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Sample records for haas-van alphen effect

  1. de Haas-van Alphen Effect of CeSb Under Pressure

    NASA Astrophysics Data System (ADS)

    Takashita, Masahiro; Aoki, Haruyoshi; Haworth, Christopher; Matsumoto, Takehiko; Terashima, Taichi; Uji, Shinya; Terakura, Chieko; Miura, Takahiro; Uesawa, Akihiro; Suzuki, Takashi

    1998-11-01

    We report a de Haas-van Alphen effect study of CeSb in thehigh-field ferromagnetic (F)and intermediate-field antiferromagnetic (AFF1) phases.In the F phase, the frequencies ofthe electron surfaces increase monotonically with pressure.On the other hand, the frequency ofone particular hole surface increases with pressure,while those of the other hole surfaces decrease slightly.The effective masses of all the hole surfaces increase similarlywith pressure, while those of the electron surfaces change little.In the AFF1 phase, other hole surfaces than theparticular one have qualitatively different pressure dependencefrom that in the F phase.The frequency changes both in the Fand AFF1 phases can be explainedby taking the anisotropic p-f mixing model into account.However, it is difficult to understandthe changes of the effective masses in termsof the f content expected for the p-f mixing model.

  2. Quantum Oscillations without a Fermi Surface and the Anomalous de Haas-van Alphen Effect

    NASA Astrophysics Data System (ADS)

    Knolle, Johannes; Cooper, Nigel R.

    2015-10-01

    The de Haas-van Alphen effect (dHvAE), describing oscillations of the magnetization as a function of magnetic field, is commonly assumed to be a definite sign for the presence of a Fermi surface (FS). Indeed, the effect forms the basis of a well-established experimental procedure for accurately measuring FS topology and geometry of metallic systems, with parameters commonly extracted by fitting to the Lifshitz-Kosevich (LK) theory based on Fermi liquid theory. Here we show that, in contrast to this canonical situation, there can be quantum oscillations even for band insulators of certain types. We provide simple analytic formulas describing the temperature dependence of the quantum oscillations in this setting, showing strong deviations from LK theory. We draw connections to recent experiments and discuss how our results can be used in future experiments to accurately determine, e.g., hybridization gaps in heavy-fermion systems.

  3. Fermiology and De Haas-van Alphen effect of {beta}-(ET){sub 2}IBr{sub 2}

    SciTech Connect

    Wosnitza, J.; Crabtree, G.W.; Carlson, K.D.; Wang, H.H.; Williams, J.M.

    1993-04-01

    The Fermi surface of the organic superconductor {beta}-(ET){sub 2}IBr{sub 2} investigated by measurements of the de Haas - van Alphen (dHvA) effect has been found to have the typical two-dimensional cylindrical form. A small amount of corrugation could be quantitatively determined by the distinctive angular dependence of beating nodes. the existence of up to four almost identical frequencies in the dHvA signal may be explained by magnetic interaction effects within the samples. Due to the 1/cos{Theta}- behavior of the effective mass spin-splitting zeros could be detected.

  4. Fermi surface of SrFe2P2 determined by de Haas-van Alphen effect

    SciTech Connect

    Analytis, J.G.

    2010-05-26

    We report measurements of the Fermi surface (FS) of the ternary iron-phosphide SrFe{sub 2}P{sub 2} using the de Haas-van Alphen effect. The calculated FS of this compound is very similar to SrFe{sub 2}As{sub 2}, the parent compound of the high temperature superconductors. Our data show that the Fermi surface is composed of two electron and two hole sheets in agreement with bandstructure calculations. Several of the sheets show strong c-axis warping emphasizing the importance of three-dimensionality in the non-magnetic state of the ternary pnictides. We find that the electron and hole pockets have a different topology, implying that this material does not satisfy a ({pi},{pi}) nesting condition.

  5. De Haas-van Alphen Effect and Fermi Surface Properties in Ferromagnet LaCo2P2 and Related Compounds

    NASA Astrophysics Data System (ADS)

    Teruya, Atsushi; Nakamura, Ai; Takeuchi, Tetsuya; Honda, Fuminori; Aoki, Dai; Harima, Hisatomo; Uchima, Kiyoharu; Hedo, Msato; Nakama, Takao; Ōnuki, Yoshichika

    We grew single crystals of a ferromagnet LaCo2P2 and an antiferromagnet CaCo2P2, and clarified the magnetic properties by measuring the electrical resistivity, specific heat, magnetic susceptibility, and magnetization. For LaCo2P2, we also carried out the de Haas-van Alphen (dHvA) experiment. Detected dHvA branches are well explained by the results of energy band calculations using a full-potential linearized augmented plane wave method within the local spin density approximation, where the ferromagnetic state is assumed. The cyclotron effective masses are (2-3)m0 (m0: rest mass of an electron). The present relatively large cyclotron masses in LaCo2P2 are due to ferromagnetic correlations of Co-3d conduction electrons, which are compared with much larger cyclotron masses of (3-7)m0 for a nearly ferromagnet SrCo2P2.

  6. De Haas-van Alphen effect and energy gaps of a correlated two-dimensional electron system in an AlAs two-valley pseudospin system

    NASA Astrophysics Data System (ADS)

    Windisch, T.; Huang, X.; Dasgupta, S.; Rupprecht, B.; Heyn, Ch.; Bichler, M.; Fontcuberta I Morral, A.; Grayson, M.; Abstreiter, G.; Wilde, M. A.; Grundler, D.

    2009-11-01

    We report highly sensitive de Haas-van Alphen (dHvA) effect measurements on a high-mobility two-dimensional electron system in an AlAs quantum well. Here two valleys are occupied forming a pseudospin system. At 400 mK, the dHvA effect shows pronounced oscillations at filling factors ν=1 to four. In the quantum limit at ν=1 the data are consistent with an interaction-enhanced valley splitting, which exceeds the Zeeman spin splitting in a perpendicular field B . When tilting B the energy gap ΔE at ν=1 shows first an unexpectedly strong angular dependence and then remains constant. This suggests a crossover in the energy gap, most likely from a spin to a pseudospin gap. We attribute the strong initial dependence of ΔE on the tilt angle to skyrmion-type spin excitations. Surprisingly, the dHvA oscillation amplitudes do not display coincidence phenomena at higher filling factors. This is explained by the large valley splitting and avoided crossings of energy levels.

  7. High field magnetoresistance and de Haas-van Alphen effect in antiferromagnetic PrB/sub 6/ and NdB/sub 6/

    SciTech Connect

    Onuki, Y.; Umezawa, A.; Kwok, W.K.; Crabtree, G.W.; Nishihara, M.; Yamazaki, T.; Omi, T.; Komatsubara, T.

    1987-08-01

    The transport properties and the de Haas-van Alphen (dHvA) effect have been measured for antiferromagnetic PrB/sub 6/ and NdB/sub 6/. The number of conduction electrons is approximately one per unit cell. The magnetoresistance shows the existence of open orbits implying a multiply connected Fermi surface. The angular dependence of the magnetoresistance is roughly similar to that of the reference material, LaB/sub 6/. The dHvA data in PrB/sub 6/ shows both paramagnetic and antiferromagnetic Fermi surfaces. The antiferromagnetic Fermi surface arises from new magnetic Brillouin zone boundaries and antiferromagnetic gaps introduced by the magnetic order, and the paramagnetic Fermi surface from magnetic breakdown through the small antiferromagnetic gaps in high field. Hybridization between the conduction electrons and the f electrons has been observed through the cyclotron masses, which in PrB/sub 6/ are three times larger than the corresponding masses of LaB/sub 6/. In NdB/sub 6/ only the antiferromagnetic Fermi surface, quite different from those of LaB/sub 6/ and PrB/sub 6/, has been observed. 26 refs., 10 figs., 3 tabs.

  8. de Haas-van Alphen oscillations for neutral atoms in electric fields

    NASA Astrophysics Data System (ADS)

    Farias, B.; Furtado, C.

    2016-07-01

    The de Haas-van Alphen (dHvA) effect is well known as an oscillatory variation of the magnetization of conductors as a function of the inverse magnetic field and the frequency is proportional to the area of the Fermi surface. Here, we show that an analogous effect can occur for neutral atoms with a nonvanishing magnetic moment interacting with an electric field. Under an appropriate field-dipole configuration, the neutral atoms subject to a synthetic magnetic field arrange themselves in Landau levels. Using the Landau-Aharonov-Casher (LAC) theory, we obtain the energy eigenfunctions and eigenvalues as well as the degeneracy of the system. In a strong effective magnetic field regime we present the quantum oscillations in the energy and effective magnetization of a two-dimensional (2D) atomic gas. From the dHvA period we determine the area of the Fermi circle of the atomic cloud.

  9. De Haas-van Alphen oscillations in the charge-density wave compound lanthanum tritelluride (LaTe3)

    SciTech Connect

    Ru, N.; Borzi, R.A.; Rost, A.; Mackenzie, A.P.; Laverock, J.; Dugdale, S.B.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2009-12-14

    De Haas-van Alphen oscillations were measured in lanthanum tritelluride (LaTe{sub 3}) to probe the partially gapped Fermi surface resulting from charge density wave (CDW) formation. Three distinct frequencies were observed, one of which can be correlated with a FS sheet that is unaltered by CDW formation. The other two frequencies arise from FS sheets that have been reconstructed in the CDW state.

  10. High magnetic field calibration using de Haas-van Alphen oscillations in polycrystalline copper

    NASA Astrophysics Data System (ADS)

    Coniglio, William A.; Williams, Alan F.; Yannakopoulos, Anna; Grockowiak, Audrey; Tozer, Stan

    We provide a calibration for the de Haas-van Alphen (dHvA) frequency in polycrystalline copper, which may be used to standardize the measurement of magnetic fields, particularly in pulsed field environments, where direct observation of NMR is challenging. Using a reliable single-crystal model of the Fermi surface from coefficients that are traceable to a powder Al NMR reference, we computed Fermi surface extremal areas for evenly spaced directions around a sphere. Summing the peaks corresponding to extremal orbits according to the Lifshitz-Kosevich model, we arrive at a dHvA spectrum that corresponds to experimental observation. We find that actual maximum fields reached at the NHMFL-Pulsed Field Facility are slightly larger than previously determined. We appreciate generous primary support from the U. S. Department of Energy NNSA SSAA DE-NA0001979. The National High Magnetic Field Laboratory is supported by the National Science Foundataion, U. S. Department of Energy, and the State of Florida.

  11. Note on de Haas-van Alphen diamagnetism in thin, free-electron films

    NASA Astrophysics Data System (ADS)

    Grzesik, J. A.

    2012-03-01

    We revisit the problem of de Haas-van Alphen (dHvA) diamagnetic susceptibility oscillations in a thin, free-electron film trapped in a synthetic harmonic potential well. A treatment of this phenomenon at zero temperature was announced many years ago by Childers and Pincus (designated hereafter as CP), and we traverse initially much the same ground, but from a slightly different analytic perspective. That difference hinges around our use, in calculating the Helmholtz free energy F, of an inverse Laplace transform, Bromwich-type contour integral representation for the sharp distribution cutoff at Fermi level μ. The contour integral permits closed-form summation all at once over the discrete orbital Landau energy levels transverse to the magnetic field, and the energy associated with the in-plane canonical momenta ℏ k x and ℏ k z. Following such summation/integration, pole/residue pairs appear in the plane of complex transform variable s, a fourth-order pole at origin s = 0, and an infinite ladder, both up and down, of simple poles along the imaginary axis. The residue sum from the infinite pole ladder automatically engenders a Fourier series with period one in dimensionless variable μ/ ℏ ω (with effective angular frequency ω suitably defined), series which admits closed-form summation as a cubic polynomial within any given periodicity slot. Such periodicity corresponds to Landau levels slipping sequentially beneath Fermi level μ as the ambient magnetic field H declines in strength, and is manifested by the dHvA pulsations in diamagnetic susceptibility. The coëxisting steady contribution from the pole at origin has a similar cubic structure but is opposite in sign, inducing a competition whose outcome is a net magnetization that is merely quadratic in any given periodicity slot, modulated by a slow amplitude growth. Apart from some minor notes of passing discord, these simple algebraic structures confirm most of the CP formulae, and their graphic display

  12. De Haas-van Alphen Effect in Rh2Ga9 and Ir2Ga9 without Inversion Symmetry in the Crystal Structure and Related Compounds T2Al9 (T: Co, Rh, Ir) with Inversion Symmetry

    NASA Astrophysics Data System (ADS)

    Takeda, Masataka; Teruya, Atsushi; Nakamura, Ai; Harima, Hisatomo; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika

    2015-02-01

    We succeeded in growing high-quality single crystals of Rh2Ga9 and Ir2Ga9 with the non-centrosymmetric (distorted Co2Al9-type) monoclinic structure by the Ga-self flux method, and carried out the de Haas-van Alphen (dHvA) experiments. The Fermi surface is found to be split into two different Fermi surfaces, reflecting the non-centrosymmetric crystal structure. A magnitude of the antisymmetric spin-orbit interaction or a splitting energy between the two Fermi surfaces are determined to be 56 K for dHvA branch α and 45 K for branch β in Rh2Ga9, where these dHvA branches correspond to main Fermi surfaces. The present splitting values are compared with 290 and 130 K in Ir2Ga9, respectively. The splitting energy is found to be larger in the Ir-5d conduction electrons than in the Rh-4d conduction electrons. The split dHvA branches in Rh2Ga9 and Ir2Ga9 are also compared with the single dHvA branch in Co2Al9, Rh2Al9, and Ir2Al9 with inversion symmetry in the crystal structure.

  13. Fermi surface of MoO2 studied by angle-resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations

    NASA Astrophysics Data System (ADS)

    Moosburger-Will, Judith; Kündel, Jörg; Klemm, Matthias; Horn, Siegfried; Hofmann, Philip; Schwingenschlögl, Udo; Eyert, Volker

    2009-03-01

    A comprehensive study of the electronic properties of monoclinic MoO2 from both an experimental and a theoretical point of view is presented. We focus on the investigation of the Fermi body and the band structure using angle-resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations. For the latter, the full-potential augmented spherical wave method has been applied. Very good agreement between the experimental and theoretical results is found. In particular, all Fermi surface sheets are correctly identified by all three approaches. Previous controversies concerning additional holelike surfaces centered around the Z and B points could be resolved; these surfaces were artifacts of the atomic-sphere approximation used in the old calculations. Our results underline the importance of electronic structure calculations for the understanding of MoO2 and the neighboring rutile-type early transition-metal dioxides. This includes the low-temperature insulating phases of VO2 and NbO2 , which have crystal structures very similar to that of molybdenum dioxide and display the well-known prominent metal-insulator transitions.

  14. Quantum Hall conductance and de Haas-van Alphen oscillation in a tight-binding model with electron and hole pockets for (TMTSF) 2NO3

    NASA Astrophysics Data System (ADS)

    Kishigi, Keita; Hasegawa, Yasumasa

    2016-08-01

    Quantized Hall conductance and de Haas-van Alphen (dHvA) oscillation are studied theoretically in the tight-binding model for (TMTSF) 2NO3 , in which there are small pockets of electrons and holes due to the periodic potentials of anion ordering in the a direction. The magnetic field is treated by hoppings as complex numbers due to the phase caused by the vector potential, i.e., Peierls substitution. In realistic values of parameters and the magnetic field, the energy as a function of the magnetic field (Hofstadter butterfly diagram) is obtained. It is shown that the energy levels are broadened and the gaps are closed or almost closed periodically as a function of the inverse magnetic field, which is not seen in the semiclassical theory of the magnetic breakdown. The Hall conductance is quantized with an integer obtained by the Diophantine equation when the chemical potential lies in an energy gap. When electrons or holes are doped in this system, the Hall conductance is quantized in some regions of a magnetic field but it is not quantized in other regions of a magnetic field due to the broadening of the Landau levels. The amplitude of the dHvA oscillation at zero temperature decreases as the magnetic field increases, while it is constant in the semiclassical Lifshitz Kosevich formula.

  15. De Hass-van Alphen effect in YBCO

    SciTech Connect

    Smith, J.L.; Fowler, C.M.; Freeman, B.L.; Hults, W.L.; King, J.C.; Mueller, F.M.

    1990-01-01

    Measurement of the de Haas-van Alphen effect in YBa{sub 2}Cu{sub 3}O{sub 6.97} in pulsed, magnetic fields peaking at 100 T in powdered material with the field applied along the c-axis reveal two pieces of the Fermi surface. Their cross sections are 0.56 kT (0.054 {angstrom}{sup {minus}2}) and 0.78 kT (0.075 {angstrom}{sup {minus}2}) with effective masses of 2.8 and 4.4 respectively.

  16. Room temperature de Haas–van Alphen effect in silicon nanosandwiches

    NASA Astrophysics Data System (ADS)

    Bagraev, N. T.; Grigoryev, V. Yu.; Klyachkin, L. E.; Malyarenko, A. M.; Mashkov, V. A.; Romanov, V. V.

    2016-08-01

    The negative-U impurity stripes confining the edge channels of semiconductor quantum wells are shown to allow the effective cooling inside in the process of the spin-dependent transport. The aforesaid promotes also the creation of composite bosons and fermions by the capture of single magnetic flux quanta on the edge channels under the conditions of low sheet density of carriers, thus opening new opportunities for the registration of the quantum kinetic phenomena in weak magnetic fields at high temperatures up to the room temperature. As a certain version noted above we present the first findings of the high temperature de Haas-van Alphen, 300K, and quantum Hall, 77K, effects in the silicon sandwich structure that represents the ultra-narrow, 2 nm, p-type quantum well (Si-QW) confined by the delta barriers heavily doped with boron on the n-type Si (100) surface. These data appear to result from the low density of single holes that are of small effective mass in the edge channels of p-type Si-QW because of the impurity confinement by the stripes consisting of the negative-U dipole boron centers which seems to give rise to the efficiency reduction of the electron-electron interaction.

  17. Effects of oxygen plasma etching on Sb2Te3 explored by torque detected quantum oscillations

    NASA Astrophysics Data System (ADS)

    Yan, Yuan; Heintze, Eric; Pracht, Uwe S.; Blankenhorn, Marian; Dressel, Martin

    2016-04-01

    De Haas-van Alphen measurements evidence that oxygen plasma etching strongly affects the properties of the three-dimensional topological insulator Sb2Te3. The quantum oscillations in magnetization down to low temperature (T ≥ 2 K) and high magnetic field (B ≤ 7 T) have been systematically investigated using a high-sensitive cantilever torque magnetometer. The effective mass and the oscillation frequency obtained from de Haas-van Alphen measurements first increase and then decrease as the oxygen plasma etching time increases from 0 to 12 min, corresponding to an up- and down-shift of the Dirac point. We establish the cantilever torque magnetometer as a powerful contactless tool to investigate the oxygen sensitivity of the surface state in topological insulators.

  18. Effect of structural disorder on quantum oscillations in graphite

    NASA Astrophysics Data System (ADS)

    Camargo, B. C.; Kopelevich, Y.; Usher, A.; Hubbard, S. B.

    2016-01-01

    We have studied the effect of structural disorder on the de Haas van Alphen and Shubnikov de Haas quantum oscillations measured in natural, Kish, and highly oriented pyrolytic graphite samples at temperatures down to 30 mK and at magnetic fields up to 14 T. The measurements were performed on different samples characterized by means of x-ray diffractometry, transmission electron microscopy, and atomic-force microscopy techniques. Our results reveal a correlation between the amplitude of quantum oscillations and the sample surface roughness.

  19. de Haas-van Alphen measurements in Ba{sub 0.6}K{sub 0.4}BiO{sub 3}

    SciTech Connect

    Goodrich, R.G.; Grienier, C.; Hall, D.

    1993-08-01

    dHvA measurements were made on the 32 K cubic superconductor Ba{sub 0.6}K{sub 0.4}BiO{sub 3} using a 50 Tesla pulsed field magnet at NHMFL (Los Alamos) and a 18 T superconducting magnet (LSU). Data were taken with the magnetic field aligned along the (001) direction, at 1.5 to 3.9 K. The pulsed fields were high enough to drive the system well into the normal state. Analysis shows that the frequencies of the observed dHvA oscillations arise from a several Fermi surface sheets. One cross section was nearly identical with that predicted by a new LDA calculation.

  20. Enhancement of the cyclotron effective mass in U0.03Th0.97Ru2Si2

    NASA Astrophysics Data System (ADS)

    Haga, Yoshinori; Matsumoto, Yuji; Tateiwa, Naoyuki; Yamamoto, Etsuji; Kimura, Noriaki; Yamamura, Tomoo; Fisk, Zachary

    2015-03-01

    Electronic states of a dilute uranium alloy U0.03Th0.97Ru2Si2 have been investigated by using de Haas-van Alphen (dHvA) measurements on single crystal samples. Quantum oscillations were successfully observed for the field along the principal axes. The dHvA frequency of the observed branches roughly agrees with those of the reference compound ThRu2Si2, indicating the change of Fermi surface volume is not significant. On the other hand, the dHvA amplitude is strongly diminished compared to ThRu2Si2. Furthermore, cyclotron effective masses for corresponding branches are strongly enhanced. The latter effects are indicative of the strong scattering as well as the mass renormalization due to 5f moments.

  1. Shubnikov-de Haas and high-field magnetoresistance effects in the A15 compound Nb/sub 3/Sb

    SciTech Connect

    Sellmyer, D.J.; Liebowitz, D.; Arko, A.J.; Fisk, Z.

    1980-09-01

    High-field magnetoresistance and Shubinikob-de Haas (SdH) effects were studied in the A15 compound Nb/sub 3/Sb in fields up to 215 kG. A change in the field dependence of the magnetoresistance for certain field directions above about 150 kG appears to signal the onset of magnetic breakdown. Five sets of SdH frequencies were observed, four of them closely corresponding to de Haas-van Alphen (dHvA) frequencies observed by Arko et al. The fifth frequency has an extremely large amplitude, about 20% of the background magnetoresistance, and it is suggested that this also is due to magnetic breakdown. The results are compared with the ab initio band calculations of van Kellel et al., which can explain many of the observed features of the dHvA and SdH frequencies.

  2. Split Fermi Surface Properties based on the Relativistic Effect in Superconductor PdBiSe with the Cubic Chiral Crystal Structure

    NASA Astrophysics Data System (ADS)

    Kakihana, Masashi; Nakamura, Ai; Teruya, Atsushi; Harima, Hisatomo; Haga, Yoshinori; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika

    2015-03-01

    We grew single crystals of PdBiSe with the ullmannite-type cubic chiral structure and carried out de Haas-van Alphen (dHvA) experiments to clarify the Fermi surface properties. The Fermi surfaces are found to split into two different Fermi surfaces, reflecting the non-centrosymmetric crystal structure. A splitting energy between two nearly spherical Fermi surfaces named α and α' is determined as 1050-1260 K. These Fermi surfaces are identified to be due the band-149 and -150 electron Fermi surfaces centered at the Γ point from the results of full-potential linearized augmented plane wave (FLAPW) energy band calculations under consideration of a mass correction in the spin-orbit interaction for Bi-6p electrons based on the relativistic effect. The theoretical splitting energy between these Fermi surfaces is 1080-1150 K, which is in good agreement with the experimental value.

  3. Correlations and effects of pressure in Fe-pnictides

    NASA Astrophysics Data System (ADS)

    Valenti, Roser

    2014-03-01

    In this talk we will explore the effects of correlations and pressure in Fe-based superconductors by considering a combination of density functional theory calculations and dynamical mean field theory and compare our results with recent ARPES and de Haas van Alphen experiments. We will discuss the importance of orbital-selective correlations in the 111 (LiFeAs, LiFeP) and 122 families (BaFe2As2,CaFe2As2, KFe2As2) and indicate how the topology of the Fermi surface, specially in KFe2As2, is influenced by these effects. In this context, we will show why MgFeGe, an isostructural and isoelectronic system to LiFeAs, doesn't superconduct. In the case of the 122 systems, we will predict and analyze changes in the electronic and magnetic properties under hydrostatic, tensile and compressive pressure and will discuss our results in relation to (i) superconductivity, (ii) magnetism and (iii) the mechanisms involved in the detwinning process of an orthorhombic iron-pnictide crystal a. Funding has been provided by the German Science Foundation (DFG).

  4. Field-Induced Lifshitz Transition without Metamagnetism in CeIrIn5

    NASA Astrophysics Data System (ADS)

    Aoki, D.; Seyfarth, G.; Pourret, A.; Gourgout, A.; McCollam, A.; Bruin, J. A. N.; Krupko, Y.; Sheikin, I.

    2016-01-01

    We report high magnetic field measurements of magnetic torque, thermoelectric power, magnetization, and the de Haas-van Alphen effect in CeIrIn5 across 28 T, where a metamagnetic transition was suggested in previous studies. The thermoelectric power displays two maxima at 28 and 32 T. Above 28 T, a new, low de Haas-van Alphen frequency with a strongly enhanced effective mass emerges, while the highest frequency observed at low field disappears entirely. This suggests a field-induced Lifshitz transition. However, longitudinal magnetization does not show any anomaly up to 33 T, thus ruling out a metamagnetic transition at 28 T.

  5. Confinement and inhomogeneous broadening effects in the quantum oscillatory magnetization of quantum dot ensembles.

    PubMed

    Herzog, F; Heedt, S; Goerke, S; Ibrahim, A; Rupprecht, B; Heyn, Ch; Hardtdegen, H; Schäpers, Th; Wilde, M A; Grundler, D

    2016-02-01

    We report on the magnetization of ensembles of etched quantum dots with a lateral diameter of 460 nm, which we prepared from InGaAs/InP heterostructures. The quantum dots exhibit 1/B-periodic de-Haas-van-Alphen-type oscillations in the magnetization M(B) for external magnetic fields B  >  2 T, measured by torque magnetometry at 0.3 K. We compare the experimental data to model calculations assuming different confinement potentials and including ensemble broadening effects. The comparison shows that a hard wall potential with an edge depletion width of 100 nm explains the magnetic behavior. Beating patterns induced by Rashba spin-orbit interaction (SOI) as measured in unpatterned and nanopatterned InGaAs/InP heterostructures are not observed for the quantum dots. From our model we predict that signatures of SOI in the magnetization could be observed in larger dots in tilted magnetic fields. PMID:26740509

  6. Field-Induced Lifshitz Transition without Metamagnetism in CeIrIn(5).

    PubMed

    Aoki, D; Seyfarth, G; Pourret, A; Gourgout, A; McCollam, A; Bruin, J A N; Krupko, Y; Sheikin, I

    2016-01-22

    We report high magnetic field measurements of magnetic torque, thermoelectric power, magnetization, and the de Haas-van Alphen effect in CeIrIn_{5} across 28 T, where a metamagnetic transition was suggested in previous studies. The thermoelectric power displays two maxima at 28 and 32 T. Above 28 T, a new, low de Haas-van Alphen frequency with a strongly enhanced effective mass emerges, while the highest frequency observed at low field disappears entirely. This suggests a field-induced Lifshitz transition. However, longitudinal magnetization does not show any anomaly up to 33 T, thus ruling out a metamagnetic transition at 28 T. PMID:26849611

  7. Intrinsic Perturbation of the Landau Levels in Metals and Semiconductors at Low Temperatures

    NASA Astrophysics Data System (ADS)

    Awobode, Ayodeji

    2009-03-01

    The de Haas--van Alphen effect in non-superconducting metals and semiconductors at very low temperatures is proposed as a test of an intrinsic perturbative term which appears in the Landau equation sequel to the modification of the Pauli equation. Corrections to the frequency (or period) of the de Haas--van Alphen oscillation in metals is calculated and shown to depend on the Fermi energy and the measured anomalous part of the electron magnetic moment. Precision measurement of the magneto-optical properties which arise from the motion of electrons in binary semiconductors placed in a weak magnetic field is also proposed as a means of observing very small changes in the.

  8. Shubnikov--de Haas effect in the superconducting state of an organic superconductor

    SciTech Connect

    Wosnitza, J.; Wanka, S.; Hagel, J.; Ha''ussler, R.; Lo''hneysen, H. v.; Schlueter, J. A.; Geiser, U.; Nixon, P. G.; Winter, R. W.; Gard, G. L.

    2000-11-01

    We report the observation of Shubnikov--de Haas (SdH) oscillations in the mixed state of the organic superconductor {beta}''-(BEDT-TTF){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} (T{sub c}{approx}4.4K). At low temperatures the SdH oscillations persist clearly below the upper critical field B{sub c2}(0){approx}3.6T almost down to the field where the resistivity vanishes. Rather unusually, no additional damping of the SdH-signal amplitude -- as well as of the de Haas--van Alphen amplitude -- is observed in the superconducting state. This indicates that the damping in the vortex state of this quasi-two-dimensional superconductor is different in character to that observed for most three-dimensional materials.

  9. De Hass-van Alphen and magnetoresistance reveal predominantly single-band transport behavior in PdTe2

    PubMed Central

    Wang, Yongjian; Zhang, Jinglei; Zhu, Wenka; Zou, Youming; Xi, Chuanying; Ma, Long; Han, Tao; Yang, Jun; Wang, Jingrong; Xu, Junmin; Zhang, Lei; Pi, Li; Zhang, Changjin; Zhang, Yuheng

    2016-01-01

    Research on two-dimensional transition metal dichalcogenides (TMDs) has grown rapidly over the past several years, from fundamental studies to the development of next generation technologies. Recently, it has been reported that the MX2-type PdTe2 exhibits superconductivity with topological surface state, making this compound a promising candidate for investigating possible topological superconductivity. However, due to the multi-band feature of most of TMDs, the investigating of magnetoresistance and quantum oscillations of these TMDs proves to be quite complicated. Here we report a combined de Hass-van Alphen effect and magnetoresistance studies on the PdTe2 single crystal. Our high-field de Hass-van Alphen data measured at different temperature and different tilting angle suggest that though these is a well-defined multi-band feature, a predominant oscillation frequency has the largest oscillation magnitude in the fast Fourier transformation spectra, which is at least one order of magnitude larger than other oscillation frequencies. Thus it is likely that the transport behavior in PdTe2 system can be simplified into a single-band model. Meanwhile, the magnetoresistance results of the PdTe2 sample can be well-fitted according to the single-band models. The present results could be important in further investigation of the transport behaviors of two-dimensional TMDs. PMID:27516134

  10. De Hass-van Alphen and magnetoresistance reveal predominantly single-band transport behavior in PdTe2.

    PubMed

    Wang, Yongjian; Zhang, Jinglei; Zhu, Wenka; Zou, Youming; Xi, Chuanying; Ma, Long; Han, Tao; Yang, Jun; Wang, Jingrong; Xu, Junmin; Zhang, Lei; Pi, Li; Zhang, Changjin; Zhang, Yuheng

    2016-01-01

    Research on two-dimensional transition metal dichalcogenides (TMDs) has grown rapidly over the past several years, from fundamental studies to the development of next generation technologies. Recently, it has been reported that the MX2-type PdTe2 exhibits superconductivity with topological surface state, making this compound a promising candidate for investigating possible topological superconductivity. However, due to the multi-band feature of most of TMDs, the investigating of magnetoresistance and quantum oscillations of these TMDs proves to be quite complicated. Here we report a combined de Hass-van Alphen effect and magnetoresistance studies on the PdTe2 single crystal. Our high-field de Hass-van Alphen data measured at different temperature and different tilting angle suggest that though these is a well-defined multi-band feature, a predominant oscillation frequency has the largest oscillation magnitude in the fast Fourier transformation spectra, which is at least one order of magnitude larger than other oscillation frequencies. Thus it is likely that the transport behavior in PdTe2 system can be simplified into a single-band model. Meanwhile, the magnetoresistance results of the PdTe2 sample can be well-fitted according to the single-band models. The present results could be important in further investigation of the transport behaviors of two-dimensional TMDs. PMID:27516134

  11. Fermi surface, magnetic, and superconducting properties in actinide compounds

    NASA Astrophysics Data System (ADS)

    Ōnuki, Yoshichika; Settai, Rikio; Haga, Yoshinori; Machida, Yo; Izawa, Koichi; Honda, Fuminori; Aoki, Dai

    2014-08-01

    The de Haas-van Alphen effect, which is a powerful method to explore Fermi surface properties, has been observed in cerium, uranium, and nowadays even in neptunium and plutonium compounds. Here, we present the results of several studies concerning the Fermi surface properties of the heavy fermion superconductors UPt3 and NpPd5Al2, and of the ferromagnetic pressure-induced superconductor UGe2, together with those of some related compounds for which fascinating anisotropic superconductivity, magnetism, and heavy fermion behavior has been observed. xml:lang="fr"

  12. Heavy-electron materials

    SciTech Connect

    Fisk, Z.; Ott, H.R.; Smith, J.L.

    1986-01-01

    De Haas-van Alphen results demonstrated the existence of a Fermi surface at sufficiently low temperature and show that the entire Fermi surface involves heavy electrons. The phase transitions in their heavy-electron state are discussed. These are either magnetic or superconducting. 38 refs., 6 figs., 2 tabs. (WRF)

  13. Holographic non-Fermi liquid in a background magnetic field

    NASA Astrophysics Data System (ADS)

    Basu, Pallab; He, Jianyang; Mukherjee, Anindya; Shieh, Hsien-Hang

    2010-08-01

    We study the effects of a nonzero magnetic field on a class of 2+1 dimensional non-Fermi liquids, recently found in [Hong Liu, John McGreevy, and David Vegh, arXiv:0903.2477.] by considering properties of a Fermionic probe in an extremal AdS4 black hole background. Introducing a similar fermionic probe in a dyonic AdS4 black hole geometry, we find that the effect of a magnetic field could be incorporated in a rescaling of the probe fermion’s charge. From this simple fact, we observe interesting effects like gradual disappearance of the Fermi surface and quasiparticle peaks at large magnetic fields and changes in other properties of the system. We also find Landau level like structures and oscillatory phenomena similar to the de-Haas-van Alphen effect.

  14. Itinerant 5 f Electrons and the Fermi Surface Properties in an Enhanced Pauli Paramagnet NpGe3

    NASA Astrophysics Data System (ADS)

    Aoki, Dai; Yamagami, Hiroshi; Homma, Yoshiya; Shiokawa, Yoshinobu; Yamamoto, Etsuji; Nakamura, Akio; Haga, Yoshinori; Settai, Rikio; Ōnuki, Yoshichika

    2005-08-01

    We succeeded in growing a high-quality single crystal of an enhanced Pauli paramagnet, NpGe3, by the Bi-flux method, and observed the de Haas-van Alphen (dHvA) effect. The topology of a Fermi surface is well explained by the relativistic linear augmented-plane-wave (LAPW) band calculations based on the 5 f itinerant band model. The Fermi surface consists of a nearly spherical electron-Fermi surface with necks along the < 100 > direction, forming a hollow ball, centered at the R point, which is derived from the single band. The cyclotron effective mass is in the range from 2.6 to 16 m0, which is enhanced approximately 3.5 times from the corresponding band mass.

  15. Ultrasonic probe of the AuZn Fermi surface.

    SciTech Connect

    Svitelskiy, O.; Suslov, A. V.; Singleton, J. M.; Lashley, J. C.

    2005-01-01

    We, for the first time, apply the ultrasonic pulse-echo technique to explore the Fermi surface of the martensite phase of the single crystalline AuZn shape memory alloy. The ultrasonic measurements were performed in the magnetic fields of up to 45 T in the temperature range of 0.07 < T < 300 K. In the martensite phase (T < 64 K), the oscillations of the speed of the longitudinal sound wave propagating in the (110) direction indicated a strong acoustic de Haas - van Alphen effect. In addition to the earlier described oscillations with frequencies of 1140 and 4720 Tesla, we observed a new frequency of 120 Tesla, which was predicted theoretically. Corresponding effective masses were in favorable agreement with those expected from band structure calculations.

  16. On the quantum magnetic oscillations of electrical and thermal conductivities of graphene

    NASA Astrophysics Data System (ADS)

    Alisultanov, Z. Z.; Reis, M. S.

    2016-05-01

    Oscillating thermodynamic quantities of diamagnetic materials, specially graphene, have been attracting attention of the scientific community due to the possibility to experimentally map the Fermi surface of the material. These have been the case of the de Haas-van Alphen and Shubnikov-de Haas effects, found on the magnetization and electrical conductivity, respectively. In this direction, managing the thermodynamic oscillations is of practical purpose, since from the reconstructed Fermi surface it is possible to access, for instance, the electronic density. The present work theoretically explores the quantum oscillations of electrical and thermal conductivities of a monolayer graphene under a crossed magnetic and electric fields. We found that the longitudinal electric field can increase the amplitude of the oscillations and this result is of practical and broad interest for both, experimental and device physics.

  17. Multi-orbits observed in superconducting Nb-doped Bi2Se3

    NASA Astrophysics Data System (ADS)

    Lawson, Benjamin; Corbae, Paul; Li, Gang; Yu, Fan; Asaba, Tomoya; Tinsman, Colin; Qiu, Yunsheng; Hor, Yew San; Li, Lu

    Recently discovered superconducting niobium doped Bi2Se3 shows promise to realize new physical phenomenon including the coexistence of superconductivity and magnetic ordering and possibly topological superconductivity. To understand the new physics showcased in this system, a detailed knowledge of the electronic structure is needed. We present the first observation of quantum oscillations in the magnetization (the de Haas-van Alphen effect) of Nb-doped Bi2Se3. In the fully superconducting crystal, two distinct orbits are observed, in sharp contrast to Bi2Se3, Cu-doped Bi2Se3, and Sr-doped Bi2Se3. The multiple frequencies observed in our quantum oscillations, combined with our electrical transport studies, indicate the multi-orbit nature of the electronic state of Nb-doped Bi2Se3.

  18. Quasi-two-dimensional Fermi surfaces of the heavy-fermion superconductor Ce2PdIn8

    NASA Astrophysics Data System (ADS)

    Götze, K.; Klotz, J.; Gnida, D.; Harima, H.; Aoki, D.; Demuer, A.; Elgazzar, S.; Wosnitza, J.; Kaczorowski, D.; Sheikin, I.

    2015-09-01

    We report low-temperature de Haas-van Alphen (dHvA) effect measurements in magnetic fields up to 35 T of the heavy-fermion superconductor Ce2PdIn8 . The comparison of the experimental results with band-structure calculations implies that the 4 f electrons are itinerant rather than localized. The cyclotron masses estimated at high field are only moderately enhanced, 8 m0 and 14 m0 , but are substantially larger than the corresponding band masses. The observed angular dependence of the dHvA frequencies suggests quasi-two-dimensional Fermi surfaces in agreement with band-structure calculations. However, the deviation from ideal two-dimensionality is larger than in CeCoIn5, to which Ce2PdIn8 bears a lot of similarities. This subtle distinction accounts for the different superconducting critical temperatures of the two compounds.

  19. Topological change of the Fermi surface in ternary iron-pnictides with reduced c/a ratio: A dHvA study of CaFe2P2

    SciTech Connect

    Coldea, Amalia I.; Andrew, C.M.J.; Analytis, J.G.; McDonald, R.D.; Bangura, A.F.; Chu, J.-H.; Fisher, I.R.; Carrington, A.; /Bristol U.

    2010-05-26

    We report a de Haas-van Alphen effect study of the Fermi surface of CaFe{sub 2}P{sub 2} using low temperature torque magnetometry up to 45 T. This system is a close structural analogue of the collapsed tetragonal non-magnetic phase of CaFe{sub 2}As{sub 2}. We find the Fermi surface of CaFe{sub 2}P{sub 2} to differ from other related ternary phosphides in that its topology is highly dispersive in the c-axis, being three-dimensional in character and with identical mass enhancement on both electron and hole pockets ({approx} 1.5). The dramatic change in topology of the Fermi surface suggests that in a state with reduced (c/a) ratio, when bonding between pnictogen layers becomes important, the Fermi surface sheets are unlikely to be nested.

  20. Iron-based superconductors in high magnetic fields

    NASA Astrophysics Data System (ADS)

    Coldea, Amalia I.; Braithwaite, Daniel; Carrington, Antony

    2013-01-01

    Here we review measurements of the normal and superconducting state properties of iron-based superconductors using high magnetic fields. We discuss the various physical mechanisms that limit superconductivity in high fields, and the information on the superconducting state that can be extracted from the upper critical field, but also how thermal fluctuations affect its determination by resistivity and specific heat measurements. We also discuss measurements of the normal state electronic structure focusing on measurement of quantum oscillations, particularly the de Haas-van Alphen effect. These results have determined very accurately, the topology of the Fermi surface and the quasi-particle masses in a number of different iron-based superconductors, from the 1111, 122 and 111 families.

  1. Concentration anomalies of the magnetization of HgSe:Fe crystals

    NASA Astrophysics Data System (ADS)

    Popenko, N.; Bekirov, B.; Ivanchenko, I.; Bludov, A.; Pashchenko, V.

    2014-10-01

    The field and temperature dependences of the magnetization of the semimagnetic semiconductor HgSe:Fe have been studied experimentally. The spin splitting of the Landau levels in the de Haas-van Alphen quantum oscillations has been recorded in the iron impurity concentration interval of 7 × 1018 cm-3 < N Fe < 2 × 1019 cm-3. The effective area of the extreme cross section of the Fermi surface has been determined from the obtained dependences of the oscillation period on the iron concentration, and the concentration of the collectivized electrons under conditions of the stabilization of the Fermi level on the iron donor level has been estimated. The critical impurity concentration at which the sharp increase in the Curie-Weiss temperature occurs owing to the spontaneous spin polarization of the system of hybridized electron states in iron-doped mercury selenide has been determined.

  2. New insights on frequency combinations and ‘forbidden frequencies’ in the de Haas–van Alphen spectrum of κ-(ET)2Cu(SCN)2

    NASA Astrophysics Data System (ADS)

    Audouard, Alain; Fortin, Jean-Yves; Vignolles, David; Laukhin, Vladimir N.; Kushch, Nataliya D.; Yagubskii, Eduard B.

    2016-07-01

    de Haas–van Alphen oscillations of the organic metal κ-(ET)2Cu(SCN)2 have been measured up to 55 T at liquid helium temperatures. The Fermi surface of this charge transfer salt is a textbook example of a linear chain of orbits coupled by magnetic breakdown. Accordingly, the oscillation spectrum is composed of linear combinations of the frequencies linked to the α and magnetic breakdown-induced β orbits. The field and temperature dependence of all the observed Fourier components, in particular the ‘forbidden frequency’ β -α which cannot correspond to a classical orbit, are quantitatively accounted for by analytical calculations based on a second order development of the free energy, i.e. beyond the first order Lifshitz–Kosevich formula.

  3. Measurements of the energy band gap and valence band structure of AgSbTe2

    NASA Astrophysics Data System (ADS)

    Jovovic, V.; Heremans, J. P.

    2008-06-01

    The de Haas-van Alphen effect, galvanomagnetic and thermomagnetic properties of high-quality crystals of AgSbTe2 are measured and analyzed. The transport properties reveal the material studied here to be a very narrow-gap semiconductor (Eg≈7.6±3meV) with ˜5×1019cm-3 holes in a valence band with a high density of states and thermally excited ˜1017cm-3 high-mobility (2200cm2/Vs) electrons at 300 K. The quantum oscillations are measured with the magnetic field oriented along the ⟨111⟩ axis. Taken together with the Fermi energy derived from the transport properties, the oscillations confirm the calculated valence band structure composed of 12 half-pockets located at the X -points of the Brillouin zone, six with a density-of-states effective mass mda∗≫0.21me and six with mdb∗≫0.55me , giving a total density-of-states effective mass, including Fermi pocket degeneracy, of md∗≈1.7±0.2me ( me is the free electron mass). The lattice term dominates the thermal conductivity, and the electronic contribution in samples with both electrons and holes present is in turn dominated by the ambipolar term. The low thermal conductivity and very large hole mass of AgSbTe2 make it a most promising p -type thermoelectric material.

  4. Anomalous behaviour of critical fields near a superconducting quantum critical point in BaFe2(As1-xPx)2

    NASA Astrophysics Data System (ADS)

    Putzke, C.; Carrington, A.; Walmsley, P.; Malone, L.; Fletcher, J. D.; See, P.; Vignolles, D.; Proust, C.; Badoux, S.; Kasahara, S.; Mazukami, Y.; Shibauchi, T.; Matsuda, Y.

    2014-03-01

    BaFe2(As1-xPx)2 presents one of the cleanest and clearest systems in which to study the influence of quantum critical fluctuations on high temperature superconductivity. In this material a sharp maximum in the magnetic penetration depth has been found at the quantum critical point (QCP x = 0 . 3) where Tc is maximal1. Specific heat and de Haas-van Alphen effect measurements2 show that this peak is driven by a corresponding increase in the quasiparticle effective mass. Based on these previous results a simple one-band theory would suggest that at the QCP we should expect a large increase in Hc 2 and a corresponding dip in Hc 1 . Actual measurements of these critical fields, which we present here, shows quite different behavior which we suggest is caused by an anomalous enhancement in the vortex core energy close to the QCP. 1 K.Hashimoto et.al., Science 336, 1554 (2012) 2 P.Walmsley, C.Putzke et.al., Phys. Rev. Lett. 110, 257002 (2013) This work was supported by the Engineering and Physical Sciences Research Council, EuroMagNET II, and KAKENHI from JSPS.

  5. Critical phenemona at the martensitic transition in the shape-memory alloy gold-zinc.

    NASA Astrophysics Data System (ADS)

    Lashley, Jason; Darling, Tim; Thoma, D. J.; Chu, Fuming; Migliori, Albert; Hults, W. L.; Lopez, Michael; Batista, Cristian; Smith, J. L.; Lang, Brian; Woodfield, Brian

    2002-03-01

    Since the discovery of the shape-memory effect, the martensitic transition has been described within the framework of classical equilibrium thermodynamics as a first-order displacive transition. However, as we investigate the physical properties (elastic moduli,specific heat, and stress/strain measurements) through the martensitic transition in AuZn at cryogenic temperatures, we find clear signatures of recoverable plastic strain and a second-order (continuous) transition at 64.7 K. It is argued that the combination of equiatomic composition (removing internal strains) and a low transition temperature (reducing both diffusion and entropy effects) constrain the chemical potential and its derivatives to exhibit behavior that lies at the borderline between that of a first-order (discontinuous) and a continuous phase transition. For these reasons, we propose a critical point in composition-temperature space located at mole fraction, x = 0.5 Zn and T approximately 65 K, connecting two coexistence lines of first-order martensitic phase transitions. Further support of the critical point is based on resistivitiy data of N. Ridley and H. Pops, Met. Trans. 1, 2867 (1970), cold-stage optical results of H. Pops and T. B. Massalski, Trans. AIME 233, 728 (1965), and de Haas-van Alphen measurements of A. Beck, J. P. Jan, W. B. Pearson, and I. M. Templeton, Phil. Mag. 8, 351 (1963).

  6. Recent developments in the determination of the amplitude and phase of quantum oscillations for the linear chain of coupled orbits

    NASA Astrophysics Data System (ADS)

    Audouard, Alain; Fortin, Jean-Yves

    2014-04-01

    De Haas-van Alphen oscillations are studied for Fermi surfaces (FS) illustrating the model proposed by Pippard in the early sixties, namely the linear chain of orbits coupled by magnetic breakdown. This FS topology is relevant to many multiband quasi-two-dimensional (q-2D) organic metals such as κ-(BEDT-TTF)2Cu(NCS)2 and θ-(BEDT-TTF)4CoBr4(C6H4Cl2) which are considered in detail. Whereas the Lifshits-Kosevich model only involves a first order development of field- and temperature-dependent damping factors, second order terms may have significant contribution to the Fourier components amplitude for such q-2D systems at high magnetic field and low temperature. The strength of these second order terms depends on the relative value of the involved damping factors, which are in turns strongly dependent on parameters such as the magnetic breakdown field, effective masses and, most of all, effective Lande factors. In addition, the influence of field-dependent Onsager phase factors on the oscillation spectra is considered.

