Upright crinoids of the Thornton Reef,Wenlock (Silurian) of Illinois,USA

The rare preservation of columns perpendicular to bedding may provide convincing evidence that ancient crinoids adopted an upright attitude during life. However, taphonomic and sedimentological analyses are important in determining whether such occurrences are truly in situ or represent unusual allochthonous accumulations. The Crinoid Biosome of the Thornton Reef Complex, Silurian of Illinois, USA, includes pluricolumnals preserved perpendicular to bedding, in association with more common specimens parallel or angled to bedding. Upright pluricolumnals are relatively shorter (<150 mm) than the longest non-upright specimens; they sometimes occur as imbricate accumulations and lack attachment structures (although these are preserved separately). Brachiopod valves and colonial corals may also be preserved perpendicular to bedding. These features suggest that the Thornton beds were formed as viscous mass flow deposits and that the upright crinoid columns are allochthonous or, at best, parautochthonous. © 1996 John Wiley & Sons, Ltd.     

3D near-surface soil response from H/V ambient-noise ratios

The applicability of the horizontal-to-vertical (H/V) ambient-noise spectral ratio for characterizing earthquake site effects caused by near-surface topography and velocity structures was evaluated at sites underlain by thick (i.e. >100 m) sediment deposits near the southern-end of the New Madrid seismic zone in the central United States. Three-component ambient-noise and velocity models derived from seismic (shear-wave) refraction/reflection surveys showed that a relatively horizontal, sharp shear-wave velocity interface in the soil column resulted in an H/V spectral ratio with a single well-defined peak. Observations at sites with more than one sharp shear-wave velocity contrast and horizontally arranged soil layers resulted in at least two well-defined H/V spectral ratio peaks. Furthermore, at sites where there were sharp shear-wave velocity contrasts in nonhorizontal, near-surface soil layers, the H/V spectra exhibited a broad-bandwidth, relatively low-amplitude signal instead of a single well-defined peak.     

The solubility of aragonite in seawater—I. Effect of pH and water chemistry at one atmosphere

The effect of water chemistry on the solubility of aragonite in seawater has been defined experimentally as a series of apparent solubility products measured with respect to pH at one atmosphere.The dominant control of the apparent solubility product of aragonite is the carbonate ion concentration, and this is primarily a function of pH. In the light of this fact, we have reconciled our data with 81 other reported values of aragonite solubility by simply examining the water chemistry of the waters in which they were determined.     

Integrating GB and US census microdata for studying the impact of family migration on partnered women's labour market status

This paper investigates the problems in integrating different data sets for social science research. A cross-national analysis of the effects of family migration on labor market participation rates for female partners was used as an example to concretize these problems. The data used in the cross national analysis came from the 1991 British Census Sample of Anonymised Records and the 1990 United States Public Use Microdata Sample. The problems addressed were the following: data collection; manipulation and reliability; question type and definition; and measurement of individual and family variables. As part of the analysis, some empirical findings were also presented. Significant overall differences between the US and Great Britain (GB) samples were observed, particularly concerning graduate qualifications, marital and employment status, and ethnic group. There were higher numbers of married partners and full-time workers in the US sample, while female partners undertaking part-time employment were greater in GB. Furthermore, the US sample had more couples with a female graduate as compared with the GB sample who had a higher proportion of nongraduate couples. Finally, this paper recognized the importance of cross- national research in the evaluation of national ideological and institutional structures.     

Updates to the MSFC Meteoroid Stream Model

The Marshall Space Flight Center (MSFC) Meteoroid Stream Model simulates particle ejection and subsequent evolution from comets in order to provide meteor shower forecasts to spacecraft operators for hazard mitigation and planning purposes. The model, previously detailed in Moser and Cooke (Earth Moon Planets 95, 141 (2004)), has recently been updated; the changes include the implementation of the RADAU integrator, an improved planetary treatment, and the inclusion of general relativistic effects in the force function. The results of these updates are investigated with respect to various meteoroid streams and the outcome presented.