Precipitation is the main axis of tropical plant phylogenetic turnover across space and time.

This is the final version. Available from the American Association for the Advancement of Science via the DOI in this record. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. All phylogenies, both occurrence datasets, and the taxonomic checklist are available as data S1 on Zenodo (https://doi.org/10.5281/zenodo.7568716). GenBank or European Nucleotide Archive accession codes for new genetic sequences generated here are listed in tables S1 and S4 to S10.Early natural historians-Comte de Buffon, von Humboldt, and De Candolle-established environment and geography as two principal axes determining the distribution of groups of organisms, laying the foundations for biogeography over the subsequent 200 years, yet the relative importance of these two axes remains unresolved. Leveraging phylogenomic and global species distribution data for Mimosoid legumes, a pantropical plant clade of c. 3500 species, we show that the water availability gradient from deserts to rain forests dictates turnover of lineages within continents across the tropics. We demonstrate that 95% of speciation occurs within a precipitation niche, showing profound phylogenetic niche conservatism, and that lineage turnover boundaries coincide with isohyets of precipitation. We reveal similar patterns on different continents, implying that evolution and dispersal follow universal processes.Natural Environment Research Council (NERC)Swiss National Science Foundation (SNSF)Swiss National Science Foundation (SNSF)Swiss National Science Foundation (SNSF)Claraz Schenkung Foundation, SwitzerlandU.S. National Science FoundationU.S. National Science FoundationNatural Sciences and Engineering Research Council of Canada (NSERC)Biotechnology and Biological Sciences Research CouncilFAPESB, BrazilFAPESB, BrazilFAPESB, BrazilCNPq, BrazilCNPq, BrazilCNPq, BrazilCNPq, BrazilConsejo Nacional de Investigaciones Científicas y Técnicas (CONICET), ArgentinaAgencia Nacional de Promoción Científica y Tecnológica (ANPCyT), ArgentinaInstituto Nacional de Tecnología Agropecuaria (INTA), ArgentinaInstituto Nacional de Tecnología Agropecuaria (INTA), ArgentinaUniversidad de Morón, ArgentinaCoordination for the Improvement of Higher Education Personnel (CAPES), BrazilEmbrapa Recursos Genéticos e Biotecnologia (CENARGEN), Brazi

Effect of different frequencies of fluoride dentifrice and mouthrinse administration: an in situ study

The effect of a combination of topical fluoridation methods for inhibition of enamel demineralization in the face of a cariogenic challenge has not been clearly established. This in situ crossover study aimed to assess whether the addition of daily use of fluoride mouthrinse (FR) to that of fluoride dentifrice (FD) is equivalent to increasing the frequency of FD application in terms of the effect on enamel demineralization and fluoride content. Over 3 phases of 14 days each, 12 volunteers wore appliances containing enamel blocks exposed to a 20 % sucrose solution 8 times/day. During each phase the blocks underwent one of the following treatments: 2x/day FD, 2x/day FD + 1x/day FR, and 3x/day FD. The blocks were assessed for hardness and fluoride content. Three x/day FD did not differ from 2x/day + 1x/day FR, however it enhanced demineralization protection when compared to 2x/day FD. All treatments produced an increase in enamel fluoride content compared to no treatment (sound blocks) (p < 0.05), but the differences between them were not significant. The results of this study suggest that the daily use of fluoride mouthrinse combined with that of fluoride dentifrice has similar effects on enamel demineralization and fluoride content when compared to increasing the frequency of fluoride dentifrice use