  7. Quantum oscillations in iron-based superconductors: BaFe2As2 vs. KFe2As2

    NASA Astrophysics Data System (ADS)

    Terashima, Taichi; Kurita, Nobuyuki; Kimata, Motoi; Tomita, Megumi; Tsuchiya, Satoshi; Satsukawa, Hidetaka; Harada, Atsushi; Hazama, Kaori; Imai, Motoharu; Sato, Akira; Uji, Shinya; Kihou, Kunihiro; Lee, Chul-Ho; Kito, Hijiri; Tomioka, Yasuhide; Ito, Toshimitsu; Iyo, Akira; Eisaki, Hiroshi; Liang, Tian; Nakajima, Masamichi; Ishida, Shigeyuki; Uchida, Shin-ichi; Saito, Taku; Fukazawa, Hideto; Kohori, Yoh; Harima, Hisatomo

    2013-07-01

    We present results of Shubnikov-de Haas oscillation measurements on detwinned BaFe2As2 and de Haas-van Alphen oscillation measurements on KFe2As2. The Fermi surface of BaFe2As2 in the antiferromagnetic phase is found to consist of one hole and two electron pockets, all of which are three-dimensional and closed, and can reasonably be accounted for by LSD A band calculations. We find only moderate mass enhancements m*/mband of 2-3. In the case of KFe2As2, four quasi-two-dimensional Fermi surface cylinders epsilon, α, ζ, and β are observed in qualitative agreement with previous ARPES data. In sharp contrast to BaFe2As2, agreement between the observed and LDA-calculated Fermi surface is poor: LDA calculations seem to predict wrong crystal-field splitting of Fe 3d states. Large effective masses up to 20 me, me being the free electron mass, are found. The Sommerfeld coefficient estimated from the observed Fermi surface and effective masses is consistent with the measured value of 93 mJ/K2mol [H. Fukazawa et al., J. Phys. Soc. Jpn. 80, SA118 (2011)] and is 8-9 times larger than the band value, indicating strong electronic correlations in KFe2As2.

  8. Coexistence of Weyl physics and planar defects in the semimetals TaP and TaAs

    NASA Astrophysics Data System (ADS)

    Besara, T.; Rhodes, D. A.; Chen, K.-W.; Das, S.; Zhang, Q. R.; Sun, J.; Zeng, B.; Xin, Y.; Balicas, L.; Baumbach, R. E.; Manousakis, E.; Singh, D. J.; Siegrist, T.

    2016-06-01

    We report a structural study of the Weyl semimetals TaAs and TaP, utilizing diffraction and imaging techniques, where we show that they contain a high density of defects, leading to nonstoichiometric single crystals of both semimetals. Despite the observed defects and nonstoichiometry on samples grown using techniques already reported in the literature, de Haas-van Alphen measurements on TaP reveal quantum oscillations and a high carrier mobility, an indication that the crystals are of quality comparable to those reported elsewhere. Electronic structure calculations on TaAs reveal that the position of the Weyl points relative to the Fermi level shift with the introduction of vacancies and stacking faults. In the case of vacancies the Fermi surface becomes considerably altered, while the effect of stacking faults on the electronic structure is to allow the Weyl pockets to remain close to the Fermi surface. The observation of quantum oscillations in a nonstoichiometric crystal and the persistence of Weyl fermion pockets near the Fermi surface in a crystal with stacking faults point to the robustness of these quantum phenomena in these materials.

  9. Spin-zero anomaly in the magnetic quantum oscillations of a two-dimensional metal.

    SciTech Connect

    Wosnitza, J.; Gvozdikov, V. M.; Hagel, J.; Meeson, P. J.; Schlueter, J. A.; Ignatchick, O.; Winter, R. W.; Gard, G. L.; Davis, H.; Bergk, B.; Materials Science Division; Technische Univ. Dresden; Max-Planck Inst. Phys. Complex Systems; Univ. Bristol; Portland State Univ.

    2008-01-01

    We report on an anomalous behavior of the spin-splitting zeros in the de Haas-van Alphen (dHvA) signal of a quasi-two-dimensional organic superconductor. The zeros as well as the angular dependence of the amplitude of the second harmonic deviate remarkably from the standard Lifshitz-Kosevich (LK) prediction. In contrast, the angular dependence of the fundamental dHvA amplitude as well as the spin-splitting zeros of the Shubnikov-de Haas (SdH) signal follow the LK theory. We can explain this behavior of the dHvA signal by small chemical-potential (CP) oscillations and find a very good agreement between theory and experiment. A detailed wave-shape analysis of the dHvA oscillations corroborates the existence of an oscillating CP. We discuss the absence of the above spin-zero effect in the SdH signal and argue that in {beta}{double_prime}-(BEDT-TTF){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} it can be explained by an incoherent variable range hopping interlayer transport which is insensitive to the small CP oscillations.

  10. Multiple Fermi surfaces in superconducting Nb-doped Bi2Se3

    NASA Astrophysics Data System (ADS)

    Lawson, B. J.; Corbae, Paul; Li, Gang; Yu, Fan; Asaba, Tomoya; Tinsman, Colin; Qiu, Y.; Medvedeva, J. E.; Hor, Y. S.; Li, Lu

    2016-07-01

    Topological insulator Bi2Se3 has shown a number of interesting physical properties. Doping Bi2Se3 with copper or strontium has been demonstrated to make the material superconducting and potentially even a topological superconductor. The recent discovery of superconducting niobium-doped Bi2Se3 reveals an exciting new physical phenomenon, the coexistence of superconductivity and magnetic ordering, as well as signatures of an odd-parity p -wave superconducting order. To understand this new phenomenon, a detailed knowledge of the electronic structure is needed. We present an observation of quantum oscillations in the magnetization (the de Haas-van Alphen effect) of Nb-doped Bi2Se3 . In the fully superconducting crystal, two distinct orbits are observed, in sharp contrast to Bi2Se3 , Cu-doped Bi2Se3 , and Sr-doped Bi2Se3 . The multiple frequencies observed in our quantum oscillations, combined with our electrical transport studies, indicate the multi-orbit nature of the electronic state of Nb-doped Bi2Se3 .

  11. Two-dimensional Fermi surfaces in Kondo insulating SmB6

    NASA Astrophysics Data System (ADS)

    Li, Gang

    There has been renewed interest in Samarium Hexaboride, which is a strongly correlated heavy Fermion material. Hybridization between itinerant electrons and localized orbitals lead to an opening of charge gap at low temperature. However, the resistivity of SmB6 does not diverge at low temperature. Former studies suggested that this residual conductance is contributed by various origins. Recent theoretical developments suggest that the particular symmetry of energy bands of SmB6 may host a topologically non-trivial surface state, i.e., a topological Kondo insulator. To probe the Fermiology of the possible metallic surface state, we use sensitive torque magnetometry to detect the de Haas van Alphen (dHvA) effect due to Landau level quantization on flux-grown crystals, down to He-3 temperature and up to 45 Tesla. Our angular and temperature dependent data suggest two-dimensional Fermi Surfaces lie in both crystalline (001) and (101) surface planes of SmB6.

  12. Neutrality of a magnetized two-flavor quark superconductor

    NASA Astrophysics Data System (ADS)

    Mandal, Tanumoy; Jaikumar, Prashanth

    2013-04-01

    We investigate the effect of electric and color charge neutrality on the two-flavor color superconducting (2SC) phase of cold and dense quark matter in presence of constant external magnetic fields and at moderate baryon densities. Within the framework of the Nambu-Jona-Lasinio (NJL) model, we study the interdependent evolution of the quark's BCS gap and constituent mass with increasing density and magnetic field. While confirming previous results derived for the highly magnetized 2SC phase with color neutrality alone, we obtain new results as a consequence of imposing charge neutrality. In the charge neutral gapless 2SC phase (g2SC), a large magnetic field drives the color superconducting phase transition to a crossover, while the chiral phase transition is first order. At larger diquark-to-scalar coupling ratio GD/GS, where the 2SC phase is preferred, we see hints of the Clogston-Chandrasekhar limit at a very large value of the magnetic field (B˜1019G), but this limit is strongly affected by Shubnikov de Haas-van Alphen oscillations of the gap, indicating the transition to a domain-like state.

  13. Pressure dependence of the Fermi surface of hcp Yb

    NASA Astrophysics Data System (ADS)

    Schirber, J. E.; Beaudry, B. J.; Jepsen, O.

    1981-06-01

    The pressure dependence of Fermi-surface cross sections for principal symmetry directions has been investigated using solid He pressure generation techniques. Careful searches for de Haas-van Alphen signals were conducted from 2 to 9 kbar in both virgin fcc crystals and samples transformed from hcp to fcc. No sign of the frequency reported by Ribault was detected. Results are discussed in terms of theoretically calculated pressure-induced changes in the band structure and Fermi surface of the hcp phase of Yb.

  14. Anomalous hysteresis as evidence for a magnetic-field-induced chiral superconducting state in LiFeAs

    NASA Astrophysics Data System (ADS)

    Li, G.; Urbano, R. R.; Goswami, P.; Tarantini, C.; Lv, B.; Kuhns, P.; Reyes, A. P.; Chu, C. W.; Balicas, L.

    2013-01-01

    Magnetometry measurements in high-quality LiFeAs single crystals reveal a change in the sign of the magnetic hysteresis in the vicinity of the upper critical field Hc2, from a clear diamagnetic response dominated by the pinning of vortices to a considerably smaller net hysteretic response of opposite sign, which disappears at Hc2. If the diamagnetic response at high fields results from pinned vortices and associated screening supercurrents, this sign change must result from currents circulating in the opposite sense, which give rise to a small field-dependent magnetic moment below Hc2. This behavior seems to be extremely sensitive to the sample quality or stoichiometry, as we have observed it only in a few fresh crystals, which also display the de Haas van Alphen effect. We provide arguments against the surface superconductivity, the flux compression, and the random π junction scenarios, which have been previously put forward to explain a paramagnetic Meissner effect, below the lower critical field Hc1. The observed anomalous hysteresis at high fields will be compatible with the existence of chiral gap wave functions, which possess a field-dependent magnetic moment. Within a Landau-Ginzburg framework, we demonstrate how a (dx2-y2+idxy) or a (px+ipy) chiral superconducting component can be stabilized in the mixed state of s± superconductor, due to the combined effects of the magnetic field and the presence of competing pairing channels. The realization of a particular chiral pairing depends on the microscopic details of the strengths of the competing pairing channels.

  15. Superconducting properties of K1-xNaxFe2As2 under pressure

    NASA Astrophysics Data System (ADS)

    Grinenko, V.; Schottenhamel, W.; Wolter, A. U. B.; Efremov, D. V.; Drechsler, S.-L.; Aswartham, S.; Kumar, M.; Wurmehl, S.; Roslova, M.; Morozov, I. V.; Holzapfel, B.; Büchner, B.; Ahrens, E.; Troyanov, S. I.; Köhler, S.; Gati, E.; Knöner, S.; Hoang, N. H.; Lang, M.; Ricci, F.; Profeta, G.

    2014-09-01

    The effects of hydrostatic pressure and partial Na substitution on the normal-state properties and the superconducting transition temperature (Tc) of K1-xNaxFe2As2 single crystals were investigated. It was found that a partial Na substitution leads to a deviation from the standard T2 Fermi-liquid behavior in the temperature dependence of the normal-state resistivity. It was demonstrated that non-Fermi-liquid like behavior of the resistivity for K1-xNaxFe2As2 and some KFe2As2 samples can be explained by a disorder effect in the multiband system with rather different quasiparticle effective masses. Concerning the superconducting state our data support the presence of a shallow minimum around 2 GPa in the pressure dependence of Tc for stoichiometric KFe2As2. The analysis of Tc in K1-xNaxFe2As2 at pressures below 1.5 GPa showed that the reduction of Tc with Na substitution follows the Abrikosov-Gor'kov law with the critical temperature Tc0 of the clean system (without pair breaking), which linearly depends on the pressure. Our observations also suggest that Tc of K1-xNaxFe2As2 is nearly independent of the lattice compression produced by the Na substitution. Further, we theoretically analyzed the behavior of the band structure under pressure within the generalized gradient approximation (GGA). A qualitative agreement between the calculated and the recently measured—in de Haas-van Alphen experiments [T. Terashima et al., Phys. Rev. B 89, 134520 (2014), 10.1103/PhysRevB.89.134520]—pressure dependencies of the Fermi-surface cross sections has been found. These calculations also indicate that the observed minimum around 2 GPa in the pressure dependence of Tc may occur without a change of the pairing symmetry.

  16. Large Cyclotron Mass and Large Ordered Moment in Ferromagnet CoS2 Compared with Paramagnet CoSe2

    NASA Astrophysics Data System (ADS)

    Teruya, Atsushi; Suzuki, Fuminori; Aoki, Dai; Honda, Fuminori; Nakamura, Ai; Nakashima, Miho; Amako, Yasushi; Harima, Hisatomo; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika

    2016-06-01

    We succeeded in growing high-quality single crystals of the pyrite-type cubic compounds CoSe2 and CoS2 using the transport agent CoBr2 and measured the electrical resistivity, specific heat, magnetic susceptibility, magnetization, and de Haas-van Alphen (dHvA) effect. We confirmed that CoSe2 is an exchange-enhanced paramagnet revealing a broad maximum at around 50 K in the temperature dependence of the magnetic susceptibility. The electronic specific heat coefficient is moderately large, γ = 18 mJ/(K2·mol). On the other hand, CoS2 is a ferromagnet with a Curie temperature TC = 122 K and an ordered moment μs = 0.93 μB/Co. The γ of 21 mJ/(K2·mol) of CoS2 is slightly larger than that of CoSe2. A large ordered moment, together with a large γ, is characteristic of CoS2 because CoS2 is a half-metallic spin state in the ferromagnetic state. Correspondingly, we detected a main dHvA branch with a large cyclotron effective mass of 13m0 in the dHvA experiments. The detected dHvA branches in CoS2 and CoSe2 are discussed on the basis of the results of energy band calculations, revealing a broken fourfold symmetry in the angular dependence of the dHvA frequency.

  17. Magnetic and Fermi Surface Properties of EuGa4

    NASA Astrophysics Data System (ADS)

    Nakamura, Ai; Hiranaka, Yuichi; Hedo, Masato; Nakama, Takao; Miura, Yasunao; Tsutsumi, Hiroki; Mori, Akinobu; Ishida, Kazuhiro; Mitamura, Katsuya; Hirose, Yusuke; Sugiyama, Kiyohiro; Honda, Fuminori; Settai, Rikio; Takeuchi, Tetsuya; Hagiwara, Masayuki; Matsuda, Tatsuma D.; Yamamoto, Etsuji; Haga, Yoshinori; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Harima, Hisatomo; Ōnuki, Yoshichika

    2013-10-01

    We grew a high-quality single crystal EuGa4 with the tetragonal structure by the Ga self-flux method, and measured the electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat, thermoelectric power and de Haas--van Alphen (dHvA) effect, together with the electrical resistivity and thermoelectric power under pressure. EuGa4 is found to be a Eu-divalent compound without anisotropy of the magnetic susceptibility in the paramagnetic state and to reveal the same magnetization curve between H \\parallel [100] and [001] in the antiferromagnetic state, where the antiferromagnetic easy-axis is oriented along the [100] direction below a Néel temperature TN=16.5 K. The magnetization curve is discussed on the basis of a simple two-sublattice model. The Fermi surface in the paramagnetic state was clarified from the results of a dHvA experiment for EuGa4 and an energy band calculation for a non-4f reference compound SrGa4, which consists of a small ellipsoidal hole--Fermi surface and a compensated cube-like electron--Fermi surface with vacant space in center. We observed an anomaly in the temperature dependence of the electrical resistivity and thermoelectric power at TCDW=150 K under 2 GPa. This might correspond to an emergence of the charge density wave (CDW). The similar phenomenon was also observed in EuAl4 at ambient pressure. We discussed the CDW phenomenon on the basis of the present peculiar Fermi surfaces.

  18. Anisotropic hydrodynamics, bulk viscosities, and r-modes of strange quark stars with strong magnetic fields

    SciTech Connect

    Huang Xuguang; Huang Mei; Rischke, Dirk H.; Sedrakian, Armen

    2010-02-15

    In strong magnetic fields the transport coefficients of strange quark matter become anisotropic. We determine the general form of the complete set of transport coefficients in the presence of a strong magnetic field. By using a local linear response method, we calculate explicitly the bulk viscosities {zeta}{sub perpendicular} and {zeta}{sub ||} transverse and parallel to the B field, respectively, which arise due to the nonleptonic weak processes u+s{r_reversible}u+d. We find that for magnetic fields B<10{sup 17} G, the dependence of {zeta}{sub perpendicular} and {zeta}{sub ||} on the field is weak, and they can be approximated by the bulk viscosity for the zero magnetic field. For fields B>10{sup 18} G, the dependence of both {zeta}{sub perpendicular} and {zeta}{sub ||} on the field is strong, and they exhibit de Haas-van Alphen-type oscillations. With increasing magnetic field, the amplitude of these oscillations increases, which eventually leads to negative {zeta}{sub perpendicular} in some regions of parameter space. We show that the change of sign of {zeta}{sub perpendicular} signals a hydrodynamic instability. As an application, we discuss the effects of the new bulk viscosities on the r-mode instability in rotating strange quark stars. We find that the instability region in strange quark stars is affected when the magnetic fields exceed the value B=10{sup 17} G. For fields which are larger by an order of magnitude, the instability region is significantly enlarged, making magnetized strange stars more susceptible to r-mode instability than their unmagnetized counterparts.

  19. Low Temperature Physics at Yale in the late 30's through the early 50's

    NASA Astrophysics Data System (ADS)

    Wheeler, Robert

    2006-03-01

    The low temperature program at Yale was initiated by C. T. Lane (1904-1991) in the fall of 1937 when he was appointed to the teaching staff as an instructor in the department of Physics. Following his doctorate from McGill in 1929 he investigated the magnetic susceptibilities of ``soft'' metals supported by the National Research Council of Canada, the Commissioners of the 1851 Exhibition and a Sterling Fellowship at Yale. Arranged by Louis McKeehan, with 5000 from the new George Sheffield research fund, he started the construction of a Kapitza type helium liquefier. The machine was largely completed in the fall of 1939, yet liquid helium was not made until early December 1940 due to the need for extensive on line purification of the gas. Returning in 1945 from war research, Lane and Henry A. Fairbank (Ph.D 1944) continued the metals work along with new thrusts into Second Sound , properties of helium^ three impurities in liquid helium and starting in the 50's on rotating He II. In 1933 both Lane and Onsager were awarded Sterling Fellowships, which initiated a stimulating experimental- theoretical exchange continuing until they both retired. The best-known example was the rediscovery at Yale of the deHaas-van Alphen effect, previously observed only in bismuth, in zinc; where upon Onsager and his students provided new insights into our understanding of the Fermi surface of metals. With the development of new instrumentation one observed vast changes in experimental style during this period. The evolution of the production of liquid helium from Lane's device though the Collins machine to the commodity business of today now makes experiments of huge size and importance possible.

  20. Entropy and Fermi surface considerations in the nematic phase of Sr3Ru2O7

    NASA Astrophysics Data System (ADS)

    MacKenzie, Andrew

    2010-03-01

    The layered perovskite metal Sr3Ru2O7 has generated interest because of the discovery of nematic-like electrical transport properties at low temperatures [1]. The unusual properties are seen in the vicinity of a metamagnetic quantum critical point. They appear to be the result of the formation of a new phase, which can be observed only in the highest purity single crystals, with mean free paths of several thousand angstroms. Recently, my group has concentrated on understanding this phase and determining its boundaries using thermodynamic probes. In this talk I will review the physics that we believe underlies our observations, and then report on the recent progress, showing how measurements of the specific heat and magneto-caloric effect enable the determination of a complete ``entropy landscape'' of phase formation in the vicinity of a quantum critical point [2]. I will also discuss the discovery of de Haas-van Alphen oscillations within the putative electronic nematic phase [3]. [4pt] [1] R.A. Borzi, S.A. Grigera, J. Farrell, R.S. Perry, S. Lister, S.L. Lee, D.A. Tennant, Y. Maeno & A.P. Mackenzie, Science 315, 214 (2007). [0pt] [2] A.W. Rost, R.S. Perry, J.F. Mercure, A.P. Mackenzie & S.A. Grigera, Science 325, 1360 (2009). [0pt] [3] J.-F. Mercure, S. K. Goh, E. C. T. O'Farrell, R. S. Perry, M. L. Sutherland, A. Rost, S. A. Grigera, R. A. Borzi, P. Gegenwart and A. P. Mackenzie, Phys. Rev. Lett. 103, 176401 (2009).

  1. Normal-state and superconducting properties of Sr{sub 2}RuO{sub 4}

    SciTech Connect

    Maeno, Y.; Nishizaki, S.; Yoshida, K.

    1996-12-01

    The authors discuss some of the current issues on the copper-free layered perovskite superconductor Sr{sub 2}RuO{sub 4}, for which a sharp transition at T{sub c} = 1.2 K has been reproducibly obtained. The normal state is characterized as an essentially two-dimensional Fermi liquid, and the coherent interlayer transport is established only at low temperatures. The cylindrical Fermi surface observed by de Haas-van Alphen experiments is consistent with other thermodynamic and transport properties. Although the specific heat jump across T{sub c} confirms the bulk superconductivity, the large residual T-linear term which correlates with the variation in T{sub c} is unusual and suggestive of unconventional pairing.

  2. Thermoelectric power quantum oscillations in the ferromagnet UGe2

    NASA Astrophysics Data System (ADS)

    Palacio Morales, A.; Pourret, A.; Knebel, G.; Bastien, G.; Taufour, V.; Aoki, D.; Yamagami, H.; Flouquet, J.

    2016-04-01

    We present thermoelectric power and resistivity measurements in the ferromagnet UGe2 as a function of temperature and magnetic field. At low temperature, huge quantum oscillations are observed in the thermoelectric power as a function of the magnetic field applied along the a axis. The frequencies of the extreme orbits are determined and an analysis of the cyclotron masses is performed following different theoretical approaches for quantum oscillations detected in the thermoelectric power. They are compared to those obtained by Shubnikov-de Haas experiments on the same crystal and previous de Haas-van Alphen experiments. The agreement of the different probes confirms thermoelectric power as an excellent probe to extract simultaneously both microscopic and macroscopic information on the Fermi surface properties. Band structure calculations of UGe2 in the ferromagnetic state are compared to the experiment.

  3. Landau quantization and spin-momentum locking in topological Kondo insulators

    NASA Astrophysics Data System (ADS)

    Schlottmann, P.

    2016-05-01

    SmB6 has been predicted to be a strong topological Kondo insulator and experimentally it has been confirmed that at low temperatures the electrical conductivity only takes place at the surfaces of the crystal. Quantum oscillations and ARPES measurements revealed several Dirac cones on the (001) and (101) surfaces of the crystal. We considered three types of surface Dirac cones with an additional parabolic dispersion and studied their Landau quantization and the expectation value of the spin of the electrons. The Landau quantization is quite similar in all three cases and would give rise to very similar de Haas-van Alphen oscillations. The spin-momentum locking, on the other hand, differs dramatically. Without the additional parabolic dispersion the spins are locked in the plane of the surface. The parabolic dispersion, however, produces a gradual canting of the spins out of the surface plane.

  4. Split Fermi Surface Properties in Ullmannite NiSbS and PdBiSe with the Cubic Chiral Crystal Structure

    NASA Astrophysics Data System (ADS)

    Kakihana, Masashi; Teruya, Atsushi; Nishimura, Kengo; Nakamura, Ai; Takeuchi, Tetsuya; Haga, Yoshinori; Harima, Hisatomo; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika

    2015-09-01

    We grew single crystals of ullmannite NiSbS and PbBiSe with the cubic chiral structure and carried out electrical resistivity, specific heat, and de Haas-van Alphen (dHvA) experiments to clarify their Fermi surface properties. The Fermi surfaces were found to split into two, reflecting the non-centrosymmetric crystal structure. The splitting energies between the two nearly spherical electron Fermi surfaces named α and α' were determined as 220 K in NiSbS and 1050 K in PdBiSe for H || [100] or [001]. This difference in splitting energies between the two compounds originates mainly from the fact that the spin-orbit interactions of Ni-3d, Sb-5p, and S-3p electrons in NiSbS are smaller in magnitude than those of Pd-4d, Bi-6p, and Se-4p electrons in PdBiSe, respectively.

  5. A brief update of angle-resolved photoemission spectroscopy on a correlated electron system

    SciTech Connect

    Lee, W.S.

    2010-02-24

    In this paper, we briefly summarize the capabilities of state-of-the-art angle-resolved photoemission spectroscopy (ARPES) in the field of experimental condensed matter physics. Due to the advancement of the detector technology and the high flux light sources, ARPES has become a powerful tool to study the low energy excitations of solids, especially those novel quantum materials in which many-body physics are at play. To benchmark today's state-of-the-art ARPES technique, we demonstrate that the precision of today's ARPES has advanced to a regime comparable to the bulk-sensitive de Haas-van Alphen (dHvA) measurements. Finally, as an example of new discoveries driven by the advancement of the ARPES technique, we summarize some of our recent ARPES measurements on underdoped high-T{sub c} superconducting cuprates, which have provided further insight into the complex pseudogap problem.

  6. Field-Induced Metal-Insulator Transition in a Two-Dimensional Organic Superconductor

    SciTech Connect

    Wosnitza, J.; Wanka, S.; Hagel, J.; Lo''hneysen, H. v.; Qualls, J. S.; Brooks, J. S.; Balthes, E.; Schlueter, J. A.; Geiser, U.; Mohtasham, J.

    2001-01-15

    The quasi-two-dimensional organic superconductor {beta}''-( BEDT-TTF){sub 2}SF{sub 5} CH{sub 2}CF {sub 2}SO{sub 3} (T{sub c}{approx}4.4 K) shows very strong Shubnikov--de Haas (SdH) oscillations which are superimposed on a highly anomalous steady background magnetoresistance, R{sub b} . Comparison with de Haas--van Alphen oscillations allows a reliable estimate of R{sub b} which is crucial for the correct extraction of the SdH signal. At low temperatures and high magnetic fields insulating behavior evolves. The magnetoresistance data violate Kohler's rule, i.e., cannot be described within the framework of semiclassical transport theory, but converge onto a universal curve appropriate for dynamical scaling at a metal-insulator transition.

  7. Crossover between two-dimensional surface state and three-dimensional bulk phase in Fe-doped Bi2Te3

    NASA Astrophysics Data System (ADS)

    Jo, Na Hyun; Lee, Kyujoon; Kim, Jinsu; Jang, Jungwon; Kim, Jinhee; Jung, Myung-Hwa

    2014-06-01

    In Fe-doped Bi2Te3, we have observed higher mobility, larger linear magnetoresistance, and anomalous quantum oscillations. The angle dependence of Shubnikov-de Haas (SdH) oscillations gives two different periodicities depending on the angle from the c-axis. The low-angle SdH period is identified with a surface origin, while the high-angle period is against the surface origin. The high-angle SdH period well agrees with the de Haas-van Alphen (dHvA) period with a bulk origin. The physical parameters obtained from the quantum oscillations support the crossover between two-dimensional surface state and three-dimensional bulk phase by Fe doping in Bi2Te3.

  8. First-principle calculations of the Berry curvature of Bloch states for charge and spin transport of electrons.

    PubMed

    Gradhand, M; Fedorov, D V; Pientka, F; Zahn, P; Mertig, I; Györffy, B L

    2012-05-30

    Recent progress in wave packet dynamics based on the insight of Berry pertaining to adiabatic evolution of quantum systems has led to the need for a new property of a Bloch state, the Berry curvature, to be calculated from first principles. We report here on the response to this challenge by the ab initio community during the past decade. First we give a tutorial introduction of the conceptual developments we mentioned above. Then we describe four methodologies which have been developed for first-principle calculations of the Berry curvature. Finally, to illustrate the significance of the new developments, we report some results of calculations of interesting physical properties such as the anomalous and spin Hall conductivity as well as the anomalous Nernst conductivity and discuss the influence of the Berry curvature on the de Haas-van Alphen oscillation. PMID:22575767

  9. Phase diagram of CeRh2Si2 under pressure studied by thermopower measurements

    NASA Astrophysics Data System (ADS)

    Palacio-Morales, A.; Pourret, A.; Knebel, G.; Aoki, D.; Braithwaite; Flouquet, J.

    2015-03-01

    We report the evolution of thermoelectric power under hydrostatic pressure up to 17 kbar and at low temperature in the heavy fermion compound CeRh2Si2. These measurements were performed using a thermoelectric setup specially designed for piston cylinder pressure cells. The suppression of the antiferromagnetic order (AF) into a paramagnetic order (PM) state was studied and the (T, P) phase diagram was precisely obtained. The different magnetic transitions at low temperature as a function of pressure, AF1-AF2 transition at P'c and AF1-PM transition at Pc, show significant changes in the thermoelectric signal. This support reconstructions of the Fermi surface in agreement with previous de Haas van Alphen experiments.

  10. Specific features of quantum oscillations of magnetization in quasi-two-dimensional antiferromagnetic semimetals

    NASA Astrophysics Data System (ADS)

    Dzebisashvili, D. M.; Khudaiberdyev, A. A.

    2016-06-01

    The specific features of quantum oscillations of the magnetization in quasi-two-dimensional wide-band-gap antiferromagnetic semimetals with a low concentration of charge carriers have been considered theoretically. It has been shown that, in these systems, the Fermi energy determined from the analysis of the frequency of the de Haas-van Alphen oscillations according to the standard procedure can differ significantly from the true value. For the correct determination of the Fermi energy in the canted phase, it has been proposed to analyze quantum oscillations of the magnetization M not as a function of the inverse magnetic field 1/ H, but as a function of 1/cosγ, where the angle γ characterizes the inclination angle of the magnetic field with respect to the plane of the quasi-two-dimensional semimetal.

  11. Crossover between two-dimensional surface state and three-dimensional bulk phase in Fe-doped Bi{sub 2}Te{sub 3}

    SciTech Connect

    Jo, Na Hyun; Lee, Kyujoon; Jung, Myung-Hwa; Kim, Jinsu; Jang, Jungwon; Kim, Jinhee

    2014-06-23

    In Fe-doped Bi{sub 2}Te{sub 3}, we have observed higher mobility, larger linear magnetoresistance, and anomalous quantum oscillations. The angle dependence of Shubnikov-de Haas (SdH) oscillations gives two different periodicities depending on the angle from the c-axis. The low-angle SdH period is identified with a surface origin, while the high-angle period is against the surface origin. The high-angle SdH period well agrees with the de Haas-van Alphen (dHvA) period with a bulk origin. The physical parameters obtained from the quantum oscillations support the crossover between two-dimensional surface state and three-dimensional bulk phase by Fe doping in Bi{sub 2}Te{sub 3}.

  12. Hole Fermi surface in Bi2Se3 probed by quantum oscillations

    NASA Astrophysics Data System (ADS)

    Piot, B. A.; Desrat, W.; Maude, D. K.; Orlita, M.; Potemski, M.; Martinez, G.; Hor, Y. S.

    2016-04-01

    Transport and torque magnetometry measurements are performed at high magnetic fields and low temperatures in a series of p-type (Ca-doped) Bi2Se3 crystals. The angular dependence of the Shubnikov-de Haas and de Haas-van Alphen quantum oscillations enables us to determine the Fermi surface of the bulk valence band states as a function of the carrier density. At low density, the angular dependence exhibits a downturn in the oscillations frequency between 0∘ and 90∘, reflecting a bag-shaped hole Fermi surface. The detection of a single frequency for all tilt angles rules out the existence of a Fermi surface with different extremal cross sections down to 24 meV. There is therefore no signature of a camelback in the valence band of our bulk samples, in accordance with the direct band gap predicted by G W calculations.

  13. Fermi Surface and Van Hove Singularities in the Itinerant Metamagnet Sr(3)Ru(2)O(7)

    SciTech Connect

    Tamai, A.; Allan, M.P.; Mercure, J.F.; Meevasana, W.; Dunkel, R.; Lu, D.H.; Perry, R.S.; Mackenzie, A.P.; Singh, D.J.; Shen, Z.-X.; Baumberger, F.; /Scottish U. Research Reactor Ctr. /St. Andrews U.

    2011-01-04

    The low-energy electronic structure of the itinerant metamagnet Sr{sub 3}Ru{sub 2}O{sub 7} is investigated by angle resolved photoemission and density functional calculations. We find well-defined quasiparticle bands with resolution limited line widths and Fermi velocities up to an order of magnitude lower than in single layer Sr{sub 2}RuO{sub 4}. The complete topography, the cyclotron masses and the orbital character of the Fermi surface are determined, in agreement with bulk sensitive de Haas - van Alphen measurements. An analysis of the dxy band dispersion reveals a complex density of states with van Hove singularities (vHs) near the Fermi level; a situation which is favorable for magnetic instabilities.

  14. Organic Superconductors

    SciTech Connect

    Charles Mielke

    2009-02-27

    Intense magnetic fields are an essential tool for understanding layered superconductors. Fundamental electronic properties of organic superconductors are revealed in intense (60 tesla) magnetic fields. Properties such as the topology of the Fermi surface and the nature of the superconducting order parameter are revealed. With modest maximum critical temperatures~13K the charge transfer salt organic superconductors prove to be incredibly valuable materials as their electronically clean nature and layered (highly anisotropic) structures yield insights to the high temperature superconductors. Observation of de Haas-van Alphen and Shubnikov-de Haas quantum oscillatory phenomena, magnetic field induced superconductivity and re-entrant superconductivity are some of the physical phenomena observed in the charge transfer organic superconductors. In this talk, I will discuss the nature of organic superconductors and give an overview of the generation of intense magnetic fields; from the 60 tesla millisecond duration to the extreme 1000 tesla microsecond pulsed magnetic fields.

  15. Determination of surface structure of cleaved (001) USb2 single crystal

    SciTech Connect

    Chen, Shao-ping; Hawley, Marilyn; Bauer, Eric D; Stockum, Phil B; Manoharan, Hari C

    2009-01-01

    ), and the presence of contaminants, all of which are averaged over when probed in photoemission studies. The quasi two-dimensional USb{sub 2} has a layered tetragonal structure that is easily cleaved and has been extensively studied by a number of different techniques, such as resistivity, Hall effect measurements, photoemission and angle-resolved photoemission spectroscopy, de Haas-van Alphen, neutron diffraction, nuclear magnetic resonance, and U{sup 238} Mossbauer spectroscopy techniques. Here, we provide local information about the surfaces of this interesting compound, which we find to contain a high density of defects.

  16. Structure of cleaved (001) USb2 single crystal

    SciTech Connect

    Chen, Shao-ping; Hawley, Marilyn; Bauer, Eric D; Stockum, Phil B; Manoharan, Hari C

    2009-01-01

    , all of which are averaged over when probed in photoemission studies. The quasi two-dimensional USb{sub 2} has a layered tetragonal structure that is easily cleaved and has been extensively studied by a number of different techniques, such as resistivity, Hall effect measurements, photoemission and angle-resolved photoemission spectroscopy, de Haas-van Alphen, neutron diffraction, nuclear magnetic resonance, and U{sup 238} Mossbauer spectroscopy techniques. Here, we provide local information about the surfaces of this interesting compound, which we find to contain a high density of defects.

  17. Oscillating magnetocaloric effect in size-quantized diamagnetic film

    SciTech Connect

    Alisultanov, Z. Z.

    2014-03-21

    We investigate the oscillating magnetocaloric effect on a size-quantized diamagnetic film in a transverse magnetic field. We obtain the analytical expression for the thermodynamic potential in case of the arbitrary spectrum of carriers. The entropy change is shown to be the oscillating function of the magnetic field and the film thickness. The nature of this effect is the same as for the de Haas–van Alphen effect. The magnetic part of entropy has a maximal value at some temperature. Such behavior of the entropy is not observed in magneto-ordered materials. We discuss the nature of unusual behavior of the magnetic entropy. We compare our results with the data obtained for 2D and 3D cases.

  18. Zeeman effect of the topological surface states revealed by quantum oscillations up to 91 Tesla

    NASA Astrophysics Data System (ADS)

    Zhang, Zuocheng; Wei, Wei; Yang, Fangyuan; Zhu, Zengwei; Guo, Minghua; Feng, Yang; Yu, Dejing; Yao, Mengyu; Harrison, Neil; McDonald, Ross; Zhang, Yuanbo; Guan, Dandan; Qian, Dong; Jia, Jinfeng; Wang, Yayu

    2015-12-01

    We report quantum oscillation studies on the B i2T e3 -xSx topological insulator single crystals in pulsed magnetic fields up to 91 T. For the x =0.4 sample with the lowest bulk carrier density, the surface and bulk quantum oscillations can be disentangled by combined Shubnikov-de Haas and de Hass-van Alphen oscillations, as well as quantum oscillations in nanometer-thick peeled crystals. At high magnetic fields beyond the bulk quantum limit, our results suggest that the zeroth Landau level of topological surface states is shifted due to the Zeeman effect. The g factor of the topological surface states is estimated to be between 1.8 and 4.5. These observations shed new light on the quantum transport phenomena of topological insulators in ultrahigh magnetic fields.

  19. Evidence of Topological Nodal-Line Fermions in ZrSiSe and ZrSiTe

    NASA Astrophysics Data System (ADS)

    Hu, Jin; Tang, Zhijie; Liu, Jinyu; Liu, Xue; Zhu, Yanglin; Graf, David; Myhro, Kevin; Tran, Son; Lau, Chun Ning; Wei, Jiang; Mao, Zhiqiang

    2016-07-01

    A Dirac nodal-line semimetal phase, which represents a new quantum state of topological materials, has been experimentally realized only in a few systems, including PbTaSe2 , PtSn4 , and ZrSiS. In this Letter, we report evidence of nodal-line fermions in ZrSiSe and ZrSiTe probed in de Haas-van Alphen quantum oscillations. Although ZrSiSe and ZrSiTe share a similar layered structure with ZrSiS, our studies show the Fermi surface (FS) enclosing a Dirac nodal line has a 2D character in ZrSiTe, in contrast with 3D-like FS in ZrSiSe and ZrSiS. Another important property revealed in our experiment is that the nodal-line fermion density in this family of materials (˜1020 cm-3 ) is much higher than the Dirac fermion density of other topological materials with discrete nodes. In addition, we have demonstrated ZrSiSe and ZrSiTe single crystals can be thinned down to 2D atomic thin layers through microexfoliation, which offers the first platform to explore exotic properties of topological nodal-line fermions in low dimensions.

  20. Unusual magnetic quantum oscillations in organic metals at high magnetic fields

    SciTech Connect

    Wosnitza, J.; Wanka, S.; Hagel, J.; Qualls, J. S.; Brooks, J. S.; Balthes, E.; Schweitzer, D.; Schlueter, J. A.; Geiser, U.

    2000-04-04

    The authors report on Shubnikov-de Haas (SdH) and de Haas-van Alphen (dHvA) results for the highly two-dimensional (2D) organic superconductors {kappa}-(ET){sub 2}I{sub 3} ({Tc} = 3.5 K) and {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} ({Tc} = 4.4 K). The SdH oscillations of both materials show an apparent deviation from the well-understood 2D dHvA signal at low temperatures and high magnetic fields. For {kappa}-(ET){sub 2}I{sub 3}, the mechanism leading to this behavior still needs to be clarified. For {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3}, an anomalous steady background part of the magnetoresistance seems to account for the observed discrepancies.

  1. Fermiology of the organic superconductor {beta}''-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3}.

    SciTech Connect

    Wosnitza, J.

    1998-07-29

    We present a detailed Fermi-surface (FS) investigation of the quasi two-dimensional (2D) organic superconductor (T{sub c} {approx} 4.5 K) {beta}{double_prime}(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3}. In line with previous investigations, de Haas-van Alphen measurements in pulsed fields up to 60 T show a single oscillation frequency, F{sub 0} = 200 T, which corresponds to a FS size of about 5% of the first Brillouin zone. Angular dependent magnetoresistance oscillations (AMROs) are utilized for the exact determination of the in-plane FS, which is found to be a strongly elongated ellipsoid with an axes ratio of about 1:9. Transport measurements in static fields up to 33 T show an unusual temperature dependence of the Shubnikov-de Haas (SdH) signal, i.e., a decrease of the SdH amplitude with decreasing temperature.

  2. Electrical Transport Experiments at High Pressure

    SciTech Connect

    Weir, S

    2009-02-11

    High-pressure electrical measurements have a long history of use in the study of materials under ultra-high pressures. In recent years, electrical transport experiments have played a key role in the study of many interesting high pressure phenomena including pressure-induced superconductivity, insulator-to-metal transitions, and quantum critical behavior. High-pressure electrical transport experiments also play an important function in geophysics and the study of the Earth's interior. Besides electrical conductivity measurements, electrical transport experiments also encompass techniques for the study of the optoelectronic and thermoelectric properties of materials under high pressures. In addition, electrical transport techniques, i.e., the ability to extend electrically conductive wires from outside instrumentation into the high pressure sample chamber have been utilized to perform other types of experiments as well, such as high-pressure magnetic susceptibility and de Haas-van Alphen Fermi surface experiments. Finally, electrical transport techniques have also been utilized for delivering significant amounts of electrical power to high pressure samples, for the purpose of performing high-pressure and -temperature experiments. Thus, not only do high-pressure electrical transport experiments provide much interesting and valuable data on the physical properties of materials extreme compression, but the underlying high-pressure electrical transport techniques can be used in a number of ways to develop additional diagnostic techniques and to advance high pressure capabilities.

  3. Magnetic and Fermi Surface Properties of Ferromagnets EuPd2 and EuPt2

    NASA Astrophysics Data System (ADS)

    Nakamura, Ai; Akamine, Hiromu; Ashitomi, Yousuke; Honda, Fuminori; Aoki, Dai; Takeuchi, Tetsuya; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Tatetsu, Yasutomi; Maehira, Takahiro; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika

    2016-08-01

    We succeeded in growing single crystals of the ferromagnets EuPd2 and EuPt2 with the Laves-type cubic structure by the Bridgman method, namely, heating constituting materials in a Mo crucible up to a high temperature of about 1500 °C. The ferromagnetic properties of EuPd2 and EuPt2 with Curie temperatures of 74 and 100 K, respectively, were confirmed from the results of electrical resistivity, specific heat, and magnetization measurements. The ordered moment is 7 μB/Eu, revealing the Eu-divalent ferromagnetism. The present Eu-divalent electronic state is found to be robust against high pressures of up to 8 GPa and is not changed into the Eu-trivalent state. We also carried out de Haas-van Alphen (dHvA) experiments for EuPd2. The detected dHvA branches in EuPd2 are well explained by the relativistic linearized augmented plane wave (RLAPW) energy band calculations for SrPd2, revealing a closed hole Fermi surface and compensated four closed electron Fermi surfaces.

  4. Superconducting and Fermi Surface Properties of Single Crystal Zr2Co

    NASA Astrophysics Data System (ADS)

    Teruya, Atsushi; Kakihana, Masashi; Takeuchi, Tetsuya; Aoki, Dai; Honda, Fuminori; Nakamura, Ai; Haga, Yoshinori; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Harima, Hisatomo; Hedo, Masato; Nakama, Takao; Ōnuki, Yoshichika

    2016-03-01

    We succeeded in growing single crystals of a superconductor Zr2Co with the tetragonal structure by the Bridgman method and carried out electrical resistivity, magnetic susceptibility, magnetization, specific heat, and de Haas-van Alphen (dHvA) experiments. Superconductivity is a characteristic revealing that the electronic specific heat at 1.45 K in the form of Ce/T in the superconducting state increases not linearly but as a function of √{H} up to a magnetic field close to the upper critical field Hc2 = 11 kOe. The superconducting transition temperature Tsc is found to increase markedly with increasing pressure from Tsc = 5.2 K at ambient pressure to 9.5 K at 8 GPa. From the dHvA experiment, several kinds of dHvA branches are detected, which are well explained by the results of the energy band calculation. The main conduction electrons are Zr-4d and Co-3d electrons.

  5. Direct, experimental evidence of the Fermi surface in YBa sub 2 Cu sub 3 O sub 7-x

    SciTech Connect

    Haghighi, H.; Kaiser, J.H.; Rayner, S.L.; West, R.N. ); Liu, J.Z.; Shelton, R. ); Howell, R.H.; Sterne, P.A.; Solal, F.; Fluss, M.J. )

    1991-04-29

    We report new measurements of the electron-positron momentum spectra of YBa{sub 2}Cu{sub 3}O{sub 7-x} performed with ultra-high statistical precision. These data differ from previous results in two significant respects: They show the D{sub 2} symmetry appropriate for untwinned crystals and, more importantly, they show unmistakable, statistically significant, discontinuities that are evidence of a major Fermi surface section. These results provide a partial answer to a question of special significance to the study of high temperature superconductors i.e. the distribution of the electrons in the material, the electronic structure. Special consideration has been given both experimentally and theoretically to the existence and shape of a Fermi surface in the materials and to the superconducting gap. There are only three experimental techniques that can provide details of the electronic structure at useful resolutions. They are angular correlation of positron annihilation radiation, ACAR, angle resolved photo emission, PE, and de Haas van Alphen measurements. 11 refs., 4 figs.

  6. Heavy fermions, quantum criticality, and unconventional superconductivity in filled skutterudites and related materials

    SciTech Connect

    Andraka, Bohdan

    2015-05-14

    The main goal of this program was to explore the possibility of novel states and behaviors in Pr-based system exhibiting quantum critical behavior, PrOs₄Sb₁₂. Upon small changes of external parameter, such as magnetic field, physical properties of PrOs₄Sb₁₂ are drastically altered from those corresponding to a superconductor, to heavy fermion, to field-induced ordered phase with primary quadrupolar order parameter. All these states are highly unconventional and not understood in terms of current theories thus offer an opportunity to expand our knowledge and understanding of condensed matter. At the same time, these novel states and behaviors are subjects to intense international controversies. In particular, two superconducting phases with different transition temperatures were observed in some samples and not observed in others leading to speculations that sample defects might be partially responsible for these exotic behaviors. This work clearly established that crystal disorder is important consideration, but contrary to current consensus this disorder suppresses exotic behavior. Superconducting properties imply unconventional inhomogeneous state that emerges from unconventional homogeneous normal state. Comprehensive structural investigations demonstrated that upper superconducting transition is intrinsic, bulk, and unconventional. The high quality of in-house synthesized single crystals was indirectly confirmed by de Haas-van Alphen quantum oscillation measurements. These measurements, for the first time ever reported, spanned several different phases, offering unprecedented possibility of studying quantum oscillations across phase boundaries.

  7. The Magnetic Ordering of Heavy Rare Earth Metals

    NASA Astrophysics Data System (ADS)

    Nordström, Lars

    1998-03-01

    The electronic and magnetic structures of the rare earth metals with hcp structure (Gd--Tm) are calculated by a full-potential LAPW method, which allows for non-collinear magnetism within the local approximation to spin-density functional theory. The 4f electrons are taken as localized, but their spin moment constrained as to fulfil Russel-Saunders coupling, polarizes the itinerant valence electrons. It is found that there are two competing magnetic structures; the ferromagnetic state, which dominates for the left-most elements (Gd and Tb), and a planar helical wave, which is found to have lowest energy for the last elements Er and Tm. In Ho the competition between the two leads to a compromise --- a helical cone. This trend is in accordance with the experimental situation. The mechanism behind the stabilization of the helical wave is confirmed to be an opening of a partial gap at the so-called ``webbing'' of the Fermi surface. This feature is found to exhibit nesting, a fact which is known both from earlier non-spin-polarized calculations and de Haas-van Alphen measurements. In contrast to prevailing models and earlier more primitive calculations, this nesting is found to exist for all elements, i.e. even for gadolinium. Instead, the magnitude of the spin splitting of the valence electrons due to the magnetic 4f states, is found to be an important quantity which has been missed out in the standard models for the magnetic structure of the rare earths.

