Quality assurance aspects of an environmental fate study

Environmental fate studies pose a challenge to the quality assurance officer due to the dynamic nature of the methodology. Protocols must be carefully constructed so that the study is conducted within GLP guidelines and is acceptable to the agency to which it is to be submitted. These protocols must also be flexible enough to adapt to methodologies that might evolve during the study. This flexibility requires careful auditing to assure adherence to the protocol and methods as they are developed. These ideas will be highlighted in a general discussion of the many aspects of environmental fate quality assurance.

The use of itemized register tapes for analysis of household food acquisition patterns prompted by children

This article describes a method of collecting and analyzing itemized grocery receipts for use in epidemiological studies. As part of a larger study of children's food acquisition and exercise habits related to cardiovascular disease, a sample of 50 families was asked to keep itemized grocery receipts for a 2-week period. To control for bias as a result of differences in food consumption and food acquisition, mothers were asked to log meals eaten away from home, food used from home production, and gifts of foods. Items on the receipts were coded according to food groups and whether they represented child-prompted purchases. The items were expressed in terms of the percentage of the food dollar each category represented. Data from the survey were compared with data collected in national surveys. The method was found to be relatively non-intrusive, easily carried out, and eliminated many of the problems associated with non-response, respondent burden, and recall characteristic of other food account methods. It is suggested as a feasible way of characterizing the family food environment in epidemiological studies.

Mariner 9 Television Reconnaissance of Mars and Its Satellites: Preliminary Results

At orbit insertion on 14 November 1971 the Martian surface was largely obscured by a dust haze with an extinction optical depth that ranged from near unity in the south polar region to probably greater than 2 over most of the planet. The only features clearly visible were the south polar cap, one dark, spot in Nix Olympica, and three dark spots in the Tharsis region. During the third week the atmosphere began to clear and surface visibility improved, but contrasts remained a fraction of their normal value. Each of the dark spots that apparently protrude through most of the dust-filled atmosphere has a crater or crater complex in its center. The craters are rimless and have featureless floors that, in the crater complexes, are at different levels. The largest crater within the southernmost spot is approximately 100 kilometers wide. The craters apparently were formed by subsidence and resemble terrestrial calderas. The south polar cap has a regular margin, suggsting very flat topography. Two craters outside the cap have frost on their floors; an apparent crater rim within the cap is frost free, indicating preferentia loss of frost from elevated ground. If this is so then the curvilinear streaks, which were frost covered in 1969 and are now clear of frost, may be low-relief ridges. Closeup pictures of Phobos and Deimos show that Phobos is about 25 +/-5 by 21 +/-1 kilometers and Deimos is about 13.5 +/- 2 by 12.0 +/-0.5 kilometers. Both have irregular shapes and are highly cratered, with some craters showing raised rims. The satellites are dark objects with geometric albedos of 0.05.