Uncertainty and Variation in Indirect Exposure Assessments: An Analysis of Exposure to Tetrachlorodibenzo-p-Dioxin from a Beef Consumption Pathway

Indirect exposures to 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) and other toxic materials released in incinerator emissions have been identified as a significant concern for human health. As a result, regulatory agencies and researchers have developed specific approaches for evaluating exposures from indirect pathways. This paper presents a quantitative assessment of the effect of uncertainty and variation in exposure parameters on the resulting estimates of TCDD dose rates received by individuals indirectly exposed to incinerator emissions through the consumption of home-grown beef. The assessment uses a nested Monte Carlo model that separately characterizes uncertainty and variation in dose rate estimates. Uncertainty resulting from limited data on the fate and transport of TCDD are evaluated, and variations in estimated dose rates in the exposed population that result from location-specific parameters and individuals'behaviors are characterized. The analysis indicates that lifetime average daily dose rates for individuals living within 10 km of a hypothetical incinerator range over three orders of magnitude. In contrast, the uncertainty in the dose rate distribution appears to vary by less than one order of magnitude, based on the sources of uncertainty included in this analysis. Current guidance for predicting exposures from indirect exposure pathways was found to overestimate the intakes for typical and high-end individuals.     

二人转的野性空间

东北人心中的二人转绝不仅仅是形式上的技艺杂耍,绝不仅仅是无意味的笑,它是东北民众自然而然的人生体验表达,它是苦寒东北人的“开心钥匙”。民间艺人与民间观众在二人转观演时空里无拘无束地大胆创造,尽情释放着自己的情感。它是博大的,自由的,野性的。在这个“市场时代”里,二人转发生了种种变异,面对二人转的当代存在状况,追述其厚实的文化艺术传统,我们发现二人转这种“间性”艺术品格源于二人转“二”的形态。     

论邓小平对我国社会主义民主政治建设的正确导向

邓小平对我国社会主义民主政治建设作了许多精辟论述,提出了许多重要思想,其中最具导向性的是:强调我国民主政治要中国化、制度化、法律化、渐进化、科学化.这些思想包括了我国民主政治建设的基本原则、根本任务、重要保证、基本途径和发展方向.它们相互联系,构成一个科学的体系,指导着我国新时期的民主政治建设健康持续协调地发展,对新世纪新阶段发展我国社会主义民主政治,建设社会主义法治国家,建设社会主义政治文明具有重要的指导意义.     

论张爱玲《传奇》叙事的心理时间模式

张爱玲的<传奇>创造的是现代都市生活中的"新传奇",所力图营造的是一种普通人平凡生活中的"奇异的感觉".在直接体现这一"心理传奇"理念的叙事策略中,张爱玲将个体意义上的生命体验加以逆向性地截取,在"变异"的心理时间上进行片段而又具有回顾意味的叙事,使所有的传奇故事都在"陈旧而模糊"的回忆中,沉浸于"无法挣脱的时代梦魇".其所形成的"奇异"的心理真实,在消解了"日常"生活的现实意义之后,充分传达出一种个体生存无法摆脱的苍凉感.     

近体诗句法变异的韵律与语用分析--以杜甫诗为例

成分异置是近体诗最重要的句法变异现象,其基本成因有二韵律规则对句法结构的客观制约;语用上对诗句词序的主观调动.韵律对句法的牵制体现在整体句法格局和具体结构选择两个层面上.其中节奏的力量不可忽视,尤其是"双字头"、"三字尾"起着潜在而强有力的作用.诗人为交际和诗性需求对诗句结构的变异处理,包括因话题化、焦点化、认知化、诗语化而形成的错位.总之,古典诗句句法结构变异是韵律规则和语用规则综合作用的结果.     

变分法教学与研究

本文应用变分原理导出天体运行轨道为圆锥曲线;且在一般极值曲线场申研究了变分问题,得到了一般变分公式的直接证明.     

Inter- and intra-population variations in diapause attribute of the two-spotted spider mite,Tetranychus urticae Koch, in Japan

Summary Populations of the two-spotted spider mite,Tetranychus urticae Koch collected from various localities and from various host plants in Japan showed wide variations in diapause attribute. Diapause percentages at 18°C/9L15D varied from nearly 100% in the north to 0% in the south-west. At intermediate latitudes the mites showed wide inter-population variations. Populations on herbaceous hosts in vinyl- or glass-houses gave significantly lower incidence of diapause than those on roses and deciduous fruit trees. Presence of winter hosts and better host quality under protected environments seemed to favour non-diapausing mites. The temperature threshold for diapause expression also varied widely among local populations. Northern populations consistently had higher and less variable thresholds than populations at intermediate latitudes with thresholds between 15 and 18°C. Inbred lines derived from a population in Kyoto exhibited a wide variation in diapause percentage at 18°C. These results show that diapause inT. urticae is a quantitative threshold trait and that populations in central Japan consist of a variety of genotypes with different diapause traits. This might provide a genetic source for adaptation to local and temporal variations in environmental conditions.     

Reproduction and egg diapause of the oriental chinch bug,Cavelerius saccharivorus okajima (Heteroptera: Lygaeidae), in the subtropical winter season in relation to its wing polymorphism

Summary Reproduction and egg diapause of the oriental chinch bug,Cavelerius saccharivorus, in the subtropical winter season were investigated in relation to its wing polymorphism. Macropterous females collected from the southern part of Okinawa Is. in the autumn season delayed their oviposition and were less fecund early in the adult life period, but survived much longer than brachypterous females collected from the same locality. The total fecundity was not significantly different between wing morphs. The diapause of eggs laid by brachypters tended to be terminated more easily at a high temperature than that of eggs laid by macropters. This indicated that the eggs laid by macropters were more intense in their diapause than those laid by brachypters. However, irrespective of the parental wing form, diapause showed considerable variation in its intensity within and between clutches.     

机器人装配作业的Hopfield神经网络的稳定性研究

本文运用Ｌｙａｐｕｎｏｖ第二方法及神经网络的稳定性判据，对用于机器人装配作业的Ｈｏｐｆｉｅｌｄ网络的稳定性进行了分析研究，并经实验验证，得到了较为满意的结果。     

一条磨光的拟合曲线

本文是通过对类似直角梯形的曲线进行磨光,而构造的一条光滑拟合曲线。