Chemosensory-related gene (CRG) families have been studied extensively in insects, but their evolutionary history across the Arthropoda had remained relatively unexplored. Here, we address current hypotheses and prior conclusions on CRG family evolution using a more comprehensive data set. In particular, odorant receptors were hypothesized to have proliferated during terrestrial colonization by insects (hexapods), but their association with other pancrustacean clades and with independent terrestrial colonizations in other arthropod subphyla have been unclear. We also examine hypotheses on which arthropod CRG family is most ancient. Thus, we reconstructed phylogenies of CRGs, including those from new arthropod genomes and transcriptomes, and mapped CRG gains and losses across arthropod lineages. Our analysis was strengthened by including crustaceans, especially copepods, which reside outside the hexapod/branchiopod clade within the subphylum Pancrustacea. We generated the first high-resolution genome sequence of the copepod Eurytemora affinis and annotated its CRGs. We found odorant receptors and odorant binding proteins present only in hexapods (insects) and absent from all other arthropod lineages, indicating that they are not universal adaptations to land. Gustatory receptors likely represent the oldest chemosensory receptors among CRGs, dating back to the Placozoa. We also clarified and confirmed the evolutionary history of antennal ionotropic receptors across the Arthropoda. All antennal ionotropic receptors in E. affinis were expressed more highly in males than in females, suggestive of an association with male mate-recognition behavior. This study is the most comprehensive comparative analysis to date of CRG family evolution across the largest and most speciose metazoan phylum Arthropoda.

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Nurse leaders and executives should consider measures to improve nurses' sleep quality and enhance nurse productivity. Steps that need to be considered include longer intervals between shift-work cycles, clockwise scheduling order, a longer break time after night shift work, allowing nurses to nap before / during a night shift, and providing a worksite healthy sleep programme.

Purpose: Suicide has been considered a large public health concern in recent years because suicide mortality has been increasing rapidly. This study was done to investigate the prevalence and risk factors of a suicide attempt among adolescents in South Korea. Methods: The data of the 2006 Youth Health Risk Behavior web-based Survey collected by the Korean Center for Disease Control was analyzed using logistic regression for this study. Results: The prevalence of a suicide attempt was 5.2% in South Korea. The risk factors of a suicide attempt were suicidal ideation (odds 31.83), depression (odds 7.98), drug use (odds 4.67), currently smoking (odds 3.19), feeling unhappiness (odds 2.77), stress (odds 2.60), currently drinking alcohol (odds 2.39), sexual activity (odds 2.33), living with neither parent (odds 2.24), initial alcohol drinking by age 9 (odds 1.80), health status (odds 2.15), skipped breakfast (odds 1.75), disease (odds 1.65), and school records (odds 1.22). Conclusion: Suicide screening and prevention programs should be developed, considering these risk factors. Suicide prevention programs should be applied to the at risk population prior to a suicide attempt.

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