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We report hard x-ray photoemission spectroscopy measurements of the electronic structure of the prototypical correlated oxide ${\mathrm{Sr}}_{x}{\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{VO}}_{3}$. By comparing spectra recorded at different excitation energies, we show that 2.2 keV photoelectrons contain a substantial surface component, whereas 4.2 keV photoelectrons originate essentially from the bulk of the sample. Bulk-sensitive measurements of the O $2p$ valence band are found to be in good agreement with ab initio calculations of the electronic structure, with some modest adjustments to the orbital-dependent photoionization cross sections. The evolution of the O $2p$ electronic structure as a function of the Sr content is dominated by $A$-site hybridization. Near the Fermi level, the correlated V $3d$ Hubbard bands are found to evolve in both binding energy and spectral weight as a function of distance from the vacuum interface, revealing higher correlation at the surface than in the bulk.

An x‐ray beam position monitor has been developed and is currently operational at the NIST beam line X‐24A of the National Synchrotron Light Source. It was developed to accurately measure the vertical position of the synchrotron beam and to allow precise positioning of beam line optics. It is an area‐type monitor positioned 5.6 m from the tangent point and precedes all beam line instrumentation. Vertical beam position is given by the differential photoemission current from two grids mounted on a Macor frame. The monitor also senses the total photon beam flux.

A new ‘‘Cowan type’’ double‐crystal monochromator, based on the boomerang design used at National Synchrotron Light Source (NSLS) beamline X‐24A, has been developed for beamline 9.3.1 at the Advanced Light Source (ALS), a windowless ultrahigh vacuum beamline covering the 1–6 keV photon‐energy range. Beamline 9.3.1 is designed to simultaneously achieve the goals of high energy resolution, high flux, and high brightness at the sample. The mechanical design of the monochromator has been simplified, and recent developments in technology have been included. Measured mechanical precision of the monochromator shows significant improvement over existing designs. In tests with x‐rays at NSLS beamline X‐23A2, maximum deviations in the intensity of monochromatic light were just 7% during scans of several hundred eV in the vicinity of the Cr K edge (6 keV) with the monochromator operating without intensity feedback. Such precision is essential because of the high brightness of the ALS radiation and the overall length of beamline 9.3.1 (26 m).

A new ``Cowan type`` double-crystal monochromator, based on the boomerang design used at NSLS beamline X-24A, has been developed for beamline 9.3.1 at the ALS, a windowless UHV beamline covering the 1-6 keV photon-energy range. Beamline 9.3.1 is designed to simultaneously achieve the goals of high energy resolution, high flux, and high brightness at the sample. The mechanical design has been simplified, and recent developments in technology have been included. Measured mechanical precision of the monochromator shows significant improvement over existing designs. In tests with x-rays at NSLS beamline X-A, maximum deviations in the intensity of monochromatic light were just 7% during scans of several hundred eV in the vicinity of the Cr K edge (6 keV) with the monochromator operating without intensity feedback. Such precision is essential because of the high brightness of the ALS radiation and the overall length of beamline 9.3.1 (26 m).

Multilayer-coated mirrors, rather than conventional total-reflection mirrors, have been proposed as a means to reduce power incident on the first optical element of high resolution monochromators. We have designed, fabricated, installed and characterized a multilayer pre-mirror specifically for the 800 to 4000 eV range for the X24-A bending magnet beamline at the National Synchrotron Light Source. Various aspects of this application are discussed, including power and thermal considerations, beamline layout considerations and constraints, choice of multilayer materials and substrate, and techniques to ensure lateral uniformity of the multilayer. Results of a preliminary characterization of a mirror coated with a SiC/V multilayer and installed in the beamline are also discussed. 9 refs., 5 figs.

The Medical Illness Severity Grouping System--called MEDISGRPS--is an admission-oriented patient severity grouping system that uses objective, key clinical findings to place patients in one of five severity groupings. Data from five hospitals indicate that severity level at admission is an important predictor of resource use, is essential for analysis of patients who deteriorate and/or respond poorly to therapy, and is useful to further specify DRGs. Measures of effectiveness and efficiency using MEDISGRPS are suggested.

X-ray standing wave (XSW), x-ray diffraction, and photoluminescence (PL) measurements were used to assess the layer perfection and positions of 1 and 1/2 monolayer (ML) InAs quantum wells buried in GaAs(001). Local structure in the 1-ML films was evaluated using x-ray absorption fine structure (XAFS) measurements. Growth temperature effects were studied in a series of samples produced by metal organic vapor phase epitaxy (MOVPE) between 400 and $600\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}.$ The XSW coherent position of the In atoms decreases with increasing temperature in the 1-ML samples, and the optimal growth temperature is near $550\ifmmode^\circ\else\textdegree\fi{}\mathrm{C},$ as evidenced by the coherent position of $1.15\ifmmode\pm\else\textpm\fi{}0.02$ and the relatively high coherent fraction of $0.72\ifmmode\pm\else\textpm\fi{}0.08.$ With decreasing growth temperature the XSW measurements may suggest segregation of In atoms, which results in an incorporation of the In into multiple layers. The segregation appears to be reduced at the higher temperatures due to the favorable kinetic conditions created in the MOVPE environment. Low-temperature PL measurements indicate that the sharpest and most intense In-excitonic emission is obtained from the 1-ML sample grown at $530\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}.$ For the $\frac{1}{2}$-ML samples, growth temperatures of 400 and $600\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ produce similar standing wave results, although the PL reveals the higher temperature sample to be of far superior quality, due to excessive carbon incorporation at $400\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}.$ In-As bond-length distortions found in the XAFS measurements agree with a macroscopic elastic description of the pseudomorphic epitaxy.