常见寿命数据类型及生命表的编制方法

生命表是描述种群死亡过程的有用工具,介绍了4种常见的寿命数据类型;寿终数据,右删失数据,左删失数据和区间型数据特征及其相应的数据分析处理方法即生命表法,乘积限估计和Turbull估计法,对生命表法和乘积限估计法应用上的特点进行了比较,同时还对特殊的寿命数据类型－－截断数据做了简要介绍。     

动态生命表寿命数收集与处理过程中常见问题的探讨

种群动态生命是研究野生动物存活过程的有用工具,而其可靠性则依赖于生命数据收集与处理过程中的正确性。章就野生动物动态生命表收集和处理过程中常见的右删失数据处理问题、个体死亡时间估计、同生群初始值N0估计以及早期死亡数据的估算问题提出了一点建议和讨论。     

删失数据下的非参数分位回归

本文结合分位回归方法与非参数模型,对删失数据下的非参数分位回归模型的估计方法以及算法进行研究,运用质量再分配加权思想(Redistribution-of-Mass)将删失参数模型的估计方法推广到非参数领域,同时,出于充分利用数据信息的考虑,本文综合逆概率加权和质量再分配加权思想,在估计过程中采用这两类权数,提出了一种新的局部综合加权估计.通过蒙特卡洛模拟可知,在固定删失情形下,无论有无异方差存在,质量再分配加权估计有显著的优势;而在随机删失情形下,逆概率与质量再分配综合加权估计效果最好,进而验证了本文提出的估计方法的有效性和合理性.最后本文将各估计方法应用于实际数据中,实证分析的结果进一步展示了所提出估计方法的合理性.     

梅花鹿肝内门静脉系统的初步观察

以铸型技术观察了梅花鹿（Ｃｅｒｖｕｓ　ｎｉｐｐｏｎ）肝的门静脉系统。发现门静脉左支发出左外侧叶背侧静脉、左外侧叶腹侧静脉、左内侧叶外侧静脉、左内侧叶内侧静脉,尾状叶支和方叶支;右支缺如;右内侧叶静脉、右外侧叶背侧静脉、右外侧叶腹侧静脉直接由门静脉分出,尾状突静脉由右外侧叶腹侧静脉分出。梅花鹿肝如人、兔、猪、山羊、猕猴一样可分为二叶、四段,即左、右叶和左外侧叶（段）、左内侧叶（段）,右内侧叶（段）、右外侧叶（段）,尾状叶的左、右部可分别隶属于左、右叶。     

右美托咪定对老年骨质疏松合并股骨颈骨折患者术后苏醒质量、定量脑电图和谵妄的影响

摘要 目的：探讨右美托咪定（Dex）对老年骨质疏松合并股骨颈骨折患者术后苏醒质量、定量脑电图和谵妄的影响。方法：选择2016年1月-2021年3月期间我院收治的老年骨质疏松合并股骨颈骨折患者97例,将其根据随机数字表法分为对照组（48例）和Dex组（49例）,两组均行全髋关节置换术治疗,Dex组麻醉诱导前给予0.5 μg/kg Dex,对照组予以等量生理盐水,观察两组术后苏醒质量、血流动力学变化、定量脑电图频率,记录两组谵妄和麻醉不良反应发生情况。结果：与对照组相比,Dex组呼吸恢复时间、拔管时间、睁眼时间更短（P<0.05）。两组手术切皮时（T2）~术毕时（T4）时间点心率（HR）均低于麻醉前（T1）时间点,平均动脉压（MAP）均高于T1时间点,组内对比差异有统计学意义（P<0.05）。Dex组T2~T4时间点HR高于对照组对应时间点,MAP低于对照组对应时间点（P<0.05）。Dex组术后1 d左/右颞区、左/右额区δ波频率低于对照组（P<0.05）。Dex组术后1 d左/右颞区、左/右额区α1波频率高于对照组（P<0.05）。Dex组术后谵妄发生率低于对照组（P<0.05）。两组间麻醉不良反应发生率无统计学差异（P>0.05）。结论：老年骨质疏松合并股骨颈骨折患者手术期间予以Dex,可改善患者术后苏醒质量,且对血流动力学影响较小,可减轻对患者大脑额叶δ、α1波频率的影响,同时降低谵妄的发生率。     

