排序方式: 共有77条查询结果,搜索用时 15 毫秒
71.
Every year across America, tens of thousands of soil samples are collected and analyzed for the presence of toxic contaminants. From among these sampling results, “hot spots”; of soil contamination are identified. One or more hot spots on a property precipitates follow‐up activities, typically at great expense. Given that costly action is undertaken as a result of this identification, it is surprising that there is no objective approach to identifying what is or is not a hot spot of soil contamination. A new approach considers how soil contamination can lead to potentially health‐threatening exposures. Based on this approach, an objective set of characteristics for a hot spot of soil contamination has been developed. 相似文献
72.
标准化是解决环境损害"鉴定难"问题的关键措施,更是环境损害鉴定评估走向独立化的重要标志。农业环境损害鉴定评估作为起步最早、需求量最大、成长较快的分支,已经具备标准体系的雏形。通过国内外标准比较与需求分析,提出了标准化建设的原则和定位,构建了标准体系框架。研究认为,我国农业环境损害鉴定评估标准体系应:(1)以损害受体和技术流程为纵向横向坐标;(2)围绕损害确认、因果关系判定以及损失评估,以规范农产品、农业环境要素以及生态系统的损害识别、症状诊断、损害溯源、监测检测方法、损失量化等技术要求为主要内容;(3)是一个由基础标准、技术导则、技术规范、技术指南组成的有机整体。 相似文献
73.
目的 探讨聚类分析法在确定护理单元分类中的应用,客观、公正的评价护理单元,在医护分开核算模式下,为护理绩效奖金分配及人力资源配置提供参考依据。方法 利用自设调查表及某公司提供的量表,抽样统计护理人员对护理单元分类的主观评价,应用聚类分析法,结合客观业务数据,确定不同护理单元的分类。结果 将全院78个护理单元分为1类至5类共5个类别,1类护理单元9个,2类护理单元21个,3类护理单元22个,4类护理单元12个,5类护理单元14个。结论 调整后的护理单元聚类值作为护理单元分类系数,能够全面、客观、相对公平的反映不同护理单元的护理工作负荷、难度及风险,可以作为医院护理绩效考评奖金分配及科室管理的依据。 相似文献
74.
75.
Female-solicited extrapair matings in Humboldt penguins fail to produce extrapair fertilizations 总被引:4,自引:2,他引:2
Schwartz Michael K.; Boness Daryl J.; Schaeff Catherine M.; Majluf Patricia; Perry Elizabeth A.; Fleischer Robert C. 《Behavioral ecology》1999,10(3):242-250
The study reported in this paper demonstrated that Humboldtpenguins at
Punta San Juan, Peru, despite forming pair-bonds,are not strictly monogamous
in their mating behavior: 19.2%of the study males and 30.7% of the study
females (21 nests)engaged in extrapair copulations. The total number of
completedmatings observed during the course of this study was 106, ofwhich
17.9% were extrapair copulations. Using DNA fingerprintingwe demonstrated
that none of these extrapair copulations resultedin extrapair fertilizations;
all 49 offspring were attributedto the putative father. Location of
copulations suggested thatfemales solicited these extrapair copulations
because 89.2%of Humboldt penguin within-pair copulations occurred at thehome
burrow, yet extrapair copulations took place at a differentlocation based on
the sex of the penguin. Extrapair copulationsby males occurred at their nest,
whereas females conducted 92%of their extrapair copulations away from the
nest. These resultsare most consistent with mate-appraisal and epiphenomenal
hypotheses. 相似文献
76.
77.
为了利用微藻处理废水生产生物质燃料,实现治理环境污染和缓解化石能源短缺的耦合,需要筛选能够适应石家庄本地气候,生产状况良好且油脂产率较高的微藻藻株。从石家庄市自然河流中采样,经过BG11培养基分离纯化后筛选出10株微藻,利用SPASS 19.0软件对培养中的相关数据进行方差分析及LSD多重比较发现,自养条件下藻种DK-3生物量、总脂含量较其他藻株高,分别为:1.86 g·L-1、(10.23 ± 2.63) mg·L-1·d-1,经18S rDNA 鉴定为栅藻(Scenedesmus meyen),构建其系统发育树。利用Box-Behnken Design (BBD)设计耦合响应曲面法(RSM)探索藻种DK-3最佳异养培养条件,最终藻种DK-3最佳培养条件为葡萄糖20 g·L-1、K2HPO4·3H2O 90 mg·L-1、MgSO4·7H2O 200 mg·L-1(其他成分参考BG11培养基),经验证在此培养条件下,经240 h培养后生物量为5.47 g·L-1,油脂产量为1.28 g·L-1,比对照组生物量3.37 g·L-1提高了62.31%,因此,藻种DK-3具有较高的研究潜能。 相似文献