydration compared with calcium ions. This loss of hydration shell is partly compensated by the formation of lipid-ion-lipid bridges. This difference is ascribed to the higher charge-to-radius ratio q/r for Ca(2+), which makes ion dehydration less favorable compared to Na(+). Owing to the different dehydration behavior of sodium and calcium ions, diminished lipid-lipid coordination, lipid-ion coordination, and lipid ordering are observed for Ca(2+) compared to Na(+). Furthermore, for both gas and solid phases of the lipid Langmuir monolayers, lipid conformation and ion dehydration across the lipid/water interface are studied.

  14. How consumers are affected by product descriptions in online shopping: Event-related potentials evidence of the attribute framing effect.

    PubMed

    Jin, Jia; Zhang, Wuke; Chen, Mingliang

    2017-07-20

    Due to the limitations of the human ability to process information, e-consumers' decisions are likely to be influenced by various cognitive biases, such as the attribute framing effect. This effect has been well studied by numerous scholars; however, the associated underlying neural mechanisms with a critical temporal resolution have not been revealed. Thus, this study applies the measurement of event-related potentials (ERPs) to directly examine the role of attribute framing in information processing and decision-making in online shopping. The behavioral results showed that participants demonstrated a higher purchase intention with a shorter reaction time under a positive framing condition compared to participants under a negative framing condition. Compared with positive framing messages, the results of ERPs indicated that negative framing messages attracted more attention resources at the early stage of rapid automatic processing (larger P2 amplitude) and resulted in greater cognitive conflict and decision difficulty (larger P2-N2 complex). Moreover, compared with negative messages, positive framing messages allowed consumers to perceive a better future performance of products and classify these products as a categorization of higher evaluation (larger LPP amplitude) at the late cognitive processing stage of evaluation. Based on these results, we provide evidence for a better understanding of how different attribute framing messages are processed and ultimately lead to the framing effect. Copyright © 2017 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  15. Microwave ablation of the liver: a description of lesion evolution over time and an investigation of the heat sink effect.

    PubMed

    Bhardwaj, N; Dormer, J; Ahmad, F; Strickland, A D; Gravante, G; West, K; Dennison, A R; Lloyd, D M

    2011-12-01

    Microwave ablation has been successfully used to treat unresectable liver tumours for many years. However, despite its widespread use, there seems to be a relative paucity of experimental data regarding lesion evolution and the effects of any surrounding vasculature on ablation morphology. The aim of this study was to investigate the principal pathological changes in the liver following microwave ablation, in particular the heat sink effect. In addition we carefully reviewed the available literature to provide an overview of all relevant pathological studies. Microwave ablation was carried out on male rats at various distances from the hilum. Histological (H&E) and immunocytochemical (caspase 3) analyses of the lesion were performed at various time points; 0, 4, 24, 48  hours, 2 weeks and 1 month. A literature review was carried out using Medline, Embase and the Cochrane database to identify all relevant histological studies. The lesion underwent complete coagulative necrosis and was extremely regular at the ablation edge with no evidence of any influence from surrounding blood vessels at all time points. H&E and caspase 3 results were consistent and microwave caused little collateral damage outside the intended ablation zone. This study suggests that microwave ablation is extremely concise and is minimally affected by the heat sink effect. Comparative investigations with other treatment modalities are required.

  16. Short and long term health effects of parental tobacco smoking during pregnancy and lactation: a descriptive review.

    PubMed

    Banderali, G; Martelli, A; Landi, M; Moretti, F; Betti, F; Radaelli, G; Lassandro, C; Verduci, E

    2015-10-15

    A great deal of attention has been focused on adverse effects of tobacco smoking on conception, pregnancy, fetal, and child health. The aim of this paper is to discuss the current evidence regarding short and long-term health effects on child health of parental smoking during pregnancy and lactation and the potential underlying mechanisms. Studies were searched on MEDLINE(®) and Cochrane database inserting, individually and using the Boolean ANDs and ORs, 'pregnancy', 'human lactation', 'fetal growth', 'metabolic outcomes', 'obesity', 'cardiovascular outcomes', 'blood pressure', 'brain development', 'respiratory outcomes', 'maternal or paternal or parental tobacco smoking', 'nicotine'. Publications coming from the reference list of studies were also considered from MEDLINE. All sources were retrieved between 2015-01-03 and 2015-31-05. There is overall consistency in literature about negative effects of fetal and postnatal exposure to parental tobacco smoking on several outcomes: preterm birth, fetal growth restriction, low birth weight, sudden infant death syndrome, neurodevelopmental and behavioral problems, obesity, hypertension, type 2 diabetes, impaired lung function, asthma and wheezing. While maternal smoking during pregnancy plays a major role on adverse postnatal outcomes, it may also cumulate negatively with smoking during lactation and with second-hand smoking exposure. Although this review was not strictly designed as a systematic review and the PRISMA Statement was not fully applied it may benefit the reader with a promptly and friendly readable update of the matter. This review strengthens the need to plan population health policies aimed to implement educational programs to hopefully minimize tobacco smoke exposure during pregnancy and lactation.

  17. Description and evaluation of the effects of urban and agricultural development on the surficial aquifer system, Palm Beach County, Florida

    USGS Publications Warehouse

    Miller, W.L.

    1988-01-01

    The surficial aquifer system in Palm Beach County was studied during 1982-85 to determine the effects of increased urban and agricultural development on groundwater levels, flow directions, and quality. The surficial aquifer system and its geologic matrix are divisible into three zones on the bases of relative permeabilities and lithologic characteristics. The two greatest water users in the county, public supply utilities and agricultural irrigators, increased total water withdrawals by 123 and 50%, respectively, during 1970-80. By 1980, 76% of public supply withdrawals were from zones I and II of the surficial aquifer system, whereas groundwater pumpage for irrigation decreased to 9% of the total irrigation water used. Increases in groundwater withdrawals for public supply were greatest in the southeast and central coastal parts of the county and served as an indicator for potential changes of flow directions and water quality in the surficial aquifer system. Residual seawater, emplaced in the aquifer system during the Pleistocene Epoch, is still prevalent in the central and western parts of Palm Beach County where low permeabilities in the geologic matrix have retarded its dilution. Chemical analyses of canal-water and groundwater samples collected in April 1984 were used to evaluate the effects of groundwater/surface water exchange on the quality of water during canal conveyance across the area containing residual seawater. (USGS)

  18. Pharmacogenetic study of second-generation antipsychotic long-term treatment metabolic side effects (the SLiM Study): rationale, objectives, design and sample description.

    PubMed

    Pina-Camacho, Laura; Díaz-Caneja, Covadonga M; Saiz, Pilar A; Bobes, Julio; Corripio, Iluminada; Grasa, Eva; Rodriguez-Jimenez, Roberto; Fernández, Miryam; Sanjuán, Julio; García-López, Aurelio; Tapia-Casellas, Cecilia; Álvarez-Blázquez, María; Fraguas, David; Mitjans, Marina; Arias, Bárbara; Arango, Celso

    2014-01-01

    Weight gain is an important and common side effect of second generation antipsychotics (SGAs). Furthermore, these drugs can induce other side effects associated with higher cardiovascular morbidity and mortality, such as insulin resistance, diabetes or metabolic syndrome. Preliminary studies show that inter-individual genetic differences produce varying degrees of vulnerability to the different SGA-induced side effects. The Second-generation antipsychotic Long-term treatment Metabolic side effects (SLiM) study aims to identify clinical, environmental and genetic factors that explain inter-individual differences in weight gain and metabolic changes in drug-naïve patients after six months of treatment with SGAs. The SLIM study is a multicenter, observational, six-month pharmacogenetic study where a cohort of 307 drug-naïve paediatric and adult patients (age range 8.8-90.1 years) and a cohort of 150 age- and sex- matched healthy controls (7.8-73.2 years) were recruited. This paper describes the rationale, objectives and design of the study and provides a description of the sample at baseline. Results from the SLiM study will provide a better understanding of the clinical, environmental, and genetic factors involved in weight gain and metabolic disturbances associated with SGA treatment. Copyright © 2014 SEP y SEPB. Published by Elsevier España. All rights reserved.

  19. Expanding the Description of Spaceflight Effects beyond Bone Mineral Density [BMD]: Trabecular Bone Score [TBS] in ISS Astronauts

    NASA Technical Reports Server (NTRS)

    Sibonga, J. D.; Spector, E. R.; King, L. J.; Evans, H. J.; Smith, S. A.

    2014-01-01

    Dual-energy x-ray absorptiometry [DXA] is the widely-applied bone densitometry method used to diagnose osteoporosis in a terrestrial population known to be at risk for age-related bone loss. This medical test, which measures areal bone mineral density [aBMD] of clinically-relevant skeletal sites (e.g., hip and spine), helps the clinician to identify which persons, among postmenopausal women and men older than 50 years, are at high risk for low trauma or fragility fractures and might require an intervention. The most recognized osteoporotic fragility fracture is the vertebral compression fracture which can lead to kyphosis or hunched backs typically seen in the elderly. DXA measurement of BMD however is recognized to be insufficient as a sole index for assessing fracture risk. DXA's limitation may be related to its inability to monitor changes in structural parameters, such as trabecular vs. cortical bone volumes, bone geometry or trabecular microarchitecture. Hence, in order to understand risks to human health and performance due to space exposure, NASA needs to expand its measurements of bone to include other contributors to skeletal integrity. To this aim, the Bone and Mineral Lab conducted a pilot study for a novel measurement of bone microarchitecture that can be obtained by retrospective analysis of DXA scans. Trabecular Bone Score (TBS) assesses changes to trabecular microarchitecture by measuring the grey color "texture" information extracted from DXA images of the lumbar spine. An analysis of TBS in 51 ISS astronauts was conducted to assess if TBS could detect 1) an effect of spaceflight and 2) a response to countermeasures independent of DXA BMD. In addition, changes in trunk body lean tissue mass and in trunk body fat tissue mass were also evaluated to explore an association between body composition, as impacted by ARED exercise, and bone microarchitecture. The pilot analysis of 51 astronaut scans of the lumbar spine suggests that, following an ISS

  20. Descriptions of stony meteorites

    NASA Technical Reports Server (NTRS)

    Score, R.; King, T. V. V.; Schwarz, C. M.; Reid, A. M.; Mason, B.

    1982-01-01

    The individual specimens, arranged by class are described. Within the chondrites, the specimens are grouped according to the Van Schmus-Wood classification, and the descriptions follow the order of increasing petrographic type. The original weight of the specimen is given to the nearest gram (nearest 0.1 gram for specimens weighing less than 100 grams). Material on al characterized meteorites collected together with descriptions of some meteorites is included. Specimens weighing less than 100 grams are listed without descriptions, unless they show distinctive features.

  1. Hardware description languages

    NASA Technical Reports Server (NTRS)

    Tucker, Jerry H.

    1994-01-01

    Hardware description languages are special purpose programming languages. They are primarily used to specify the behavior of digital systems and are rapidly replacing traditional digital system design techniques. This is because they allow the designer to concentrate on how the system should operate rather than on implementation details. Hardware description languages allow a digital system to be described with a wide range of abstraction, and they support top down design techniques. A key feature of any hardware description language environment is its ability to simulate the modeled system. The two most important hardware description languages are Verilog and VHDL. Verilog has been the dominant language for the design of application specific integrated circuits (ASIC's). However, VHDL is rapidly gaining in popularity.

  2. Towards a conceptual framework demonstrating the effectiveness of audiovisual patient descriptions (patient video cases): a review of the current literature

    PubMed Central

    2012-01-01

    Background Technological advances have enabled the widespread use of video cases via web-streaming and online download as an educational medium. The use of real subjects to demonstrate acute pathology should aid the education of health care professionals. However, the methodology by which this effect may be tested is not clear. Methods We undertook a literature review of major databases, found relevant articles relevant to using patient video cases as educational interventions, extracted the methodologies used and assessed these methods for internal and construct validity. Results A review of 2532 abstracts revealed 23 studies meeting the inclusion criteria and a final review of 18 of relevance. Medical students were the most commonly studied group (10 articles) with a spread of learner satisfaction, knowledge and behaviour tested. Only two of the studies fulfilled defined criteria on achieving internal and construct validity. The heterogeneity of articles meant it was not possible to perform any meta-analysis. Conclusions Previous studies have not well classified which facet of training or educational outcome the study is aiming to explore and had poor internal and construct validity. Future research should aim to validate a particular outcome measure, preferably by reproducing previous work rather than adopting new methods. In particular cognitive processing enhancement, demonstrated in a number of the medical student studies, should be tested at a postgraduate level. PMID:23256787

  3. The description of an effective sinkhole investigation approach: A case study of two sites in Greene County, Missouri

    NASA Astrophysics Data System (ADS)

    Nwokebuihe, Stanley Chinedu

    Karst topographies pose danger to the environment. The associated gradual subsidence or sudden collapse of the ground can lead to loss of lives and damage to property. A sinkhole is the subsidence or collapse of the overburden into subsurface cavities. Sinkholes develop in different sizes, shapes and rates all over the world especially in areas where the bedrock can be dissolved by percolating slightly acidic surface water. Different methods have been used to investigate sinkholes. Boring is the most common of these methods. But the boring technique is quite inefficient; it only provides information of the subsurface conditions at the boring location thereby requiring multiple borings to more accurately characterize a sinkhole. Geophysical methods have also been used to investigate sinkholes including Gravity, Electromagnetic, Multichannel Analysis of Surface Waves (MASW), Electrical Resistivity Tomography and Ground Penetrating Radar (GPR). But these methods work best in appropriate geological environments in mapping sinkholes. This project describes a framework for an efficient investigation of sinkholes. The study uses the combination of Aerial photographs, Topographic maps, geological maps and cross sections which are categorized as preliminary studies; appropriate geophysical methods (MASW and ERT) and a few borings to effectively characterize sinkholes. This approach was successfully applied in two case study sites located in Greene County, Missouri and is recommended for future sinkhole investigations where applicable.

  4. Towards a conceptual framework demonstrating the effectiveness of audiovisual patient descriptions (patient video cases): a review of the current literature.

    PubMed

    Roland, Damian; Coats, Tim; Matheson, David

    2012-12-21

    Technological advances have enabled the widespread use of video cases via web-streaming and online download as an educational medium. The use of real subjects to demonstrate acute pathology should aid the education of health care professionals. However, the methodology by which this effect may be tested is not clear. We undertook a literature review of major databases, found relevant articles relevant to using patient video cases as educational interventions, extracted the methodologies used and assessed these methods for internal and construct validity. A review of 2532 abstracts revealed 23 studies meeting the inclusion criteria and a final review of 18 of relevance. Medical students were the most commonly studied group (10 articles) with a spread of learner satisfaction, knowledge and behaviour tested. Only two of the studies fulfilled defined criteria on achieving internal and construct validity. The heterogeneity of articles meant it was not possible to perform any meta-analysis. Previous studies have not well classified which facet of training or educational outcome the study is aiming to explore and had poor internal and construct validity. Future research should aim to validate a particular outcome measure, preferably by reproducing previous work rather than adopting new methods. In particular cognitive processing enhancement, demonstrated in a number of the medical student studies, should be tested at a postgraduate level.

  5. Effects of exchange-correlation potentials in density functional descriptions of ground-state and photoionization of fullerenes

    NASA Astrophysics Data System (ADS)

    Choi, Jinwoo; Chang, Eonho; Anstine, Dylan M.; Chakraborty, Himadri

    2016-05-01

    We study the ground state properties of C60 and C240 molecules in a spherical frame of local density approximation (LDA). Within this mean-field theory, two different approximations to the exchange-correlation (xc) functional are used: (i) The Gunnerson-Lundqvist parametrization augmented by a treatment to correct for the electron self-interaction and (ii) the van Leeuwen and Baerends (LB94) model potential that inclusively restores electron's asymptotic properties. Results show differences in the ground-state potential, level energies and electron densities between the two xc choices. We then use the ground structure to find the excited and ionized states of the systems and calculate dipole single-photoionization cross sections in a time-dependent LDA method that incorporates linear-response dynamical correlations. Comparative effects of the choices of xc on collective plasmon and single-excitation Auger resonances as well as on geometry driven cavity oscillations are found significant. The work is supported by the NSF, USA.

  6. Effects of exchange-correlation potentials on the density-functional description of C60 versus C240 photoionization

    NASA Astrophysics Data System (ADS)

    Choi, Jinwoo; Chang, EonHo; Anstine, Dylan M.; Madjet, Mohamed El-Amine; Chakraborty, Himadri S.

    2017-02-01

    We study the photoionization properties of the C60 versus C240 molecule in a spherical jellium frame of the density-functional method. Two prototypical approximations of the exchange-correlation (xc) functional are used: (i) the Gunnarsson-Lundqvist parametrization [Gunnarsson and Lundqvist, Phys. Rev. B 13, 4274 (1976), 10.1103/PhysRevB.13.4274] with a correction for the electron self-interaction (SIC) introduced artificially from the outset and (ii) a gradient-dependent augmentation of approximation (i) using the van Leeuwen and Baerends model potential [van Leeuwen and Baerends, Phys. Rev. A 49, 2421 (1994), 10.1103/PhysRevA.49.2421], in lieu of SIC, that restores electrons' asymptotic properties intrinsically within the formalism. Ground-state results from the two schemes for both molecules show differences in the shapes of mean-field potentials and bound-level properties. The choice of an xc scheme also significantly alters the dipole single-photoionization cross sections obtained by an ab initio method that incorporates linear-response dynamical correlations. Differences in the structures and ionization responses between C60 and C240 uncover the effect of molecular size on the underlying physics. Analysis indicates that the collective plasmon resonances with the gradient-based xc option produce results noticeably closer to the experimental data available for C60.

  7. Description and validation of a method for simultaneous estimation of effective population size and mutation rate from human population data.

    PubMed Central

    Chakraborty, R; Neel, J V

    1989-01-01

    A method is presented for utilizing population data on electrophoretic variants of proteins to estimate simultaneously the effective sizes (Ne values) of the populations in question and the rate of mutation resulting in electromorphs at the loci whose products were surveyed. The method is applied to data from 12 relatively unacculturated Amerindian tribes for whom census data and independent estimates of the number of different electrophoretic variants at 27 loci are available. Because of tribal demographic structure, Ne should be less than the current number of reproductive-aged adults. In fact, it is substantially greater for 7 tribes, most likely due to intertribal migration and a recent decrease in tribal size. Estimates of locus mutation rates for the 27 loci vary by more than a factor of 20, with an average of 1.1 x 10(-5) per locus per generation. This latter estimate is in satisfactory agreement with the results of other indirect approaches to the estimation of mutation rates in these tribes but about two times higher than the results of direct estimates based on these same loci in studies on civilized populations. This discrepancy could be due to the above-hypothesized migration and to decreases in tribal size. PMID:2594777

  8. Vibrational quenching of excitonic splittings in H-bonded molecular dimers: adiabatic description and effective mode approximation.

    PubMed

    Kopec, Sabine; Ottiger, Philipp; Leutwyler, Samuel; Köppel, Horst

    2012-11-14

    The quenching of the excitonic splitting in hydrogen-bonded molecular dimers has been explained recently in terms of exciton coupling theory, involving Förster's degenerate perturbation theoretical approach [P. Ottiger, S. Leutwyler, and H. Köppel, J. Chem. Phys. 136, 174308 (2012)]. Here we provide an alternative explanation based on the properties of the adiabatic potential energy surfaces. In the proper limit, the lower of these surfaces exhibits a double-minimum shape, with an asymmetric distortion that destroys the geometric equivalence of the excitonically coupled monomers. An effective mode is introduced that exactly reproduces the energy gain and amount of distortion that occurs in a multi-dimensional normal coordinate space. This allows to describe the quenched exciton splitting as the energy difference of the two (S(1) and S(2)) vibronic band origins in a one-dimensional (rather than multi-dimensional) vibronic calculation. The agreement with the earlier result (based on Förster theory) is excellent for all five relevant cases studied. A simple rationale for the quenched exciton splitting as nonadiabatic tunneling splitting on the lower double-minimum potential energy surface is given.

  9. [Description of the hemodynamic and respiratory effects of hemoperfusion treatment with polymyxin B in patients with abdominal septic shock].

    PubMed

    Navarro, R; Guerrero, M; González, M; Quecedo, L; García, A; Ramasco, F

    2013-01-01

    The objective of this study is to describe the hemodynamic effects, inotropic and vasoactive drug dependence, and to analyze the PO2/FiO2 ratio in 13 patients with septic shock of abdominal origin after hemoperfusion treatment with polymyxin-B. Treatment with polymyxin hemoperfusion therapy is indicated for patients with severe sepsis/septic shock of abdominal origin who do not respond adequately to conventional therapy. Two complete cycles with polymyxin cartridge were performed on 11 of the 13 patients, and a single cycle on the other O2. After treatment, the mean airway pressure (MAP) was increased (P=.003), the need for norepinephrine decreased (P=.003), and the PO2/FiO2 ratio increased (P=.02). The use of polymyxin hemoperfusion in patients with septic shock of intra-abdominal origin can significantly improve hemodynamic and respiratory functions. Copyright © 2012 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

  10. Effective-medium description of a metasurface composed of a periodic array of nanoantennas coupled to a metallic film

    NASA Astrophysics Data System (ADS)

    Bowen, P. T.; Baron, A.; Smith, D. R.

    2017-03-01

    We compute the reflectance properties of a metasurface that consists of a doubly periodic array of patch nanoantennas strongly coupled to a metallic film. Each plasmonic patch antenna can be accurately modeled as a polarizable, radiating, magnetic dipole. By accounting for interactions amongst the dipoles, an equivalent surface polarizability can be obtained, from which the effective surface impedance, reflectivity, and other homogenized quantities of interest can be obtained. When the metasurface is extremely close to the metal film, the interaction between constituent dipoles is dominated by surface plasmon mediation. We calculate analytically the dipole interaction constant by explicitly evaluating the infinite sum of fields from all the dipoles in the lattice. While a single film-coupled nanoparticle exhibits anomalous loss due to coupling to surface plasmons, we find that for the lattice of dipoles, the radiation reaction force due to the coupling to the surface plasmon modes is exactly canceled by the interaction constant; the lattice thereby conserves energy in the limit of zero Ohmic loss. When Ohmic losses are present, absorption to surface plasmons reemerges and can be compared with the losses to radiation and Ohmic absorption in the metasurface.

  11. Chemical Theory and Computation Special Feature: Static and dynamic quantum effects in molecular liquids: A linearized path integral description of water

    NASA Astrophysics Data System (ADS)

    Aage Poulsen, Jens; Nyman, Gunnar; Rossky, Peter J.

    2005-05-01

    Structure, transport properties, and IR spectra including quantum effects are calculated for a flexible simple point charge model of liquid water. A recently introduced combination of a variational local harmonic description of the liquid potential surface and the classical Wigner approximation for the dynamics is used. The potential energy and interatomic radial distribution functions are in good agreement with accurate results from the literature and are significantly closer to experiment than predictions found from classical theory. The oxygen and hydrogen velocity correlation functions are also calculated, and the corresponding molecular diffusion coefficient is in good accord with existing theoretical estimates including quantum effects. Of most interest, an ab initio quantum correction factor is obtained to correct the far IR spectrum of water. When corrected, a spectrum based on a classical simulation yields results that agree well with experiment. Combined with internal tests of consistency, these observations indicate that this quite flexible approach will be effective for a variety of molecular problems involving the dynamics of light nuclei. computer simulation | liquid dynamics

  12. First description of the effect of a non-sulfonylurea compound, tetramethylpyrazine, on coronary response to desoxyglucose-induced ischemia.

    PubMed

    Grisold, M; Köppel, H; Gasser, R

    1998-01-01

    The compound 2,3,5,6-Tetramethylpyrazine (TMP; Ligustrazine), a flavouring component and sweetness enhancer for beverages constitutes a commonly used food additive. Now we studied the effect of TMP on coronary artery dilation during ischemia: In our experiments we used isolated, Langendorff-perfused guinea pig hearts, arrested with K(+)-rich Normal Tyrode solution (in mM: NaCl 129.5, KCl 15, MgCl2 0.8, CaCl2 1.0, glucose 10), buffered with 10 mM HEPES to pH 7.4 at 37 degrees C, equilibrated with 100% O2. Ischemia was simulated by equimolar replacement of glucose by 2-deoxyglucose (DOG), an inhibitor of oxydative phosphorylation. We found that coronary perfusion pressure (CPP) decreased by 20 +/- 1.2 cm H2O (from initially 90 cm H2O; n = 6, +/- SEM) within 15 min from the onset of DOG. In the presence of 1 mM TMP the decrease in CPP was largely attenuated and CPP declined by 1.4 +/- 1.0 cm H2O (n = 6, +/- SEM; p < 0.01). In 2 out of the 6 TMP experiments even as light increase in CPP (< 2 cm H2O) could be seen. We conclude that TMP, a blocker of ATP-dependent K(+)-channels in pancreatic beta-cells and possibly in arterial smooth muscle cells, prevents coronary dilation in response to ischemia. The possible suppression of this vital mobilization of coronary reserve during ischemia in patients with coronary artery disease certainly merits further attention and may question the use of this compound as a food additive.

  13. Magnetic Resonance Imaging in Psoriatic Arthritis: A Descriptive Study of Indications, Features and Effect on Treatment Change.

    PubMed

    Maldonado-Ficco, Hernán; Sheane, Barry J; Thavaneswaran, Arane; Chandran, Vinod; Gladman, Dafna D

    2017-08-01

    The aims of this study were to describe the indications for, and features of, axial/peripheral joint magnetic resonance imaging (MRI) in psoriatic arthritis (PsA) and to examine the influence of MRI findings on clinical practice. All axial and peripheral (hand and/or foot) MRI scans on patients attending the Toronto PsA clinic l between 2003 and 2014 were included. Scan details were garnered from the radiologist's official report. A chart review was performed to determine if MRI findings contributed to a change of treatment. One hundred sixty-eight scans were performed on 125 patients (135 axial and 33 peripheral). The mean age was 50.5 (SD, 11.5) years, with 51.2% being female. Mean duration of PsA was 11.2 (SD, 10.9) years. Of the axial scans, the majority were performed on the whole spine (excluding the sacrum) (27.4%) or the sacroiliac joints and spine together (45.2%). The predominant indications were for suspected inflammatory (51.1%) or degenerative (24.4%) disease. Magnetic resonance imaging revealed inflammatory and/or structural change in 34.1% versus 54.8% with degenerative changes. In MRI axial inflammation (n = 25), the majority (48%) had sacroiliac joint involvement, whereas 28% had inflammation at 2 or more sites.Of the periphery, 60.6% of scans were on hands and 21.2% were on feet alone. The main indications were for suspected subclinical synovitis (78.8%). Inflammatory arthritis was the MRI diagnosis in 72.7%. Magnetic resonance imaging findings influenced treatment change (n = 32) in 56.3%, but were insufficient to effect treatment change without clinical findings (100%). Magnetic resonance imaging is useful in evaluating patients with active PsA, particularly when suspecting inflammation and radiographic findings are unhelpful. In some cases, it can be used as an adjunct to clinical examination in determining treatment change.

