Carbon-14 dating and percent CaC03 in late Pleistocene sediments suggest that deepsea sedimentation rates vary cyclically and that this cyclicity is related to climate. Sedimentation rate variability leads to nonlinearity in the time-depth mapping function. This nonlinearity can have profound affects on signal spectra, leading to the development of harmonics and intermodulation tones. These distortion effects in the spectra give a direct indication of the degree of nonlinearity, thereby providing a tool for realigning time and depth scales. A tuning technique is developed which assumes a direct link between climate (as measured in 6180 from planktonic foraminifer tests) and sedimentation rates. A criterion of "spectral simplicity," as quantified in the varimax norm, is used to demodulate the input spectrum. Application of this technique to anequatorial Pacific piston core (ERDC 84) found peak glacial sedimentation rates to be 30% higher than peak interglacial rates, a figure in good agreement with l•C-based estimates from the same area. This technique is compatible with other time scale tuning techniques such as those using orbital parameters and, in combination with these other techniques, provides a method for fine-tuning any late Pleistocene record.
Development of objective measurements is an important requirement for establishing performance-based standards for protective clothing used while handling pesticide. This study, the second in a two-part series, reports on the work completed to evaluate the performance of approximately 100 fabrics that are either used or have the potential to be used for garments worn by operators while applying pesticides. Part I, published separately, provides an overview of these issues and describes research undertaken to select a test chemical for use in subsequent studies. The goals of this study were first to develop a comprehensive approach to evaluate the performance of garments currently being used by pesticide operators, and second, to use the laboratory and field data in the development of performance specifications.
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