Predicting body fat using weight–height indices

While body fat is the most accurate measure of obesity, its measurement requires special equipment that can be costly and time consuming to operate. Attention has thus typically focused on the easier to calculate body mass index (BMI). However, the ability of BMI to accurately identify obesity has been increasingly questioned. This paper focuses attention on whether more general body mass indices are appropriate measures of body fat. Using a data set of body fat, height, and weight measurements, general models are estimated which nest a wide variety of weight–height indices as special cases. In the absence of a race and gender categorisation, the conventional BMI was found to be the appropriate index with which to predict body fat. When such a categorisation was made, however, the BMI was never selected as the appropriate index. In general, predicted female body fat was some 10 kg higher than that of a male of identical build and predicted % body fat was over 11 percentage points higher, but age effects were smaller for females. Considerable racial differences in predicted body fat were found for males, but such differences were less marked for females. The implications of this finding for interpreting recent research on the effect of obesity on health, society, and economic factors are considered.     

Early-life conditions and adult mortality decline in Dutch cohorts born 1812–1921

Mounting evidence suggests that early-life conditions have an enduring effect on an individual’s mortality risks as an adult. The contribution of improvements in early-life conditions to the overall decline in adult mortality, however, remains a debated issue. We provide an estimate of the contribution of improvements in early-life conditions to mortality decline after age 30 in Dutch cohorts born between 1812 and 1921. We used two proxies for early-life conditions: median height and early-childhood mortality. We estimate that improvements in early-life conditions contributed more than five years or about a third to the rise in women’s life expectancy at age 30. Improvements in early-life conditions contributed almost three years or more than a quarter to the rise in men’s life expectancy at age 30. Height appears to be the more important of the two proxies for early-life conditions.     

浅析中国古代食具碗造型的发展规律

"碗"是中国古代最主要的饮食器具,其器型称谓经历了多次变化.从材质上讲,它经历了陶器、瓷器、漆器和银器等几个演化阶段;从功能和形式上讲,碗的口径和高度大小均满足东方人对碗的使用要求.这说明中国古代的碗,在前期其功能变化不大,形制也较为单一.随着人们对自己和器物关系的规律性认识的不断深化,器物的型制也从单一走向多样,并逐渐形成了后期比较明确的功能性造型取向,这对现代设计有着启示借鉴作用.     

Nonparametric control charts based on runs and Wilcoxon-type rank-sum statistics

In this article, we introduce three new distribution-free Shewhart-type control charts that exploit run and Wilcoxon-type rank-sum statistics to detect possible shifts of a monitored process. Exact formulae for the alarm rate, the run length distribution, and the average run length (ARL) are all derived. A key advantage of these charts is that, due to their nonparametric nature, the false alarm rate (FAR) and in-control run length distribution is the same for all continuous process distributions. Tables are provided for the implementation of the charts for some typical FAR values. Furthermore, a numerical study carried out reveals that the new charts are quite flexible and efficient in detecting shifts to Lehmann-type out-of-control situations.     

Demography and Social Science

Research has demonstrated that son preference has a serious impact on the survival and well-being of female infants and children in some parts of South and East Asia, but little is known about the consequences of son preference in later childhood and adolescence. We compare children's growth trajectories in height over childhood and adolescence in China, where the level of son preference is relatively high, and the Philippines, where it is relatively low. Children's height reflects long-term nutritional status and exposure to infectious diseases, both influenced by household decision-making and, presumably, by a preference for sons. Using data from two high-quality longitudinal studies and multilevel growth models, we find that male children in China show an additional height advantage relative to their female counterparts, when compared to the sex difference in growth trajectories in the Philippines. Further analysis reveals that the additional advantage of males in China is stronger in rural areas.     

A Trivariate Distribution for the Height,Weight, and Fat of Adult Men*

Using exploratory data analysis, probability plots, scatterplots, and computer animations to rotate and visualize the data, we fit a trivariate Normal distribution to data for the height, the natural logarithm of body weight, and the body fat for 646 men between the ages of 50 and 80 years as reported by the medical staff of the U.S. Veterans Administration's “Normative Aging Study” in Boston, MA. Although these data do not include any children, women, or young men, the measurements represent the best data that we could find through a 4-year search. We believe that these data are well measured and reliable for men in the specified age range and that these data reveal an interesting statistical pattern for use in probabilistic PBPK models.     

胶辊数字中高机的设计

针对印刷机中普通胶辊由于胶辊扰度造成印制品厚薄不均的问题,以中高度法原理为依据,提出了将中高度曲 线方程解析成以时间为变量的函数,用单片机计算和控制中高机运动,设计了以单片机、交流伺服控制器、变频器和磨头 等构建的一个数字控制系统为核心的胶辊数字中高机。应用结果表明数字中高机可安装在普通车床上实现中高胶辊的 加工,且中高曲线和中高度可任意设置,设计简便实用,便于推广。     

角谷变换下的正奇数分类及其马氏链模型

考虑在角谷变换F下，将全体正奇数N1进行分类，得到正奇数N1的等价二叉树模型；另一方面，发现三类正奇数在角谷变换F下的马氏链模型，是模为2^n的同余吸收链的极限形式．     

我们要构筑三大经济发展高地

谋划城镇的发展，首先应搞清楚我们的经济高地在哪里，有的放矢，才能减少决策失误，降低开发成本，加快发展速度，提高经济质量，实现科学发展。在全球化时代，我们要积极构筑“三大经济发展高地”，才能占领制高点，掌握经济发展的话语权和主动权。     

黄化型大麦的系列研究 Ⅲ南黄大麦生长发育的调查

本文系统地报道了南黄大麦与原品种早熟3号在生育期、植株高度、叶片长宽、分蘖数以及穗部性状等方面的比较.指出南黄大麦除出土时间,倒二叶的长宽与早熟3号基本一致,剑叶长宽略大于早熟3号外,其余性状差异显著.植株矮小,生长发育缓慢,这与黄化型大麦叶色浅,叶绿体的片层结构不发达,光合机能弱,光合产物少有关.