Spatial distribution of tree species in a species-rich subtropical mountain forest in central China

Inferring the processes underlying the spatial distribution patterns of tree species is fundamental for understanding species coexistence. Here, we examined spatial distribution patterns of woody plants by using the univariate pair correlation function to quantify spatial patterns of species in a fullly mapped 25 ha subtropical plot in China. We analyzed the relationships between the species attributes and spatial distribution patterns of 137 tree species with at least one individual per hectare. The results showed that aggregated distributions were the dominant pattern for species in the Badagongshan subtropical forests, and that the percentage of significantly aggregated species decreased with increasing spatial scales. Rare species were more aggregated than intermediate and abundant species, but they were more easily influenced by habitat heterogeneity. Also, there was significantly negative relationship between species abundance and species aggregation intensity. The aggregation intensity showed negative relationships to species mean diameter at breast height (DBH) and maximum DBH, i.e., species became more regularly spaced as species stature increased. Species functional traits (e.g., growth form and phenological guild) also had obvious effects on the spatial patterns of species. However, spatial patterns of tree species were not related to the dispersal mode. Our results partially conformed to the prediction that species’ attributes influenced species’ spatial patterns following similar laws, even after controlling for the effects of habitat heterogeneity. Consequently, species attributes (species abundance, mean DBH, maximal DBH, growth form, phenological guild, etc.) and habitat heterogeneity may primarily contribute to spatial patterns and species coexistence in natural forests.

Duration of the Inhibition Effect of Acetylsalicylic Acid on Human Platelet Function

Six useful parameters of the release reaction are measured in 10 human volunteers prior to Aspirin® intake and 1,4,5,6 and 7 days after a single ingestion of 1 gram Aspirin®. These parameters include the intensity of aggregation after 5 min by diluted collagen (ΔE5) and after 10 min by Thrombofax® (ΔE10) and the serotonin-14C release by undiluted and diluted collagen, by Thrombofax® and by bovine plasma.Although a significant inhibition (Wilcoxon signed rank test) is found one day after the Aspirin® ingestion, the duration of the inhibition effect is different according to the test used. The inhibition of the aggregation and serotonin-14C release by Thrombofax® is no longer present on the 4th day. The inhibition effect is found till the 4th day using the serotonin-e14C release by bovine plasma, till the 5th day using the Serotonine-14C release by undiluted collagen and till the 6th day using the aggregation intensity by diluted collagen. The duration of the inhibition is most prolonged (till the 7th day included) if serotonin-14C release by diluted collagen is measured. Individual differences in intensity and duration of the ASA effect on the platelets are noted.In conclusion, the methods for studying the modification of the platelets by acetyl-:salicylic acid are different in sensitivity as to the duration of the inhibition effect after a single oral ingestion. A combination of different tests allows an easier detection of an ASA effect in a single patient.