儿童拼图性识字的记忆研究

以艾宾浩斯的遗忘曲线为基本框架,通过拼图性学习和常规性学习两种不同学习生字方法的实验比较,对儿童识字的一般性规律进行研究。得到结论:拼图性识字在记忆的保持上优于常规性识字;拼图性识字在学习有笔画难度的字上优于常规性识字;拼图性识字同样符合艾宾浩斯的遗忘曲线规律。拼图性识字教学符合儿童以动作思维为主的认识特点,符合儿童心理的年龄特征,能提高对字形记忆的效果,让儿童可以有效、有趣、自主进行早期识字学习。     

Parenting as a Dynamic Process: A Test of the Resource Dilution Hypothesis

In this paper, we tested the resource dilution hypothesis, which posits that, because parenting resources are finite, the addition of a new sibling depletes parenting resources for other children in the household. We estimated growth curve models on the self‐reported parenting practices of mothers using four waves of data collected biennially between 1994 and 2000 on a nationally representative sample of 2,082 Canadian children aged 2 to 5 at initial interview and in continuously intact, two‐biological‐parent households. Results showed that when new children were added to the household, mothers exhibited declines in positive interaction, but increased their levels of consistent parenting. Taken together, these findings suggested that parenting resources were reallocated, rather than diluted, when family size increased.     

中美国债收益率比较分析——来自2002—2014 年国债市场的经验证据

国债收益率波动对于一国金融市场配置资源的效率,乃至金融市场的稳定具有重要影响。本文以2002-2014年中美国债市场数据为样本,从国债收益率曲线、收益率波动以及影响因素等方面对中美国债收益率进行了比较研究。结果发现,中国交易所市场和银行间市场国债收益率形态并不一致,中美国债收益率波动也具有各自特征;中美国债收益率对于美元指数变化的反应并不相同,当美元升值时,中美国债收益率表现出一定程度的趋同性,而当美元贬值时,中美国债收益率则表现出一定程度的背离;中美国债收益率对于物价指数变动的反应相同,均与各自国内物价指数间呈现正向关系。基于此,论文从丰富国债交易品种、完善交易机制、发挥国债市场资金价格功能等方面提出了完善我国国债市场发展的政策建议。     

Deconvolution methods for non-parametric inference in two-level mixed models

Summary.  We develop a general non-parametric approach to the analysis of clustered data via random effects. Assuming only that the link function is known, the regression functions and the distributions of both cluster means and observation errors are treated non-parametrically. Our argument proceeds by viewing the observation error at the cluster mean level as though it were a measurement error in an errors-in-variables problem, and using a deconvolution argument to access the distribution of the cluster mean. A Fourier deconvolution approach could be used if the distribution of the error-in-variables were known. In practice it is unknown, of course, but it can be estimated from repeated measurements, and in this way deconvolution can be achieved in an approximate sense. This argument might be interpreted as implying that large numbers of replicates are necessary for each cluster mean distribution, but that is not so; we avoid this requirement by incorporating statistical smoothing over values of nearby explanatory variables. Empirical rules are developed for the choice of smoothing parameter. Numerical simulations, and an application to real data, demonstrate small sample performance for this package of methodology. We also develop theory establishing statistical consistency.     

Confidence interval estimation of the difference between paired AUCs based on combined biomarkers

In many diagnostic studies, multiple diagnostic tests are performed on each subject or multiple disease markers are available. Commonly, the information should be combined to improve the diagnostic accuracy. We consider the problem of comparing the discriminatory abilities between two groups of biomarkers. Specifically, this article focuses on confidence interval estimation of the difference between paired AUCs based on optimally combined markers under the assumption of multivariate normality. Simulation studies demonstrate that the proposed generalized variable approach provides confidence intervals with satisfying coverage probabilities at finite sample sizes. The proposed method can also easily provide P-values for hypothesis testing. Application to analysis of a subset of data from a study on coronary heart disease illustrates the utility of the method in practice.     

分位数回归及应用简介

文章介绍了分位数回归法的概念、算法及主流统计软件R和SAS计算时的语法,并通过实例与以普通最小二乘法为基础的线性回归进行了对比,展现了分位数回归的巨大魅力。     

Examining the Impact of Demographic Factors on Air Pollution

This study adds to the emerging literature examining empirically the link between population size, other demographic factors and pollution. We contribute by using more reliable estimation techniques and examine two air pollutants. By considering sulfur dioxide, we become the first study to explicitly examine the impact of demographic factors on a pollutant other than carbon dioxide at the cross-national level. We also take into account the urbanization rate and the average household size neglected by many prior cross-national econometric studies. For carbon dioxide emissions we find evidence that population increases are matched by proportional increases in emissions while a higher urbanization rate and lower average household size increase emissions. For sulfur dioxide emissions, we find a U-shaped relationship, with the population-emissions elasticity rising at higher population levels. Urbanization and average household size are not found to be significant determinants of sulfur dioxide emissions. For both pollutants, our results suggest that an increasing share of global emissions will be accounted for by developing countries. Implications for the environmental Kuznets curve literature are described and directions for further work identified.     

Gini’s nuclear family

The purpose of this paper is to justify the use of the Gini coefficient and two close relatives for summarizing the basic information of inequality in distributions of income. To this end we employ a specific transformation of the Lorenz curve, the scaled conditional mean curve, rather than the Lorenz curve as the basic formal representation of inequality in distributions of income. The scaled conditional mean curve is shown to possess several attractive properties as an alternative interpretation of the information content of the Lorenz curve and furthermore proves to yield essential information on polarization in the population. The paper also provides asymptotic distribution results for the empirical scaled conditional mean curve and the related family of empirical measures of inequality.      

基于圆弧样条的复杂零件型面数控测量数据拟合

讨论了数控测量数据的一般处理方法及复杂零件型面多测量点数据对数控加工的影响．研究了利用圆弧样条拟合测量数据和生成加工刀位轨迹的方法．     

Sample Size and Power Calculation in Comparing Diagnostic Accuracy of Biomarkers with Pooled Assessments

When testing of a biomarker is costly, pooling of samples becomes a useful and efficient alternative (Faraggi et al., 2003). In this paper, we develop procedures for sample size and power calculations for planning a study comparing the accuracy of biomarkers in diagnosis of diseases with pooled samples. Explicit formulas are derived for several important pooling strategies. The effects of pooling samples on sample size and power of the test are also discussed.