  14. Effect of pharmacist intervention on physician prescribing in patients with chronic schizophrenia: a descriptive pre/post study.

    PubMed

    Hashimoto, Yasuhiko; Tensho, Masami

    2016-04-26

    Although pharmacotherapy is one of the most important treatments for schizophrenia, the prominent levels of antipsychotic polypharmacy and high-dose regimens used in Japan are thought to be inconsistent with treatment regimens used in other countries. In this study, we evaluated the effect of pharmacist intervention on physician prescribing in patients with chronic schizophrenia. Participants comprised 52 inpatients at Sawa Hospital (Osaka, Japan), treated with at least one antipsychotic agent, who received pharmacist intervention for 1 year (2012). We compared the dose and the number of antipsychotics prescribed, and the rate of concurrent prescribing of anti-Parkinson, benzodiazepine and mood-stabilizer medication, pre- and post-pharmacist intervention. As an indicator of psychosis symptoms, the rate of seclusion room use was recorded. Additionally, we evaluated the impact of pharmacist intervention on medicine costs. Continuous variables were analyzed by Wilcoxon signed-rank sum tests, and categorical data were analyzed using Fisher's exact tests. Compared with pre-intervention, the dose (982.6 mg pre vs. 857.6 mg post; p < 0.01) and the number of antipsychotics (2.0 pre vs. 2.0 post; p < 0.05) at 1 year were significantly lower post-intervention. The seclusion room use rate was not significantly different but tended to be lower post-intervention than pre-intervention (p < 0.1). The cost (in USD) for all medicines (10.33 pre vs. 8.76 post; p < 0.05), antipsychotics (8.04 pre vs. 6.48 post; p < 0.05), and psychotropics (9.24 pre vs. 7.68 post; p < 0.01) were significantly lower post-intervention than pre-intervention. Pharmacist intervention has the potential to optimize medication prescribing and reduce medication costs in patients with chronic schizophrenia. It might be suggested that clinical practitioners as well as medical hospital administrators consider the pharmacists' ability to rationalize medication therapy in schizophrenia.

  15. A descriptive study of older adults with persistent pain: Use and perceived effectiveness of pain management strategies [ISRCTN11899548

    PubMed Central

    Kemp, Carol A; Ersek, Mary; Turner, Judith A

    2005-01-01

    Background Persistent pain is a common, often debilitating, problem in older adults; however, few studies have focused on the experiences of older adults in managing their pain. The objective of this study was to describe the use and perceived effectiveness of pain management strategies in a sample of older adults and to explore the associations of these variables with demographic and psychosocial characteristics. Methods Adults ≥ 65 years old and living in retirement facilities who reported persistent pain (N = 235, mean age = 82 years, 84% female, 94% white) completed measures of demographics, pain, depression, self-efficacy for managing pain, and a Pain Management Strategies Survey. Participants identified current and previous-year use of 42 pain management strategies and rated helpfulness of each on a 5-point scale. Results Acetaminophen, regular exercise, prayer, and heat and cold were the most frequently used pain management strategies (61%, 58%, 53%, and 48%, respectively). Strategies used by >25% of the sample that were rated moderately or more helpful (i.e., >2 on a 0 to 4 scale) were prayer [mean (SD) = 2.9 (0.9)], opioids [2.6 (0.8)], regular exercise [2.5 (1.0)], heat/cold [2.5 (1.0)], nonsteroidal anti-inflammatory drugs [2.4 (1.0)], and acetaminophen [2.3 (1.0)]. Young-old (65–74 years) study participants reported use of more strategies than did old-old (85+ years) participants (p = .03). Perceived helpfulness of strategy use was significantly associated with pain intensity (r = -.14, p < .0001), self-efficacy (r = .28, p < .0001), and depression (r = -.20, p = .003). Conclusion On average, older adults view the strategies they use for persistent pain as only moderately helpful. The associations between perceived helpfulness and self-efficacy and depression suggest avenues of pain management that are focused less on specific treatments and more on how persons with persistent pain think about their pain. PMID:16277666

  16. Surveillance for the safety and effectiveness of artemether-lumefantrine in patients with uncomplicated Plasmodium falciparum malaria in the USA: a descriptive analysis.

    PubMed

    Gray, Alyson M; Arguin, Paul M; Hamed, Kamal

    2015-09-17

    Data from clinical studies show that artemether-lumefantrine (AL) is effective and well tolerated in adults and children with uncomplicated Plasmodium falciparum malaria. However, data on effectiveness and safety of AL in patients in non-endemic settings are limited. A 5-year surveillance plan included all AL-treated adult and paediatric patients with confirmed or suspected P. falciparum malaria in the USA, as reported to the National Malaria Surveillance System at the Centers for Disease Control and Prevention. Descriptive analyses included demographics, baseline characteristics, clinical effectiveness, and safety. From May 2010 to April 2015, demographics and baseline characteristics were collected for 203 patients and safety data for 108 patients. Treatment effectiveness data at day 7 were collected for 117 patients and at day 28 for 98 patients. The majority of patients were male (58.6 %), Black (62.6 %), non-Hispanic (92.6 %), and likely malaria non-immune (80.8 %). The median age was 32 (range 1-88) years and the median body mass index was 25.5 (range 13.8-42.4) kg/m(2). All patients with effectiveness data had confirmed (n = 116) or suspected (n = 1) malaria. The overall cure rate for patients treated with AL was 91.5 % (95 % CI 84.8-95.8 %) at day 7 and 96.9 % (95 % CI 91.3-99.4 %) at day 28. Adverse events were reported in four (3.7 %) patients, and there were no new or unexpected safety signals. AL was effective and well tolerated in the treatment of likely non-immune patients with P. falciparum malaria.

  17. GROUNDWATER PROTECTION MANAGEMENT PROGRAM DESCRIPTION.

    SciTech Connect

    PAQUETTE,D.E.; BENNETT,D.B.; DORSCH,W.R.; GOODE,G.A.; LEE,R.J.; KLAUS,K.; HOWE,R.F.; GEIGER,K.

    2002-05-31

    THE DEPARTMENT OF ENERGY ORDER 5400.1, GENERAL ENVIRONMENTAL PROTECTION PROGRAM, REQUIRES THE DEVELOPMENT AND IMPLEMENTATION OF A GROUNDWATER PROTECTION PROGRAM. THE BNL GROUNDWATER PROTECTION MANAGEMENT PROGRAM DESCRIPTION PROVIDES AN OVERVIEW OF HOW THE LABORATORY ENSURES THAT PLANS FOR GROUNDWATER PROTECTION, MONITORING, AND RESTORATION ARE FULLY DEFINED, INTEGRATED, AND MANAGED IN A COST EFFECTIVE MANNER THAT IS CONSISTENT WITH FEDERAL, STATE, AND LOCAL REGULATIONS.

  18. One-electron reduction of 9, 10-anthraquinone, 1-amino-9, 10-anthraquinone and 1-hydroxy-9, 10-anthraquinone in aqueous-isopropanol-acetone mixed solvent: A pulse radiolysis study

    NASA Astrophysics Data System (ADS)

    Pal, H.; Mukherjee, T.; Mittal, J. P.

    1994-12-01

    The semiquinone radicals produced by one-electron reduction of 9, 10-anthraquinone, 1-amino-9, 10-anthraquinone and 1-hydroxy-9, 10-anthraquinone have been characterized in aqueous-organic mixed solvent comprising of 30.2 mol dm -3 water, 5 mol dm -3 isopropanol and 1 mol dm -3 acetone, using the pulse radiolysis technique. Spectroscopic characteristics, the kinetic parameters of formation and decay and one acid dissociation constants of the semiquinones and one-electron reduction potentials of the quinones have been estimated. The characteristics of the present semiquinone systems have been compared with those of other similar systems. The observed differences in characteristics of the semiquinones due to different substitutions have been analysed.

  19. The effect of sibutramine, a serotonin-norepinephrine reuptake inhibitor, on platelets and fibrin networks of male Sprague-Dawley rats: a descriptive study.

    PubMed

    van der Schoor, Ciska; Oberholzer, Hester Magdalena; Bester, Megan Jean; van Rooy, Mia-Jeanne

    2014-12-01

    Sibutramine is used in the treatment of obesity due to its ability to influence feelings of hunger and satiety by inhibiting the re-uptake of serotonin and noradrenalin in the central nervous system (CNS). Sibutramine use has been associated with numerous adverse events in particular cardiovascular complications possibly due to the formation of thrombi. This ultrastructural descriptive study investigated the effect of sibutramine on blood coagulation, specifically the effect on morphology of platelets and fibrin networks using scanning electron microscopy. Male Sprague-Dawley rats treated with either a recommended therapeutic dose [low dosage 1.32 mg/kg] or a toxicological higher dose [high dosage 13.2 mg/kg] of sibutramine for 28 days were used and compared to control animals. Blood samples were collected and plasma smears were prepared for platelet evaluation. Following the addition of thrombin to the plasma samples, the morphology of the fibrin clots was evaluated. Platelet evaluation by scanning electron microscopy revealed morphology typical of a prothrombotic state with a characteristic excessive platelet activation in both low-dose (LD) and high-dose (HD) rats. The fibrin clots of sibutramine-treated rats, LD and HD revealed fused thick fibers with thin fibers forming a net-like structure over the thick fibers which differ considerably from the organized structure of the control animals. It can be concluded that sibutramine alters the ultrastructure of platelets and fibrin networks creating a prothrombotic state.

  20. Reliability of semiology description.

    PubMed

    Heo, Jae-Hyeok; Kim, Dong Wook; Lee, Seo-Young; Cho, Jinwhan; Lee, Sang-Kun; Nam, Hyunwoo

    2008-01-01

    Seizure semiology is important for classifying patients' epilepsy. Physicians usually get most of the seizure information from observers though there have been few reports on the reliability of the observers' description. This study aims at determining the reliability of observers' description of the semiology. We included 92 patients who had their habitual seizures recorded during video-EEG monitoring. We compared the semiology described by the observers with that recorded on the videotape, and reviewed which characteristics of the observers affected the reliability of their reported data. The classification of seizures and the individual components of the semiology based only on the observer-description was somewhat discordant compared with the findings from the videotape (correct classification, 85%). The descriptions of some ictal behaviors such as oroalimentary automatism, tonic/dystonic limb posturing, and head versions were relatively accurate, but those of motionless staring and hand automatism were less accurate. The specified directions by the observers were relatively correct. The accuracy of the description was related to the educational level of the observers. Much of the information described by well-educated observers is reliable. However, every physician should keep in mind the limitations of this information and use this information cautiously.

  1. One-Electron Oxidation of Methionine-Containing Dipeptides of Reverse Sequence: Sulfur versus Sulfoxide Characterized by IRMPD Spectroscopy and Static and Dynamics DFT Simulations.

    PubMed

    Gregori, Barbara; Guidoni, Leonardo; Crestoni, Maria Elisa; de Oliveira, Pedro; Houée-Levin, Chantal; Scuderi, Debora

    2017-02-24

    Gas-phase structural modifications induced by the oxidation of methionine of the two peptides of reverse sequence, methionine-valine (Met-Val) and valine-methionine (Val-Met), have been studied by mass-selected IR multiple photon dissociation (IRMPD) spectroscopy in the 800-2000 cm(-1) fingerprint range at the Centre Laser Infrarouge d'Orsay free-electron laser facility. The oxidation has been achieved by (•)OH radicals generated by γ radiolysis. IRMPD spectra were interpreted by static and harmonic DFT calculations and Born-Oppenheimer molecular dynamics simulations, which are employed to take into account all anharmonic and finite-temperature effects. The diagnostic signature of the sulfoxide group in the final products of Met-Val and Val-Met oxidations, which is missing in the spectra of native peptides, has been recorded. Evidence has also been gathered that a mixture of R and S isomers of close energies is formed. An interconversion between different isomers has been unveiled in the case of the oxidized Met-Val dipeptide.

  2. Concerted One-Electron Two-Proton Transfer Processes in Models Inspired by the Tyr-His Couple of Photosystem II

    DOE PAGES

    Huynh, Mioy T.; Mora, S. Jimena; Villalba, Matias; ...

    2017-05-09

    Nature employs a TyrZ-His pair as a redox relay that couples proton transfer to the redox process between P680 and the water oxidizing catalyst in photosystem II. Artificial redox relays composed of different benzimidazole–phenol dyads (benzimidazole models His and phenol models Tyr) with substituents designed to simulate the hydrogen bond network surrounding the TyrZ-His pair have been prepared. Furthermore, when the benzimidazole substituents are strong proton acceptors such as primary or tertiary amines, theory predicts that a concerted two proton transfer process associated with the electrochemical oxidation of the phenol will take place. Furthermore, theory predicts a decrease in themore » redox potential of the phenol by ~300 mV and a small kinetic isotope effect (KIE). Indeed, electrochemical, spectroelectrochemical, and KIE experimental data are consistent with these predictions. Our results were obtained by using theory to guide the rational design of artificial systems and have implications for managing proton activity to optimize efficiency at energy conversion sites involving water oxidation and reduction.« less

  3. CRAC2 model description

    SciTech Connect

    Ritchie, L.T.; Alpert, D.J.; Burke, R.P.; Johnson, J.D.; Ostmeyer, R.M.; Aldrich, D.C.; Blond, R.M.

    1984-03-01

    The CRAC2 computer code is a revised version of CRAC (Calculation of Reactor Accident Consequences) which was developed for the Reactor Safety Study. This document provides an overview of the CRAC2 code and a description of each of the models used. Significant improvements incorporated into CRAC2 include an improved weather sequence sampling technique, a new evacuation model, and new output capabilities. In addition, refinements have been made to the atmospheric transport and deposition model. Details of the modeling differences between CRAC2 and CRAC are emphasized in the model descriptions.

  4. Spectrum of the open QCD flux tube and its effective string description I: 3d static potential in SU( N = 2 , 3)

    NASA Astrophysics Data System (ADS)

    Brandt, Bastian B.

    2017-07-01

    We perform a high precision measurement of the static q\\overline{q} potential in three-dimensional SU( N) gauge theory with N = 2 , 3 and compare the results to the potential obtained from the effective string theory. In particular, we show that the exponent of the leading order correction in 1 /R is 4, as predicted, and obtain accurate results for the continuum limits of the string tension and the non-universal boundary coefficient {\\overline{b}}_2 , including an extensive analysis of all types of systematic uncertainties. We find that the magnitude of {\\overline{b}}_2 decreases with increasing N, leading to the possibility of a vanishing {\\overline{b}}_2 in the large N limit. In the standard form of the effective string theory possible massive modes and the presence of a rigidity term are usually not considered, even though they might give a contribution to the energy levels. To investigate the effect of these terms, we perform a second analysis, including these contributions. We find that the associated expression for the potential also provides a good description of the data. The resulting continuum values for {\\overline{b}}_2 are about a factor of 2 smaller than in the standard analysis, due to contaminations from an additional 1 /R 4 term. However, {\\overline{b}}_2 shows a similar decrease in magnitude with increasing N. In the course of this extended analysis we also obtain continuum results for the masses appearing in the additional terms and we find that they are around twice as large as the square root of the string tension in the continuum and compatible between SU(2) and SU(3) gauge theory. In the follow up papers we will extend our investigations to the large N limit and excited states of the open flux tube.

  5. One-electron reduction of ferriporphyrins and reactions of ferric and ferrous porphyrins with a halothane-derived radical. [Gamma Radiation

    SciTech Connect

    Brault, D.; Neta, P.

    1982-08-19

    The reduction of ferrideuteroporphyrin by ..cap alpha..-hydroxyisopropyl radicals is investigated in acidic 2-propanol and acidic 2-propanol-water mixtures by means of steady-state and pulse radiolysis. The rate constant of the reaction is much higher (k approx. = 1.3 x 10/sup 9/ M/sup -1/s/sup -1/) than that reported for neutral solutions emphasizing the effect of the positive charge carried by the ferric porphyrin in acidic solutions (due to protonation of the alkoxide ligand). Competition kinetic experiments using p-nitroacetophenone as a referene solute show that ..cap alpha..-hydroxyisopropyl radicals are readily scavenged by halothane (CF/sub 3/CHClBr), leading to CF/sub 3/CHCl radicals. Pulse irradiation of ferriporphyrin solutions containing halothane allows investigation of the reaction of CF/sub 3/CHCl radicals with either ferric or ferrous prophyrins depending on the halothane concentration. No reaction of CF/sub 3/CHCl radicals with ferriporphyrin can be detected (k less than or equal to 10/sup 6/ M/sup -1/ s/sup -1/). On the other hand, a nearly diffusion-controlled reaction is observed between CF/sub 3/CHCl radicals and ferrous porphyrin leading to the sigma-bonded alkyl complex of the ferric porphyrin (PFe/sup III/CF/sub 3/CHCl, where CF/sub 3/CHCl stands for the alkyl anion). These results are discussed with regard to the reactivity of other alkyl radicals. The relevance to biological models of toxicity of halothane (a widely used anesthetic agent) is outlined.

  6. I've got 99 problems but a phone ain't one: Electronic and mobile health in low and middle income countries.

    PubMed

    Kumar, Pratap; Paton, Chris; Kirigia, Doris

    2016-10-01

    Mobile technology is very prevalent in Kenya-mobile phone penetration is at 88% and mobile data subscriptions form 99% of all internet subscriptions. While there is great potential for such ubiquitous technology to revolutionise access and quality of healthcare in low-resource settings, there have been few successes at scale. Implementations of electronic health (e-Health) and mobile health (m-Health) technologies in countries like Kenya are yet to tackle human resource constraints or the political, ethical and financial considerations of such technologies. We outline recent innovations that could improve access and quality while considering the costs of healthcare. One is an attempt to create a scalable clinical decision support system by engaging a global network of specialist doctors and reversing some of the damaging effects of medical brain drain. The other efficiently extracts digital information from paper-based records using low-cost and locally produced tools such as rubber stamps to improve adherence to clinical practice guidelines. By bringing down the costs of remote consultations and clinical audit, respectively, these projects offer the potential for clinics in resource-limited settings to deliver high-quality care. This paper makes a case for continued and increased investment in social enterprises that bridge academia, public and private sectors to deliver sustainable and scalable e-Health and m-Health solutions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  7. Effect of the barometric phase transition of a DMPA bilayer on the lipid/water interface. An atomistic description by molecular dynamics simulation.

    PubMed

    Casares, J J Giner; Camacho, L; Romero, M T Martín; Cascales, J J López

    2007-12-13

    Understanding the structure and dynamics of phospholipid bilayers is of fundamental relevance in biophysics, biochemistry, and chemical physics. Lipid Langmuir monolayers are used as a model of lipid bilayers, because they are much more easily studied experimentally, although some authors question the validity of this model. With the aim of throwing light on this debate, we used molecular dynamics simulations to obtain an atomistic description of a membrane of dimyristoylphosphatidic acid under different surface pressures. Our results show that at low surface pressure the interdigitation between opposite lipids (that is, back-to-back interactions) controls the system structure. In this setting and due to the absence of this effect in the Langmuir monolayers, the behavior between these two systems differs considerably. However, when the surface pressure increases the lipid interdigitation diminishes and so monolayer and bilayer behavior converges. In this work, four computer simulations were carried out, subjecting the phospholipids to lateral pressures ranging from 0.17 to 40 mN/m. The phospholipids were studied in their charged state because this approach is closer to the experimental situation. Special attention was paid to validating our simulation results by comparison with available experimental data, therebeing in general excellent agreement between experimental and simulation data. In addition, the properties of the lipid/solution interface associated with the lipid barometric phase transition were studied.

  8. Effect of the tensor part of Skyrme interaction on the description of elastic nucleon-nucleus scattering on the basis of the optical model

    SciTech Connect

    Kuprikov, V. I.; Pilipenko, V. V.

    2013-01-15

    A microscopic optical nucleon-nucleus potential constructed on the basis of calculating the mass operator for the single-particle Green's function with Skyrme nucleon-nucleon forces was used to study the effect of the tensor part of Skyrme forces on describing differential cross sections for elastic nucleon-nucleus scattering and the structure of nuclei within a self-consistent approach. It was shown that an increase in the tensor terms of nucleon-nucleon forces impaired the description of nucleon-nucleus scattering within the model being considered. The parameters of Skyrme forces were optimized on the basis of an analysis of cross sections for neutron-nucleus scattering, the properties of nuclear matter and the structure of nuclei being tested in doing this. This optimization led to nucleon-nucleon force versions where the tensor part was small or zero and which described satisfactorily the structure of nuclei and cross sections for elastic neutron and proton scattering on nuclei over a broad range of target mass numbers.

  9. One-electron oxidation of DNA by ionizing radiation: competition between base-to-base hole-transfer and hole-trapping.

    PubMed

    Sharma, Kiran K K; Tyagi, Rahul; Purkayastha, Shubhadeep; Bernhard, William A

    2010-06-10

    The distance of hole migration through DNA determines the degree to which radiation-induced lesions are clustered. It is the degree of clustering that confers to ionizing radiation its high toxicity. The migration distance is governed by a competition between hole transfer and irreversible trapping reactions. An important type of trapping is reactions that lead to the formation of deoxyribose radicals, which are precursors to free base release (fbr). Using HPLC, fbr was measured in X-irradiated films of d(CGCGCGCGCG)(2) and d(CGCGAATTCGCG)(2) as well as three genomic DNAs: M. luteus, calf thymus, and C. perfringens. The level of DNA hydration was varied from Gamma = 2.5 to 22 mol waters/mol nucleotide. The chemical yields of each base, G(base), were measured and used to calculate the modification factor, M(base). This factor compensates for differences in the GC/AT ratio, providing a measure of the degree to which a given base influences its own release. In the DNA oligomers, M(Gua) > M(Cyt), a result ascribed to the previously observed end effect in short oligomers. In the highly polymerized genomic DNA, we found that M(Cyt) > M(Gua) and that M(Thy) is consistently the smallest of the M factors. For these same DNA films, the yields of total DNA trapped radicals, G(tot)(fr), were measured using EPR spectroscopy. The yield of deoxyribose radicals was calculated using G(dRib)(fr) = approximately 0.11 x G(tot)(fr). Comparing G(dRib)(fr) with total fbr, we found that only about half of the fbr is accounted for by deoxyribose radical intermediates. We conclude that for a hole on cytosine, Cyt(*+), base-to-base hole transfer competes with irreversible trapping by the deoxyribose. In the case of a hole on thymine, Thy(*+), base-to-base hole transfer competes with irreversible trapping by methyl deprotonation. Close proximity of Gua protects the deoxyribose of Cyt but sensitizes the deoxyribose of Thy.

  10. SUBJECTIVE DESCRIPTION OF TRAINEES.

    ERIC Educational Resources Information Center

    PEARCE, FRANK C.

    THIS REPORT GIVES A SUBJECTIVE DESCRIPTION OF THE GENERAL POPULATION FROM WHICH TRAINEES FOR THE MODESTO MULTI-OCCUPATIONAL PROJECT WERE SELECTED. IT INCLUDES AN EXTENSIVE STUDY OF THE SOCIOLOGICAL BACKGROUND OF A GROUP OF WHITE MIGRANTS WHO MOVED FROM THE EASTERN UNITES STATES TO CALIFORNIA. THE AUTHOR ALSO INCLUDED REFERENCES TO THE CHANGING…

  11. Chapter 4: Variant descriptions

    Treesearch

    Duncan C. Lutes; Donald C. E. Robinson

    2003-01-01

    The Fire and Fuels Extension (FFE) to the Forest Vegetation Simulator (FVS) simulates fuel dynamics and potential fire behavior over time, in the context of stand development and management. This report documents differences between geographic variants of the FFE. It is a companion document to the FFE "Model Description" and "User's Guide."...

  12. Plot Description (PD)

    Treesearch

    Robert E. Keane

    2006-01-01

    The Plot Description (PD) form is used to describe general characteristics of the FIREMON macroplot to provide ecological context for data analyses. The PD data characterize the topographical setting, geographic reference point, general plant composition and cover, ground cover, fuels, and soils information. This method provides the general ecological data that can be...

  13. MOPITT Product Descriptions

    Atmospheric Science Data Center

    2017-04-03

    ... Product Descriptions " (PDF).   T (Thermal or TIR):       Uses the instrument's thermal infrared channels and is most ... team members to exploit it properly. Compared to earlier TIR-based MOPITT products, this product exhibits larger random errors and may ...

  14. Andrew integrated reservoir description

    SciTech Connect

    Todd, S.P.

    1996-12-31

    The Andrew field is an oil and gas accumulation in Palaeocene deep marine sands in the Central North Sea. It is currently being developed with mainly horizontal oil producers. Because of the field`s relatively small reserves (mean 118 mmbbls), the performance of each of the 10 or so horizontal wells is highly important. Reservoir description work at sanction time concentrated on supporting the case that the field could be developed commercially with the minimum number of wells. The present Integrated Reservoir Description (IRD) is focussed on delivering the next level of detail that will impact the understanding of the local reservoir architecture and dynamic performance of each well. Highlights of Andrew IRD Include: (1) Use of a Reservoir Uncertainty Statement (RUS) developed at sanction time to focus the descriptive effort of both asset, support and contract petrotechnical staff, (2) High resolution biostratigraphic correlation to support confident zonation of the reservoir, (3) Detailed sedimentological analysis of the core including the use of dipmeter to interpret channel/sheet architecture to provide new insights into reservoir heterogeneity; (4) Integrated petrographical and petrophysical investigation of the controls on Sw-Height and relative permeability of water; (5) Fluids description using oil geochemistry and Residual Salt Analysis Sr isotope studies. Andrew IRD has highlighted several important risks to well performance, including the influence of more heterolithic intervals on gas breakthrough and the controls on water coning exerted by suppressed water relative permeability in the transition zone.

  15. Andrew integrated reservoir description

    SciTech Connect

    Todd, S.P.

