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N M Burns

Publications and source records attributed to N M Burns.

3 recordsLinked to original sources

Early understanding of the representational function of pictures.

An important function of pictures is the communication of information--a function that has been ignored in research on the development of pictorial perception and comprehension. When are young children first capable of using pictures as a source of information to guide their behavior? The six studies reported here reveal a dramatic developmental change between 24 and 30 months of age in the use of pictorial information about the location of a hidden object. When presented with a picture that showed the location of a hidden toy, 30-month-olds readily retrieved the toy, but 24-month-olds did not. The extremely poor performance of the 24-month-olds was replicated and shown to persist in spite of various modifications made in the task in an effort to improve performance. We conclude that our 24-month-old subjects did not interpret the pictures as representations of current reality. We propose that very young children's early pictorial experience may predispose them to be overly conservative in interpreting the relation between pictures and their referents.

Age Factors↗

Headspace gas chromatographic method for determination of methyl bromide in food ingredients.

A headspace gas chromatographic (GC) method, which can be automated, has been developed for determination of methyl bromide. This method has been applied to wheat, flour, cocoa, and peanuts. Samples to be analyzed are placed in headspace sample vials, water is added, and the vials are sealed with Teflon-lined septa. After an appropriate equilibration time at 32 degrees C, the samples are analyzed within 10 h. A sample of the headspace is withdrawn and analyzed on a gas chromatograph equipped with an electron capture detector (ECD). Methyl bromide levels were quantitated by comparison of peak area with a standard. The standard was generated by adding a known amount of methyl bromide to a portion of the matrix being analyzed and which was known to be methyl bromide free. The detection limit of the method was 0.4 ppb. The coefficient of variation (CV) was 6.5% for wheat, 8.3% for flour, 3.3% for cocoa, and 11.6% for peanuts.

Arachis↗