Effects of a Web-based food portion training program on food portion estimation.

OBJECTIVE: Assess the effects of a prototype computerized food portion tutorial (CFPT). DESIGN: Participants were randomly assigned to estimate portion sizes for selected food items either prior to or following CFPT training (between groups), and those estimating before CFPT training re-estimated portions after training (within groups). SETTING: Research offices. PARTICIPANTS: Seventy-six adult participants without dietary restrictions. INTERVENTION: The CFPT is a Web-based food portion training program that displays varied portions of 23 food items with user-controllable reference objects and viewing angles. MAIN OUTCOME MEASURES: Estimated vs. weighed portions of food items selected for a meal. ANALYSIS: Nonparametric tests were performed on estimated vs. weighed portion differences and on accuracy ratios between and within groups. RESULTS: A significant difference was found between conditions, both within and between groups, on the discrepancy between estimated and weighed portions for a number of the food items. Training exposure, however, resulted primarily in a shift from underestimation to overestimation, not more accurate estimation. IMPLICATIONS FOR RESEARCH AND PRACTICE: The CFPT produced a significant impact on food portion estimation but appeared to sensitize participants to underestimation errors, leading to overestimation errors. Computerization of food portion training programs holds promise for providing cost-efficient portion estimation training but requires further development and evaluation before being considered for clinical use.

A GAL4-driver line resource for Drosophila neurobiology.

We established a collection of 7,000 transgenic lines of Drosophila melanogaster. Expression of GAL4 in each line is controlled by a different, defined fragment of genomic DNA that serves as a transcriptional enhancer. We used confocal microscopy of dissected nervous systems to determine the expression patterns driven by each fragment in the adult brain and ventral nerve cord. We present image data on 6,650 lines. Using both manual and machine-assisted annotation, we describe the expression patterns in the most useful lines. We illustrate the utility of these data for identifying novel neuronal cell types, revealing brain asymmetry, and describing the nature and extent of neuronal shape stereotypy. The GAL4 lines allow expression of exogenous genes in distinct, small subsets of the adult nervous system. The set of DNA fragments, each driving a documented expression pattern, will facilitate the generation of additional constructs for manipulating neuronal function.