285 research outputs found

    Evaluating annual changes in soil productivity

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    Cover title."Revision of Bulletin 405."Includes bibliographical references

    Wartime recommendations on the use of commercial fertilizer

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    Caption title.Digitized 2006 AES MoU

    Evaluating annual changes in soil productivity

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    Cover title.Includes bibliographical references

    Liming Missouri soils

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    Caption title.Digitized 2006 AES MoU

    The thermal equation of state of FeTiO_3 ilmenite based on in situ X-ray diffraction at high pressures and temperatures

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    We present in situ measurements of the unit-cell volume of a natural terrestrial ilmenite (Jagersfontein mine, South Africa) and a synthetic reduced ilmenite (FeTiO_3) at simultaneous high pressure and high temperature up to 16 GPa and 1273 K. Unit-cell volumes were determined using energy-dispersive synchrotron X-ray diffraction in a multi-anvil press. Mössbauer analyses show that the synthetic sample contained insignificant amounts of Fe^(3+) both before and after the experiment. Results were fit to Birch-Murnaghan thermal equations of state, which reproduce the experimental data to within 0.5 and 0.7 GPa for the synthetic and natural samples, respectively. At ambient conditions, the unit-cell volume of the natural sample [V_0 = 314.75 ± 0.23 (1 ) Å^3] is significantly smaller than that of the synthetic sample [V_0 = 319.12 ± 0.26 Å^3]. The difference can be attributed to the presence of impurities and Fe^(3+) in the natural sample. The 1 bar isothermal bulk moduli K_(T0) for the reduced ilmenite is slightly larger than for the natural ilmenite (181 ± 7 and 165 ± 6 GPa, respectively), with pressure derivatives K_0' = 3 ± 1. Our results, combined with literature data, suggest that the unit-cell volume of reduced ilmenite is significantly larger than that of oxidized ilmenite, whereas their thermoelastic parameters are similar. Our data provide more appropriate input parameters for thermo-chemical models of lunar interior evolution, in which reduced ilmenite plays a critical role

    Antiferromagnetic Phases of One-Dimensional Quarter-Filled Organic Conductors

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    The magnetic structure of antiferromagnetically ordered phases of quasi-one-dimensional organic conductors is studied theoretically at absolute zero based on the mean field approximation to the quarter-filled band with on-site and nearest-neighbor Coulomb interaction. The differences in magnetic properties between the antiferromagnetic phase of (TMTTF)2_2X and the spin density wave phase in (TMTSF)2_2X are seen to be due to a varying degrees of roles played by the on-site Coulomb interaction. The nearest-neighbor Coulomb interaction introduces charge disproportionation, which has the same spatial periodicity as the Wigner crystal, accompanied by a modified antiferromagnetic phase. This is in accordance with the results of experiments on (TMTTF)2_2Br and (TMTTF)2_2SCN. Moreover, the antiferromagnetic phase of (DI-DCNQI)2_2Ag is predicted to have a similar antiferromagnetic spin structure.Comment: 8 pages, LaTeX, 4 figures, uses jpsj.sty, to be published in J. Phys. Soc. Jpn. 66 No. 5 (1997

    Credible and Actionable Evidence Across Stakeholder Levels of the Cooperative Extension System

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    This article provides a look at the various levels within the Cooperative Extension System and the use of evidence within these levels. The authors examine the factors associated with credible evidence and the various levels. The impact of factors such as politics, science, stakeholder support, and expectations are discussed. The various levels within Extension are summarized in relation to evidence that is routinely requested or required for each. Lastly, the authors use information directly from Extension directors to provide a framework for the discussion

    Coexistent State of Charge Density Wave and Spin Density Wave in One-Dimensional Quarter Filled Band Systems under Magnetic Fields

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    We theoretically study how the coexistent state of the charge density wave and the spin density wave in the one-dimensional quarter filled band is enhanced by magnetic fields. We found that when the correlation between electrons is strong the spin density wave state is suppressed under high magnetic fields, whereas the charge density wave state still remains. This will be observed in experiments such as the X-ray measurement.Comment: 7 pages, 15 figure

    Soil conservation II : know your farm.

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    This circular was prepared by O. T. Coleman, Extension Specialist in Soils, in Collaboration with E. T. Itschner, State Club Agent. Acknowledgment is given to A. W. Klemme, Extension Specialist in Soils, for the preparation of Chapter III; to W. R. Tascher, Extension Soil Conservationist, for the preparation of Chapter VI; to John Falloon, Extension Soil Conservationist, for the preparation of Chapter V; and to John Ferguson, Extension Soil Conservationist, for the preparation of Chapter IV. --Page 3."Cooperative Extension Work in Agriculture and Home Economics, University of Missouri, College of Agriculture and the United States Department of Agriculture cooperating.""March, 1939."Title from cover

    Spin-Density-Wave Phase Transitions in Quasi-One-Dimensional Dimerized Quarter-Filled Organic Conductors

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    We have studied spin density wave (SDW) phase transitions in dimerized quarter-filled Hubbard chains weakly coupled via interchain one-particle hopping, tb0t_{b0}. It is shown that there exists a critical value of tb0t_{b0}, tb∗t_{b}^\ast, between the incoherent metal regime (tb0<tb∗t_{b0}<t_{b}^\ast) and the Fermi liquid regime (tb0>tb∗t_{b0}>t_{b}^\ast) in the metallic phase above the SDW transition temperature. By using the 2-loop perturbative renormalization-group approach together with the random-phase-approximation, we propose a SDW phase diagram covering both of the regimes. The SDW phase transition from the incoherent metal phase for tb0<tb∗t_{b0}<t_{b}^\ast is caused by growth of the intrachain electron-electron umklapp scattering toward low temperatures, which is regarded as preformation of the Mott gap. We discuss relevance of the present result to the SDW phase transitions in the quasi-one-dimensional dimerized quarter-filled organic conductors, (TMTTF)2_2X and (TMTSF)2_2X.Comment: 19 pages, 13 eps figures, uses jpsj.sty, corrected typo in the text and figures, no changes to the paper, to appear in J. Phys. Soc. Jpn. 68, No.8 (1999
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