肝硬化患者肝脏门静脉血流与肝叶萎缩之间关系的研究

目的：探讨肝硬化患者肝脏右叶、左叶体积变化,检测肝硬化患者门静脉血流情况,分析二者之间的关系,以及门静脉血流与肝功能之间关系。方法：本研究纳入54例肝硬化患者和40例正常人,采用超声多普勒方法分析这些受试者的肝脏体积和门静脉主干及左右分支的内径、血流速、流量数据,并通过静脉血检测白蛋白、胆红素、胆碱酯酶水平等评估患者肝功能水平。结果：肝硬化组平均年龄46.3岁,男性32例,其中childA级患者16例,childB级患者27例,childC级患者11例;正常对照组平均年龄41．8岁,男性24例。肝硬化组患者右左肝叶之比明显低于正常对照组（p〈0．05）,门静脉内径和血流量明显高于正常对照组（p〈0．05）．随着child分级升高,门静脉血流量也明显升高。肝硬化组门静脉右支血流量明显低于左支血流量（p〈0．05）;此外肝硬化患者门静脉右支和左支血流量之比明显低于正常人群门静脉右左支之比（p〈0．05）;而且肝硬化患者门静脉右左支血流量之比与右左肝叶具有明显的相关性与右左肝叶之比具有明显的相关性（r=0．64,p〈0．05）。结论：评估肝硬化病人门静脉血流情况,对于判断肝脏病理变化程度,评价治疗效果,以及选择治疗方案方面都具有重要的临床价值     

HBK-SPF鸭主要解剖数据的测定

目的分别测定7日龄和56日龄的HBK-SPF鸭的解剖学数据,并分析比较性别之间的差异。方法采用常规方法测定7日龄和56日龄的雌、雄HBK-SPF鸭的解剖数据,并对雌雄差异进行了统计学分析。结果在所测定的解剖数据中,不同日龄、性别之间表现差异显著性的项目不同,其中7日龄时,左肾、右肾存在性别差异,达到极显著（P〈0.01）,胫围和盲肠2存在显著性别差异（P〈0.05）;56日龄时,只有胸腺存在极显著性别差异（P〈0.01）,盲肠1和直肠差异显著（P〈0.05）,其它解剖数据在雌雄之间差异不显著。结论不同日龄的HBK-SPF鸭的解剖数据和脏器参数存在性别差异。     

树鼩解剖数据的测定与分析

解剖数据是实验动物主要的生物学特性指标。该文对实验室驯养树鼩(7～9月龄)的体尺、骨骼、乳头、肠道及脏器重量与系数等解剖学数据进行了测定与分析。31项解剖数据测量结果显示雌、雄个体间体高、右耳宽、回肠及结肠差异显著(P<0.05),体斜长、胸深、躯干长、左右两前肢长、右后肢长、左右两侧耳长、左耳宽、龙骨长、左右两侧胫长、十二指肠及空肠长等差异极显著(P<0.01)。以体长为因变量,尾长、躯干长、左前肢长、右前肢长、左后肢长及右后肢长等为自变量作逐步回归分析,回归方程为:体长=13.90+尾长×0.16。37项脏器及系数测定结果:雌雄间比较,体重、心、肺、脾、左肾、右肾、膀胱、左海马、右海马、左颌下腺、左甲状腺、右甲状腺重量差异极显著(P<0.01)。小肠、右颌下腺、左肾上腺之间差异显著(P<0.05);心、肺、胃、膀胱、小肠、大肠、脑、右海马、左肾上腺系数雌雄间差异极显著(P<0.01)。右肾、左海马、左颌下腺、右肾上腺、左右两侧甲状腺系数之间达到了显著性水平(P<0.05)。以动物体重为因变量,以主要脏器指标:心脏、肺、肝、脾、左肾、右肾、脑为自变量,作逐步回归分析,回归方程为:体重=62.73+左肾×79.213+心脏×24.09。实验室驯养树鼩不同性别对体尺、脏器及系数、肠道等解剖数据有一定影响,为树鼩实验动物化及人类疾病动物模型研究提供基础数据。     

基于神经网络原理的荧光寿命成像研究

荧光寿命成像技术(fhlorescence lifetime imaging,FLIM)是一种新颖且功能强大的、能用于复杂生物组织和细胞结构与功能分析的生物组织成像技术。传统的时域荧光寿命成像数据分析方法,由于没有考虑荧光分子团之间以及他们与周围环境的相互作用,可能导致复杂的连续分布荧光寿命这一实际情况,因此对生物组织中自发荧光发光强度衰减过程的实验数据拟合效果欠佳。文章提出利用人工神经网络(artificial neural network,ANN)原理拟合算法来计算生物荧光分子团衰减动力过程,该方法能有效地建立生物荧光分子团衰减动力过程的非线性模型,并且具有处理非线性模型能力强、鲁棒性好、拟合精度高和所需计算时间少等优点。通过计算证明,相对于单参量指数与多参量指数衰减函数,这种数据拟合方法对于某些荧光分子团的多槽基面效价测定样品(multi-well plate assays)的数据有更好的一致性和更小的计算量。同时在文章中讨论了将该拟合算法应用于荧光寿命成像的前景。     