  8. Fermi Surface of Donor and Acceptor Graphite Intercalation Compounds.

    NASA Astrophysics Data System (ADS)

    Wang, Guonan

    The Fermi surfaces and the electronic properties of the donor-type stage-1 C_8K and stage-2 C_{24}K, as well as the acceptor-type stage-2 BiCl_3, stage-3 HgCl_2 and stage-3 SbF _5 graphite intercalation compounds were investigated by means of the de Haas-van Alphen effect. The dHvA spectra of the stage-1 C_8 K exhibit two dHvA frequencies, 3126 T and 4250 T. The corresponding effective masses were 0.86 m _0 and 0.92 m_0, respectively. The angular dependence of the dHvA frequencies for a direction within +/-18^circ of the c-axis showed that there are both three-dimensional and two dimensional parts of the Fermi surfaces in C _8K. The three-dimensional Fermi surface has a cross-sectional area corresponding to the dHvA frequency of 3126 T. The charge transfer per potassium atom measured from the dHvA effect is 0.97. This implies that the potassium is ionized completely. These dHvA experimental results support both the Tatar and Rabii model and the revised Ohno, Nakao and Kamimura model for C_8K. Two dominant dHvA frequencies were obtained in stage-2 C_{24}K. They are 286 T and 2570 T, respectively. The predictions of Blinowski's model are in agreement with the experimental data. The charge transfer per potassium is found to be 0.88. This suggests that the potassium s-band is above the Fermi level in C_{24}K. The dHvA measurements for the acceptor compounds show that the stage-2 BiCl_3 GIC had two dHvA frequencies, 327T and 1012T, and each stage -3 compound had three dominant frequencies. They are 121T, 523T and 664T for HgCl_2, and 172T, 656T and 852T for SbF_5. The cyclotron masses corresponding to the dHvA frequencies for these compounds were measured from the temperature dependence of the dHvA amplitudes. The theoretical predictions of the dHvA frequencies and the cyclotron masses from the Blinowski's band models for stage-2 and stage-3 compounds are in agreement with the experimental results. The angular dependence of the dHvA frequencies show that the Fermi

  9. Shell structure and classical orbits in mesoscopic systems

    NASA Astrophysics Data System (ADS)

    Tanaka, Kaori

    understanding of these phenomena, we apply a recently developed trace formula for broken symmetry to this system. The system of quantum dots is more interesting than metal clusters in that its size can be much larger and the effect of magnetic fields on the electronic shell structure is observable for readily available field strengths. We examine the magnetization and magnetic susceptibility of a circular quantum dot with the two limiting cases of mean-field potential for a small and large number of confined electrons. The shell structure rejected in these magnetic properties are compared in the two cases and are interpreted through short classical orbits. In particular, the Aharonov-Bohm oscillations that appear in the strong-field limit, superimposed on the de Haas-van Alphen oscillations in the magnetization, are explained in terms of the shortest orbits that go along the edge of the system.

  10. Skutterudites under pressure: An ab initio study

    SciTech Connect

    Ram, Swetarekha; Kanchana, V.; Valsakumar, M. C.

    2014-03-07

    Ab initio results on the band structure, density of states, and Fermi surface (FS) properties of LaRu{sub 4}X{sub 12} (X = P, As, Sb) are presented at ambient pressure as well as under compression. The analysis of density of states reveals the major contribution at the Fermi level to be mainly from the Ru-d and X-p states. We have a complicated Fermi surface with both electron and hole characters for all the three compounds which is derived mainly from the Ru-d and X-p states. There is also a simpler FS with hole character derived from the P-p{sub z} orbital for LaRu{sub 4}P{sub 12} and Ru-d{sub z{sup 2}} orbital in the case of As and Sb containing compounds. More interestingly, Fermi surface nesting feature is observed only in the case of the LaRu{sub 4}P{sub 12}. Under compression, we observe the topology of the complicated FS sheet of LaRu{sub 4}As{sub 12} to change around V/V{sub 0} = 0.85, leading to a behaviour similar to that of a multiband superconductor, and in addition, we have two more hole pockets centered around Γ at V/V{sub 0} = 0.8 for the same compound. Apart from this, we find the hole pocket to vanish at V/V{sub 0} = 0.8 in the case of LaRu{sub 4}Sb{sub 12} and the opening of the complicated FS sheet gets reduced. The de Haas van Alphen calculation shows the number of extremal orbits in the complicated sheet to change in As and Sb containing compounds under compression, where we also observe the FS topology to change.

  11. Fermi surface and magnetic structure of rare-earth-Ga3 compounds

    NASA Astrophysics Data System (ADS)

    Biasini, Maurizio; Kontrym-Sznajd, Grazyna; Ferro, Gianclaudio; Czopnik, Andrzej

    2002-03-01

    The measurement of the 2-dimensional angular correlation of the positron annihilation radiation (2D-ACAR), providing a 2D projection of the two-photon electron-positron momentum density, ρ(p), is a powerful tool to investigate the electronic structure of intermetallic compounds. Utilising tomographic reconstruction techniques (G Kontrym-Sznajd et al Mat. Scie. Forum 255-257) 754 (1997) and references therein., the experiment has the unique ability to sample the Brillouin Zone of truly 3-dimensional systems in a cartesian mesh, thus determining their Fermi surface (FS). Our studies have addressed the commensurate and incommensurate antiferromagnetic structures of TmGa3 and ErGa_3, respectively. For both compounds the FSs resulting from the 2D-ACAR experiments are in fair agreement with de Haas van Alphen measurements and with band structure calculations which constrain the 4f electrons to retain a local atomic character (M Biasini at al Phys. Rev. Lett 86), 4616, (2001).. Nevertheless, we discover different nesting features along the [110] directions which can account for the magnetic structures of the two compounds. Moreover, we propose methods to estimate the density of states at the Fermi energy (E_F) and the electronic contribution to the specific heat, γ. We obtain N(E_F)=17 states/ (Ryd cell), γ=2.8 (mJ/mole K^2) and N(E_F)=16 states/ (Ryd cell), γ=2.7 (mJ/mole K^2) for TmGa3 and ErGa_3, respectively.

  12. Heavy-Fermion Superconductivity in URANIUM-PLATINUM(3)

    NASA Astrophysics Data System (ADS)

    Putikka, William Oliver

    A phenomenological spin fluctuation model for superconductivity in the heavy-fermion metal UPt _3 is presented. The wavevector dependence of the interaction is assumed to be the same as the wavevector dependent magnetic susceptibility extracted from the neutron scattering experiments of Aeppli, et al. The other input for the calculation is the Fermi surface of UPt _3. Single particle band calculations done for UPt_3 give a Fermi surface which is very anisotropic. Despite the presence of strong correlations in UPt_3 the Fermi surface derived from band calculations is confirmed by the de Haas-van Alphen measurements of Taillefer, et al. However, the calculated band masses are smaller than the observed masses by a factor of 20. UPt_3 can thus be described at low temperatures in its normal state as a Fermi liquid, with very massive quasiparticles. The model considered here for the superconducting state is the pairing of the heavy quasiparticles by means of the spin fluctuation mediated interaction. A phase diagram is derived in terms of two dimensionless parameters giving the relative strength of the local repulsive part of the interaction and the in plane ferromagnetic interaction compared to the nearest neighbor antiferromagnetic interaction. s -, p- and d-wave phases are possible. The symmetry of the gap function favored by this model is the E_ {1g} representation of D_ {rm 6h}. To determine the symmetry of the gap function for this two dimensional representation the fourth order terms in the Ginzburg-Landau free energy are considered. The resulting gap function has a line of nodes in the basal plane and point nodes along the c -axis. A qualitative comparison of calculated properties for UPt_3 with this d-wave gap function to measured properties is given. Emphasis is on the observed power law temperature dependences for many low temperature properties and the difficulties in identifying the nodal structure due to impurity scattering. A discussion of the limitations

  13. Photoemission studies of classic and novel thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Greanya, Viktoria Augusta

    Thermoelectric materials have been studied vigorously since the 1950s. Recent advances in materials synthesis and theory have rejuvinated the field in the last decade. The thermoelectric properties of materials are related to their electronic structure. In addition, many of these materials behave quasi-low-dimensionally, making them ideal candidates for study using angle resolved and angle integrated photoelectron spectroscopy (ARPES and AIPES). We report the first detailed study of the valence band electronic structure of Bi2Te3, Bi2Se3 and CsBi 4Te6 using ARPES and AIPES. Experimental results are compared with local density approximation (LDA) band structure calculations and (when available) with de Haas-van Alphen and Shubnikov-de Haas experiments. Bi2Te3 is currently the best room temperature thermoelectric material known. Dispersions of the valence bands were determined using ARPES. A six-fold k-space degeneracy in the valence band maximum is found. The quasi-two-dimensional nature of the electronic structure was demonstrated by the weakly dispersive bands along the Gamma-Z direction. The density of states (DOS) for this material was also studied using AIPES. Spectra were taken at multiple photon energies. Six valence band peaks were found. Good correspondence with the calculated DOS was found. Bi2Se3 is isostructural to Bi2Te 3 but its thermoelectric performance is significantly worse. The valence band dispersions for this material have been determined, as well as the DOS. We find the valence band maximum to be located at Gamma. Ten easily identifiable bands are seen within 4 eV of the Fermi level. The energy bands in the Gamma-Z direction are found to be flatter than those predicted by theory. The APES measurements revealed a total of nine bands, which correspond well to the calculated DOS. CsBi4Te6 is a novel thermoelectric material, recently discovered in the chemistry department of Michigan State University. This material exhibits quasi

  14. Competing order, Fermi surface reconstruction, and quantum oscillations in underdoped high-temperature superconductors

    NASA Astrophysics Data System (ADS)

    Dimov, Ivailo; Goswami, Pallab; Jia, Xun; Chakravarty, Sudip

    2008-10-01

    We consider incommensurate order parameters for electrons on a square lattice which reduce to d -density wave order when the ordering wave vector Q is close to Q0=(π/a,π/a) , a being the lattice spacing and describe the associated charge and current distributions within a single-harmonic approximation that conserves current to lowest order. Such incommensurate orders can arise at the mean-field level in extended Hubbard models, but the main goal here is to explore thoroughly the consequences within a Hartree-Fock approximation. We find that Fermi surface reconstruction in the underdoped regime can correctly capture the phenomenology of the recent quantum oscillation experiments that suggest incommensurate order, in particular the de Haas-van Alphen oscillations of the magnetization in high fields and very low temperatures in presumably the mixed state of these superconductors. For 10% hole doping in YBa2Cu3O6+δ , we find in addition to the main frequency around 530 T arising from the electron pocket and a hole frequency at around 1650 T, a new low frequency from a smaller hole pocket at 250 T for which there are some indications that require further investigations. The oscillation corresponding to the electron pocket will be further split due to bilayer coupling, but the splitting is sufficiently small to require more refined measurements. The truly incommensurate d -density wave breaks both time reversal and inversion, but the product of these two symmetry operations is preserved. The resulting Fermi surface splits into spin-up and spin-down sectors that are inversion conjugates. Each of the spin sectors results in a band structure that violates reflection symmetry, which can be determined in spin and angle-resolved photoemission spectroscopies. For those experiments such as the current photoemission experiments or the quantum oscillation measurements that cannot resolve the spin components, the bands will appear to be symmetric because of the equal mixture of

  15. Are Effective Properties Effective?

    SciTech Connect

    Han, Ru; Ingber, Marc S.; Hsiao, S.-C.

    2008-02-15

    The effective moduli (effective Young's modulus, effective Poisson's ratio, effective shear modulus, and effective bulk modulus) of dispersed-phase-reinforced composite materials are determined at the mesoscopic level using three-dimensional parallel boundary element simulations. By comparing the mesoscopic BEM results and the macroscopic results based on effective properties, limitations in the effective property approach have been examined.

  16. Side Effects

    MedlinePlus

    ... 2014 Select a Language: Fact Sheet 550 Side Effects WHAT ARE SIDE EFFECTS? WHO GETS SIDE EFFECTS? ... t assume that you will get every side effect that’s listed! Most people have few or only ...

  17. A Poetic Journey: The Transfer and Transformation of German Strategies for Moral Education in Late Eighteenth-Century Dutch Poetry for Children

    ERIC Educational Resources Information Center

    Parlevliet, Sanne; Dekker, Jeroen J. H.

    2013-01-01

    One of the most popular Dutch educational enlightenment authors was Hieronymus van Alphen. His three volumes of "Little Poems for Children" published in 1778 and 1782 were extremely successful, both in the Netherlands and abroad. Inspired by the German poets Christian Felix Weisse and Gottlob Wilhelm Burmann, Van Alphen brought about an…

  18. Thermal Effects.

    ERIC Educational Resources Information Center

    Talmage, Sylvia S.; Coutant, Charles C.

    1978-01-01

    Presents a literature review of the effect of temperature on the biosphere water, covering publications of 1976-77. This review includes the effects of temperature on growth, production, and embryonic and larval development. A list of 401 references is also presented. (HM)

  19. "Further Effects"

    NASA Astrophysics Data System (ADS)

    Kinigstein, Steven Michael

    In writing Further Effects, I intended to illustrate the benefits that are to be had from the use of effects - processing, when applied at the compositional level, rather than as a post-compositional afterthought. When effects are used creatively in the compositional stage, they will influence the very nature of a piece. They are capable of expressing rhythmic and metric ideas. They can alter the natural timbre of an instrument. This can be done on levels of abstraction ranging from discreet subtlety to disguise beyond recognition. There is one effect (known as "pitch shift.") that allows an instrument to play pitches that are well outside of its range. In Further Effects, I direct the performers to use a volume pedal (which I view as a tool, rather than an effect) for the broadened creative use of dynamics that it so efficiently grants. The use of an effects processor and volume pedal creates a need for ancillary equipment. An amplifier, cables, and an electric hook-up (a microphone or a pickup) will be required for each instrument. While an amplifier serves to project the processed sound, there must also be a device or method to suppress unprocessed sound. A great deal of thought and work goes into the use of effects; yet I feel it is wasteful to use this musical resource merely as post-compositional decoration.

  20. Thermal effects

    SciTech Connect

    Harrelson, M.E.; Talmadge, S.S.; Cravens, J.B.

    1984-06-01

    A literature review is presented of recent studies on the role of temperature effects and change in temperature caused by thermal power plants on aquatic life. Several of these studies involve the use of models that allow testing of hypotheses concerning the effects of temperature on fish and insects. 91 references.

  1. Gauging Effectiveness

    ERIC Educational Resources Information Center

    Foord, Kathleen A.; Haar, Jean M.

    2012-01-01

    Books by education experts and speakers at national professional conferences have inspired many school leaders to initiate professional learning communities (PLCs). Sustaining them effectively to raise student achievement is another matter. How can one know whether a PLC is moving toward a desired outcome? Measuring effectiveness requires an…

  2. Effective Schools Require Effective Principals

    ERIC Educational Resources Information Center

    LaPointe, Michelle; Davis, Stephen H.

    2006-01-01

    At long last, scholars and policy makers have come to realize what most school administrators have known for years--that effective schools require both outstanding teachers and strong leaders. Although there is considerable research about the characteristics of effective school leaders and the strategies principals can use to help manage…

  3. Physical properties of single crystalline BaSn{sub 5}

    SciTech Connect

    Lin, Xiao; Budko, Sergey; Canfield, Paul

    2012-01-30

    We present a comprehensive study of the binary intermetallic superconductor, BaSn{sub 5}. High-quality single crystalline BaSn{sub 5} was grown out of a Sn flux. Detailed thermodynamic and transport measurements were performed to study BaSn{sub 5}'s normal and superconducting state properties. This material appears to be a strongly coupled, multiband superconductor. H{sub c2}(T) is almost isotropic. De Haas–van Alphen oscillations were observed and two effective masses were estimated from the FFT spectra. Hydrostatic pressure causes a decrease in the superconducting transition temperature at the rate of ≈−0.053 ± 0.001 K/kbar.

  4. Health Effects

    MedlinePlus

    ... Chapter . Additional information regarding the health effects of climate change and references to supporting literature can be found ... globalchange.gov/engage/activities-products/NCA3/technical-inputs . Climate change, together with other natural and human-made health ...

  5. Plasma Effects

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.

    1983-01-01

    Radio communication with space probes requires sending signals through the Earth's ionosphere and usually the solar wind. During planetary flybys, the signal may also pass through the ionosphere of another planet. These ionized media can perturb the radio signal in a variety of ways. Examples of these perturbations are variations in the electrical length between the spacecraft and the ground station, Faraday rotation of linearly polarized signals, amplitude and phase scintillations, and spectral and angular broadening. These plasma effects can have undesirable influences on telemetry performance and thus need to be understood from a communications engineering viewpoint. The plasma effects are, however, useful from a scientific viewpoint, since the effects on the communications link can often be inverted to estimate the physical conditions in the plasma.

  6. Thermal Effects.

    PubMed

    Zhang, Panyue; Ye, Jie; Zeng, Guangming

    2015-10-01

    This review focuses on the research literatures published in 2014 relating to topics of thermal effects in water pollution control. This review is divided into the following sections: anaerobic wastewater and sludge treatment, biological nitrogen and phosphorus removal, membrane biological treatment, sewage sludge pyrolysis, natural treatment, resource recovery, electrolysis, oxidation and adsorption treatment. PMID:26420108

  7. Communicating Effectively

    Cancer.gov

    The seventh module of the EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study: Cultural Considerations When Caring for African Americans explores communication issues pertinent to African Americans with cancer and their health care providers, discusses strategies for culturally sensitive communication, and presents the SPIKES protocol, a practical framework for effective communication.

  8. Sleeper Effects

    ERIC Educational Resources Information Center

    Maurer, Daphne; Mondloch, Catherine J.; Lewis, Terri L.

    2007-01-01

    Early experience preserves and refines many capabilities that emerge prenatally. Here we describe another role that it plays--establishing the neural substrate for capabilities that emerge at a much later point in development. The evidence comes from sleeper effects: permanent deficits when early experience was absent in capabilities that normally…

  9. System Effectiveness

    SciTech Connect

    Powell, Danny H; Elwood Jr, Robert H

    2011-01-01

    An effective risk assessment system is needed to address the threat posed by an active or passive insider who, acting alone or in collusion, could attempt diversion or theft of nuclear material. It is critical that a nuclear facility conduct a thorough self-assessment of the material protection, control, and accountability (MPC&A) system to evaluate system effectiveness. Self-assessment involves vulnerability analysis and performance testing of the MPC&A system. The process should lead to confirmation that mitigating features of the system effectively minimize the threat, or it could lead to the conclusion that system improvements or upgrades are necessary to achieve acceptable protection against the threat. Analysis of the MPC&A system is necessary to understand the limits and vulnerabilities of the system to internal threats. Self-assessment helps the facility be prepared to respond to internal threats and reduce the risk of theft or diversion of nuclear material. MSET is a self-assessment or inspection tool utilizing probabilistic risk assessment (PRA) methodology to calculate the system effectiveness of a nuclear facility's MPC&A system. MSET analyzes the effectiveness of an MPC&A system based on defined performance metrics for MPC&A functions based on U.S. and international best practices and regulations. A facility's MC&A system can be evaluated at a point in time and reevaluated after upgrades are implemented or after other system changes occur. The total system or specific subareas within the system can be evaluated. Areas of potential performance improvement or system upgrade can be assessed to determine where the most beneficial and cost-effective improvements should be made. Analyses of risk importance factors show that sustainability is essential for optimal performance. The analyses reveal where performance degradation has the greatest detrimental impact on total system risk and where performance improvements have the greatest reduction in system risk

  10. Blazhko Effect

    NASA Technical Reports Server (NTRS)

    Teays, Terry

    1996-01-01

    The cause of the Blazhko effect, the long-term modulation of the light and radial velocity curves of some RR Lyr stars, is still not understood. The observational characteristics of the Blazhko effect are discussed. Some preliminary results are presented from two recent campaigns to observe RR Lyr, using the International Ultraviolet Explorer along with ground-based spectroscopy and photometry, throughout a pulsation cycle, at a variety of Blazhko phases. A set of ultraviolet light curves have been generated from low dispersion IUE spectra. In addition, the (visual) light curves from IUE's Fine Error Sensor are analyzed using the Fourier decomposition technique. The values of the parameters Psi(sub 21) and R(sub 21) at different Blazhko phases of RR Lyr span the range of values found for non-Blazhko variables of similar period.

  11. Zeeman Effect

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The splitting of a spectral line into two, three or more components, that occurs when the source of that line lies within a magnetic field. This phenomenon is named after the Dutch physicist, Pieter Zeeman (1865-1943), who discovered the effect in the laboratory, in 1896. The separation of the components of a line is proportional to the strength of the magnetic field and the number of components,...

  12. Thermal Effects.

    PubMed

    Yan, Ming; Zhang, Panyue; Zeng, Guangming

    2016-10-01

    This review focuses on the research literatures published in 2015 relating to topics of thermal effects in water pollution control. This review is divided into the following sections: biological nitrogen and phosphorus removal, wastewater treatment for organic conversion, industrial wastewater treatment, anaerobic digestion of sewage sludge and solid waste, sludge biochar preparation and application, pyrolysis of sewage sludge, reduction heavy metal in sewage sludge and soil, and other issues of wastewater and sludge treatment. PMID:27620109

  13. Erosion Effects

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The impact crater in this THEMIS image is a model illustration to the effects of erosion on Mars. The degraded crater rim and several landslides observed in crater walls is evidence to the mass wasting of materials. Layering in crater walls also suggests the presence of materials that erode at varying rates.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 31.6, Longitude 44.3 East (315.7 West). 19 meter/pixel resolution.

  14. Effective committees.

    PubMed

    Collins, Jannette

    2012-03-01

    A committee is a group of people officially delegated to perform a function, such as investigating, considering, reporting, or acting on a matter. Some committees function like task forces and work on specific, time-limited projects. When the work is finished, the committees are no longer needed. These committees are called ad hoc committees. Other committees are standing committees. They are created by the standing orders, rules, by-laws, or regulations of an organization and exist and function indefinitely (eg, finance, membership, education, nomination). Both types of committees can form subcommittees if the workloads are heavy or complex in nature. Committees can be among the most important working forces of an organization. They serve as work units of the organization, taking work and breaking it into meaningful and manageable chunks. They efficiently carry out the work of the organization. Committee work should be a rewarding experience for both the members and the organization. Committees represent, involve, and serve members, as well as provide an important training ground for future leaders of an organization. New or inexperienced members can gain valuable insight into an organization and develop confidence by serving on committees. There are several key elements of effective committees, including (1) a clear, written purpose; (2) an effective committee chair; (3) thoughtfully appointed members; and (4) well-run meetings. PMID:22386164

  15. Microbial effects

    SciTech Connect

    Lamborg, M.R.; Hardy, R.W.F.; Paul, E.A.

    1983-01-01

    The postulated doubling of atmospheric CO/sub 2/ is not likely to have direct effect on soil microbial activity because during the growing season, the concentration of CO/sub 2/ in the soil atmosphere is already ten to fifty times higher than existing atmospheric CO/sub 2/. Based on all available experimental information, it is estimated that a doubling of atmospheric CO/sub 2/ will cause an increase in primary productivity of 10 to 40% depending on locale. The increase in biomass will, in turn, produce a limitation of available soil nutrients, especially nitrogen and phosphorus. Increased organic carbon together with nitrogen and/or phosphorus limitation will result in a preferential increase in nitrogen fixation and mycorrhizal activities as the expedient means for supplying required nutrients to sustain the predicted increase in primary productivity. Therefore, increased emphasis should be placed on fundamental research related to soil microbiology with special reference to nitrogen-fixing, nitrifying and denitrifying bacteria, and to the mycorrhizal fungi. 111 references, 2 figures.

  16. Effective Teaching/Effective Urban Teaching

    ERIC Educational Resources Information Center

    Watson, Dyan; Charner-Laird, Megin; Kirkpatrick, Cheryl L.; Szczesiul, Stacy Agee; Gordon, Pamela J.

    2006-01-01

    This article considers the ways in which 17 novice teachers define and describe effective urban teaching and the stark contrasts that these teachers draw between effective urban teaching and effective teaching. The authors find that descriptions of students played a considerable role when participants made distinctions between effective teaching…

  17. Social Context Effects on School Effects.

    ERIC Educational Resources Information Center

    Hallinger, Philip; Murphy, Joseph

    In this two-part paper, an attempt is made to examine the relationship between social contexts and effective schools and specifically to contribute to the development of a conceptual model for understanding how social contexts influence the operation of effective schools and student learning. In the first part, school effects research is drawn…

  18. On Effect Size

    ERIC Educational Resources Information Center

    Kelley, Ken; Preacher, Kristopher J.

    2012-01-01

    The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension,…

  19. Improving School Effectiveness.

    ERIC Educational Resources Information Center

    MacBeath, John, Ed.; Mortimore, Peter, Ed.

    School effectiveness is an issue that has preoccupied researchers and policymakers for 3 decades. To study how ineffective schools become effective and what constitutes an effective school, the Improving School Effectiveness Project was carried out in Scotland from 1995 to 1997. This project forms the basis of discussion in this book, which has 11…

  20. On effect size.

    PubMed

    Kelley, Ken; Preacher, Kristopher J

    2012-06-01

    The call for researchers to report and interpret effect sizes and their corresponding confidence intervals has never been stronger. However, there is confusion in the literature on the definition of effect size, and consequently the term is used inconsistently. We propose a definition for effect size, discuss 3 facets of effect size (dimension, measure/index, and value), outline 10 corollaries that follow from our definition, and review ideal qualities of effect sizes. Our definition of effect size is general and subsumes many existing definitions of effect size. We define effect size as a quantitative reflection of the magnitude of some phenomenon that is used for the purpose of addressing a question of interest. Our definition of effect size is purposely more inclusive than the way many have defined and conceptualized effect size, and it is unique with regard to linking effect size to a question of interest. Additionally, we review some important developments in the effect size literature and discuss the importance of accompanying an effect size with an interval estimate that acknowledges the uncertainty with which the population value of the effect size has been estimated. We hope that this article will facilitate discussion and improve the practice of reporting and interpreting effect sizes. PMID:22545595

  1. Regulation with placebo effects.

    PubMed

    Malani, Anup

    2008-12-01

    A growing scientific literature supports the existence of placebo effects from a wide range of health interventions and for a range of medical conditions. This Article reviews this literature, examines the implications for law and policy, and suggests future areas for research on placebo effects. In particular, it makes the case for altering the drug approval process to account for, if not credit, placebo effects. It recommends that evidence of placebo effects be permitted as a defense in cases alleging violations of informed consent or false advertising. Finally, it finds that tort law already has doctrines such as joint and several liability to account for placebo effects. Future research on placebo effects should focus on whether awareness of placebo effects can disable these effects and whether subjects can control their own placebo effects. PMID:19353835

  2. [Placebo and placebo effect].

    PubMed

    Aulas, J-J

    2005-11-01

    The word placebo appeared for the first time in an English medical dictionary in 1785. In French, it appeared much latter in 1958. This word defines an experimental tool used for rigourous evaluation of a specific effect of pharmacological treatment and the non specific effect of any therapy. The placebo effect is the strictly psychological or psychophysiological effect of a placebo. The two principal components of placebo effect as a pain killer, which has been extensively studied in this field, are positive expectancies of both the patient and the physician. Although the mechanisms of action of placebo effect are not well understood, results of several recent works are particularly interesting. PMID:16292233

  3. Stormwater BMP Effectiveness Toolkit

    EPA Science Inventory

    US EPA has identified the effectiveness of Stormwater Best Management Practices (BMPs) as a priority research need. Effective protection of biotic integrity requires that processes maintaining the diversity of physical habitats be protected. Methods are needed to evaluate the e...

  4. Memory effects in turbulence

    NASA Technical Reports Server (NTRS)

    Hinze, J. O.

    1979-01-01

    Experimental investigations of the wake flow of a hemisphere and cylinder show that such memory effects can be substantial and have a significant influence on momentum transport. Memory effects are described in terms of suitable memory functions.

  5. Side Effects (Management)

    MedlinePlus

    ... Cancer is Treated Side Effects Dating, Sex, and Reproduction Advanced Cancer For Children For Teens For Young ... Cancer is Treated Side Effects Dating, Sex, and Reproduction Advanced Cancer For Children For Teens For Young ...

  6. Effective College Teaching.

    ERIC Educational Resources Information Center

    Caraway, James E.

    1978-01-01

    The author discusses other writings on effective college teaching and then presents his list of necessary characteristics for the effective teacher, stressing the interpersonal dimension of the teaching-learning situation. (MF)

  7. The Hydrophobic Effect.

    ERIC Educational Resources Information Center

    Huque, Entazul M.

    1989-01-01

    Discusses the physical basis and current understanding of hydrophobic effects. The thermodynamic background of the effects, hydrophobic hydration, and hydrophobic interactions are described. Four existing controversies are outlined. (YP)

  8. Emotional Side Effects

    MedlinePlus

    ... window. My Saved Articles » My ACS » Emotional Side Effects In this section you can learn more about ... Finding and Paying for Treatment Treatments and Side Effects Survivorship: During and After Treatment Children and Cancer ...

  9. Hormonal effects in newborns

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/001911.htm Hormonal effects in newborns To use the sharing features on this page, please enable JavaScript. Hormonal effects in newborns occur because in the womb babies ...

  10. Effects of Nuclear Weapons.

    ERIC Educational Resources Information Center

    Sartori, Leo

    1983-01-01

    Fundamental principles governing nuclear explosions and their effects are discussed, including three components of a nuclear explosion (thermal radiation, shock wave, nuclear radiation). Describes how effects of these components depend on the weapon's yield, its height of burst, and distance of detonation point. Includes effects of three…

  11. Andexanet: Effectively Reversing Anticoagulation.

    PubMed

    Lippi, Giuseppe; Sanchis-Gomar, Fabian; Favaloro, Emmanuel J

    2016-06-01

    Despite direct oral anticoagulants becoming a mainstay of anticoagulant therapy, the effective, timely, and safe reversal of their anticoagulant effect remains challenging. Emerging evidence attests that andexanet, a recombinant and inactive variant of native factor X (FXa), competitively inhibits and counteracts the anticoagulant effect of many inhibitors of native activated FXa. PMID:27048885

  12. Effects of spatial resolution

    NASA Technical Reports Server (NTRS)

    Abrams, M.

    1982-01-01

    Studies of the effects of spatial resolution on extraction of geologic information are woefully lacking but spatial resolution effects can be examined as they influence two general categories: detection of spatial features per se; and the effects of IFOV on the definition of spectral signatures and on general mapping abilities.

  13. Effective Schools Research.

    ERIC Educational Resources Information Center

    Levine, Daniel U.; Lezotte, Lawrence W.

    Research studies that have focused on identifying the characteristics or correlates of elementary and secondary schools that are unusually effective are reviewed, concentrating on the "effective schools" movement. Research on effective schools supports the conclusion that they rank high on certain characteristics frequently referred to as…

  14. Effective Teachers of Literacy.

    ERIC Educational Resources Information Center

    Medwell, Jane; Wray, David; Poulson, Louise; Fox, Richard

    A study was commissioned to help the Teacher Training Agency and teachers in England to understand more clearly how effective teachers help children to become literate. Research aims were to: identify the key factors of what effective teachers know, understand, and do that enables them to put effective literacy teaching into practice; identify the…

  15. Characteristics of Effective Organizations.

    ERIC Educational Resources Information Center

    Whetten, David A.; Cameron, Kim S.

    THe confusing and often contradictory literature on organizational effectiveness is reviewed briefly, followed by a discussion of the leading models of effectiveness, their relative applicability to colleges and universities, questions for guiding the design of a specific study of organizational effectiveness, and guidelines for effective…

  16. Special Effects Activity Guide.

    ERIC Educational Resources Information Center

    Boxer, Jennifer; Valenta, Carol

    This guide accompanies "Special Effects," a 40-minute IMAX film and "Special Effects II", a multimedia, interactive traveling exhibit designed by the California Museum of Science and Industry. The exhibit focuses on the underlying scientific and technical processes of special effects from the earliest motion picture to state-of-the-art digital…

  17. Quasi-two-dimensional spin-split Fermi-liquid behavior of {kappa}-(BEDT-TTF){sub 2}I{sub 3} in strong magnetic fields

    SciTech Connect

    Harrison, N.; Mielke, C.H.; Rickel, D.G.; Wosnitza, J.; Qualls, J.S.; Brooks, J.S.; Balthes, E.; Schweitzer, D.; Heinen, I.; Strunz, W.

    1998-10-01

    Measurements of both the magnetization and magnetotransport of {kappa}-(BEDT-TTF){sub 2}I{sub 3} (BEDT-TTF is bisethylenedithio-tetrathiafulvalene) in magnetic fields extending to 60 T at 0.4 K and 20 T at 35 mK are reported. Strong eddy currents observed in the magnetization are found to exhibit critical currentlike behavior. This might be connected with the breakdown of the quantum Hall effect, as proposed previously for {alpha}-phase salts. The strong two dimensionality leads to an apparent fall of the effective mass together with an overall suppression of the amplitude of the magnetic quantum oscillations at high magnetic fields or very low temperatures. These effects are more pronounced for the Shubnikov{endash}de Haas (SdH) effect but clearly visible also for the de Haas{endash}van Alphen (dHvA) oscillations. The apparent fall of the effective mass and the deviations of the dHvA signal from the behavior predicted by the standard Lifshitz-Kosevich theory can quantitatively be explained by the influence of chemical-potential oscillations on the wave form in a two-dimensional, spin-split Fermi liquid. The much stronger deviations from the conventional behavior in the transport data hint to an additional mechanism unique to the SdH effect. thinsp {copyright} {ital 1998} {ital The American Physical Society}

  18. The butterfly effect of the "butterfly effect".

    PubMed

    Dooley, Kevin J

    2009-07-01

    The "Butterfly Effect" metaphor states with variance that the flap of a butterfly's wings in Brazil can cause a tornado in Texas. This metaphor has become part of the common vernacular of Western culture. In this paper I discuss the origins of the metaphor, examine its current usage within popular culture, and present an argument as to why it is popular. I propose that the metaphor is a type of semantic attractor, a narrative device with invariant meaning but audience-specific contextualization. Finally I address whether the Butterfly Effect metaphor is a good example of itself. PMID:19527619

  19. Side Effects of Hormone Therapy

    MedlinePlus

    ... Men Living with Prostate Cancer Side Effects of Hormone Therapy Side Effects Urinary Dysfunction Bowel Dysfunction Erectile Dysfunction Loss of Fertility Side Effects of Hormone Therapy Side Effects of Chemotherapy Side Effects: When ...

  20. Running effective meetings, running effective groups.

    PubMed

    Ogborn, S E

    1994-12-01

    Meetings are effective if they meet the objectives of each person involved in the least amount of time possible. Different strategies are needed for different types of meetings. Different leadership styles are necessary depending on the members' personality preferences and the stages of the group's development. Good leaders know how to adapt to these preferences and stages. PMID:10139146

  1. Effect identification in comparative effectiveness research.

    PubMed

    Oakes, J Michael

    2013-01-01

    The widespread adoption of electronic medical records means there are now vast data resources available for comparative effectiveness research (CER). In concert with conventional randomized controlled trials, CER holds great promise for advancing our understanding of how different therapeutic treatments yield different health outcomes in different settings and with different populations. But in a research culture fixated on estimating correlations and p-values, the threat of misinterpretation of results and improper CER inferences is troubling. Accordingly, this paper aims to shore up the inferential foundations of CER by introducing the fundamentals of effect identification, which is the process of identifying or teasing out empirically defensible causal effects from competing explanations. Three primary requirements of effect identification-positivity, exchangeability, and consistency- are explained and simple exampled are given. The take home message is that so-called big data from medical records may not yield better or more useful results. Advances will come only when the right question is addressed with the appropriate data and methods. PMID:25848556

  2. Enhanced magnetocaloric effect material

    DOEpatents

    Lewis, Laura J. H.

    2006-07-18

    A magnetocaloric effect heterostructure having a core layer of a magnetostructural material with a giant magnetocaloric effect having a magnetic transition temperature equal to or greater than 150 K, and a constricting material layer coated on at least one surface of the magnetocaloric material core layer. The constricting material layer may enhance the magnetocaloric effect by restriction of volume changes of the core layer during application of a magnetic field to the heterostructure. A magnetocaloric effect heterostructure powder comprising a plurality of core particles of a magnetostructural material with a giant magnetocaloric effect having a magnetic transition temperature equal to or greater than 150 K, wherein each of the core particles is encapsulated within a coating of a constricting material is also disclosed. A method for enhancing the magnetocaloric effect within a giant magnetocaloric material including the step of coating a surface of the magnetocaloric material with a constricting material is disclosed.

  3. Dynamic ground effects

    NASA Technical Reports Server (NTRS)

    Paulson, John W., Jr.; Kemmerly, Guy T.; Gilbert, William P.

    1990-01-01

    A research program is underway at the NASA Langley Research Center to study the effect of rate of descent on ground effects. A series of powered models were tested in the Vortex Research Facility under conditions with rate of descent and in the 14 x 22 Foot Subsonic Tunnel under identical conditions but without rate of descent. These results indicate that the rate of descent can have a significant impact on ground effects particularly if vectored or reversed thrust is used.

  4. Atomic lighthouse effect.

    PubMed

    Máximo, C E; Kaiser, R; Courteille, Ph W; Bachelard, R

    2014-11-01

    We investigate the deflection of light by a cold atomic cloud when the light-matter interaction is locally tuned via the Zeeman effect using magnetic field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease in magnetic field efficiency. PMID:25401364

  5. Atomic lighthouse effect

    NASA Astrophysics Data System (ADS)

    Máximo, C. E.; Kaiser, R.; Courteille, Ph. W.; Bachelard, R.

    2014-11-01

    We investigate the deflection of light by a cold atomic cloud when the light-matter interaction is locally tuned via the Zeeman effect using magnetic field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease of the magnetic field efficiency.

  6. Volcano-electromagnetic effects

    USGS Publications Warehouse

    Johnston, Malcolm J. S.

    2007-01-01

    Volcano-electromagnetic effects—electromagnetic (EM) signals generated by volcanic activity—derive from a variety of physical processes. These include piezomagnetic effects, electrokinetic effects, fluid vaporization, thermal demagnetization/remagnetization, resistivity changes, thermochemical effects, magnetohydrodynamic effects, and blast-excited traveling ionospheric disturbances (TIDs). Identification of different physical processes and their interdependence is often possible with multiparameter monitoring, now common on volcanoes, since many of these processes occur with different timescales and some are simultaneously identified in other geophysical data (deformation, seismic, gas, ionospheric disturbances, etc.). EM monitoring plays an important part in understanding these processes.

  7. Cardiac effects of vasopressin.

    PubMed

    Pelletier, Jean-Sébastien; Dicken, Bryan; Bigam, David; Cheung, Po-Yin

    2014-07-01

    Vasopressin is an essential hormone involved in the maintenance of cardiovascular homeostasis. It has been in use therapeutically for many decades, with an emphasis on its vasoconstrictive and antidiuretic properties. However, this hormone has a ubiquitous influence and has specific effects on the heart. Although difficult to separate from its powerful vascular effects in the clinical setting, a better understanding of vasopressin's direct cardiac effects could lead to its more effective clinical use for a variety of shock states by maximizing its therapeutic benefit. The cardiac-specific effects of vasopressin are complex and require further elucidation. Complicating our understanding include the various receptors and secondary messengers involved in vasopressin's effects, which may lead to various results based on differing doses and varying environmental conditions. Thus, there have been contradictory reports on vasopressin's action on the coronary vasculature and on its effect on inotropy. However, beneficial results have been found and warrant further study to expand the potential therapeutic role of vasopressin. This review outlines the effect of vasopressin on the coronary vasculature, cardiac contractility, and on hypertrophy and cardioprotection. These cardiac-specific effects of vasopressin represent an interesting area for further study for potentially important therapeutic benefits. PMID:24621650

  8. Volcanic effects on climate

    NASA Technical Reports Server (NTRS)

    Robock, Alan

    1991-01-01

    Volcanic eruptions which inject large amounts of sulfur-rich gas into the stratosphere produce dust veils which last years and cool the earth's surface. At the same time, these dust veils absorb enough solar radiation to warm the stratosphere. Since these temperature changes at the earth's surface and in the stratosphere are both in the opposite direction of hypothesized effects from greenhouse gases, they act to delay and mask the detection of greenhouse effects on the climate system. Tantalizing recent research results have suggested regional effects of volcanic eruptions, including effects on El Nino/Southern Oscillation (ENSO). In addition, a large portion of the global climate change of the past 100 years may be due to the effects of volcanoes, but a definite answer is not yet clear. While effects of several years were demonstrated with both data studies and numerical models, long-term effects, while found in climate model calculations, await confirmation with more realistic models. Extremely large explosive prehistoric eruptions may have produced severe weather and climate effects, sometimes called a 'volcanic winter'. Complete understanding of the above effects of volcanoes is hampered by inadequacies of data sets on volcanic dust veils and on climate change. Space observations can play an increasingly important role in an observing program in the future. The effects of volcanoes are not adequately separated from ENSO events, and climate modeling of the effects of volcanoes is in its infancy. Specific suggestions are made for future work to improve the knowledge of this important component of the climate system.

  9. Interdependence and Group Effectiveness.

    ERIC Educational Resources Information Center

    Wageman, Ruth

    1995-01-01

    Investigated the differential effects of task design and reward system design on group functioning in a large U.S. corporation; the effectiveness of "hybrid" groups (having tasks and rewards with both individual and group elements); and how individuals' autonomy preferences moderate their responses to interdependence. Groups performed best when…

  10. Effective rigidity of membranes

    NASA Astrophysics Data System (ADS)

    Peliti, L.

    1986-12-01

    The role of thermal fluctuations of shape (undulations) in reducing the effective rigidity of membranes is reviewed. The consequences of this effect on vesicle size distribution and on the structure of microemulsions, as well as on other physical phenomena, are sketched.

  11. Defining Effective Teaching

    ERIC Educational Resources Information Center

    Layne, L.

    2012-01-01

    The author looks at the meaning of specific terminology commonly used in student surveys: "effective teaching." The research seeks to determine if there is a difference in how "effective teaching" is defined by those taking student surveys and those interpreting the results. To investigate this difference, a sample group of professors and students…

  12. Dimensions of Teacher Effectiveness

    ERIC Educational Resources Information Center

    Wimberly, Ronald C.; And Others

    1978-01-01

    Describes a study of teacher effectiveness in college departments of sociology, anthropology, and social work. Five types of teacher effectiveness were found to be potentially useful for student, faculty, and administrative purposes. They include teacher task responsiveness, respect for students, teacher capability, student development, and…

  13. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1987-07-01

    As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs.

  14. The polarized EMC effect

    SciTech Connect

    W. Bentz; I. C. Cloet; A. W. Thomas

    2007-02-01

    We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

  15. Organizational Effectiveness of Schools.

    ERIC Educational Resources Information Center

    Miskel, Cecil

    1982-01-01

    Because organizational effectiveness of schools is difficult to define, a model is needed to explain the complexities of the concept. Two models offer some promise. One is the goal model, which defines effectiveness as the degree to which organizations meet or surpass their goals (either official or operational). The other is the system resource…

  16. Developing Effective Managers.

    ERIC Educational Resources Information Center

    Roberts, T.J.

    In this introductory work, the main principles on which British companies are basing management development programs are presented, and stages in assuring a supply of effective managerial talent are set forth: stages in assuring a supply of effective managerial t"lent are set forth: program planning based on clear objectives and communication;…

  17. Correlational effect size benchmarks.

    PubMed

    Bosco, Frank A; Aguinis, Herman; Singh, Kulraj; Field, James G; Pierce, Charles A

    2015-03-01

    Effect size information is essential for the scientific enterprise and plays an increasingly central role in the scientific process. We extracted 147,328 correlations and developed a hierarchical taxonomy of variables reported in Journal of Applied Psychology and Personnel Psychology from 1980 to 2010 to produce empirical effect size benchmarks at the omnibus level, for 20 common research domains, and for an even finer grained level of generality. Results indicate that the usual interpretation and classification of effect sizes as small, medium, and large bear almost no resemblance to findings in the field, because distributions of effect sizes exhibit tertile partitions at values approximately one-half to one-third those intuited by Cohen (1988). Our results offer information that can be used for research planning and design purposes, such as producing better informed non-nil hypotheses and estimating statistical power and planning sample size accordingly. We also offer information useful for understanding the relative importance of the effect sizes found in a particular study in relationship to others and which research domains have advanced more or less, given that larger effect sizes indicate a better understanding of a phenomenon. Also, our study offers information about research domains for which the investigation of moderating effects may be more fruitful and provide information that is likely to facilitate the implementation of Bayesian analysis. Finally, our study offers information that practitioners can use to evaluate the relative effectiveness of various types of interventions. PMID:25314367

  18. Overview of atmospheric effects

    NASA Technical Reports Server (NTRS)

    Rote, D. M.

    1980-01-01

    Effluents from the transportation system are the major cause of Satellite Power System related atmospheric effects. These effects are discussed and include inadvertent weather modification, air quality degradation, compositional changes in the stratosphere and mesosphere, formation of noctilucent clouds, plasma density changes, airglow enhancements, and changes in composition and dynamics of the plasmasphere and magnetosphere.

  19. School Effectiveness and Leadership.

    ERIC Educational Resources Information Center

    Dow, I. I.; Oakley, W. F.

    1992-01-01

    Fiedler's contingency theory relates school effectiveness to a combination of principals' leadership style and situational favorability for the principal. Data from teacher questionnaires on school climate and effectiveness and measures of principal's leadership in 176 Canadian elementary schools did not support Fiedler's model. Contains 54…

  20. Presenting Food Science Effectively

    ERIC Educational Resources Information Center

    Winter, Carl K.

    2016-01-01

    While the need to present food science information effectively is viewed as a critical competency for food scientists by the Institute of Food Technologists, most food scientists may not receive adequate training in this area. Effective presentations combine both scientific content and delivery mechanisms that demonstrate presenter enthusiasm for…

  1. Cardiovascular Effects Of Weightlessness

    NASA Technical Reports Server (NTRS)

    Sandler, Harold

    1992-01-01

    NASA technical memorandum presents study of effects of weightlessness and simulations upon cardiovascular systems of humans and animals. Reviews research up to year 1987 in United States and Soviet space programs on such topics as physiological changes induced by weightlessness in outer space and by subsequent return to Earth gravity and also reviews deconditioning effects of prolonged bed rest on ground.

  2. The Chelate Effect Redefined.

    ERIC Educational Resources Information Center

    da Silva, J. J. R. Frausto

    1983-01-01

    Discusses ambiguities of the accepted definition of the chelate effect, suggesting that it be defined in terms of experimental observation rather than mathematical abstraction. Indicates that the effect depends on free energy change in reaction, ligand basicity, pH of medium, type of chelates formed, and concentration of ligands in solution. (JN)

  3. A ''Voice Inversion Effect?''

    ERIC Educational Resources Information Center

    Bedard, Catherine; Belin, Pascal

    2004-01-01

    Voice is the carrier of speech but is also an ''auditory face'' rich in information on the speaker's identity and affective state. Three experiments explored the possibility of a ''voice inversion effect,'' by analogy to the classical ''face inversion effect,'' which could support the hypothesis of a voice-specific module. Experiment 1 consisted…

  4. Effects on Insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of controlled and modified atmospheres on insects is reviewed and summarized in this chapter. Traditionally, controlled and modified atmospheres are used to store and preserve fresh fruits and vegetables. The effects on insects and the potential of these treatments are secondary to the...

  5. The Kaye Effect

    ERIC Educational Resources Information Center

    Binder, J. M.; Landig, A. J.

