Modelling period fertility: Schooling and intervals following a birth in Eastern Africa

We describe a regression-based approach to the modelling of age-, order-, and duration-specific period fertility, using retrospective survey data. The approach produces results that are free of selection biases and can be used to study differential fertility. It is applied to Demographic and Health Survey data for Ethiopia, Kenya, Tanzania, and Zimbabwe to investigate differential trends in fertility by education. Parity progression fell and the intervals following each birth lengthened between the 1970s and 2000s in all four countries. Fertility fell most among women with secondary education. In contrast to other world regions, postponement of successive births for extended periods accounted for much of the initial drop in fertility in these African countries. However, family size limitation by women with secondary education in Ethiopia and Kenya and longer birth spacing in Zimbabwe also played significant roles. Thus, birth control is being adopted in Eastern Africa in response to diverse changes in fertility preferences.     

Parameter estimation of three-parameter Weibull distribution based on progressively Type-II censored samples

In this paper, the estimation of parameters for a three-parameter Weibull distribution based on progressively Type-II right censored sample is studied. Different estimation procedures for complete sample are generalized to the case with progressively censored data. These methods include the maximum likelihood estimators (MLEs), corrected MLEs, weighted MLEs, maximum product spacing estimators and least squares estimators. We also proposed the use of a censored estimation method with one-step bias-correction to obtain reliable initial estimates for iterative procedures. These methods are compared via a Monte Carlo simulation study in terms of their biases, root mean squared errors and their rates of obtaining reliable estimates. Recommendations are made from the simulation results and a numerical example is presented to illustrate all of the methods of inference developed here.     

Distribution of Closed Birth Intervals in a Heterogeneous Population

The probability distribution of parity-specific closed birth intervals in a heterogeneous population of women is obtained from Biswas' (1980) concept of gradually decreasing fecundabilities. The distribution of parity-specific last closed birth intervals and its moments of various orders are derived for a heterogeneous female population. Simulations are used to compare with models for a homogeneous female population with constant fecundability. The consideration of heterogeneity allows a better fit for empirical closed birth intervals.     

离心叶轮流道型线对气固两相流动的影响

以实验方法对旋转离心叶轮内气固两相流动进行了研究。离心叶轮的磨损主要由叶片进口的冲击磨损和压力面的滑移磨损构成。经对实验照片的分析可知,叶轮入口颗粒径向速度的大小是造成叶轮冲击磨损的主要原因。不同流道型线叶轮的对比结果可以证明,改变流道型线能有效地叶轮抗磨损的能力。     

抗震支座在大跨度空间结构中的应用

介绍抗震支座在大跨度空间结构广州体育馆工程中的应用．广州体育馆屋顶系大跨度空间钢桁架体系，采用抗震支座可以有效地减小钢桁架的内力．     

Generalized Maximum Spacing Estimation for Multivariate Observations

In this paper, the maximum spacing method is considered for multivariate observations. Nearest neighbour balls are used as a multidimensional analogue to univariate spacings. A class of information‐type measures is used to generalize the concept of maximum spacing estimators. Weak and strong consistency of these generalized maximum spacing estimators are proved both when the assigned model class is correct and when the true density is not a member of the model class. An example of the generalized maximum spacing method in model validation context is discussed.     

贴体网格生成技术中正交性和空间疏密控制研究

在综合阐述网格生成技术对流场数值计算重要性的基础上,提出了一种非周期性叶栅流场网格的数值生成方法。该方法对任意曲线（面）边界生成正交性思想的网格具有普适性,且可以对整个区域网格的正交性进行有效的控制。此外,本文还对网格正交性和疏密分布之间的关系进行了探讨,给出了影响网格正交性的因素和改进方法。     

Birth Spacing in the Netherlands. The Effects of Family Composition, Occupation and Religion on Birth Intervals, 1820–1885

In this article, Dutch family reconstructions from the period 1820–1885 are analyst. Cox regression on birth intervals discloses that couples deliberately increased birth intervals already before the onset of the fertility transition. Spacing was not related to a targeted family size or to the sex composition of the family. Rather, the (temporary) burden of young, dependent children induced the parents to delay the next conception. Catholics and orthodox Protestants had shorter birth intervals than liberal Protestants, either because they rejected breastfeeding or because they were reluctant to experiment with birth spacing. Relatively long birth intervals were prevalent in the lowest social groups, whereas farmers and the self-employed middle class tended towards short intervals.     

偏心率对双层搅拌桨偏心搅拌槽内流场的影响

偏心搅拌大都集中在对单层桨叶搅拌槽的研究,对双层的研究很少且集中在数值模拟研究,文章利用粒子图像 测速技术对轴偏心搅拌釜内流场进行实验研究。分析了不同偏心率对搅拌槽内宏观流场的影响,探讨了桨间轴向位置 处无因次化径向和轴向速度的分布。结果表明：搅拌槽内的速度最大值并不是随着偏心距的增大而增大;当偏心率e分 别为0.1和0.2时,可以提高径向速度的分布区间;当偏心率e>0.2时,内部存在一些漩涡导致速度波动比较大,这种流 体趋势并不有利于筒体内部流体的混合。研究结果对双层桨偏心搅拌器的设计具有指导意义。     

叙事与抒情、小说与电影的众声喧哗——沈从文《菜园》的文本细读

沈从文先生的小说《菜园》是融叙事与抒情为一体的中国"诗化小说",本文运用西方叙事学理论细读《菜园》,从文中运用抒情性作品的结构元素(画面)来讲述故事入手分析其淡化的叙事结构等方面;并共时性的分析文本中时间概念的空间转化,当"玉家菜园"变成"玉家花园"时,白菜的生存意义转化为菊花旺盛的生命力,传达出作家的反抗与作家对知识的知觉和追逐,而不是文明对自然的毁灭。