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541.
受前体物排放和气象条件等因素共同驱动,大气臭氧(O3)已成为影响城市夏季环境空气质量的主要污染物.目前物理化学机制驱动的演绎模型在进行O3污染解析时需要的模型参数众多,运算时效性较差;数据驱动的归纳模型运算效率高,但存在可解释性差等问题.通过建立可解释性数据驱动的Correlation-ML-SHAP模型,Correlation模块挖掘O3浓度关联影响因素,机器学习ML模块耦合可解释性SHAP模块计算各驱动因素对O3浓度的影响贡献,实现对驱动因素的定量解析,并以晋城市2021年夏季O3污染过程为例开展应用研究.结果表明,Correlation-ML-SHAP模型能够挖掘并利用强驱动因素模拟O3浓度和量化影响贡献,其中ML模块采用XGBoost模型模拟准确度最佳. 2021年夏季晋城市O3污染强驱动因素为:气温、日照强度、湿度和前体物排放水平,贡献权重为:32.1%、 21.3%、 16.5%和15.6%,其中气温、日照强度和前体物排放... 相似文献
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Adam Felton Ross A. Alford Annika M. Felton Lin Schwarzkopf 《Behavioral ecology and sociobiology》2006,59(6):786-795
We examined multiple mate choice criteria in Cophixalus ornatus, a terrestrial breeding, microhylid frog. Mate choice consisted of three stages: mate attraction (male calling), courtship
(male behavior between the call site and the nest), and nest site selection by the female. For male C. ornatus, the possession of a call with low dominant frequency relative to calling neighbors increased the probability that they would
attract females. Dominant frequency was negatively correlated with age independent of male mass and snout vent length. When
escorting the female from the call site to their nest, males traveled along more convoluted paths than when returning to the
nest alone. The convolution of the path was, therefore, considered an aspect of courtship. Females released eggs into nests
with structural characteristics typical of nests constructed by older males. Thus, females increased their chances of locating
an acceptable nest by preferentially approaching males with lower dominant frequencies. This study is the first to demonstrate
that age, independent of mass or snout-vent length, can influence call characteristics in anurans, and it is also the first
to demonstrate the importance of male age to female mate choice in an amphibian. 相似文献
544.
We used an immunofluorescence technique to investigate the effects of varying light regimes on ribulose 1,5-bisphosphate
carboxylase/oxygenase (Rubisco) in individual cells of the chlorophyte Dunaliella tertiolecta Butcher. These studies were carried out between September 1995 and February 1996. The population was heterogeneous with respect
to Rubisco localization in the pyrenoid, i.e. in some cells Rubisco staining was highly concentrated in the pyrenoid while
in others it was evenly distributed throughout the chloroplast stroma. When light intensity was varied sevenfold, the fraction
of the cell population that displayed distinct Rubisco staining in the pyrenoid (PR-index) was correlated with light intensity,
although the average Rubisco abundance per cell or per total cellular protein appeared fairly constant. In darkness, or when
treated with 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU), the PR-index decreased markedly during the first 4 and 3 h,
respectively, and then remained at low levels, while the cell division cycle progression remained unaffected. We conclude
that D. tertiolecta probably possesses an adaptive mechanism, i.e. the redistribution of Rubisco between the pyrenoid (probably the active site
of Rubisco activation and CO2 fixation) and the stroma (probably a reservoir of deactivated Rubisco that is readily available for transport to the pyrenoid
and activation), to respond to variations in irradiance or photosynthetic inhibition. Our results also suggest that this mechanism
is insensitive to slight variations in growth irradiance and to seasonal changes in photoperiod and temperature.
Received: 19 August 1996 / Accepted: 12 September 1996 相似文献
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农村水环境保护与经济可持续发展 总被引:1,自引:0,他引:1
我国的生态环境问题 ,如水土流失、草场退化、沙漠化、盐渍化等问题 ,归根到底还是农村水环境问题。本文分析了农村水环境保护、高效利用水资源的紧迫性 ,以及影响农村生态系统可持续性的因素和保护、改善农村水环境的主要措施 ;认为加强农村水环境保护及其持续发展能力的建设是我国整个社会特别是农村经济可持续发展的基本保障 相似文献
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We studied the influence of hydroxypropylcyclodextrins (HPCDs) on the toxicity of some mixtures. Using the Photobacterium phosphoreum toxicity test, the joint toxicological effect for Mixture I (containing p-nitrobenzaldehyde and 1-nitronaphthalene) and Mixture II (containing p-nitrobenzaldehyde and malononitrile) were determined in water and in aqueous solutions of HPCDs. The results indicate that, although the toxicological joint effect for Mixture I (simple addition) differs from that of Mixture II (synergism), alpha- and beta-HPCD can significantly reduce the toxicity of the test compounds, whereas gamma-HPCD has only a slight effect. Explanations for these observations are given that invoke the molecular structure of the individual chemicals as well as the structures of HPCDs. This provides information to assist the application of HPCDs in remediation of environmental pollution. 相似文献
550.
本文分析了贵州西部环境灾害的形成原因,它既受自然因素的影响,也受人类活动的影响。并提出了防治贵州西部环境灾害的基本措施。 相似文献