    2009-01-01

    The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, "The Kaye effect", as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid…

  6. Music Teacher Effectiveness Research.

    ERIC Educational Resources Information Center

    Brand, Manny

    Although relatively few studies exist, a review of the research reveals some common characteristics of an effective music teacher. Effective music teachers tend to be extroverted, enthusiastic, and care sincerely for their students. Such teachers are competent in musicianship (particularly in diagnosing and correcting musical errors and in using…

  7. PLEIOTROPIC EFFECTS OF STATINS

    PubMed Central

    Liao, James K.; Laufs, Ulrich

    2009-01-01

    Statins are potent inhibitors of cholesterol biosynthesis. In clinical trials, statins are beneficial in the primary and secondary prevention of coronary heart disease. However, the overall benefits observed with statins appear to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering. Indeed, recent studies indicate that some of the cholesterol-independent or “pleiotropic” effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Furthermore, statins have beneficial extrahepatic effects on the immune system, CNS, and bone. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of small GTP-binding proteins, Rho, Ras, and Rac, whose proper membrane localization and function are dependent on isoprenylation, may play an important role in mediating the pleiotropic effects of statins. PMID:15822172

  8. [Psychoanalysis and Side Effect].

    PubMed

    Shirahase, Joichiro

    2015-01-01

    A study of psychoanalysis from the perspective of side effects reveals that its history was a succession of measures to deal with its own side effects. This, however, does not merely suggest that, as a treatment method, psychoanalysis is incomplete and weak: rather, its history is a record of the growth and development of psychoanalysis that discovered therapeutic significance from phenomena that were initially regarded as side effects, made use of these discoveries, and elaborated them as a treatment method. The approach of research seen during the course of these developments is linked to the basic therapeutic approach of psychoanalysis. A therapist therefore does not draw conclusions about a patient's words and behaviors from a single aspect, but continues to make efforts to actively discover a variety of meanings and values from them, and to make the patient's life richer and more productive. This therapeutic approach is undoubtedly one of the unique aspects of psychoanalysis. I discuss the issue of psychoanalysis and side effects with the aim of clarifying this unique characteristic of psychoanalysis. The phenomenon called resistance inevitably emerges during the process of psychoanalytic treatment. Resistance can not only obstruct the progress of therapy; it also carries the risk of causing a variety of disadvantages to the patient. It can therefore be seen as an adverse effect. However, if we re-examine this phenomenon from the perspective of transference, we find that resistance is in fact a crucial tool in psychoanalysis, and included in its main effect, rather than a side effect. From the perspective of minimizing the character of resistance as a side effect and maximizing its character as a main effect, I have reviewed logical organization, dynamic evaluation, the structuring of treatment, the therapist's attitudes, and the training of therapists. I conclude by stating that psychoanalysis has aspects that do not match the perspective known as a side

  9. Cardiovascular Effects of Felypressin

    PubMed Central

    Cecanho, Rodrigo; De Luca, Laurival Antonio; Ranali, José

    2006-01-01

    Cardiovascular effects of felypressin (FEL) were studied in Wistar rats. Heart rate and mean arterial pressure measurements were taken in awake rats treated with vasopressin (AVP), FEL, or epinephrine (EPI). Each group received either an intravenous (IV) or an intracerebroventricular V1 receptor antagonist, saline, area postrema removal, or sham surgery. Analysis of variance and Student-Newman-Keuls (P < .05) were applied. Felypressin and AVP induced a pressor effect, and bradycardia was inhibited by IV V1 antagonist. Intracerebroventricular V1 antagonist and area postrema removal enhanced their pressor effects. Epinephrine induced a higher pressor effect and a similar bradycardia that was not affected by the treatments. It was concluded that FEL depends on V1 receptors to induce pressor and bradycardic effects, and that it produces a high relationship between bradycardia and mean arterial pressure variation depending on area postrema and central V1 receptors. These effects are potentially less harmful to the cardiovascular system than the effects of EPI. PMID:17177590

  10. Nonlocal Anomalous Hall Effect

    NASA Astrophysics Data System (ADS)

    Zhang, Steven S.-L.; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.

  11. Use of effective dose.

    PubMed

    Harrison, J D; Balonov, M; Martin, C J; Ortiz Lopez, P; Menzel, H-G; Simmonds, J R; Smith-Bindman, R; Wakeford, R

    2016-06-01

    International Commission on Radiological Protection (ICRP) Publication 103 provided a detailed explanation of the purpose and use of effective dose and equivalent dose to individual organs and tissues. Effective dose has proven to be a valuable and robust quantity for use in the implementation of protection principles. However, questions have arisen regarding practical applications, and a Task Group has been set up to consider issues of concern. This paper focusses on two key proposals developed by the Task Group that are under consideration by ICRP: (1) confusion will be avoided if equivalent dose is no longer used as a protection quantity, but regarded as an intermediate step in the calculation of effective dose. It would be more appropriate for limits for the avoidance of deterministic effects to the hands and feet, lens of the eye, and skin, to be set in terms of the quantity, absorbed dose (Gy) rather than equivalent dose (Sv). (2) Effective dose is in widespread use in medical practice as a measure of risk, thereby going beyond its intended purpose. While doses incurred at low levels of exposure may be measured or assessed with reasonable reliability, health effects have not been demonstrated reliably at such levels but are inferred. However, bearing in mind the uncertainties associated with risk projection to low doses or low dose rates, it may be considered reasonable to use effective dose as a rough indicator of possible risk, with the additional consideration of variation in risk with age, sex and population group. PMID:26980800

  12. Bustling argon: biological effect

    PubMed Central

    2013-01-01

    Argon is a noble gas in group 18 of the periodic table. Certificated to exist in air atmosphere merely one century ago, discovery of argon shows interesting stories of researching and exploring. It was assumed to have no chemical activity. However, argon indeed present its biological effect on mammals. Narcotic effect of argon in diving operation and neur-protective function of argon in cerebral injury demonstrate that argon has crucial effect and be concentrated on is necessary. Furthermore, consider to be harmless to human, argon clinical application in therapy would be another option. PMID:24088583

  13. Improving engineering effectiveness

    NASA Technical Reports Server (NTRS)

    Fiero, J. D.

    1985-01-01

    Methodologies to improve engineering productivity were investigated. The rocky road to improving engineering effectiveness is reviewed utilizing a specific semiconductor engineering organization as a case study. The organization had a performance problem regarding new product introductions. With the help of this consultant as a change agent the engineering team used a systems approach to through variables that were effecting their output significantly. Critical factors for improving this engineering organization's effectiveness and the roles/responsibilities of management, the individual engineers and the internal consultant are discussed.

  14. Cardiovascular Effects of Weightlessness

    NASA Technical Reports Server (NTRS)

    Short, K.

    1985-01-01

    Physiological changes resulting from long term weightlessness are reviewed and activities conducted to study cardiovascular deconditioning at NASA Ames are discussed. Emphasis is on using monkeys in chair rest, water immersion, and tilt table studies to simulate space environment effects.

  15. Coefficients of Effective Length.

    ERIC Educational Resources Information Center

    Edwards, Roger H.

    1981-01-01

    Under certain conditions, a validity Coefficient of Effective Length (CEL) can produce highly misleading results. A modified coefficent is suggested for use when empirical studies indicate that underlying assumptions have been violated. (Author/BW)

  16. Effects of New Technologies.

    ERIC Educational Resources Information Center

    Social and Labour Bulletin, 1980

    1980-01-01

    Transnational implications of technological change and innovation in telecommunications are discussed, including impact on jobs and industrial relations, computer security, access to information, and effects of technological innovation on international economic systems. (SK)

  17. Hydrodynamic effects in proteins

    NASA Astrophysics Data System (ADS)

    Szymczak, Piotr; Cieplak, Marek

    2011-01-01

    Experimental and numerical results pertaining to flow-induced effects in proteins are reviewed. Special emphasis is placed on shear-induced unfolding and on the role of solvent mediated hydrodynamic interactions in the conformational transitions in proteins.

  18. Hydrodynamic effects in proteins.

    PubMed

    Szymczak, Piotr; Cieplak, Marek

    2011-01-26

    Experimental and numerical results pertaining to flow-induced effects in proteins are reviewed. Special emphasis is placed on shear-induced unfolding and on the role of solvent mediated hydrodynamic interactions in the conformational transitions in proteins. PMID:21406855

  19. Cytogenetic effects of cyclamates

    SciTech Connect

    Jemison, E.W.; Brown, K.; Rivers, B.; Knight, R.

    1984-01-01

    PHA-stimulated human peripheral lymphocytes were used as a model system for assessing the in vitro effects of calcium cyclamate. Techniques of autoradiography, cytological staining, cell counting, liquid scintillation and karyotyping were used to study the cytogenetic damage and biochemical effects of calcium cyclamate when assayed in 24 hour intervals for 96 hours. The cells were exposed to 10(-2) and 10(-3) molar concentrations of calcium cyclamate in TC 199 medium with fetal calf serum and antibiotics. It was noted that the addition of cyclamate increased mitotic rate of lymphocyte cells in cultures. It was determined that calcium cyclamate impaired the synthesis of deoxribonunucleic acid (as depicted by decreased incorporation of tritiated thymidine), reduced grain counts in autoradiographs and increased chromosome aberrations in cyclamate treated PHA stimulated peripheral blood lymphocytes in vitro. Morphological changes and growth rates showed significant effects. These studies indicate that calcium cyclamate has variable significant effects on leucocytes growth and chromosome morphology.

  20. Effects of Anesthesia

    MedlinePlus

    ... you or your family member has ever had heat stroke, or suffered from the condition in a previous surgery, be sure to tell the physician anesthesiologist. Regional Anesthesia The potential side effects of regional anesthesia (such as an epidural or ...

  1. Comparative effectiveness research.

    PubMed

    Hirsch, J A; Schaefer, P W; Romero, J M; Rabinov, J D; Sanelli, P C; Manchikanti, L

    2014-09-01

    The goal of comparative effectiveness research is to improve health care while dealing with the seemingly ever-rising cost. An understanding of comparative effectiveness research as a core topic is important for neuroradiologists. It can be used in a variety of ways. Its goal is to look at alternative methods of interacting with a clinical condition, ideally, while improving delivery of care. While the Patient-Centered Outcome Research initiative is the most mature US-based foray into comparative effectiveness research, it has been used more robustly in decision-making in other countries for quite some time. The National Institute for Health and Clinical Excellence of the United Kingdom is a noteworthy example of comparative effectiveness research in action. PMID:24874531

  2. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1986-01-01

    The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented. (ACR)

  3. Evaluating teaching effectiveness.

    PubMed

    Kirschling, J M; Fields, J; Imle, M; Mowery, M; Tanner, C A; Perrin, N; Stewart, B J

    1995-12-01

    Major reform in nursing education is underway, with increased emphasis being placed on the importance of the teacher-student relationship. An instrument for evaluation of teaching effectiveness, developed at the Oregon Health Sciences University School of Nursing, attempts to capture the student's perception of the quality of the teacher-student relationship as well as other salient aspects of teaching practices. The evaluation tool contains 26 items evaluating teaching effectiveness and 14 items that evaluate the course. The teaching effectiveness items yield five scales including: knowledge and expertise, facilitative teaching methods, communication style, use of own experiences, and feedback. Psychometric testing has been completed and there is evidence of construct validity in relation to teaching effectiveness and internal consistency reliability for the five scales. PMID:8583255

  4. Side Effects of Chemotherapy

    MedlinePlus

    ... reactions to the different drugs. The doctors, nurses, and pharmacists will describe what to look out for in ... will be monitored very closely by doctors, nurses, and pharmacists to make sure that all side effects are ...

  5. Systems effectiveness evaluation program

    NASA Technical Reports Server (NTRS)

    Nicely, H. P., Jr.; Givens, W. D.

    1972-01-01

    Eight integrated computer programs provide needed capability to reduce man-hours needed to perform routine monitoring and assessment of effectiveness, reliability, and maintainability of large electronic equipment systems.

  6. Health Effects of Tsunamis

    MedlinePlus

    ... on Specific Types of Emergencies Health Effects of Tsunamis Language: English Español (Spanish) Recommend on Facebook Tweet ... environmental hazards. The majority of deaths associated with tsunamis are related to drownings, but traumatic injuries are ...

  7. Pictorial Superiority Effect

    ERIC Educational Resources Information Center

    Nelson, Douglas L.; And Others

    1976-01-01

    Pictures generally show superior recognition relative to their verbal labels. This experiment was designed to link this pictorial superiority effect to sensory or meaning codes associated with the two types of symbols. (Editor)

  8. [Genetic effects of radiation].

    PubMed

    Nakamura, Nori

    2012-03-01

    This paper is a short review of genetic effect of radiation. This includes methods and results of a large-scale genetic study on specific loci in mice and of various studies in the offspring of atomic-bomb survivors. As for the latter, there is no results obtained which suggest the effect of parental exposure to radiation. Further, in recent years, studies are conducted to the offspring born to parents who were survivors of childhood cancers. In several reports, the mean gonad dose is quite large whereas in most instances, the results do not indicate genetic effect following parental exposure to radiation. Possible reasons for the difficulties in detecting genetic effect of radiation are discussed. PMID:22514926

  9. Modulational effects in accelerators

    SciTech Connect

    Satogata, T.

    1997-12-01

    We discuss effects of field modulations in accelerators, specifically those that can be used for operational beam diagnostics and beam halo control. In transverse beam dynamics, combined effects of nonlinear resonances and tune modulations influence diffusion rates with applied tune modulation has been demonstrated. In the longitudinal domain, applied RF phase and voltage modulations provide mechanisms for parasitic halo transport, useful in slow crystal extraction. Experimental experiences with transverse tune and RF modulations are also discussed.

  10. Secondary pool boiling effects

    NASA Astrophysics Data System (ADS)

    Kruse, C.; Tsubaki, A.; Zuhlke, C.; Anderson, T.; Alexander, D.; Gogos, G.; Ndao, S.

    2016-02-01

    A pool boiling phenomenon referred to as secondary boiling effects is discussed. Based on the experimental trends, a mechanism is proposed that identifies the parameters that lead to this phenomenon. Secondary boiling effects refer to a distinct decrease in the wall superheat temperature near the critical heat flux due to a significant increase in the heat transfer coefficient. Recent pool boiling heat transfer experiments using femtosecond laser processed Inconel, stainless steel, and copper multiscale surfaces consistently displayed secondary boiling effects, which were found to be a result of both temperature drop along the microstructures and nucleation characteristic length scales. The temperature drop is a function of microstructure height and thermal conductivity. An increased microstructure height and a decreased thermal conductivity result in a significant temperature drop along the microstructures. This temperature drop becomes more pronounced at higher heat fluxes and along with the right nucleation characteristic length scales results in a change of the boiling dynamics. Nucleation spreads from the bottom of the microstructure valleys to the top of the microstructures, resulting in a decreased surface superheat with an increasing heat flux. This decrease in the wall superheat at higher heat fluxes is reflected by a "hook back" of the traditional boiling curve and is thus referred to as secondary boiling effects. In addition, a boiling hysteresis during increasing and decreasing heat flux develops due to the secondary boiling effects. This hysteresis further validates the existence of secondary boiling effects.

  11. "Side" effects: a misnomer.

    PubMed Central

    Joyce, C. R.

    1976-01-01

    The tragic results for the babies of patients prescribed thalidomide, although they can indeed be termed "side" effects, hardly warrant so slight an epithet, and Dr Joyce in his paper would like the term to be dropped in favour of "additional" effects of drugs. Despite extensive clinical trials before drugs are put before the prescribing doctor, side effects cannot be entirely anticipated or eliminated, and indeed many are not harmful. However, it is important, Dr Joyce argues, for information to the doctor from the patient and from the doctor to the manufacturer to be collected and evaluated. Only in this way can effects of drugs other than those intended be drawn to the notice of the manufacturer. The commentary by two practising physicians emphasizes the ambiguities in the descriptive literature accompanying a new drug. Dr Herxheimer and Dr Higgs would like to see some sort of panel to be established to reassess drugs in the light of observations on their effects and "side" effects on patients, a task which the existing Committee on Safety of Medicines could not at the moment undertake. A medical need for a new drug should be established before it is manufactured, let alone offered to the general practitioner. PMID:823336

  12. Effective Transport Properties

    NASA Astrophysics Data System (ADS)

    Mauri, Roberto

    In this chapter we study a particular case of multiphase systems, namely two-phase materials in which one of the phases is randomly dispersed in the other, so that the composite can be viewed on a macroscale as an effective continuum, with well defined properties. In general, the theoretical determination of the parameter for an effective medium requires, as a rule, the solution of a corresponding transport problem at the microscale, which takes into account the morphology of the system and its evolution. As the mathematical problem is well-posed on a microscale, this can be accomplished using, for example, the multiple scale approach shown in Chap. 11 ; however, the task requires massive computations and is therefore difficult to implement from the practical standpoint. Here, instead, we focus on a deterministic approach to the problem, where the geometry and spatial configuration of the particles comprising the included phase are given and the solution to the microscale problem is therefore sought analytically. As examples, we study the effective thermal conductivity of solid reinforced materials (Sect. 10.1), the effective viscosity of non-colloidal suspensions (Sect. 10.2), the effective permeability of porous materials (10.3) and the effective self- and gradient diffusivities of colloidal suspensions (Sect. 10.4). Then, in Sect. 10.5, an alternative dynamic definition of the transport coefficients is considered, which can also serve as a basis to determine the effective properties of complex systems.

  13. Spin Hall effects

    NASA Astrophysics Data System (ADS)

    Sinova, Jairo; Valenzuela, Sergio O.; Wunderlich, J.; Back, C. H.; Jungwirth, T.

    2015-10-01

    Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical

  14. The negative repetition effect.

    PubMed

    Mulligan, Neil W; Peterson, Daniel J

    2013-09-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising negative repetition effect, in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and across pairs, the target words were drawn from a small set of categories. In the repetition condition, the pairs were initially presented in a random order and then presented a 2nd time blocked by the category of the target words. In the single presentation condition, the pairs were presented only in the blocked order. Participants in the former condition recalled fewer target words on a free recall test despite having seen the word pairs twice (the negative repetition effect). This phenomenon is explored in a series of 5 experiments assessing 3 theoretical accounts of the effect. The experiments demonstrate that the negative repetition effect generalizes over multiple encoding conditions (reading and generative encoding), over different memory tests (free and cued recall), and over delay (5 min and 2 days). The results argue against a retrieval account and a levels-of-processing account but are consistent with the item-specific-relational account, the account upon which the effect was initially predicated. PMID:23421508

  15. Mitochondrial threshold effects.

    PubMed Central

    Rossignol, Rodrigue; Faustin, Benjamin; Rocher, Christophe; Malgat, Monique; Mazat, Jean-Pierre; Letellier, Thierry

    2003-01-01

    The study of mitochondrial diseases has revealed dramatic variability in the phenotypic presentation of mitochondrial genetic defects. To attempt to understand this variability, different authors have studied energy metabolism in transmitochondrial cell lines carrying different proportions of various pathogenic mutations in their mitochondrial DNA. The same kinds of experiments have been performed on isolated mitochondria and on tissue biopsies taken from patients with mitochondrial diseases. The results have shown that, in most cases, phenotypic manifestation of the genetic defect occurs only when a threshold level is exceeded, and this phenomenon has been named the 'phenotypic threshold effect'. Subsequently, several authors showed that it was possible to inhibit considerably the activity of a respiratory chain complex, up to a critical value, without affecting the rate of mitochondrial respiration or ATP synthesis. This phenomenon was called the 'biochemical threshold effect'. More recently, quantitative analysis of the effects of various mutations in mitochondrial DNA on the rate of mitochondrial protein synthesis has revealed the existence of a 'translational threshold effect'. In this review these different mitochondrial threshold effects are discussed, along with their molecular bases and the roles that they play in the presentation of mitochondrial diseases. PMID:12467494

  16. A "voice inversion effect?".

    PubMed

    Bédard, Catherine; Belin, Pascal

    2004-07-01

    Voice is the carrier of speech but is also an "auditory face" rich in information on the speaker's identity and affective state. Three experiments explored the possibility of a "voice inversion effect," by analogy to the classical "face inversion effect," which could support the hypothesis of a voice-specific module. Experiment 1 consisted of a gender identification task on two syllables pronounced by 90 speakers (boys, girls, men, and women). Experiment 2 consisted of a speaker discrimination task on pairs of syllables (8 men and 8 women). Experiment 3 consisted of an instrument discrimination task on pairs of melodies (8 string and 8 wind instruments). In all three experiments, stimuli were presented in 4 conditions: (1) no inversion; (2) temporal inversion (e.g., backwards speech); (3) frequency inversion centered around 4000 Hz; and (4) around 2500 Hz. Results indicated a significant decrease in performance caused by sound inversion, with a much stronger effect for frequency than for temporal inversion. Interestingly, although frequency inversion markedly affected timbre for both voices and instruments, subjects' performance was still above chance. However, performance at instrument discrimination was much higher than for voices, preventing comparison of inversion effects for voices vs. non-vocal stimuli. Additional experiments will be necessary to conclude on the existence of a possible "voice inversion effect." PMID:15177788

  17. Pleiotropic effects of statins

    PubMed Central

    Kavalipati, Narasaraju; Shah, Jay; Ramakrishan, Ananthraman; Vasnawala, Hardik

    2015-01-01

    Statins or 3-hydroxy-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors not only prevents the synthesis of cholesterol biosynthesis but also inhibits the synthesis of essential isoprenoid intermediates such as farnesyl pyrophosphate, geranylgeranyl pyrophosphate, isopentanyl adenosine, dolichols and polyisoprenoid side chains of ubiquinone, heme A, and nuclear lamins. These isoprenoid intermediates are required for activation of various intracellular/signaling proteins- small guanosine triphosphate bound protein Ras and Ras-like proteins like Rho, Rab, Rac, Ral, or Rap which plays an indispensible role in multiple cellular processes. Reduction of circulating isoprenoids intermediates as a result of HMG CoA reductase inhibition by statins prevents activation of these signalling proteins. Hence, the multiple effects of statins such as antiinflammatory effects, antioxidant effects, antiproliferative and immunomodulatory effects, plaque stability, normalization of sympathetic outflow, and prevention of platelet aggregation are due to reduction of circulating isoprenoids and hence inactivation of signalling proteins. These multiple lipid-independent effects of statins termed as statin pleiotropy would potentially open floodgates for research in multiple treatment domains catching attentions of researchers and clinician across the globe. PMID:26425463

  18. Effective Nutritional Supplement Combinations

    NASA Astrophysics Data System (ADS)

    Cooke, Matt; Cribb, Paul J.

    Few supplement combinations that are marketed to athletes are supported by scientific evidence of their effectiveness. Quite often, under the rigor of scientific investigation, the patented combination fails to provide any greater benefit than a group given the active (generic) ingredient. The focus of this chapter is supplement combinations and dosing strategies that are effective at promoting an acute physiological response that may improve/enhance exercise performance or influence chronic adaptations desired from training. In recent years, there has been a particular focus on two nutritional ergogenic aids—creatine monohydrate and protein/amino acids—in combination with specific nutrients in an effort to augment or add to their already established independent ergogenic effects. These combinations and others are discussed in this chapter.

  19. Cyclone vibration effects

    SciTech Connect

    Gray, D.C.; Tillery, M.I.

    1981-09-01

    A Government Accounting Office review of coal mine dust sampling procedures recommended studies be performed to determine accuracy and precision of dust measurements taken with current equipment. The effects of vibration on the 10-mm Dorr-Oliver nylon cyclone run at a flow rate of 2 L/min were investigated. A total of 271 samples were taken during 95 tests. All tests lasted about 7 h each and were performed inside a 19 l capacity aerosol chamber. Coal dust concentrations of about 2 mg/m/SUP/3 in air and a respirable fraction of 25-30% were used. The effects of a variety of vibration frequencies and stroke lengths were tested in two modes (horizontal and vertical). At most frequencies and stroke lengths, vibration was found to have an insignificant effect on cyclone performance.

  20. Transgenerational genetic effects

    PubMed Central

    Nelson, Vicki R; Nadeau, Joseph H

    2012-01-01

    Since Mendel, studies of phenotypic variation and disease risk have emphasized associations between genotype and phenotype among affected individuals in families and populations. Although this paradigm has led to important insights into the molecular basis for many traits and diseases, most of the genetic variants that control the inheritance of these conditions continue to elude detection. Recent studies suggest an alternative mode of inheritance where genetic variants that are present in one generation affect phenotypes in subsequent generations, thereby decoupling the conventional relations between genotype and phenotype, and perhaps, contributing to ‘missing heritability’. Under some conditions, these transgenerational genetic effects can be as frequent and strong as conventional inheritance, and can persist for multiple generations. Growing evidence suggests that RNA mediates these heritable epigenetic changes. The primary challenge now is to identify the molecular basis for these effects, characterize mechanisms and determine whether transgenerational genetic effects occur in humans. PMID:22122083

  1. Aviation noise effects

    NASA Astrophysics Data System (ADS)

    Newman, J. S.; Beattie, K. R.

    1985-03-01

    This report summarizes the effects of aviation noise in many areas, ranging from human annoyance to impact on real estate values. It also synthesizes the findings of literature on several topics. Included in the literature were many original studies carried out under FAA and other Federal funding over the past two decades. Efforts have been made to present the critical findings and conclusions of pertinent research, providing, when possible, a bottom line conclusion, criterion or perspective. Issues related to aviation noise are highlighted, and current policy is presented. Specific topic addressed include: annoyance; Hearing and hearing loss; noise metrics; human response to noise; speech interference; sleep interference; non-auditory health effects of noise; effects of noise on wild and domesticated animals; low frequency acoustical energy; impulsive noise; time of day weightings; noise contours; land use compatibility; and real estate values. This document is designed for a variety of users, from the individual completely unfamiliar with aviation noise to experts in the field.

  2. Effective Documentation Tools

    NASA Technical Reports Server (NTRS)

    Sleboda, Claire

    1997-01-01

    Quality assurance programs provide a very effective means to monitor and evaluate medical care. Quality assurance involves: (1) Identify a problem; (2) Determine the source and nature of the problem; (3) Develop policies and methods to effect improvement; (4) Implement those polices; (5) Monitor the methods applied; and (6) Evaluate their effectiveness. Because this definition of quality assurance so closely resembles the Nursing Process, the health unit staff was able to use their knowledge of the nursing process to develop many forms which improve the quality of patient care. These forms include the NASA DFRC Service Report, the occupational injury form (Incident Report), the patient survey (Pre-hospital Evaluation/Care Report), the Laboratory Log Sheet, the 911 Run Sheet, and the Patient Assessment Stamp. Examples and steps which are followed to generate these reports are described.

  3. Cosmological memory effect

    NASA Astrophysics Data System (ADS)

    Tolish, Alexander; Wald, Robert M.

    2016-08-01

    The "memory effect" is the permanent change in the relative separation of test particles resulting from the passage of gravitational radiation. We investigate the memory effect for a general, spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology by considering the radiation associated with emission events involving particle-like sources. We find that if the resulting perturbation is decomposed into scalar, vector, and tensor parts, only the tensor part contributes to memory. Furthermore, the tensor contribution to memory depends only on the cosmological scale factor at the source and observation events, not on the detailed expansion history of the universe. In particular, for sources at the same luminosity distance, the memory effect in a spatially flat FLRW spacetime is enhanced over the Minkowski case by a factor of (1 +z ).

  4. Relative age effect: implications for effective practice.

    PubMed

    Andronikos, Georgios; Elumaro, Adeboye Israel; Westbury, Tony; Martindale, Russell J J

    2016-06-01

    Physical and psychological differences related to birthdate amongst athletes of the same selection year have been characterised as the "relative age effects" (RAEs). RAEs have been identified in a variety of sports, both at youth and adult level, and are linked with dropout of athletes and a reduction of the talent pool. This study examined the existence, mechanisms and possible solutions to RAEs using qualitative methodology. Seven experts in the field of talent identification and development were interviewed. Inductive analysis of the data showed that, while there was mixed evidence for the existence of RAEs across sports, the eradication of RAEs was attributed to controllable features of the development environment. The factors reported included the structure of "categories" used to group athletes within the sport (e.g. age, weight, size, skills), recognition and prioritisation of long-term development over "short term win focus." Education of relevant parties (e.g. coaches, scouts, clubs) about RAEs and the nature of "talent" within a long-term context was suggested, along with careful consideration of the structure of the development environment (e.g. delayed selection, provision for late developers, focus on skills not results, use of challenge). Implications for research and practice are discussed. PMID:26417709

  5. Habituation of reinforcer effectiveness.

    PubMed

    Lloyd, David R; Medina, Douglas J; Hawk, Larry W; Fosco, Whitney D; Richards, Jerry B

    2014-01-01

    In this paper we propose an integrative model of habituation of reinforcer effectiveness (HRE) that links behavioral- and neural-based explanations of reinforcement. We argue that HRE is a fundamental property of reinforcing stimuli. Most reinforcement models implicitly suggest that the effectiveness of a reinforcer is stable across repeated presentations. In contrast, an HRE approach predicts decreased effectiveness due to repeated presentation. We argue that repeated presentation of reinforcing stimuli decreases their effectiveness and that these decreases are described by the behavioral characteristics of habituation (McSweeney and Murphy, 2009; Rankin etal., 2009). We describe a neural model that postulates a positive association between dopamine neurotransmission and HRE. We present evidence that stimulant drugs, which artificially increase dopamine neurotransmission, disrupt (slow) normally occurring HRE and also provide evidence that stimulant drugs have differential effects on operant responding maintained by reinforcers with rapid vs. slow HRE rates. We hypothesize that abnormal HRE due to genetic and/or environmental factors may underlie some behavioral disorders. For example, recent research indicates that slow-HRE is predictive of obesity. In contrast ADHD may reflect "accelerated-HRE." Consideration of HRE is important for the development of effective reinforcement-based treatments. Finally, we point out that most of the reinforcing stimuli that regulate daily behavior are non-consumable environmental/social reinforcers which have rapid-HRE. The almost exclusive use of consumable reinforcers with slow-HRE in pre-clinical studies with animals may have caused the importance of HRE to be overlooked. Further study of reinforcing stimuli with rapid-HRE is needed in order to understand how habituation and reinforcement interact and regulate behavior. PMID:24409128

  6. Effective Temperature of Mutations

    NASA Astrophysics Data System (ADS)

    Derényi, Imre; Szöllősi, Gergely J.

    2015-02-01

    Biological macromolecules experience two seemingly very different types of noise acting on different time scales: (i) point mutations corresponding to changes in molecular sequence and (ii) thermal fluctuations. Examining the secondary structures of a large number of microRNA precursor sequences and model lattice proteins, we show that the effects of single point mutations are statistically indistinguishable from those of an increase in temperature by a few tens of kelvins. The existence of such an effective mutational temperature establishes a quantitative connection between robustness to genetic (mutational) and environmental (thermal) perturbations.

  7. Modeling Hofmeister Effects.

    PubMed

    Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A

    2009-03-11

    A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

  8. Modeling Hofmeister Effects

    PubMed Central

    Hribar-Lee, Barbara; Vlachy, Vojko; Dill, Ken A.

    2009-01-01

    A two dimensional model of water, so-called Mercedes-Benz model, was used to study effects of the size of hydrophobic solute on the insertion thermodynamics in electrolyte solutions. The model was examined by the constant pressure Monte Carlo computer simulation. The results were compared with the experimental data for noble gasses and methane in water and electrolyte solution. The influence of different ions at infinite dilution on the free energy of transfer was explored. Qualitative agreement with the experimental results was obtained. The mechanism of Hofmeister effects was proposed. PMID:20161468

  9. Quantum Spin Hall Effect

    SciTech Connect

    Bernevig, B.Andrei; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-01-15

    The quantum Hall liquid is a novel state of matter with profound emergent properties such as fractional charge and statistics. Existence of the quantum Hall effect requires breaking of the time reversal symmetry caused by an external magnetic field. In this work, we predict a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2 e/4{pi}. The degenerate quantum Landau levels are created by the spin-orbit coupling in conventional semiconductors in the presence of a strain gradient. This new state of matter has many profound correlated properties described by a topological field theory.

  10. Magnetic Nernst effect

    NASA Astrophysics Data System (ADS)

    Brechet, Sylvain D.; Ansermet, Jean-Philippe

    2015-09-01

    The thermodynamics of irreversible processes in continuous media predicts the existence of a magnetic Nernst effect that results from a magnetic analog to the Seebeck effect in a ferromagnet and magnetophoresis occurring in a paramagnetic electrode in contact with the ferromagnet. Thus, a voltage that has DC and AC components is expected across a Pt electrode as a response to the inhomogeneous magnetic induction field generated by magnetostatic waves of an adjacent YIG slab subject to a temperature gradient. The voltage frequency and dependence on the orientation of the applied magnetic induction field are quite distinct from that of spin pumping.

  11. [Cytoprotective effects of bilirubin].

    PubMed

    Vítek, L

    2005-01-01

    Bilirubin, a major product of heme catabolism, belongs to compounds with pleiotropic biologic effects. For a long time bilirubin was considered as a metabolite dangerous for human health, neonatologists know well serious clinical complication of neonatal jaundice called bilirubin encephalopathy. Nevertheless, recent data has demonstrated that bilirubin exhibits potent antioxidant and even anti-inflammatory effects with substantial clinical impacts. The aim of the present study was to summarize present knowledge in this rapidly evolving field and suggest further possible clinical consequences. PMID:15981989

  12. Photostimulated even acoustoelectric effect

    NASA Astrophysics Data System (ADS)

    Shmelev, G. M.; Shon, N. Kh.; Tsurkan, G. I.

    1985-02-01

    Photostimulated photogalvanic (PG) and acoustogalvanic (AG) currents in a semiconductor placed in the field of two linearly polarized electromagnetic waves with frequencies Omega sub 1 = 2Omega sub 2 are analyzed. These currents affect the probability of electron scattering and the HF acoustic flux field. Under specified double laser illumination the system comprising an electron gas and photons becomes noncentrosymmetric, which leads to the PG and AG effects. The AG effect represents a contribution to the acoustoelectric current that is linear according to intensity and even according to the acoustic wave vector.

  13. Enhancing board effectiveness.

    PubMed

    Curran, Connie R; Totten, Mary K

    2010-01-01

    Like any other job, board work is associated with specific competencies. Competencies are the combination of knowledge, skills, personal characteristics, and behaviors needed to perform a job or task effectively. Boards are only as strong as their weakest member. Board education should focus on improving the knowledge and skills of the board and individual members and on overall board performance. Assessment of individual board member performance is designed to evaluate the trustee's knowledge of board roles and responsibilities and the expectations of board members. Board effectiveness is built through competency-based board member recruitment and selection; board member education and development; and evaluation of board, board member, and meeting performance. PMID:21291066

  14. Nonequilibrium effects in Isoscaling

    SciTech Connect

    Dorso, C. O.; Lopez, J. A.

    2007-02-12

    In this work we study within a simple model different properties of the system that allow us to understand the properties of the isoscaling observable. We first show that isoscaling is a general property of fragmenting systems. We show this by using a simple generalized percolation model. We show that the usual isoscaling property can be obtained in the case of bond percolation in bichromatic lattices with any regular topology. In this case the probabilities of each color (isospin) are independent. We then explore the effect of introducing 'non-equilibrium' effects.

  15. Contamination effects study

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The in-situ optical surface measurement system is a facility designed to study the deleterious effects of particulate materials on the surface reflectivities of optical materials in the vacuum ultraviolet (VUV). This arrangement is designed to simulate the on-orbit effects of contamination and degradation of optical surfaces. This simulation is accomplished through the use of non-coherent VUV sources illuminating optical surfaces located in a high vacuum chamber. Several sources of contamination are employed. The reflectivity is measured both at the specular reflection as well as at two scattered positions, forward and reverse. The system components are described and an operating procedure is given.

  16. Global phase diagram and single particle excitations in Kondo insulators

    NASA Astrophysics Data System (ADS)

    Si, Qimiao; Pixley, Jedediah; Yu, Rong; Paschen, Silke

    Motivated by quantum criticality in Kondo insulators tuned by pressure or doping we study the effects of magnetic frustration and the properties of the single particle excitations in a Kondo lattice model. Focusing on the Kondo insulating limit we study the Shastry-Sutherland Kondo lattice and determine the zero temperature phase diagram, which incorporates a valence bond solid, antiferromagnet, and Kondo insulating ground states, with metal-to-insulator quantum phase transitions. We argue that this phase diagram is generic and represents a ``global'' phase diagram of Kondo insulators in terms of quantum fluctuations and the Kondo interaction. We then focus on the momentum distribution of single particle excitations within the Kondo insulating ground state. We show how features of the Fermi-surface of the underlying conduction electrons appear in the Kondo insulating phase. Lastly, we discuss the implications of our results for quantum criticality in Kondo insulators as well as for the recent de Haas-von Alphen measurements in the Kondo insulator SmB6.

  17. Positron annihilation study of the electronic structure of LaB{sub 6} and CeB{sub 6}

    SciTech Connect

    Biasini, M.; Fretwell, H.M.; Dugdale, S.B.; Alam, M.A.; Kubo, Y.; Harima, H.; Sato, N.

    1997-10-01

    We measured the two-dimensional angular correlation of the positron annihilation radiation (2D-ACAR) on a single crystal of LaB{sub 6} for two projections. The anisotropies of the 2D electron-positron momentum density were very similar to those observed for the isostructural heavy-fermion (HF) system CeB{sub 6} in the paramagnetic phase and consistent with those of the calculated electron-positron momentum density of LaB{sub 6}. The standard Lock-Crisp-West (LCW) analysis was in reasonable agreement with the LCW folding of the calculated 2D-ACAR spectrum and the de Haas{endash}van Alphen findings. From the projected {bold {ital k}}-space density we could evaluate the Fermi volume, corresponding to 1.10{plus_minus}0.04 electrons per formula unit, and deduce that the effect of the nonuniform positron density does not play a significant role. The apparent discrepancy with the LCW analysis of CeB{sub 6}, where filtering procedures were required to recover a k-space density similar to that obtained for LaB{sub 6}, is discussed. {copyright} {ital 1997} {ital The American Physical Society}

  18. Fermi surface reconstruction and multiple quantum phase transitions in the antiferromagnet CeRhIn5

    PubMed Central

    Jiao, Lin; Chen, Ye; Kohama, Yoshimitsu; Graf, David; Bauer, E. D.; Singleton, John; Zhu, Jian-Xin; Weng, Zongfa; Pang, Guiming; Shang, Tian; Zhang, Jinglei; Lee, Han-Oh; Park, Tuson; Jaime, Marcelo; Thompson, J. D.; Steglich, Frank; Si, Qimiao; Yuan, H. Q.

    2015-01-01

    Conventional, thermally driven continuous phase transitions are described by universal critical behavior that is independent of the specific microscopic details of a material. However, many current studies focus on materials that exhibit quantum-driven continuous phase transitions (quantum critical points, or QCPs) at absolute zero temperature. The classification of such QCPs and the question of whether they show universal behavior remain open issues. Here we report measurements of heat capacity and de Haas–van Alphen (dHvA) oscillations at low temperatures across a field-induced antiferromagnetic QCP (Bc0 ≈ 50 T) in the heavy-fermion metal CeRhIn5. A sharp, magnetic-field-induced change in Fermi surface is detected both in the dHvA effect and Hall resistivity at B0* ≈ 30 T, well inside the antiferromagnetic phase. Comparisons with band-structure calculations and properties of isostructural CeCoIn5 suggest that the Fermi-surface change at B0* is associated with a localized-to-itinerant transition of the Ce-4f electrons in CeRhIn5. Taken in conjunction with pressure experiments, our results demonstrate that at least two distinct classes of QCP are observable in CeRhIn5, a significant step toward the derivation of a universal phase diagram for QCPs. PMID:25561536

  19. Fermi surface of the ferromagnetic semimetal, EuB{sub 6}

    SciTech Connect

    Aronson, M.C.; Sarrao, J.L.; Fisk, Z.; Whitton, M.; Brandt, B.L.

    1999-02-01

    We report the results of magnetoresistance and magnetization measurements on single crystal EuB{sub 6} for temperatures above and below the ferromagnetic ordering temperatures T{sub C}{sup +}=15.3 K and T{sub C}{sup {minus}}=12.5 K, in magnetic fields as large as 30 T. Shubnikov{endash}de Haas and de Haas{endash}van Alphen oscillations were observed with four fundamental frequencies. By comparison to band-structure calculations, we ascribe the orbits to small pockets of electrons and holes, centered at the {ital X} points. The effective masses and extremal areas of the pockets are in good agreement with the predictions of band-structure calculations. We conclude that EuB{sub 6} is an intrinsic semimetal and not a doped insulator. The intrinsic carrier concentration is 1.2{times}10{sup 20} cm{sup {minus}3}, although our sample is somewhat uncompensated, with a 65{percent} surplus of holes. There is no appreciable modification to the Fermi-surface dimensions or carrier masses with the onset of ferromagnetism. {copyright} {ital 1999} {ital The American Physical Society}

  20. Space Environmental Effects Knowledgebase

    NASA Technical Reports Server (NTRS)

    Wood, B. E.

    2007-01-01

    This report describes the results of an NRA funded program entitled Space Environmental Effects Knowledgebase that received funding through a NASA NRA (NRA8-31) and was monitored by personnel in the NASA Space Environmental Effects (SEE) Program. The NASA Project number was 02029. The Satellite Contamination and Materials Outgassing Knowledgebase (SCMOK) was created as a part of the earlier NRA8-20. One of the previous tasks and part of the previously developed Knowledgebase was to accumulate data from facilities using QCMs to measure the outgassing data for satellite materials. The main object of this current program was to increase the number of material outgassing datasets from 250 up to approximately 500. As a part of this effort, a round-robin series of materials outgassing measurements program was also executed that allowed comparison of the results for the same materials tested in 10 different test facilities. Other programs tasks included obtaining datasets or information packages for 1) optical effects of contaminants on optical surfaces, thermal radiators, and sensor systems and 2) space environmental effects data and incorporating these data into the already existing NASA/SEE Knowledgebase.

  1. Using Your Library Effectively.

    ERIC Educational Resources Information Center

    Hennepin County Library, Minnetonka, MN.

    This collection of materials for a three-hour instructional program for young people and adults in the effective use of the public library includes an introduction to the program, a teaching guide for the librarian, a packet of materials for students, and a summary of 90 evaluations of the program as it was presented at two area libraries and…

  2. Teacher Effectiveness: A Position.

    ERIC Educational Resources Information Center

    Scott, Myrtle

    1969-01-01

    This document summarizes the highlights of research on teacher effectiveness and concludes with recommendations based on a synthesis of this past work. The various methodologies that have been used are discussed, from rating scales to objective observation techniques, such as OScAR and the ecological studies. The major problems in teacher…

  3. Effectively Communicating Qualitative Research

    ERIC Educational Resources Information Center

    Ponterotto, Joseph G.; Grieger, Ingrid

    2007-01-01

    This article is a guide for counseling researchers wishing to communicate the methods and results of their qualitative research to varied audiences. The authors posit that the first step in effectively communicating qualitative research is the development of strong qualitative research skills. To this end, the authors review a process model for…

  4. DCPS Effective Schools Framework

    ERIC Educational Resources Information Center

    District of Columbia Public Schools, 2009

    2009-01-01

    DCPS is committed to providing "all" students with the caliber of education they deserve. The goal of the DCPS Effective Schools Framework is to ensure that every child, in every classroom, has access to a high-quality and engaging standards-based instructional program, and that all school supports are aligned to support teaching and learning. The…

  5. Globalisation, Effectiveness and Improvement.

    ERIC Educational Resources Information Center

    Mortimore, Peter

    This paper reports principally on two studies, prompted by research on school effectiveness in the United States and England, which indicate globalization is beginning to affect school improvement. The first study cites case studies of two schools--from working-class, multi-ethnic, poorly educated areas of Singapore and London--to determine if…

  6. Effects of New Technologies.

    ERIC Educational Resources Information Center

    Social and Labour Bulletin, 1983

    1983-01-01

    A series of articles looks at computerization and unions in Australia, France, and India; bargaining agreements about technological innovation in India, the United Kingdom, and the United States; and the effects of technology on the labor force in the Federal Republic of Germany, Japan, and the United States. (SK)

  7. Marijuana: respiratory tract effects.

    PubMed

    Owen, Kelly P; Sutter, Mark E; Albertson, Timothy E

    2014-02-01

    Marijuana is the most commonly used drug of abuse in the USA. It is commonly abused through inhalation and therefore has effects on the lung that are similar to tobacco smoke, including increased cough, sputum production, hyperinflation, and upper lobe emphysematous changes. However, at this time, it does not appear that marijuana smoke contributes to the development of chronic obstructive pulmonary disease. Marijuana can have multiple physiologic effects such as tachycardia, peripheral vasodilatation, behavioral and emotional changes, and possible prolonged cognitive impairment. The carcinogenic effects of marijuana are unclear at this time. Studies are mixed on the ability of marijuana smoke to increase the risk for head and neck squamous cell carcinoma, lung cancer, prostate cancer, and cervical cancer. Some studies show that marijuana is protective for development of malignancy. Marijuana smoke has been shown to have an inhibitory effect on the immune system. Components of cannabis are under investigation as treatment for autoimmune diseases and malignancy. As marijuana becomes legalized in many states for medical and recreational use, other forms of tetrahydrocannabinol (THC) have been developed, such as food products and beverages. As most research on marijuana at this time has been on whole marijuana smoke, rather than THC, it is difficult to determine if the currently available data is applicable to these newer products. PMID:23715638

  8. Effective Thinking Outdoors.

    ERIC Educational Resources Information Center

    Hyde, Rod

    1997-01-01

    Effective Thinking Outdoors (ETO) is an organization that teaches thinking skills and strategies via significant outdoor experiences. Identifies the three elements of thinking as creativity, play, and persistence; presents a graphic depiction of the problem-solving process and aims; and describes an ETO exercise, determining old routes of travel…

  9. Effective Intervention for Bullying

    ERIC Educational Resources Information Center

    O'Neil, Randie; Kellner, Millicent H.; Green, Stuart; Elias, Maurice J.

    2012-01-01

    Most professional educators are aware that every school should have an effective approach to harassment, intimidation, and bullying (HIB) prevention in which every member of the school community participates. Regardless of the approach a school takes, all students and all staff members should be knowledgeable participants who have been trained to…

  10. The Effective Clinical Conference.

    ERIC Educational Resources Information Center

    Wink, Diane M.

    1995-01-01

    Examines the common problems with clinical conferences and suggests approaches to maximize student learning. Suggests that an effective clinical conference has three characteristics: (1) it is a group event; (2) it contributes to the achievement of course and clinical objectives; and (3) it provides a setting for students to explore personal…

  11. Designing "Educationally Effective" Discussion

    ERIC Educational Resources Information Center

    Swann, Joan

    2007-01-01

    This paper analyses data from a curriculum intervention project designed to introduce new forms of discussion, seen as educationally effective, into the primary classroom. While the introduction of talk as an aid to learning is premised on a social approach to learning, such interventions are often evaluated in terms of cognitive benefits and…

  12. Effects of nuclear war

    SciTech Connect

    von Hippel, F.

    1983-01-01

    The author reviews the subject rising the following topics and subtopics: I. Nuclear explosions: heat, nuclear radiation, and radioactive fallout; II. Effects: radiation sickness, burns, blast injuries, and equivalent areas of death; III. Nuclear war: battlefield, regional, intercontinental - counterforce, and intercontinental - counter-city and industry. There are two appendices. 34 references, 32 figures.

  13. Qualities of Effective Principals

    ERIC Educational Resources Information Center

    Stronge, James H.; Richard, Holly B.; Catano, Nancy

    2008-01-01

    You know how important principals are in advancing student achievement and school success, but it's not been exactly clear which components of the principal's job are the highest priority... until now. Following on the results-based approach from the ASCD best-seller "Qualities of Effective Teachers", James Stronge and his coauthors explain how…

  14. Effective Use of Usenet.

    ERIC Educational Resources Information Center

    Nickerson, Gord

    1992-01-01

    Continues a description of the Usenet computer network that began in the previous issue. The effective use of Usenet is discussed, including how to screen out unwanted information, the most helpful newsgroups to access, and setting up news reader software. Ideas for library outreach services via Usenet are also suggested. (LRW)

  15. Reporting Research Results Effectively

    ERIC Educational Resources Information Center

    Volkwein, J. Fredericks

    2010-01-01

    Assessment research is at its best when it packages research results and data so that they can be digested by multiple audiences. Too many assessment researchers spend all their efforts planning and executing the research project with little attention to closing the loop at the end. If assessment findings are not communicated effectively, the…

  16. Contaminant effects on fisheries

    SciTech Connect

    Cairns, V.W.; Hodson, P.V.; Nriagu, J.O.