    1996-01-01

    The Andrew field is an oil and gas accumulation in Palaeocene deep marine sands in the Central North Sea. It is currently being developed with mainly horizontal oil producers. Because of the field's relatively small reserves (mean 118 mmbbls), the performance of each of the 10 or so horizontal wells is highly important. Reservoir description work at sanction time concentrated on supporting the case that the field could be developed commercially with the minimum number of wells. The present Integrated Reservoir Description (IRD) is focussed on delivering the next level of detail that will impact the understanding of the local reservoir architecture and dynamic performance of each well. Highlights of Andrew IRD Include: (1) Use of a Reservoir Uncertainty Statement (RUS) developed at sanction time to focus the descriptive effort of both asset, support and contract petrotechnical staff, (2) High resolution biostratigraphic correlation to support confident zonation of the reservoir, (3) Detailed sedimentological analysis of the core including the use of dipmeter to interpret channel/sheet architecture to provide new insights into reservoir heterogeneity; (4) Integrated petrographical and petrophysical investigation of the controls on Sw-Height and relative permeability of water; (5) Fluids description using oil geochemistry and Residual Salt Analysis Sr isotope studies. Andrew IRD has highlighted several important risks to well performance, including the influence of more heterolithic intervals on gas breakthrough and the controls on water coning exerted by suppressed water relative permeability in the transition zone.

  16. Effect of temperature and salinity on egg hatching and description of the life cycle of Lernanthropus latis (Copepoda: Lernanthropidae) infecting barramundi, Lates calcarifer.

    PubMed

    Brazenor, Alexander K; Hutson, Kate S

    2013-10-01

    The parasite Lernanthropus latis (Copepoda: Lernanthropidae) is a major threat to the sustained mariculture of barramundi, Lates calcarifer (Perciformes: Latidae). We investigated the effect of water temperature and salinity on egg hatching success of L. latis and describe the life cycle for the first time. Wild and sea-caged L. calcarifer examined in tropical north Australia exhibited similar parasite prevalence (range: 80-100%) and mean parasite intensity (range: 3-6), whereas land-based maricultured fish were not infected. Hatching success and time to first and last hatch was determined for a range of water temperature (22, 30, 32 and 34°C) and salinity (0, 11, 22, 35 and 40‰) combinations representing current and predicted climate conditions. There was a significant interaction between water temperature and salinity on the hatching success of L. latis nauplii. Eggs hatched in all temperature treatments, with the greatest hatching success at 30°C and 32°C (98 and 92% success, respectively) in 35‰. Hatching did not occur at 0‰ and was severely reduced at 11‰ (1.6% success). Hatching began within 6h at all water temperatures with >95% of eggs hatched within 30h at 30, 32 and 34°C and within 60h at 22°C. Adult parasites differed from the original description by the presence of the parabasal flagellum, small setae on the legs and caudal rami and minor incongruences regarding morphological measurements. The life cycle of L. latis includes three free living stages and five parasitic stages. Although L. latis exhibits broad environmental tolerance, freshwater can be used as an effective management strategy to break the life cycle in aquaculture.

  17. LIGKA: A linear gyrokinetic code for the description of background kinetic and fast particle effects on the MHD stability in tokamaks

    SciTech Connect

    Lauber, Ph. Guenter, S.; Koenies, A.; Pinches, S.D.

    2007-09-10

    In a plasma with a population of super-thermal particles generated by heating or fusion processes, kinetic effects can lead to the additional destabilisation of MHD modes or even to additional energetic particle modes. In order to describe these modes, a new linear gyrokinetic MHD code has been developed and tested, LIGKA (linear gyrokinetic shear Alfven physics) [Ph. Lauber, Linear gyrokinetic description of fast particle effects on the MHD stability in tokamaks, Ph.D. Thesis, TU Muenchen, 2003; Ph. Lauber, S. Guenter, S.D. Pinches, Phys. Plasmas 12 (2005) 122501], based on a gyrokinetic model [H. Qin, Gyrokinetic theory and computational methods for electromagnetic perturbations in tokamaks, Ph.D. Thesis, Princeton University, 1998]. A finite Larmor radius expansion together with the construction of some fluid moments and specification to the shear Alfven regime results in a self-consistent, electromagnetic, non-perturbative model, that allows not only for growing or damped eigenvalues but also for a change in mode-structure of the magnetic perturbation due to the energetic particles and background kinetic effects. Compared to previous implementations [H. Qin, mentioned above], this model is coded in a more general and comprehensive way. LIGKA uses a Fourier decomposition in the poloidal coordinate and a finite element discretisation in the radial direction. Both analytical and numerical equilibria can be treated. Integration over the unperturbed particle orbits is performed with the drift-kinetic HAGIS code [S.D. Pinches, Ph.D. Thesis, The University of Nottingham, 1996; S.D. Pinches et al., CPC 111 (1998) 131] which accurately describes the particles' trajectories. This allows finite-banana-width effects to be implemented in a rigorous way since the linear formulation of the model allows the exchange of the unperturbed orbit integration and the discretisation of the perturbed potentials in the radial direction. Successful benchmarks for toroidal Alfven

  18. Effect of breeding season on in vivo oocyte recovery and embryo production in non-descriptive Indian river buffaloes (Bubalus bubalis).

    PubMed

    Manjunatha, B M; Ravindra, J P; Gupta, P S P; Devaraj, M; Nandi, S

    2009-04-01

    The present study was carried out to examine the effect of season on in vivo oocyte recovery and embryo production in non-descriptive, Indian river buffaloes (Bubalus bubalis). Ovum pick up (OPU) was conducted twice a week for 8 weeks during peak (October-March) and low (April-September) breeding season in live buffaloes (n=6). OPU was performed using ultrasound equipment with a 5MHz transvaginal transducer, a single lumen 18-gauge, 55-cm long needle and a constant vacuum pressure of 110mmHg. The number and size of follicles was determined before puncture. The recovered oocytes were graded and only grade A and grade B oocytes were used for in vitro production (IVP) of embryos. The mean number of follicles observed per animal per session did not differed (P<0.05) between animals or between puncture sessions in both low and peak breeding seasons. Higher (P<0.05) number of follicles were observed (4.8+/-0.2 versus 3.1+/-0.3) and punctured (4.0+/-0.2 versus 2.4+/-0.2) during peak breeding season when compared to low breeding season. Oocytes recovered (1.6+/-0.1 versus 1.0+/-0.3) per animal per session were higher (P<0.05) in peak breeding season than low breeding season. During the peak breeding season, the blastocyst yield per animal per session (0.3+/-0.4 versus 0.18+/-0.4) was higher (P<0.05) than the low breeding season. However, season did not significantly affect the percentage of oocytes suitable for IVP (grade A+B) and blastocyst production rate. In conclusion, the efficiency of OPU combined with IVP was higher during the peak breeding season than the low breeding season in buffaloes.

  19. RETRIEVAL EQUIPMENT DESCRIPTIONS

    SciTech Connect

    J. Steinhoff

    1997-08-25

    The objective and the scope of this document are to list and briefly describe the major mobile equipment necessary for waste package (WP) retrieval from the proposed subsurface nuclear waste repository at Yucca Mountain. Primary performance characteristics and some specialized design features of the equipment are explained and summarized in the individual subsections of this document. There are no quality assurance requirements or QA controls in this document. Retrieval under normal conditions is accomplished with the same fleet of equipment as is used for emplacement. Descriptions of equipment used for retrieval under normal conditions is found in Emplacement Equipment Descriptions, DI: BCAF00000-01717-5705-00002 (a document in progress). Equipment used for retrieval under abnormal conditions is addressed in this document and consists of the following: (1) Inclined Plane Hauler; (2) Bottom Lift Transporter; (3) Load Haul Dump (LHD) Loader; (4) Heavy Duty Forklift for Emplacement Drifts; (5) Covered Shuttle Car; (6) Multipurpose Vehicle; and (7) Scaler.

  20. Reasoning about scene descriptions

    SciTech Connect

    DiManzo, M.; Adorni, G.; Giunchiglia, F.

    1986-07-01

    When a scene is described by means of natural language sentences, many details are usually omitted, because they are not in the focus of the conversation. Moreover, natural language is not the best tool to define precisely positions and spatial relationships. The process of interpreting ambiguous statements and inferring missing details involves many types of knowledge, from linguistics to physics. This paper is mainly concerned with the problem of modeling the process of understanding descriptions of static scenes. The specific topics covered by this work are the analysis of the meaning of spatial prepositions, the problem of the reference system and dimensionality, the activation of expectations about unmentioned objects, the role of default knowledge about object positions and its integration with contextual information sources, and the problem of space representation. The issue of understanding dynamic scenes descriptions is briefly approached in the last section.

  1. How Do DFT-DCP, DFT-NL, and DFT-D3 Compare for the Description of London-Dispersion Effects in Conformers and General Thermochemistry?

    PubMed

    Goerigk, Lars

    2014-03-11

    The dispersion-core-potential corrected B3LYP-DCP method (Torres and DiLabio J. Phys. Chem. Lett. 2012, 3, 1738) is for the first time thoroughly assessed and compared with the B3LYP-NL (Hujo and Grimme J. Chem. Theory Comput. 2011, 7, 3866) and B3LYP-D3 (Grimme et al. J. Comput. Chem. 2011, 32, 1456) methods for a broad range of chemical problems that particularly shed light on intramolecular London-dispersion effects in conformers and general thermochemistry. The analysis is based on a compilation of 473 reference cases, the majority of which are taken from the GMTKN30 database (Goerigk and Grimme J. Chem. Theory Comput. 2010, 6, 107; 2011, 7, 291). The results confirm previous findings that B3LYP-DCP indeed predicts very good binding energies for noncovalently bound complexes, particularly with small basis sets. However, problems are identified for the description of intramolecular effects in some conformers and chemical reactions, for which B3LYP-DCP sometimes gives results similar or worse than uncorrected B3LYP. Surprisingly large errors for total atomization energies reveal an unwanted influence of the DCPs on the short-range electronic structure of the investigated systems. However, a recently modified carbon potential for B3LYP-DCP (DiLabio et al. Theor. Chem. Acc. 2013, 132, 1389) was additionally tested that seems to solve most of those problems and provides improved results. An overall comparison between all tested methods shows that B3LYP-NL is the most robust and accurate approach, closely followed by B3LYP-D3. This is also true when small basis sets of double-ζ quality are applied for which those methods have not been parametrized. However, binding energies of noncovalently bound complexes can be more strongly influenced by basis-set superposition-error effects than for B3LYP-DCP. Finally, it is noted that the DFT-D3 and DFT-NL schemes are readily applicable to a large range of chemical elements and they are therefore particularly recommended for

  2. A descriptive study of the reported effects of state-mandated testing on the instructional practices and beliefs of middle school science teachers

    NASA Astrophysics Data System (ADS)

    Font-Rivera, Miriam Josefa

    The purpose of this study was to investigate the effects of state-level testing on the instructional practices and beliefs of middle school science teachers. The study addressed four questions: (a) What are the beliefs of middle school science teachers regarding the pressure to improve their students' test scores? (b) What are the beliefs of middle school science teachers about how standardized tests influence their class time? (c) What are the attitudes of middle school science teachers toward state testing? and (d) What commonalities emerge from teachers' responses about the state tests? The sample was composed of 86 middle school science teachers from states that have state mandated testing programs in the area of science. Descriptive statistics and an inductive analysis were performed to answer the research questions. Teachers reported that they and their students were under a great amount of pressure to increase test scores from central office administrators and from the school principal. Teachers reported spending considerable time on certain test preparation activities throughout the school year. Teachers reported that the three strongest influences in instructional planning were reviewing the content and skills covered on the state tests prior to the test administration, having to prepare students for state tests, and adjusting the curriculum sequence based on the content tested by the state tests. Multiple-choice items were reported to be the most often used assessment strategy. Teachers reported that state-mandated tests were not very helpful because the test results presented an inaccurate picture of student learning. The categories formed from the teachers' written comments reflected the findings of the survey questions. Comments concentrated on the negative effects of the tests in the areas of pressure, overemphasis on the test, accountability, reduction of instructional time due to test preparation, and negative uses of state-mandated tests

  3. Management control system description

    SciTech Connect

    Bence, P. J.

    1990-10-01

    This Management Control System (MCS) description describes the processes used to manage the cost and schedule of work performed by Westinghouse Hanford Company (Westinghouse Hanford) for the US Department of Energy, Richland Operations Office (DOE-RL), Richland, Washington. Westinghouse Hanford will maintain and use formal cost and schedule management control systems, as presented in this document, in performing work for the DOE-RL. This MCS description is a controlled document and will be modified or updated as required. This document must be approved by the DOE-RL; thereafter, any significant change will require DOE-RL concurrence. Westinghouse Hanford is the DOE-RL operations and engineering contractor at the Hanford Site. Activities associated with this contract (DE-AC06-87RL10930) include operating existing plant facilities, managing defined projects and programs, and planning future enhancements. This document is designed to comply with Section I-13 of the contract by providing a description of Westinghouse Hanford's cost and schedule control systems used in managing the above activities. 5 refs., 22 figs., 1 tab.

  4. Descriptive analyses of caregiver reprimands.

    PubMed

    Sloman, Kimberly N; Vollmer, Timothy R; Cotnoir, Nicole M; Borrero, Carrie S W; Borrero, John C; Samaha, Andrew L; St Peter, Claire C

    2005-01-01

    We conducted descriptive observations of 5 individuals with developmental disabilities and severe problem behavior while they interacted with their caregivers in either simulated environments (an inpatient hospital facility) or in their homes. The focus of the study was on caregiver reprimands and child problem behavior. Thus, we compared the frequency of problem behavior that immediately preceded a caregiver reprimand to that immediately following a caregiver reprimand, and the results showed that the frequency of problem behavior decreased following a reprimand. It is possible that caregiver reprimands are negatively reinforced by the momentary attenuation of problem behavior, and the implications for long- and short-term effects on caregiver behavior are discussed.

  5. MCO Monitoring activity description

    SciTech Connect

    SEXTON, R.A.

    1998-11-09

    Spent Nuclear Fuel remaining from Hanford's N-Reactor operations in the 1970s has been stored under water in the K-Reactor Basins. This fuel will be repackaged, dried and stored in a new facility in the 200E Area. The safety basis for this process of retrieval, drying, and interim storage of the spent fuel has been established. The monitoring of MCOS in dry storage is a currently identified issue in the SNF Project. This plan outlines the key elements of the proposed monitoring activity. Other fuel stored in the K-Reactor Basins, including SPR fuel, will have other monitoring considerations and is not addressed by this activity description.

  6. The Genre of Technical Description.

    ERIC Educational Resources Information Center

    Jordan, Michael P.

    1986-01-01

    Summarizes recent research into systems of lexical and grammatical cohesion in technical description. Discusses various methods by which technical writers "re-enter" the topic of description back into the text in successive sentences. (HTH)

  7. A prospective, longitudinal, descriptive study of the effect of a customized wheelchair cushion on clinical variables, satisfaction, and functionality among patients with spinal cord injury.

    PubMed

    Vilchis-Aranguren, Rodrigo; Gayol-Mérida, Diana; Quinzaños-Fresnedo, Jimena; Pérez-Zavala, Ramiro; Galíndez-Novoa, Carmen

    2015-02-01

    The Instituto Nacional de Rehabilitación (Rehabilitation National Institute) (INR) developed a prototype wheelchair cushion (INR cushion) designed to adjust to the anthropometry of the user's ischiogluteal area and prevent pressure ulcer formation while maintaining or promoting functionality. A prospective, longitudinal, descriptive study was conducted from February 2010 to February 2011 to evaluate the effect of using the INR cushion on clinical variables, functionality, and user satisfaction. Sixteen patients were recruited (9 male, 7 female, average age 31.8 [range 22-47] years, average body mass index 25 [range 22-34], average time in a wheelchair 10.1 [range 3-26] years) who met the study protocol inclusion criteria of being pressure ulcer-free for at least 6 months and capable of propulsion and transfer without assistance, chronic spinal cord injury (>2 years), and without chronic-degenerative diseases or cognitive problems. Each participant received the cushion for a 2-month evaluation. Eight clinical variables were assessed: trunk control, posture, spasticity, transfer capacity, comfort, skin reaction, propulsion capacity, and pressure release capacity. The clinical assessment was performed using validated scales and instruments: Modified Ashworth Scale (MAS), Functional Independence Measure™ (FIM), Norton Scale, and assessment of skin reaction. Interface pressures were measured using force sensing array, and participants completed a structured interview to assess user expectation, perceived functionality, perceived quality, and likelihood of recommending the device. Two patients withdrew due to appointment conflicts; of the remaining 14, significant differences between the user's experience with other products and the INR were found with regard to pressure redistribution (P = 0.012); all participants but 1 graded the INR as good in all interview categories. No participants developed a pressure ulcer during the study. The customized cushion was

  8. Three Approaches to Descriptive Research.

    ERIC Educational Resources Information Center

    Svensson, Lennart

    This report compares three approaches to descriptive research, focusing on the kinds of descriptions developed and on the methods used to develop the descriptions. The main emphasis in all three approaches is on verbal data. In these approaches the importance of interpretation and its intuitive nature are emphasized. The three approaches, however,…

  9. Effects of packaging materials on the aroma stability of Thai 'tom yam' seasoning powder as determined by descriptive sensory analysis and gas chromatography-mass spectrometry.

    PubMed

    Leelaphiwat, Pattarin; Harte, Janice B; Auras, Rafael A; Ong, Peter Kc; Chonhenchob, Vanee

    2017-04-01

    Changes in the aroma characteristics of Thai 'tom yam' seasoning powder, containing lemongrass, galangal and kaffir lime leaf, as affected by different packaging materials were assessed using quantitative descriptive analysis (QDA) and gas chromatography-mass spectrometry (GC-MS). The descriptive aroma attributes for lemongrass, galangal and kaffir lime leaf powders were developed by the QDA panel. The mixed herb and spice seasoning powder was kept in glass jars closed with different packaging materials (Nylon 6, polyethylene terephthalate (PET) and polylactic acid (PLA)) stored at 38 °C (accelerated storage condition), and evaluated by the trained QDA panel during storage for 49 days. The descriptive words for Thai 'tom yam' seasoning powder developed by the trained panelists were lemongrass, vinegary and leafy for lemongrass, galangal and kaffir lime leaf dried powder, respectively. The aroma intensities significantly (P ≤ 0.05) decreased with increased storage time. However, the intensity scores for aroma attributes were not significantly (P > 0.05) different among the packaging materials studied. The major components in Thai 'tom yam' seasoning powder, quantified by GC-MS, were estragole, bicyclo[3.1.1]heptane, β-bisabolene, benzoic acid and 2-ethylhexyl salicylate. The concentrations of major aroma compounds significantly (P ≤ 0.05) decreased with storage time. Aroma stability of Thai 'tom yam' powder can be determined by descriptive sensory evaluation and GC-MS analysis. Nylon, PET and PLA exhibited similar aroma barrier properties against key aroma compounds in Thai 'tom yam'. This information can be used for prediction of aroma loss through packaging materials during storage of Thai 'tom yam'. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  10. One-Electron Oxidation of [M(P(t) Bu3 )2 ] (M=Pd, Pt): Isolation of Monomeric [Pd(P(t) Bu3 )2 ](+) and Redox-Promoted C-H Bond Cyclometalation.

    PubMed

    Troadec, Thibault; Tan, Sze-Yin; Wedge, Christopher J; Rourke, Jonathan P; Unwin, Patrick R; Chaplin, Adrian B

    2016-03-07

    Oxidation of zero-valent phosphine complexes [M(P(t) Bu3 )2 ] (M=Pd, Pt) has been investigated in 1,2-difluorobenzene solution using cyclic voltammetry and subsequently using the ferrocenium cation as a chemical redox agent. In the case of palladium, a mononuclear paramagnetic Pd(I) derivative was readily isolated from solution and fully characterized (EPR, X-ray crystallography). While in situ electrochemical measurements are consistent with initial one-electron oxidation, the heavier congener undergoes C-H bond cyclometalation and ultimately affords the 14 valence-electron Pt(II) complex [Pt(κ(2) PC -P(t) Bu2 CMe2 CH2 )(P(t) Bu3 )](+) with concomitant formation of [Pt(P(t) Bu3 )2 H](+) . © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  11. Description of a Heart Team approach to coronary revascularization and its beneficial long-term effect on clinical events after PCI.

    PubMed

    Bonzel, Tassilo; Schächinger, Volker; Dörge, Hilmar

    2016-05-01

    We present a first description of a Heart Team (HT)-guided approach to coronary revascularization and its long-term effect on clinical events after percutaneous coronary intervention (PCI). The HT approach is a structured process to decide for coronary bypass grafting (CABG), PCI or conservative therapy in ad hoc situations as well as in HT conferences. As a hypothesis, during the long-term course after a PCI performed according to HT rules, a low number of late revascularizations, especially CABGs, are expected (F-PCI study). In this monocentric study, the HT approach to an all-comer population was first analyzed and described in general with the help of a database. Next the use of a HT approach was described for a more homogeneous subgroup with newly detected CAD (1.CAD). Those patients in whom the HT decision was PCI (which was a 1.PCI) were then studied with the help of questionnaires for clinical events during a very long-term follow-up. Events were CABG, PCI, diagnostic catheterization (DCath) and death. A significant number of patients were presented to HT conferences: 22 % out of all 11,174 catheterizations, 24 % out of all 7867 CAD cases and 35 % out of 3408 1.CAD cases. Most of these patients had multi-vessel disease (MVD). Conference decisions were isolated CABG in 46-66 %, PCI in 10-14 %, valvular surgery in 9-16 %, HTx in 10-21 % (Endstage heart failure candidates for surgery) and conservative therapy (Medical or no therapy, additional diagnostic procedures or no adherence to recommended therapy) in 2-3 %. However, most PCIs, ad hoc and elective, were performed under Heart Team rules, but without conference. During follow-up of 1.PCI patients (Kaplan-Meier analysis), CABG occurred in only 15 % of patients, PCI in 37 % and DCath in 65 %; mortality of any course was 51 %. Mortalities were similar in one-vessel disease and in a population of the same year, matched for age and sex (p < 0.057), but mortality was higher in 1.PCI patients with

  12. Tight-binding description of high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Richert, Brent A.; Allen, Roland E.

    1989-02-01

    A single tight-binding model, with fully transferable parameters, provides a good description of the electronic structures of all currently-known high-temperature superconductors, including the copper oxides La2-xSrxCuO4, YBa2Cu3O7, Bi2CaSr2Cu2O8, Tl2Ba2CuO6, Tl2CaBa2Cu2O8, and Tl2Ca2Ba2Cu3O10 and the bismuth oxide Ba1-xKxBiO3 (within the one-electron approximation). The energy bands, local densities of states, and atomic valences have been calculated for each material.

  13. The mechanism of oxidative halophenol dehalogenation by Amphitrite ornata dehaloperoxidase is initiated by H2O2 binding and involves two consecutive one-electron steps: role of ferryl intermediates.

    PubMed

    Osborne, Robert L; Coggins, Michael K; Raner, Gregory M; Walla, Mike; Dawson, John H

    2009-05-26

    The enzymatic globin, dehaloperoxidase (DHP), from the terebellid polychaete Amphitrite ornata is designed to catalyze the oxidative dehalogenation of halophenol substrates. In this study, the ability of DHP to catalyze this reaction by a mechanism involving two consecutive one-electron steps via the normal order of addition of the oxidant cosubstrate (H(2)O(2)) before organic substrate [2,4,6-trichlorophenol (TCP)] is demonstrated. Specifically, 1 equiv of H(2)O(2) will fully convert 1 equiv of TCP to 2,6-dichloro-1,4-benzoquinone, implicating the role of multiple ferryl [Fe(IV)O] species. A significant amount of heterolytic cleavage of the O-O bond of cumene hydroperoxide, consistent with transient formation of a Compound I [Fe(IV)O/porphyrin pi-cation radical] species, is observed upon its reaction with ferric DHP. In addition, a more stable high-valent Fe(IV)O-containing DHP intermediate [Compound II (Cpd II) or Compound ES] is characterized by UV-visible absorption and magnetic circular dichroism spectroscopy. Spectral similarities are seen between this intermediate and horse heart myoglobin Cpd II. It is also shown in single-turnover experiments that the DHP Fe(IV)O intermediate is an active oxidant in halophenol oxidative dehalogenation. Furthermore, reaction of DHP with 4-chlorophenol leads to a dimeric product. The results presented herein are consistent with a normal peroxidase order of addition of the oxidant cosubstrate (H(2)O(2)) followed by organic substrate (TCP) and indicate that the enzymatic mechanism of DHP-catalyzed oxidative halophenol dehalogenation involves two consecutive one-electron steps with a dissociable radical intermediate.

  14. Task Description Language

    NASA Technical Reports Server (NTRS)

    Simmons, Reid; Apfelbaum, David

    2005-01-01

    Task Description Language (TDL) is an extension of the C++ programming language that enables programmers to quickly and easily write complex, concurrent computer programs for controlling real-time autonomous systems, including robots and spacecraft. TDL is based on earlier work (circa 1984 through 1989) on the Task Control Architecture (TCA). TDL provides syntactic support for hierarchical task-level control functions, including task decomposition, synchronization, execution monitoring, and exception handling. A Java-language-based compiler transforms TDL programs into pure C++ code that includes calls to a platform-independent task-control-management (TCM) library. TDL has been used to control and coordinate multiple heterogeneous robots in projects sponsored by NASA and the Defense Advanced Research Projects Agency (DARPA). It has also been used in Brazil to control an autonomous airship and in Canada to control a robotic manipulator.

  15. Description of Jet Breakup

    NASA Technical Reports Server (NTRS)

    Papageorgiou, Demetrios T.

    1996-01-01

    In this article we review recent results on the breakup of cylindrical jets of a Newtonian fluid. Capillary forces provide the main driving mechanism and our interest is in the description of the flow as the jet pinches to form drops. The approach is to describe such topological singularities by constructing local (in time and space) similarity solutions from the governing equations. This is described for breakup according to the Euler, Stokes or Navier-Stokes equations. It is found that slender jet theories can be applied when viscosity is present, but for inviscid jets the local shape of the jet at breakup is most likely of a non-slender geometry. Systems of one-dimensional models of the governing equations are solved numerically in order to illustrate these differences.

  16. Symmetrical gait descriptions

    NASA Astrophysics Data System (ADS)

    Dunajewski, Adam; Dusza, Jacek J.; Rosado Muñoz, Alfredo

    2014-11-01

    The article presents a proposal for the description of human gait as a periodic and symmetric process. Firstly, the data for researches was obtained in the Laboratory of Group SATI in the School of Engineering of University of Valencia. Then, the periodical model - Mean Double Step (MDS) was made. Finally, on the basis of MDS, the symmetrical models - Left Mean Double Step and Right Mean Double Step (LMDS and RMDS) could be created. The method of various functional extensions was used. Symmetrical gait models can be used to calculate the coefficients of asymmetry at any time or phase of the gait. In this way it is possible to create asymmetry, function which better describes human gait dysfunction. The paper also describes an algorithm for calculating symmetric models, and shows exemplary results based on the experimental data.

