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91.
清远市部分农村出生性别比偏高的主要原因是重男轻女的传统观念在许多地方依然有深厚的根基。计划生育政策堵塞了人们通过多育得男的途径 ,一些村民利用胎儿性别选择等手段人为地提高了出生性别比。但具体的情况往往在经济发达地区与山区有所不同。全面推广落实“关爱女孩行动”对出生性别比升高有明显的抑制作用。  相似文献   
92.
A number of highly publicized, controversial lapses in social responsibility within global supply chains have forced managers and scholars to reexamine long‐held perspectives on supplier selection. Extending Carter and Jennings’ department‐level study of purchasing social responsibility, our research assesses the role of supply managers’ ethical intentions and three key antecedents that drive socially responsible supplier selection. Comparing evidence from firms operating in China, the United States, and the United Arab Emirates, we identify three key drivers of supply managers’ ethical intentions and examine both their direct and indirect impacts on socially responsible supplier selection. We find differential support for the predictor relationships on supply manager ethical intentions across national contexts and mediated versus nonmediated models. These observations bear important implications for firms conducting global supply management.  相似文献   
93.
Based on a literature review, this article frames different stages of the foster care process, identifying a set of standardized measures in the American and Portuguese contexts which, if implemented, could contribute towards higher levels of foster success. The article continues with the presentation of a comparative study, based on the application of the Casey Foster Applicant Inventory-Applicant Version (CFAI-A) questionnaire, in the aforementioned contexts. Taking a comparative analyses of CFAI-A's psychometric characteristics in four different samples as a starting point, one discovered that despite the fact that the questionnaire was adapted to Portuguese reality, it kept the quality values presented on the American samples. It specifically shows significant values regarding reliability and validity. This questionnaire, which aims to assess the potential of foster families, also supports the technical staff's decision making process regarding the monitoring and support of foster families, while it also promotes a better decision in the placement process towards the child's integration and development.  相似文献   
94.
闫懋博  田茂再 《统计研究》2021,38(1):147-160
Lasso等惩罚变量选择方法选入模型的变量数受到样本量限制。文献中已有研究变量系数显著性的方法舍弃了未选入模型的变量含有的信息。本文在变量数大于样本量即p>n的高维情况下,使用随机化bootstrap方法获得变量权重,在计算适应性Lasso时构建选择事件的条件分布并剔除系数不显著的变量,以得到最终估计结果。本文的创新点在于提出的方法突破了适应性Lasso可选变量数的限制,当观测数据含有大量干扰变量时能够有效地识别出真实变量与干扰变量。与现有的惩罚变量选择方法相比,多种情境下的模拟研究展示了所提方法在上述两个问题中的优越性。实证研究中对NCI-60癌症细胞系数据进行了分析,结果较以往文献有明显改善。  相似文献   
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96.
翻译对现代社会发展的贡献是巨大的。翻译研究近年来一直受到学术界的重视,有关翻译理论与实践的讨论也从未停止过。翻译本身受到诸多因素的影响,如文化因素、宗教因素、政治因素、译者自身的因素等等。从宏观的国际政治学角度审视翻译活动可以发现,翻译作为国际文化传播的一种形式,也不可避免地受到国家综合国力的影响和制约。  相似文献   
97.
 统计学博士是统计科研的中坚力量之一,其博士论文在一定程度上反映了当时我国统计学科研的热点和前沿,代表着我国统计教育的先进水平。本文通过对1987-2009年509篇统计学博士学位论文的选题及其研究内容进行统计,分析其变动规律和特点,总结选题的得失与启示,为今后科学选题以及进一步深入开展统计学术研究提供参考依据。  相似文献   
98.
99.
In industrial purchasing contexts firms often procure a set of products from the same suppliers to benefit from economies of scale and scope. These products are often at different stages of their respective product life cycles (PLCs). Firms consider multiple criteria in purchasing such products, and the relative importance of these criteria varies depending on the PLC stage of a given product. Therefore, a firm should select suppliers and choose sourcing arrangements such that product requirements across multiple criteria are satisfied over time. The extant models in sourcing literature for evaluating and selecting suppliers for a portfolio of products have not considered this important and practical issue faced by firms. This article proposes a mathematical model that effectively addresses this issue and contributes to the sourcing literature by demonstrating an approach for optimally selecting suppliers and supplier bids given the relative importance of multiple criteria across multiple products over their PLC. The application of the model on a hypothetical data set illustrates the strategic and tactical significance of such considerations.  相似文献   
100.
This article concerns inference on the correlation coefficients of a multivariate normal distribution. Inferential procedures based on the concepts of generalized variables (GVs) and generalized pp-values are proposed for elements of a correlation matrix. For the simple correlation coefficient, the merits of the generalized confidence limits and other approximate methods are evaluated using a numerical study. The study indicates that the proposed generalized confidence limits are uniformly most accurate even for samples as small as three. The results are extended for comparing two independent correlations, overlapping and non-overlapping dependent correlations. For each problem, the properties of the GV approach and other asymptotic methods are evaluated using Monte Carlo simulation. The GV approach produces satisfactory results for all the problems considered. The methods are illustrated using a few practical examples.  相似文献   
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