    1984-01-01

    These proceedings collect papers on the effects of water pollution on fish and fisheries. Topics include: monitoring lead pollution in fish, metallothionein and acclimation to heavy metals in fish, modeling approaches, appraising the status of fisheries, and assessing the health of aquatic ecosystems.

  17. Effects on saltwater organisms

    SciTech Connect

    Reish, D.J.; Oshida, P.S.; Wilkes, F.G.; Mearns, A.J.; Ginn, T.C.; Carr, R.S.

    1984-06-01

    A review of the literature reveals numerous articles dealing with the uptake of metals by marine organisms. Cadmium, copper, zinc, and methyl mercury have been shown to have toxic effects on fish, oysters, clams, lobsters, and other marine animals. Both genetic and environmental factors are involved in the accumulation of these metals. 237 references.

  18. Is Effective Teaching Stable?

    ERIC Educational Resources Information Center

    Patrick, Helen; Mantzicopoulos, Panayota

    2016-01-01

    The authors examined the ecological validity of using observation-based scores to evaluate individual teachers' effectiveness, mirroring their use by school administrators. Using the Classroom Assessment Scoring System, the authors asked (a) how similar are teachers' emotional support, classroom organization, and instructional support scores from…

  19. Microcircuit radiation effects databank

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Radiation test data submitted by many testers is collated to serve as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. Total dose damage information and single event upset cross sections, i.e., the probability of a soft error (bit flip) or of a hard error (latchup) are presented.

  20. Teaching Effective Interviewing Techniques.

    ERIC Educational Resources Information Center

    Clemons, Frankie

    Through careful preparation and followup, students can insure successful job interviews. If they evaluate their own skills and expectations and assess employer characteristics before interviews, they can increase their credibility with interviewers and make more effective job decisions. If they anticipate irrelevant or illegal questions on such…

  1. Heterologous vaccine effects.

    PubMed

    Saadatian-Elahi, Mitra; Aaby, Peter; Shann, Frank; Netea, Mihai G; Levy, Ofer; Louis, Jacques; Picot, Valentina; Greenberg, Michael; Warren, William

    2016-07-25

    The heterologous or non-specific effects (NSEs) of vaccines, at times defined as "off-target effects" suggest that they can affect the immune response to organisms other than their pathogen-specific intended purpose. These NSEs have been the subject of clinical, immunological and epidemiological studies and are increasingly recognized as an important biological process by a growing group of immunologists and epidemiologists. Much remain to be learned about the extent and underlying mechanisms for these effects. The conference "Off-target effects of vaccination" held in Annecy-France (June 8-10 2015) intended to take a holistic approach drawing from the fields of immunology, systems biology, epidemiology, bioinformatics, public health and regulatory science to address fundamental questions of immunological mechanisms, as well as translational questions about vaccines NSEs. NSE observations were examined using case-studies on live attenuated vaccines and non-live vaccines followed by discussion of studies of possible biological mechanisms. Some possible pathways forward in the study of vaccines NSE were identified and discussed by the expert group. PMID:27312214

  2. Pleiotropic effects of incretins

    PubMed Central

    Gupta, Vishal

    2012-01-01

    Drugs that augment the incretin system [glucagon like peptide (GLP) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors] represent a novel class of anti-hyperglycemic agents that have shown to improve the health and survival of beta-cells (improvement in postprandial hyperglycemia) and suppress glucagon (improvement in fasting hyperglycemia). The incretins represent a large family of molecules referred to as the “glucagon superfamily of peptide hormones” of which more than 90% of the physiological effects of incretins are accomplished by GLP-17-37 and GLP17-36 amide and gastric insulinotropic peptide (GIP). GLP-1 mediates its effects via the GLP-1 receptor, which has a wide tissue distribution [pancreas, lung, heart, vascular smooth muscle cells, endothelial cells, macrophages and monocytes, kidney, gastrointestinal tract (stomach and intestine), central nervous system (neoortex, cerebellum, hypothalamus, hippocampus, brainstem nucleus tractus solitarius) and peripheral nervous system]. This would imply that the incretin system has effects outside the pancreas. Over time data has accumulated to suggest that therapies that augment the incretin system has beneficial pleiotrophic effects. The incretins have shown to possess a cardiac-friendly profile, preserve neuronal cells and safeguard from neuronal degeneration, improve hepatic inflammation and hepatosteatosis, improve insulin resistance, promote weight loss and induce satiety. There is growing evidence that they may also be renoprotective promoting wound healing and bone health. PMID:22701844

  3. Building Effective Afterschool Programs.

    ERIC Educational Resources Information Center

    Fashola, Olatokunbo S.

    Through a comprehensive review of various afterschool programs across the United States, this resource provides a practical overview of the research and best practices that can be easily adapted and applied in the development of highly effective afterschool programs. chapters focus on: (1) "Why Afterschool Programs?" (benefits, challenges, and…

  4. The Negative Repetition Effect

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  5. Effective Nonverbal Communication.

    ERIC Educational Resources Information Center

    Parratt, Smitty

    1995-01-01

    Discusses the importance of understanding nonverbal communication in enhancing the personal and work relationships of interpreters and increasing their effectiveness in meeting the needs of customers. Discusses the mystique of body language, cultural variation in the use of gestures, the stages of an encounter, interpreting gesture clusters, and…

  6. Case 26: Somogyi effect

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This individual has a classic manifestation of the Somogyi effect, which is fasting morning hyperglycemia in response to hypoglycemia in the early morning and late night hours. The danger is that if night-time blood glucose levels are not measured, the physician may interpret the patient as having h...

  7. Alexandrite effect spectropyrometer

    NASA Astrophysics Data System (ADS)

    Liu, Yan

    2006-08-01

    Alexandrite crystal is commonly used for making alexandrite laser, and it also has a less-known phenomenon called the alexandrite effect that refers to the color change between different light sources. A novel spectropyrometer for temperature measurement of a radiating body utilizing the alexandrite effect is introduced. The alexandrite effect method for temperature measurement is based on the relationship between the temperature of blackbody and the hue-angle in the CIELAB color space. The alexandrite effect spectropyrometer consists of an optical probe, a spectrometer, a computer, and an alexandrite filter. It measures the spectral power distribution of a radiating body through the alexandrite filter, calculates the hue-angle, and determines the temperature. The spectropyrometer is suitable for temperature measurement of any radiating body with or without spectral lines in its spectral power distribution from 1000 K to 100000 K. The spectropyrometer is particularly useful for high to ultrahigh temperature measurement of any radiating bodies with spectral line emissions, such as electric arcs and discharges, plasmas, and high temperature flames.

  8. Tips for Effective Management

    ERIC Educational Resources Information Center

    Supple, Kevin F.

    2009-01-01

    School business officials' days are filled with numbers and reports--audits, balance sheets, check registers, financial statements, journal entries, vouchers, and warrant reports, just to name a few. Those are all important tools that school business officers use to manage the financial resources of the district effectively. However, they are also…

  9. Cost Effective Prototyping

    NASA Technical Reports Server (NTRS)

    Wickman, Jerry L.; Kundu, Nikhil K.

    1996-01-01

    This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

  10. Radiation: Doses, Effects, Risks.

    ERIC Educational Resources Information Center

    Lean, Geoffrey, Ed.

    Few scientific issues arouse as much public controversy as the effects of radiation. This booklet is an attempt to summarize what is known about radiation and provide a basis for further discussion and debate. The first four chapters of the booklet are based on the most recent reports to the United Nations' General Assembly by the United Nations…

  11. Fast and effective?

    PubMed

    Trueland, Jennifer

    2013-12-18

    The 5.2 diet involves two days of fasting each week. It is being promoted as the key to sustained weight loss, as well as wider health benefits, despite the lack of evidence on the long-term effects. Nurses need to support patients who wish to try intermittent fasting. PMID:24345130

  12. The Effective, Efficient Professor.

    ERIC Educational Resources Information Center

    Felder, Richard M.

    2002-01-01

    Presents a succinct overview of the book "The Effective, Efficient Professor" (P. Wankat) that presents a wealth of strategies and techniques for successful faculty members. Sections of the book focus on time management, teaching, students, and scholarship and service. Includes some practical tips from the book ranging from instructional…

  13. Desert Storm environmental effects

    NASA Astrophysics Data System (ADS)

    Kimball, E. W.

    It is noted that after more than six months of operation of the Patriot launch station in the Saudi Arabian desert no problems that were attributed to high temperature occurred. The environmental anomalies that did occur were cosmetic in nature and related to dust and salt fog. It was concluded that the Desert Storm environmental effects were typical of worldwide hot, dry climates.

  14. Effects of Induced Astigmatism.

    ERIC Educational Resources Information Center

    Schubert, Delwyn G.; Walton, Howard N.

    1968-01-01

    The relationship of astigmatism to reading and the possible detrimental effects it might have on reading were investigated. The greatest incidence of astigmatism was for the with-the-rule type ranging from .50 to 1.00 diopter. This type of astigmatism was induced in 35 seniors from the Los Angeles College of Optometry by placing cylindrical lenses…

  15. Making Effective Assignments.

    ERIC Educational Resources Information Center

    McLeod, Alan M., Ed.

    1982-01-01

    Although the focus of this issue of the "Virginia English Bulletin" is on making effective assignments, most of the articles also emphasize the importance and power of writing. Articles deal with the following topics: (1) the use of I-search (as explained by Kenneth Macrorie in "Searching Writing") as a form of research paper that narrates the…

  16. Using Media Effectively.

    ERIC Educational Resources Information Center

    Danzer, Gerald A.; Newman, Mark

    1992-01-01

    Recommends that media presentations can be used effectively in the history classroom as images of reality. Suggests films and television programs and documentaries that can be utilized to show how movies play a role in shaping opinion and changing perceptions. (DK)

  17. Conducting Effective Simulator Training.

    ERIC Educational Resources Information Center

    Gerling, Kenneth D.

    This paper describes the simulator phase of Commonwealth Edison's program for training and licensing operators of nuclear power stations. Topics covered include (1) preparing the students before starting the simulator phase; (2) the simulator schedule and the number of students that can be trained effectively in a class; (3) format and structure…

  18. Research and Teacher Effectiveness.

    ERIC Educational Resources Information Center

    Berliner, David

    This paper presents one researcher's premise that the most important variable in determining classroom effectiveness is the congruence of the delivered curriculum with the desired outcomes or, that students be given the opportunity to learn what is expected of them. This theory presupposes that curriculum expectations be made clear to students,…

  19. Measuring Teacher Effectiveness

    ERIC Educational Resources Information Center

    Jacobo, Amber Leann

    2012-01-01

    Prior research has shown that there is a correlation between teacher characteristics (e.g., pedagogical knowledge, teacher preparation/certification) and student achievement. Current political contexts call for the utilization of student achievement data to measure the effectiveness of our education systems. A solid research base of how teacher…

  20. BIOLOGICAL EFFECTS OF MANGANESE

    EPA Science Inventory

    The biological effects of manganese were studied in a town on the coast of Dalmatia in which a ferromanganese plant has been operating since before World War II. The study focused on the question of whether the exposure to manganese can cause a higher incidence of respiratory dis...

  1. Creating Effective Multimedia Instruction.

    ERIC Educational Resources Information Center

    Sales, Gregory C.

    1999-01-01

    Presents information on several critical themes related to multimedia instruction for those involved in the design, development, or use of computer delivered instruction. Addresses software product life cycle; systematic approach to design; multimedia design and development teams; production values; critical components of effective multimedia;…

  2. Dimensions of Effective Leadership.

    ERIC Educational Resources Information Center

    Duttweiler, Patricia Cloud; Hord, Shirley M.

    This volume provides a comprehensive synthesis of competencies that research has associated with the administration of effective schools. Following an introduction, section 1, "Re-thinking the Organizational Structure of Schools," presents current thinking on the organizational structure in which school administrators function. Alternative models…

  3. Educator Effectiveness Administrative Manual

    ERIC Educational Resources Information Center

    Pennsylvania Department of Education, 2014

    2014-01-01

    The goal of this manual is to provide guidance in the evaluation of educators, highlight critical components of effectiveness training, and offer opportunities for professional growth. The term "educator" includes teachers, all professional and temporary professional employees, education specialists, and school administrators/principals.…

  4. Evaluating Effective Supervision.

    ERIC Educational Resources Information Center

    Worthen, Vaughn E.; Dougher, M. Kirk

    This paper outlines the purposes, professional obligations, and key components to consider when providing effective evaluation in psychotherapy supervision. An overview of various methods for gathering supervision data for evaluation purposes is provided including self-reporting; process notes; video and audiotaping; live observation; co-therapy;…

  5. Holding Effective Board Meetings.

    ERIC Educational Resources Information Center

    American Association of School Administrators, Arlington, VA.

    Advice and tested methods for management of meetings from superintendents and board members are combined in this reference book on conducting effective school board meetings. Intended for a wide readership, it contains three chapters and an exhibit section comprising over one-third of the document. Following a brief introduction, chapter 1,…

  6. Effective Classroom Management

    ERIC Educational Resources Information Center

    Mansor, Azlin Norhaini; Eng, Wong Kim; Rasul, Mohamad Sattar; Hamzah, Mohd Izham Mohd; Hamid, Aida Hanim A.

    2012-01-01

    This paper attempts to explore and identify the characteristics of an effective teacher who teaches English as a second language to 10 year old students from different ethnics, various social economic background and multi-level language ability, at a private primary school in Malaysia. The study focused on classroom management using a case study…

  7. Resources for Effective Teaching.

    ERIC Educational Resources Information Center

    Walline, Jane K.

    A special studies institute on resources for effective teaching was designed to train newly appointed or potential Curriculum Resource Consultants (CRC) who work in conjunction with special education instructional materials centers in Michigan. Objectives of the workshop sequences included the development of teacher-training competencies in the…

  8. Commentary: Expanding on Effectiveness

    ERIC Educational Resources Information Center

    Pelham, William E., Jr.; Massetti, Greta M.

    2003-01-01

    Atkins, Graczyk, Frazier, and Abdul-Adil (2003) make the point that there have been three limitations of mental health services for children and families in low-income, urban settings: (a) accessibility; (b) effectiveness; and (c) sustainability. Their article focuses extensively on improving access and addressing issues of sustainability in…

  9. Cardiovascular effects of alcohol.

    PubMed Central

    Davidson, D M

    1989-01-01

    The effects of alcohol on the heart include modification of the risk of coronary artery disease, the development of alcoholic cardiomyopathy, exacerbation of conduction disorders, atrial and ventricular dysrhythmias, and an increased risk of hypertension, hemorrhagic stroke, infectious endocarditis, and fetal heart abnormalities. PMID:2686174

  10. Effective Staff Development.

    ERIC Educational Resources Information Center

    Bush, Robert N.

    Beginning with the observation that educators are faced with rising public expectations, declining resources, and increased public criticism, this paper describes a six-fold model for determining how staff development is operating and how it can be made to operate more effectively, in a self-renewing manner. The six dimensions consist of the…

  11. Minnesota School Effectiveness Program.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Education, St. Paul.

    This packet is designed to assist educational leaders in presenting current research-based information on the characteristics of effective schools to their school staff. The packet is divided into five sections, each including a sample presentation script, transparency models, and worksheets for promoting group discussion. The first section is an…

  12. Matthew Effects for Whom?

    ERIC Educational Resources Information Center

    Morgan, Paul L.; Farkas, George; Hibel, Jacob

    2008-01-01

    Which children are most at risk of experiencing a Matthew effect in reading? We investigated this question using population-based methodology. First, we identified children entering kindergarten on socio-demographic factors (i.e., gender, race/ethnicity, and socioeconomic status) known to index the relative risks and resources available to them as…

  13. Effective Monitor Display Design.

    ERIC Educational Resources Information Center

    Harrell, William

    1999-01-01

    Describes some of the factors that affect computer monitor display design and provides suggestions and insights into how screen displays can be designed more effectively. Topics include color, font choices, organizational structure of text, space outline, and general principles. (Author/LRW)

  14. Brain effects of melanocortins.

    PubMed

    Bertolini, Alfio; Tacchi, Raffaella; Vergoni, Anna Valeria

    2009-01-01

    The melanocortins (alpha, beta and gamma-melanocyte-stimulating hormones: MSHs; adrenocorticotrophic hormone: ACTH), a family of pro-opiomelanocortin (POMC)-derived peptides having in common the tetrapeptide sequence His-Phe-Arg-Trp, have progressively revealed an incredibly wide range of extra-hormonal effects, so to become one of the most promising source of innovative drugs for many, important and widespread pathological conditions. The discovery of their effects on some brain functions, independently made by William Ferrari and David De Wied about half a century ago, led to the formulation of the term "neuropeptide" at a time when no demonstration of the actual production of peptide molecules by neurons, in the brain, was still available, and there were no receptors characterized for these molecules. In the course of the subsequent decades it came out that melanocortins, besides inducing one of the most complex and bizarre behavioural syndromes (excessive grooming, crises of stretchings and yawnings, repeated episodes of spontaneous penile erection and ejaculation, increased sexual receptivity), play a key role in functions of fundamental physiological importance as well as impressive therapeutic effects in different pathological conditions. If serendipity had been an important determinant in the discovery of the above-mentioned first-noticed extra-hormonal effects of melanocortins, many of the subsequent discoveries in the pharmacology of these peptides (feeding inhibition, shock reversal, role in opiate tolerance/withdrawal, etc.) have been the result of a planned research, aimed at testing the "pro-nociceptive/anti-nociceptive homeostatic system" hypothesis. The discovery of melanocortin receptors, and the ensuing synthesis of selective ligands with agonist or antagonist activity, is generating completely innovative drugs for the treatment of a potentially very long list of important and widespread pathological conditions: sexual impotence, frigidity

  15. Stormwater BMP Effectiveness Assessment Toolkit

    EPA Science Inventory

    US EPA has identified stormwater BMP effectiveness as a priority research need. Effective protection of biotic integrity requires that processes maintaining the diversity of physical habitats be protected. Methods are needed to evaluate the effectiveness of existing Stormwater ...

  16. Health Effects of Air Pollution

    MedlinePlus

    ... Health effects of air pollution Health effects of air pollution Breathing air that is not clean can hurt ... important to know about the health effects that air pollution can have on you and others. Once you ...

  17. Effects of Medications on Voice

    MedlinePlus

    ... Meeting Calendar Find an ENT Doctor Near You Effects of Medications on Voice Effects of Medications on Voice Patient Health Information News ... replacement therapy post-menopause may have a variable effect. An inadequate level of thyroid replacement medication in ...

  18. Administrative Effectiveness in Higher Education.

    ERIC Educational Resources Information Center

    Whetten, David A.; Cameron, Kim S.

    1985-01-01

    Determinants of organizational and administrative effectiveness in higher education are discussed, and eight administrator characteristics associated with maintaining and enhancing institutional effectiveness are identified. (MSE)

  19. Leptophilic effective WIMPs

    NASA Astrophysics Data System (ADS)

    Chang, Spencer; Edezhath, Ralph; Hutchinson, Jeffrey; Luty, Markus

    2014-07-01

    Effective weakly interacting massive particle (WIMP) models are minimal extensions of the standard model that explain the relic density of dark matter by the "WIMP miracle." In this paper we consider the phenomenology of effective WIMPs with trilinear couplings to leptons and a new "lepton partner" particle. The observed relic abundance fixes the strength of the cubic coupling, so the parameters of the models are defined by the masses of the WIMP and lepton partner particles. This gives a simple parameter space where collider and direct detection experiments can be compared under well-defined physical minimality assumptions. The most sensitive collider probe is the search for leptons+MET, while the most sensitive direct detection channel is scattering from nuclei arising from loop diagrams. Collider and direct detection searches are highly complementary: colliders give the only meaningful constraint when dark matter is its own antiparticle, while direct detection is generally more sensitive if the dark matter is not its own antiparticle.

  20. Developmental effects of dioxins.

    PubMed Central

    Birnbaum, L S

    1995-01-01

    The potent developmental toxicity of dioxin in multiple species has been known for a number of years. However, recent studies have indicated that dioxin also induces functional developmental defects, many of which are delayed. Subtle structural deficits, not detectable at birth, have also been described in multiple species and in both sexes. Certain defects have been reported not only in animals but also in children prenatally exposed to complex mixtures containing dioxinlike compounds. None of the effects can be attributed to modulation of any one endocrine system. For example, dioxin does not bind to the estrogen receptor, but it can cause effects that are both estrogenic and antiestrogenic. However, viewing dioxin and related compounds as endocrine disruptors that may alter multiple pathways sheds some light on the complexities of this potent class of growth dysregulators. PMID:8593882

  1. Fuel Vaporization Effects

    NASA Technical Reports Server (NTRS)

    Bosque, M. A.

    1983-01-01

    A study of the effects of fuel-air preparation characteristics on combustor performance and emissions at temperature and pressure ranges representative of actual gas turbine combustors is discussed. The effect of flameholding devices on the vaporization process and NOx formation is discussed. Flameholder blockage and geometry are some of the elements that affect the recirculation zone characteristics and subsequently alter combustion stability, emissions and performance. A water cooled combustor is used as the test rig. Preheated air and Jet A fuel are mixed at the entrance of the apparatus. A vaporization probe is used to determine percentage of vaporization and a gas sample probe to determine concentration of emissions in the exhaust gases. The experimental design is presented and experimental expected results are discussed.

  2. Latent effects decision analysis

    DOEpatents

    Cooper, J. Arlin; Werner, Paul W.

    2004-08-24

    Latent effects on a system are broken down into components ranging from those far removed in time from the system under study (latent) to those which closely effect changes in the system. Each component is provided with weighted inputs either by a user or from outputs of other components. A non-linear mathematical process known as `soft aggregation` is performed on the inputs to each component to provide information relating to the component. This information is combined in decreasing order of latency to the system to provide a quantifiable measure of an attribute of a system (e.g., safety) or to test hypotheses (e.g., for forensic deduction or decisions about various system design options).

  3. Establishing effective working relationships.

    PubMed

    Houghton, Trish

    2016-02-24

    This article, the second in a series of 11, provides support and offers advice to new and existing mentors and practice teachers to enable them to progress in their role and develop a portfolio of evidence. In particular, the article discusses how to establish effective working relationships and emphasises the importance of the student-mentor or student-practice teacher relationship. It examines the essential qualities, attributes and characteristics of an effective mentor or practice teacher. The article provides learning activities and suggests ways in which mentors and practice teachers can undertake various self-assessments, enabling them to gather relevant evidence to demonstrate how they can meet and maintain the requirements for these roles as stipulated by the Nursing and Midwifery Council. PMID:26907148

  4. Are diabetes camps effective?

    PubMed

    Barone, Mark Thomaz Ugliara; Vivolo, Marco Antonio; Madden, Paul B

    2016-04-01

    In the present article data about Diabetes Camps (DC) from all continents were reviewed in order to answer the title question "are diabetes camps effective?". Articles from peer reviewed journals and abstracts published in international conferences proceedings were raised. The effectiveness was considered in terms of knowledge acquisition, and psychosocial and physiological changes. Even though expected improvements were not found in all studies, in a deeper and wider analysis the aspects that influence the most toward gains are identified. Among them are: number of participations in a DC, post-camp educational opportunities, staff training, and program oriented toward campers' autonomy. To conclude, practical recommendations are addressed intending to amplify DC's potential. PMID:27103364

  5. Cerebroprotective effect of flunarizine.

    PubMed

    Nikolov, R; Nikolova, M; Dikova, M; Mirzoyan, R S; Ganshina, T S; Volobueva, T I

    1990-01-01

    The cerebroprotective effect of flunarizine was studied using the following methods: hypobaric hypoxia in mice, complete ischemia by decapitation in mice, anoxic hypoxia in mice, hemic hypoxia in rats, incomplete ischemia by bilateral carotid ligation in rats and asphyxic hypoxia in cats. Piracetam, meclofenoxate, nicergoline, naftidrofuryl, cinnarizine and nifedipine were studied as reference drugs. Flunarizine increased the survival time in all survival models. Its effect was most pronounced in complete ischemia model, and considerably higher than that of reference drugs. In asphyxic hypoxia flunarizine increased cortical resistance and shortened cortical recovery. The EEG frequency-amplitude analysis during asphyxic hypoxia showed a significant decrease of the slow-waves amplitudes of delta and theta range, and an increase of the fast-waves amplitudes of beta-2 range, changes indicating protective action. PMID:2087140

  6. Effectively managing wound exudate.

    PubMed

    Chamanga, Edwin

    2015-09-01

    The management of wound exudate remains a clinical challenge despite technological advances in products with better exudate-handling capacities. This clinical challenge is occasionally encountered when thick exudate (viscous exudate) is present, and when most modern dressings do not possess the capabilities to manage the viscosity while enabling exudate absorption. Maceration to the peri-wound area poses another challenge, irrespective of the number of topical barrier application products on the market and the innovation of dressing products that lock exudate away or those that encourage vertical wicking. In addition to all the above, in clinical practice, the assessment and documentation of wound exudate remains sporadic, leading to the challenges of effective wound exudate dressing selection and cost-effective dressings. PMID:26322408

  7. Safety Intervention Effectiveness

    SciTech Connect

    ZIMMERMAN, R.O.

    2001-10-16

    Judging safety intervention effectiveness is often left up to the eye of the beholder. Safety and Health Professionals must increase skills and increase their body of knowledge, based on scientific evidence, that can be applied confidently in the workplace. Evidence must be collected and analyzed to separate the interventions of the month with those that stand the test of time. The book Guide to Evaluating the Effectiveness of Strategies for Preventing Work injuries DHHS (NIOSH) Publication No. 2001-119, April 2001, serves as a primary reference. An example study related to biorhythms, popular in the late 1970s, is used to illustrate the separating of scientific evidence and pseudo-science hype. The cited biorhythm study focuses on the relationship of the accident dates and the three biorhythmic cycles (physical, emotional, and intelligence).

  8. Relativistic Hall effect.

    PubMed

    Bliokh, Konstantin Y; Nori, Franco

    2012-03-23

    We consider the relativistic deformation of quantum waves and mechanical bodies carrying intrinsic angular momentum (AM). When observed in a moving reference frame, the centroid of the object undergoes an AM-dependent transverse shift. This is the relativistic analogue of the spin-Hall effect, which occurs in free space without any external fields. Remarkably, the shifts of the geometric and energy centroids differ by a factor of 2, and both centroids are crucial for the Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices and mechanical flywheels and also discuss various fundamental aspects of this phenomenon. The perfect agreement of quantum and relativistic approaches allows applications at strikingly different scales, from elementary spinning particles, through classical light, to rotating black holes. PMID:22540559

  9. Lightning effects on aircraft

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Direct and indirect effects of lightning on aircraft were examined in relation to aircraft design. Specific trends in design leading to more frequent lightning strikes were individually investigated. These trends included the increasing use of miniaturized, solid state components in aircraft electronics and electric power systems. A second trend studied was the increasing use of reinforced plastics and other nonconducting materials in place of aluminum skins, a practice that reduces the electromagnetic shielding furnished by a conductive skin.

  10. Botany: floral fluorescence effect.

    PubMed

    Gandía-Herrero, Fernando; García-Carmona, Francisco; Escribano, Josefa

    2005-09-15

    The way flowers appear to insects is crucial for pollination. Here we describe an internal light-filtering effect in the flowers of Mirabilis jalapa, in which the visible fluorescence emitted by one pigment, a yellow betaxanthin, is absorbed by another, a violet betacyanin, to create a contrasting fluorescent pattern on the flower's petals. This finding opens up new possibilities for pollinator perception as fluorescence has not previously been considered as a potential signal in flowers. PMID:16163341

  11. The Kaye effect

    NASA Astrophysics Data System (ADS)

    Binder, J. M.; Landig, A. J.

    2009-11-01

    The International Young Physicists' Tournament (IYPT) is a worldwide, annual competition for secondary school students. This is our solution to problem number 10, The Kaye effect, as presented in the final round of the 21st IYPT in Trogir, Croatia. The Kaye effect occurs when a thin stream of shampoo or a different adequate non-Newtonian liquid is poured onto a surface. Suddenly, a jet leaves the heap that is formed by the shampoo and begins to 'dance' around the primary jet like a lasso. The phenomenon ends when the 'dancing' jet hits the primary jet and subsequently collapses. We started our investigations based on available literature (Kaye 1963 Nature 197 1001, Versluis et al 2006 J. Stat. Mech., Collyer and Fischer 1976 Nature 261 682). We made experiments with a similar experimental set-up in which we could determine the velocities of both shampoo streams as well as the angle of the 'dancing' stream. From there on, we developed a theoretical model for the energy loss of the jet in the heap. We discovered that the air layer between the jet and the heap is a necessity for the Kaye effect to occur. At this point, our observations differ from the aforementioned literature. This also accounts for the shampoo beam acting as a light guide. Further experiments concerning the viscoelasticity of the shampoo revealed that the elastic property of the shampoo is necessary for the effect to occur. This article is a written version of the oral contribution of the German team to the 21st IYPT competition, which was awarded first prize by an international jury. The article has been edited by European Journal of Physics.

  12. Nonlocal anomalous Hall effect

    NASA Astrophysics Data System (ADS)

    Zhang, Shulei; Vignale, Giovanni

    Anomalous Hall effect (AHE) is a distinctive transport property of ferromagnetic metals arising from spin orbit coupling (SOC) in concert with spontaneous spin polarization. Nonetheless, recent experiments have shown that the effect also appears in a nonmagnetic metal in contact with a magnetic insulator. The main puzzle lies in the apparent absence of spin polarized electrons in the non-magnetic metal. Here, we theoretically demonstrate that the scattering of electrons from a rough metal-insulator interface is generally spin-dependent, which results in mutual conversion between spin and charge currents flowing in the plane of the layer. It is the current-carrying spin polarized electrons and the spin Hall effect in the bulk of the metal layer that conspire to generate the AH current. This novel AHE differs from the conventional one only in the spatial separation of the SOC and the magnetization, so we name it as nonlocal AHE. In contrast to other previously proposed mechanisms (e.g., spin Hall AHE and magnetic proximity effect (MPE)), the nonlocal AHE appears on the first order of spin Hall angle and does not rely on the induced moments in the metal layer, which make it experimentally detectable by contrasting the AH current directions of two layered structures such as Pt/Cu/YIG and β -Ta/Cu/YIG (with a thin inserted Cu layer to eliminate the MPE). We predict that the directions of the AH currents in these two trilayers would be opposite since the spin Hall angles of Pt and β -Ta are of opposite signs. Work supported by NSF Grants DMR-1406568.

  13. Vascular Effects of Histamine.

    PubMed

    Ebeigbe, Anthony B; Talabi, Olufunke O

    2014-01-01

    Four subtypes of receptors (H1, H2, H3 and H4) mediate the actions of histamine. In the vascular wall, the effects of histamine are mediated via H1 and H2 receptors and the actions are modulated by H3 receptor subtype located on presynaptic neurones. Alterations in vascular responses to histamine are associated with experimental as well as a human form of hypertension, suggesting a role for histanine in cardiovascular regulation. PMID:26196559

  14. Neuroprotective effects of Asiaticoside

    PubMed Central

    Qi, Feng-yan; Yang, Le; Tian, Zhen; Zhao, Ming-gao; Liu, Shui-bing; An, Jia-ze

    2014-01-01

    In the central nervous system, Asiaticoside has been shown to attenuate in vitro neuronal damage caused by exposure to β-amyloid. In vivo studies demonstrated that Asiaticoside could attenuate neurobehavioral, neurochemical and histological changes in transient focal middle cerebral artery occlusion animals. In addition, Asiaticoside showed anxiolytic effects in acute and chronic stress animals. However, its potential neuroprotective properties in glutamate-induced excitotoxicity have not been fully studied. We investigated the neuroprotective effects of Asiaticoside in primary cultured mouse cortical neurons exposed to glutamate-induced excitotoxicity invoked by N-methyl-D-aspartate. Pretreatment with Asiaticoside decreased neuronal cell loss in a concentration-dependent manner and restored changes in expression of apoptotic-related proteins Bcl-2 and Bax. Asiaticoside pretreatment also attenuated the upregulation of NR2B expression, a subunit of N-methyl-D-aspartate receptors, but did not affect expression of NR2A subunits. Additionally, in cultured neurons, Asiaticoside significantly inhibited Ca2+ influx induced by N-methyl-D-aspartate. These experimental findings provide preliminary evidence that during excitotoxicity induced by N-methyl-D-aspartate exposure in cultured cortical neurons, the neuroprotective effects of Asiaticoside are mediated through inhibition of calcium influx. Aside from its anti-oxidant activity, down-regulation of NR2B-containing N-methyl-D-aspartate receptors may be one of the underlying mechanisms in Asiaticoside neuroprotection. PMID:25221579

  15. Generalized Effective Radiance Temperature

    NASA Astrophysics Data System (ADS)

    Yuan, Z.

    2015-12-01

    Radiance temperature is one of the most important and widely used concepts in radiation thermometry. The usual definition of radiance temperature does not strictly apply for complex situations, such as when surrounding radiation is non-negligible or when corrections are applied to measurements made using an inappropriate emissivity setting. A novel concept, generalized effective radiance temperature (GERT), that adopts a graybody as the reference radiator is proposed in this study to express and explain the actual measurands that exist extensively in practical radiation thermometry applications; for example, a measurement result by a spectral-band radiation thermometer whose instrumental emissivity setting is less than 1. An effective wavelength approach has been developed to elucidate the relationship between a thermometer-dependent temperature (reading from an actual spectral-band radiation thermometer) and the object-side parameter GERT. The characteristics of GERT and the effective wavelength of a GERT measurement are discussed. Choosing an arbitrary emissivity setting to correct for the emissivity of a real target is equivalent to using this value as the emissivity of the reference graybody of the GERT. The GERT can be used in calibrations of both sources and thermometers.

  16. Pleiotropic effects of statins.

    PubMed

    Farmer, J A

    2000-05-01

    The advent of statin therapy has revolutionized the ability of the clinician to manage patients at risk for the development of an ischemic event due to dyslipidemia. Large-scale clinical trials involving thousands of patients in both primary and secondary prevention have clearly demonstrated that statin therapy will reduce cardiovascular mortality across a broad spectrum of patient subgroups. Additionally, in adequately powered trials, total mortality has been successfully decreased by the use of statin therapy. However, the precise mechanism underlying the benefit of statin therapy has been controversial due to the multiplicity of potential benefits that statins have demonstrated in addition to pure lipid lowering. The causal theory of pharmacologic benefit reiterates the lipid hypothesis, which states that dyslipidemia is central to the process of atherosclerosis and the clinical benefit which accrues from statin therapy is a function of the degree of lipid lowering. The noncausal theory supports the premise that clinical benefits are related primarily to pleiotropic effects of statins (endothelial function, inflammation, coagulation and plaque vulnerability) as being the major modulators of clinical benefit. This review will focus on the potential beneficial effects of statin therapy on a number of the pleiotropic effects of statins and the potential role that these activities play in the reduction of risk for ischemic events. PMID:11122746

  17. Effectiveness of smokeless ashtrays.

    PubMed

    Wampler, D A; Miller-Leiden, S; Nazaroff, W W; Gadgil, A J; Litvak, A; Mahanama, K R; Nematollahi, M

    1995-06-01

    Most environmental tobacco smoke (ETS) issues from the tips of smoldering cigarettes between puffs. Smokeless ashtrays are designed to reduce ETS exposure by removing particulate and/or gas-phase contaminants from this plume. This paper describes an experimental investigation of the effectiveness of four smokeless ashtrays: two commercial devices and two prototypes constructed by the authors. In the basic experimental protocol, one or more cigarettes was permitted to smolder in a room. Particulate or gas-phase pollutant concentrations were measured in the room air over time. Device effectiveness was determined by comparing pollutant concentrations with the device in use to those obtained with no control device. A lung deposition model was applied to further interpret device effectiveness for particle removal. The commercial ashtrays were found to be substantially ineffective in removing ETS particles because of the use of low-quality filter media and/or the failure to draw the smoke through the filter. A prototype ashtray using HEPA filter material achieved better than 90% particle removal efficiency. Gas-phase pollutant removal was tested for only one prototype smokeless ashtray, which employed filters containing activated carbon and activated alumina. Removal efficiencies for the 18 gas-phase compounds measured (above the detection limit) were in the range of 70 to 95%. PMID:7788509

  18. Cascading Effects Following Intervention

    PubMed Central

    Patterson, Gerald R.; Forgatch, Marion S.; DeGarmo, David S.

    2010-01-01

    Four different sources for cascade effects were examined using 9-year process and outcome data from a randomized controlled trial (RCT) of a preventive intervention using Parent Management Training – Oregon Model (PMTO™). The social interaction learning (SIL) model of child antisocial behavior serves as one basis for predicting change. A second source addresses the issue of comorbid relationships among clinical diagnoses. The third source, collateral changes, describes events in which changes in one family member correlate with changes in another. The fourth component is based on the long-term effects of reducing coercion and increasing positive interpersonal processes within the family. New findings from the 9-year follow-up show that mothers experienced benefits as measured by standard of living (i.e., income, occupation, education, and financial stress) and frequency of police arrests. It is assumed that PMTO reduces the level of coercion, which sets the stage for a massive increase in positive social interaction. In effect, PMTO alters the family environment and thereby opens doors to healthy new social environments. PMID:20883592

  19. SOLAR EFFECTS ON BUILDING DESIGN.

    ERIC Educational Resources Information Center

    Building Research Inst., Inc., Washington, DC.

    A REPORT OF A PROGRAM HELD AS PART OF THE BUILDING RESEARCH INSTITUTE 1962 SPRING CONFERENCE ON THE SOLAR EFFECTS ON BUILDING DESIGN. TOPICS DISCUSSED ARE--(1) SOLAR ENERGY DATA APPLICABLE TO BUILDING DESIGN, (2) THERMAL EFFECTS OF SOLAR RADIATION ON MAN, (3) SOLAR EFFECTS ON ARCHITECTURE, (4) SOLAR EFFECTS ON BUILDING COSTS, (5) SELECTION OF…

  20. Effects of dividing attention on the memory-block effect.

    PubMed

    Kinoshita, S; Towgood, K

    2001-05-01

    S. M. Smith and D. R. Tindell (1997) reported that prior study of words that are orthographically similar to the solutions of test word fragments (e.g., studying ANALOGY and completing the fragment A_L _ _GY, whose solution is ALLERGY) reduced the fragment completion rate relative to a baseline condition in which unrelated words were studied. They called this effect the memory-block effect. In the present experiment, the authors replicated this effect using a larger set of materials than that used by S. M. Smith and D. R. Tindell. The authors also found that dividing attention at study eliminated the memory-block effect. This pattern mimicked the effect of dividing attention on recognition memory but differed from the effect on repetition priming effects. The authors suggest that the memory-block effect is driven by a mechanism different from that responsible for producing repetition priming effects in an implicit fragment completion test. PMID:11394687

  1. 'The Kesterson effect'

    USGS Publications Warehouse

    Presser, T.S.

    1994-01-01

    Hypothesized to be derived from Cretaceous marine sedimentary rocks, selenium contamination of the Kesterson National Wildlife Refuge is traced through irrigation drainage to the source bedrock of the California Coast Ranges. This biogeochemical pathway of selenium is defined here as the 'Kesterson effect.' At the refuge ponds, this effect culminated in 1983 in a 64% rate of deformity and death of embryos and hatchlings of wild aquatic birds. From the previous companion paper on irrigation drainage, the Kesterson effect has been implicated in nine of 11 reconnaissance areas studied in the western United States. Deformities have resulted in at least five of these sites. Climatic, geologic, hydrologic, and soil conditions in these reconnaissance areas are similar to those in the area surrounding Kesterson National Wildlife Refuge in the west-central San Joaquin Valley of California, in California, selenium as selenate, was ultimately found weathered with sulfur from marine sources in soluble sodium and magnesium sulfate salts, which are concentrated by evaporation on farmland soils. The Se, mobilized by irrigation drainage, is bioaccumulated to toxic levels in refuge wetland ponds that are located mainly in hydrologically closed basins and thus act as concentrating disposal points. The depositional environment of the ponds may be similar to that of the nutrient-rich continental shelf edge and slope in which Cretaceous, Eocene, and Miocene sediments found to be seleniferous in the California Coast Ranges were deposited. Bioaccumulation may be therefore a primary mechanism of selenium enrichment in ancient sediments in addition to that of the formerly suggested Cretaceous volcanic pathway.

  2. ``The Kesterson effect''

    NASA Astrophysics Data System (ADS)

    Presser, Theresa S.

    1994-05-01

    Hypothesized to be derived from Cretaceous marine sedimentary rocks, selenium contamination of the Kesterson National Wildlife Refuge is traced through irrigation drainage to the source bedrock of the California Coast Ranges. This biogeochemical pathway of selenium is defined here as the “Kesterson effect.” At the refuge ponds, this effect culminated in 1983 in a 64% rate of deformity and death of embryos and hatchlings of wild aquatic birds. From the previous companion paper on irrigation drainage, the Kesterson effect has been implicated in nine of 11 reconnaissance areas studied in the western United States. Deformities have resulted in at least five of these sites. Climatic, geologic, hydrologic, and soil conditions in these reconnaissance areas are similar to those in the area surrounding Kesterson National Wildlife Refuge in the west-central San Joaquin Valley of California. In California, selenium, as selenate, was ultimately found weathered with sulfur from marine sources in soluble sodium and magnesium sulfate salts, which are concentrated by evaporation on farmland soils. The Se, mobilized by irrigation drainage, is bioaccumulated to toxic levels in refuge wetland ponds that are located mainly in hydrologically closed basins and thus act as concentrating disposal points. The depositional environment of the ponds may be similar to that of the nutrient-rich continental shelf edge and slope in which Cretaceous, Eocene, and Miocene sediments found to be seleniferous in the California Coast Ranges were deposited. Bioaccumulation may be therefore a primary mechanism of selenium enrichment in ancient sediments in addition to that of the formerly suggested Cretaceous volcanic pathway.

  3. Quantum Effects in Biology

    NASA Astrophysics Data System (ADS)

    Mohseni, Masoud; Omar, Yasser; Engel, Gregory S.; Plenio, Martin B.

    2014-08-01

    List of contributors; Preface; Part I. Introduction: 1. Quantum biology: introduction Graham R. Fleming and Gregory D. Scholes; 2. Open quantum system approaches to biological systems Alireza Shabani, Masoud Mohseni, Seogjoo Jang, Akihito Ishizaki, Martin Plenio, Patrick Rebentrost, Alàn Aspuru-Guzik, Jianshu Cao, Seth Lloyd and Robert Silbey; 3. Generalized Förster resonance energy transfer Seogjoo Jang, Hoda Hossein-Nejad and Gregory D. Scholes; 4. Multidimensional electronic spectroscopy Tomáš Mančal; Part II. Quantum Effects in Bacterial Photosynthetic Energy Transfer: 5. Structure, function, and quantum dynamics of pigment protein complexes Ioan Kosztin and Klaus Schulten; 6. Direct observation of quantum coherence Gregory S. Engel; 7. Environment-assisted quantum transport Masoud Mohseni, Alàn Aspuru-Guzik, Patrick Rebentrost, Alireza Shabani, Seth Lloyd, Susana F. Huelga and Martin B. Plenio; Part III. Quantum Effects in Higher Organisms and Applications: 8. Excitation energy transfer in higher plants Elisabet Romero, Vladimir I. Novoderezhkin and Rienk van Grondelle; 9. Electron transfer in proteins Spiros S. Skourtis; 10. A chemical compass for bird navigation Ilia A. Solov'yov, Thorsten Ritz, Klaus Schulten and Peter J. Hore; 11. Quantum biology of retinal Klaus Schulten and Shigehiko Hayashi; 12. Quantum vibrational effects on sense of smell A. M. Stoneham, L. Turin, J. C. Brookes and A. P. Horsfield; 13. A perspective on possible manifestations of entanglement in biological systems Hans J. Briegel and Sandu Popescu; 14. Design and applications of bio-inspired quantum materials Mohan Sarovar, Dörthe M. Eisele and K. Birgitta Whaley; 15. Coherent excitons in carbon nanotubes Leonas Valkunas and Darius Abramavicius; Glossary; References; Index.

  4. Interface effects on nanoelectronics

    NASA Astrophysics Data System (ADS)

    Conrad, Brad Richard

    2009-12-01

    Nanoelectronics consist of devices with active electronic components on the nanometer length scale. At such dimensions most, if not all, atoms or molecules composing the active device region must be on or near a surface. Also, materials effectively confined to two dimensions, or when subject to abrupt boundary conditions, generally do not behave the same as materials inside three dimensional, continuous structures. This dissertation is a quantitative determination of how surfaces and interfaces in organic nanoelectronic devices affect properties such as charge transport, electronic structure, and material fluctuations. Si/SiO2 is a model gate/gate dielectric for organic thin film transistors, therefore proper characterization and measurement of the effects of the SiO2/organic interface on device structures is extremely important. I fabricated pentacene thin film transistors on Si/SiO2 and varied the conduction channel thickness from effectively bulk (˜40nm) to 2 continuous conducting layers to examine the effect of substrate on noise generation. The electronic spectral noise was measured and the generator of the noise was determined to be due to the random spatial dependence of grain boundaries, independent of proximity to the gate oxide. This result led me to investigate the mechanisms of pentacene grain formation, including the role of small quantities of impurities, on silicon dioxide substrates. Through a series of nucleation, growth and morphology studies, I determined that impurities assist in nucleation on SiO2, decreasing the stable nucleus size by a third and increasing the overall number of grains. The pentacene growth and morphology studies prompted further exploration of pentacene crystal growth on SiO2. I developed a method of making atomically clean ultra-thin oxide films, with surface chemistry and growth properties similar to the standard thick oxides. These ultra-thin oxides were measured to be as smooth as cleaned silicon and then used as

  5. TEACHING PHYSICS: Capillary effects

    NASA Astrophysics Data System (ADS)

    Ivanov, Dragia; Petrova, Hristina

    2000-07-01

    We examine capillary tubes with a variable cross section, in which there is a column of fully wetting or fully non-wetting liquid. The direction in which the liquid moves when the tubes are placed horizontally is determined by means of Pascal's law. We promote the idea that the conical capillary tube is a hydraulic machine, whose two pistons are the liquid column's free surfaces, which have different radii. We propose a new way of demonstrating the described capillary effects by means of flat models of capillary tubes, constructed from glass plates. The demonstrations are presented in front of a large audience using an overhead projector.

  6. Earthquake occurrence and effects.

    PubMed

    Adams, R D

    1990-01-01

    Although earthquakes are mainly concentrated in zones close to boundaries of tectonic plates of the Earth's lithosphere, infrequent events away from the main seismic regions can cause major disasters. The major cause of damage and injury following earthquakes is elastic vibration, rather than fault displacement. This vibration at a particular site will depend not only on the size and distance of the earthquake but also on the local soil conditions. Earthquake prediction is not yet generally fruitful in avoiding earthquake disasters, but much useful planning to reduce earthquake effects can be done by studying the general earthquake hazard in an area, and taking some simple precautions. PMID:2347628

  7. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1997-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size resolved aerosol microphysics and chemistry. Both profiles included pollution haze layer from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core.

  8. Shock effects in meteorites

    NASA Technical Reports Server (NTRS)

    Stoeffler, D.; Bischoff, A.; Buchwald, V.; Rubin, A. E.

    1988-01-01

    The impacts that can occur between objects on intersecting solar system orbits can generate shock-induced deformations and transformations, creating new mineral phases or melting old ones. These shock-metamorphic effects affect not only the petrography but the chemical and isotopic properties and the ages of primordial meteoritic materials. A fuller understanding of shock metamorphism and breccia formation in meteorites will be essential not only in the study of early accretion, differentiation, and regolith-evolution processes, but in the characterization of the primordial composition of the accreted material itself.