  17. Lagrangian description of warm plasmas

    NASA Technical Reports Server (NTRS)

    Kim, H.

    1970-01-01

    Efforts are described to extend the averaged Lagrangian method of describing small signal wave propagation and nonlinear wave interaction, developed by earlier workers for cold plasmas, to the more general conditions of warm collisionless plasmas, and to demonstrate particularly the effectiveness of the method in analyzing wave-wave interactions. The theory is developed for both the microscopic description and the hydrodynamic approximation to plasma behavior. First, a microscopic Lagrangian is formulated rigorously, and expanded in terms of perturbations about equilibrium. Two methods are then described for deriving a hydrodynamic Lagrangian. In the first of these, the Lagrangian is obtained by velocity integration of the exact microscopic Lagrangian. In the second, the expanded hydrodynamic Lagrangian is obtained directly from the expanded microscopic Lagrangian. As applications of the microscopic Lagrangian, the small-signal dispersion relations and the coupled mode equations are derived for all possible waves in a warm infinite, weakly inhomogeneous magnetoplasma, and their interactions are examined.

  18. Quark description of nuclear matter

    SciTech Connect

    Berges, Jurgen

    2001-07-01

    We discuss the role of an adjoint chiral condensate for color superconducting quark matter. Its presence leads to color-flavor locking in two-flavor quark matter. Color is broken completely as well as chiral symmetry in the two-flavor theory with coexisting adjoint quark-antiquark and antitriplet quark-quark condensates. The qualitative properties of this phase match the properties of ordinary nuclear matter without strange baryons. This complements earlier proposals by Schaefer and Wilczek for a quark description of hadronic phases. We show for a class of models with effective four-fermion interactions that adjoint chiral and diquark condensates do not compete, in the sense that simultaneous condensation occurs for sufficiently strong interactions in the adjoint chiral channel.

  19. [Molluscum contagiosum: descriptive study].

    PubMed

    Monteagudo, B; Cabanillas, M; Acevedo, A; de Las Heras, C; Pérez-Pérez, L; Suárez-Amor, O; Ginarte, M

    2010-02-01

    Molluscum contagiosum is a cutaneous viral infection that often requires assistance. The aim of our study is to review the cases admitted in our clinic, evaluate the epidemiological features and the treatment prescribed. We conducted a descriptive survey of the patients diagnosed of molluscum contagiosum in our clinic (Complexo Hospitalario Arquitecto Marcide-Novoa Santos, Ferrol, Spain) between June 16th 2008 and January 15th 2009. The following dates were recorded in all cases: age, sex, personal history of atopy, swimming pool attendance, number of lesions and treatment prescribed. 140 cases of molluscum contagiosum were included in the study. Average age was 10.7 years. 51.43% of patients had a personal history of atopy and 72.1% used to attendance swimming-pool. Average number of lesions was 13.3, with a higher number of them in males, atopic and swimming-pool attendants. Curettage was the treatment performed in 86.4% of cases. Atopic dermatitis and swimming-pool attendance were associated in our study with a higher frequency and number of molluscum contagiosum. Although different therapeutic options must be evaluated depending on the patient and clinical skills, curettage is the most frequent treatment performed by dermatologists.

  20. CGL description revisited

    SciTech Connect

    Hunana, P.; Zank, G. P.; Webb, G. M.; Adhikari, L.; Goldstein, M. L.

    2016-03-25

    Solar wind observational studies have emphasized that the solar wind plasma data is bounded by the mirror and firehose instabilities, and it is often believed that these instabilities are of a purely kinetic nature. The simplest fluid model that generalizes magnetohydrodynamics with anisotropic temperatures is the Chew-Goldberger-Low model (CGL). Here we briefly revisit the CGL description and discuss its (otherwise well-documented) linear firehose and mirror instability thresholds; namely that the firehose instability threshold is identical to the one found from linear kinetic theory and that the mirror threshold contains a factor of 6 error. We consider a simple higher-order fluid model with time dependent heat flux equations and show that the mirror instability threshold is correctly reproduced. We also present fully nonlinear three-dimensional simulations of freely decaying turbulence for the Hall-CGL model with isothermal electrons. The spatial resolution of these simulations is 512{sup 3} and the formation of a spectral break in magnetic and velocity field spectra around the proton inertial length is found.

  1. Formal description of disease courses.

    PubMed

    van der Maas, A A; ter Hofstede, A H

    2000-01-01

    Patient case analysis is an elementary and crucial process clinicians are confronted with daily. The importance and complexity is reflected in the need to discuss individual patient cases in clinicopathological conferences and the documentation of more than 70,000 patient cases in MEDLINE. This paper introduces DCGL, a technique to model disease course descriptions as present in medical literature. DCGL enables advanced computerised matching of generic disease course descriptions with individual patient case descriptions, a basic function in computerised patient case analysis.

  2. Aesthetic Description and Realism in Art Education.

    ERIC Educational Resources Information Center

    Brown, Neil C. M.

    1989-01-01

    Looks at the usefulness of a stable realism for questions related to the description and understanding of art works. Explores two theories which may resolve the antagonism between representational meanings and their assertion as true properties of the work: (1) Wiggin's concept of authentic effect; and (2) Petit's theory of rectification and…

  3. Trusting Description: Authenticity, Accountability, and Archival Description Standards

    ERIC Educational Resources Information Center

    MacNeil, Heather

    2009-01-01

    It has been suggested that one of the purposes of archival description is to establish grounds for presuming the authenticity of the records being described. The article examines the implications of this statement by examining the relationship between and among authenticity, archival description, and archival accountability, assessing how this…

  4. Langevin description of nonequilibrium quantum fields

    NASA Astrophysics Data System (ADS)

    Gautier, F.; Serreau, J.

    2012-12-01

    We consider the nonequilibrium dynamics of a real quantum scalar field. We show the formal equivalence of the exact evolution equations for the statistical and spectral two-point functions with a fictitious Langevin process and examine the conditions under which a local Markovian dynamics is a valid approximation. In quantum field theory, the memory kernel and the noise correlator typically exhibit long time power laws and are thus highly nonlocal, thereby questioning the possibility of a local description. We show that despite this fact, there is a finite time range during which a local description is accurate. This requires the theory to be (effectively) weakly coupled. We illustrate the use of such a local description for studies of decoherence and entropy production in quantum field theory.

  5. Coulomb Blockade of the Conductivity of SiO{sub x} Films Due to One-Electron Charging of a Silicon Quantum Dot in a Chain of Electronic States

    SciTech Connect

    Efremov, M.D.; Kamaev, G.N.; Volodin, V.A.; Arzhannikova, S.A.; Kachurin, G.A.; Cherkova, S.G.; Kretinin, A.V.; Malyutina-Bronskaya, V.V.; Marin, D.V.

    2005-08-15

    The electrical characteristics of metal-oxide-semiconductor (MOS) structures with silicon nanoparticles embedded in silicon oxide have been studied. The nanocrystals are formed by decomposition of an oversaturated solid solution of implanted silicon during thermal annealing at a temperature of {approx}1000 deg. C. At liquid-nitrogen temperature, a stepped current-voltage characteristic is observed in a MOS structure consisting of Si nanocrystals in a SiO{sub 2} film. The stepped current-voltage characteristic is, for the first time, quantitatively described using a model in which charge transport occurs via a chain of local states containing a silicon nanocrystal. The presence of steps is found to be associated with one-electron charging of the silicon nanocrystal and Coulomb blockade of the probability of a hop from the nearest local state to the conducting chain. The local states in silicon dioxide are assumed to be related to an excess of silicon atoms. The presence of such states is confirmed by measurements of the differential conductance and capacitance. For MOS structures implanted with silicon, the differential capacitance and conductance are found to be higher, compared to the reference structures, in the range of biases exceeding 0.2 V. In the same bias range, the conductance is observed to decrease under ultraviolet irradiation due to a change in the population of the states in the conductivity chains.

  6. Theoretical study of one-electron bonds in a series of high-spin lithium-beryllium-hydrogen clusters: ?Valence shell single-electron repulsion? rule and electron localization function analysis

    NASA Astrophysics Data System (ADS)

    Chaquin, Patrick; Chevreau, Hilaire

    A series of high-spin clusters containing Li, H, and Be in which the valence shell molecular orbitals (MOs) are occupied by a single electron has been characterized using ab initio and density functional theory (DFT) calculations. A first type (5Li2, n+1LiHn+ (n = 2-5), 8Li2H6+) possesses only one electron pair in the lowest MO, with bond energies of ?3 kcal/mol. In a second type, all the MOs are singly occupied, which results in highly excited species that nevertheless constitute a marked minimum on their potential energy surface (PES). Thus, it is possible to design a larger panel of structures (8LiBe, 7Li2, 8Li2-, 4LiH+, 6BeH2+, n+3LiHn+ (n = 3, 4), n+2LiHn2+ (n = 4-6), 8Li2H2+, 9Li2H42+, 22Li3Be3 and 22Li6H63+), single-electron equivalent to doublet ?classical? molecules ranging from CO to C6H6. The geometrical structure is studied in relation to the valence shell single-electron repulsion (VSEPR) theory and the electron localization function (ELF) is analyzed, revealing a striking similarity with the corresponding structure having paired electrons.

  7. Multispectral Scanner (MSS) Instrument Description

    NASA Technical Reports Server (NTRS)

    Barker, J. L.; Banks, G.

    1984-01-01

    The MSS sensor image processing and resolution capabilities as well as a general system description are presented in chart form. Emphasis is placed on absolute radiometric calibration, video and wedge level timing sequence, focal plane dimensions, sampling sequence, and a description of the mirror coordinate systems.

  8. Descriptive approaches to landscape analysis

    Treesearch

    R. Burton Litton Jr.

    1979-01-01

    Descriptive landscape analyses include various procedures used to document visual/scenic resources. Historic and regional examples of landscape description represent desirable insight for contemporary professional inventory work. Routed and areal landscape inventories are discussed as basic tools. From them, qualitative and quantitative evaluations can be developed...

  9. Mission data system framework description

    NASA Technical Reports Server (NTRS)

    Meyer, K.; Rinker, G.; Dvorak, D.; Rosmussen, R.; Reinholttz, K.

    2002-01-01

    This document provides an overall description of the MDS Framework technology. Since the purpose is to provide a general reference for the frameworks, the descriptions are organized as compendium. This document does not provide guidance for how the MDS technology should be used.

  10. Logic synthesis from DDL description

    NASA Technical Reports Server (NTRS)

    Shiva, S. G.

    1980-01-01

    The implementation of DDLTRN and DDLSIM programs on SEL-2 computer system is reported. These programs were tested with DDL descriptions of various complexity. An algorithm to synthesize the combinational logic using the cells available in the standard IC cell library was formulated. The algorithm is implemented as a FORTRAN program and a description of the program is given.

  11. Towards Reproducible Descriptions of Neuronal Network Models

    PubMed Central

    Nordlie, Eilen; Gewaltig, Marc-Oliver; Plesser, Hans Ekkehard

    2009-01-01

    Progress in science depends on the effective exchange of ideas among scientists. New ideas can be assessed and criticized in a meaningful manner only if they are formulated precisely. This applies to simulation studies as well as to experiments and theories. But after more than 50 years of neuronal network simulations, we still lack a clear and common understanding of the role of computational models in neuroscience as well as established practices for describing network models in publications. This hinders the critical evaluation of network models as well as their re-use. We analyze here 14 research papers proposing neuronal network models of different complexity and find widely varying approaches to model descriptions, with regard to both the means of description and the ordering and placement of material. We further observe great variation in the graphical representation of networks and the notation used in equations. Based on our observations, we propose a good model description practice, composed of guidelines for the organization of publications, a checklist for model descriptions, templates for tables presenting model structure, and guidelines for diagrams of networks. The main purpose of this good practice is to trigger a debate about the communication of neuronal network models in a manner comprehensible to humans, as opposed to machine-readable model description languages. We believe that the good model description practice proposed here, together with a number of other recent initiatives on data-, model-, and software-sharing, may lead to a deeper and more fruitful exchange of ideas among computational neuroscientists in years to come. We further hope that work on standardized ways of describing—and thinking about—complex neuronal networks will lead the scientific community to a clearer understanding of high-level concepts in network dynamics, and will thus lead to deeper insights into the function of the brain. PMID:19662159

  12. Towards reproducible descriptions of neuronal network models.

    PubMed

    Nordlie, Eilen; Gewaltig, Marc-Oliver; Plesser, Hans Ekkehard

    2009-08-01

    Progress in science depends on the effective exchange of ideas among scientists. New ideas can be assessed and criticized in a meaningful manner only if they are formulated precisely. This applies to simulation studies as well as to experiments and theories. But after more than 50 years of neuronal network simulations, we still lack a clear and common understanding of the role of computational models in neuroscience as well as established practices for describing network models in publications. This hinders the critical evaluation of network models as well as their re-use. We analyze here 14 research papers proposing neuronal network models of different complexity and find widely varying approaches to model descriptions, with regard to both the means of description and the ordering and placement of material. We further observe great variation in the graphical representation of networks and the notation used in equations. Based on our observations, we propose a good model description practice, composed of guidelines for the organization of publications, a checklist for model descriptions, templates for tables presenting model structure, and guidelines for diagrams of networks. The main purpose of this good practice is to trigger a debate about the communication of neuronal network models in a manner comprehensible to humans, as opposed to machine-readable model description languages. We believe that the good model description practice proposed here, together with a number of other recent initiatives on data-, model-, and software-sharing, may lead to a deeper and more fruitful exchange of ideas among computational neuroscientists in years to come. We further hope that work on standardized ways of describing--and thinking about--complex neuronal networks will lead the scientific community to a clearer understanding of high-level concepts in network dynamics, and will thus lead to deeper insights into the function of the brain.

  13. Effect of fat level on the perception of five flavor chemicals in ice cream with or without fat mimetics by using a descriptive test.

    PubMed

    Liou, B K; Grün, I U

    2007-10-01

    Fat mimetics are commonly used in the manufacture of low-fat and fat-free ice creams. However, the use of fat mimetics affects flavor and texture characteristics of ice cream, which results in decreased overall acceptability by consumers. The initial objective of this study was to investigate the release behavior of 5 strawberry flavor compounds in ice creams with Simplesse((R)), Litesse((R)), and Litesse((R))/Simplesse((R)) mixes using descriptive analysis. Fat mimetics and flavor formulation significantly influenced the perception of Furaneoltrade mark (cooked sugar flavor), alpha-ionone (violet flavor), and gamma-undecalactone (peach flavor), but there was no interaction between ice cream type and flavor formulation for the 3 flavors. Furaneol and ethyl-3-methyl-3-phenylglycidate (candy flavor) were perceived more strongly in full-fat ice cream, while cis-3-hexen-1-ol (grassy flavor), alpha-ionone, and gamma-undecalactone were perceived more strongly in low-fat ice cream. Ice creams with Simplesse and full-fat ice cream had similar sensory characteristics, while ice creams with Litesse were similar to low-fat ice creams in flavor characteristics, and ice creams with Litesse/Simplesse mixes were closer in flavor profile to low-fat ice cream but had similar texture properties to those of full-fat ice cream. Simplesse was found to be a better fat mimetic for duplicating the flavor profiles and mouthfeel of full-fat ice cream.

  14. Redefinition of working aqueous two-phase systems: a generic description for prediction of the effective phase chemical composition for process control and biorecovery.

    PubMed

    Selvakumar, Pitchaivelu; Ling, Tau Chuan; Walker, Simon; Lyddiatt, Andrew

    2010-07-01

    Aqueous two-phase systems (ATPS) have been widely adopted for the combined purpose of solid liquid separation, and recovery and purification of bioproducts such as proteins, viruses and organelles from biological feedstocks and fermentation broth. However, in spite of potential advantages over other techniques applied to concentrated biological feedstocks, ATPS have been applied at process scale only by a few industries and research establishments. ATPS are sensitive to loading with modest to extreme quantities of biological feedstock due to the contribution of that material to phase formation in combination with the conventional phase-forming chemicals. This causes problem associated with the definition and manipulation of loaded working systems, which may be addresses as in the present study with the aid of distribution analysis of radiolabel led analytes (DARA) in representative process samples. The present study focussed on establishing a generic description for characterising ATPS loaded with biological feedstocks and the redefinition of the biological feedstock loaded system composition in terms of phase forming chemical equivalents. This evaluation will be useful to achieve ATPS process implementation where phase recycle/reuse is adopted without compromise to process operations and consistent protein recovery performance. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Copper-Catalyzed Aerobic Oxidations of Organic Molecules: Pathways for Two-Electron Oxidation with a Four-Electron Oxidant and a One-Electron Redox-Active Catalyst.

    PubMed

    McCann, Scott D; Stahl, Shannon S

    2015-06-16

    Selective oxidation reactions have extraordinary value in organic chemistry, ranging from the conversion of petrochemical feedstocks into industrial chemicals and polymer precursors to the introduction of heteroatom functional groups into pharmaceutical and agrochemical intermediates. Molecular oxygen (O2) would be the ideal oxidant for these transformations. Whereas many commodity-scale oxidations of simple hydrocarbon feedstocks employ O2 as an oxidant, methods for selective oxidation of more complex molecules bearing diverse functional groups are often incompatible with existing aerobic oxidation methods. The latter limitation provides the basis for our interest in the development of new catalytic transformations and the elucidation of mechanistic principles that underlie selective aerobic oxidation reactions. One challenge inherent in such methods is the incommensurate redox stoichiometry associated with the use of O2, a four-electron oxidant, in reactions that achieve two-electron oxidation of organic molecules. This issue is further complicated by the use of first-row transition-metal catalysts, which tend to undergo facile one-electron redox steps. In recent years, we have been investigating Cu-catalyzed aerobic oxidation reactions wherein the complexities just noted are clearly evident. This Account surveys our work in this area, which has emphasized three general classes of reactions: (1) single-electron-transfer reactions for oxidative functionalization of electron-rich substrates, such as arenes and heterocycles; (2) oxidative carbon-heteroatom bond-forming reactions, including C-H oxidations, that proceed via organocopper(III) intermediates; and (3) methods for aerobic oxidation of alcohols and amines that use Cu(II) in combination with an organic redox-active cocatalyst to dehydrogenate the carbon-heteroatom bond. These reaction classes demonstrate three different pathways to achieve two-electron oxidation of organic molecules via the cooperative

  16. C5′- and C3′-sugar radicals produced via photo-excitation of one-electron oxidized adenine in 2′-deoxyadenosine and its derivatives

    PubMed Central

    Adhikary, Amitava; Becker, David; Collins, Sean; Koppen, Jessica; Sevilla, Michael D.

    2006-01-01

    We report that photo-excitation of one-electron-oxidized adenine [A(-H)•] in dAdo and its 2′-deoxyribonucleotides leads to formation of deoxyribose sugar radicals in remarkably high yields. Illumination of A(-H)• in dAdo, 3′-dAMP and 5′-dAMP in aqueous glasses at 143 K leads to 80-100% conversion to sugar radicals at C5′ and C3′. The position of the phosphate in 5′- and 3′-dAMP is observed to deactivate radical formation at the site of substitution. In addition, the pH has a crucial influence on the site of sugar radical formation; e.g. at pH ∼5, photo-excitation of A(-H)• in dAdo at 143 K produces mainly C5′• whereas only C3′• is observed at high pH ∼12. 13C substitution at C5′ in dAdo yields 13C anisotropic couplings of (28, 28, 84) G whose isotropic component 46.7 G identifies formation of the near planar C5′•. A β-13C 16 G isotropic coupling from C3′• is also found. These results are found to be in accord with theoretically calculated 13C couplings at C5′ [DFT, B3LYP, 6-31(G) level] for C5′• and C3′•. Calculations using time-dependent density functional theory [TD-DFT B3LYP, 6-31G(d)] confirm that transitions in the near UV and visible induce hole transfer from the base radical to the sugar group leading to sugar radical formation. PMID:16537838

  17. EPR spin-trapping evidence for the direct, one-electron reduction of tert-butylhydroperoxide to the tert-butoxyl radical by copper(II): paradigm for a previously overlooked reaction in the initiation of lipid peroxidation.

    PubMed

    Jones, Clare M; Burkitt, Mark J

    2003-06-11

    Lipid peroxidation is often initiated using Cu(II) ions. It is widely assumed that Cu(II) oxidizes preformed lipid hydroperoxides to peroxyl radicals, which propagate oxidation of the parent fatty acid via hydrogen atom abstraction. However, the oxidation of alkyl hydroperoxides by Cu(II) is thermodynamically unfavorable. An alternative means by which Cu(II) ions could initiate lipid peroxidation is by their one-electron reduction of lipid hydroperoxides to alkoxyl radicals, which would be accompanied by the generation of Cu(III). We have investigated by EPR spectroscopy, in conjunction with the spin trap 5,5-dimethyl-1-pyrroline N-oxide, the reactions of various Cu(II) chelates with tert-butylhydroperoxide. Spectra contained signals from the tert-butoxyl, methyl, and methoxyl radical adducts. In many previous studies, the signal from the methoxyl adduct has been assigned incorrectly to the tert-butylperoxyl adduct, which is now known to be unstable, releasing the tert-butoxyl radical upon decomposition. This either is trapped by 5,5-dimethyl-1-pyrroline N-oxide or undergoes beta-scission to the methyl radical, which either is trapped or reacts with molecular oxygen to give, ultimately, the methoxyl radical adduct. By using metal chelates that are known to be specific in either their oxidation or reduction of tert-butylhydroperoxide (the Cu(II) complex of bathocuproine disulfonic acid and the Fe(II) complex of diethylenetriaminepentaacetic acid, respectively) for comparison, we have been able to deduce, from the relative concentrations of the three radical adducts, that the Cu(II) complexes tested each reduce tert-butylhydroperoxide directly to the tert-butoxyl radical. These findings suggest that a previously overlooked reaction, namely the direct reduction of preformed lipid hydroperoxides to alkoxyl radicals by Cu(II), may be responsible for the initiation of lipid peroxidation by Cu(II) ions.

  18. Probabilistic description of traffic flow

    NASA Astrophysics Data System (ADS)

    Mahnke, R.; Kaupužs, J.; Lubashevsky, I.

    2005-03-01

    A stochastic description of traffic flow, called probabilistic traffic flow theory, is developed. The general master equation is applied to relatively simple models to describe the formation and dissolution of traffic congestions. Our approach is mainly based on spatially homogeneous systems like periodically closed circular rings without on- and off-ramps. We consider a stochastic one-step process of growth or shrinkage of a car cluster (jam). As generalization we discuss the coexistence of several car clusters of different sizes. The basic problem is to find a physically motivated ansatz for the transition rates of the attachment and detachment of individual cars to a car cluster consistent with the empirical observations in real traffic. The emphasis is put on the analogy with first-order phase transitions and nucleation phenomena in physical systems like supersaturated vapour. The results are summarized in the flux-density relation, the so-called fundamental diagram of traffic flow, and compared with empirical data. Different regimes of traffic flow are discussed: free flow, congested mode as stop-and-go regime, and heavy viscous traffic. The traffic breakdown is studied based on the master equation as well as the Fokker-Planck approximation to calculate mean first passage times or escape rates. Generalizations are developed to allow for on-ramp effects. The calculated flux-density relation and characteristic breakdown times coincide with empirical data measured on highways. Finally, a brief summary of the stochastic cellular automata approach is given.

  19. Action description using point clouds

    NASA Astrophysics Data System (ADS)

    Liu, Wenping; Jiang, Yongfeng; Wang, Haili; Zhang, Liang

    2017-06-01

    An action description method named as Motion History Point Cloud (MHPC) is proposed in this paper. MHPC compresses an action into a three-dimensional point cloud in which depth information is required. In MHPC, the spatial coordinate channels are used to record the motion foreground, and the color channels are used to record the temporal variation. Due to containing depth information, MHPC can depict an action more meticulous than Motion History Image (MHI). MHPC can serve as a pre-processed input for various classification methods, such as Bag of Words and Deep Learning. An action recognition scheme is provided as an application example of MHPC. In this scheme, Harris3D detector and Fast Point Feature Histogram (FPFH) are used to extract and describe features from MHPC. Then, Bag of Words and multiple classification Support Vector Machine (SVM) are used to do action recognition. The experiments show that rich features can be extracted from MHPC to support the subsequent action recognition even after downsampling. The feasibility and effectiveness of MHPC are also verified by comparing the above scheme with two similar methods.

  20. [Descriptive analysis of work and trends in anaesthesiology from 2005 to 2006: quantitative and qualitative aspects of effects and evaluation of anaesthesia].

    PubMed

    Majstorović, Branislava M; Simić, Snezana; Milaković, Branko D; Vucović, Dragan S; Aleksić, Valentina V

    2010-01-01

    In anaesthesiology, economic aspects have been insufficiently studied. The aim of this paper was the assessment of rational choice of the anaesthesiological services based on the analysis of the scope, distribution, trend and cost. The costs of anaesthesiological services were counted based on "unit" prices from the Republic Health Insurance Fund. Data were analysed by methods of descriptive statistics and statistical significance was tested by Student's t-test and chi2-test. The number of general anaesthesia was higher and average time of general anaesthesia was shorter, without statistical significance (t-test, p = 0.436) during 2006 compared to the previous year. Local anaesthesia was significantly higher (chi2-test, p = 0.001) in relation to planned operation in emergency surgery. The analysis of total anaesthesiological procedures revealed that a number of procedures significantly increased in ENT and MFH surgery, and ophthalmology, while some reduction was observed in general surgery, orthopaedics and trauma surgery and cardiovascular surgery (chi2-test, p = 0.000). The number of analgesia was higher than other procedures (chi2-test, p = 0.000). The structure of the cost was 24% in neurosurgery, 16% in digestive (general) surgery,14% in gynaecology and obstetrics, 13% in cardiovascular surgery and 9% in emergency room. Anaesthesiological services costs were the highest in neurosurgery, due to the length anaesthesia, and digestive surgery due to the total number of general anaesthesia performed. It is important to implement pharmacoeconomic studies in all departments, and to separate the anaesthesia services for emergency and planned operations. Disproportions between the number of anaesthesia, surgery interventions and the number of patients in surgical departments gives reason to design relation database.

