针对目前学术虚拟社区知识交流效率研究均未剔除环境因素影响的问题,本文在分析环境因素对学术虚拟社区知识交流效率影响的基础上,剔除外生因素对学术虚拟社区知识交流效率的影响,为进一步客观评价学术虚拟社区的知识交流效率提供参考...针对目前学术虚拟社区知识交流效率研究均未剔除环境因素影响的问题,本文在分析环境因素对学术虚拟社区知识交流效率影响的基础上,剔除外生因素对学术虚拟社区知识交流效率的影响,为进一步客观评价学术虚拟社区的知识交流效率提供参考。本研究采用三阶段DEA(data envelopment analysis,DEA)模型,以“小木虫”论坛的有机交流、第一性原理、微米和纳米、金融投资4个版块为例,对比分析剔除外生因素前后学术虚拟社区知识交流效率的变化。研究结果发现,剔除外生因素的影响后,学术虚拟社区的知识交流效率有所提升,但仍未实现决策单元(decision making unit,DMU)有效;第一阶段和第三阶段的测算结果均显示第一性原理版块的知识交流效率最高;在环境变量对学术虚拟社区知识交流效率的影响中,散金数、用户总发帖、社区管理者参与度以及社区成员质量对学术虚拟社区知识交流效率有正向影响作用,而用户加入社区时长与用户在线时长等因素对社区知识交流效率有负向影响。展开更多
The paper reports 8 species of 7 genera of Encyrtidae, i. e. Anagyrus pseudococci, Cheiloneurus ceroplastis, Dusmetia fascipennis, Homalotylus ephippium associated with scale insects on trees, Isodromus atriventris...The paper reports 8 species of 7 genera of Encyrtidae, i. e. Anagyrus pseudococci, Cheiloneurus ceroplastis, Dusmetia fascipennis, Homalotylus ephippium associated with scale insects on trees, Isodromus atriventris, Isodromus collimaculatus sp. nov., Ooencyrtus kuvanae associated with lacewing insects, and Syrphophagus aeruginosus , a parasitoid of Syrphids. All specimens are deposited in the Department of Plant Protection, Zhejiang University, Hangzhou, China.展开更多
OBJECTIVE: To evaluate the in vivo antiplasmodial activity and the oral acute toxicity of the Bombax buonopozense root bark aqueous extract.METHODS: The in vivo antiplasmodial activity of the root bark aqueous extract...OBJECTIVE: To evaluate the in vivo antiplasmodial activity and the oral acute toxicity of the Bombax buonopozense root bark aqueous extract.METHODS: The in vivo antiplasmodial activity of the root bark aqueous extract of Bombax buonopozense against early and established rodent malaria infections in chloroquine sensitive Plasmodium berghei strain in mice was investigated, and oral acute toxicity of the aqueous root bark extract of Bombax buonopozense was also evaluated in mice.RESULTS: The findings of this study revealed significant(P < 0.05) and dose dependent decrease in parasitaemia in the parasitized groups treated with varying doses of the extract(50-200 mg/kg p.o.) in both suppressive and curative tests. There was also significant decrease in parasitaemia density in the chloroquine treated group. The aqueous extract was found no toxicity in mice and the oral LD50 was determined to be greater than 5000 mg/kg.CONCLUSION: Bombax buonopozense root bark aqueous extract possesses potent antiplasmodial activity and may therefore, serve as potential sources of new antimalarial agents.展开更多
文摘针对目前学术虚拟社区知识交流效率研究均未剔除环境因素影响的问题,本文在分析环境因素对学术虚拟社区知识交流效率影响的基础上,剔除外生因素对学术虚拟社区知识交流效率的影响,为进一步客观评价学术虚拟社区的知识交流效率提供参考。本研究采用三阶段DEA(data envelopment analysis,DEA)模型,以“小木虫”论坛的有机交流、第一性原理、微米和纳米、金融投资4个版块为例,对比分析剔除外生因素前后学术虚拟社区知识交流效率的变化。研究结果发现,剔除外生因素的影响后,学术虚拟社区的知识交流效率有所提升,但仍未实现决策单元(decision making unit,DMU)有效;第一阶段和第三阶段的测算结果均显示第一性原理版块的知识交流效率最高;在环境变量对学术虚拟社区知识交流效率的影响中,散金数、用户总发帖、社区管理者参与度以及社区成员质量对学术虚拟社区知识交流效率有正向影响作用,而用户加入社区时长与用户在线时长等因素对社区知识交流效率有负向影响。
基金Project funded by National Fund of Natural Science P.R.China!No.39970 620
文摘The paper reports 8 species of 7 genera of Encyrtidae, i. e. Anagyrus pseudococci, Cheiloneurus ceroplastis, Dusmetia fascipennis, Homalotylus ephippium associated with scale insects on trees, Isodromus atriventris, Isodromus collimaculatus sp. nov., Ooencyrtus kuvanae associated with lacewing insects, and Syrphophagus aeruginosus , a parasitoid of Syrphids. All specimens are deposited in the Department of Plant Protection, Zhejiang University, Hangzhou, China.
文摘OBJECTIVE: To evaluate the in vivo antiplasmodial activity and the oral acute toxicity of the Bombax buonopozense root bark aqueous extract.METHODS: The in vivo antiplasmodial activity of the root bark aqueous extract of Bombax buonopozense against early and established rodent malaria infections in chloroquine sensitive Plasmodium berghei strain in mice was investigated, and oral acute toxicity of the aqueous root bark extract of Bombax buonopozense was also evaluated in mice.RESULTS: The findings of this study revealed significant(P < 0.05) and dose dependent decrease in parasitaemia in the parasitized groups treated with varying doses of the extract(50-200 mg/kg p.o.) in both suppressive and curative tests. There was also significant decrease in parasitaemia density in the chloroquine treated group. The aqueous extract was found no toxicity in mice and the oral LD50 was determined to be greater than 5000 mg/kg.CONCLUSION: Bombax buonopozense root bark aqueous extract possesses potent antiplasmodial activity and may therefore, serve as potential sources of new antimalarial agents.