  9. Microcircuit radiation effects databank

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This databank is the collation of radiation test data submitted by many testers and serves as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. It contains radiation sensitivity results from ground tests and is divided into two sections. Section A lists total dose damage information, and section B lists single event upset cross sections, I.E., the probability of a soft error (bit flip) or of a hard error (latchup).

  10. Substantial evidence of effect.

    PubMed

    Gould, A Lawrence

    2002-02-01

    Pressures for rapid drug development, especially for treatments that may affect public health significantly, drive a need to reconsider what is necessary to establish the "substantial evidence" of efficacy and safety required for regulatory approval. The concept of substantial evidence of effect can be stated fairly simply in principle, but its application to the evaluation of findings from real clinical drug development programs can be quite complicated and depend on circumstances relating to the population studied and the condition being treated. This paper discusses a number of considerations that arise in attempting to address this issue. These include confirmation of efficacy/safety as opposed to replication of results, the use of surrogates for the clinical outcome, ethical considerations, the use of trials aimed at demonstrating equivalence or noninferiority instead of superiority of a new drug, and the balance between benefits and risks. Recent developments such as the International Conference on Harmonization (ICH) guidelines dealing with statistical principles and choice of control group, and Food and Drug Administration (FDA) guidances interpreting the 1998 Modernization Act identify useful alternative definitions of substantial evidence and also identify when a single study can be enough to demonstrate a clinically important effect. The primary difficulty with the use of noninferiority trials is the need to demonstrate assay sensitivity or validity, i.e., that the trial would have demonstrated the superiority of the active control treatment to placebo had the trial included a placebo group. Failure to demonstrate a significant difference between the presumed active treatments and an inactive control precludes a definitive conclusion of assay validity, but external evidence, e.g., from trials demonstrating the activity of the active control, may yet justify concluding that the trial was assay valid. Issues of interpretation of important unexpected

  11. Holographic effective field theories

    NASA Astrophysics Data System (ADS)

    Martucci, Luca; Zaffaroni, Alberto

    2016-06-01

    We derive the four-dimensional low-energy effective field theory governing the moduli space of strongly coupled superconformal quiver gauge theories associated with D3-branes at Calabi-Yau conical singularities in the holographic regime of validity. We use the dual supergravity description provided by warped resolved conical geometries with mobile D3-branes. Information on the baryonic directions of the moduli space is also obtained by using wrapped Euclidean D3-branes. We illustrate our general results by discussing in detail their application to the Klebanov-Witten model.

  12. Environmental Effects of BPA

    PubMed Central

    Canesi, Laura

    2015-01-01

    Research on bisphenol A (BPA) as an environmental contaminant has now major regulatory implications toward the ecosystem health, and hence it is incumbent on scientists to do their research to the highest standards possible, in order that the most appropriate decisions are made to mitigate the impacts to aquatic wildlife. However, the contribution given so far appears rather fragmented. The present overview aims to collect available information on the effects of BPA on aquatic vertebrates and invertebrates to provide a general scenario and to suggest future developments toward more comprehensive approaches useful for aquatic species protection. PMID:26674307

  13. Ion propulsion cost effectivity

    NASA Technical Reports Server (NTRS)

    Zafran, S.; Biess, J. J.

    1978-01-01

    Ion propulsion modules employing 8-cm thrusters and 30-cm thrusters were studied for Multimission Modular Spacecraft (MMS) applications. Recurring and nonrecurring cost elements were generated for these modules. As a result, ion propulsion cost drivers were identified to be Shuttle charges, solar array, power processing, and thruster costs. Cost effective design approaches included short length module configurations, array power sharing, operation at reduced thruster input power, simplified power processing units, and power processor output switching. The MMS mission model employed indicated that nonrecurring costs have to be shared with other programs unless the mission model grows. Extended performance missions exhibited the greatest benefits when compared with monopropellant hydrazine propulsion.

  14. The online disinhibition effect.

    PubMed

    Suler, John

    2004-06-01

    While online, some people self-disclose or act out more frequently or intensely than they would in person. This article explores six factors that interact with each other in creating this online disinhibition effect: dissociative anonymity, invisibility, asynchronicity, solipsistic introjection, dissociative imagination, and minimization of authority. Personality variables also will influence the extent of this disinhibition. Rather than thinking of disinhibition as the revealing of an underlying "true self," we can conceptualize it as a shift to a constellation within self-structure, involving clusters of affect and cognition that differ from the in-person constellation. PMID:15257832

  15. Assessments of astronaut effectiveness

    NASA Technical Reports Server (NTRS)

    Rose, Robert M.; Helmreich, Robert L.; Fogg, Louis; Mcfadden, Terry J.

    1993-01-01

    This study examined the reliability and convergent validity of three methods of peer and supervisory ratings of the effectiveness of individual NASA astronauts and their relationships with flight assignments. These two techniques were found to be reliable and relatively convergent. Seniority and a peer-rated Performance and Competence factor proved to be most closely associated with flight assignments, while supervisor ratings and a peer-rated Group Living and Personality factor were found to be unrelated. Results have implications for the selection and training of astronauts.

  16. Hall Effect Imaging

    PubMed Central

    Shah, Jatin; Balaban, Robert S.

    2010-01-01

    This paper presents a new imaging method based on the classical Hall effect (HE), which describes the origin of a detectable voltage from a conductive object moving in a magnetic field. HE images are formed using ultrasound imaging techniques in a magnetic field. These images reflect the electrical properties of the sample. To demonstrate the feasibility of this method, images of plastic and biological samples are collected. The contrast mechanism and signal-to-noise issues are discussed. Since electrical parameters vary widely among tissue types and pathological states, HE imaging may be a useful tool for biological research and medical diagnosis. PMID:9444846

  17. Causal diagrams, the placebo effect, and the expectation effect

    PubMed Central

    Shahar, Eyal; Shahar, Doron J

    2013-01-01

    Using causal diagrams, a formal research methodology, we analyzed several definitions of placebo and the placebo effect. We conclude that placebo is an ambiguous, redundant term and that the so-called placebo effect conceals far more interesting effects that are attributed to the patient’s expectation. Biomedical research will benefit from abandoning the term placebo effect and focusing instead on a deeper understanding of the expectation variable, including its causes, effects, and effect modifiers. This avenue of research should be pursued by observational cohorts that are nested within clinical trials. PMID:24101881

  18. Microwave field effect transistor

    NASA Technical Reports Server (NTRS)

    Huang, Ho-Chung (Inventor)

    1989-01-01

    Electrodes of a high power, microwave field effect transistor are substantially matched to external input and output networks. The field effect transistor includes a metal ground plane layer, a dielectric layer on the ground plane layer, a gallium arsenide active region on the dielectric layer, and substantially coplanar spaced source, gate, and drain electrodes having active segments covering the active region. The active segment of the gate electrode is located between edges of the active segments of the source and drain electrodes. The gate and drain electrodes include inactive pads remote from the active segments. The pads are connected directly to the input and output networks. The source electrode is connected to the ground plane layer. The space between the electrodes and the geometry of the electrodes extablish parasitic shunt capacitances and series inductances that provide substantial matches between the input network and the gate electrode and between the output network and the drain electrode. Many of the devices are connected in parallel and share a common active region, so that each pair of adjacent devices shares the same source electrodes and each pair of adjacent devices shares the same drain electrodes. The gate electrodes for the parallel devices are formed by a continuous stripe that extends between adjacent devices and is connected at different points to the common gate pad.

  19. Meditation: Process and effects.

    PubMed

    Sharma, Hari

    2015-01-01

    Meditation has become popular in many Western nations, especially the USA. An increasing body of research shows various health benefits associated with meditation and these findings have sparked interest in the field of medicine. The practice of meditation originated in the ancient Vedic times of India and is described in the ancient Vedic texts. Meditation is one of the modalities used in Ayurveda (Science of Life), the comprehensive, natural health care system that originated in the ancient Vedic times of India. The term "meditation" is now loosely used to refer to a large number of diverse techniques. According to Vedic science, the true purpose of meditation is to connect oneself to one's deep inner Self. Techniques which achieve that goal serve the true purpose of meditation. Neurological and physiological correlates of meditation have been investigated previously. This article describes the process of meditation at a more fundamental level and aims to shed light on the deeper underlying mechanism of the beneficial effects associated with meditation. Research on the effects of meditation is summarized. PMID:27313408

  20. The Effective Equation Method

    NASA Astrophysics Data System (ADS)

    Kuksin, Sergei; Maiocchi, Alberto

    In this chapter we present a general method of constructing the effective equation which describes the behavior of small-amplitude solutions for a nonlinear PDE in finite volume, provided that the linear part of the equation is a hamiltonian system with a pure imaginary discrete spectrum. The effective equation is obtained by retaining only the resonant terms of the nonlinearity (which may be hamiltonian, or may be not); the assertion that it describes the limiting behavior of small-amplitude solutions is a rigorous mathematical theorem. In particular, the method applies to the three- and four-wave systems. We demonstrate that different possible types of energy transport are covered by this method, depending on whether the set of resonances splits into finite clusters (this happens, e.g. in case of the Charney-Hasegawa-Mima equation), or is connected (this happens, e.g. in the case of the NLS equation if the space-dimension is at least two). For equations of the first type the energy transition to high frequencies does not hold, while for equations of the second type it may take place. Our method applies to various weakly nonlinear wave systems, appearing in plasma, meteorology and oceanography.

  1. Conducting effective tailgate trainings.

    PubMed

    Harrington, David; Materna, Barbara; Vannoy, Jim; Scholz, Peter

    2009-07-01

    The California Department of Health Services' Occupational Health Branch and others have identified the construction industry as being at high risk for injuries, illnesses, and fatalities. Effective tailgate trainings (brief job site safety meetings) can be a powerful tool to promote hazard awareness and safe work practices. The authors found that many contractors and supervisors conducted ineffective tailgate trainings. They developed the BuildSafe California Project to assist contractors to have more effective programs by holding 25 training-of-trainers sessions reaching 1,525 participants. The needs assessment, intervention, and evaluation results from the first 18 trainings are presented. Eighty-six percent of the participants found the program "very helpful." Participants used the materials and made improvements in the quality and frequency of trainings. Supervisors must be skilled at conducting tailgate trainings as part of their responsibilities. There is a serious need to provide more culturally appropriate safety training in a workforce increasingly made up of Latino workers. PMID:18372431

  2. When Is Selection Effective?

    PubMed

    Gravel, Simon

    2016-05-01

    Deleterious alleles can reach high frequency in small populations because of random fluctuations in allele frequency. This may lead, over time, to reduced average fitness. In this sense, selection is more "effective" in larger populations. Recent studies have considered whether the different demographic histories across human populations have resulted in differences in the number, distribution, and severity of deleterious variants, leading to an animated debate. This article first seeks to clarify some terms of the debate by identifying differences in definitions and assumptions used in recent studies. We argue that variants of Morton, Crow, and Muller's "total mutational damage" provide the soundest and most practical basis for such comparisons. Using simulations, analytical calculations, and 1000 Genomes Project data, we provide an intuitive and quantitative explanation for the observed similarity in genetic load across populations. We show that recent demography has likely modulated the effect of selection and still affects it, but the net result of the accumulated differences is small. Direct observation of differential efficacy of selection for specific allele classes is nevertheless possible with contemporary data sets. By contrast, identifying average genome-wide differences in the efficacy of selection across populations will require many modeling assumptions and is unlikely to provide much biological insight about human populations. PMID:27010021

  3. Antiferromagnetic Spin Seebeck Effect.

    PubMed

    Wu, Stephen M; Zhang, Wei; Kc, Amit; Borisov, Pavel; Pearson, John E; Jiang, J Samuel; Lederman, David; Hoffmann, Axel; Bhattacharya, Anand

    2016-03-01

    We report on the observation of the spin Seebeck effect in antiferromagnetic MnF_{2}. A device scale on-chip heater is deposited on a bilayer of MnF_{2} (110) (30  nm)/Pt (4 nm) grown by molecular beam epitaxy on a MgF_{2} (110) substrate. Using Pt as a spin detector layer, it is possible to measure the thermally generated spin current from MnF_{2} through the inverse spin Hall effect. The low temperature (2-80 K) and high magnetic field (up to 140 kOe) regime is explored. A clear spin-flop transition corresponding to the sudden rotation of antiferromagnetic spins out of the easy axis is observed in the spin Seebeck signal when large magnetic fields (>9  T) are applied parallel to the easy axis of the MnF_{2} thin film. When the magnetic field is applied perpendicular to the easy axis, the spin-flop transition is absent, as expected. PMID:26991198

  4. Lake Effect Clouds

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The lake effect is particularly clear in this Sea-viewing Wide field-of-view Sensor (SeaWiFS) true-color image of the North American Great Lakes region, acquired December 5, 2000. Lakes Nipigon, Superior, and Michigan show striking contrasts between clear and cloudy air as the wind blows from the northwest across the lakes. As it flows across the relatively warm lakes, the cold dry air gathers heat and moisture from the surface. The warm moist air rises into the atmosphere and mixes vigorously with the cold dry air above. The layer of warm moist air deepens as it travels across the lake. Some of the evaporated water from the lake condenses into streamers of fog rising from the surface, while much of the moisture condenses to form a stratocumulus cloud in the upper half of the mixed layer. The cloud-forming water droplets may freeze into ice crystals and, due to accumulated water deposition over time, grow into snowflakes. This process can generate snowstorms that produce significant amounts of snowfall downwind. It is not uncommon for lake effect snowstorms to produce as much as two feet of snow within a 24-hour period in northwestern parts of New York and Pennsylvania. Image provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  5. Oblique effect in stereopsis?

    NASA Astrophysics Data System (ADS)

    Davis, Elizabeth T.; King, Robert A.; Anoskey, Alana M.

    1992-08-01

    Contrast thresholds are lower for detection of a vertical pattern than for an obliquely-oriented pattern. Is there an analogous oblique effect for the depth threshold of a stereoscopic luminance pattern? If so, why? Are the causes different from those for an oblique effect with monocular vision? To explore these issues, we used stereoscopic blurry bar (D6) luminance patterns with a peak spatial frequency of 2 or 4 cycles/degree (cpd) and either a vertical or an oblique orientation. We obtained psychometric functions for data obtained from a method of constant stimuli procedure, using 100 forced-choice trials for each datum. For each of three observers we estimated stereoacuity with a maximum-likelihood curve-fitting procedure. Subjects showed better stereoacuity for the vertical spatial patterns than for the oblique patterns. Some possible causes are that for oblique patterns (unlike vertical patterns) (1) the total vertical extent of the pattern is shrunk by a factor of sin((theta) ), where (theta) equals 90 degree(s) for vertical; (2) the pattern is 'stretched out' in the horizontal direction by a factor of csc((theta) ); (3) there are vertical as well as horizontal retinal disparities. Perhaps the resulting sparseness of horizontal disparity information or the potential vertical disparities in the oblique patterns reduce stereoacuity. To disentangle these causes, we used several different experimental conditions (e.g., elongation of oblique patterns) run in randomized blocks of trials. We will discuss these results and implications for stereopsis.

  6. Meditation: Process and effects

    PubMed Central

    Sharma, Hari

    2015-01-01

    Meditation has become popular in many Western nations, especially the USA. An increasing body of research shows various health benefits associated with meditation and these findings have sparked interest in the field of medicine. The practice of meditation originated in the ancient Vedic times of India and is described in the ancient Vedic texts. Meditation is one of the modalities used in Ayurveda (Science of Life), the comprehensive, natural health care system that originated in the ancient Vedic times of India. The term “meditation” is now loosely used to refer to a large number of diverse techniques. According to Vedic science, the true purpose of meditation is to connect oneself to one's deep inner Self. Techniques which achieve that goal serve the true purpose of meditation. Neurological and physiological correlates of meditation have been investigated previously. This article describes the process of meditation at a more fundamental level and aims to shed light on the deeper underlying mechanism of the beneficial effects associated with meditation. Research on the effects of meditation is summarized. PMID:27313408

  7. An effective Z'

    SciTech Connect

    Fox, Patrick J.; Liu, Jia; Tucker-Smith, David; Weiner, Neal

    2011-12-06

    We describe a method to couple Z' gauge bosons to the standard model (SM), without charging the SM fields under the U(1)', but instead through effective higher-dimension operators. This method allows complete control over the tree-level couplings of the Z' and does not require altering the structure of any of the SM couplings, nor does it contain anomalies or require introduction of fields in nonstandard SM representations. Moreover, such interactions arise from simple renormalizable extensions of the SM—the addition of vectorlike matter that mixes with SM fermions when the U(1)' is broken. We apply effective Z' models as explanations of various recent anomalies: the D0 same-sign dimuon asymmetry, the CDF W+di-jet excess and the CDF top forward-backward asymmetry. In the case of the W+di-jet excess we also discuss several complementary analyses that may shed light on the nature of the discrepancy. We consider the possibility of non-Abelian groups, and discuss implications for the phenomenology of dark matter as well.

  8. Ecotoxicological effects extrapolation models

    SciTech Connect

    Suter, G.W. II

    1996-09-01

    One of the central problems of ecological risk assessment is modeling the relationship between test endpoints (numerical summaries of the results of toxicity tests) and assessment endpoints (formal expressions of the properties of the environment that are to be protected). For example, one may wish to estimate the reduction in species richness of fishes in a stream reach exposed to an effluent and have only a fathead minnow 96 hr LC50 as an effects metric. The problem is to extrapolate from what is known (the fathead minnow LC50) to what matters to the decision maker, the loss of fish species. Models used for this purpose may be termed Effects Extrapolation Models (EEMs) or Activity-Activity Relationships (AARs), by analogy to Structure-Activity Relationships (SARs). These models have been previously reviewed in Ch. 7 and 9 of and by an OECD workshop. This paper updates those reviews and attempts to further clarify the issues involved in the development and use of EEMs. Although there is some overlap, this paper does not repeat those reviews and the reader is referred to the previous reviews for a more complete historical perspective, and for treatment of additional extrapolation issues.

  9. An effective Z'

    DOE PAGESBeta

    Fox, Patrick J.; Liu, Jia; Tucker-Smith, David; Weiner, Neal

    2011-12-06

    We describe a method to couple Z' gauge bosons to the standard model (SM), without charging the SM fields under the U(1)', but instead through effective higher-dimension operators. This method allows complete control over the tree-level couplings of the Z' and does not require altering the structure of any of the SM couplings, nor does it contain anomalies or require introduction of fields in nonstandard SM representations. Moreover, such interactions arise from simple renormalizable extensions of the SM—the addition of vectorlike matter that mixes with SM fermions when the U(1)' is broken. We apply effective Z' models as explanations ofmore » various recent anomalies: the D0 same-sign dimuon asymmetry, the CDF W+di-jet excess and the CDF top forward-backward asymmetry. In the case of the W+di-jet excess we also discuss several complementary analyses that may shed light on the nature of the discrepancy. We consider the possibility of non-Abelian groups, and discuss implications for the phenomenology of dark matter as well.« less

  10. Radiation effects in space.

    PubMed

    Fry, R J

    1986-01-01

    The radiation protection guidelines of the National Aeronautics and Space Administration (NASA) are under review by Scientific Committee 75 of the National Council Protection and Measurements. The re-evaluation of the current guidelines is necessary, first, because of the increase in information about radiation risks since 1970 when the original recommendations were made and second, the population at risk has changed. For example, women have joined the ranks of the astronauts. Two types of radiation, protons and heavy ions, are of particular concern in space. Unfortunately, there is less information about the effects on tissues and cancer by these radiations than by other radiations. The choice of Quality Factors (Q) for obtaining dose equivalents for these radiations, is an important aspect of the risk estimate for space travel. There are not sufficient data for the induction of late effects by either protons or by heavy ions. The current information suggests a RBE for the relative protons of about 1, whereas, a RBE of 20 for tumor induction by heavy ions, such as iron-56, appears appropriate. The recommendations for the dose equivalent career limits for skin and the lens of the eye have been reduced but the 30-day and annual limits have been raised. PMID:11537230

  11. Radiation effects in space

    NASA Astrophysics Data System (ADS)

    Fry, R. J. M.

    The radiation protection guidelines of the National Aeronautics and Space Administration (NASA) are under review by Scientific Committe 75 of the National Council on Radiation Protection and Measurements. The re-evaluation of the current guidelines is necessary, first, because of the increase in information about radiation risks since 1970 when the original recommendations were made and second, the population at risk has changed. For example, women have joined the ranks of the astronauts. Two types of radiation, protons and heavy ions, are of particular concern in space. Unfortunately, there is less information about the effects on tissues and the induction of cancer by these radiations than by other radiations. The choice of Quality Factors (Q) for obtaining dose equivalents for these radiations, is an important aspect of the risk estimate for space travel. There are not sufficient data for the induction of late effects by either protons or by heavy ions. The current information suggests a RBE for the relative protons of about 1, whereas, -a RBE of 20 for tumor induction by heavy ions, such as iron-56, appears appropriate. The recommendations for the dose equivalent career limits for skin and the lens of the eye have been reduced but the 30-day and annual limits have been raised.

  12. Behavioral effects of microwaves

    SciTech Connect

    Stern, S.

    1980-01-01

    Microwaves can produce sensations of warmth and sound in humans. In other species, they also can serve as cues, they may be avoided, and they can disrupt ongoing behavior. These actions appear to be due to heat produced by energy absorption. The rate of absorption depends on the microwave parameters and the electrical and geometric properties of the subject. We therefore, cannot predict the human response to microwaves based on data from other animals without appropriate scaling considerations. At low levels of exposure, microwaves can produce changes in behavior without large, or even measureable, changes in body temperature. Thermoregulatory behavior may respond to those low levels of heat, and thereby affect other behavior occurring concurrently. There are no data that demonstrate that behavioral effects of microwaves depend on any mechanism other than reactions to heat. Our interpretation of whether a reported behavioral effect indicates that microwaves may be hazardous depends on our having a complete description of the experiment and on our criteria of behavioral toxicity.

  13. The Creative Stereotype Effect.

    PubMed

    Dumas, Denis; Dunbar, Kevin N

    2016-01-01

    Because of its fundamental relevance to scientific innovation, artistic expression, and human ingenuity, creativity has long been the subject of systematic psychological investigation. Concomitantly, the far-reaching effects of stereotypes on various cognitive and social processes have been widely researched. Bridging these two literatures, we show in a series of two studies that stereotypes related to creativity can both enhance and diminish individuals' performance on a divergent thinking task. Specifically, Study 1 demonstrated that participants asked to take on a stereotypically uninhibited perspective performed significantly better on a divergent thinking task than those participants who took on a stereotypically inhibited perspective, and a control group. Relatedly, Study 2 showed that the same effect is found within-subjects, with divergent thinking significantly improving when participants invoke an uninhibited stereotype. Moreover, we demonstrate the efficacy of Latent Semantic Analysis as an objective measure of the originality of ideas, and discuss implications of our findings for the nature of creativity. Namely, that creativity may not be best described as a stable individual trait, but as a malleable product of context and perspective. PMID:26863143

  14. Pupillary Stroop effects

    PubMed Central

    Ørbo, Marte; Holmlund, Terje; Miozzo, Michele

    2010-01-01

    We recorded the pupil diameters of participants performing the words’ color-naming Stroop task (i.e., naming the color of a word that names a color). Non-color words were used as baseline to firmly establish the effects of semantic relatedness induced by color word distractors. We replicated the classic Stroop effects of color congruency and color incongruency with pupillary diameter recordings: relative to non-color words, pupil diameters increased for color distractors that differed from color responses, while they reduced for color distractors that were identical to color responses. Analyses of the time courses of pupil responses revealed further differences between color-congruent and color-incongruent distractors, with the latter inducing a steep increase of pupil size and the former a relatively lower increase. Consistent with previous findings that have demonstrated that pupil size increases as task demands rise, the present results indicate that pupillometry is a robust measure of Stroop interference, and it represents a valuable addition to the cognitive scientist’s toolbox. PMID:20865297

  15. The Creative Stereotype Effect

    PubMed Central

    Dumas, Denis; Dunbar, Kevin N.

    2016-01-01

    Because of its fundamental relevance to scientific innovation, artistic expression, and human ingenuity, creativity has long been the subject of systematic psychological investigation. Concomitantly, the far-reaching effects of stereotypes on various cognitive and social processes have been widely researched. Bridging these two literatures, we show in a series of two studies that stereotypes related to creativity can both enhance and diminish individuals’ performance on a divergent thinking task. Specifically, Study 1 demonstrated that participants asked to take on a stereotypically uninhibited perspective performed significantly better on a divergent thinking task than those participants who took on a stereotypically inhibited perspective, and a control group. Relatedly, Study 2 showed that the same effect is found within-subjects, with divergent thinking significantly improving when participants invoke an uninhibited stereotype. Moreover, we demonstrate the efficacy of Latent Semantic Analysis as an objective measure of the originality of ideas, and discuss implications of our findings for the nature of creativity. Namely, that creativity may not be best described as a stable individual trait, but as a malleable product of context and perspective. PMID:26863143

  16. Microwave biological effects: an overview

    SciTech Connect

    Michaelson, S.M.

    1980-01-01

    Research concerning the biological effects of microwave (MW) exposure is reviewed. Areas examined include the principles and concepts related to biologic experiments and interpretation, cellular effects, chromosomes-genetic effects, effects on the nervous system, behavioral effects, effects on immunity, and the health aspects of MW exposure. Many of the investigations suffer from either inadequacies of technical facilities and energy measurement skills or insufficient control of the biological specimens and the criteria for biological change. There is a need for systematic and quantitative comparative investigations, using well-controlled experiments.

  17. Hilbert Space Effect-Representations of Effect Algebras

    NASA Astrophysics Data System (ADS)

    Riečanová, Z.; Zajac, M.

    2012-12-01

    In answer to open questions (posed in [12]) we prove that an effect algebra has a Hilbert space effect-representation iff E possesses an ordering set of states. These are, up to isomorphism, all intervals and all their sub-effect algebras in the set of all positive linear operators on any Hilbert space H. Nevertheless, there are effect algebras E, elements of which are linear operators in a Hilbert space, but E does not have such a representation.

  18. Effect Sizes, Confidence Intervals, and Confidence Intervals for Effect Sizes

    ERIC Educational Resources Information Center

    Thompson, Bruce

    2007-01-01

    The present article provides a primer on (a) effect sizes, (b) confidence intervals, and (c) confidence intervals for effect sizes. Additionally, various admonitions for reformed statistical practice are presented. For example, a very important implication of the realization that there are dozens of effect size statistics is that "authors must…

  19. 75 FR 10411 - Borrower Rights; Effective Interest Rates; Effective Date

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-08

    ... Agency), through the FCA Board (Board), issued a final rule under part 617 on December 22, 2009 (74 FR... CFR part 617 published on December 22, 2009 (74 FR 67970) is effective March 2, 2010. FOR FURTHER... 12 CFR Part 617 RIN 3052-AC45 Borrower Rights; Effective Interest Rates; Effective Date AGENCY:...

  20. Anomeric Effects in Sulfamides.

    PubMed

    Hansen, Eric; Limé, Elaine; Norrby, Per-Ola; Wiest, Olaf

    2016-05-26

    Sulfamides, together with their simpler sulfonamide analogs, are common functional groups in a significant number of biologically active compounds. This is partly due to their unique electronic structure and conformational behavior, which mimics the tetrahedral intermediate involved in many proteases, esterases, and related enzymes. Here, the origin of these unique structural elements are analyzed in the context of a coupled, double anomeric effect using DFT calculations, including conformational scans, and NBO analysis. It is shown that these coupled interactions can be implicitly parametrized in MM3* type force fields using the quantum-guided molecular mechanics (Q2MM) method, yielding accurate force field parameters for molecular mechanics studies of sulfamides and sulfonamides. PMID:27135551

  1. The Energy Diameter Effect

    SciTech Connect

    Souers, P; Vitello, P; Garza, R; Hernandez, A

    2007-04-20

    Various relations for the detonation energy and velocity as they relate to the inverse radius of the cylinder are explored. The detonation rate-inverse slope relation seen in reactive flow models can be used to derive the familiar Eyring equation. Generalized inverse radii can be shown to fit large quantities of cylinder and sphere results. A rough relation between detonation energy and detonation velocity is found from collected JWL values. Cylinder test data for ammonium nitrate mixes down to 6.35 mm radii are presented, and a size energy effect is shown to exist in the Cylinder test data. The relation that detonation energy is roughly proportional to the square of the detonation velocity is shown by data and calculation.

  2. Symmetry Effects in Computation

    NASA Astrophysics Data System (ADS)

    Yao, Andrew Chi-Chih

    2008-12-01

    The concept of symmetry has played a key role in the development of modern physics. For example, using symmetry, C.N. Yang and other physicists have greatly advanced our understanding of the fundamental laws of physics. Meanwhile, computer scientists have been pondering why some computational problems seem intractable, while others are easy. Just as in physics, the laws of computation sometimes can only be inferred indirectly by considerations of general principles such as symmetry. The symmetry properties of a function can indeed have a profound effect on how fast the function can be computed. In this talk, we present several elegant and surprising discoveries along this line, made by computer scientists using symmetry as their primary tool. Note from Publisher: This article contains the abstract only.

  3. Dynamic effects of combustion

    NASA Technical Reports Server (NTRS)

    Oppenheim, A. K.

    1982-01-01

    The dynamic effects of combustion are due to the evolution of exothermic energy and its deposition in the compressible medium where the process takes place. The paper examines the dynamics of combustion phenomena, including ignition, turbulent flame propagation (inflammation), explosion, and detonation, with emphasis on their exothermic characteristics. Ignition and explosion are treated as problems of nonlinear mechanics, and their dynamic behavior is described in terms of phase space models and cinematographic laser shear interferograms. The results of a numerical random vortex model of turbulent flame propagation are confirmed in a combustion tunnel experiment, where it was observed that a fresh mixture of burnt and unburnt gases can sustain combustion with a relatively small expenditure of overall mass flow, due to the increasing specific volume of burnt gases inside the flame front. An isentropic pressure wave is found to precede the accelerating flame in the process of detonation, and components of this presssure wave are shown to propagate at local sonic velocities.

  4. [Are antidepressants really effective?].

    PubMed

    Ammendola, S; Kornreich, C

    2015-01-01

    Antidepressants are widely used for a long time and it is estimated that about 10 % of the belgian population is taking some of them each year. However, there are important controversies about their real efficacy. We review successively arguments for and against their efficacy. On the one hand, meta-analysis have shown no big efficacy differences between antidepressants and placebo. On the other hand, those meta-analysis have been criticized for their methodology. Animal models show a real effect of antidepressants on the brain and clinical observations, such as an impact on suicide prevention, the possibility of induced manic switch, and an efficacy on anxiety disorders are in favour of a real efficacy. Given our current state of knowledge about them it seems appropriate to continue to use anti-depressants in the treatment of depressive patients. PMID:26749632

  5. Effective consultation in nursing.

    PubMed

    McCutcheon, S; Perkin, K

    1996-01-01

    Given the fiscal challenges within health care today, nurse administrators, whether acting in the role of client or consultant, must determine the most effective and efficient way to solve problems and achieve goals. The consultation process can be viewed from both the client's and the consultant's perspective. This article is intended to provide a practical approach to addressing the issues within the consultation process. The steps of the consultation process are reviewed. The evolution from solving problems to achieving goals is described. The importance of the use of a screening tool when interviewing prospective consultants is emphasized and an example of a generic screening tool is provided. During the interview, consultants are advised to clearly determine the problem or goal, the outcomes which the client expects, possible barriers and risks, and the philosophical fit between both parties. Nurses practise consultation skills daily and, therefore, consultation is a viable opportunity for self-employment. PMID:8695611

  6. Alcohol's effect on lactation.

    PubMed

    Mennella, J

    2001-01-01

    Although pregnant women are discouraged from drinking alcohol because of alcohol's detrimental effect on fetal development, the lore of many cultures encourages lactating women to drink alcohol to optimize breast milk production and infant nutrition. In contrast to this folklore, however, studies demonstrate that maternal alcohol consumption may slightly reduce milk production. Furthermore, some of the alcohol consumed by a lactating woman is transferred to her milk and thus consumed by the infant. This alcohol consumption may adversely affect the infant's sleep and gross motor development and influence early learning about alcohol. Based on this science, it would seem that the recommendation for a nursing mother to drink a glass of beer or wine shortly before nursing may actually be counterproductive. PMID:11810962

  7. Action languages: Dimensions, effects

    NASA Technical Reports Server (NTRS)

    Hayes, Daniel G.; Streeter, Gordon

    1989-01-01

    Dimensions of action languages are discussed for communication between humans and machines, and the message handling capabilities of object oriented programming systems are examined. Design of action languages is seen to be very contextual. Economical and effective design will depend on features of situations, the tasks intended to be accomplished, and the nature of the devices themselves. Current object oriented systems turn out to have fairly simple and straightforward message handling facilities, which in themselves do little to buffer action or even in some cases to handle competing messages. Even so, it is possible to program a certain amount of discretion about how they react to messages. Such thoughtfulness and perhaps relative autonomy of program modules seems prerequisite to future systems to handle complex interactions in changing situations.

  8. THE HOT CHOCOLATE EFFECT

    SciTech Connect

    Crawford, Frank S.

    1980-12-01

    The "hot chocolate effect" was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the ten percent accuracy of the experiments.

  9. Hot chocolate effect

    SciTech Connect

    Crawford, F.S.

    1982-05-01

    The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

  10. Radiation Effects In Space

    SciTech Connect

    Tripathi, Ram K.

    2011-06-01

    Protecting space missions from severe exposures from radiation, in general, and long duration/deep space human missions, in particular, is a critical design driver, and could be a limiting factor. The space radiation environment consists of galactic cosmic rays (GCR), solar particle events (SPE), trapped radiation, and includes ions of all the known elements over a very broad energy range. These ions penetrate spacecraft materials producing nuclear fragments and secondary particles that damage biological tissues and microelectronic devices. One is required to know how every element (and all isotopes of each element) in the periodic table interacts and fragments on every other element in the same table as a function of kinetic energy ranging over many decades. In addition, the accuracy of the input information and database, in general and nuclear data in particular, impacts radiation exposure health assessments and payload penalty. After a brief review of effects of space radiation on materials and electronics, human space missions to Mars is discussed.

  11. TOWARD MORE EFFECTIVE REGULATION

    SciTech Connect

    J. GRAF

    2000-06-01

    This paper proposes a model relationship between the operator engaged in a hazardous activity, the regulator of that activity, and the general public. The roles and responsibilities of each entity are described in a way that allows effective communication flow. The role of the regulator is developed using the steam boiler as an example of a hazard subject to regulation; however, the model applies to any regulated activity. In this model the safety analyst has the extremely important role of communicating sometimes difficult technical information to the regulator in a way that the regulator can provide credible assurance to the general public as to the adequacy of the control of the hazardous activity. The conclusion asserts that acceptance of the model, understanding of the roles and responsibilities and definition of who communicates what information to whom will mitigate frustration on the part of each of the three entities.

  12. Radiation Effects in Graphite

    SciTech Connect

    Burchell, Timothy D

    2012-01-01

    The requirements for a solid moderator are reviewed and the reasons that graphite has become the solid moderator of choice discussed. The manufacture and properties of some currently available near-isotropic and isotropic grades are described. The major features of a graphite moderated reactors are briefly outlined. Displacement damage and the induced structural and dimensional changes in graphite are described. Recent characterization work on nano-carbons and oriented pyrolytic graphites that have shed new light on graphite defect structures are reviewed, and the effect of irradiation temperature on the defect structures is highlighted. Changes in the physical properties of nuclear graphite caused by neutron irradiation are reported. Finally, the importance of irradiation induced creep is presented, along with current models and their deficiencies.

  13. Hydrodynamic effects on coalescence.

    SciTech Connect

    Dimiduk, Thomas G.; Bourdon, Christopher Jay; Grillet, Anne Mary; Baer, Thomas A.; de Boer, Maarten Pieter; Loewenberg, Michael; Gorby, Allen D.; Brooks, Carlton, F.

    2006-10-01

    The goal of this project was to design, build and test novel diagnostics to probe the effect of hydrodynamic forces on coalescence dynamics. Our investigation focused on how a drop coalesces onto a flat surface which is analogous to two drops coalescing, but more amenable to precise experimental measurements. We designed and built a flow cell to create an axisymmetric compression flow which brings a drop onto a flat surface. A computer-controlled system manipulates the flow to steer the drop and maintain a symmetric flow. Particle image velocimetry was performed to confirm that the control system was delivering a well conditioned flow. To examine the dynamics of the coalescence, we implemented an interferometry capability to measure the drainage of the thin film between the drop and the surface during the coalescence process. A semi-automated analysis routine was developed which converts the dynamic interferogram series into drop shape evolution data.

  14. The Energy Diameter Effect

    SciTech Connect

    Vitello, P; Garza, R; Hernandez, A; Souers, P C

    2007-07-10

    We explore various relations for the detonation energy and velocity as they relate to the inverse radius of the cylinder. The detonation rate-inverse slope relation seen in reactive flow models can be used to derive the familiar Eyring equation. Generalized inverse radii can be shown to fit large quantities of cylinder results. A rough relation between detonation energy and detonation velocity is found from collected JWL values. Cylinder test data for ammonium nitrate mixes down to 6.35 mm radii are presented, and a size energy effect is shown to exist in the Cylinder test data. The relation that detonation energy is roughly proportional to the square of the detonation velocity is shown by data and calculation.

  15. Effective monitoring of agriculture.

    PubMed

    Lindenmayer, David B; Likens, Gene E

    2011-06-01

    An opinion piece published in Nature proposed a global network for agricultural monitoring [J. Sachs, R. Remans, S. Smukler, L. Winowiecki, S. J. Andelman, K. G. Cassman, D. Castle, R. DeFries, G. Denning, J. Fanzo, L. E. Jackson, R. Leemans, J. Leemans, J. C. Milder, S. Naeem, G. Nziguheba, C. A. Palm, J. P. Reganold, D. D. Richter, S. J. Scherr, J. Sircely, C. Sullivan, T. P. Tomich and P. A. Sanchez, Nature, 2010, 466, 558-560.]. Whilst we agree with Sachs et al. that monitoring of agricultural systems is a critically important activity of global significance, especially given increasing problems with global food security and the potential impacts of agriculture on the environment [J. Cribb, The Coming Famine. The Global Food Crisis and What We Can Do to Avoid It, CSIRO Publishing and University of California Press, Melbourne and Oakland, 2010.], we argue in this paper that their generic, mandated monitoring framework has a high probability of failure or at best will be highly inefficient. We base this conclusion on our recently published examination of the factors influencing the success or failure of monitoring programs worldwide [D. B. Lindenmayer and G. E. Likens, Effective Ecological Monitoring, CSIRO Publishing and Earthscan, Melbourne and London, 2010.]. We briefly outline what we believe are three serious flaws in the monitoring framework proposed by Sachs et al. We then suggest an alternative approach that we argue would be more effective, more efficient, and have a greater chance of successfully addressing key issues in sustainable agriculture. PMID:21479312

  16. Radiative Effects of Aerosols

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.

    1996-01-01

    During the Atlantic Stratocumulus Transition Experiment (ASTEX) in June 1992, two descents in cloud-free regions allowed comparison of the change in aerosol optical depth as determined by an onboard total-direct-diffuse radiometer (TDDR) to the change calculated from measured size-resolved aerosol microphysics and chemistry. Both profiles included a pollution haze from Europe but the second also included the effect of a Saharan dust layer above the haze. The separate contributions of supermicrometer (coarse) and submicrometer (fine) aerosol were determined and thermal analysis of the pollution haze indicated that the fine aerosol was composed primarily of a sulfate/water mixture with a refractory soot-like core. The soot core increased the calculated extinction by about 10% in the most polluted drier layer relative to a pure sulfate aerosol but had significantly less effect at higher humidities. A 3 km descent through a boundary layer air mass dominated by pollutant aerosol with relative humidities (RH) 10-77% yielded a close agreement between the measured and calculated aerosol optical depths (550 nm) of 0.160 (+/- 0.07) and 0. 157 (+/- 0.034) respectively. During descent the aerosol mass scattering coefficient per unit sulfate mass varied from about 5 to 16 m(exp 2)/g and primarily dependent upon ambient RH. However, the total scattering coefficient per total fine mass was far less variable at about 4+/- 0.7 m(exp 2)/g. A subsequent descent through a Saharan dust layer located above the pollution aerosol layer revealed that both layers contributed similarly to aerosol optical depth. The scattering per unit mass of the coarse aged dust was estimated at 1.1 +/- 0.2 m(exp 2)/g. The large difference (50%) in measured and calculated optical depth for the dust layer exceeded measurements.

  17. Aluminum toxicity. Hematological effects.

    PubMed

    Mahieu, S; del Carmen Contini, M; Gonzalez, M; Millen, N; Elias, M M

    2000-01-01

    Sequential effects of intoxication with aluminum hydroxide (Al) (80 mg/Kg body weight, i.p., three times a week), were studied on rats from weaning and up to 28 weeks. The study was carried out on hematological and iron metabolism-related parameters on peripheral blood, at the end of the 1st, 2nd, 3rd, 4th, 5th and 6th months of exposure. As it was described that hematotoxic effects of Al are mainly seen together with high levels of uremia, renal function was measured at the same periods. The animals treated developed a microcytosis and was accompanied by a decrease in mean corpuscular hemoglobin (MCH). Significantly lower red blood cell counts (RBC million/microl) were found in rats treated during the 1st month. These values matched those obtained for control rats during the 2nd month. From the 3rd month onwards, a significant increase was observed as compared to control groups, and the following values were obtained by the 6th month: (T) 10.0 +/- 0.3 versus (C) 8.7 +/- 0.2 (million/microl). Both MCH and mean corpuscular volume (MCV) were found to be significantly lower in groups treated from the 2nd month. At the end of the 6th month the following values were found: MCH (T) 13.3 +/- 0.1 versus (C) 16.9 +/- 0.3 (pg); MCV (T) 42.1 +/- 0.7 versus (C) 51.8 +/- 0.9 (fl). Al was found responsible for lower serum iron concentration levels and in the percentage of transferrin saturation. Thus, although microcytic anemia constitutes an evidence of chronic aluminum exposure, prolonged exposure could lead to a recovery of hematocrit and hemoglobin concentration values with an increase in red cell number. Nevertheless, both microcytosis and the decrease of MCH would persist. These modifications took place without changes being observed in the renal function during the observation period. PMID:10643868

  18. Hall Effect in a Plasma.

    ERIC Educational Resources Information Center

    Kunkel, W. B.

    1981-01-01

    Describes an apparatus and procedure for conducting an undergraduate laboratory experiment to quantitatively study the Hall effect in a plasma. Includes background information on the Hall effect and rationale for conducting the experiment. (JN)

  19. Union Effects on Teacher Productivity.

    ERIC Educational Resources Information Center

    Eberts, Randall W.

    1984-01-01

    This paper examines the effect of collective bargaining on several factors known to be determinants of student achievement in the public schools, particularly its effect on the teacher's allocation of time among various activities. (Author/SSH)

  20. Further considerations of spallation effects

    NASA Technical Reports Server (NTRS)

    Dyer, C.

    1973-01-01

    Trapped photon and cosmic ray effects on spallation in the UK-5 (hard X ray telescope) central crystal were measured. Both low dose and high dose effects were considered. Decay results are presented in tables.

  1. Managing Chemotherapy Side Effects: Infection

    MedlinePlus

    ... ational C ancer I nstitute Managing Chemotherapy Side Effects Infection “I am extra careful to stay away ... doctor or nurse right away. Managing Chemotherapy Side Effects: Infection Take these steps to lower your chances ...

  2. Managing Chemotherapy Side Effects: Diarrhea

    MedlinePlus

    ... ational C ancer I nstitute Managing Chemotherapy Side Effects U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES National ... before taking medicine for diarrhea. Managing Chemotherapy Side Effects: Diarrhea These foods and drinks may help if ...

  3. The nocebo effect: patient expectations and medication side effects.

    PubMed

    Faasse, Kate; Petrie, Keith J

    2013-09-01

    Expectation of treatment side effects is consistently linked with those symptoms being realised. Patient expectations, including those generated by the informed consent process, can have a large influence on the side effects that patients feel after starting a new medical treatment. Such symptoms may be the result of the nocebo effect, whereby the expectation of side effects leads to them being experienced. Side effects may also be due to the misattribution of pre-existing or unrelated symptoms to the new medication. Medical professionals' own negative beliefs about a treatment, especially generic drugs, may further enhance patients' expectations of adverse effects. The news media may also influence expectations, particularly when media attention is directed towards a health or medication scare. This field of research has ethical and clinical implications for both medical professionals and the news media with respect to the level and type of information about treatment side effects that is provided to patients or members of the public. PMID:23842213

  4. Effective Programs for Latino Students.

    ERIC Educational Resources Information Center

    Slavin, Robert E., Ed.; Calderon, Margarita, Ed.

    This collection of papers presents the current state of research on effective instructional programs for Hispanic American students. The 10 chapters are: (1) "Effective Programs for Latino Students in Elementary and Middle Schools" (Olatokunbo S. Fashola, Robert E. Slavin, Margarita Calderon, and Richard Duran); (2) "Effective Dropout Prevention…

  5. Teaching Effectiveness: Making the Case.

    ERIC Educational Resources Information Center

    Cochran, Leslie H.; Moodie, Clara Lee

    1978-01-01

    Teaching effectiveness is assuming greater importance in academic decision making in higher education. Guidelines are suggested for devising quantifiable means of demonstrating teaching effectiveness and for resolving the dilemma of faculty and administration for presenting data in support of teaching effectiveness. (JMF)

  6. Attention and the Testing Effect

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Picklesimer, Milton

    2016-01-01

    Memory retrieval often enhances still later memory as evidenced by the testing effect. Divided attention (DA) is known to produce different effects on encoding and retrieval, substantially disrupting the former and often producing little effect on the latter. The present experiments examine whether the mnemonic consequences of retrieval are…

  7. Cognitive Constraints and Island Effects

    ERIC Educational Resources Information Center

    Hofmeister, Philip; Sag, Ivan A.

    2010-01-01

    Competence-based theories of island effects play a central role in generative grammar, yet the graded nature of many syntactic islands has never been properly accounted for. Categorical syntactic accounts of island effects have persisted in spite of a wealth of data suggesting that island effects are not categorical in nature and that…

  8. HIV Medicines and Side Effects

    MedlinePlus

    Side Effects of HIV Medicines HIV Medicines and Side Effects (Last updated 1/7/2016; last reviewed 1/7/2016) Key Points HIV medicines help people with ... will depend on a person’s individual needs. Can HIV medicines cause side effects? HIV medicines help people ...

  9. The Enigma of Organizational Effectiveness.

    ERIC Educational Resources Information Center

    Cameron, Kim

    1981-01-01

    Organizational effectiveness is not a clearly defined concept. The author illustrates how the four most widely used models are not uniformly applicable. He states the evaluator must make explicit certain critical choices when measuring effectiveness. These criteria reveal the definition of effectiveness and what is being measured. (DWH)

  10. Assessing and Improving Institutional Effectiveness.

    ERIC Educational Resources Information Center

    Cameron, Kim S.

    Information to promote assessment of organizational effectiveness in colleges and universities is presented, along with an exercise to rank the effectiveness of 10 institutions. The exercise uses three types of criteria to indicate effectiveness: subjective ratings, data about students and activities, and institutional capacity and financial…

  11. Anomalous Hall effect

    NASA Astrophysics Data System (ADS)

    Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.