  1. Tactical Planning Workstation Software Description

    DTIC Science & Technology

    1990-09-01

    Tactical Planning Workstation Software Description 12. PERSONAL AUTHOR(S) Packard, Bruce R. 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year...3-7 3-2. Unit type codes....................................3-7 3-3. Battle function codes ................................ 3-8 3-4...3-9 3-7. Control measure types ...............................3-11 3-8. Product description files

  2. Descriptional Composition of Compiler Components

    DTIC Science & Technology

    1996-09-01

    matching [47]. A more declarative description may permit widely di erent execution models . For example, the same description could be implemented both as a...object is described in a single place rather than requiring two speci cations. In practice, however, the implementation model used by Prolog often makes...possible to directly model the attribution of trees in such languages. In fact, it is impossible to distinguish trees from directed acyclic graphs. This

  3. A royal description of madness.

    PubMed

    Ottilingam, Somasundaram; Tejus, Murthy; Vijaya, Raghavan

    2016-08-01

    The search for the description of mental illness in the community is an interesting pastime and has been attempted by many psychiatrists. The present writer has described an instance in the Tamil literature of the 2nd century CE in the Tamil Buddhist epic, Manimekalai. Presently, is given another description from the stylus of the Tamil Pallava king, Mahendravarman of the 6th century CE from his farcical drama of Mattavilasa Prahasana. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Comparison of the One-electron Oxidations of CO-Bridged vs Unbridged Bimetallic Complexes: Electron-transfer Chemistry of Os2Cp2(CO)4 and Os2Cp*2(μ-CO)2(CO)2 (Cp = η5-C5H5, Cp* = η5-C5Me5)

    SciTech Connect

    Laws, Derek R.; Bullock, R. Morris; Lee, Richmond; Huang, Kuo-Wei; Geiger, William J.

    2014-09-22

    The one-electron oxidations of two dimers of half-sandwich osmium carbonyl complexes have been examined by electrochemistry, spectro-electrochemistry, and computational methods. The all-terminal carbonyl complex Os2Cp2(CO)4 (1, Cp = η5-C5H5) undergoes a reversible one-electron anodic reaction at E1/2 = 0.41 V vs ferrocene in CH2Cl2/0.05 M [NBu4][B(C6F5)4], giving a rare example of a metal-metal bonded radical cation unsupported by bridging ligands. The IR spectrum of 1+ is consistent with an approximately 1:1 mixture of anti and gauche structures for the 33 e- radical cation in which it has retained all-terminal bonding of the CO ligands. DFT calculations, including orbital-occupancy-perturbed Mayer bond-order analyses, show that the HOMOs of anti-1 and gauche-1 are metal-ligand delocalized. Removal of an electron from 1 has very little effect on the Os-Os bond order, accounting for the resistance of 1+ to heterolytic cleavage. The Os-Os bond distance is calculated to decrease by 0.10 Å and 0.06 Å as a consequence of one-electron oxidation of anti-1 and gauche-1, respectively. The CO-bridged complex Os2Cp*2(μ-CO)2(CO)2 (Cp* = η5-C5Me5), trans-2, undergoes a more facile oxidation, E1/2 = - 0.11 V, giving a persistent radical cation shown by solution IR analysis to preserve its bridged-carbonyl structure. However, ESR analysis of frozen solutions of 2+ is interpreted in terms of the presence of two isomers, most likely anti-2+ and trans-2+, at low temperature. Calculations show that the HOMO of trans-2 is highly delocalized over the metal-ligand framework, with the bridging carbonyls accounting for about half of the orbital makeup. The Os-Os bond order again changes very little with removal of an electron, and the Os-Os bond length actually undergoes minor shortening. Calculations suggest that the second isomer of 2+ has both the trans CO-bridged and the anti all-terminal CO structures. DRL and WEG acknowledge the support of the National Science Foundation under

  5. BICEP2 in corpuscular description of inflation

    SciTech Connect

    Dvali, G.; Gomez, C.

    2015-03-15

    A corpuscular quantum description of inflation shows that there is no fundamental problem with trans-Planckian excursions of the inflaton field up to about 100 Planck masses, with the upper bound coming from the corpuscular quantum effects. In this description, the r parameter measures the ratio of occupation numbers of gravitons versus inflatons, which, according to BICEP2, was roughly a half at the time of 60 e-foldings prior to the end of inflation. We stress that in a non-Wilsonian UV self-completion of gravity, any trans-Planckian mode coupled to the inflaton is a black hole. Unlike the Wilsonian case, integrating them out gives an exponentially suppressed effect and is unable to prevent trans-Planckian excursions of the inflaton field.

  6. The effect of using NHS number as the unique identifier for patients who self-harm: a multi-centre descriptive study.

    PubMed

    Cooper, Jayne; Murphy, Elizabeth; Bergen, Helen; Casey, Deborah; Hawton, Keith; Owens, David; Lilley, Rachael; Noble, Rachael; Kapur, Navneet

    2007-09-21

    Processing personal data for research purposes and the requirement of anonymity has been the subject of recent debate. We aimed to determine the proportion of individuals who present to emergency departments with non-fatal suicidal behavior where an NHS number has been successfully traced and to investigate the characteristics of patients associated with non-capture. This was a descriptive study of people attending after self-harm using allocation of NHS numbers as main outcome measurement. Data from the Multicentre Monitoring of Self-Harm Project from 3 centres in England were used to identify consecutive patients (N = 3000) who were treated in six emergency departments in Oxford, Manchester and Leeds in 2004 and 2005 following self-harm. NHS number was available between 55-73% of individuals across centres. Characteristics associated with non-recording of NHS number in more than one centre included those from ethnic minority groups (Oxford: chi-squared statistic = 13.6, df = 3, p = 0.004; Manchester: chi-squared statistic = 13.6, df = 3, p

  7. A Cross-Sectional Descriptive Study of Graduate Students' Perceptions of Learning Effectiveness in Face-to-Face and Online Courses

    ERIC Educational Resources Information Center

    Evans, Nicole Stayton

    2013-01-01

    The measurement of student perceptions of learning effectiveness is often used as a tool at universities to enhance the quality of course offerings. The recent growth in online course offerings creates new challenges in evaluating learning effectiveness. This study used three principles of adult learning theory, foundation, self-concept, and…

  8. A Cross-Sectional Descriptive Study of Graduate Students' Perceptions of Learning Effectiveness in Face-to-Face and Online Courses

    ERIC Educational Resources Information Center

    Evans, Nicole Stayton

    2013-01-01

    The measurement of student perceptions of learning effectiveness is often used as a tool at universities to enhance the quality of course offerings. The recent growth in online course offerings creates new challenges in evaluating learning effectiveness. This study used three principles of adult learning theory, foundation, self-concept, and…

  9. Skylab: Program Description

    NASA Technical Reports Server (NTRS)

    1971-01-01

    In 1973 three Americans will embark on the first of a series of Earth orbiting missions using Skylab, the first United States vehicle created specifically to enable man to live and work in space for extended periods. Sky lab is a program dedicated to the use of space and its unique environment and vantage point to increase our knowledge and understanding of the Earth's importance to man's well-being and man's influence on Earth's ecology. Sky lab will also be a major step in manned space flight. Habitation by the first crew will double our previous man-in-space duration (Gemini VII) and the second visit will redouble that duration. It will, in effect, create a bridge between the development flights of the 60s and the long duration operational space flights of the future. To accomplish its mission, Sky lab will be placed in Earth orbit and will be visited and inhabited by three different crews during an eight-month period. While successfully inhabiting and operating the vehicle for one- and two-month continuous periods, these crews will obtain data in areas pertinent to the man/Earth relationship and to long duration space flight. Data will be acquired by Skylab primarily through the conduct of "experiments." Four categories of investigation are planned. These are summarized in the following paragraphs.

  10. Toward Descriptive Standards. Report and Recommendations of the Canadian Working Group on Archival Descriptive Standards.

    ERIC Educational Resources Information Center

    Bureau of Canadian Archivists, Ottawa (Ontario).

    Building upon recent efforts of Canadian archivists to improve the development and application of technology in order to achieve more effective control of and access to their holdings, this report contains the deliberations and recommendations of the Canadian Working Group on Archival Descriptive Standards, which held seven meetings between April…

  11. Use of Infrared Spectrometry to Determine the Effect of Temperature on the Description Rates of Trichloroethylene from Plastic Clay 98b

    DTIC Science & Technology

    1994-08-01

    hazardous waste that may cause severe environmental and health effects. If left untreated, these hazardous substan-es may pQllute the drinking water...as a potential health hazard in drinking waters ano is considered as the most prevalent of volatile organic compound contaminants. 8 Furthermore, TCE...II. Background Theory . . . . . . . . . . . . . 13 2.1 Introduction . . . . . . . . . . . . . . i3 2.2 TCE Adverse Health Effects . . . . . . . . . 14

  12. Identification of Evidence for Key Parameters in Decision-Analytic Models of Cost Effectiveness: A Description of Sources and a Recommended Minimum Search Requirement.

    PubMed

    Paisley, Suzy

    2016-06-01

    This paper proposes recommendations for a minimum level of searching for data for key parameters in decision-analytic models of cost effectiveness and describes sources of evidence relevant to each parameter type. Key parameters are defined as treatment effects, adverse effects, costs, resource use, health state utility values (HSUVs) and baseline risk of events. The recommended minimum requirement for treatment effects is comprehensive searching according to available methodological guidance. For other parameter types, the minimum is the searching of one bibliographic database plus, where appropriate, specialist sources and non-research-based and non-standard format sources. The recommendations draw on the search methods literature and on existing analyses of how evidence is used to support decision-analytic models. They take account of the range of research and non-research-based sources of evidence used in cost-effectiveness models and of the need for efficient searching. Consideration is given to what constitutes best evidence for the different parameter types in terms of design and scientific quality and to making transparent the judgments that underpin the selection of evidence from the options available. Methodological issues are discussed, including the differences between decision-analytic models of cost effectiveness and systematic reviews when searching and selecting evidence and comprehensive versus sufficient searching. Areas are highlighted where further methodological research is required.

  13. Effectiveness of two intensive treatment methods for smoking cessation and relapse prevention in patients with coronary heart disease: study protocol and baseline description

    PubMed Central

    2012-01-01

    Background There is no more effective intervention for secondary prevention of coronary heart disease than smoking cessation. Yet, evidence about the (cost-)effectiveness of smoking cessation treatment methods for cardiac inpatients that also suit nursing practice is scarce. This protocol describes the design of a study on the (cost-)effectiveness of two intensive smoking cessation interventions for hospitalised cardiac patients as well as first results on the inclusion rates and the characteristics of the study population. Methods/design An experimental study design is used in eight cardiac wards of hospitals throughout the Netherlands to assess the (cost-)effectiveness of two intensive smoking cessation counselling methods both combined with nicotine replacement therapy. Randomization is conducted at the ward level (cross-over). Baseline and follow-up measurements after six and 12 months are obtained. Upon admission to the cardiac ward, nurses assess patients’ smoking behaviour, ensure a quit advice and subsequently refer patients for either telephone counselling or face-to-face counselling. The counselling interventions have a comparable structure and content but differ in provider and delivery method, and in duration. Both counselling interventions are compared with a control group receiving no additional treatment beyond the usual care. Between December 2009 and June 2011, 245 cardiac patients who smoked prior to hospitalisation were included in the usual care group, 223 in the telephone counselling group and 157 in the face-to-face counselling group. Patients are predominantly male and have a mean age of 57 years. Acute coronary syndrome is the most frequently reported admission diagnosis. The ultimate goal of the study is to assess the effects of the interventions on smoking abstinence and their cost-effectiveness. Telephone counselling is expected to be more (cost-)effective in highly motivated patients and patients with high SES, whereas face

  14. Beyond transition state theory: accurate description of nuclear quantum effects on the rate and equilibrium constants of chemical reactions using Feynman path integrals.

    PubMed

    Vanícek, Jirí

    2011-01-01

    Nuclear tunneling and other nuclear quantum effects have been shown to play a significant role in molecules as large as enzymes even at physiological temperatures. I discuss how these quantum phenomena can be accounted for rigorously using Feynman path integrals in calculations of the equilibrium and kinetic isotope effects as well as of the temperature dependence of the rate constant. Because these calculations are extremely computationally demanding, special attention is devoted to increasing the computational efficiency by orders of magnitude by employing efficient path integral estimators.

  15. CANISTER HANDLING FACILITY DESCRIPTION DOCUMENT

    SciTech Connect

    J.F. Beesley

    2005-04-21

    The purpose of this facility description document (FDD) is to establish requirements and associated bases that drive the design of the Canister Handling Facility (CHF), which will allow the design effort to proceed to license application. This FDD will be revised at strategic points as the design matures. This FDD identifies the requirements and describes the facility design, as it currently exists, with emphasis on attributes of the design provided to meet the requirements. This FDD is an engineering tool for design control; accordingly, the primary audience and users are design engineers. This FDD is part of an iterative design process. It leads the design process with regard to the flowdown of upper tier requirements onto the facility. Knowledge of these requirements is essential in performing the design process. The FDD follows the design with regard to the description of the facility. The description provided in this FDD reflects the current results of the design process.

  16. Deriving Descriptions of the Mind.

    DTIC Science & Technology

    1987-07-07

    AiB6 647 DERIVING DESCRIPTIONS OF THE MIND (U) CARNEGIE-MELLON / UNIV PITTSBURGH PA DEPT OF PSYCHOLOGY S GARLICK ET AL 87 JUL 87 PCG-7 N88914-86-K...8149 UNCLASSIFIED F/G 12/9 MI. mN hEhhhh 1൘ ill 2.2 IIll O p4IuI 3. , ,- flhCILLCM Deriving Descriptions of the Mind Technical Report PCG-7 4 Steve...OCT 22 7 PSYCHOLOGY -6Apptoved I’o1 ubi -4V D~~~ifbuto~Iu1 * Carnegie-Mellon University Deriving Descriptions of the Mind Technical Report PCG-7 Steve

  17. Micropolar continuum in spatial description

    NASA Astrophysics Data System (ADS)

    Ivanova, Elena A.; Vilchevskaya, Elena N.

    2016-11-01

    Within the spatial description, it is customary to refer thermodynamic state quantities to an elementary volume fixed in space containing an ensemble of particles. During its evolution, the elementary volume is occupied by different particles, each having its own mass, tensor of inertia, angular and linear velocities. The aim of the present paper is to answer the question of how to determine the inertial and kinematic characteristics of the elementary volume. In order to model structural transformations due to the consolidation or defragmentation of particles or anisotropic changes, one should consider the fact that the tensor of inertia of the elementary volume may change. This means that an additional constitutive equation must be formulated. The paper suggests kinetic equations for the tensor of inertia of the elementary volume. It also discusses the specificity of the inelastic polar continuum description within the framework of the spatial description.

  18. Description du langage scientifique (Description of Scientific Language)

    ERIC Educational Resources Information Center

    Widdowson, H. G.

    1977-01-01

    A description of scientific language using three approaches: text, textualization, and discourse. Scientific discourse is analogous to universal deep structure; text, to surface variations in diverse languages; and textualization, to transformational processes. The relationship of the primary and secondary (scientific) cultures and their languages…

  19. Auteur Description: From the Director's Creative Vision to Audio Description

    ERIC Educational Resources Information Center

    Szarkowska, Agnieszka

    2013-01-01

    In this report, the author follows the suggestion that a film director's creative vision should be incorporated into Audio description (AD), a major technique for making films, theater performances, operas, and other events accessible to people who are blind or have low vision. The author presents a new type of AD for auteur and artistic films:…

  20. Auteur Description: From the Director's Creative Vision to Audio Description

    ERIC Educational Resources Information Center

    Szarkowska, Agnieszka

    2013-01-01

    In this report, the author follows the suggestion that a film director's creative vision should be incorporated into Audio description (AD), a major technique for making films, theater performances, operas, and other events accessible to people who are blind or have low vision. The author presents a new type of AD for auteur and artistic films:…

  1. The Effectiveness of Corpus-Based Approach to Language Description in Creating Corpus-Based Exercises to Teach Writing Personal Statements

    ERIC Educational Resources Information Center

    Almutairi, Norah Dhawi

    2016-01-01

    Using corpora in language teaching has revolutionized language research with its "authentic" appeal. Corpus tools have enabled linguistic researchers and teachers to investigate actual usages and the characteristics of certain genres in order to improve syllabus design and infer more effective classroom exercises. From this perspective,…

  2. The Effect Of Oral Description In Complementing Animated Instruction In A Web-based Learning Environment On Undergraduate Students Achievement Of Different Educational Objectives

    ERIC Educational Resources Information Center

    Swain, Jeff; Munyofu, Mine; Kidwai, Khusro; Lin, Huifen; Ausman, Bradley; Dwyer, Francis

    2004-01-01

    The purpose of this study was to test the principle of modality by using audio to deliver verbal information when that information is designed to support non-verbal information such as animations in a computer-based lesson. This was done by comparing the effect of two types of audio support mechanisms- a simple support mechanism consisting of…

  3. The Effects of a First Grader's Participation in a Writer's Workshop on Their Ability To Become More Confident and More Descriptive Writers.

    ERIC Educational Resources Information Center

    Bayer, Robin Alyse

    Researchers believe that writing, and the writing process, are integral parts of any grade level curriculum. Since Writer's Workshop is an essential part of this process, an examination of the effects of first graders' participation in Writer's Workshop was studied to determine whether or not this enabled them to become more confident writers, and…

  4. A Descriptive Case Study: Effects of a School-Based Intervention Program and Family Involvement to Promote Healthy Lifestyles in Adolescents

    ERIC Educational Resources Information Center

    Wall, Joyce E. M.

    2013-01-01

    With an increasing amount of overweight children, especially among racial and ethnic minorities, effective population-level interventions are urgently needed (Wang et al., 2006). The purpose of this study was to provide insight into nutritional and physical activity intervention programs at a Connecticut public school in an urban setting.…

  5. Aerosol indirect effect on the grid-scale clouds in the two-way coupled WRF-CMAQ: model description, development, evaluation and regional analysis

    EPA Science Inventory

    This study implemented first, second and glaciations aerosol indirect effects (AIE) on resolved clouds in the two-way coupled WRF-CMAQ modeling system by including parameterizations for both cloud drop and ice number concentrations on the basis of CMAQ predicted aerosol distribu...

  6. A Descriptive Case Study: Effects of a School-Based Intervention Program and Family Involvement to Promote Healthy Lifestyles in Adolescents

    ERIC Educational Resources Information Center

    Wall, Joyce E. M.

    2013-01-01

    With an increasing amount of overweight children, especially among racial and ethnic minorities, effective population-level interventions are urgently needed (Wang et al., 2006). The purpose of this study was to provide insight into nutritional and physical activity intervention programs at a Connecticut public school in an urban setting.…

  7. Aerosol indirect effect on the grid-scale clouds in the two-way coupled WRF-CMAQ: model description, development, evaluation and regional analysis

    EPA Science Inventory

    This study implemented first, second and glaciations aerosol indirect effects (AIE) on resolved clouds in the two-way coupled WRF-CMAQ modeling system by including parameterizations for both cloud drop and ice number concentrations on the basis of CMAQ predicted aerosol distribu...

  8. Description of the time course of the prolactin suppressant effect of the dopamine agonist CQP201-403 by an integrated pharmacokinetic-pharmacodynamic model.

    PubMed

    Grevel, J; Brownell, J; Steimer, J L; Gaillard, R C; Rosenthaler, J

    1986-07-01

    Six male volunteers (mean age 24 years) received a single oral dose of 0.025 mg CQP201-403 and placebo in a randomised double-blind crossover design. Fifteen plasma samples were collected over 48 h and were assayed by radioimmunoassay for drug substance and prolactin (PRL). Three of the samples were drawn during sleep on the first study day. The pharmacological effect (E%) of CQP201-403 was expressed as reduction in plasma PRL levels. The pharmacokinetic (PK)-pharmacodynamic (PD) model consisted of two kinetic compartments and an effect compartment linked to the central compartment. A sigmoid Emax model (Hill equation) described the relationship between the drug concentration in the effect compartment and E%. Curve-fitting of PK and PD data provided individual parameter estimates which served to generate computer-simulated PK and PD profiles after single and multiple doses in order to: investigate the in vivo concentration-effect relationship; evaluate the consequence of dosage reduction on the steady-state PD profile; and study the robustness of the response to changes in drug potency and bioavailability.

  9. Description of the time course of the prolactin suppressant effect of the dopamine agonist CQP201-403 by an integrated pharmacokinetic-pharmacodynamic model.

    PubMed Central

    Grevel, J; Brownell, J; Steimer, J L; Gaillard, R C; Rosenthaler, J

    1986-01-01

    Six male volunteers (mean age 24 years) received a single oral dose of 0.025 mg CQP201-403 and placebo in a randomised double-blind crossover design. Fifteen plasma samples were collected over 48 h and were assayed by radioimmunoassay for drug substance and prolactin (PRL). Three of the samples were drawn during sleep on the first study day. The pharmacological effect (E%) of CQP201-403 was expressed as reduction in plasma PRL levels. The pharmacokinetic (PK)-pharmacodynamic (PD) model consisted of two kinetic compartments and an effect compartment linked to the central compartment. A sigmoid Emax model (Hill equation) described the relationship between the drug concentration in the effect compartment and E%. Curve-fitting of PK and PD data provided individual parameter estimates which served to generate computer-simulated PK and PD profiles after single and multiple doses in order to: investigate the in vivo concentration-effect relationship; evaluate the consequence of dosage reduction on the steady-state PD profile; and study the robustness of the response to changes in drug potency and bioavailability. PMID:3755608

  10. A Description and Analysis of the Perspectives on Leadership Effectiveness of African-American Student Leaders at the University of New Mexico. A Qualitative Research Study.

    ERIC Educational Resources Information Center

    Kustaa, Friedrich Freddy

    This report concerns a qualitative study on African-American leadership effectiveness as perceived and defined by African-American student leaders at the University of New Mexico (Albuquerque). Six African-American student leaders (three males and three females) participated in-depth interviews. The interviews were audiorecorded and transcribed.…

  11. Using plan reasoning in the generation of plan descriptions

    SciTech Connect

    Young, R.M.

    1996-12-31

    Previous work on the generation of natural language descriptions of complex activities has indicated that the unwieldy amount of text needed to describe complete plans makes for ineffective and unnatural descriptions. We argue here that concise and effective text descriptions of plans can be generated by exploiting a model of the hearer`s plan reasoning capabilities. We define a computational model of the hearer`s interpretation process that views the interpretation of plan descriptions as refinement search through a space of partial plans. This model takes into account the hearer`s plan preferences and the resource limitations on her reasoning capabilities to determine the completed plans she will construct from a given partial description.

  12. [Effectiveness of cognitive-behavioral treatment in social phobia: a description of the results obtained in a public mental health service].

    PubMed

    Leveni, Daniela; Piacentini, Daniele; Campana, Arturo

    2002-01-01

    Cognitive Behavioural Therapy for the treatment of Social Phobia has proved effective through several controlled trials and meta-analyses. In spite of this the CBT has not spread in clinical field yet. Therefore our aim was to verify the effectiveness of the CBT in a public mental health service and to compare our results with those described by experimental research. Participants were 11 public mental health center clients, with a primary diagnosis of Social Phobia (according to DSM-IV criteria). The transportability of CBT to a common clinical setting was examined comparing treatment outcome data, at the end of the treatment and at a six months follow up, with results described in controlled efficacy studies. We employed self completion rating scales relating to both general health conditions and life satisfaction (SF36) and trend of symptoms (LSPS). Moreover we recorded the Clinical Global Impression (CGI) and Patient's Global Impression (PGI). Despite differences in setting, clients and treatment providers, both the magnitude of change from pre-treatment and maintenance of change at a six months follow up were comparable with the parallel findings in the efficacy studies. The results attest the effectiveness of CBT even in a public mental health center setting so, in consideration of the fact that social phobia is a very common disease and involve high degree of severity, chronicity and disability, we hope that this effectual and relatively cheap therapy will be routinely applied in public mental health services.

  13. Emplacement Drift System Description Document

    SciTech Connect

    Eric Loros

    2001-07-31

    The Emplacement Drift System is part of the Engineered Barrier System and provides the interface between the various waste package (WP) systems and the Ground Control System. In conjunction with the various WPs, the Emplacement Drift System limits the release and transport of radionuclides from the WP to the Natural Barrier following waste emplacement. Collectively, the Emplacement Drift System consists of the structural support hardware (emplacement drift invert and WP emplacement pallet) and any performance-enhancing barriers (drip shields and invert ballast) installed or placed in the emplacement drifts. The Emplacement Drift System is entirely located within the emplacement drifts in the subsurface portion of the Monitored Geologic Repository (MGR); specifically, it is physically bounded by the Subsurface Facility System, the Ground Support System, and the Natural Barrier. The Emplacement Drift System supports the key MGR functions of limiting radionuclide release to the Natural Barrier, minimizing the likelihood of a criticality external to the WPs, limiting natural and induced environmental effects, and providing WP support. The Emplacement Drift System limits radionuclide release to the Natural Barrier by controlling the movement of radionuclides within the emplacement drift and to the Natural Barrier, and by limiting water contact with the WPs. The Emplacement Drift System provides physical support and barriers for emplaced WPs that reduce water contact. The Emplacement Drift WP spacing supports the thermal loading performance by complimenting drift layout and orientation as described in the system description document for the Subsurface Facility System. The Emplacement Drift System supports the WP and also provides an environment that aids in enhancing WP confinement performance. As part of the Engineered Barrier System, the Emplacement Drift System interfaces with the WP systems. The Emplacement Drift System also interfaces with the Natural Barrier

  14. Comprehensive review of the evidence regarding the effectiveness of community-based primary health care in improving maternal, neonatal and child health: 1. rationale, methods and database description.

    PubMed

    Perry, Henry B; Rassekh, Bahie M; Gupta, Sundeep; Wilhelm, Jess; Freeman, Paul A

    2017-06-01

    Community-based primary health care (CBPHC) is an approach used by health programs to extend preventive and curative health services beyond health facilities into communities and even down to households. Evidence of the effectiveness of CBPHC in improving maternal, neonatal and child health (MNCH) has been summarized by others, but our review gives particular attention to not only the effectiveness of specific interventions but also their delivery strategies at the community level along with their equity effects. This is the first article in a series that summarizes and analyzes the assessments of programs, projects, and research studies (referred to collectively as projects) that used CBPHC to improve MNCH in low- and middle-income countries. The review addresses the following questions: (1) What kinds of projects were implemented? (2) What were the outcomes of these projects? (3) What kinds of implementation strategies were used? (4) What are the implications of these findings? 12 166 reports were identified through a search of articles in the National Library of Medicine database (PubMed). In addition, reports in the gray literature (available online but not published in a peer-reviewed journal) were also reviewed. Reports that describe the implementation of one or more community-based interventions or an integrated project in which an assessment of the effectiveness of the project was carried out qualified for inclusion in the review. Outcome measures that qualified for inclusion in the review were population-based indicators that defined some aspect of health status: changes in population coverage of evidence-based interventions or changes in serious morbidity, in nutritional status, or in mortality. 700 assessments qualified for inclusion in the review. Two independent reviewers completed a data extraction form for each assessment. A third reviewer compared the two data extraction forms and resolved any differences. The maternal interventions assessed

  15. Quantitative description of the effect of stratification on dormancy release of grape seeds in response to various temperatures and water contents.

