ABSTRACT
Unraveling the macroevolutionary history of bryophytes, which arose soon after the origin of land plants but exhibit substantially lower species richness than the more recently derived angiosperms, has been challenged by the scarce fossil record. Here we demonstrate that overall estimates of net species diversification are approximately half those reported in ferns and â¼30% those described for angiosperms. Nevertheless, statistical rate analyses on time-calibrated large-scale phylogenies reveal that mosses and liverworts underwent bursts of diversification since the mid-Mesozoic. The diversification rates further increase in specific lineages towards the Cenozoic to reach, in the most recently derived lineages, values that are comparable to those reported in angiosperms. This suggests that low diversification rates do not fully account for current patterns of bryophyte species richness, and we hypothesize that, as in gymnosperms, the low extant bryophyte species richness also results from massive extinctions.
ABSTRACT
Intra-amniotic infection (IAI) is a common cause of pre-term labour. Manual WBC count on amniotic fluid (AF) has been suggested as a diagnostic test for IAI using a threshold of 50 cells/mm(3). However, no validation studies assessing the accuracy of this method have been performed. AF samples were selected for cell count analysis. WBCs were introduced to 47 AF samples. The results from two technologists' counts were compared with the calculated expected value for WBCs in these samples. Results showed that a comparison between the technologists' WBC count to the expected WBC count yielded R(2) coefficients of 0.62 and 0.78, indicating moderate accuracy. Percentage agreement between the technologists was 67%, indicating low reproducibility. It was concluded that there was moderate correlation between the manual and the expected WBC in the spiked AF samples. Clinicians should be aware of the inaccuracy and imprecision associated with this test when evaluating a patient for IAI.
