989 research outputs found

    Potentialities of proteinoids for nutritional investigation

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    Simultaneous synthesis of amino acids and proteinoid production for nutritional investigatio

    Effects of Tropical Storm Agnes on Nutrient Flux and Distribution in Lower Chesapeake Bay

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    Nutrient concentrations measured in lower Chesapeake Bay in the summer of 1972 immediately following the flooding associated with Tropical Storm Agnes are compared with those in the summer of 1973, a season of more normal rainfall. The large amount of land runoff produced unseasonably high concentrations of dissolved inorganic nitrogen in the Bay near the mouth of the Potomac River. Phosphate concentrations were essentially unaffected by the flooding. Fluxes of total nitrogen and total phosphorus nutrients through the mouth of Chesapeake Bay were calculated for both summers. The calculated net export of nutrients from the Bay in both August 1972, and June 1973 was found to be small in comparison to nutrient inputs.https://scholarworks.wm.edu/vimsbooks/1068/thumbnail.jp

    On the attitudinal consequences of being mindful: Links between mindfulness and attitudinal ambivalence

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    ArticleThis is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.A series of studies examined whether mindfulness is associated with the experience of attitudinal ambivalence. Studies 1A and 1B found that mindful individuals expressed greater comfort holding ambivalent views and reported feeling ambivalent less often. More mindful individuals also responded more positively to feelings of uncertainty (as assessed in Study 1B). Study 2 replicated these effects and demonstrated that mindful individuals had lower objective and subjective ambivalence across a range of attitude objects but did not differ in attitude valence, extremity, positivity/negativity, strength, or the need to evaluate. Study 3 showed that the link between greater ambivalence and negative affect was buffered by mindfulness, such that there was no link between the amount of ambivalence and negative affect among more mindful individuals. The results are discussed with respect to the benefits of mindfulness in relation to ambivalence and affect.Parts of this article were funded by a Leverhulme Trust Research Project Grant awarded to the first author

    Electron-phonon coupling in the conventional superconductor YNi2_2B2_2C at high phonon energies studied by time-of-flight neutron spectroscopy

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    We report an inelastic neutron scattering investigation of phonons with energies up to 159 meV in the conventional superconductor YNi2_2B2_2C. Using the SWEEP mode, a newly developed time-of-flight technique involving the continuous rotation of a single crystal specimen, allowed us to measure a four dimensional volume in (Q,E) space and, thus, determine the dispersion surface and linewidths of the A1gA_{1g} (~ 102 meV) and AuA_u (~ 159 meV) type phonon modes for the whole Brillouin zone. Despite of having linewidths of Γ=10meV\Gamma = 10 meV, A1gA_{1g} modes do not strongly contribute to the total electron-phonon coupling constant λ\lambda. However, experimental linewidths show a remarkable agreement with ab-initio calculations over the complete phonon energy range demonstrating the accuracy of such calculations in a rare comparison to a comprehensive experimental data set.Comment: accepted for publication in PR

    Ultrafast Laser-Induced Melting of Long-Range Magnetic Order in Multiferroic TbMnO3

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    We performed ultrafast time-resolved near-infrared pump, resonant soft X-ray diffraction probe measurements to investigate the coupling between the photoexcited electronic system and the spin cycloid magnetic order in multiferroic TbMnO3 at low temperatures. We observe melting of the long range antiferromagnetic order at low excitation fluences with a decay time constant of 22.3 +- 1.1 ps, which is much slower than the ~1 ps melting times previously observed in other systems. To explain the data we propose a simple model of the melting process where the pump laser pulse directly excites the electronic system, which then leads to an increase in the effective temperature of the spin system via a slower relaxation mechanism. Despite this apparent increase in the effective spin temperature, we do not observe changes in the wavevector q of the antiferromagnetic spin order that would typically correlate with an increase in temperature under equilibrium conditions. We suggest that this behavior results from the extremely low magnon group velocity that hinders a change in the spin-spiral wavevector on these time scales.Comment: 9 pages, 4 figure

    High-Frequency Spin Waves in YBa2Cu3O6.15

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    Pulsed neutron spectroscopy is used to make absolute measurements of the dynamic magnetic susceptibility of insulating YBa2Cu3O6.15. Acoustic and optical modes, derived from in- and out-of-phase oscillation of spins in adjacent CuO2 planes, dominate the spectra and are observed up to 250 meV. The optical modes appear first at 74 meV. Linear-spin-wave theory gives an excellent description of the data and yields intra- and inter-layer exchange constants of J_parallel =125 meV and J_perp = 11 meV respectively and a spin-wave intensity renormalization Z_chi = 0.4.Comment: postscript, 11 pages, 4 figures, Fig.2 fixe
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