沙溪水污染对微生物群落变化的影响

沙溪是闽江上游3大支流之一.近年来,随着三明市经济的发展,局部污染事件仍时有发生.对沙溪三明河段的细菌、真菌、大肠菌群以及降解污染物的主要微生物进行了数量跟踪,结合COD、总氮和总磷等污染物对沙溪水环境与微生物群落变化的关系进行了初步的研究.结果表明:各种微生物的数量变化与主要的有机污染物值之间存在显著的相关性,所有的相关系数均大于0.7,表明微生物在降解与净化中起着重要的作用,同时对水环境的污染状况具有一定的指示作用;降解有机物的主要微生物的数量于COD显著相关,可作为该河段有机污染物水平的指标;研究结果还显示,三化总口和三农电化口是主要的有机污染点,应加强对这两个位点的监测和排污管理

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^