Summary of an integrated ERTS-1 project and its results at the Missouri Geological Survey

Use of the ERTS imagery involved the recognition and interpretation of various ground patterns. Analysis and application are tied to ongoing programs. Specific studies utilizing the imagery and NASA aircraft photography are: a statewide lake and dam inventory; assessment of flooding and floodprone areas along the Missouri portion of the Mississippi and Missouri Rivers; land-use classification for several counties; structural features in selected areas; and Pleistocene features in northern Missouri. Though it has been suggested that repetitive coverage is not necessary for geologic studies, it is this specific feature along with the synoptic view of large portions of the State that provided the potential for the utilization of the ERTS imagery in Missouri. Other State agencies, Departments of Conservation, Agriculture, and Community Affairs, have expressed interest in the potential application of ERTS data in their respective fields

Electron-phonon interaction dressed by electronic correlations near charge ordering as the origin for superconductivity in cobaltates

We consider possible routes to superconductivity in hydrated cobaltates Na_xCoO_2.yH_2O on the basis of the t-J-V model plus phonons on the triangular lattice. We studied the stability conditions for the homogeneous Fermi liquid (HFL) phase against different broken symmetry phases. Besides the sqrt(3)xsqrt(3)-CDW phase, triggered by the nearest-neighbour Coulomb interaction V, we have found that the HFL is unstable, at very low doping, against a bond-ordered phase due to J. We also discuss the occurrence of phase separation at low doping and V. The interplay between the electron-phonon interaction and correlations near the sqrt(3)xsqrt(3)-CDW leads to superconductivity in the unconventional next-nearest neighbour f-wave (NNN-f) channel with a dome shape for Tc around x ~ 0.35, and with values of a few Kelvin as seen in experiments. Near the bond-ordered phase at low doping we found tendencies to superconductivity with d-wave symmetry for finite J and x<0.15. Contact with experiments is given along the paper.Comment: 21 pages, 6 figure

Hard x-ray spectroscopy in NaxCoO2 and superconducting NaxCoO2 - yH2O: A view on the bulk Co electronic properties

The electronic properties of Co in bulk Na0.7CoO2 and the superconducting hydrated compound Na0.35CoO2 - y H2O have been investigated by x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) using hard x-rays. The XAS spectra at the Co K-edge were measured in both compounds with two different polarization directions. The changes in the XAS spectra upon hydration and their polarization dependence are well accounted for by linear muffin- tin orbital calculations in the local density approximation. The underlying electronic structure indicates the strong hybridization between the Co 3d and O 2p states in both compounds, while the electron localization is enhanced in the hydrated compound due to the increase of the Co-Co interplanar distance. The Co K pre-edge further highlights the splitting of the d band as a result of the crystal field effect and demonstrates the Co valency increase when Na0.7CoO2 is hydrated. The RIXS spectra measured at the Co K-edge show an energy loss feature around 10 eV in both compounds in fair agreement with the calculated dynamical structure factor. The RIXS feature is associated to a damped plasmon excitation.Comment: 8 page

Studying Within-Person Changes in Work Motivation in the Short and Medium- Term: You Will Likely Need More Measurement Points than You Think!

En el estudio de la motivación laboral, el análisis intrapersona de datos provenientes de diseños longitudinales es hoy común en el área. Sin embargo, algunas características del diseño de investigación empleado pueden estar influyendo en la variabilidad intrapersona encontrada. En este trabajo analizamos cómo influye el número de medidas repetidas por participante en la varianza intrapersona de la motivación laboral. Mediante dos estudios (una revisión sistemática y un estudio empírico original) mostramos cómo el número de medidas repetidas influye significativamente en la varianza intrapersona encontrada, que llega a alcanzar valores máximos del 52%-54% sobre el total de la varianza. Para llegar a esos valores de varianza explicada en el caso de la motivación laboral se necesitarían un mínimo de 25-30 medidas repetidas para ser rigurosos en la medida de la varianza intraperson