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Background: Athletic performance consists of attributes including: technique, strength, power, and endurance. There are many training methods designed to optimize athletic performance. High-intensi...

BACKGROUND: Clinicians frequently assess the accommodative convergence to accommodation (AC/A) ratio using near phoria measurements and accommodative stimuli. The purpose of this study was to evaluate the repeatability of AC/A ratio measurements and to compare the response AC/A ratio to stimulus AC/A ratios determined two different ways. METHODS: Heterophorias and accommodative responses to different stimuli were measured simultaneously on eight subjects at two visits. A Canon Auto Ref R-1 autorefractor was used to measure accommodative response, while vergence posture was measured using the modified Thorington heterophoria technique. These results were used to calculate response-slope, stimulus-slope and stimulus-gradient AC/A ratios and the means of these ratios for each session were compared. Correlations between the response AC/A ratios and the stimulus AC/A ratios were calculated. RESULTS: The mean response AC/A ratios for the two sessions were 3.8 prism dioptres per dioptre for each session. The correlation between the slope-determined ratios was 0.56, and between the response-slope and the stimulus-gradient AC/A ratios the correlation was -0.03. The regression equation for the slope-determined AC/A ratios was calculated. CONCLUSIONS: Means for the two sessions were not significantly different for any of the AC/A ratios. The response-slope and stimulus-slope AC/A ratios had a moderately significant correlation and a predictive regression equation was determined. The stimulus-gradient AC/A ratios were not correlated with the response-slope AC/A ratios.

Background: Comparative analysis of RNA sequences is the basis for the detailed and accurate predictions of RNA structure and the determination of phylogenetic relationships for organisms that span the entire phylogenetic tree. Underlying these accomplishments are very large, wellorganized, and processed collections of RNA sequences. This data, starting with the sequences organized into a database management system and aligned to reveal their higher-order structure, and patterns of conservation and variation for organisms that span the phylogenetic tree, has been collected and analyzed. This type of information can be fundamental for and have an influence on the study of phylogenetic relationships, RNA structure, and the melding of these two fields. Results: We have prepared a large web site that disseminates our comparative sequence and structure models and data. The four major types of comparative information and systems available for the three ribosomal RNAs (5S, 16S, and 23S rRNA), transfer RNA (tRNA), and two of the catalytic intron RNAs (group I and group II) are: (1) Current Comparative Structure Models; (2) Nucleotide Frequency and Conservation Information; (3) Sequence and Structure Data; and (4) Data Access Systems. Conclusions: This online RNA sequence and structure information, the result of extensive analysis, interpretation, data collection, and computer program and web development, is accessible at our Comparative RNA Web (CRW) Site [http://www.rna.icmb.utexas.edu] . In the future, more data and information will be added to these existing categories, new categories will be developed, and additional RNAs will be studied and presented at the CRW Site.