Methodological considerations when conducting direct observation in an outdoor environment: our experience in local parks.

OBJECTIVE: This paper discusses some of the inherent methodological limitations of gathering data via direct observation using local parks as a case study. METHODS: Direct observation was carried out in five parks on seven non-consecutive days in 1998 and on matched days in 1999. Information recorded for each person included the time of park entry and exit, gender, age group, and activity/ies undertaken while in the park. METHODOLOGICAL CONSIDERATIONS: The location of the observation point, observer reliability, recording and accuracy of data, and specific issues related to outdoor observation areas should all be considered when designing a study incorporating direct observation as a data collection method. CONCLUSIONS: Direct observation can provide valuable information. However, pilot testing is essential for minimising potential problems associated with this method and optimising data quality. IMPLICATIONS: The issues discussed in this paper provide a useful guide for other researchers undertaking direct observation in outdoor environments.

Isolation, identification, and enantioselective synthesis of octane-1,3,7-triol: determination of its absolute configuration

Extracts obtained by solid-phase extraction from apples were separated by multilayer countercurrent chromatography. In the most polar fractions, the novel octane-1,3,7-triol was identified by 1H and 13C NMR as well as LC-MS and by comparison with the synthesized racemic reference compound. Resolution of the enantiomers was achieved after acetylation of the triol followed by GC separation. The enantioselective synthesis of the stereoisomers of octane-1,3, 7-triol was performed using the building blocks (R)- and (R, S)-butane-1,3-diol and (S)- and (R,S)-butane-1,2,4-triol. Comparison with the isolated products indicated that the natural compound consisted of a mixture of (3R,7S)- and (3R,7R)-octane-1,3,7-triol in a ratio of 2:3. Since the C3 chiral center is enantiomerically pure, the triol might be biogenetically related to the known antimicrobial (R)-(+)-octane-1,3-diol, the major volatile compound of some apple cultivars.