    PubMed

    Wang, W Q; Song, S Q; Li, S H; Gan, Y Y; Wu, J H; Cheng, H Y

    2009-01-01

    The effect of stratification on dormancy release of grape seeds crossing from the sub- to the supraoptimal range of temperatures and water contents was analysed by modified threshold models. The stratification impacted on dormancy release in three different ways: (i) dormancy was consistently released with prolonged stratification time when stratified at temperatures of <15 degrees C; (ii) at 15 degrees C and 20 degrees C, the stratification effect initially increased, and then decreased with extended time; and (iii) stratification at 25 degrees C only reduced germinable seeds. These behaviours indicated that stratification could not only release primary dormancy but also induce secondary dormancy in grape seed. The rate of dormancy release changed linearly in two phases, while induction increased exponentially with increasing temperature. The thermal time approaches effectively quantified dormancy release only at suboptimal temperature, but a quantitative method to integrate the occurrence of dormancy release and induction at the same time could describe it well at either sub- or supraoptimal temperatures. The regression with the percentage of germinable seeds versus stratification temperature or water content within both the sub- and supraoptimal range revealed how the optimal temperature (T(so)) and water content (W(so)) for stratification changed. The T(so) moved from 10.6 degrees C to 5.3 degrees C with prolonged time, while W(so) declined from >0.40 g H2O g DW(-1) at 5 degrees C to approximately 0.23 g H2O g DW(-1) at 30 degrees C. Dormancy release in grape seeds can occur across a very wide range of conditions, which has important implications for their ability to adapt to a changeable environment in the wild.

  16. Description of extended pre-harvest pig Salmonella surveillance-and-control programme and its estimated effect on food safety related to pork.

    PubMed

    Alban, L; Barfod, K; Petersen, J V; Dahl, J; Ajufo, J C; Sandø, G; Krog, H H; Aabo, S

    2010-11-01

    Salmonella in pork can be combated during pre- or post-harvest. For large slaughterhouses, post-harvest measures like decontamination might be cost-effective while this is less likely with small-to-medium sized slaughterhouses. In this study, pre-harvest measures might be more relevant. We describe an extended surveillance-and-control programme for Salmonella in finisher pigs, which, to establish equivalence to the Swedish control programme, is intended for implementation on the Danish island, Bornholm. The effect of the programme on food safety was estimated by analysing Salmonella data from pig carcasses originating from herds that would have qualified for the programme during 2006-2008. Food safety was interpreted as prevalence of Salmonella on carcasses as well as the estimated number of human cases of salmonellosis related to pork produced within the programme. Data from the Danish Salmonella programme were obtained from Bornholm. We used a simulation model developed to estimate the number of human cases based on the prevalence of Salmonella on carcass swabs. Herds are only accepted in the programme if they have one or less seropositive sample within the previous 6 months. In this way, the Salmonella load is kept to a minimum. The programme is not yet in operation and pigs that qualify for the programme are currently mixed at slaughter with those that do not qualify. Therefore, we had to assess the impact on the carcass prevalence indirectly. The prevalence of Salmonella in carcass swabs among qualifying herds was 0.46% for the 3 years as a whole, with 2006 as the year with highest prevalence. According to the simulation the expected number of human cases relating to pork produced within the programme was below 10. When the programme is in operation, an extra effect of separating pigs within the programme from those outside is expected to lower the prevalence of Salmonella even further.

  17. Developmental Kindergarten: Definition and Description.

    ERIC Educational Resources Information Center

    Virginia State Dept. of Education, Richmond.

    This paper sets forth a definition and operational description of a developmental program that should be of use as a guide, especially to Virginia's teachers and administrators. Also included in the paper are kindergarten curriculum objectives in the areas of language arts, mathematics, science, art, social studies, family life, health, mental…

  18. Phantom vision: a graphic description.

    PubMed

    Maloof, Anthony J

    2004-01-01

    An 80-year-old man, who is an experienced artist, underwent orbital exenteration for invasive squamous cell carcinoma. After exenteration, the patient noted a persistent, colored visual phenomenon. The phantom vision continued unchanged to 9 months after surgery (the time of writing), when the patient presented a graphic and written description of phantom vision.

  19. Natural Language Description of Emotion

    ERIC Educational Resources Information Center

    Kazemzadeh, Abe

    2013-01-01

    This dissertation studies how people describe emotions with language and how computers can simulate this descriptive behavior. Although many non-human animals can express their current emotions as social signals, only humans can communicate about emotions symbolically. This symbolic communication of emotion allows us to talk about emotions that we…

  20. Natural Language Description of Emotion

    ERIC Educational Resources Information Center

    Kazemzadeh, Abe

    2013-01-01

    This dissertation studies how people describe emotions with language and how computers can simulate this descriptive behavior. Although many non-human animals can express their current emotions as social signals, only humans can communicate about emotions symbolically. This symbolic communication of emotion allows us to talk about emotions that we…

  1. Empirical description of chiral autocatalysis.

    PubMed

    Micskei, Karoly; Póta, György; Caglioti, Luciano; Palyi, Gyula

    2006-05-11

    The only known example of chiral autocatalysis is the alkylation of N-heterocyclic aldehydes with iPr(2)Zn (Soai reaction). The mechanism and some details of this reaction are not yet clear. An empirical formula is proposed here for the description of this chiral autocatalytic reaction. This formula allows the calculation of some very informative parameters.

  2. Restoration of Descriptive Inorganic Chemistry.

    ERIC Educational Resources Information Center

    Gorman, Mel

    1983-01-01

    The movement to reinstate systematic inorganic reaction (descriptive) chemistry into the curriculum is gaining momentum. Offers suggestions and strategies showing that the change is desirable and easy, even for instructors with little experience with systematic fundamental and industrial inorganic chemistry. (Author/JN)

  3. Marketing and Merchandising, Course Description.

    ERIC Educational Resources Information Center

    Boyer, Jerome L.; Anderson, Floyd L.

    This course description was developed by educators for use at the Work Opportunity Center which was established to teach high school dropouts and/or hard-core unemployed youth. The ultimate objectives of the marketing and merchandising curriculum are to prepare students for careers in distribution and to assist them in graduating from high school.…

  4. Depressive illness in teens and preteens and effectiveness of the RADS-2 as a first-stage assessment. Part 1: Descriptive paper.

    PubMed

    Weber, Scott

    2009-08-01

    Measurement of the characteristics and severity of depression in adolescence is an emerging science. During patient assessment, or if using first-stage screening measures in practice, nurses must be confident that these instruments demonstrate high levels of accuracy in capturing the specific features of depressive symptoms expressed in diverse individuals. A review of the scientific literature of depressive illness and its assessment in teens and preteens is presented. The Reynolds Adolescent Depression Scale-Revised (RADS-2) measure is introduced and evaluated from a nursing practice standpoint. The RADS-2 is easy to use and demonstrates good reliability, validity, and construct features, providing evidence for nurses that the measure can be used with confidence in assessment of depressive symptoms in adolescents. The RADS-2 is an effective first-stage assessment of depressive mood in teens and preteens.

  5. Effect of the exchange-correlation potential and of surface relaxation on the description of the H2O dissociation on Cu(111)

    NASA Astrophysics Data System (ADS)

    Fajín, José L. C.; Illas, Francesc; Gomes, José R. B.

    2009-06-01

    The role of the exchange-correlation density functional (PBE, PW91, RevPBE) and of surface relaxation in the determination of the adsorption energies, reaction energy barriers, and reaction rate constants has been analyzed taking water dissociation on Cu(111) surface as a test case. The PBE and PW91 functionals yield similar adsorption geometries and, adsorption and activation energies, but differ significantly from RevPBE results. For each of the functionals tested, surface relaxation was found to have only a minor effect on the calculated (co)adsorption geometries and (co)adsorption energies. The calculated energy barriers for water dissociation are more affected by the functional used, especially in the case of the RevPBE, with obvious implications on the calculated energy barriers and derived reaction rate constants.

  6. Effect of internal noise on the oscillation of N{sub 2}O decomposition over Cu-ZSM-5 zeolites using a stochastic description

    SciTech Connect

    Liu, Fuliang; Li, Yaping Sun, Xiaoming

    2014-01-28

    When considering stochastic oscillations of heterogeneous catalyst systems, most researches have focused on the surface of a metal or its oxide catalysts, but there have been few studies on porous catalysts. In this work, the effects of internal noise on oscillations of N{sub 2}O decomposition over Cu-ZSM-5 zeolites are investigated, using the chemical Langevin equation and a mesoscopic stochastic model. Considering that Cu-ZSM-5 particles are finely divided particles, the number of Cu ions (N{sub s}) is proportional to the particle size at a certain Cu/Al, and the internal noise is inversely proportional to N{sub s}. Stochastic oscillations can be observed outside the deterministic oscillatory region. Furthermore, the performance of the oscillation characterized by the signal-to-noise ratio has a maximum within the optimal size range of 4–8 nm. This suggests that a nanometer-sized zeolite may be best for oscillations.

  7. Description of an experimental (hydrogen peroxide) rocket system and its use in measuring aileron and rudder effectiveness of a light airplane

    NASA Technical Reports Server (NTRS)

    Obryan, T. C.; Goode, M. W.; Gregory, F. D.; Mayo, M. H.

    1980-01-01

    A hydrogen peroxide fueled rocket system, which is to be used as a research tool in flight studies of stall and spin maneuvers, was installed on a light, four place general aviation airplane. The pilot controlled rocket system produces moments about either the roll or the yaw body axis to augment or oppose the aerodynamic forces and inertial moments acting on the airplane during various flight maneuvers, including the spin. These controlled moments of a known magnitude can be used in various ways to help analyze and interpret the importance of the various factors which influence airplane maneuvers. The rocket system and its installation in the airplane are described, and the results of flight rests used to measure rudder and aileron effectiveness at airspeeds above the stall are presented. These tests also serve to demonstrate the operational readiness of the rocket system for future research operations.

  8. Effectiveness of highway-drainage systems in preventing contamination of ground water by road salt, Route 25, southeastern Massachusetts; description of study area, data collection programs, and methodology

    USGS Publications Warehouse

    Church, P.E.; Armstrong, D.S.; Granato, G.E.; Stone, V.J.; Smith, K.P.; Provencher, P.L.

    1996-01-01

    Four test sites along a 7-mile section of Route 25 in southeastern Massachusetts, each representing a specific highway-drainage system, were instrumented to determine the effectiveness of the drainage systems in preventing contamination of ground water by road salt. One of the systems discharges highway runoff onsite through local drainpipes. The other systems use trunkline drainpipes through which runoff from highway surfaces, shoulders, and median strips is diverted and discharged into either a local stream or a coastal waterway. Route 25 was completed and opened to traffic in the summer of 1987. Road salt was first applied to the highway in the winter of 1987-88. The study area is on a thick outwash plain composed primarily of sand and gravel. Water-table depths range from 15 to 60 feet below land surface at the four test sites. Ground-water flow is in a general southerly direction, approximately perpendicular to the highway. Streamflow in the study area is controlled primarily by ground-water discharge. Background concentrations of dissolved chloride, sodium, and calcium-the primary constituents of road salt-are similar in ground water and surface water and range from 5 to 20, 5 to 10, and 1 to 5 milligrams per liter, respectively. Data-collection programs were developed for monitoring the application of road salt to the highway, the quantity of road-salt water entering the ground water, diverted through the highway-drainage systems, and entering a local stream. The Massachusetts Highway Department monitored road salt applied to the highway and reported these data to the U.S. Geological Survey. The U.S. Geological Survey designed and operated the ground-water, highway- drainage, and surface-water data-collection programs. A road-salt budget will be calculated for each test site so that the effectiveness of the different highway-drainage systems in preventing contamination of ground water by road salt can be determined.

  9. Description of self-reported fluid intake and its effects on body weight, symptoms, quality of life and physical capacity in patients with stable chronic heart failure.

    PubMed

    Holst, Marie; Strömberg, Anna; Lindholm, Maud; Willenheimer, Ronnie

    2008-09-01

    To describe the self-reported fluid intake and its effects on body weight, signs and symptoms of heart failure, quality of life, physical capacity and thirst, in patients with stabilised chronic heart failure. Patients with chronic heart failure are often recommended a fluid restriction of 1.5 l/day but there is no evidence in the literature for this recommendation and little is known about the fluid intake consequences. Crossover study. Chronic heart failure patients, clinically stabilised after an unstable state, were randomised to a 32-week cross-over study assessing the clinical importance of fluid prescription. In a secondary analysis of 63 patients, efficacy variables were analysed in relation to the self-reported median fluid intake of 19 ml/kg body weight/day. The mean fluid intake was 16 ml/kg/day in the below-median group and 24 ml/kg/day in the above-median group. No between-group differences were found in change in body weight, signs and symptoms, diuretic use, quality of life or physical capacity. However, the above-median group significantly decreased sense of thirst and difficulties to adhere to the fluid prescription compared with the below-median group. In clinically stabilised chronic heart failure patients on optimal pharmacological treatment, a larger fluid intake was associated with decreasing thirst without any measurable negative effects on signs and symptoms of heart failure, diuretic use or physical capacity. Thus, a more liberal fluid intake may be advisable in chronic heart failure patients who have been stabilised after an initial unstable clinical state. Nurses involved in the care for patients with heart failure known how troublesome thirst can be and how difficult it can be to follow a restricted fluid intake. This study indicates that it is possible to reassess and recommend a less strict fluid intake in stabilised patients with chronic heart failure.

  10. Prevalence and perceived health effect of alcohol use among male undergraduate students in Owerri, South-East Nigeria: a descriptive cross-sectional study

    PubMed Central

    2011-01-01

    Background Alcohol use during adolescence and young adulthood remains a prominent public health problem. Despite growing problems of global alcohol abuse, accurate information on the prevalence and pattern of use in Nigeria remain sparse. This study examines the prevalence and perceived health effects of alcohol use among undergraduate students in Owerri, Nigeria. Method The prevalence and perceived health effects of alcohol was estimated for 482 male undergraduates of four higher institutions in Owerri, South-East Nigeria between October 2008 and March 2009. Information was obtained using a semi-structured, self-administered questionnaire. Result The mean age of the students was 24.7 years. Majority of the respondents confirmed they were current users of alcohol given a prevalence of 78.4%, with twenty-seven percent of them being heavy drinkers (≥4 drinks per day). Reasons given by respondents for alcohol drinking include: makes them feel high (24.4%); makes them belong to the group of "most happening guys" on campus (6.6%); makes them feel relaxed (52.6%) while (16.4%) drinks it because their best friends do. Perceived health impacts of alcohol use among current users include: it enhances pleasure during moment of sex (51.1%), causes drowsiness and weakness (63.8%), may precipitate defective memory and impaired perception (64.3%) and serves as risk factor for most chronic diseases (68.5%). Conclusion High prevalence of alcohol use was established among study groups. Evaluation of full-scale community-level intervention, including community mobilisation and media advocacy aimed at supporting changes in policies on drinking, access and sales of alcohol to young people, could be helpful in reducing the trend. PMID:21333007

  11. Prevalence and perceived health effect of alcohol use among male undergraduate students in Owerri, South-East Nigeria: a descriptive cross-sectional study.

    PubMed

    Chikere, Ebirim I C; Mayowa, Morakinyo O

    2011-02-18

    Alcohol use during adolescence and young adulthood remains a prominent public health problem. Despite growing problems of global alcohol abuse, accurate information on the prevalence and pattern of use in Nigeria remain sparse. This study examines the prevalence and perceived health effects of alcohol use among undergraduate students in Owerri, Nigeria. The prevalence and perceived health effects of alcohol was estimated for 482 male undergraduates of four higher institutions in Owerri, South-East Nigeria between October 2008 and March 2009. Information was obtained using a semi-structured, self-administered questionnaire. The mean age of the students was 24.7 years. Majority of the respondents confirmed they were current users of alcohol given a prevalence of 78.4%, with twenty-seven percent of them being heavy drinkers (≥ 4 drinks per day). Reasons given by respondents for alcohol drinking include: makes them feel high (24.4%); makes them belong to the group of "most happening guys" on campus (6.6%); makes them feel relaxed (52.6%) while (16.4%) drinks it because their best friends do. Perceived health impacts of alcohol use among current users include: it enhances pleasure during moment of sex (51.1%), causes drowsiness and weakness (63.8%), may precipitate defective memory and impaired perception (64.3%) and serves as risk factor for most chronic diseases (68.5%). High prevalence of alcohol use was established among study groups. Evaluation of full-scale community-level intervention, including community mobilisation and media advocacy aimed at supporting changes in policies on drinking, access and sales of alcohol to young people, could be helpful in reducing the trend.

  12. Macroscopic Description for Networks of Spiking Neurons

    NASA Astrophysics Data System (ADS)

    Montbrió, Ernest; Pazó, Diego; Roxin, Alex

    2015-04-01

    A major goal of neuroscience, statistical physics, and nonlinear dynamics is to understand how brain function arises from the collective dynamics of networks of spiking neurons. This challenge has been chiefly addressed through large-scale numerical simulations. Alternatively, researchers have formulated mean-field theories to gain insight into macroscopic states of large neuronal networks in terms of the collective firing activity of the neurons, or the firing rate. However, these theories have not succeeded in establishing an exact correspondence between the firing rate of the network and the underlying microscopic state of the spiking neurons. This has largely constrained the range of applicability of such macroscopic descriptions, particularly when trying to describe neuronal synchronization. Here, we provide the derivation of a set of exact macroscopic equations for a network of spiking neurons. Our results reveal that the spike generation mechanism of individual neurons introduces an effective coupling between two biophysically relevant macroscopic quantities, the firing rate and the mean membrane potential, which together govern the evolution of the neuronal network. The resulting equations exactly describe all possible macroscopic dynamical states of the network, including states of synchronous spiking activity. Finally, we show that the firing-rate description is related, via a conformal map, to a low-dimensional description in terms of the Kuramoto order parameter, called Ott-Antonsen theory. We anticipate that our results will be an important tool in investigating how large networks of spiking neurons self-organize in time to process and encode information in the brain.

  13. Effects of errors in velocity tilt on maximum longitudinal compression during neutralized drift compression of intense beam pulses: I. general description

    SciTech Connect

    Kaganovich, Igor D.; Massidda, Scottt; Startsev, Edward A.; Davidson, Ronald C.; Vay, Jean-Luc; Friedman, Alex

    2012-06-21

    Neutralized drift compression offers an effective means for particle beam pulse compression and current amplification. In neutralized drift compression, a linear longitudinal velocity tilt (head-to-tail gradient) is applied to the non-relativistic beam pulse, so that the beam pulse compresses as it drifts in the focusing section. The beam current can increase by more than a factor of 100 in the longitudinal direction. We have performed an analytical study of how errors in the velocity tilt acquired by the beam in the induction bunching module limit the maximum longitudinal compression. It is found that the compression ratio is determined by the relative errors in the velocity tilt. That is, one-percent errors may limit the compression to a factor of one hundred. However, a part of the beam pulse where the errors are small may compress to much higher values, which are determined by the initial thermal spread of the beam pulse. It is also shown that sharp jumps in the compressed current density profile can be produced due to overlaying of different parts of the pulse near the focal plane. Examples of slowly varying and rapidly varying errors compared to the beam pulse duration are studied. For beam velocity errors given by a cubic function, the compression ratio can be described analytically. In this limit, a significant portion of the beam pulse is located in the broad wings of the pulse and is poorly compressed. The central part of the compressed pulse is determined by the thermal spread. The scaling law for maximum compression ratio is derived. In addition to a smooth variation in the velocity tilt, fast-changing errors during the pulse may appear in the induction bunching module if the voltage pulse is formed by several pulsed elements. Different parts of the pulse compress nearly simultaneously at the target and the compressed profile may have many peaks. The maximum compression is a function of both thermal spread and the velocity errors. The effects of the

  14. Effects of rapid eye movement sleep deprivation on the feeding behavior in the laboratory rat with a description of the cuff pedestal technique.

    PubMed

    Elomaa, E

    1985-01-01

    The cuff pedestal technique, with which it is possible to use the test animal as its own control both before and after REMs deprivation, was described. The validity of this modified procedure for REMs deprivation was tested with reference to the electrophysiological sleep correlates using 6 adult rats deprived of REMs for 3 days. The stress effects of the cuff pedestal treatment were assessed in terms of adrenal weights in 12 rats. The duration of REMs deprivation in this experiment was 5 days. The effects of REMs deprivation on locomotor activity and food intake were studied in 8 juvenile rats exposed to REMs deprivation by lowering the cuffs for 6 days after 3 baseline days with the cuffs raised. 24 h recordings of meal pattern data were obtained from 8 adult rats during one baseline day, during the first and sixth day of REMs deprivation and during the second day after termination of REMs deprivation. The main results were as follows: The procedure of placing experimentally naive rats on small pedestals surrounded by water inhibited normal food intake for several days. Concomitant weight losses were of the same order as have been reported to occur in control rats on large pedestals. This finding suggests that both the large and small pedestals should be equipped with movable cuffs and that actual deprivation should be started by lowering the cuffs only when the animals have exceeded their original weights. The electrophysiological sleep/waking cycle of rats adapted to living on the pedestal with the cuff raised was similar to that reported in rats under ordinary laboratory conditions. Lowering of the cuffs for 3 days resulted in an almost total disappearance of REMs. A prominent rebound increase of REMs occurred after raising of the cuffs. Rats kept for fourteen days on pedestals with the cuffs raised displayed an increase of about 20% in the weights of the adrenal bodies. A quite similar adrenal hypertrophy, however, also occurs in rats living under enriched

  15. Effect of animal-source food supplement prior to and during pregnancy on birthweight and prematurity in rural Vietnam: a brief study description.

    PubMed

    Tu, Ngu; King, Janet C; Dirren, Henri; Thu, Hoang Nga; Ngoc, Quyen Phi; Diep, Anh Nguyen Thi

    2014-12-01

    Maternal nutritional status is an important predictor of infant birthweight. Most previous attempts to improve birthweight through multiple micronutrient supplementation have been initiated after women are pregnant. Interventions to improve maternal nutritional status prior to conception may be more effective in preventing low birthweight and improving other infant health outcomes. To compare the effects of maternal supplementation with animal-source food from preconception to term or from mid-gestation to term with routine prenatal care on birthweight, the prevalence of preterm births, intrauterine growth restriction, and infant growth during the first 12 months of life and on maternal nutrient status and the incidence of maternal and infant infections. Young women from 29 rural communes in northwestern Vietnam were recruited when they registered to marry and were randomized to one of three interventions: animal-source food supplement 5 days per week from marriage to term (approximately 13 months), animal-source food supplement 5 days per week from 16 weeks of gestation to term (approximately 5 months), or routine prenatal care without supplementalfeeding. Data on infant birthweight and gestational age, maternal and infant anthropometry, micronutrient status, and infections in the infant and mother were collected at various time points. In a preliminary study of women of reproductive age in this area of Vietnam, 40% of the women were underweight (body mass index < 18.5) and anemic. About 50% had infections. Rice was the dietary staple, and nutrient-rich, animal-source foods were rarely consumed by women. Iron, zinc, vitamin A, folate, and vitamin B12 intakes were inadequate in about 40% of the women. The study is still ongoing, and further data are not yet available. The results of this study will provide important data regarding whether improved intake of micronutrient-rich animal-source foods that are locally available and affordable before and during pregnancy

  16. A generalized theoretical framework for the description of spin decoupling in solid-state MAS NMR: Offset effect on decoupling performance.

    PubMed

    Tan, Kong Ooi; Agarwal, Vipin; Meier, Beat H; Ernst, Matthias

    2016-09-07

    We present a generalized theoretical framework that allows the approximate but rapid analysis of residual couplings of arbitrary decoupling sequences in solid-state NMR under magic-angle spinning conditions. It is a generalization of the tri-modal Floquet analysis of TPPM decoupling [Scholz et al., J. Chem. Phys. 130, 114510 (2009)] where three characteristic frequencies are used to describe the pulse sequence. Such an approach can be used to describe arbitrary periodic decoupling sequences that differ only in the magnitude of the Fourier coefficients of the interaction-frame transformation. It allows a ∼100 times faster calculation of second-order residual couplings as a function of pulse sequence parameters than full spin-dynamics simulations. By comparing the theoretical calculations with full numerical simulations, we show the potential of the new approach to examine the performance of decoupling sequences. We exemplify the usefulness of this framework by analyzing the performance of commonly used high-power decoupling sequences and low-power decoupling sequences such as amplitude-modulated XiX (AM-XiX) and its super-cycled variant SC-AM-XiX. In addition, the effect of chemical-shift offset is examined for both high- and low-power decoupling sequences. The results show that the cross-terms between the dipolar couplings are the main contributions to the line broadening when offset is present. We also show that the SC-AM-XIX shows a better offset compensation.

  17. A descriptive study to provide evidence of the teratogenic and cellular effects of sibutramine and ephedrine on cardiac- and liver-tissue of chick embryos.

    PubMed

    Oberholzer, Hester Magdalena; Van Der Schoor, Ciska; Taute, Helena; Bester, Megan Jean

    2015-08-01

    Exposure to drugs during pregnancy is a major concern, as some teratogenic compounds can influence normal foetal development. Although the use of drugs during pregnancy should generally be avoided, exposure of the developing foetus to teratogens may occur unknowingly since these compounds may be hidden in products that are being marketed as "all natural." The aim of the current study was to investigate the possible teratogenic and cellular effects of sibutramine-a serotonin-norepinephrine reuptake inhibitor used in the treatment of obesity-on the heart and liver tissue of chick embryos. Ephedrine was used as a positive control. The chick embryo model was chosen because it has been used in studying developmental and experimental biology and teratology with great success. The embryos were exposed to three different concentrations of sibutramine and ephedrine respectively. The results obtained revealed that both compounds exhibited embryotoxicity when compared to the control groups. Liver and heart tissue of the exposed embryos was severely affected by these compounds in a dose-related manner. Morphology similar to that of muscle dystrophy was observed in the heart, where the muscle tissue was infiltrated by adipose and connective tissue. Severe liver steatosis was also noted. A more in-depth investigation into the molecular pathways involved might provide more information on the exact mechanism of toxicity of these products influencing embryonic development.

