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1.
If a population contains many zero values and the sample size is not very large, the traditional normal approximation‐based confidence intervals for the population mean may have poor coverage probabilities. This problem is substantially reduced by constructing parametric likelihood ratio intervals when an appropriate mixture model can be found. In the context of survey sampling, however, there is a general preference for making minimal assumptions about the population under study. The authors have therefore investigated the coverage properties of nonparametric empirical likelihood confidence intervals for the population mean. They show that under a variety of hypothetical populations, these intervals often outperformed parametric likelihood intervals by having more balanced coverage rates and larger lower bounds. The authors illustrate their methodology using data from the Canadian Labour Force Survey for the year 2000.  相似文献   
2.
Annual concentrations of toxic air contaminants are of primary concern from the perspective of chronic human exposure assessment and risk analysis. Despite recent advances in air quality monitoring technology, resource and technical constraints often impose limitations on the availability of a sufficient number of ambient concentration measurements for performing environmental risk analysis. Therefore, sample size limitations, representativeness of data, and uncertainties in the estimated annual mean concentration must be examined before performing quantitative risk analysis. In this paper, we discuss several factors that need to be considered in designing field-sampling programs for toxic air contaminants and in verifying compliance with environmental regulations. Specifically, we examine the behavior of SO2, TSP, and CO data as surrogates for toxic air contaminants and as examples of point source, area source, and line source-dominated pollutants, respectively, from the standpoint of sampling design. We demonstrate the use of bootstrap resampling method and normal theory in estimating the annual mean concentration and its 95% confidence bounds from limited sampling data, and illustrate the application of operating characteristic (OC) curves to determine optimum sample size and other sampling strategies. We also outline a statistical procedure, based on a one-sided t-test, that utilizes the sampled concentration data for evaluating whether a sampling site is compliance with relevant ambient guideline concentrations for toxic air contaminants.  相似文献   
3.
"There are numerous reasons why mortality and life expectancy vary between countries. Epidemiological studies seem to indicate that dietary variations may be among them. A sample of 51 countries studied with data from the International Comparisons Project and other sources, shows that after controlling for nutrient intake, consumption of medical goods and services, income distribution, weather, and literacy, countries with more meat and poultry in their diet have lower life expectancies after age five. The results for infant mortality and child death between one and five indicate that a more animal-intensive diet may be actually beneficial, especially if fish consumption is increased and meat and poultry consumption reduced."  相似文献   
4.
详细分析了TE极化波以大角度入射到无金属基底的平面多层吸波结构上时的反射特性,导出连接层间电磁场的通用矩阵公式,计算了两层和三层吸波结构的反射系数,并证明了在何种条件下可以获得低的反射率,在此基础上提出了一个简易设计方法。对进气道和进气道内吸波导流板的两层和三层材料设计都获得了良好的特性。  相似文献   
5.
Effective supply chain management (SCM) has become a potentially valuable way of securing competitive advantage and improving organizational performance since competition is no longer between organizations, but among supply chains. This research conceptualizes and develops five dimensions of SCM practice (strategic supplier partnership, customer relationship, level of information sharing, quality of information sharing, and postponement) and tests the relationships between SCM practices, competitive advantage, and organizational performance. Data for the study were collected from 196 organizations and the relationships proposed in the framework were tested using structural equation modeling. The results indicate that higher levels of SCM practice can lead to enhanced competitive advantage and improved organizational performance. Also, competitive advantage can have a direct, positive impact on organizational performance.  相似文献   
6.
Qualitative Sociology - In democracies, political institutions based on deliberation offer citizens scope for talk-based participation in development and governance. A prominent example is the...  相似文献   
7.
Emotion has become an increasingly important aspect of work in the 21st century. In this article, we take stock of the extant literature delineating the role of emotions, especially passion as a cultural schema, in white‐collar workplaces. Scholars have covered extensive ground on emotions at work, but the role of passion remains an underexplored yet significant area. Drawing from recent developments in research on white‐collar work, we argue that the passion schema has become a critical marker in the labor market for sorting individuals into occupations, hiring and promotion within organizations, and assigning value to people's labor. Emergent research suggests that because the expression and perception of passion remain ambiguously defined in the workplace and varies by context, it is pivotal in reproducing social inequalities. In this review, we focus on how privileging passion in the workplace and interpreting it as a measure of aptitude impacts social inequalities by race, gender, and social class. We close by setting an agenda for further research on this topic.  相似文献   
8.
提出了一个应用遗传算法的电路模拟多层吸收体的新设计、遗传算法自动综合各层的电磁参数和厚度以及金属电路屏的各参数,并同时提供几个设计方案。当应用遗传算法对特宽带吸收体设计时,其迭代过程出现波动和在带内出现不好的结果。为了克服这些缺点,文中引入了两项技术,使其工作特性明显地改善。设计实例表明在无金属基底的吸收体情形,电路模拟吸收体比普通设计优越得多,在厚度更小和用更少材料下能在特宽带内获得低反射。  相似文献   
9.
饶伟新 《民族研究》2005,(6):92-100
针对目前客家学界认为今日"客家"的名称产生于明清时期,等同于明清文献中的"客佃"、"客籍"这一流行观点,本文以清代以来赣南文献中的"客佃"、"客籍"与"客家"为例,从区域社会史的角度对这些术语的具体历史语境和历史内涵进行考察和分析.指出清代的"客佃"、"客籍"作为清代移垦过程和户籍制度背景下特定的历史产物,其实是一个与"土著"、"土籍"相对的移民范畴,而今日所谓的"客家",则是在晚清民国以来社会文化变迁和学术发展背景下出现或建构的一个具有人类学意义的民系范畴,二者完全属于不同的历史范畴,故而不能相提并论.  相似文献   
10.
Although various studies have emphasized linkages between firm competencies, networks and sustainability at organizational level, the links between top management tangible competencies (TMTCs) (e.g. contemporary relevant quantitative‐focused education such as big data analytics and data‐driven applications linked with the internet of things, relevant experience and analytical business applications), relationship‐based business networks (RBNs) and environmental sustainability have not been well established at micro‐level, and there is a literature gap in terms of investigating these relationships. This study examines these links based on the unique data collected from 175 top management representatives (chief executive officers and managing directors) working in food import and export firms headquartered in the UK and New Zealand. Our results from structural equation modelling indicate that TMTCs are the key determinants for building RBNs, mediating the correlation between TMTCs and environmental sustainability. Directly, the competencies also play a vital role towards environmental practices. The findings further depict that relationship‐oriented firms perform better compared to those which focus less on such networks. Consequently, our findings provide a deeper understanding of the micro‐foundations of environmental sustainability based on TMTCs rooted in the resource‐based view and RBNs entrenched in social network theory. We discuss the theoretical and practical implications of our findings, and we provide suggestions for future research.  相似文献   
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