Steward, Ornellas, Beernink, and Northway (2) reported a 14% error in the placement of intraperitoneal injections of mice. They considered this error inherent in the technique and not simply correctable. We similarly found an error in the intraperitoneal injection of mice and attempted to identify the cause of error by varying such technical procedures as size of needle, site of penetration (through lower left versus lower right quadrant), investigator, angle of needle to the abdominal wall, and speed of injection. None of these technical modifications consistently eliminated or reduced the error of placement.
This article discusses the use of meta-analysis to test theoretical propositions in social psychology. Strategies for identifying theoretically meaningful predictors are considered. Specific techniques for translating hypothesized moderators into operations are then presented. Finally, issues regarding the definition of independent and dependent variables are discussed. Taken together, these strategies and techniques provide a set of tools that enable researchers to take advantage of variability among the results of previous individual studies to develop or test aspects of social psychological theory.
An analysis and optimization of a test to quantitatively assess the resistance of disinfectants to neutralization by organic soil is presented. The recommended method uses sterile, dry baker’s yeast as a standard organic soil, and 24-hr cultures of Staphylococcus aureus and Pseudomonas aeruginosa as test organisms. The test determines the maximum per cent (w/v) of organic soil which a disinfectant can tolerate and remain able to kill about 106 test organisms/ml in 10 min at 25°C. This per cent is defined as the organic soil neutralization number. The procedure offers several advantages over other organic soil capacity tests.
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