Search

Net primary production (NPP) is a central and fundamental carbon-related term in global change studies. We proposed a top-down method to quantifying forest NPP which overcomes the deficits of the traditional bottom-up method. The new top-down method combines eddy flux data, climate variables, tree inventory and metabolic theory. Our method was tested in six forests and provides reliable annual NPP estimations which are consistent with bottom-up results. Carbon use efficiency also supports this new method. Taking advantage of fine temporal resolution of our top-down method, we examined whether and confirmed NPP was well correlated with leaf area index at a seasonal scale, as suggested by past studies. The potential value of our new method as a standard NPP method is high because of the world-wide network on eddy tower and inventory plot, however further data of performance of the new method is needed to fully evaluate its performance under different conditions.

OBJECTIVE: To evaluate the vaccine effectiveness (VE) of mRNA COVID-19 vaccines in children using a meta-analysis approach. MATERIALS AND METHODS: Relevant studies on the use of mRNA COVID-19 vaccines in children were identified through computerized searches. VE-related indicators were extracted, and data analysis was performed using the R software with the meta-package. RESULTS: This study included a total of 12 relevant articles involving 9,963,732 participants from multiple centers in different countries, including the United States, Canada, Singapore, Israel, South Korea, and Qatar. The administered vaccine types included BNT162b2 and mRNA-1273. Participants were categorized into partially immunized (one dose of vaccine) and fully immunized (two doses of vaccine). Four articles reported VE after one dose of vaccine, while 12 reported VE after two doses. Heterogeneity analysis indicated significant heterogeneity among the studies, warranting the use of a random-effects model for analysis. Meta-analysis results revealed that the VE of partial immunization ranged from 16.61 (95% CI: 6.32-25.77) to 34.30 (95% CI: 24.21-43.04), with a pooled VE of 22.80 (95% CI: 15.68-29.32). The VE after full immunization ranged from 16.14 (95% CI: 14.42-17.83) to 90.47 (95% CI: 67.42-97.21), with a pooled VE of 56.17 (95% CI: 41.12-67.37). Meta-regression analysis showed no statistically significant correlation between VE and time (p>0.05). CONCLUSIONS: Both partial and full immunization of the BNT162b2 mRNA vaccine provide benefits in reducing infection rates. VE varies over time and is closely associated with viral mutations and waning immunity. The specific mechanisms require further investigation. [ABSTRACT FROM AUTHOR]