Word associations of 80 young and 80 older adults were compared for 113 stimulus words. The proportion of paradigmatic responses varied with the grammatical class of the stimulus word and with the vocabulary level of the subject, but not with age. The same proportion of young and older adults gave the most common responses. Although older adults had a greater number of unique responses, this seems to reflect age differences in vocabulary level, as vocabulary but not age was a good predictor. Within-subject variability was also comparable across age, as on a retest young and older adults gave the same proportion of responses that were identical to those on the original test. Both age groups were more likely to repeat common than uncommon responses on the retest. This, together with analyses of response latency, suggests equivalent use of strategic processes across age. The results indicate that semantic structure and semantic encoding in adults are related to verbal ability, but not to age.

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The environmental characterization of building interiors and other surfaces has generally been performed with wipe-sampling because it is a non-destructive technique. There is no consensus, however, as to the interpretation of the results of wipe-sampling. Specifically, there is not a standardized method to determine if chemicals found at sampled levels pose a threat to human health. A methodology was developed, based on acceptable health risk levels, to derive screening levels for evaluating wipe-sampling results pertaining to industrial scenarios. The methodology was based on the United States Environmental Protection Agency (USEPA) Region IX Preliminary Remediation Goal (PRG) approach; a multi-exposure methodology commonly used for evaluating soil concentrations. PRGs are the USEPA determined health based goals for soil preliminary remediation efforts. Probabilistic techniques were used to conduct a sensitivity analysis of the methodology to determine which variables drive the ultimate screening levels. Discrete values were then selected based on standard industrial scenarios common to the US Army. The wipe surface screening levels reported are for use as preliminary guidelines which help to determine whether further sampling or cleanup are necessary. The levels are not meant as cleanup or compliance criteria. ᮊ

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