Analysis of lifeguard-recorded data at Hanauma Bay, Hawaii.

OBJECTIVE: To describe rescue events at Hanauma Bay using data collected by lifeguards stationed at the bay. METHODS: Lifeguard collected data documenting estimates of daily beach attendance, and characteristics of rescue victims and events were analyzed for the period 2000 to 2007. RESULTS: A total of 4888 Logsheets spanning 2000 to 2007 and 1567 Incident Reports spanning 2000 to 2002 and 2006 to 2007 documenting 1249 rescues were available for analyses. Lifeguard estimates of attendance summing tallies made at 12, 2, and 4 pm overestimated actual attendance by a factor of 1.78 (SD = 0.08) while estimates summing 12 and 4 pm tallies underestimated actual attendance by a factor of 0.91 (SD = 0.04). Both estimates were strongly correlated with actual attendance values (R = 0.98 and R = 0.98, respectively). The average rescue rate for the study period was 7 rescues per 10,000 bathers. Nonresidents accounted for 88% of all visitors to the bay and accounted for a disproportionate percentage of the rescue population (96%, p-value = 0.04). A majority of rescues (63.2%) occurred at a single location called "The Slot." Following rescues, 91.4% of rescue victims were released to the beach, 5.9% were released to their parents or guardians, and 1.4% required transfer to a hospital via ambulance. CONCLUSION: Lifeguard estimates of attendance at Hanauma were precise, and summing 12 and 4 pm attendance tallies provided the most accurate estimate of actual attendance. Rescues at Hanauma Bay occurred predominantly among nonresidents and were concentrated to a single location called "The Slot."

Expression quantitative trait locus mapping of toxoplasma genes reveals multiple mechanisms for strain-specific differences in gene expression.

Toxoplasma gondii is an intracellular parasite with a significant impact on human health, especially in cases where individuals are immunocompromised (e.g., due to human immunodeficiency virus/AIDS). In Europe and North America, only a few clonal genotypes appear to be responsible for the vast majority of Toxoplasma infections, and these clonotypes have been intensely studied to identify strain-specific phenotypes that may play a role in the manifestation of more-severe disease. To identify and genetically map strain-specific differences in gene expression, we have carried out expression quantitative trait locus analysis on Toxoplasma gene expression phenotypes by using spotted cDNA microarrays. This led to the identification of 16 Toxoplasma genes that had significant and mappable strain-specific variation in hybridization intensity. While the analysis should identify both cis- and trans-mapping hybridization profiles, we identified only loci with strain-specific hybridization differences that are most likely due to differences in the locus itself (i.e., cis mapping). Interestingly, a larger number of these cis-mapping genes than would be expected by chance encode either confirmed or predicted secreted proteins, many of which are known to localize to the specialized secretory organelles characteristic of members of the phylum Apicomplexa. For six of the cis-mapping loci, we determined if the strain-specific hybridization differences were due to true transcriptional differences or rather to strain-specific differences in hybridization efficiency because of extreme polymorphism and/or deletion, and we found examples of both scenarios.