  18. Flight survey of the 757 wing noise field and its effects on laminar boundary layer transition. Volume 1: Program description and data analysis

    NASA Technical Reports Server (NTRS)

    1987-01-01

    It was previously observed that an incident acoustic field on a wing with laminar flow can cause transition to turbulent flow if the fluctuating acoustic velocities are of sufficient amplitude and in the critical frequency range for an unstable laminar boundary layer. A section of a wing was modified with a natural laminar flow (NLF) glove to allow direct measurement of the effect of varying engine noise on the extent of laminar flow. The flight test program was completed in June, 1985. At each flight condition, the engine power was varied from about 2600 r/min (idle) to about 4500 r/min (maximum continuous power). The spectral data provides considerable insight into the influences of the various sound sources that contribute to the overall noise levels. Additional analysis will be required to assess the impact of these sources on boundary layer transition. These results demonstrate that substantial laminar flow on the wing of a transport configuration with wing-mounted engines can be obtained.

  19. Aerosol indirect effect on the grid-scale clouds in the two-way coupled WRF–CMAQ: model description, development, evaluation and regional analysis

    SciTech Connect

    Yu, S.; Mathur, R.; Pleim, J.; Wong, D.; Gilliam, R.; Alapaty, K.; Zhao, C.; Liu, X.

    2014-01-01

    This study implemented first, second and glaciation aerosol indirect effects (AIE) on resolved clouds in the two-way coupled Weather Research and Forecasting Community Multiscale Air Quality (WRF–CMAQ) modeling system by including parameterizations for both cloud drop and ice number concentrations on the basis of CMAQ-predicted aerosol distributions and WRF meteorological conditions. The performance of the newly developed WRF–CMAQ model, with alternate Community Atmospheric Model (CAM) and Rapid Radiative Transfer Model for GCMs (RRTMG) radiation schemes, was evaluated with observations from the Clouds and the See http://ceres.larc.nasa.gov/. Earth's Radiant Energy System (CERES) satellite and surface monitoring networks (AQS, IMPROVE, CASTNET, STN, and PRISM) over the continental US (CONUS) (12 km resolution) and eastern Texas (4 km resolution) during August and September of 2006. The results at the Air Quality System (AQS) surface sites show that in August, the normalized mean bias (NMB) values for PM2.5 over the eastern US (EUS) and the western US (WUS) are 5.3% (-0.1%) and 0.4% (-5.2%) for WRF–CMAQ/CAM (WRF–CMAQ/RRTMG), respectively. The evaluation of PM2.5 chemical composition reveals that in August, WRF–CMAQ/CAM (WRF–CMAQ/RRTMG) consistently underestimated the observed SO42- by -23.0% (-27.7%), -12.5% (-18.9%) and -7.9% (-14.8%) over the EUS at the Clean Air Status Trends Network (CASTNET), Interagency Monitoring of Protected Visual Environments (IMPROVE) and Speciated Trends Network (STN) sites, respectively. Both configurations (WRF–CMAQ/CAM, WRF–CMAQ/RRTMG) overestimated the observed mean organic carbon (OC), elemental carbon (EC) and and total carbon (TC) concentrations over the EUS in August at the IMPROVE sites. Both configurations generally underestimated the cloud field (shortwave cloud forcing, SWCF) over the CONUS in August due to the

  20. Oligarchy as a phase transition: The effect of wealth-attained advantage in a Fokker-Planck description of asset exchange

    NASA Astrophysics Data System (ADS)

    Boghosian, Bruce M.; Devitt-Lee, Adrian; Johnson, Merek; Li, Jie; Marcq, Jeremy A.; Wang, Hongyan

    2017-06-01

    The ;Yard-Sale Model; of asset exchange is known to result in complete inequality-all of the wealth in the hands of a single agent. It is also known that, when this model is modified by introducing a simple model of redistribution based on the Ornstein-Uhlenbeck process, it admits a steady state exhibiting some features similar to the celebrated Pareto Law of wealth distribution. In the present work, we analyze the form of this steady-state distribution in much greater detail, using a combination of analytic and numerical techniques. We find that, while Pareto's Law is approximately valid for low redistribution, it gives way to something more similar to Gibrat's Law when redistribution is higher. Additionally, we prove in this work that, while this Pareto or Gibrat behavior may persist over many orders of magnitude, it ultimately gives way to gaussian decay at extremely large wealth. Also in this work, we introduce a bias in favor of the wealthier agent-what we call Wealth-Attained Advantage (WAA)-and show that this leads to the phenomenon of ;wealth condensation; when the bias exceeds a certain critical value. In the wealth-condensed state, a finite fraction of the total wealth of the population ;condenses; to the wealthiest agent. We examine this phenomenon in some detail, and derive the corresponding modification to the Fokker-Planck equation. We observe a second-order phase transition to a state of coexistence between an oligarch and a distribution of non-oligarchs. Finally, by studying the asymptotic behavior of the distribution in some detail, we show that the onset of wealth condensation has an abrupt reciprocal effect on the character of the non-oligarchical part of the distribution. Specifically, we show that the above-mentioned gaussian decay at extremely large wealth is valid both above and below criticality, but degenerates to exponential decay precisely at criticality.

  1. The effect of nitrogen doping on mercury oxidation/chemical adsorption on the CuCo2O4(110) surface: a molecular-level description.

    PubMed

    Mei, Zhijian; Fan, Maohong; Zhang, Ruiqing; Shen, Zhemin; Wang, Wenhua

    2014-07-14

    Based on density functional theory (DFT) calculations, the detailed mercury oxidation/chemical adsorption mechanisms on the N-doped CuCo2O4(110) surface are studied. The DFT calculations show that Ow (bonded with one Cu(2+) ion and one Co(3+) ion) is far more active than Os (bonded with three Co(3+) ions) and the mercury oxidation/chemical adsorption activation energy (Ea) on the virgin CuCo2O4(110) surface involving Ow is 0.85 eV. The physically adsorbed mercury overcomes the Ea and enters the energy well that plays an important role in mercury oxidation/chemical adsorption. Nitrogen doping can greatly increase the activity of Ow and decrease the activity of Os at the same time, which greatly affect the mercury oxidation/chemical adsorption abilities on the CuCo2O4(110) surface, and the Ea variation of mercury oxidation/chemical adsorption is as follows: 0.85 eV (virgin CuCo2O4(110)) → 0.76 eV (one N-doped CuCo2O4(110)) → 0.69 eV (two N-doped CuCo2O4(110)) → 0.48 eV (three N-doped CuCo2O4(110)). In addition, N-doping can decrease the adsorption energy of mercury and mercuric oxide. The effect of N-doping on the bonding mechanism of mercury adsorption on the CuCo2O4(110) surface is analyzed by the local density of state (LDOS) and the natural bonding orbital (NBO). The calculation results correspond well to the experimental data.

  2. Comparing probabilistic and descriptive analyses of time-dose-toxicity relationship for determining no-observed-adverse-effect level in drug development.

    PubMed

    Glatard, Anaïs; Berges, Aliénor; Sahota, Tarjinder; Ambery, Claire; Osborne, Jan; Smith, Randall; Hénin, Emilie; Chen, Chao

    2015-10-15

    The no-observed-adverse-effect level (NOAEL) of a drug defined from animal studies is important for inferring a maximal safe dose in human. However, several issues are associated with its concept, determination and application. It is confined to the actual doses used in the study; becomes lower with increasing sample size or dose levels; and reflects the risk level seen in the experiment rather than what may be relevant for human. We explored a pharmacometric approach in an attempt to address these issues. We first used simulation to examine the behaviour of the NOAEL values as determined by current common practice; and then fitted the probability of toxicity as a function of treatment duration and dose to data collected from all applicable toxicology studies of a test compound. Our investigation was in the context of an irreversible toxicity that is detected at the end of the study. Simulations illustrated NOAEL's dependency on experimental factors such as dose and sample size, as well as the underlying uncertainty. Modelling the probability as a continuous function of treatment duration and dose simultaneously to data from multiple studies allowed the estimation of the dose, along with its confidence interval, for a maximal risk level that might be deemed as acceptable for human. The model-based data integration also reconciled between-study inconsistency and explicitly provided maximised estimation confidence. Such alternative NOAEL determination method should be explored for its more efficient data use, more quantifiable insight to toxic doses, and the potential for more relevant animal-to-human translation.

  3. Long-Term Metabolic Effects in French-Canadian Children and Adolescents Treated with Second-Generation Antipsychotics in Monotherapy or Polytherapy: A 24-Month Descriptive Retrospective Study.

    PubMed

    Ilies, Drigissa; Huet, Anne-Sophie; Lacourse, Eric; Roy, Geneviève; Stip, Emmanuel; Amor, Leila Ben

    2017-01-01

    To compare weight and glucose changes of long-term second-generation antipsychotic (SGA) monotherapy versus polytherapy (switching or combining SGAs) in children and adolescents. This is a 24-month retrospective study conducted between November 2005 and June 2013. From 147 antipsychotic-naive patients selected (mean age, 12.8 years; 95% confidence interval [CI], 9.8-15.9), 116 (78.9%) received SGA monotherapy and 31 (21.1%) SGA polytherapy for up to 24 months. Height, weight, and fasting glucose (FG) were measured at baseline and 1, 3, 6, 12, and 24 months. Linear mixed-model analysis was used to compare weight, body mass index z score (BMI z score), and glucose changes between the 2 SGA treatment groups, with the repeated factor being the time relative to baseline at 1, 3, 6, 12, and 24 months. Overall, after 24 months of SGA treatment, mean weight increased significantly by 12.8 kg (95% CI, 10.4-15.0), BMI z score by 0.44 (95% CI, 0.21-0.68), and FG levels by 0.29 mmol/L (95% CI, 0.11-0.47). Incidence of overweight/obesity was 22.6%, BMI z score increase over 0.5 was 9.4%, impaired fasting glucose was 9.4%, and type 2 diabetes mellitus was 3.1%. Regarding metabolic effects, no significant difference was found between the subjects taking a single SGA and those exposed to an SGA polytherapy. Our study confirms the significant increase of metabolic complications during 24 months of SGA treatment without excluding or confirming a difference between the 2 groups of treatment (mono vs. poly).

  4. Effects of music intervention on anxiety and pain reduction in ambulatory maxillofacial and otorhinolaryngology surgery: a descriptive survey of 27 cases.

    PubMed

    Keilani, Chafik; Simondet, Nicolas; Maalouf, Ramzi; Yigitoglu, Ahmet; Bougrine, Alexandre; Simon, Didier; Fligny, Isabelle

    2017-06-01

    The aim of this study is to determine patients' opinion regarding listening to music before an ambulatory maxillofacial surgery and effects on anxiety and pain reduction. This study was conducted on outpatients having a maxillofacial surgery between December 2015 and April 2016 at Poissy/Saint-Germain-en-Laye hospital (France). Patients listened with headphones to an easy-listening music in the operation theater before the first ambulation. A questionnaire including a visual analog scale (VAS) for pain and anxiety was given to participants. The primary endpoint was to determine patients' opinion regarding listening to music before surgery. Secondary endpoints were to determine VAS pain mean, VAS anxiety mean before surgery, VAS anxiety mean after surgery, and if patients wanted to listen to their own playlist. We decided to compare VAS anxiety and pain mean between patients who accepted to listen to music (ALM) and who refused to listen to music (RLM). Nineteen patients ALM and 8 patients RLM to music. 78.9% of patients considered that listening to music before surgery decreased their anxiety. In patients who ALM, the mean (standard deviation, SD) of VAS pain after surgery was 3.42 (1.95), the mean (SD) of VAS anxiety before surgery was 3.1 (2.3), and the mean (SD) of VAS anxiety was 1.21 (0.85). There was a statistically significantly difference of the VAS anxiety mean (SD) before surgery between patients who ALM 3.10 (2.30) and who RLM 6.12 (1.88) (p = 0.005). There was a statistically significantly difference of the VAS anxiety mean (SD) after surgery between patients who ALM 1.21 (0.85) and who RLM 2.62 (1.30) (p = 0.009). Fifty percent of the patients wanted to choose their own music. Music seems to reduce anxiety before maxillofacial surgery. An interventional randomized study is needed to demonstrate the positive impact of music on anxiety before maxillofacial surgery.

  5. Description and design considerations of a randomized clinical trial investigating the effect of a multidisciplinary cognitive-behavioural intervention for patients undergoing lumbar spinal fusion surgery

    PubMed Central

    2014-01-01

    Background The ideal rehabilitation strategy following lumbar spinal fusion surgery has not yet been established. This paper is a study protocol, describing the rationale behind and the details of a cognitive-behavioural rehabilitation intervention for lumbar spinal fusion patients based on the best available evidence. Predictors of poor outcome following spine surgery have been identified to provide targets for the intervention, and the components of the intervention were structured in accordance with the cognitive-behavioural model. The study aims to compare the clinical and economical effectiveness of a cognitive-behavioural rehabilitation strategy to that of usual care for patients undergoing lumbar spinal fusion surgery. Methods/Design The study is a randomized clinical trial including 96 patients scheduled for lumbar spinal fusion surgery due to degenerative disease or spondylolisthesis. Patients were recruited in the period October 2011 to July 2013, and the follow-up period is one year from date of surgery. Patients are allocated on a 1:2 ratio (control: intervention) to either treatment as usual (control group), which implies surgery and the standard postoperative rehabilitation, or in addition to this, a patient education focusing on pain behaviour and pain coping (intervention group). It takes place in a hospital setting, and consists of six group-based sessions, managed by a multidisciplinary team of health professionals. The primary outcomes are disability (Oswestry Disability Index) and sick leave, while secondary outcomes include coping (Coping Strategies Questionnaire), fear-avoidance belief (Fear Avoidance Belief Questionnaire), pain (Low Back Pain Rating Scale, pain index), mobility during hospitalization (Cumulated Ambulation Score), generic health-related quality of life (EQ-5D) and resource use. Outcomes are measured using self report questionnaires, medical records and national registers. Discussion It is expected that the intervention can

  6. Spacelab Mission 3 experiment descriptions

    NASA Technical Reports Server (NTRS)

    Hill, C. K. (Editor)

    1982-01-01

    The Spacelab 3 mission is the first operational flight of Spacelab aboard the shuttle transportation system. The primary objectives of this mission are to conduct application, science, and technology experimentation that requires the low gravity environment of Earth orbit and an extended duration, stable vehicle attitude with emphasis on materials processing. This document provides descriptions of the experiments to be performed during the Spacelab 3 mission.

  7. Solar mesosphere explorer: Experiment description

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The Solar Mesosphere Explorer (SME) satellite experiments will provide a comprehensive study of atmospheric ozone and the processes which form and destroy it. Five instruments to be carried on the spacecraft will measure the ozone density and altitude distribution, monitor the incoming solar radiation, and measure other atmospheric constituents which affect ozone. The investigative approach concept, methods and procedures, preflight studies, and orbits and mission lifetime are presented. Descriptions of the instruments are also presented.

  8. Continuum description for jointed media

    SciTech Connect

    Thomas, R.K.

    1982-04-01

    A general three-dimensional continuum description is presented for a material containing regularly spaced and approximately parallel jointing planes within a representative elementary volume. Constitutive relationships are introduced for linear behavior of the base material and nonlinear normal and shear behavior across jointing planes. Furthermore, a fracture permeability tensor is calculated so that deformation induced alterations to the in-situ values can be measured. Examples for several strain-controlled loading paths are presented.

  9. Closed terminologies in description logics

    SciTech Connect

    Weida, R.A. |

    1996-12-31

    We introduce a predictive concept recognition methodology for description logics based on a new closed terminology assumption. During knowledge engineering, our system adopts the standard open terminology assumption as it automatically classifies concept descriptions into a taxonomy via subsumption inferences. However, for applications like configuration, the terminology becomes fixed during problem solving. Then, closed terminology reasoning is more appropriate. In our interactive configuration application, a user incrementally specifies an individual computer system in collaboration with a configuration engine. Choices can be made in any order and at any level of abstraction. We distinguish between abstract and concrete concepts to formally define when an individual`s description may be considered finished. We also take advantage of the closed terminology assumption, together with the terminology`s subsumption-based organization, to efficiently track the types of systems and components consistent with current choices, infer additional constraints on current choices, and appropriately guide future choices. Thus, we can help focus the efforts of both user and configuration engine.

  10. Description of the Wharton/ODA System.

    DTIC Science & Technology

    1979-12-01

    A D-AA079 601 WHARTON SCHOOL PHILADELPHIA PA DEPT OF DECISION SCIENCIES F/B 5/2 DESCRIPTION OF THE WHARTON/ODA SYSTEM.(U) DEC 79 D OPPENHEIM. J S...management will be the development of a general strategy for the linking of human decision maker, computer decision aid, and the various kinds of...terminal devices so as to maximize human effectiveness. In addition, higher level or "macro" calls will be implemented for the graphics library, and

  11. Shell model description of zirconium isotopes

    SciTech Connect

    Sieja, K.; Nowacki, F.; Langanke, K.; Martinez-Pinedo, G.

    2009-06-15

    We calculate the low-lying spectra and several high-spin states of zirconium isotopes (Z=40) with neutron numbers from N=50 to N=58 using a large valence space with the {sup 78}Ni inert core, which a priori allows one to study the interplay between spherical and deformed configurations, necessary for the description of nuclides in this part of the nuclear chart. The effective interaction is derived by monopole corrections of the realistic G matrix. We reproduce essential nuclear properties, such as subshell closures in {sup 96}Zr and {sup 98}Zr. The spherical-to-deformed shape transition in {sup 100}Zr is addressed as well.

  12. Theoretical Description of the Fission Process

    SciTech Connect

    Witold Nazarewicz

    2003-07-01

    The main goals of the project can be summarized as follows: Development of effective energy functionals that are appropriate for the description of heavy nuclei. Our goal is to improve the existing energy density (Skyrme) functionals to develop a force that will be used in calculations of fission dynamics. Systematic self-consistent calculations of binding energies and fission barriers of actinide and trans-actinide nuclei using modern density functionals. This will be followed by calculations of spontaneous fission lifetimes and mass and charge divisions using dynamic adiabatic approaches based on the WKB approximation. Investigate novel microscopic (non-adiabatic) methods to study the fission process.

  13. Horizons of description: Black holes and complementarity

    NASA Astrophysics Data System (ADS)

    Bokulich, Peter Joshua Martin

    dissertation is that we have as much to learn from the limitations facing our scientific descriptions as we do from the successes they enjoy. Because all of our scientific theories offer at best limited, effective accounts of the world, an important part of our interpretive efforts will be assessing the borders of these domains of description.

  14. Generating Effective Tutorial Descriptions That Use Examples

    DTIC Science & Technology

    1992-01-01

    References [1] Jerome S . Bruner . Toward a Theory of Instruction. Oxford University Press, London, U.K, 1966. [21 Douglas W. Carnine. Two Letter...the example and the text? The text and the example( s ) should use the same lexical items to refer to the same concepts. 9. We already know from work... educational literature [5]. Consider once again, the examples in Figure 1: tags such as "List of Symbols’ and "List of combined Symbols and Numbers

  15. Perception of late effects among long-term survivors after haematopoietic stem cell transplantation: Descriptive analysis and validation of the Brief Illness Perception Questionnaire. A sub-study of the PROVIVO study.

    PubMed

    Valenta, Sabine; De Geest, Sabina; Fierz, Katharina; Beckmann, Sonja; Halter, Jörg; Schanz, Urs; Nair, Gayathri; Kirsch, Monika

    2017-04-01

    To give a first description of the perception of late effects among long-term survivors after Allogeneic Haematopoietic Stem Cell Transplantation (HSCT) and to validate the German Brief Illness Perception Questionnaire (BIPQ). This is a secondary analysis of data from the cross-sectional, mixed-method PROVIVO study, which included 376 survivors from two Swiss HSCT-centres. First, we analysed the sample characteristics and the distribution for each BIPQ item. Secondly, we tested three validity types following the American Educational Research Association (AERA)Standards: content validity indices (CVIs) were assessed based on an expert survey (n = 9). A confirmatory factor analysis (CFA) explored the internal structure, and correlations tested the validity in relations to other variables including data from the Hospital Anxiety and Depression Scale (HADS), the number and burden of late effects and clinical variables. In total, 319 HSCT recipients returned completed BIPQs. For this sample, the most feared threat for post-transplant life was long lasting late effects (median = 8/10). The expert-survey revealed an overall acceptable CVI (0.82), three items-on personal control, treatment control and causal representation-yielded low CVIs (<.78). The CFA confirmed that the BIPQ fits the underlying construct, the Common-Sense Model (CSM) (χ(2) (df) = 956.321, p = 0.00). The HADS-scores correlated strongly with the item emotional representation (r = 0.648; r = 0.656). According to its overall content validity, the German BIPQ is a promising instrument to gain deeper insights into patients' perceptions of HSCT late effects. However, as three items revealed potential problems, improvements and adaptions in translation are therefore required. Following these revisions, validity evidence should be re-examined through an in-depth patient survey. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Compact and Hybrid Feature Description for Building Extraction

    NASA Astrophysics Data System (ADS)

    Li, Z.; Liu, Y.; Hu, Y.; Li, P.; Ding, Y.

    2017-05-01

    Building extraction in aerial orthophotos is crucial for various applications. Currently, deep learning has been shown to be successful in addressing building extraction with high accuracy and high robustness. However, quite a large number of samples is required in training a classifier when using deep learning model. In order to realize accurate and semi-interactive labelling, the performance of feature description is crucial, as it has significant effect on the accuracy of classification. In this paper, we bring forward a compact and hybrid feature description method, in order to guarantees desirable classification accuracy of the corners on the building roof contours. The proposed descriptor is a hybrid description of an image patch constructed from 4 sets of binary intensity tests. Experiments show that benefiting from binary description and making full use of color channels, this descriptor is not only computationally frugal, but also accurate than SURF for building extraction.

  17. Standardizing the microsystems technology description

    NASA Astrophysics Data System (ADS)

    Liateni, Karim; Thomas, Gabriel; Hui Bon Hoa, Christophe; Bensaude, David

    2002-04-01

    The microsystems industry is promising a rapid and widespread growth for the coming years. The automotive, network, telecom and electronics industries take advantage of this technology by including it in their products; thus, getting better integration and high energetic performances. Microsystems related software and data exchange have inherited from the IC technology experience or standards, which appear not to fit the advanced level of conception currently needed by microsystems designers. A typical design flow to validate a microsystem device involves several software from disconnected areas like layout editors, FEM simulators, HDL modeling and simulation tools. However, and fabricated microsystem is obtained through execution of a layered process. Process characteristics will be used at each level of the design and analysis. Basically, the designer will have to customize each of his tools after the process. The project introduced here intends to unify the process description language and speed up the critical and tedious CAD customization task. We gather all the information related to the technology of a microsystem process in a single file. It is based on the XML standard format to receive worldwide attention. This format is called XML-MTD, standing for XML Microsystems Technology Description. Built around XML, it is an ASCII format which gives the ability to handle a comprehensive database for technology data. This format is open, given under general public license, but the aim is to manage the format withing a XML-MTD consortium of leader and well-established EDA companies and Foundries. In this way, it will take profit of their experience. For automated configuration of design and analysis tools regarding process-dependant information, we ship the Technology Manger software. Technology Manager links foundries with a large panel of standard EDA and FEA packages used by design teams relying on the Microsystems Technology Description in XML-MTD format.

  18. SNF AGING SYSTEM DESCRIPTION DOCUMENT

    SciTech Connect

    L.L. Swanson

    2005-04-06

    The purpose of this system description document (SDD) is to establish requirements that drive the design of the spent nuclear fuel (SNF) aging system and associated bases, which will allow the design effort to proceed. This SDD will be revised at strategic points as the design matures. This SDD identifies the requirements and describes the system design, as it currently exists, with emphasis on attributes of the design provided to meet the requirements. This SDD is an engineering tool for design control; accordingly, the primary audience and users are design engineers. This SDD is part of an iterative design process. It leads the design process with regard to the flow down of upper tier requirements onto the system. Knowledge of these requirements is essential in performing the design process. The SDD follows the design with regard to the description of the system. The description provided in the SDD reflects the current results of the design process. Throughout this SDD, the term aging cask applies to vertical site-specific casks and to horizontal aging modules. The term overpack is a vertical site-specific cask that contains a dual-purpose canister (DPC) or a disposable canister. Functional and operational requirements applicable to this system were obtained from ''Project Functional and Operational Requirements'' (F&OR) (Curry 2004 [DIRS 170557]). Other requirements that support the design process were taken from documents such as ''Project Design Criteria Document'' (PDC) (BSC 2004 [DES 171599]), ''Site Fire Hazards Analyses'' (BSC 2005 [DIRS 172174]), and ''Nuclear Safety Design Bases for License Application'' (BSC 2005 [DIRS 171512]). The documents address requirements in the ''Project Requirements Document'' (PRD) (Canori and Leitner 2003 [DIRS 166275]). This SDD includes several appendices. Appendix A is a Glossary; Appendix B is a list of key system charts, diagrams, drawings, lists and additional supporting information; and Appendix C is a list of

  19. The MUNU experiment, general description

    NASA Astrophysics Data System (ADS)

    Amsler, C.; Avenier, M.; Bagieu, G.; Barnoux, C.; Becker, H.-W.; Brissot, R.; Broggini, C.; Busto, J.; Cavaignac, J.-F.; Farine, J.; Filippi, D.; Gervasio, G.; Giarritta, P.; Grgić, G.; Guerre Chaley, B.; Joergens, V.; Koang, D. H.; Lebrun, D.; Luescher, R.; Mattioli, F.; Negrello, M.; Ould-Saada, F.; Paić, A.; Piovan, O.; Puglierin, G.; Schenker, D.; Stutz, A.; Tadsen, A.; Treichel, M.; Vuilleumier, J.-L.; Vuilleumier, J.-M.; MUNU Collaboration

    1997-02-01

    We are building a low background detector based on a gas time projection chamber surrounded by an active anti-Compton shielding. The detector will be installed near a nuclear reactor in Bugey for the experimental study of overlineνee- scattering. We give here a general description of the experiment, and an estimate of the expected counting rate and background. The construction of the time projection chamber is described in details. Results of first test measurements concerning the attenuation length and the spatial as well as energy resolution in the CF 4 fill gas are reported.

  20. Descriptive Model of Generic WAMS

    SciTech Connect

    Hauer, John F.; DeSteese, John G.

