共查询到10条相似文献,搜索用时 78 毫秒
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Influence measures based on the pairwise deletion approach and the differentiation approach are developed for unmasking observations masked by other observations in the proportional hazards model. These influential observations might have substantial impact on statistical inference and might provide important information for model adequacy. One numerical example based on real data is presented and discussed. 相似文献
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European eels, Anguilla anguilla, L., are captured in coghill nets at three commercial weirs on the Irish River Shannon during their autumn/winter seaward migration. The variations in daily silver eel catches were analysed in relation to environmental conditions, especially hydrometric and meteorological factors. Three multivariate environmental axes were distinguished with which daily eel catches could be correlated. The relative importance of various hydrometric, meteorological and temporal (seasonality, lunar phase) factors was identified, showing how hydrological and meteorological factors generally obscure the underlying lunar periodicity of the silver eel migrations at Killaloe. 相似文献
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棉田烟粉虱种群动态及杀虫剂的影响 总被引:19,自引:1,他引:18
本文记述了烟粉虱(Bemisia tabaci(Gennadius))各龄若虫形态特征、生物学特性,以及1977—1984年八年的田间种群动态及杀虫剂对其影响.烟粉虱是上海郊区常发性棉田害虫,但密度较低,为害不重,除棉花外还为害大豆等作物.烟粉虱从7月上旬在棉田出现,8—9月为发生盛期.一般年份有三个高峰日,每年高峰日出现有一定规律.烟粉虱田间种群积累增长数和10℃以上积温呈S形曲线相关,文中给出不同数量类型年份的相关曲线,可以用于预测种群增长趋势.10月下旬以后种群数量明显下降.调查中发现二种寄生蜂寄生若虫,对粉虱种群有一定影 响.在每年用药7—9次的常规用药田块粉虱种群可以被压制到较低水平,但寄生蜂也全部损失,在每年用药3—4次的控药田块,虽粉虱数量较多,但寄生蜂数量也有上升趋势,而影响粉虱种群数量. 相似文献
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宠物伴随人类文明已有数千年的历史。目前,外来宠物日益受到玩家青睐,但它们也对当地生态环境存在一定不利影响。本文概括了我国外来宠物的现状,分析了外来宠物的潜在危害,探讨了在外来宠物及外来入侵生物管理方面存在的问题并提出了相应的管理对策。 相似文献
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调查住院癌症病人护理者医院生物生存状态,并对其影响因素进行研究.采用癌症病人护理者医院生物生存状态调查表和病人日常生活能力量表进行问卷调查.结果可见,护理工作使癌症病人护理者医院生物生存状态各维度得分及总分受到了不同程度的影响;作为配偶及父母的护理者生物生存状态较差,病人日常活动能力越差者,护理者的生物生存状态越差,有工作的护理者生物生存状态较高.改善护理者生物生存状态的措施应当针对减轻护理的客观工作量以及向护理者提供更多的信息和应对策略. 相似文献
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Maria Pérez-Marcos Maria Isabel Arnaldos Elena López-Gallego Aurelio Luna Azza Khedre Maria Dolores García 《法国昆虫学会纪事》2018,54(4):367-380
Summary. Since the entomosarcosaprophagous community is affected by environmental variables, it needs to be studied under different environmental conditions. In addition, because most studies are usually conducted with biomodels rather than human corpses, it is necessary to verify whether or not the type of decomposing animal matter affects the decomposition process itself, as well as the related fauna. For this reason, a study was conducted on the sarcosaprophagous Diptera community in two different environments of the Region of Murcia (SE Spain), using piglet and chicken carcasses, and Schoenly traps as collecting devices. To analyse possible differences regarding faunal composition among samples, a one-way Permutational Multivariate Analysis of Variance (PERMANOVA) was applied. The results indicate significant differences concerning the bait. In this sense, Calliphoridae, Muscidae, Fanniidae and Sarcophagidae families are the main groups responsible for such differences. In terms of environment-related differences, the only species that contribute are those of the dominant families, Calliphoridae and Muscidae. 相似文献