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21.
首先分析了对数最小二乘排序法的特点,说明它是一种值得重视的好方法;并进一步阐述了这一方法的基本原理,着重地对群体判断下求加权的综合排序向量的方法进行了严密的数学推导;提出了在加权的综合排序中权重系数确定的新見解,并举例子以解释。  相似文献   
22.
对于马克思主义“两个必然”和“两个决不会”的关系存在着“补充论”、“修正论”、“取代论”的不同观点。“两个必然”和“两个决不会”的科学论断都是社会基本矛盾运动规律的体现,二者是内在的高度统一的理论。就资本主义社会发展趋势而言,“两个决不会”具有相对性,是“两个必然”的内在要求,“两个必然”理论中包含着“两个决不会”思想,是“两个决不会”运动的最终结果。  相似文献   
23.
利用漫反射法获得环丙沙星短波近红外光谱(700-1100nm),采用化学计量学中的偏最小二乘法(PLS),选取不同的波长范围及不同的光谱预处理方法(一阶导数和和二阶导数)对光谱进行信息提取和分析,对盐酸环丙沙星粉末药品进行了无损非破坏定量分析,以样品中盐酸环丙沙星为活性成分建立了最佳的数学校正模型。讨论了主成分数对PLS模型定量预测能力的影响,并做了比较。  相似文献   
24.
Longitudinal data often contain missing observations, and it is in general difficult to justify particular missing data mechanisms, whether random or not, that may be hard to distinguish. The authors describe a likelihood‐based approach to estimating both the mean response and association parameters for longitudinal binary data with drop‐outs. They specify marginal and dependence structures as regression models which link the responses to the covariates. They illustrate their approach using a data set from the Waterloo Smoking Prevention Project They also report the results of simulation studies carried out to assess the performance of their technique under various circumstances.  相似文献   
25.
明代中国戏曲的兴盛、繁荣主要集中在江南地区 ,而北方戏曲衰落似成定论。通过对较为丰富、详实的明代山西地区戏曲文物史料的把握 ,即从戏曲舞台兴建、服饰化妆、乐队的组成、唱腔和剧目这几方面去考证明代山西戏曲的兴盛史 ,可以为缺少明代北方戏曲史料记载的中国戏曲史作一补充。  相似文献   
26.
Beryllium is the strongest of the lightweight metals. Used primarily in military applications prior to the end of the Cold War, beryllium is finding new applications in many commercial products, including computers, telecommunication equipment, and consumer and automotive electronics. The use of beryllium in nondefense consumer applications is of concern because beryllium is toxic. Inhalation of beryllium dust or vapor causes a chronic lung disease in some individuals at concentrations as low as 0.01 microg/m3 in air. As beryllium enters wider commerce, it is prudent to ask what risks this might present to the general public and to workers downstream of the beryllium materials industry. We address this question by evaluating the potential for beryllium exposure from the manufacturing, use, recycle, and disposal of beryllium-containing products. Combining a market study with a qualitative exposure analysis, we determine which beryllium applications and life cycle phases have the largest exposure potential. Our analysis suggests that use and maintenance of the most common types of beryllium-containing products do not result in any obvious exposures of concern, and that maintenance activities result in greater exposures than product use. Product disposal has potential to present significant individual risks, but uncertainties concerning current and future routes of product disposal make it difficult to be definitive. Overall, additional exposure and dose-response data are needed to evaluate both the health significance of many exposure scenarios, and the adequacy of existing regulations to protect workers and the public. Although public exposures to beryllium and public awareness and concern regarding beryllium risks are currently low, beryllium risks have psychometric qualities that may lead to rapidly heightened public concern.  相似文献   
27.
山西寺庙戏场建筑研究--戏台位置剖析   总被引:1,自引:0,他引:1  
山西的戏曲文化历史悠久 ,与之相应 ,山西的戏场建筑数量多、价值高。在大量实地调研的基础上 ,从戏场建筑的功能特点出发 ,阐释了山西传统寺庙戏场的布局特点 ,论述了戏台和山门之间几种常见的位置关系。  相似文献   
28.
How do new parents differ from their childless counterparts in social and psychological resources, daily strains, and psychological well‐being? Using a nationally representative panel of 1,933 adults who were childless at the first interview, we compare 6 indicators of adults' lives for those who became parents and those remaining childless several years later, controlling for earlier states. Becoming a parent is both detrimental and rewarding. With the exception of social integration, which is greater for all groups of new parents compared with their childless counterparts, the effects of parental status on adults' lives vary markedly by gender and marital status. Unmarried parents report lower self‐efficacy and higher depression than their childless counterparts. Married mothers' lives are marked by more housework and more marital conflict but less depression than their childless counterparts. Parental status has little influence on the lives of married men.  相似文献   
29.
This article explores two problems analysts face in determining how to estimate values for children's health and safety risk reductions. The first addresses the question: Do willingness‐to‐pay estimates for health risk changes differ across children and adults and, if so, how? To answer this question, the article first examines the potential effects of age and risk preferences on willingness to pay. A summary of the literature reporting empirical evidence of differences between willingness to pay for adult health and safety risk reductions and willingness to pay for health and safety risk reductions in children is also provided. The second dimension of the problem is a more fundamental issue: Whose perspective is relevant when valuing children's health effects—society's, children's, adults‐as‐children, or parents'? Each perspective is considered, followed ultimately by the conclusion that adopting a parental perspective through an intrahousehold allocation model seems closest to meeting the needs of the estimation problem at hand. A policy example in which the choice of perspective affects the outcome of a regulatory benefit‐cost analysis rounds out the article and emphasizes the importance of perspective.  相似文献   
30.
汉民族是我国乃至世界上最大的民族 ,而关于汉民族的研究 ,长期以来却被国内学术界所忽视 ,汉民族史常被淹没在通史和断代史研究之中。十一届三中全会后 ,汉民族研究如雨后春笋 ,一直在不断地兴旺勃发。特别是近二十年来 ,汉民族研究取得了蔚为壮观的成绩 ,为世人瞩目。  相似文献   
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