    2010-04-01

    The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a

  12. Effects of Security actions

    NASA Astrophysics Data System (ADS)

    Bergman, Ramona; Andersson-Sköld, Yvonne; Nyberg, Lars; Johansson, Magnus

    2010-05-01

    In a project funded by the Swedish Civil Contingencies Agency, the effort and work to reduce different kinds of accidents are being evaluated. The project wants to illuminate the links between actions and outcome, so we can learn from today's performance and in the future select more effective measures and overall deal with accidents more efficiently. The project ESS covers the field of frequent accidents such as sliding accidents at home, in house fires and less common accidents such as chemical and land fill accidents up to even more rare accidents such as natural accidents and hazards. In the ESS project SGI (Swedish geotechnical institute) will evaluate the work and effort concerning various natural hazards limited to landslides, erosion and flooding. The aim is to investigate how municipalities handle, especially prevention, of such natural disasters today. The project includes several aspects such as: • which are the driving forces for risk analysis in a municipality • do one use risk mapping (and what type) in municipal risk analysis • which aspects are most important when selecting preventive measures • in which way do one learn from past accidents • and from previous accidents elsewhere, by for example use existing databases • etc There are many aspects that play a role in a well-functioning safety promotion work. The overall goal is to examine present work and activities, highlight what is well functioning and identify weak points. The aim is to find out where more resources are needed and give suggestions for a more efficient security work. This includes identification of the most efficient "tools" in use or needed. Such tools can be education, directives, funding, more easily available maps and information regarding previous accidents and preventive measures etc. The project will result in recommendations for more effective ways to deal with landslides, erosion and flooding. Since different kinds of problems can occur depending on level of

  13. Effective Physics Study Habits

    NASA Astrophysics Data System (ADS)

    Zettili, Nouredine

    2011-04-01

    We discuss the methods of efficient study habits and how they can be used by students to help them improve learning physics. In particular, we deal with ideas pertaining to the most effective techniques needed to help students improve their physics study skills. These ideas were developed as part of Project IMPACTSEED (IMproving Physics And Chemistry Teaching in SEcondary Education), an outreach grant funded by the Alabama Commission on Higher Education. This project is motivated by a major pressing local need: A large number of high school physics teachers teach out of field. In the presentation, focus on topics such as the skills of how to develop long term memory, how to improve concentration power, how to take class notes, how to prepare for and take exams, how to study scientific subjects such as physics. We argue that the student who conscientiously uses the methods of efficient study habits will be able to achieve higher results than the student who does not; moreover, a student equipped with the proper study skills will spend much less time to learn a subject than a student who has no good study habits. The underlying issue here is not the quantity of time allocated to the study efforts by the student, but the efficiency and quality of actions. This work is supported by the Alabama Commission on Higher Education as part of IMPACTSEED grant.

  14. Avalanche effects near nanojunctions

    NASA Astrophysics Data System (ADS)

    Nandigana, Vishal V. R.; Aluru, N. R.

    2016-07-01

    In this article, we perform a computational investigation of a nanopore connected to external fluidic reservoirs of asymmetric geometries. The asymmetry between the reservoirs is achieved by changing the cross-sectional areas, and the reservoirs are designated as the micropore reservoir and macropore reservoir. When an electric field is applied, which is directed from the macropore towards the micropore reservoir, we observe local nonequilibrium chaotic current oscillations. The current oscillations originate at the micropore-nanopore interface owing to the local cascade of ions; we refer to this phenomenon as the "avalanche effects." We mathematically quantify chaos in terms of the maximum Lyapunov exponent. The maximum Lyapunov exponent exhibits a monotonic increase with the applied voltage and the macropore reservoir diameter. The temporal power spectra maps of the chaotic currents depict a low-frequency "1 /f "-type dynamics for the voltage chaos and "1 /f2 "-type dynamics for the macropore reservoir chaos. The results presented here offer avenues to manipulate ionic diodes and fluidic pumps.

  15. The alpha channeling effect

    SciTech Connect

    Fisch, N. J.

    2015-12-10

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  16. Effective family planning programs.

    PubMed

    Rosenfield, A G

    1973-01-01

    Organizational and content features of various national family planning programs are reviewed. The Thai program is cited as an example of a family planning program organized on a massive unipurpose compaign basis. The Korean and Taiwan programs have utilized special field workers while upgrading the general health care network. 3 major problems with family planning programs are: 1) the lack of experience with such programs; 2) lack of commitment at the highest political levels; and 3) medical conservatism. Utilization of all available contraceptive methods instead of reliance on 1 method would improve most programs. Nursing and auxiliary personnel could be trained to take over the work of physicians in family planning programs. This is already being done with IUD insertion and pill prescription in several programs. The postpartum tubal ligation approach has proven effective and should be extended. There is a place in all national programs for both the private and the commercial sectors. Incentives for clinics, personnel, and acceptors might spread family planning more rapidly. PMID:12309877

  17. Perceptual Repetition Blindness Effects

    NASA Technical Reports Server (NTRS)

    Hochhaus, Larry; Johnston, James C.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    The phenomenon of repetition blindness (RB) may reveal a new limitation on human perceptual processing. Recently, however, researchers have attributed RB to post-perceptual processes such as memory retrieval and/or reporting biases. The standard rapid serial visual presentation (RSVP) paradigm used in most RB studies is, indeed, open to such objections. Here we investigate RB using a "single-frame" paradigm introduced by Johnston and Hale (1984) in which memory demands are minimal. Subjects made only a single judgement about whether one masked target word was the same or different than a post-target probe. Confidence ratings permitted use of signal detection methods to assess sensitivity and bias effects. In the critical condition for RB a precue of the post-target word was provided prior to the target stimulus (identity precue), so that the required judgement amounted to whether the target did or did not repeat the precue word. In control treatments, the precue was either an unrelated word or a dummy.

  18. The photorefractive effect

    SciTech Connect

    Pepper, D.M. ); Kukhtarev, N.V. )

    1990-10-01

    When Arthur Ashkin and his colleagues at Bell Laboratories first noticed the photorefractive effect some 25 years ago, they considered the phenomenon a curiosity at best and a complete nuisance at worst. Today photorefractive materials are being shaped into components for a new generation of computers that exploit light instead of electricity. During the past 25 years investigators have discovered a wide variety of photorefractive materials, including insulators, semiconductors and organic compounds. Photorefractive materials, like film emulsions, change rapidly when exposed to bright light, respond slowly when subjected to dim light and capture sharp detail when struck by some intricate pattern of light. Unlike film, photorefractive materials are erasable: images can be stored or obliterated at whim or by design. By virtue of their sensitivity, robustness, and unique optical properties, photorefractive materials have the potential to be fashioned into data-processing elements for optical computers. In theory, these devices would allow optical computers to process information at much faster rates than their electronic counterparts. Employing photorefractive materials, workers have already developed the optical analogue to the transistor: if two laser beams interact within a photorefractive material, one beam can control, switch or amplify the second beam. Photorefractive materials also lie at the heart of devices that trace the edges of images, that connect networks of lasers and that store three-dimensional images.

  19. Multiphoton Effects in Rutile.

    NASA Astrophysics Data System (ADS)

    Royce, Gerald A.

    Multiphoton effects are investigated in crystalline rutile TiO(,2) using Nd:YAG laser photons. The 1.06 micron laser is operated in Q-switched mode with intensities up to 1.4 x 10('6) watts/cm('2) on the rutile crystal. Photoconductivity measurements provide data indicating a mixture of modes for electrons to be photoionized. Assuming aluminum impurity as the contributing sites, the first order photionization cross section is found to be 1.5 x 10('-26) cm('2) and second order cross section is found to be 7.7 x 10('-51) cm('4)-s. No appreciable change in cross section is observed for circular versus linear polarization of the laser. Observations of the photo-emission of the laser illuminated crystal provide radiative relaxation times on the order of 100 nanoseconds with emission peaks at 4500 and 5000 angstroms plus a near infrared continuum out to 1 micron. The thermoluminescence of rutile shows a number of trapping levels between 0.4 and 0.8 eV below the conduction band. These are attributed to an aluminum impurity.

  20. Effectively Rebutting Climate Misinformation

    NASA Astrophysics Data System (ADS)

    Cook, J.

    2011-12-01

    Climate science faces one of the best funded misinformation campaigns in history. The challenge for climate communicators is that misinformation is extremely difficult to dislodge, even after people understand that it's incorrect. Understanding how the human brain processes information is crucial to successful rebuttal. To avoid the danger of reinforcing misinformation (known as the 'backfire effect'), emphasis should be on positive facts, not the myth. Another key to dislodging myths is replacing them with an alternate narrative. In order to provide a narrative about arguments that misrepresent climate science, a broader understanding of how these arguments mislead is required. Movements that deny a scientific consensus have 5 characteristics in common and these also apply to climate denial. The arguments against the scientific consensus involve conspiracy theories, fake experts, cherry picking, logical fallacies and misrepresentation or impossible expectations. Learning to identify these rhetorical techniques is an important tool in the climate communication toolbox. I discuss examples of misrepresentations of climate science and the rhetorical techniques employed. I demonstrate how to respond to these arguments by explaining the facts of climate science while in the process, providing an alternate narrative.

  1. Avalanche effects near nanojunctions.

    PubMed

    Nandigana, Vishal V R; Aluru, N R

    2016-07-01

    In this article, we perform a computational investigation of a nanopore connected to external fluidic reservoirs of asymmetric geometries. The asymmetry between the reservoirs is achieved by changing the cross-sectional areas, and the reservoirs are designated as the micropore reservoir and macropore reservoir. When an electric field is applied, which is directed from the macropore towards the micropore reservoir, we observe local nonequilibrium chaotic current oscillations. The current oscillations originate at the micropore-nanopore interface owing to the local cascade of ions; we refer to this phenomenon as the "avalanche effects." We mathematically quantify chaos in terms of the maximum Lyapunov exponent. The maximum Lyapunov exponent exhibits a monotonic increase with the applied voltage and the macropore reservoir diameter. The temporal power spectra maps of the chaotic currents depict a low-frequency "1/f"-type dynamics for the voltage chaos and "1/f^{2}"-type dynamics for the macropore reservoir chaos. The results presented here offer avenues to manipulate ionic diodes and fluidic pumps. PMID:27575159

  2. [Effects of traumatic stress].

    PubMed

    Herbst, Gesa; Jaeger, Ulrich; Leichsenring, Falk; Streeck-Fischer, Annette

    2009-01-01

    The diagnosis PTSD does not adequately describe the impact of exposure to childhood trauma of the developing child. The objective of the study was to examine the prevalence of different interpersonal trauma types and to describe the long-term effects of maltreatment and neglect in a clinical sample of 34 adolescents. The majority (62%) of the sample was exposed to two different types of trauma during childhood. Emotional abuse and emotional neglect have been the most common trauma types (59%; 53%). 71% of the traumatized adolescents did not meet the criteria for PTSD. The most common diagnosis in the sample was Borderline Personality Disorder. All average scores at SCL-90-Symptom-Scale were clinical significant. Half of the sample reported suicide attempts and self destructive behavior. One third reported substance abuse and aggressive behavior against others respectively. None of the traumatized adolescents had a positive Self-concept. Altogether the results show that abused children and adolescents have a range of psychological sequelae that are not captured in the PTSD diagnostic criteria. Therefore the results support the necessity for a new and more precise diagnosis for chronically traumatized children and adolescents. PMID:19961125

  3. Harmful effects of nicotine

    PubMed Central

    Mishra, Aseem; Chaturvedi, Pankaj; Datta, Sourav; Sinukumar, Snita; Joshi, Poonam; Garg, Apurva

    2015-01-01

    With the advent of nicotine replacement therapy, the consumption of the nicotine is on the rise. Nicotine is considered to be a safer alternative of tobacco. The IARC monograph has not included nicotine as a carcinogen. However there are various studies which show otherwise. We undertook this review to specifically evaluate the effects of nicotine on the various organ systems. A computer aided search of the Medline and PubMed database was done using a combination of the keywords. All the animal and human studies investigating only the role of nicotine were included. Nicotine poses several health hazards. There is an increased risk of cardiovascular, respiratory, gastrointestinal disorders. There is decreased immune response and it also poses ill impacts on the reproductive health. It affects the cell proliferation, oxidative stress, apoptosis, DNA mutation by various mechanisms which leads to cancer. It also affects the tumor proliferation and metastasis and causes resistance to chemo and radio therapeutic agents. The use of nicotine needs regulation. The sale of nicotine should be under supervision of trained medical personnel. PMID:25810571

  4. Landslides - Cause and effect

    USGS Publications Warehouse

    Radbruch-Hall, D. H.; Varnes, D.J.

    1976-01-01

    Landslides can cause seismic disturbances; landslides can also result from seismic disturbances, and earthquake-induced slides have caused loss of life in many countries. Slides can cause disastrous flooding, particularly when landslide dams across streams are breached, and flooding may trigger slides. Slope movement in general is a major process of the geologic environment that places constraints on engineering development. In order to understand and foresee both the causes and effects of slope movement, studies must be made on a regional scale, at individual sites, and in the laboratory. Areal studies - some embracing entire countries - have shown that certain geologic conditions on slopes facilitate landsliding; these conditions include intensely sheared rocks; poorly consolidated, fine-grained clastic rocks; hard fractured rocks underlain by less resistant rocks; or loose accumulations of fine-grained surface debris. Field investigations as well as mathematical- and physical-model studies are increasing our understanding of the mechanism of slope movement in fractured rock, and assist in arriving at practical solutions to landslide problems related to all kinds of land development for human use. Progressive failure of slopes has been studied in both soil and rock mechanics. New procedures have been developed to evaluate earthquake response of embankments and slopes. The finite element method of analysis is being extensively used in the calculation of slope stability in rock broken by joints, faults, and other discontinuities. ?? 1976 International Association of Engineering Geology.

  5. (Limiting the greenhouse effect)

    SciTech Connect

    Rayner, S.

    1991-01-07

    Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.

  6. Snowplow Injection Front Effects

    NASA Technical Reports Server (NTRS)

    Moore, T. E.; Chandler, M. O.; Buzulukova, N.; Collinson, G. A.; Kepko, E. L.; Garcia-Sage, K. S.; Henderson, M. G.; Sitnov, M. I.

    2013-01-01

    As the Polar spacecraft apogee precessed through the magnetic equator in 2001, Polar encountered numerous substorm events in the region between geosynchronous orbit and 10 RE geocentric distance; most of them in the plasma sheet boundary layers. Of these, a small number was recorded near the neutral sheet in the evening sector. Polar/Thermal Ion Dynamics Experiment provides a unique perspective on the lowest-energy ion plasma, showing that these events exhibited a damped wavelike character, initiated by a burst of radially outward flow transverse to the local magnetic field at approximately 80 km/s. They then exhibit strongly damped cycles of inward/outward flow with a period of several minutes. After one or two cycles, they culminated in a hot plasma electron and ion injection, quite similar to those observed at geosynchronous orbit. Cold plasmaspheric plasmas comprise the outward flow cycles, while the inward flow cycles contain counterstreaming field-parallel polar wind-like flows. The observed wavelike structure, preceding the arrival of an earthward moving substorm injection front, suggests an outward displacement driven by the inward motion at local times closer to midnight, that is, a "snowplow" effect. The damped in/out flows are consistent with interchange oscillations driven by the arrival at the observed local time by an injection originating at greater radius and local time.

  7. Harmful effects of nicotine.

    PubMed

    Mishra, Aseem; Chaturvedi, Pankaj; Datta, Sourav; Sinukumar, Snita; Joshi, Poonam; Garg, Apurva

    2015-01-01

    With the advent of nicotine replacement therapy, the consumption of the nicotine is on the rise. Nicotine is considered to be a safer alternative of tobacco. The IARC monograph has not included nicotine as a carcinogen. However there are various studies which show otherwise. We undertook this review to specifically evaluate the effects of nicotine on the various organ systems. A computer aided search of the Medline and PubMed database was done using a combination of the keywords. All the animal and human studies investigating only the role of nicotine were included. Nicotine poses several health hazards. There is an increased risk of cardiovascular, respiratory, gastrointestinal disorders. There is decreased immune response and it also poses ill impacts on the reproductive health. It affects the cell proliferation, oxidative stress, apoptosis, DNA mutation by various mechanisms which leads to cancer. It also affects the tumor proliferation and metastasis and causes resistance to chemo and radio therapeutic agents. The use of nicotine needs regulation. The sale of nicotine should be under supervision of trained medical personnel. PMID:25810571

  8. Melatonin Anticancer Effects: Review

    PubMed Central

    Di Bella, Giuseppe; Mascia, Fabrizio; Gualano, Luciano; Di Bella, Luigi

    2013-01-01

    Melatonin (N-acetyl-5-methoxytryptamine, MLT), the main hormone produced by the pineal gland, not only regulates circadian rhythm, but also has antioxidant, anti-ageing and immunomodulatory properties. MLT plays an important role in blood composition, medullary dynamics, platelet genesis, vessel endothelia, and in platelet aggregation, leukocyte formula regulation and hemoglobin synthesis. Its significant atoxic, apoptotic, oncostatic, angiogenetic, differentiating and antiproliferative properties against all solid and liquid tumors have also been documented. Thanks, in fact, to its considerable functional versatility, MLT can exert both direct and indirect anticancer effects in factorial synergy with other differentiating, antiproliferative, immunomodulating and trophic molecules that form part of the anticancer treatment formulated by Luigi Di Bella (Di Bella Method, DBM: somatostatin, retinoids, ascorbic acid, vitamin D3, prolactin inhibitors, chondroitin-sulfate). The interaction between MLT and the DBM molecules counters the multiple processes that characterize the neoplastic phenotype (induction, promotion, progression and/or dissemination, tumoral mutation). All these particular characteristics suggest the use of MLT in oncological diseases. PMID:23348932

  9. The nemesis effect.

    PubMed

    Bright, C

    1999-01-01

    Environmental pressures are converging in ways that are likely to create a growing number of unanticipated crises. Two representative surprise crises involve the forests of Eastern North America and the coral reefs. These examples reveal 13 of the worst pressures inflicted on the planet and on mankind: climate change, acid rain, increasing ultraviolet light penetration, increasing tropospheric ozone levels, habitat loss, freshwater diversion, bioinvasion, alteration of fire cycles, persistent organic pollutants, nitrogen pollution, overfishing, population growth, and infectious diseases. It is noted that these crises will demand a fix, and each fix will require money, time, and political capital. However, ¿fixing¿ is not enough, since there is no realistic expectation of reducing the potential for additional crises. Hence, the best possible way of controlling such events is to do a better job of managing systems in their entirety. In view of this, several important principles are given; these include the following: 1) monoculture technologies are brittle; 2) direct opposition to a natural force usually invites failure or a form of success that is just as bad; 3) thinking through the likely systemic effects of a plan will help locate the risks, as well as indirect opportunities; 4) institutional pluralism can create a public space that no single institution could have created alone. PMID:12349644

  10. Psychological effects of stillbirth.

    PubMed

    Cacciatore, Joanne

    2013-04-01

    Despite the high prevalence globally, the death of a baby to stillbirth is an often misunderstood and disenfranchised loss. Mothers, fathers, and families struggle to cope with the immediate and long-lasting effects of a baby's death which can last for years and sometimes decades. In addition, providers can be adversely affected by stillbirth, particularly when met with experiential avoidance and a sense of guilt and failure. There is little evidence on intervention efficacy in acute grief following perinatal death; however, there is a growing body of scientific literature on the efficacy of mindfulness-based interventions in treating anxiety, depression, and other biopsychosocial maladies as well as improving patient satisfaction with psychosocial care. This paper explores one such intervention model, ATTEND (attunement, trust, therapeutic touch, egalitarianism, nuance, and death education), as a means to improve psychosocial care during both acute and chronic states of bereavement. Whereas the death of a baby to stillbirth is the ultimate paradox for providers and patients - the convergence of life and death and the fundamental contradiction it represents - with proper care and compassion, families stand a better chance in the face of such indescribable loss and they need not suffer alone. PMID:23040157

  11. A clear catalyst effect.

    PubMed

    Molitor, C

    1994-06-01

    A member of the International Council on Management of Population Programs (ICOMP) says that training women to manage and harbor employable skills has a very large multiplier effect. An international nongovernmental organization (NGO) based in Kuala Lumpur and established in 1973 to improve the performance of family planning programs in Asian developing countries through better management techniques, ICOMP boasts 35 developing countries as members. The organization's mandate has expanded over the years such that they now provide management and skills training programs through local NGOs in developing countries. The Asian Development Bank (ADB) has been assisting ICOMP's training programs in Bangladesh, Indonesia, Nepal, Pakistan, and the Philippines since 1989 with two technical assistance grants totalling $681,000. This is the first time that the Bank has supported training exclusively for women. Although the ADB planned to reach only 940 women under the first technical assistance, it eventually helped train more than 1200; an additional 1300 women have attended the courses offered under the Bank's second grant. Training courses are aimed at disadvantaged women who need training in employment skills, women engaged in community development or income-generating projects who need to develop basic management skills, and officials of the participating women NGOs who need training in organizing, developing, and implementing income-generating projects. The author discusses other elements of training aimed at improving the social and economic status of women, along with experiences of the Bangladesh Association for Community Education and the MELATI Foundation of Jakarta, Indonesia. PMID:12345682

  12. Neutron scattering from the Kondo Insulator SmB6

    NASA Astrophysics Data System (ADS)

    Broholm, Collin

    A review of neutron scattering work probing the Kondo insulator SmB6 is presented with special emphasis on assessing the topology of the underlying strongly renormalized band structure. A 14 meV excition dominates the spectrum and is evidence of strong electron correlations [1]. Though the data generally supports the proposal that SmB6 is a topological Kondo insulator, specific heat and high-resolution neutron scattering data show a continuum of states well below the bulk transport gap, which enrich the problem and may connect to the recent surprising de Haas van Alpen results. ``Interaction Driven Subgap Spin Exciton in the Kondo Insulator SmB6,'' W. T. Fuhrman, J. Leiner, P. Nikolic, G. E. Granroth, M. B. Stone, M. D. Lumsden, L. DeBeer-Schmitt, P. A. Alekseev, J.-M. Mignot, S. M. Koohpayeh, P. Cottingham, W. Adam Phelan, L. Schoop, T. M. McQueen, and C. Broholm, Phys. Rev. Lett. 114, 036401 (2015). Supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Material Sciences and Engineering, under Grant No. DEFG02-08ER46544 and the Gordon and Betty Moore Foundation.

  13. Effective sizes for subdivided populations

    SciTech Connect

    Chesser, R.K. Univ. of Georgia, Athens, GA ); Rhodes, O.E. Jr.; Sugg, D.W.; Schnabel, A. )

    1993-12-01

    Many derivations of effective population sizes have been suggested in the literature; however, few account for the breeding structure and none can readily be expanded to subdivided populations. Breeding structures influence gene correlations through their effects on the number of breeding individuals of each sex, the mean number of progeny per female, and the variance in the number of progeny produced by males and females. Additionally, hierarchical structuring in a population is determined by the number of breeding groups and the migration rates of males and females among such groups. This study derives analytical solutions for effective sizes that can be applied to subdivided populations. Parameters that encapsulate breeding structure and subdivision are utilized to derive the traditional inbreeding and variance effective sizes. Also, it is shown that effective sizes can be determined for any hierarchical level of population structure for which gene correlations can accrue. Derivations of effective sizes for the accumulation of gene correlations within breeding groups (coancestral effective size) and among breeding groups (intergroup effective size) are given. The results converge to traditional single population measures when similar assumptions are applied. In particular, inbreeding and intergroup effective sizes are shown to be special cases of the coancestral effective size, and intergroup and variance effective sizes will be equal if the population census remains constant. Instantaneous solutions for effective size, at any time after gene correlation begins to accrue, are given in terms of traditional F statistics or transition equations. All effective sizes are shown to converge upon a common asymptotic value when breeding tactics and migration rates are constant. The asymptotic effective size can be expressed in terms of the fixation indices and the number of breeding groups; however, the rate of approach to the asymptote is dependent upon dispersal rates.

  14. Neuroendocrine effects of light

    NASA Astrophysics Data System (ADS)

    Reiter, Russel J.

    1991-09-01

    The light/dark cycle to which animals, and possibly humans, are exposed has a major impact on their physiology. The mechanisms whereby specific tissues respond to the light/dark cycle involve the pineal hormone melatonin. The pineal gland, an end organ of the visual system in mammals, produces the hormone melatonin only at night, at which time it is released into the blood. The duration of elevated nightly melatonin provides every tissue with information about the time of day and time of year (in animals that are kept under naturally changing photoperiods). Besides its release in a circadian mode, melatonin is also discharged in a pulsatile manner; the physiological significance, if any, of pulsatile melatonin release remains unknown. The exposure of animals including man to light at night rapidly depresses pineal melatonin synthesis and, therefore, blood melatonin levels drop precipitously. The brightness of light at night required to depress melatonin production is highly species specific. In general, the pineal gland of nocturnally active mammals, which possess rod-dominated retinas, is more sensitive to inhibition by light than is the pineal gland of diurnally active animals (with cone-dominated retinas). Because of the ability of the light/dark cycle to determine melatonin production, the photoperiod is capable of influencing the function of a variety of endocrine and non-endocrine organs. Indeed, melatonin is a ubiquitously acting pineal hormone with its effects on the neuroendocrine system having been most thoroughly investigated. Thus, in nonhuman photoperiodic mammals melatonin regulates seasonal reproduction; in humans also, the indole has been implicated in the control of reproductive physiology.

  15. Models for effective prevention.

    PubMed

    Perry, C L; Kelder, S H

    1992-07-01

    The social influence models do provide some optimism for primary prevention efforts. Prevention programs appear most effective when 1) the target behavior of the intervention has received increasing societal disapproval (such as cigarette smoking), 2) multiple years of behavioral health education are planned, and 3) community-wide involvement or mass media complement a school-based peer-led program (45,46). Short-term programs and those involving alcohol use have had less favorable outcomes. Future research in primary prevention should address concerns of high-risk groups and high-risk countries, such as lower income populations in the United States or countries that have large adolescent homeless populations. The utilization of adolescent leaders for program dissemination might be particularly critical in these settings. A second major and global concern should focus upon alcohol use and alcohol-related problems. In many communities adolescent alcohol use is normative and even adult supported. Thus, young people are getting quite inconsistent messages on alcohol from their schools, from TV, from peers, and from parents. This inconsistency may translate into many tragic and avoidable deaths for young people. Clearly, in the area of alcohol-related problems, community-wide involvement may be necessary. A third direction for prevention research should involve issues of norms, access, and enforcement including policy interventions, such as involve the availability of cigarette vending machines or the ease of under-age buying or levels of taxation. These methods affect adolescents more acutely since their financial resources, for the most part, are more limited. These policy level methods also signify to adolescents what adults consider appropriate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1390786

  16. [Longterm effects of steroid therapy].

    PubMed

    Kuna, P

    1998-01-01

    Asthma is a chronic inflammatory disease of the airways play. Anti-inflammatory drugs the fundamental role in the treatment of asthma and among them steroids are the most important. However, oral steroids may cause many serious side effects. A major breakthrough in the treatment of asthma was introducing inhaled steroids. Inhaled steroids have much less side effects than oral steroids, although they have the same anti-inflammatory activity. Long term effect of inhaled steroids can be divided into wanted and unwanted outcome. The desirable anti-inflammatory effect of steroids is reflected by lowering of bronchial hyperresponsiveness and a better control of asthma symptoms. Inhaled corticosteroid may have systemic side effects similar to those observed with oral steroids such as 1) adrenal suppression, 2) effect on bone metabolism, 3) growth suppression in children, 4) impaired skin collagen synthesis, 5) cataract, 6) metabolic disturbances, 7) effect on central nervous system. Topical side effects of inhaled corticosteroid such as oral candidiasis, dysphonia and cough effect about 10 to 30% of patients taking those drugs. Summing up it is advisable to use inhaled corticosteroid in the lower effective dose. PMID:9610231

  17. Radiation Effects: Core Project

    NASA Technical Reports Server (NTRS)

    Dicello, John F.

    1999-01-01

    The risks to personnel in space from the naturally occurring radiations are generally considered to be one of the most serious limitations to human space missions, as noted in two recent reports of the National Research Council/National Academy of Sciences. The Core Project of the Radiation Effects Team for the National Space Biomedical Research Institute is the consequences of radiations in space in order to develop countermeasure, both physical and pharmaceutical, to reduce the risks of cancer and other diseases associated with such exposures. During interplanetary missions, personnel in space will be exposed to galactic cosmic rays, including high-energy protons and energetic ions with atomic masses of iron or higher. In addition, solar events will produce radiation fields of high intensity for short but irregular durations. The level of intensity of these radiations is considerably higher than that on Earth's surface, and the biological risks to astronauts is consequently increased, including increased risks of carcinogenesis and other diseases. This group is examining the risk of cancers resulting from low-dose, low-dose rate exposures of model systems to photons, protons, and iron by using ground-based accelerators which are capable of producing beams of protons, iron, and other heavy ions at energies comparable to those encountered in space. They have begun the first series of experiments using a 1-GeV iron beam at the Brookhaven National Laboratory and 250-MeV protons at Loma Linda University Medical Center's proton synchrotron facility. As part of these studies, this group will be investigating the potential for the pharmaceutical, Tamoxifen, to reduce the risk of breast cancer in astronauts exposed to the level of doses and particle types expected in space. Theoretical studies are being carried out in a collaboration between scientists at NASA's Johnson Space Center and Johns Hopkins University in parallel with the experimental program have provided

  18. Magnetocaloric effect in manganites

    SciTech Connect

    Koroleva, L. I. Zashchirinskii, D. M.; Morozov, A. S.; Szymczak, R.

    2012-10-15

    The magnetocaloric effect (MCE) in La{sub 1-x}Sr{sub x}MnO{sub 3}, Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3}, and PrBaMn{sub 2}O{sub 6} compounds is studied. The maximum values of MCE ({Delta}T{sub max}) determined by a direct method in the second and third compositions and in La{sub 0.9}Sr{sub 0.1}MnO{sub 3} are found to be much lower than those calculated from the change of the magnetic part of entropy in the Curie temperature (T{sub C}) and the Neel temperature (T{sub N}) range. The negative contribution of the antiferromagnetic (AFM) part of a sample in the La{sub 1-x}Sr{sub x}MnO{sub 3} system at 0.1 {<=} x {<=} 0.3 decreases {Delta}T{sub max} and changes the {Delta}T(T) curve shape, shifting its maximum 20-40 K above T{sub C}. Lower values of {Delta}T{sub max} are detected in the range T{sub C} = 130-142 K in polycrystalline and single-crystal Sm{sub 0.55}Sr{sub 0.45}MnO{sub 3} samples cooled in air. If such samples were cooled in an oxygen atmosphere (which restores broken Mn-O-Mn bonds and, thus, increases the volume of CE-type AFM clusters), the maximum in the temperature dependence of MCE is located at T{sub N} (243 K) for CE-type AFM clusters. A magnetic field applied to a sample during the MCE measurements transforms these clusters into a ferromagnetic (FM) state, and both types of clusters decompose at T = T{sub N}. The PrBaMn{sub 2}O{sub 6} composition undergoes an AFM-FM transition at 231 K, and the temperature dependence of its MCE has a sharp minimum at T = 234 K, where MCE is negative, and a broad maximum covering T{sub C}. The absolute values of MCE at both extrema are several times lower than those calculated from the change in the magnetic entropy. These phenomena are explained by the presence of a magnetically heterogeneous FM-AFM state in these manganites.

  19. The wow effect

    NASA Astrophysics Data System (ADS)

    Biondi, Riccardo; Pagnotta, Paola; Trentini, Gabriella; Cirotti, Tiziana; Parrettini, Cinzia

    2015-04-01

    Teaching science at elementary school is a hard work for scientists since we usually use to talk to colleagues by using technical and specific words not understandable by general public and school students. Finding plain language for explaining what is the research and for describing scientific topics was the objective of this work. In collaboration with the school teachers, I organized a series of meetings describing the same subject with different approaches and, at the end of the test-period, we did a survey within the 60 students (10-11 years old) for understanding which was the most attractive approach for them. The survey asked to the students the 3 topics (which could be a sentence, an activity or simply a picture) that they remember at most from all the meetings. Later on we asked why they have chosen those topics. The common topic was atmospheric and space science and it was approached by using, books, videos, frontal lectures with the support of pictures and other material, and with direct hands-on lab such as 3D puzzles for building a satellite. Nobody highlights having read a book. The majority of the students (male and female) really appreciated having built their own satellite (wow, I have done it!) and how's the life into the International Space Station (wow, everything flies there and they drink the pee!). Many female students were fascinated by the stars and by the Italian astronaut Samantha Cristoforetti (wow, an Italian woman is there!) while many boys were attracted by the technology evolution (wow, how a mobile phone could be that big?!). Surprisingly 3 students remember a quick (showed for just a few seconds) and blurred picture showing the glory effect by aircraft (wow, a circular rainbow!). The survey shows how the students mostly appreciate the hands-on labs and being active and creative, their attention decreases but it is still active with frontal lectures or videos showing them real examples or something impacting their day-life.

  20. Effects in skeletal muscle.

    PubMed

    Young, Andrew

    2005-01-01

    was reported to not affect muscle glucose transport. In most of the above respects, amylin behaved similarly to catecholamines in skeletal muscle. The pharmacology of amylin's effects on muscle glycogen metabolism was consistent with a classic amylin pharmacology in whole animals and in isolated soleus muscle. In one cell line, the pharmacology was CGRPergic. Amylin, like insulin, stimulated Na+/K+ ATPase activity and enhanced muscle contractility in vitro. PMID:16492548

  1. Effective sizes for subdivided populations.

    PubMed

    Chesser, R K; Rhodes, O E; Sugg, D W; Schnabel, A

    1993-12-01

    Many derivations of effective population sizes have been suggested in the literature; however, few account for the breeding structure and none can readily be expanded to subdivided populations. Breeding structures influence gene correlations through their effects on the number of breeding individuals of each sex, the mean number of progeny per female, and the variance in the number of progeny produced by males and females. Additionally, hierarchical structuring in a population is determined by the number of breeding groups and the migration rates of males and females among such groups. This study derives analytical solutions for effective sizes that can be applied to subdivided populations. Parameters that encapsulate breeding structure and subdivision are utilized to derive the traditional inbreeding and variance effective sizes. Also, it is shown that effective sizes can be determined for any hierarchical level of population structure for which gene correlations can accrue. Derivations of effective sizes for the accumulation of gene correlations within breeding groups (coancestral effective size) and among breeding groups (intergroup effective size) are given. The results converge to traditional, single population measures when similar assumptions are applied. In particular, inbreeding and intergroup effective sizes are shown to be special cases of the coancestral effective size, and intergroup and variance effective sizes will be equal if the population census remains constant. Instantaneous solutions for effective sizes, at any time after gene correlation begins to accrue, are given in terms of traditional F statistics or transition equations. All effective sizes are shown to converge upon a common asymptotic value when breeding tactics and migration rates are constant. The asymptotic effective size can be expressed in terms of the fixation indices and the number of breeding groups; however, the rate of approach to the asymptote is dependent upon dispersal

  2. Effects of sea spray geoengineering

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-03-01

    Anthropogenic climate warming is leading to consideration of options for geoengineering to offset rising carbon dioxide levels. One potential technique involves injecting artificial sea spray into the atmosphere. The sea salt particles would affect Earth's radiation budget directly, by scattering incoming solar radiation, and indirectly, by acting as cloud condensation nuclei, which could lead to whiter clouds that reflect more radiation. However, the potential effects of this method, especially the direct effects, are not fully known. Partanen et al. studied the effects of artificial sea spray using climate model simulations. They found that outside of the most heavily clouded regions the direct effect of scattering of radiation was an important part of the total effect. They also examined the effect of particle size and found that decreasing the size of injected particles could improve the efficiency of the geoengineering technique.

  3. Biological Effects of Ionizing Radiation

    DOE R&D Accomplishments Database

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  4. The Thirring-Lense Effect

    NASA Astrophysics Data System (ADS)

    Embacher, Franz

    The Thirring-Lense effect is the phenomenon that an observer near a rotating mass, being in a state which is non-rotating with respect to the rest of the universe, experiences extra inertial forces, i.e. becomes dizzy. The first anticipation of the effect goes back to Ernst Mach; its first quantitative prediction on the basis of general relativity was given by Hans Thirring and Joseph Lense. Almost ninety years later, the effect seems to be experimentally verified.

  5. Twisted mass finite volume effects

    SciTech Connect

    Colangelo, Gilberto; Wenger, Urs; Wu, Jackson M. S.

    2010-08-01

    We calculate finite-volume effects on the pion masses and decay constant in twisted mass lattice QCD at finite lattice spacing. We show that the lighter neutral pion in twisted mass lattice QCD gives rise to finite-volume effects that are exponentially enhanced when compared to those arising from the heavier charged pions. We demonstrate that the recent two flavor twisted mass lattice data can be better fitted when twisted mass effects in finite-volume corrections are taken into account.

  6. [Adverse ocular effects of vaccinations].

    PubMed

    Ness, T; Hengel, H

    2016-07-01

    Vaccinations are very effective measures for prevention of infections but are also associated with a long list of possible side effects. Adverse ocular effects following vaccination have been rarely reported or considered to be related to vaccinations. Conjunctivitis is a frequent sequel of various vaccinations. Oculorespiratory syndrome and serum sickness syndrome are considered to be related to influenza vaccinations. The risk of reactivation or initiation of autoimmune diseases (e. g. uveitis) cannot be excluded but has not yet been proven. Overall the benefit of vaccination outweighs the possible but very low risk of ocular side effects. PMID:27357302

  7. Side effects with amiodarone therapy.

    PubMed Central

    Shukla, R.; Jowett, N. I.; Thompson, D. R.; Pohl, J. E.

    1994-01-01

    Amiodarone hydrochloride is increasingly being used in the treatment of ventricular and supraventricular arrhythmias. Although a highly effective anti-arrhythmic agent, its use is restricted by the high incidence of side effects. To elucidate the value of monitoring serum level of both the parent drug and its active metabolite in predicting the occurrence of side effects, the investigators examined 109 patients from a register of patients treated with amiodarone for the prevalence of known side effects of the drug. The register contained over 90% of patients treated with amiodarone at the Leicester General Hospital during the period of the study. The findings suggest cutaneous side effects and abnormal thyroid function tests (without overt gland dysfunction) are more likely to occur with increasing duration of treatment and cumulative dosage. However, neither the serum amiodarone level nor the serum metabolite level had any predictive power for the occurrence of side effects. In view of this finding, it is recommended that close attention be paid to the continued clinical monitoring of side effects and that there is utility in measuring the serum amiodarone level in each patient to avoid the prescription of unnecessarily high doses. This is necessary not only to lessen the occurrence of cumulative dose-related side effects, but also because the variable but very long half-life of the drug leads to difficulties in relating spot drug levels to long-term effects. PMID:7937427

  8. The structure of sequential effects.

    PubMed

    Gökaydin, Dinis; Navarro, Daniel J; Ma-Wyatt, Anna; Perfors, Amy

    2016-01-01

    There is a long history of research into sequential effects, extending more than one hundred years. The pattern of sequential effects varies widely with both experimental conditions as well as for different individuals performing the same experiment. Yet this great diversity of results is poorly understood, particularly with respect to individual variation, which save for some passing mentions has largely gone unreported in the literature. Here we seek to understand the way in which sequential effects vary by identifying the causes underlying the differences observed in sequential effects. In order to achieve this goal we perform principal component analysis on a dataset of 158 individual results from participants performing different experiments with the aim of identifying hidden variables responsible for sequential effects. We find a latent structure consisting of 3 components related to sequential effects-2 main and 1 minor. A relationship between the 2 main components and the separate processing of stimuli and of responses is proposed on the basis of previous empirical evidence. It is further speculated that the minor component of sequential effects arises as the consequence of processing delays. Independently of the explanation for the latent variables encountered, this work provides a unified descriptive model for a wide range of different types of sequential effects previously identified in the literature. In addition to explaining individual differences themselves, it is demonstrated how the latent structure uncovered here is useful in understanding the classical problem of the dependence of sequential effects on the interval between successive stimuli. PMID:26523425

  9. Modelling of the YORP effect

    NASA Astrophysics Data System (ADS)

    Golubov, O.

    2015-10-01

    In the talk I will review the recent advances in the theoretical understanding of the YORP effect. I describe the standard mathematical formalism used for the YORP effect, with the special focus on the limitations of the standard theory and its possible genaralizations. I discuss the sensitivity of the YORP effect to small-scale structures and the novel concept of the tangential YORP, a torque that alters even the rotation of symmetric asteroids due to uneven heat conductivity in small stones composing the surface. Finally, I consider the overall evolution of an asteroid experiencing the YORP effect.

  10. Partial order of quantum effects

    NASA Astrophysics Data System (ADS)

    Lahti, Pekka J.; Ma̧czynski, Maciej J.

    1995-04-01

    The set of effects is not a lattice with respect to its natural order. Projection operators do have the greatest lower bounds (and the least upper bounds) in that set, but there are also other (incomparable) effects which share this property. However, the coexistence, the commutativity, and the regularity of a pair of effects are not sufficient for the existence of their infima and suprema. The structure of the range of an observable (as a normalized POV measure) can vary from that of a commutative Boolean to a noncommutative non-Boolean subset of effects.

  11. EFFECTIVE POROSITY IMPLIES EFFECTIVE BULK DENSITY IN SORBING SOLUTE TRANSPORT

    SciTech Connect

    Flach, G.

    2012-02-27

    The concept of an effective porosity is widely used in solute transport modeling to account for the presence of a fraction of the medium that effectively does not influence solute migration, apart from taking up space. This non-participating volume or ineffective porosity plays the same role as the gas phase in single-phase liquid unsaturated transport: it increases pore velocity, which is useful towards reproducing observed solute travel times. The prevalent use of the effective porosity concept is reflected by its prominent inclusion in popular texts, e.g., de Marsily (1986), Fetter (1988, 1993) and Zheng and Bennett (2002). The purpose of this commentary is to point out that proper application of the concept for sorbing solutes requires more than simply reducing porosity while leaving other material properties unchanged. More specifically, effective porosity implies the corresponding need for an effective bulk density in a conventional single-porosity model. The reason is that the designated non-participating volume is composed of both solid and fluid phases, both of which must be neglected for consistency. Said another way, if solute does not enter the ineffective porosity then it also cannot contact the adjoining solid. Conceptually neglecting the fluid portion of the non-participating volume leads to a lower (effective) porosity. Likewise, discarding the solid portion of the non-participating volume inherently leads to a lower or effective bulk density. In the author's experience, practitioners virtually never adjust bulk density when adopting the effective porosity approach.

  12. Effective Leadership for Effective Schools: A Survey of Principal Attitudes.

    ERIC Educational Resources Information Center

    Arnn, John W., Jr.; Mangieri, John N.

    1988-01-01

    Effective principals agree on what should be occurring in the classrooms in their schools, according to investigators who queried principals in 202 schools identified as "effective." The most important characteristic of teachers, they responded, is to be task-oriented. (CJH)

  13. TOLUENE DOSE-EFFECT META ANALYSIS AND IMPORTANCE OF EFFECTS

    EPA Science Inventory

    TOLUENE DOSE-EFFECT META ANALYSES AND IMPORTANCE OF EFFECTS
    Benignus, V.A., Research Psychologist, ORD, NHEERL, Human Studies Division,
    919-966-6242, benignus.vernon@epa.gov
    Boyes, W.K., Supervisory Health Scientist, ORD, NHEERL, Neurotoxicology Division
    919-541-...

  14. The Estimated Effects of Service Learning on Students' Intercultural Effectiveness

    ERIC Educational Resources Information Center

    Kilgo, Cindy A.

    2015-01-01

    As the higher education landscape continues to diversify, intercultural effectiveness comes to the forefront among important outcomes for students. Service learning is one programmatic tool that institutions of higher education can use to foster the development of intercultural effectiveness. This study provides evidence that service learning is…

  15. Effects beyond Effectiveness: Teaching as a Performative Act

    ERIC Educational Resources Information Center

    Liew, Warren Mark

    2013-01-01

    This article develops the familiar metaphor of teaching as performance towards a definition of "teaching as performative act," where words and actions aim to effect cognitive, affective, and behavioral changes in learners. To what extent, however, are the consequences of pedagogical actions commensurate with their intended effects? Can a science…

  16. The Worked Example Effect, the Generation Effect, and Element Interactivity

    ERIC Educational Resources Information Center

    Chen, Ouhao; Kalyuga, Slava; Sweller, John

    2015-01-01

    The worked example effect indicates that examples providing full guidance on how to solve a problem result in better test performance than a problem-solving condition with no guidance. The generation effect occurs when learners generating responses demonstrate better test performance than learners in a presentation condition that provides an…

  17. A side effect resource to capture phenotypic effects of drugs

    PubMed Central

    Kuhn, Michael; Campillos, Monica; Letunic, Ivica; Jensen, Lars Juhl; Bork, Peer

    2010-01-01

    The molecular understanding of phenotypes caused by drugs in humans is essential for elucidating mechanisms of action and for developing personalized medicines. Side effects of drugs (also known as adverse drug reactions) are an important source of human phenotypic information, but so far research on this topic has been hampered by insufficient accessibility of data. Consequently, we have developed a public, computer-readable side effect resource (SIDER) that connects 888 drugs to 1450 side effect terms. It contains information on frequency in patients for one-third of the drug–side effect pairs. For 199 drugs, the side effect frequency of placebo administration could also be extracted. We illustrate the potential of SIDER with a number of analyses. The resource is freely available for academic research at http://sideeffects.embl.de. PMID:20087340

  18. Effects of Small Oscillations on the Effective Area

    SciTech Connect

    Cotroneo, V.; Conconi, P.; Pareschi, G.; Spiga, D.; Tagliaferri, G.

    2009-05-11

    We analyze the effective area of the Simbol-X mirrors as a function of the off-axis angle for small oscillations. A reduction is expected due to: 1) geometrical effects, because some of the photons miss the secondary mirror surface; 2) reflectivity effects, caused by the variation of the coating reflectivity with the incidence angle. The former are related to the length of the two mirror surfaces, and can be reduced by making the secondary mirror longer. The second ones are energy-dependent, and strongly related to the characteristics of the reflecting coating. These effects are analyzed by means of ray-tracing simulations in order to optimize the mirror and coating design, aiming to improve the effective area stability.

  19. Effect of orientation anisotropy on calculating effective electrical conductivities

    NASA Astrophysics Data System (ADS)

    Myles, Timothy D.; Peracchio, Aldo A.; Chiu, Wilson K. S.

    2014-05-01

    This paper develops an analytical effective medium theory (EMT) equation for calculating the effective conductivity of a mixture based on Maxwell's and Maxwell-Garnett's theories, extended to higher volume fractions using Bruggeman's unsymmetrical treatment (BUT), with a long term goal of extending the treatment to mixtures more representative of real materials in order to calculate their effective electrical conductivity. The development accounts for spheroid shaped inclusions of varying degrees of anisotropic orientation. The orientation is described by the introduction of a distribution function. Two methodologies valid for the inclusion dilute limit were used to evaluate the effective conductivity: one based on Maxwell's far field approach, and the other based on the Maxwell-Garnett in the matrix approach. It was found that while the dilute limit equations for the effective conductivity were different, the final EMT equations derived by applying BUT collapsed to the same formula which was generalized for anisotropic orientation based on the distribution function presented.

  20. What Is Effectiveness? Panel Discussion.

    ERIC Educational Resources Information Center

    Zigmond, Naomi

    Two papers are presented from a panel discussion moderated by Naomi Zigmond, who introduces the papers with a note on definitions and measures of intervention effectiveness. "Some Thoughts on Effective Intervention for Handicapped Preschoolers," by Phillip Strain, notes that special education researchers attempt to be efficient, economical,…

  1. The Effectiveness of Early Intervention.

    ERIC Educational Resources Information Center

    Guralnick, Michael J., Ed.

    This book reviews research on the effectiveness of early intervention for children with disabilities or who are at risk. Program factors for children at risk and with disabilities, the effects of early intervention on different types of disabilities, and the outcomes of early intervention are explored. Chapters include: "Second-Generation Research…

  2. Evolution of maternal effect senescence

    PubMed Central

    Moorad, Jacob A.; Nussey, Daniel H.

