This paper discusses the irreversible decrement model and explores credibility and performance changes in older persons through a study conducted with 300 residents of the Dallas/Fort Worth area. Phyllis L. Jones performs a literature review before delving into the methodology, process, and results of the study.

The determination of level populations and detailed population mechanisms in dense plasmas has become an increasingly important problem in atomic physics. In this work, the density variation of line intensities and level populations in aluminum K-shell and molybdenum and silver L-shell emission spectra have been measured from high-powered, laser-produced plasmas. For each case, the density dependence of the observed line emission is due to the effect of high frequency electron-ion collisions on metastable levels. The density dependent line intensities vary greatly in laser-produced plasmas and can be used to extract detailed information concerning the population kinetics and level populations of the ions. The laser-plasmas had to be fully characterized in order to clearly compare the observed density dependence with atomic theory predictions. This has been achieved through the combined use of new diagnostic instruments and microdot targets which provided simultaneously space, time, and spectrally resolved data. The plasma temperatures were determined from the slope of the hydrogen-like recombination continuum. The time resolved electron density profiles were measured using multiple frame holographic interferometry. Thus, the density dependence of K-shell spectral lines could be clearly examined, independent of assumptions concerning the dynamics of the plasma. In aluminum, the electron density dependence of …

The morphology of zinc as it is electrodeposited from acid solutions demonstrates a remarkable imprint of electrolyte flow conditions. The development of macromorphology of zinc deposits has been investigated under galvanostatic conditions on a rotating plantinum disk electrode by use of photomacrography, scanning electron microscopy, electron probe microanalysis and Auger microprobe analysis. Logarithmic spiral markings, which reflect the hydrodynamic flow on a rotating disk, appear in a certain region of current density well below the limiting current density. Morphological observations revealed the major influence of trace lead ions on the amplifications of surface roughness through coalescence and preferred growth of initial protrusions. Results obtained from ultra-pure electrolyte suggest preferred crystal growth towards well-mixed orientation in the concentration field caused by slight differences in crystallization overpotential. A qualitative model involving a coupling mechanism between the evolving surface roughness and instability phenomena in the boundary layer is advanced to explain the formation of spiral patterns.

Results are reported from a streamer chamber experiment performed at Stanford Linear Accelerator Center (SLAC) to study the production of the phi (1020) in OZI-allowed and forbidden processes in ..pi../sup +/p interactions at 16 GeV/c. Production properties of the anti K*/sup ./(896) are also studied and discussed.

Gamma rays associated with psi mesons have been studied in 225 GeV/c ..pi../sup -/Be interactions. The psi-..gamma.. mass spectrum shows an excess of 47 +- 11 events above background centered at 3.531 GeV/c/sup 2/ with an rms width of 22.4 MeV. Attributing this excess of events to the decay chi ..-->.. psi ..gamma.. implies that 38 +- 9 % of all psi mesons are produced by this mechanism. The experimental setup and results are detailed.

A study of the forms of trace elements occurring in Solvent Refined Coal has been performed by chemical separation of the Solvent Refined Coal based on differences in the functionality and molecular weight of the organic matrix. Analysis of the fractions separated for various trace elements has revealed associations of certain elements with other elements as well as with certain fractions. The analysis of Solvent Refined Coal I by these methods provided data on the distribution of Ti, V, Ca, S, Al, Mn, As, Se, Cr, Fe, Ni, Zn, Sc, and Ga in the fractions generated. Because of the low trace element content of Solvent Refined Coal II only As, Se, and Cr could be detected in the silica fractions. Based on the distributions three different groups of elements have been based on the association of elements with each other and with certain fractions. The first group is composed of As, Se, and Cr associated with silica fractions of relatively low functionality; these elements have a high percent solubility in the starting Solvent Refined Coal II oil. The second group composed of Ti, V, and to a lesser extent a second form of Cr, is associated with fractions that have …

The spectra of Sc I, Sc II, Sc III, and Sc IV are analyzed through the use of the Zeeman effect. A sliding spark of the author's design is used in conjunction with a 27 kilogauss electromagnet. The spectra have (reciprocal) dispersions of 0.2 to 0.5 A/mm. 10 Sc I levels, 16 Sc II levels and 5 Sc III levels show Zeeman splitting. No Sc IV Zeeman patterns were observed. 2 Sc I, 4 Sc II, and all of the Sc III level data are new.