Structural equation models for area health outcomes with model selection

Recent analyses seeking to explain variation in area health outcomes often consider the impact on them of latent measures (i.e. unobserved constructs) of population health risk. The latter are typically obtained by forms of multivariate analysis, with a small set of latent constructs derived from a collection of observed indicators, and a few recent area studies take such constructs to be spatially structured rather than independent over areas. A confirmatory approach is often applicable to the model linking indicators to constructs, based on substantive knowledge of relevant risks for particular diseases or outcomes. In this paper, population constructs relevant to a particular set of health outcomes are derived using an integrated model containing all the manifest variables, namely health outcome variables, as well as indicator variables underlying the latent constructs. A further feature of the approach is the use of variable selection techniques to select significant loadings and factors (especially in terms of effects of constructs on health outcomes), so ensuring parsimonious models are selected. A case study considers suicide mortality and self-harm contrasts in the East of England in relation to three latent constructs: deprivation, fragmentation and urbanicity.     

Additive Transformation Models for Recurrent Events

In this article, we propose a class of additive transformation models for recurrent event data, which includes the additive rates model as a special case. The new models offer great flexibility in formulating the effects of covariates on the mean function of recurrent events. Estimating equation approaches are developed for the model parameters, and asymptotic properties of the resulting estimators are established. In addition, a model checking procedure is presented to assess the adequacy of the model. The finite sample performance of the proposed estimators is examined through simulation studies, and an application to a bladder cancer study is presented.     

半线性抛物型方程解的熄灭时间

证明半线性抛物型方程柯西问题的解在一定条件之下在有限时刻熄灭 ,并在不同条件之下对解的熄灭时间分别进行估计     

流体力学新型通用函数Y的变分有限元分析

本文应用通用函数Y及其变分原理,为求解具有自由面流动问题提出了一种新方法。将物理平面变换成映象平面。在映象平面上,引出通用函数Y,并且写出关于Y的变分原理。用这个变分原理及有限元法求解自由面流动可克服边界未知的困难。文中以水坝闸门出流问题为例进行了计算,结果表明,该方法是非常有效的。     

高阶混合型周期系统的周期解

应用Ｆｏｕｒｉｅｒ分析的方法，结合一些不等式技巧得到了ｎ阶常系数带有滞后与超前偏差变元的混合型线性周期系统存在周期解的充要条件．     

非线性波动方程的孤波解及余弦周期波解

利用假设待定法,求出了非线性波动方程的具有双曲正割函数分式形式且渐近值不为零的精确孤波解和余弦函数周期波解,并分别讨论了它们的有界性,揭示了行波波速改变对钟状孤波解与余弦函数周期波解波形变化的影响.     

一阶非线性常微分方程可积类型的推广

文中提出新的四类非线性常微分方程，借助某些方法与技巧，论证了这几类方程可用积分法求解，获得的结论推广了文献中相应的结果。     

理想气体平均相对速率公式的证明

依据麦克斯韦速度分布律，证明了现行热学教科书中未予证明的关系式：．所用方法简单明了，具有普通物理的特点，对热学课教学具有一定的参考意义．     

热涨落对Josephson效应的影响

采用模拟粒子在势场中的布朗运动去讨论热涨落对小电容时Josephson效应的影响 ,得到热涨落存在时Joseph son结的电流—电压特性 ,计算结果与实验相符合     

糖酵解反应模型双曲型反应-扩散方程的稳定性和化学振荡

研究了糖酵解反应模型（修正Ｓｅｌｋｏｖ模型）双曲型反应－扩散方程的稳定性和化学振荡．与抛物型方程的结果比较表明，抛物型系统是双曲型系统当反应－扩散数增至无穷大时的特殊情况；双曲型系统不存在波速可能趋于无穷大的问题；二者的稳定性区域存在很大区别；双曲型系统更适合于用来研究糖酵解反应中的化学振荡．