    2016-01-01

    Increased maternal age at reproduction is often associated with decreased offspring performance in numerous species of plants and animals (including humans). Current evolutionary theory considers such maternal effect senescence as part of a unified process of reproductive senescence, which is under identical age-specific selective pressures to fertility. We offer a novel theoretical perspective by combining William Hamilton’s evolutionary model for aging with a quantitative genetic model of indirect genetic effects. We demonstrate that fertility and maternal effect senescence are likely to experience different patterns of age-specific selection and thus can evolve to take divergent forms. Applied to neonatal survival, we find that selection for maternal effects is the product of age-specific fertility and Hamilton’s age-specific force of selection for fertility. Population genetic models show that senescence for these maternal effects can evolve in the absence of reproductive or actuarial senescence; this implies that maternal effect aging is a fundamentally distinct demographic manifestation of the evolution of aging. However, brief periods of increasingly beneficial maternal effects can evolve when fertility increases with age faster than cumulative survival declines. This is most likely to occur early in life. Our integration of theory provides a general framework with which to model, measure, and compare the evolutionary determinants of the social manifestations of aging. Extension of our maternal effects model to other ecological and social contexts could provide important insights into the drivers of the astonishing diversity of lifespans and aging patterns observed among species. PMID:26715745

  3. How Principals Support Teacher Effectiveness

    ERIC Educational Resources Information Center

    Gallagher, Michael

    2012-01-01

    The current standards and accountability regime describes effective teaching as the ability to increase student achievement on standardized tests. This narrow definition of effectiveness can lead principals to create school cultures myopically focused on student achievement data. A "laser-like focus on academic achievement," if employed too…

  4. Superconducting Field-Effect Transistors

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul; Romanofsky, Robert R.; Tabib-Azar, Massood

    1995-01-01

    Devices offer switching speeds greater than semiconducting counterparts. High-Tc superconducting field-effect transistors (SUPEFETs) investigated for use as electronic switches in delay-line-type microwave phase shifters. Resemble semiconductor field-effect transistors in some respects, but their operation based on different principle; namely, electric-field control of transition between superconductivity and normal conductivity.

  5. Memory Processes in Media Effects.

    ERIC Educational Resources Information Center

    Kellermann, Kathy

    1985-01-01

    Explores the role of memory in mediating mass communication effects. Examines (1) the nature of memory, (2) issues in retention and recall of media messages, (3) methods of promoting retention and recall of media messages, and (4) implications of memory processes for mass media effects. (PD)

  6. Effective Evaluation through Appreciative Inquiry

    ERIC Educational Resources Information Center

    Dunlap, Cheryl A.

    2008-01-01

    Evaluators in the HPI field can improve their performance program results with effective evaluation through appreciative inquiry. Appreciative inquiry and evaluation have many similarities, and when combined they add value and effectiveness to the measurement of intervention results. Appreciative inquiry is beneficial in many evaluation contexts:…

  7. Tritrophic Effects in Bt Cotton

    ERIC Educational Resources Information Center

    Gutierrez, Andrew Paul

    2005-01-01

    Transgenic insecticidal Bt crops are being increasingly used worldwide, and concern is increasing about resistance and their effects on nontarget organisms. The toxin acts as a weak pesticide and, hence, the effects are subtler than those of chemical biocides. However, the toxin is ever present, but concentrations vary with age of plant and plant…

  8. Age Effects in Information Processing.

    ERIC Educational Resources Information Center

    Furukawa, James M.; And Others

    Attempts to modify or ameliorate the effects of declining cognitive abilities of the elderly have met with limited success. To focus on the effects of age in cognitive processing capacity (CPC), Furukawa's (1977) CPC test was administered individually to 3 age groups (16-30, 31-45, and 45-60) of 15 subjects each. Speed of processing old and new…

  9. Importance of Effective Listening Infomercial

    ERIC Educational Resources Information Center

    Johnson-Curiskis, Nanette

    2009-01-01

    This article details an activity intended for use in a course with a unit on effective listening, including listening courses, public speaking, and interpersonal communication. Students will explain the importance of effective and active listening for a target audience by producing an infomercial for a product or service which they design.

  10. Space environment effects (M0006)

    NASA Technical Reports Server (NTRS)

    Angelo, J. A., Jr.; Madonna, R. G.; Altadonna, L. P.; Dagostino, M. D.; Chang, J. Y.; Alfano, R. R.; Caplan, V. L.

    1984-01-01

    The effects of long term exposure to the near Earth space environment on advanced electrooptical and radiation sensor components were examined. The effect of long duration spaceflight on the germination rate of selected terrestrial plant seeds is observed in exobiological experiments.

  11. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-08-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  12. Octupole correlation effects in nuclei

    SciTech Connect

    Chasman, R.R.

    1992-01-01

    Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

  13. Teacher Evaluation: Archiving Teaching Effectiveness

    ERIC Educational Resources Information Center

    Nielsen, Lance D.

    2014-01-01

    Teacher evaluation is a current hot topic within music education. This article offers strategies for K-12 music educators on how to promote their effectiveness as teachers through archival documentation in a teacher portfolio. Using the Danielson evaluation model (based on four domains of effective teaching practices), examples of music teaching…

  14. [Between Werther and Papageno effects].

    PubMed

    Scherr, S; Steinleitner, A

    2015-05-01

    Research on the impact of suicide depictions in the media is traditionally focussed on two possible outcomes: on the one hand, there is ample evidence for additional copycat effects after media coverage of suicides referred to as the Werther effect but on the other hand, suicide rates decrease after appropriate media depictions of suicides referred to as the Papageno effect. It is still uncertain what exactly qualifies studies that only limitedly support an imitative or preventive media effect, i.e. studies with ambiguous findings, as they are often disregarded. The present literature review focuses on equivocal studies (n = 25) on copycat suicides that were systematically analyzed based on theoretically derived criteria. The results of the systematic analysis of all identified studies imply that media effects on suicidality are better understood and discussed as a continuum between the two extremes that were introduced as either a damaging Werther effect or a beneficial Papageno effect. Future studies must clarify what factors contribute to a shift from ambiguous findings to harmful media effects on individual suicidality. PMID:25700723

  15. Effective Schools: Mirror or Mirage?

    ERIC Educational Resources Information Center

    Tomlinson, Tommy M.

    1981-01-01

    Identifies and analyzes characteristics which are frequently mentioned as contributing to effective schools. Among the characteristics are that they improve the effectiveness and efficiency of students' work by organizing material and/or instruction, increase the amount of work students perform per unit of time, reduce distractions, and encourage…

  16. Measuring the Effects of Schooling.

    ERIC Educational Resources Information Center

    Hattie, John

    1992-01-01

    A simple statistical model to measure the effects of innovation and schooling is proposed. Synthesis of 134 meta-analyses revealed that educational innovations can be expected to change average achievement by 0.4 standards deviations and affective outcomes by 0.2 standard deviations. Innovation and feedback appear to enhance effects;…

  17. Effective Vocal Production in Performance.

    ERIC Educational Resources Information Center

    King, Robert G.

    If speech instructors are to teach students to recreate for an audience an author's intellectual and emotional meanings, they must teach them to use human voice effectively. Seven essential elements of effective vocal production that often pose problems for oral interpretation students should be central to any speech training program: (1)…

  18. Evolution of maternal effect senescence.

    PubMed

    Moorad, Jacob A; Nussey, Daniel H

    2016-01-12

    Increased maternal age at reproduction is often associated with decreased offspring performance in numerous species of plants and animals (including humans). Current evolutionary theory considers such maternal effect senescence as part of a unified process of reproductive senescence, which is under identical age-specific selective pressures to fertility. We offer a novel theoretical perspective by combining William Hamilton's evolutionary model for aging with a quantitative genetic model of indirect genetic effects. We demonstrate that fertility and maternal effect senescence are likely to experience different patterns of age-specific selection and thus can evolve to take divergent forms. Applied to neonatal survival, we find that selection for maternal effects is the product of age-specific fertility and Hamilton's age-specific force of selection for fertility. Population genetic models show that senescence for these maternal effects can evolve in the absence of reproductive or actuarial senescence; this implies that maternal effect aging is a fundamentally distinct demographic manifestation of the evolution of aging. However, brief periods of increasingly beneficial maternal effects can evolve when fertility increases with age faster than cumulative survival declines. This is most likely to occur early in life. Our integration of theory provides a general framework with which to model, measure, and compare the evolutionary determinants of the social manifestations of aging. Extension of our maternal effects model to other ecological and social contexts could provide important insights into the drivers of the astonishing diversity of lifespans and aging patterns observed among species. PMID:26715745

  19. Teaching the Photoelectric Effect Inductively

    ERIC Educational Resources Information Center

    Sokolowski, Andrzej

    2013-01-01

    Research has shown that students have difficulty understanding the underlying process of the photoelectric effect. Thus, this study sought to utilize an inductively situated lesson for teaching the photoelectric effect, hypothesizing that this type of enquiry would help learners delve deeper into the principles of the phenomenon and provide a…

  20. School Effectiveness and Principal Productivity.

    ERIC Educational Resources Information Center

    Fredericks, Janet; Brown, Steven

    1993-01-01

    Measuring the school administrator's productivity based on the existence of effective school characteristics can be misguided. There are no magic bullets or answers to linking effective schools to leadership productivity, but the "smoke and mirrors" assessment approach is easier to achieve than seeking the real truth. No single assessment…

  1. Student Perceptions of University Effectiveness.

    ERIC Educational Resources Information Center

    Kleemann, Gary L.; Richardson, Richard C., Jr.

    Student perceptions of the effectiveness of three state universities was studied: Arizona State University, University of Arizona, and Northern Arizona University. An operational definition of effectiveness was proposed based on the literature, and a list of organizational activities was validated by administrators, faculty, community…

  2. Herbicide Effects on Plant Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of herbicides on plant disease is an important, but generally overlooked, aspect of integrated pest management. Furthermore, these interactions can be crucial contributors to the success or failure of the biocontrol of weeds with microbes. Indirectly, through their strong effects on pla...

  3. Effects of Ritalin on Reading.

    ERIC Educational Resources Information Center

    Cooter, Robert B., Jr.

    1988-01-01

    This article describes the use of "Ritalin" to calm overactive children. The drug's side effects are reported, and research on the effect of "Ritalin" on reading performance in the classroom is reviewed. It is concluded that use of stimulant drugs to help reading underachievers is not supported by research. (Author/JDD)

  4. Fuels research: Combustion effects overview

    NASA Technical Reports Server (NTRS)

    Haggard, J. B., Jr.

    1980-01-01

    The effects of broadened property fuels on gas turbine combustors were assessed. Those physical and chemical properties of fuels that affect aviation gas turbine combustion were isolated and identified. Combustion sensitivity to variations in particular fuel properties were determined. Advanced combustion concepts and subcomponents that could lessen the effect of using broadened property fuels were also identified.

  5. Switchgrass biochar effects two aridisols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of biochar has received growing attention with regards to improving the physico-chemical properties of highly weathered Ultisols and Oxisols, yet very little research has focused on effects in Aridisols. The objective of this study was to investigate the effect of either low or high tempera...

  6. Counselor Effectiveness Through Radio Communication.

    ERIC Educational Resources Information Center

    Tentoni, Stuart C.

    This study determined the effectiveness of the use of radio as a means of providing immediate feedback on student counselors in a practicum setting. Using a non-equivalent group experimental design, 10 experimental subjects were compared to 10 control subjects with respect to counselor effectiveness. The experimental subjects were given immediate…

  7. Classroom Composition and Peer Effects

    ERIC Educational Resources Information Center

    Hattie, John A. C.

    2002-01-01

    This chapter examines the extent to which the composition of classes affects learning outcomes. The aim is to explore peer effects when students are organized into classes on the basis of ability, ethnicity, or gender, as well as the effects of multigrade and multi-age classes and class size. The argument is defended that these composition factors…

  8. Gestalt Effect of Self Assessment

    ERIC Educational Resources Information Center

    McDonald, Betty

    2012-01-01

    Defining self assessment as the involvement of students in identifying standards and/or criteria to apply to their work and making judgements about the extent to which they have met these criteria and standards, this paper seeks to highlight the gestalt effect of self assessment. The total effect of self assessment on the learner is greater than…

  9. Retrieval Effectiveness on the Web.

    ERIC Educational Resources Information Center

    Savoy, Jacques; Picard, Justin

    2001-01-01

    Discusses the role of search engines in Web usability and analyzes and evaluates the retrieval effectiveness of various indexing and searching strategies on a new Web text collection. Highlights include preprocessing techniques that might improve retrieval effectiveness; and hyperlinks as useful sources of evidence in improving retrieval…

  10. Organizational Effectiveness: A Comprehensive Bibliography.

    ERIC Educational Resources Information Center

    Cameron, Kim S., Comp.

    A bibliography on organizational effectiveness that contains approximately 515 references, dated primarily since 1970, is presented. The focus is the organizational level of analysis, rather than individual effectiveness or environmental (e.g., economy) performance. The literature included comes from the organizational sciences, higher education,…

  11. Hiring Effective Secondary School Counselors

    ERIC Educational Resources Information Center

    McGlothlin, Jason M.; Miller, Lynne Guillot

    2008-01-01

    Today's effective school counselors are integral in education reform, school leadership, and student achievement. It is typically the responsibility of building principals to hire effective school counselors. This article builds on previous literature and provides principals with questions to ask and information to gather that may be helpful in…

  12. Cumulative effects analysis (CEA) tools

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effective rangeland management requires careful consideration of the possible cumulative effects of different management options prior to making major management decisions. State-and-transition (S/T) models, based on ecological sites, capture our understanding ecosystem functioning and can be used t...

  13. Effect of surface morphology on kinetic compensation effect

    NASA Astrophysics Data System (ADS)

    Zuniga-Hansen, Nayeli; Silbert, Leonardo E.

    The existence of the kinetic compensation effect, observed in many fields of science, continues to be debated and believed to be a mathematical artifact. Recently, we performed a computational study of the thermal desorption of interacting adsorbates from an energetically homogeneous surface and we observed that the kinetic compensation effect indeed occurs to varying degrees depending on interaction strength. However, other factors which may lead to a kinetic compensation effect have yet to be explored. In the present work, using kinetic Monte Carlo simulations, we study the effects of substrate topology on thermal desorption. We focus on differences between ordered and disordered surfaces at a fixed site coordination number. The rates of desorption depend on surface configuration due to the inherent differences in the local environments of adsorbing sites. While the compensation effect persists for the disordered substrate, it is more strongly influenced by variations in the preexponential factor rather than the activation energy which dominates in the ordered lattice. We expect our results to provide a deeper insight into the microscopic events that originate compensation effects in our system of study but also in other fields where these effects have been reported.

  14. Clinical side effects during aerosol therapy: cutaneous and ocular effects.

    PubMed

    Geller, David E

    2007-01-01

    Aerosolized medications maximize clinical benefit by targeting the airways and minimize side effects by reducing (though not eliminating) systemic exposure. Aerosolized drugs delivered with a facemask may inadvertently deposit on the face and in the eyes, raising concerns about cutaneous and ocular side effects with these drugs. Cases of anisocoria have been reported from exposure of the eyes to aerosol bronchodilators. Whether inhaled corticosteroids (ICS) can cause skin and eye problems like those seen with systemic or topical steroids is more difficult to answer. Patients who take ICS may have other corticosteroid exposures, or have other conditions that predispose them to side effects, making the analysis of the ICS risk challenging. Also, many studies were not designed to search for cutaneous or ocular effects, or may have been too short to detect these effects. Nevertheless, ICS have been associated with an increased risk of skin thinning, bruising, cataracts and possibly glaucoma in adults, but not in children. The risks increase with advanced age, higher doses, and longer duration of use. In children, the risks of cataracts and glaucoma were negligible with ICS, whether a mouthpiece or a mask interface was used. Side effects like skin rash and conjunctivitis occurred at low frequencies similar to placebo or comparator drugs. We do not know whether exposed children will have increased risks from ICS later in life. Therefore, it is wise to avoid face and eye deposition when possible, and to use the minimally effective dose. PMID:17411401

  15. Media Effects: Theory and Research.

    PubMed

    Valkenburg, Patti M; Peter, Jochen; Walther, Joseph B

    2016-01-01

    This review analyzes trends and commonalities among prominent theories of media effects. On the basis of exemplary meta-analyses of media effects and bibliometric studies of well-cited theories, we identify and discuss five features of media effects theories as well as their empirical support. Each of these features specifies the conditions under which media may produce effects on certain types of individuals. Our review ends with a discussion of media effects in newer media environments. This includes theories of computer-mediated communication, the development of which appears to share a similar pattern of reformulation from unidirectional, receiver-oriented views, to theories that recognize the transactional nature of communication. We conclude by outlining challenges and promising avenues for future research. PMID:26331344

  16. Mass-independent isotope effects.

    PubMed

    Buchachenko, Anatoly L

    2013-02-28

    Three fundamental properties of atomic nuclei-mass, spin (and related magnetic moment), and volume-are the source of isotope effects. The mostly deserved and popular, with almost hundred-year history, is the mass-dependent isotope effect. The first mass-independent isotope effect which chemically discriminates isotopes by their nuclear spins and nuclear magnetic moments rather than by their masses was detected in 1976. It was named as the magnetic isotope effect because it is controlled by magnetic interaction, i.e., electron-nuclear hyperfine coupling in the paramagnetic species, the reaction intermediates. The effect follows from the universal physical property of chemical reactions to conserve angular momentum (spin) of electrons and nuclei. It is now detected for oxygen, silicon, sulfur, germanium, tin, mercury, magnesium, calcium, zinc, and uranium in a great variety of chemical and biochemical reactions including those of medical and ecological importance. Another mass-independent isotope effect was detected in 1983 as a deviation of isotopic distribution in reaction products from that which would be expected from the mass-dependent isotope effect. On the physical basis, it is in fact a mass-dependent effect, but it surprisingly results in isotope fractionation which is incompatible with that predicted by traditional mass-dependent effects. It is supposed to be a function of dynamic parameters of reaction and energy relaxation in excited states of products. The third, nuclear volume mass-independent isotope effect is detected in the high-resolution atomic and molecular spectra and in the extraction processes, but there are no unambiguous indications of its importance as an isotope fractionation factor in chemical reactions. PMID:23301791

  17. Features which separate least effective from most effective science teachers

    NASA Astrophysics Data System (ADS)

    Yager, Robert E.; Hidayat, Eddy M.; Penick, John E.

    Sixty-one science supervisors identified 321 teachers, 162 most effective and 159 least effective, in their respective districts. Information was then sought concerning age, gender, teaching field(s), number of preparations, amount of preparation, time, semester hours of undergraduate science preparation, quantity of graduate science preparation, type of teacher education programs, number of weeks of NSF workshop experience, and number of workshops elected for participation. Comparisons of the information gathered between least and most effective teachers were made. There were no differences in any categories except for gender, quantity of NSF institute experiences, and elected in-service experiences in excess of a single day's duration. Many of the factors frequently used to differentiate among teachers do not provide any explanation of the differences between least and most effective teachers of science.

  18. IMPROVING MEASURES OF BIOLOGIC EFFECT: MEASURING EFFECTS IN HUMAN MALES.

    EPA Science Inventory

    Animal toxicology studies have demonstrated spermatogenesis and sperm quality effects after exposure to DCA, BDCM, chloral hydrate and DBA. Population-based field studies to identify human male reproductive risks of DBPs require preliminary work to develop specific epidemiologi...

  19. IMPROVING MEASURES OF BIOLOGIC EFFECT: MEASURING EFFECTS IN HUMAN MALES

    EPA Science Inventory

    Animal toxicology studies have demonstrated spermatogenesis and sperm quality effects after exposure to several drinking water disinfection byproducts (DBPs), including DCA, BDCM, chloral hydrate and DBA. Population-based field studies to identify human male reproductive risks o...

  20. Wohlleben Effect (paramagnetic Meissner Effect) in high-temperature superconductors

    SciTech Connect

    Khomskii, D. |

    1994-04-01

    Recently a quite unexpected phenomenon was observed during the study of the magnetic properties of High-T{sub c} superconductors: In the field-cooled regime the magnetic response of some HTSC at very low fields ({le} 1 Oe), instead of being diamagnetic, becomes paramagnetic. Such behavior is perfectly reproducible and stable. This effect is now called the Wohlleben Effect. The samples showing the Wohlleben effect also display anomalous behavior in some other properties (microwave absorption, second harmonic of magnetic susceptibility). In this paper a survey is given of the experimental studies of this and related phenomena, carried out in different laboratories. Corresponding theoretical models are also discussed. The effect is attributed to the formation of spontaneous currents (spontaneous orbital magnetic moments) in the ground state of the weak link network in case when Josephson coupling between certain grains is negative ({pi}-contacts). Microscopic mechanisms of inverse Josephson coupling are discussed especially in connection with the possible unconventional pairing in HTSC.

  1. Confinement Effect on the Effective Viscosity of Plasticized Polymer Films

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Peng, D.; Ogata, Y.; Tanaka, K.; Yang, Z.; Fujii, Y.; Yamada, N. L.; Lam, C. H.; Tsui, Ophelia K. C.

    We have measured the effective viscosity of polystyrene films with a small (4 wt%) added amount of dioctyl phthalate (DOP) deposited on silica. A broad range of molecular weights, Mw, from 13.7 to 2,100 kg/mol was investigated. Our result shows that for the thin films with Mw <~100 kg/mol, the addition of DOP causes the effective viscosity to decrease by a factor of ~4, independent of Mw. But for the higher Mw films, the effective viscosity of the DOP added films creeps towards that of the neat films with increasing Mw. A model assuming the effective viscosity to be dominated by enhanced surface mobility for the lower Mw films, but surface-promoted interfacial slippage for the higher Mw films is able to account for the experimental observations. We are grateful to the support of National Science Foundation through the project DMR-1310536.

  2. Mitigation of Space Radiation Effects

    NASA Astrophysics Data System (ADS)

    Atwell, William

    2012-02-01

    During low earth orbit and deep space missions, humans and spacecraft systems are exposed to high energy particles emanating from basically three sources: geomagnetically-trapped protons and electrons (Van Allen Belts), extremely high energy galactic cosmic radiation (GCR), and solar proton events (SPEs). The particles can have deleterious effects if not properly shielded. For humans, there can be a multitude of harmful effects depending on the degree of exposure. For spacecraft systems, especially electronics, the effects can range from single event upsets (SEUs) to catastrophic effects such as latchup and burnout. In addition, some materials, radio-sensitive experiments, and scientific payloads are subject to harmful effects. To date, other methods have been proposed such as electrostatic and electromagnetic shielding, but these approaches have not proven feasible due to cost, weight, and safety issues. The only method that has merit and has been effective is bulk or parasitic shielding. In this paper, we discuss in detail the sources of the space radiation environment, spacecraft, human, and onboard systems modeling methodologies, transport of these particles through shielding materials, and the calculation of the dose effects. In addition, a review of the space missions to date and a discussion of the space radiation mitigation challenges for lunar and deep space missions such as lunar outposts and human missions to Mars are presented.

  3. Late effects from hadron therapy

    SciTech Connect

    Blakely, Eleanor A.; Chang, Polly Y.

    2004-06-01

    Successful cancer patient survival and local tumor control from hadron radiotherapy warrant a discussion of potential secondary late effects from the radiation. The study of late-appearing clinical effects from particle beams of protons, carbon, or heavier ions is a relatively new field with few data. However, new clinical information is available from pioneer hadron radiotherapy programs in the USA, Japan, Germany and Switzerland. This paper will review available data on late tissue effects from particle radiation exposures, and discuss its importance to the future of hadron therapy. Potential late radiation effects are associated with irradiated normal tissue volumes at risk that in many cases can be reduced with hadron therapy. However, normal tissues present within hadron treatment volumes can demonstrate enhanced responses compared to conventional modes of therapy. Late endpoints of concern include induction of secondary cancers, cataract, fibrosis, neurodegeneration, vascular damage, and immunological, endocrine and hereditary effects. Low-dose tissue effects at tumor margins need further study, and there is need for more acute molecular studies underlying late effects of hadron therapy.

  4. Maxwell-Garnett effective medium theory: Quantum nonlocal effects

    SciTech Connect

    Moradi, Afshin

    2015-04-15

    We develop the Maxwell-Garnett theory for the effective medium approximation of composite materials with metallic nanoparticles by taking into account the quantum spatial dispersion effects in dielectric response of nanoparticles. We derive a quantum nonlocal generalization of the standard Maxwell-Garnett formula, by means the linearized quantum hydrodynamic theory in conjunction with the Poisson equation as well as the appropriate additional quantum boundary conditions.

  5. Paramagnetic Meissner effect in Nb

    SciTech Connect

    Kostic, P.; Veal, B.; Paulikas, A.P.; Welp, U.; Todt, V.R.; Gu, C.; Geiser, U.; Williams, J.M.; Carlson, K.D.; Klemm, R.A.

    1996-01-01

    The paramagnetic Meissner effect (PME), or Wohlleben effect, in which the field-cooled magnetization of superconducting samples is paramagnetic below {ital T}{sub {ital c}}, has been reported to occur in some samples of a variety of high-{ital T}{sub {ital c}} cuprate superconductors. It has been proposed that the effect arose in granular hole-doped cuprates from current loops with {pi} phase shifts of the superconducting order parameter at some grain-boundary junctions. It is argued that such behavior would be expected to occur in a {ital d}-wave superconductor, but not in a conventional {ital s}-wave superconductor. To test this hypothesis, we have searched for the occurrence of the effect in Nb, and have confirmed a recent report by Minhaj {ital et} {ital al}. of its occurrence in some Nb samples. For these studies, the effects of stray fields and field gradients in the measurement volume of the superconducting quantum interference device magnetometer have been carefully considered to rule out the possibility that measurement artifacts might be responsible for the apparent paramagnetic behavior in Nb. The {ital M}({ital T}) and {ital M}({ital H}) curves obtained in Nb samples that show the PME also show remarkably strong resemblance to those curves reported for the cuprate materials exhibiting the PME. Evidence is presented that the effect arises from inhomogeneously trapped flux, and is strongly influenced by sample geometry and surface effects. These results suggest that, for the effect to be observable, {ital T}{sub {ital c}} on the sample surface must be different from the bulk {ital T}{sub {ital c}}. The occurrence of the PME in Nb strongly suggests that the observation of this effect is unrelated to {ital d}-wave superconductivity. {copyright} {ital 1996 The American Physical Society.}

  6. Effective-surface-energy approach for size effects in ferroics

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Tagantsev, Alexander K.; Setter, Nava

    2015-03-01

    We present a simple approach enabling analytical treatments of size effects in ferroelectric samples of complicated shapes for the cases where long-range depolarizing effects are not involved. The key element of the approach is the presentation of the energy of the system as the sum of the bulk and effective surface energy (like in the classical nucleation problem), while the latter is expressed as a function of the bulk value of the order parameter. The effective surface energy is calculated in terms of the Kretschmer-Binder framework. The size-driven shift of TC in the ferroelectric thin films with in-plane polarization and the nanowires with axial polarization is studied using the proposed approach and the results are compared with those exact. In the limit of large extrapolation length, the approach reproduces the exact results (analytical and numerical). For short extrapolation lengths, it can provide a good approximation to the exact results for the case of second-order phase transitions. For ferroelectrics with the first-order phase transition having the maximal correlation length smaller than the extrapolation length (a common situation in perovskites), the approach provides as well an appropriate description of the size effect on the transition temperature. The proposed approach can be used for the description of the size effect not only in ferroelectrics, but in other ferroics as well.

  7. Quark and pion effective couplings from polarization effects

    NASA Astrophysics Data System (ADS)

    Braghin, Fábio L.

    2016-05-01

    A flavor SU(2) effective model for pions and quarks is derived by considering polarization effects departing from the usual quark-quark effective interaction induced by dressed gluon exchange, i.e. a global color model for QCD. For that, the quark field is decomposed into a component that yields light mesons and the quark-antiquark condensate, being integrated out by means of the auxiliary field method, and another component which yields constituent quarks, which is basically a background quark field. Within a long-wavelength and weak quark field expansion (or large quark effective mass expansion) of a quark determinant, the leading terms are found up to the second order in a zero-order derivative expansion, by neglecting vector mesons that are considerably heavier than the pion. Pions are considered in the structureless limit and, besides the chiral invariant terms that reproduce previously derived expressions, symmetry breaking terms are also presented. The leading chiral quark-quark effective couplings are also found corresponding to a NJL and a vector-NJL couplings. All the resulting effective coupling constants and parameters are expressed in terms of the current and constituent quark masses and of the coupling g.

  8. Environmental effects on spacecraft materials

    NASA Technical Reports Server (NTRS)

    Haffner, J. W.

    1989-01-01

    The effects on the natural space environments on materials are presented, which may be used for SDI applications. The current state-of-the-art knowledge of those effects was studied, and a literature search, a questionnaire mailing, and some visits to NASA and Air Force research facilities were performed. Phase 2 will be a study of what materials may be used for SDI applications and to what natural space environments they may be vulnerable. Deficiencies in knowledge of the effects of the natural space environments on these materials are to be identified and recommendations are to be made to eliminate these knowledge deficiencies.

  9. Pharmacological effects of rosa damascena.

    PubMed

    Boskabady, Mohammad Hossein; Shafei, Mohammad Naser; Saberi, Zahra; Amini, Somayeh

    2011-07-01

    Rosa damascena mill L., known as Gole Mohammadi in is one of the most important species of Rosaceae family flowers. R. damascena is an ornamental plant and beside perfuming effect, several pharmacological properties including anti-HIV, antibacterial, antioxidant, antitussive, hypnotic, antidiabetic, and relaxant effect on tracheal chains have been reported for this plant. This article is a comprehensive review on pharmacological effects of R. damascena. Online literature searches were performed using Medline, medex, Scopus, and Google Scholar websites backed to 1972 to identify researches about R. damascena. Searches also were done by going through the author's files and the bibliographies of all located papers. PMID:23493250

  10. Interference effects in potential wells

    NASA Astrophysics Data System (ADS)

    Mullin, W. J.; Laloë, F.

    2015-05-01

    We propose using an array of potential wells as an interferometer in which the beam splitters are provided by tunneling during an appropriate time through the barrier between wells. This arrangement allows demonstration of generalized Hong-Ou-Mandel effects with multiple particles traversing one or several beam splitters. Other interferometer effects can occur, including a violation of the Bell-Clauser-Horne-Shimony-Holt form of the Bell inequality. With interactions, one sees various effects, including so-called fermionization, collective tunneling, and self-trapping.

  11. Calibration effects on orbit determination

    NASA Technical Reports Server (NTRS)

    Madrid, G. A.; Winn, F. B.; Zielenbach, J. W.; Yip, K. B.

    1974-01-01

    The effects of charged particle and tropospheric calibrations on the orbit determination (OD) process are analyzed. The calibration process consisted of correcting the Doppler observables for the media effects. Calibrated and uncalibrated Doppler data sets were used to obtain OD results for past missions as well as Mariner Mars 1971. Comparisons of these Doppler reductions show the significance of the calibrations. For the MM'71 mission, the media calibrations proved themselves effective in diminishing the overall B-plane error and reducing the Doppler residual signatures.

  12. Neurological effects of deep diving.

    PubMed

    Grønning, Marit; Aarli, Johan A

    2011-05-15

    Deep diving is defined as diving to depths more than 50 m of seawater (msw), and is mainly used for occupational and military purposes. A deep dive is characterized by the compression phase, the bottom time and the decompression phase. Neurological and neurophysiologic effects are demonstrated in divers during the compression phase and the bottom time. Immediate and transient neurological effects after deep dives have been shown in some divers. However, the results from the epidemiological studies regarding long term neurological effects from deep diving are conflicting and still not conclusive. Prospective clinical studies with sufficient power and sensitivity are needed to solve this very important issue. PMID:21377169

  13. Pharmacological Effects of Rosa Damascena

    PubMed Central

    Boskabady, Mohammad Hossein; Shafei, Mohammad Naser; Saberi, Zahra; Amini, Somayeh

    2011-01-01

    Rosa damascena mill L., known as Gole Mohammadi in is one of the most important species of Rosaceae family flowers. R. damascena is an ornamental plant and beside perfuming effect, several pharmacological properties including anti-HIV, antibacterial, antioxidant, antitussive, hypnotic, antidiabetic, and relaxant effect on tracheal chains have been reported for this plant. This article is a comprehensive review on pharmacological effects of R. damascena. Online literature searches were performed using Medline, medex, Scopus, and Google Scholar websites backed to 1972 to identify researches about R. damascena. Searches also were done by going through the author's files and the bibliographies of all located papers. PMID:23493250

  14. Novel effects of nitric oxide

    NASA Technical Reports Server (NTRS)

    Davis, K. L.; Martin, E.; Turko, I. V.; Murad, F.

    2001-01-01

    Nitric oxide (NO), a simple free radical gas, elicits a surprisingly wide range of physiological and pathophysiological effects. NO interacts with soluble guanylate cyclase to evoke many of these effects. However, NO can also interact with molecular oxygen and superoxide radicals to produce reactive nitrogen species that can modify a number of macromolecules including proteins, lipids, and nucleic acids. NO can also interact directly with transition metals. Here, we have reviewed the non--3',5'-cyclic-guanosine-monophosphate-mediated effects of NO including modifications of proteins, lipids, and nucleic acids.

  15. Dissipative Effects on Quantum Sticking

    NASA Astrophysics Data System (ADS)

    Zhang, Yanting; Clougherty, Dennis

    2011-03-01

    Using variational mean-field theory, many-body dissipative effects on the threshold law for quantum sticking and reflection of neutral particles are examined. For the case of an ohmic bosonic bath, we study the effects of the infrared divergence on the probability of sticking and obtain an analytic expression for the rate of sticking as an asymptotic expansion in the incident energy E . The low-energy threshold law for quantum sticking is found to be robust with respect to many-body effects and remains a universal scaling law to leading order in E . Non-universal many-body effects alter the coefficient of the rate law and the exponent of a subdominant term. We gratefully acknowledge support from NSF under DMR-0814377.

  16. Prevalence effect in haptic search

    PubMed Central

    Ishibashi, Kazuya; Watanabe, Ken; Takaoka, Yutaka; Watanabe, Tetsuya; Kita, Shinichi

    2012-01-01

    In visual search tasks, the ratio of target-present to target-absent trials has important effects on miss rates. In this study, we examined whether the target prevalence effect occurs in a haptic search task by using artificial tactile maps. The results indicated that target prevalence has effects on miss rates, sensitivity, and criterion. Moreover, an increase in miss rates in the low-prevalence condition (10%) was strongly correlated with a decrease in search termination times (target-absent reaction times). These results suggest that the prevalence effect on haptic search is caused by a decrease in the search termination time and a shift in decision criterion and a decrease in sensitivity. PMID:23145300

  17. Antiartherosclerotic Effects of Plant Flavonoids

    PubMed Central

    Gunasekaran, Baskaran; Shukor, Mohd Yunus

    2014-01-01

    Atherosclerosis is the process of hardening and narrowing the arteries. Atherosclerosis is generally associated with cardiovascular diseases such as strokes, heart attacks, and peripheral vascular diseases. Since the usage of the synthetic drug, statins, leads to various side effects, the plants flavonoids with antiartherosclerotic activity gained much attention and were proven to reduce the risk of atherosclerosis in vitro and in vivo based on different animal models. The flavonoids compounds also exhibit lipid lowering effects and anti-inflammatory and antiatherogenic properties. The future development of flavonoids-based drugs is believed to provide significant effects on atherosclerosis and its related diseases. This paper discusses the antiatherosclerotic effects of selected plant flavonoids such as quercetin, kaempferol, myricetin, rutin, naringenin, catechin, fisetin, and gossypetin. PMID:24971331

  18. Unparticle effects in neutrino telescopes

    SciTech Connect

    Gonzalez-Sprinberg, G.; Martinez, R.; Sampayo, Oscar A.

    2009-03-01

    Recently H. Georgi has introduced the concept of unparticles in order to describe the low energy physics of a nontrivial scale invariant sector of an effective theory. We investigate its physical effects on the neutrino flux to be detected in a kilometer cubic neutrino telescope such as IceCube. We study the effects, on different observables, of the survival neutrino flux after through the Earth, and the regeneration originated in the neutral currents. We calculate the contribution of unparticle physics to the neutrino-nucleon interaction and, then, to the observables in order to evaluate detectable effects in IceCUbe. Our results are compared with the bounds obtained by other nonunderground experiments. Finally, the results are presented as an exclusion plot in the relevant parameters of the new physics stuff.

  19. HEALTH EFFECTS ASSESSMENT FOR ACRYLONITRILE

    EPA Science Inventory

    The report summarizes and evaluates information relevant to a preliminary interim assessment of adverse health effects associated with specific chemicals or compounds. The Office of Emergency and Remedial Response (Superfund) uses these documents in preparing cost-benefit analyse...

  20. Health Effects Assessment for Bromomethane

    EPA Science Inventory

    The report summarizes and evaluates information relevant to a preliminary interim assessment of adverse health effects associated with specific chemicals or compounds. The Office of Emergency and Remedial Response (Superfund) uses these documents in preparing cost-benefit analyse...

  1. Radiological Effects of Nuclear War.

    ERIC Educational Resources Information Center

    Shapiro, Charles S.

    1988-01-01

    Described are the global effects of nuclear war. Discussed are radiation dosages, limited nuclear attacks, strategic arms reductions, and other results reported at the workshop on nuclear war issues in Moscow in March 1988. (CW)

  2. Sequential products on effect algebras

    NASA Astrophysics Data System (ADS)

    Gudder, Stan; Greechie, Richard

    2002-02-01

    A sequential effect algebra (SEA) is an effect algebra on which a sequential product with natural properties is defined. The properties of sequential products on Hilbert space effect algebras are discussed. For a general SEA, relationships between sequential independence, coexistence and compatibility are given. It is shown that the sharp elements of a SEA form an orthomodular poset. The sequential center of a SEA is discussed and a characterization of when the sequential center is isomorphic to a fuzzy set system is presented. It is shown that the existence, of a sequential product is a strong restriction that eliminates many effect algebras from being SEA's. For example, there are no finite nonboolean SEA's, A measure of sharpness called the sharpness index is studied. The existence of horizontal sums of SEA's is characterized and examples of horizontal sums and tensor products are presented.

  3. Ethnicity effects in relative pitch.

    PubMed

    Hove, Michael J; Sutherland, Mary Elizabeth; Krumhansl, Carol L

    2010-06-01

    Absolute pitch (AP), the rare ability to identify a musical pitch, occurs at a higher rate among East Asian musicians. This has stimulated considerable research on the comparative contributions of genetic and environmental factors. Two studies examined whether a similar ethnicity effect is found for relative pitch (RP), identifying the distance or interval between two tones. Nonmusicians (n = 103) were trained to label musical intervals and were subsequently tested on interval identification. We establish similar ethnicity effects: Chinese and Korean participants consistently outperformed other participants in RP tasks, but not in a "relative rhythm" control task. This effect is not driven by previous musical or tone-language experience. The parallel with the East Asian advantage for AP suggests that enhanced perceptual-cognitive processing of pitch is more general and is not limited to highly trained musicians. This effect opens up many research questions concerning the environmental and genetic contributions related to this more general pitch-based ability. PMID:20551351

  4. Magnetic effects in anomalous dispersion

    SciTech Connect

    Blume, M.

    1992-12-31

    Spectacular enhancements of magnetic x-ray scattering have been predicted and observed experimentally. These effects are the result of resonant phenomena closely related to anomalous dispersion, and they are strongest at near-edge resonances. The theory of these resonances will be developed with particular attention to the symmetry properties of the scatterer. While the phenomena to be discussed concern magnetic properties the transitions are electric dipole or electric quadrupole in character and represent a subset of the usual anomalous dispersion phenomena. The polarization dependence of the scattering is also considered, and the polarization dependence for magnetic effects is related to that for charge scattering and to Templeton type anisotropic polarization phenomena. It has been found that the strongest effects occur in rare-earths and in actinides for M shell edges. In addition to the scattering properties the theory is applicable to ``forward scattering`` properties such as the Faraday effect and circular dichroism.

  5. CONTAMINATED SEDIMENTS - ECOLOGICAL EFFECTS RESEARCH

    EPA Science Inventory

    NHEERL's research in this area focuses on ecological effects of bioaccumulative chemicals, such as PCBs. The research is designed with recognition that sites of different size and complexity require bioaccumulation models with correspondingly complex and/or extensive data requir...

  6. Biological Effects of Directed Energy

    NASA Astrophysics Data System (ADS)

    Dayton, Thomas; Beason, Charles; Hitt, M. K.; Rogers, Walter; Cook, Michael

    2002-11-01

    This Final Report summarizes the biological effects research conducted by Veridian Engineering personnel under contract F41624-96-C-9009 in support of the Air Force Research Laboratory's Radio Frequency Radiation Branch from April 1997 to April 2002. Biological effects research and consultation were provided in five major areas: Active Denial System (also known as Vehicle Mounted Active Denial System), radio frequency radiation (RFR) health and safety, non-lethal weapon biological effects research, the newly formed Joint Non-Lethal Weapons Human Effects Center of Excellence, and Biotechnology. The report is organized by research efforts within the major research areas, providing title, objective, a brief description, relevance to the AF or DoD, funding, and products.

  7. How Effective Is Male Contraception?

    MedlinePlus

    ... Trials Resources and Publications How effective is male contraception? Skip sharing on social media links Share this: ... health care providers to determine which method of birth control is best for them. For men, methods of ...

  8. Photothermoelectric Effects in Nanoporous Silicon.

    PubMed

    Lai, Yu-Sheng; Tsai, Chao-Yang; Chang, Chin-Kai; Huang, Cheng-Yin; Hsiao, Vincent K S; Su, Yuhlong Oliver

    2016-04-01

    The first observation of the photothermoelectric effect in a nanoporous silicon (NPSi) device indicates that the photocurrent is dependent on the position of light-induced local heating from illumination at the Au-electrode/NPSi interface. PMID:26821828

  9. Loudness, noisiness, and vibration effects

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The physical measurement of noise that determines psychological and physical behavioral effects in real life is investigated. The roles of loudness and noisiness judgement in the development of these measurement procedures are also examined.

  10. Electromagnetically induced angular Talbot effect

    NASA Astrophysics Data System (ADS)

    Qiu, Tianhui; Yang, Guojian

    2015-12-01

    The discrete angular spectrum (angular Talbot effect) of a periodic grating illuminated by a suitable spherical wave front has been observed recently (Azaña and Chatellus 2104 Phys. Rev. Lett. 112 213902). In this paper we study the possibility of such a phenomenon being realized with a medium that has no macroperiodic structure itself. Tunable electromagnetically induced grating (EIG) could be such a kind of medium. We obtain an EIG based on the periodically modulated strong susceptibility due to the third-order nonlinear effect generated in a double Λ-type four-level atomic system, and show the angular Talbot effect of an amplitude EIG, as well as a hybrid EIG, as the condition of the discrete phase-modulation shift of the illumination light front is satisfied. EIG parameters are tunable and the EIG-based angular Talbot effect may have the same potential applications as its periodic grating counterpart has.

  11. Psychological effects of thought acceleration.

    PubMed

    Pronin, Emily; Jacobs, Elana; Wegner, Daniel M

    2008-10-01

    Six experiments found that manipulations that increase thought speed also yield positive affect. These experiments varied in both the methods used for accelerating thought (i.e., instructions to brainstorm freely, exposure to multiple ideas, encouragement to plagiarize others' ideas, performance of easy cognitive tasks, narration of a silent video in fast-forward, and experimentally controlled reading speed) and the contents of the thoughts that were induced (from thoughts about money-making schemes to thoughts of five-letter words). The results suggested that effects of thought speed on mood are partially rooted in the subjective experience of thought speed. The results also suggested that these effects can be attributed to the joy-enhancing effects of fast thinking (rather than only to the joy-killing effects of slow thinking). This work is inspired by observations of a link between "racing thoughts" and euphoria in cases of clinical mania, and potential implications of that observed link are discussed. PMID:18837610

  12. Topological Insulator and Thermoelectric Effects

    NASA Astrophysics Data System (ADS)

    Xu, Yong

    The recent discovery of topological insulator (TI) offers new opportunities for the development of thermoelectricity, because many TIs (like Bi2Te3) are excellent thermoelectric materials. In this talk, I will first introduce our theoretical predictions of anomalous Seebeck effect and strong size effect in TI [PRL 112, 226801 (2014)]. Then I will report our recent proof experiments, which find in TI thin films that (i) the hole-type Seebeck effect and the electron-type Hall effect coexist in the same TI sample for all the measured temperatures (up to 300 K), and (ii) the thermoelectric properties depend sensitively on the film thickness. The unconventional phenomena are revealed to be closely related to the topological nature of the material. These findings may inspire new ideas for designing TI-based high-efficiency thermoelectric devices.

  13. Health Effects of Climate Change

    MedlinePlus

    ... For example, existing investments in research on air pollution and respiratory disease; characteristics of vector range; and effects of acute and chronic exposure to agricultural chemicals are yielding important research advances that may ...

  14. ECOLOGICAL EFFECTS OF GENE FLOW.

    EPA Science Inventory

    The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and the Government Performance Results Act (GPRA, goal number four for Safe Communities), constitute the statutory authority and strategic framework respectively, for Agency research on non-target effects of pestici...

  15. Health effects of smokeless tobacco

    SciTech Connect

    Not Available

    1986-02-28

    Pharmacologic and physiologic effects of snuff and chewing tobacco include the gamut of cardiovascular, endocrinologic, neurologic, and psychological effects that are associated with nicotine. A review of studies appearing in the scientific literature involving various populations and approaches indicates that the use of snuff or chewing tobacco is associated with a variety of serious adverse effects and especially with oral cancer. The studies suggest that snuff and chewing tobacco also may affect reproduction, longevity, the cardiovascular system, and oral health. The Council on Scientific Affairs concludes there is evidence demonstrating that use of snuff or chewing tobacco is associated with adverse health effects such as oral cancer, urges the implementation of well-planned and long-term studies that will further define the risks of using snuff and chewing tobacco, and recommends that the restrictions applying to the advertising of cigarettes also be applied to the advertising of snuff and chewing tobacco.

  16. Radiation effects on structural materials

    SciTech Connect

    Ghoniem, N.M.

    1991-06-28

    This report discusses the following topics on the effect radiation has on thermonuclear reactor materials: Atomic Displacements; Microstructure Evolution; Materials Engineering, Mechanics, and Design; Research on Low-Activation Steels; and Research Motivated by Grant Support.

  17. Side Effects of Smallpox Vaccination

    MedlinePlus

    ... Index SMALLPOX FACT SHEET Side Effects of Smallpox Vaccination The smallpox vaccine prevents smallpox. For most people, ... go away without treatment: The arm receiving the vaccination may be sore and red where the vaccine ...

  18. Side Effects and Their Management

    MedlinePlus

    Donate Donate One Time Monthly Event Tribute For brain tumor information and support Call: 800-886-ABTA (2282) ... Care and Treatment Newly Diagnosed Continuum of Care Brain Tumor Treatments Brain Tumor Treatment Locations Treatment Side Effects & ...

  19. Health Effects Assessment for Ammonia

    EPA Science Inventory

    The report summarizes and evaluates information relevant to a preliminary interim assessment of adverse health effects associated with specific chemicals or compounds. The Office of Emergency and Remedial Response (Superfund) uses these documents in preparing cost-benefit analyse...

  20. Neurocognitive effects of alcohol hangover.

    PubMed

    Prat, Gemma; Adan, Ana; Pérez-Pàmies, Montserrat; Sànchez-Turet, Miquel

    2008-01-01

    Alcohol hangover is characterized by adverse physical and mental effects that occur the next morning after the intake of toxic doses of alcohol. One of the more relevant functional consequences of hangover is the cognitive and subjective impairment, which could be related to the high socioeconomic costs of alcohol consumption. Nevertheless, few studies have addressed the study of neurocognitive and subjective effects of hangover. The systematic and exhaustive study of neurocognitive and subjective effects has not been done. In the present work we briefly review the hangover impact, not only in the objective execution of attention, psychomotricity and memory tasks, but in the subjective state of the subjects as well. Moreover, we also highlight the methodology difficulties to study neurocognitive effects of hangover and suggest several aspects to take into account in future investigations. PMID:17543471