The analysis of incomplete data using stochastic covariates

In the development of many diseases there are often associated random variables which continuously reflect the progress of a subject towards the final expression of the disease (failure). At any given time these processes, which we call stochastic covariates, may provide information about the current hazard and the remaining time to failure. Likewise, in situations when the specific times of key prior events are not known, such as the time of onset of an occult tumour or the time of infection with HIV-1, it may be possible to identify a stochastic covariate which reveals, indirectly, when the event of interest occurred. The analysis of carcinogenicity trials which involve occult tumours is usually based on the time of death or sacrifice and an indicator of tumour presence for each animal in the experiment. However, the size of an occult tumour observed at the endpoint represents data concerning tumour development which may convey additional information concerning both the tumour incidence rate and the rate of death to which tumour-bearing animals are subject. We develop a stochastic model for tumour growth and suggest different ways in which the effect of this growth on the hazard of failure might be modelled. Using a combined model for tumour growth and additive competing risks of death, we show that if this tumour size information is used, assumptions concerning tumour lethality, the context of observation or multiple sacrifice times are no longer necessary in order to estimate the tumour incidence rate. Parametric estimation based on the method of maximum likelihood is outlined and is applied to simulated data from the combined model. The results of this limited study confirm that use of the stochastic covariate tumour size results in more precise estimation of the incidence rate for occult tumours.     

隆线溞(Daphnia carinata king)的呼吸代谢测定

本文用Winkler法测定隆线溞(Caphnia carinata king)不同龄期个体的耗氧量及二幼龄个体在不同温度下的耗氧量。测得幼龄与成龄两阶段,其耗氧量分别以4.88×10~(-2)与1.695×10~(-1)的速率随体重增加而增大,耗氧率则分别随体重的增加而逐渐降低;在常温下,隆线溞耗氧量Y与温度X呈Y=3.69×10~(-3)×1.07~x的指数函数关系,由此得到,17℃—19℃是隆线搔生长速率快而耗氧量较小的最适人工培养温度。     

金融自由化浪潮下我国金融业发展对策

20世纪70年代以来,国际金融自由化的进程明显加快,金融工具不断创新,金融信息化蓬勃发展.利率市场化、放松金融管制、开放国内资本市场、加强对全球金融的统一监管成为大势所趋.文章通过国际金融自由化进程中一些规律性经验的总结及我国金融改革历程的回顾,对我国金融市场在利率、外汇及证券等业务的开放提出了建议.     

误码率与随机共振

用Maltab语言的Simulink软件，构成一面向结构，而且可以定量分析非线性双稳系统随机共振现象的计算机仿真实验系统，并对输入字符串信息的符号误码率随噪声振幅变化的实验数据进行了拟合，验证了非线性系统特有的随机共振现象的存在。     

政府法令与民间惯行:以国民政府颁行"年利20%"为中心

南京国民政府实行年利率不得超过 2 0 %的法令 ,但这一法令仅在个别地区有些微作用 ,总体来说始终处于“表达”层面 ,而无“实践”意义 ,乡村借贷在很大程度上仍受着传统惯行而非国家法律的支配 ,高利贷横行的格局一直未曾根本改变。也就是说 ,在离开高利贷农村社会经济就无法运转的历史条件下 ,仅靠一纸行政命令是不可能消灭高利贷的 ,在现代农村金融建立和健全以前 ,高利贷仍有生存和发展的空间 ,甚至与现代农村金融是相辅相成的     

对外开放形势下的利率风险管理问题研究

我国加入世贸组织后 ,利率市场化进程将加快 ,利率风险将成为我国商业银行的一种主要风险。文章在介绍西方主要的利率风险衡量技术的基础上 ,分析了对外开放形势下 ,我国商业银行利率风险产生的原因 ,并从商业银行、监管当局、金融市场三个层面提出利率风险管理的有关建议     

美元、日元、英镑的中长期汇率预测方法研究

文章运用组合预测方法对中长期汇率走势进行分析 ,并根据贝特斯 (Bates)和格朗格 (Granger)提出的组合预测方法 ,对美元兑日元、美元兑英镑的中长期汇率进行了预测 ,提出组合预测为一种较好的方法。     

客户价值模型及对企业价值影响的研究

本文在对现有客户价值组成估算方法及企业股东价值(Shareholder Value,SHV)理念的局限性进行评价和分析的基础上,提出了计算客户整个生命周期价值(Lifetime Value,LTV)的客户价值(Customer Value,CV)模型;并简要分析了客户价值对提升企业价值的促进作用。通过运用CV模型计算出更准确的FCFF,本文亦提出了新的SHV计算模型。文章最后对模型的数据获得途径进行了简要介绍。