    2007-06-01

    The Department of Energy’s (DOE) Transmission Reliability Program is supporting the research, deployment, and demonstration of various wide area measurement system (WAMS) technologies to enhance the reliability of the Nation’s electrical power grid. Pacific Northwest National Laboratory (PNNL) was tasked by the DOE National SCADA Test Bed Program to conduct a study of WAMS security. This report represents achievement of the milestone to develop a generic WAMS model description that will provide a basis for the security analysis planned in the next phase of this study.

  1. "Influence Method". Detailed mathematical description

    NASA Astrophysics Data System (ADS)

    Rios, I. J.; Mayer, R. E.

    2015-07-01

    A new method for the absolute determination of nuclear particle flux in the absence of known detector efficiency, the "Influence Method", was recently published (I.J. Rios and R.E. Mayer, Nuclear Instruments & Methods in Physics Research A 775 (2015) 99-104). The method defines an estimator for the population and another estimator for the efficiency. In this article we present a detailed mathematical description which yields the conditions for its application, the probability distributions of the estimators and their characteristic parameters. An analysis of the different cases leads to expressions of the estimators and their uncertainties.

  2. Hadl: HUMS Architectural Description Language

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.; Adavi, V.; Agarwal, N.; Gullapalli, S.; Kumar, P.; Sundaram, P.

    2004-01-01

    Specification of architectures is an important prerequisite for evaluation of architectures. With the increase m the growth of health usage and monitoring systems (HUMS) in commercial and military domains, the need far the design and evaluation of HUMS architectures has also been on the increase. In this paper, we describe HADL, HUMS Architectural Description Language, that we have designed for this purpose. In particular, we describe the features of the language, illustrate them with examples, and show how we use it in designing domain-specific HUMS architectures. A companion paper contains details on our design methodology of HUMS architectures.

  3. IUE/IRA system description

    NASA Technical Reports Server (NTRS)

    Jennings, J.

    1977-01-01

    The IUE/IRA rate sensor system designed to meet the requirements of the International Ultraviolet Explorer spacecraft mission is described. The system consists of the sensor unit containing six rate sensor modules and the electronic control unit containing the rate sensor support electronics and the command/control circuitry. The inertial reference assembly formed by the combined units will provide spacecraft rate information for use in the stabilization and control system. The system is described in terms of functional description, operation redundancy performance, mechanical interface, and electrical interface. Test data obtained from the flight unit are summarized.

  4. Orbiter active thermal control system description

    NASA Technical Reports Server (NTRS)

    Laubach, G. E.

    1975-01-01

    A brief description of the Orbiter Active Thermal Control System (ATCS) including (1) major functional requirements of heat load, temperature control and heat sink utilization, (2) the overall system arrangement, and (3) detailed description of the elements of the ATCS.

  5. Orbiter active thermal control system description

    NASA Technical Reports Server (NTRS)

    Laubach, G. E.

    1975-01-01

    A brief description of the Orbiter Active Thermal Control System (ATCS) including (1) major functional requirements of heat load, temperature control and heat sink utilization, (2) the overall system arrangement, and (3) detailed description of the elements of the ATCS.

  6. Chemical effects in biological systems--data dictionary (CEBS-DD): a compendium of terms for the capture and integration of biological study design description, conventional phenotypes, and 'omics data.

    PubMed

    Fostel, Jennifer; Choi, Danielle; Zwickl, Craig; Morrison, Norman; Rashid, Asif; Hasan, Atif; Bao, Wenjun; Richard, Ann; Tong, Weida; Bushel, Pierre R; Brown, Roger; Bruno, Maribel; Cunningham, Michael L; Dix, David; Eastin, William; Frade, Carlos; Garcia, Alex; Heinloth, Alexandra; Irwin, Rick; Madenspacher, Jennifer; Merrick, B Alex; Papoian, Thomas; Paules, Richard; Rocca-Serra, Philippe; Sansone, Assunta-Susanna; Stevens, James; Tomer, Kenneth; Yang, Chihae; Waters, Michael

    2005-12-01

    A critical component in the design of the Chemical Effects in Biological Systems (CEBS) Knowledgebase is a strategy to capture toxicogenomics study protocols and the toxicity endpoint data (clinical pathology and histopathology). A Study is generally an experiment carried out during a period of time for the purpose of obtaining data, and the Study Design Description captures the methods, timing, and organization of the Study. The CEBS Data Dictionary (CEBS-DD) has been designed to define and organize terms in an attempt to standardize nomenclature needed to describe a toxicogenomics Study in a structured yet intuitive format and provide a flexible means to describe a Study as conceptualized by the investigator. The CEBS-DD will organize and annotate information from a variety of sources, thereby facilitating the capture and display of toxicogenomics data in biological context in CEBS, i.e., associating molecular events detected in highly-parallel data with the toxicology/pathology phenotype as observed in the individual Study Subjects and linked to the experimental treatments. The CEBS-DD has been developed with a focus on acute toxicity studies, but with a design that will permit it to be extended to other areas of toxicology and biology with the addition of domain-specific terms. To illustrate the utility of the CEBS-DD, we present an example of integrating data from two proteomics and transcriptomics studies of the response to acute acetaminophen toxicity (A. N. Heinloth et al., 2004, Toxicol. Sci. 80, 193-202).

  7. Model Experiments and Model Descriptions

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Ko, Malcolm K. W.; Weisenstein, Debra; Scott, Courtney J.; Shia, Run-Lie; Rodriguez, Jose; Sze, N. D.; Vohralik, Peter; Randeniya, Lakshman; Plumb, Ian

    1999-01-01

    The Second Workshop on Stratospheric Models and Measurements Workshop (M&M II) is the continuation of the effort previously started in the first Workshop (M&M I, Prather and Remsberg [1993]) held in 1992. As originally stated, the aim of M&M is to provide a foundation for establishing the credibility of stratospheric models used in environmental assessments of the ozone response to chlorofluorocarbons, aircraft emissions, and other climate-chemistry interactions. To accomplish this, a set of measurements of the present day atmosphere was selected. The intent was that successful simulations of the set of measurements should become the prerequisite for the acceptance of these models as having a reliable prediction for future ozone behavior. This section is divided into two: model experiment and model descriptions. In the model experiment, participant were given the charge to design a number of experiments that would use observations to test whether models are using the correct mechanisms to simulate the distributions of ozone and other trace gases in the atmosphere. The purpose is closely tied to the needs to reduce the uncertainties in the model predicted responses of stratospheric ozone to perturbations. The specifications for the experiments were sent out to the modeling community in June 1997. Twenty eight modeling groups responded to the requests for input. The first part of this section discusses the different modeling group, along with the experiments performed. Part two of this section, gives brief descriptions of each model as provided by the individual modeling groups.

  8. Model Experiments and Model Descriptions

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Ko, Malcolm K. W.; Weisenstein, Debra; Scott, Courtney J.; Shia, Run-Lie; Rodriguez, Jose; Sze, N. D.; Vohralik, Peter; Randeniya, Lakshman; Plumb, Ian

    1999-01-01

    The Second Workshop on Stratospheric Models and Measurements Workshop (M&M II) is the continuation of the effort previously started in the first Workshop (M&M I, Prather and Remsberg [1993]) held in 1992. As originally stated, the aim of M&M is to provide a foundation for establishing the credibility of stratospheric models used in environmental assessments of the ozone response to chlorofluorocarbons, aircraft emissions, and other climate-chemistry interactions. To accomplish this, a set of measurements of the present day atmosphere was selected. The intent was that successful simulations of the set of measurements should become the prerequisite for the acceptance of these models as having a reliable prediction for future ozone behavior. This section is divided into two: model experiment and model descriptions. In the model experiment, participant were given the charge to design a number of experiments that would use observations to test whether models are using the correct mechanisms to simulate the distributions of ozone and other trace gases in the atmosphere. The purpose is closely tied to the needs to reduce the uncertainties in the model predicted responses of stratospheric ozone to perturbations. The specifications for the experiments were sent out to the modeling community in June 1997. Twenty eight modeling groups responded to the requests for input. The first part of this section discusses the different modeling group, along with the experiments performed. Part two of this section, gives brief descriptions of each model as provided by the individual modeling groups.

  9. 7 CFR 52.1001 - Product description.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Product description. 52.1001 Section 52.1001... PROCESSED FOOD PRODUCTS 1 United States Standards for Grades of Dates Product Description, Styles, and Grades § 52.1001 Product description. Dates are the properly cured fresh fruit of the date tree (Phoenix...

  10. Pathways to Provenance: "DACS" and Creator Descriptions

    ERIC Educational Resources Information Center

    Weimer, Larry

    2007-01-01

    "Describing Archives: A Content Standard" breaks important ground for American archivists in its distinction between creator descriptions and archival material descriptions. Implementations of creator descriptions, many using Encoded Archival Context (EAC), are found internationally. "DACS"'s optional approach of describing…

  11. Staged description of the Finkelstein test.

    PubMed

    Dawson, Courtney; Mudgal, Chaitanya S

    2010-09-01

    We have revisited the original description of the Finkelstein test and review the reasons for its subsequent erroneous description. We have also outlined a staged description of this test, which we have found to be reliable and minimally painful for the diagnosis of de Quervain's tendonitis within our clinical practice.

  12. Atypical quantum confinement effect in silicon nanowires.

    PubMed

    Sorokin, Pavel B; Avramov, Pavel V; Chernozatonskii, Leonid A; Fedorov, Dmitri G; Ovchinnikov, Sergey G

    2008-10-09

    The quantum confinement effect (QCE) of linear junctions of silicon icosahedral quantum dots (IQD) and pentagonal nanowires (PNW) was studied using DFT and semiempirical AM1 methods. The formation of complex IQD/PNW structures leads to the localization of the HOMO and LUMO on different parts of the system and to a pronounced blue shift of the band gap; the typical QCE with a monotonic decrease of the band gap upon the system size breaks down. A simple one-electron one-dimensional Schrodinger equation model is proposed for the description and explanation of the unconventional quantum confinement behavior of silicon IQD/PNW systems. On the basis of the theoretical models, the experimentally discovered deviations from the typical QCE for nanocrystalline silicon are explained.

  13. Semiclassical description of autocorrelations in nuclear masses

    SciTech Connect

    Garcia-Garcia, Antonio M.; Hirsch, Jorge G.; Frank, Alejandro

    2006-08-15

    Nuclear mass autocorrelations are investigated as a function of the number of nucleons. The fluctuating part of these autocorrelations is modeled by a parameter free model in which the nucleons are confined in a rigid sphere. Explicit results are obtained by using periodic orbit theory. Despite the simplicity of the model we have found a remarkable quantitative agreement of the mass autocorrelations for all nuclei in the nuclear data chart. In order to achieve a similar degree of agreement for the nuclear masses themselves it is necessary to consider additional variables such as multipolar corrections to the spherical shape and an effective number of nucleons. Our findings suggest that higher order effects like nuclear deformations or residual interactions have little relevance in the description of the fluctuations of the nuclear autocorrelations.

  14. Towards a theoretical description of dense QCD

    NASA Astrophysics Data System (ADS)

    Philipsen, Owe

    2017-03-01

    The properties of matter at finite baryon densities play an important role for the astrophysics of compact stars as well as for heavy ion collisions or the description of nuclear matter. Because of the sign problem of the quark determinant, lattice QCD cannot be simulated by standard Monte Carlo at finite baryon densities. I review alternative attempts to treat dense QCD with an effective lattice theory derived by analytic strong coupling and hopping expansions, which close to the continuum is valid for heavy quarks only, but shows all qualitative features of nuclear physics emerging from QCD. In particular, the nuclear liquid gas transition and an equation of state for baryons can be calculated directly from QCD. A second effective theory based on strong coupling methods permits studies of the phase diagram in the chiral limit on coarse lattices.

  15. Mathematical Description of Bacterial Traveling Pulses

    PubMed Central

    Bournaveas, Nikolaos; Buguin, Axel; Silberzan, Pascal; Perthame, Benoît

    2010-01-01

    The Keller-Segel system has been widely proposed as a model for bacterial waves driven by chemotactic processes. Current experiments on Escherichia coli have shown the precise structure of traveling pulses. We present here an alternative mathematical description of traveling pulses at the macroscopic scale. This modeling task is complemented with numerical simulations in accordance with the experimental observations. Our model is derived from an accurate kinetic description of the mesoscopic run-and-tumble process performed by bacteria. This can account for recent experimental observations with E. coli. Qualitative agreements include the asymmetry of the pulse and transition in the collective behaviour (clustered motion versus dispersion). In addition, we can capture quantitatively the traveling speed of the pulse as well as its characteristic length. This work opens several experimental and theoretical perspectives since coefficients at the macroscopic level are derived from considerations at the cellular scale. For instance, the particular response of a single cell to chemical cues turns out to have a strong effect on collective motion. Furthermore, the bottom-up scaling allows us to perform preliminary mathematical analysis and write efficient numerical schemes. This model is intended as a predictive tool for the investigation of bacterial collective motion. PMID:20808878

  16. FLOWTRAN-TF code description

    SciTech Connect

    Flach, G.P.

    1990-12-01

    FLOWTRAN-TF is a two-component (air-water), two-phase thermal-hydraulics code designed for performing accident analyses of SRS reactor fuel assemblies during the Emergency Cooling System (ECS) phase of a Double Ended Guillotine Break (DEGB) Loss of Coolant Accident (LOCA). This report provides a brief description of the physical models in the version of FLOWTRAN-TF used to compute the Recommended K-Reactor Restart ECS Power Limit. This document is viewed as an interim report and should ultimately be superseded by a comprehensive user/programmer manual. In general, only high level discussions of governing equations and constitutive laws are presented. Numerical implementation of these models, code architecture and user information are not generally covered. A companion document describing code benchmarking is available.

  17. FLOWTRAN-TF code description

    SciTech Connect

    Flach, G.P.

    1991-09-01

    FLOWTRAN-TF is a two-component (air-water), two-phase thermal-hydraulics code designed for performing accident analyses of SRS reactor fuel assemblies during the Emergency Cooling System (ECS) phase of a Double Ended Guillotine Break (DEGB) Loss of Coolant Accident (LOCA). This report provides a brief description of the physical models in the version of FLOWTRAN-TF used to compute the Recommended K-Reactor Restart ECS Power Limit. This document is viewed as an interim report and should ultimately be superseded by a comprehensive user/programmer manual. In general, only high level discussions of governing equations and constitutive laws are presented. Numerical implementation of these models, code architecture and user information are not generally covered. A companion document describing code benchmarking is available.

  18. Elastin: molecular description and function.

    PubMed

    Debelle, L; Tamburro, A M

    1999-02-01

    Elastin, the protein responsible for the elastic properties of vertebrate tissues, has been thought to be solely restricted to that role. As a consequence, elastin was conventionally described as an amorphous polymer. Recent results in the biomedical, biochemical and biophysical fields have lead to the conclusion that the presence of elastin in the extracellular space has very complex implications involving many other molecules. The present review describes the current state of knowledge concerning elastin as an elastic macromolecule. First, the genetic, biological, biochemical and biophysical processes leading to a functional polymer are described. Second, the elastic function of elastin is discussed. The controversy on elastin structure and elasticity is discussed and a novel dynamic mechanism of elasticity proposed. Finally, pathologies where the elastin molecule is involved are considered. This updated description of functional elastin provides the required background for the understanding of its pathologies and defines clearly the properties a substance should possess to be qualified as a good elastic biomaterial.

  19. Statistical description for survival data

    PubMed Central

    2016-01-01

    Statistical description is always the first step in data analysis. It gives investigator a general impression of the data at hand. Traditionally, data are described as central tendency and deviation. However, this framework does not fit to the survival data (also termed time-to-event data). Such data type contains two components. One is the survival time and the other is the status. Researchers are usually interested in the probability of event at a given survival time point. Hazard function, cumulative hazard function and survival function are commonly used to describe survival data. Survival function can be estimated using Kaplan-Meier estimator, which is also the default method in most statistical packages. Alternatively, Nelson-Aalen estimator is available to estimate survival function. Survival functions of subgroups can be compared using log-rank test. Furthermore, the article also introduces how to describe time-to-event data with parametric modeling. PMID:27867953

  20. A comparison of general and descriptive praise in teaching intraverbal behavior to children with autism.

    PubMed

    Polick, Amy S; Carr, James E; Hanney, Nicole M

    2012-01-01

    Descriptive praise has been recommended widely as an important teaching tactic for children with autism, despite the absence of published supporting evidence. We compared the effects of descriptive and general praise on the acquisition and maintenance of intraverbal skills with 2 children with autism. The results showed slight advantages of descriptive praise in teaching efficiency in the majority of comparisons; however, these effects dissipated over time.

  1. Theoretical description of metabolism using queueing theory.

    PubMed

    Evstigneev, Vladyslav P; Holyavka, Marina G; Khrapatiy, Sergii V; Evstigneev, Maxim P

    2014-09-01

    A theoretical description of the process of metabolism has been developed on the basis of the Pachinko model (see Nicholson and Wilson in Nat Rev Drug Discov 2:668-676, 2003) and the queueing theory. The suggested approach relies on the probabilistic nature of the metabolic events and the Poisson distribution of the incoming flow of substrate molecules. The main focus of the work is an output flow of metabolites or the effectiveness of metabolism process. Two simplest models have been analyzed: short- and long-living complexes of the source molecules with a metabolizing point (Hole) without queuing. It has been concluded that the approach based on queueing theory enables a very broad range of metabolic events to be described theoretically from a single probabilistic point of view.

  2. Computer interpretation of natural language descriptions

    SciTech Connect

    Mellish, C.S.

    1985-01-01

    This description of how a computer program can build up an internal model of a world described in natural languages, concentrates on questions involving the timing of this process. It asks the questions: how does a natural language text convey meaning, and to what extent is it possible to build up an understanding gradually as the book progresses. This approach avoids local ambiguity, providing a system which can use its knowledge of the world effectively to guide interpretation. The author considers the interpretation of pronouns, plural phrases and the simple uses of quantification in the light of a system which can represent and reason about objects which are only partially specified. The work illustrates theoretical ideas by means of a computer program which understands simple mechanics problems stated in English.

  3. Demonstration Advanced Avionics System (DAAS) function description

    NASA Technical Reports Server (NTRS)

    Bailey, A. J.; Bailey, D. G.; Gaabo, R. J.; Lahn, T. G.; Larson, J. C.; Peterson, E. M.; Schuck, J. W.; Rodgers, D. L.; Wroblewski, K. A.

    1982-01-01

    The Demonstration Advanced Avionics System, DAAS, is an integrated avionics system utilizing microprocessor technologies, data busing, and shared displays for demonstrating the potential of these technologies in improving the safety and utility of general aviation operations in the late 1980's and beyond. Major hardware elements of the DAAS include a functionally distributed microcomputer complex, an integrated data control center, an electronic horizontal situation indicator, and a radio adaptor unit. All processing and display resources are interconnected by an IEEE-488 bus in order to enhance the overall system effectiveness, reliability, modularity and maintainability. A detail description of the DAAS architecture, the DAAS hardware, and the DAAS functions is presented. The system is designed for installation and flight test in a NASA Cessna 402-B aircraft.

  4. Theoretical description of RESPIRATION-CP

    NASA Astrophysics Data System (ADS)

    Nielsen, Anders B.; Tan, Kong Ooi; Shankar, Ravi; Penzel, Susanne; Cadalbert, Riccardo; Samoson, Ago; Meier, Beat H.; Ernst, Matthias

    2016-02-01

    We present a quintuple-mode operator-based Floquet approach to describe arbitrary amplitude modulated cross polarization experiments under magic-angle spinning (MAS). The description is used to analyze variants of the RESPIRATION approach (RESPIRATIONCP) where recoupling conditions and the corresponding first-order effective Hamiltonians are calculated, validated numerically and compared to experimental results for 15N-13C coherence transfer in uniformly 13C,15N-labeled alanine and in uniformly 2H,13C,15N-labeled (deuterated and 100% back-exchanged) ubiquitin at spinning frequencies of 16.7 and 90.9 kHz. Similarities and differences between different implementations of the RESPIRATIONCP sequence using either CW irradiation or small flip-angle pulses are discussed.

  5. Stabilization: A Descriptive Framework for Problem Solving

    NASA Astrophysics Data System (ADS)

    Savrda, Sherry L.

    2006-12-01

    An alternative description of problem solving was tested against the think-aloud protocols of twelve introductory calculus-based physics students. Think-aloud protocols are transcripts of problem-solving sessions during which participants are asked to verbalize their thoughts as they attempt to solve a problem. The stabilization model tested considers perceptions of problem difficulty to be related to four primary factors: categorization, goal interpretation, resource relevance, and complexity. A fifth superordinate factor, stabilization, considers the shifting relationships between the four primary factors over the problem-solving process. Problem solving is then described in terms of a search for a stable relationship among the four primary factors. Results from the study to be presented suggest that with further refinement, the stabilization model could be an effective alternative model of problem solving. Results related to the observed problem-solving processes undertaken by the participants will also be presented.

  6. XML Translator for Interface Descriptions

    NASA Technical Reports Server (NTRS)

    Boroson, Elizabeth R.

    2009-01-01

    A computer program defines an XML schema for specifying the interface to a generic FPGA from the perspective of software that will interact with the device. This XML interface description is then translated into header files for C, Verilog, and VHDL. User interface definition input is checked via both the provided XML schema and the translator module to ensure consistency and accuracy. Currently, programming used on both sides of an interface is inconsistent. This makes it hard to find and fix errors. By using a common schema, both sides are forced to use the same structure by using the same framework and toolset. This makes for easy identification of problems, which leads to the ability to formulate a solution. The toolset contains constants that allow a programmer to use each register, and to access each field in the register. Once programming is complete, the translator is run as part of the make process, which ensures that whenever an interface is changed, all of the code that uses the header files describing it is recompiled.

  7. Heavy quarkonia description from a generalized screened potential model

    SciTech Connect

    González, P.

    2016-01-22

    The spectral effect of open flavor meson-meson thresholds in heavy quarkonia is analyzed by using a Non Relativistic Quark Model. The proposed form of the effective quark-antiquark potential, based on lattice indications, incorporates implicitly screening effects from meson-meson configurations. The application of the model to heavy quarkonia provides a resonable description of unconventional J{sup ++} charmonium states and a definite prediction for unconventional J{sup ++} states in bottomonium.

  8. A comparison of two follow-up analyses after multiple analysis of variance, analysis of variance, and descriptive discriminant analysis: A case study of the program effects on education-abroad programs

    Treesearch

    Alvin H. Yu; Garry. Chick

    2010-01-01

    This study compared the utility of two different post-hoc tests after detecting significant differences within factors on multiple dependent variables using multivariate analysis of variance (MANOVA). We compared the univariate F test (the Scheffé method) to descriptive discriminant analysis (DDA) using an educational-tour survey of university study-...

  9. 7 CFR 621.20 - Description.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AGRICULTURE WATER RESOURCES RIVER BASIN INVESTIGATIONS AND SURVEYS Floodplain Management Assistance § 621.20 Description. Floodplain management studies provide needed information and assistance to local and State...

  10. 7 CFR 621.20 - Description.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AGRICULTURE WATER RESOURCES RIVER BASIN INVESTIGATIONS AND SURVEYS Floodplain Management Assistance § 621.20 Description. Floodplain management studies provide needed information and assistance to local and State...

  11. 7 CFR 621.20 - Description.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AGRICULTURE WATER RESOURCES RIVER BASIN INVESTIGATIONS AND SURVEYS Floodplain Management Assistance § 621.20 Description. Floodplain management studies provide needed information and assistance to local and State...

  12. 7 CFR 621.20 - Description.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AGRICULTURE WATER RESOURCES RIVER BASIN INVESTIGATIONS AND SURVEYS Floodplain Management Assistance § 621.20 Description. Floodplain management studies provide needed information and assistance to local and State...

  13. 7 CFR 621.20 - Description.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AGRICULTURE WATER RESOURCES RIVER BASIN INVESTIGATIONS AND SURVEYS Floodplain Management Assistance § 621.20 Description. Floodplain management studies provide needed information and assistance to local and State...

  14. Descriptive Qualities of Athletic Training Education Program Directors

    ERIC Educational Resources Information Center

    Leone, James E.; Judd, Michael R.; Colandreo, Robert M.

    2008-01-01

    Context: Limited literature explores professional preparation of program directors (PD) to lead an athletic training education program (ATEP). Objective: To explore challenges, effectiveness, leadership, and PD role selection. Design: Descriptive and qualitative exploratory email survey. Setting: Educational. Participants: Emails were sent to 345…

  15. Moving Leadership Standards into Everyday Work: Descriptions of Practice.

    ERIC Educational Resources Information Center

    WestEd, San Francisco, CA.

    This publication discusses effective leadership by presenting descriptions of practices for educational leaders. It focuses on six standards, known as the California Professional Standards for Educational Leaders (CPSEL). The California standards, generated from national standards, have been updated and refined to reflect the continuing shift…

  16. Sex-Role Stereotypes and Educators' Descriptions of Mature Personality.

    ERIC Educational Resources Information Center

    Garman, Lynne G.; Plant, Walter T.

    Do educators' descriptions of healthy, mature, socially competent individuals differ as a function of the sex of the person judged? Does the sex of the educator have an effect on the use of sex-role stereotypes? The Stereotype Questionnaire was administered to 126 instructors from every level of education, with instructions to describe a healthy,…

  17. Visual unit analysis: a descriptive approach to landscape assessment

    Treesearch

    R. J. Tetlow; S. R. J. Sheppard

    1979-01-01

    Analysis of the visible attributes of landscapes is an important component of the planning process. When landscapes are at regional scale, economical and effective methodologies are critical. The Visual Unit concept appears to offer a logical and useful framework for description and evaluation. The concept subdivides landscape into coherent, spatially-defined units....

  18. Route Description in Iwaidja: Grammar and Conceptualisation of Motion

    ERIC Educational Resources Information Center

    Edmonds-Wathen, Cris

    2016-01-01

    This study focussed on the effect of grammar of Iwaidja, an indigenous Australian language, on mathematical conceptualisation. It investigated route description in Iwaidja. Spatial concepts such as direction, height and movement in relation to another object are briefly described using examples. Differences between English and Iwaidja are used to…

  19. 42 CFR 456.241 - Purpose and general description.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Ur Plan: Medical Care Evaluation Studies § 456.241 Purpose and general description. (a) The purpose of medical care evaluation studies is to promote the most effective and efficient use of available... health care. (b) Medical care evaluation studies— (1) Emphasize identification and analysis of patterns...

  20. 42 CFR 456.141 - Purpose and general description.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS UTILIZATION CONTROL Utilization Control: Hospitals Ur Plan: Medical Care Evaluation Studies § 456.141 Purpose and general description. (a) The purpose of medical care evaluation studies is to promote the most effective and efficient use of available health facilities and...