一雄性灰鹤胃的血液供应

用血管铸型法对一只因伤致死的雄性灰鹤胃的血供进行铸型观察,结果显示,灰鹤的胃动脉均由腹腔动脉分出,腺胃由腺胃背侧动脉和腺胃腹侧动脉供应营养,肌胃由胃左动脉、胃右动脉和肌胃背侧动脉供应营养。腺胃的静脉有腺胃腹侧静脉、胃凹腹侧静脉和腺胃背侧静脉,分别经左（腺胃腹侧静脉和胃凹腹侧静脉）、右（腺胃背侧静脉）肝门静脉回流;肌胃的静脉有胃左静脉、胃右静脉和胃背侧静脉,分别经左（胃左静脉）、右（胃右静脉和肌胃背侧静脉）肝门静脉回流。此外本文将灰鹤胃的血供与其它动物的进行了比较。     

Demographic window to aging in the wild: constructing life tables and estimating survival functions from marked individuals of unknown age

Summary We address the problem of establishing a survival schedule for wild populations. A demographic key identity is established, leading to a method whereby age-specific survival and mortality can be deduced from a marked cohort life table established for individuals that are randomly sampled at unknown age and marked, with subsequent recording of time-to-death. This identity permits the construction of life tables from data where the birth date of subjects is unknown. An analogous key identity is established for the continuous case in which the survival schedule of the wild population is related to the density of the survival distribution in the marked cohort. These identities are explored for both life tables and continuous lifetime data. For the continuous case, they are implemented with statistical methods using non-parametric density estimation methods to obtain flexible estimates for the unknown survival distribution of the wild population. The analytical model provided here serves as a starting point to develop more complex models for residual demography, i.e. models for estimating survival of wild populations in which age-at-entry is unknown and using remaining information in randomly encountered individuals. This is a first step towards a broad new concept of 'expressed demographic information content of marked or captured individuals'.     

Cause‐Specific Cumulative Incidence Estimation and the Fine and Gray Model Under Both Left Truncation and Right Censoring

Summary The standard estimator for the cause‐specific cumulative incidence function in a competing risks setting with left truncated and/or right censored data can be written in two alternative forms. One is a weighted empirical cumulative distribution function and the other a product‐limit estimator. This equivalence suggests an alternative view of the analysis of time‐to‐event data with left truncation and right censoring: individuals who are still at risk or experienced an earlier competing event receive weights from the censoring and truncation mechanisms. As a consequence, inference on the cumulative scale can be performed using weighted versions of standard procedures. This holds for estimation of the cause‐specific cumulative incidence function as well as for estimation of the regression parameters in the Fine and Gray proportional subdistribution hazards model. We show that, with the appropriate filtration, a martingale property holds that allows deriving asymptotic results for the proportional subdistribution hazards model in the same way as for the standard Cox proportional hazards model. Estimation of the cause‐specific cumulative incidence function and regression on the subdistribution hazard can be performed using standard software for survival analysis if the software allows for inclusion of time‐dependent weights. We show the implementation in the R statistical package. The proportional subdistribution hazards model is used to investigate the effect of calendar period as a deterministic external time varying covariate, which can be seen as a special case of left truncation, on AIDS related and non‐AIDS related cumulative mortality.     

An additive‐multiplicative mean residual life model for right‐censored data

Many studies have focused on determining the effect of the body mass index (BMI) on the mortality in different cohorts. In this article, we propose an additive‐multiplicative mean residual life (MRL) model to assess the effects of BMI and other risk factors on the MRL function of survival time in a cohort of Chinese type 2 diabetic patients. The proposed model can simultaneously manage additive and multiplicative risk factors and provide a comprehensible interpretation of their effects on the MRL function of interest. We develop an estimation procedure through pseudo partial score equations to obtain parameter estimates. We establish the asymptotic properties of the proposed estimators and conduct simulations to demonstrate the performance of the proposed method. The application of the procedure to a study on the life expectancy of type 2 diabetic patients reveals new insights into the extension of the life expectancy of such patients.     

A Stratified Product Limit Estimator for the Follow-up Study in Cardio-Thoracic Surgery

We propose a stratified product limit estimator and compare the asymptotic results with those of the unstratified version. When the censoring mechanisms are unequal for different strata, the unstratified version may overestimate the total survival rate of a heterogeneous population. A numerical example in cardiac surgery is examined to demonstrate that this situation does occur in real applications. This overestimation also can be elucidated heuristically by some redistribution schemes for the censored data.     

A general method for constructing increment-decrement life tables that agree with the data

A general method for making increment-decrement life tables is presented. The method involves the finding of probabilities of transition between states, graduated to small intervals of time and age, that are consistent with (i.e., can reproduce) the data, whether the data consist of central age-state specific rates, or some other feature, such as state distributions of a real cohort. The method is then illustrated with a fetal loss life table.     

The Analysis of Life Table and Follow-up Data with Covariates Using Poisson Regression Model

The Poisson regression model for the analysis of life table and follow-up data with covariates is presented. An example is presented to show how this technique can be used to construct a parsimonious model which describes a set of survival data. All parameters in the model, the hazard and survival functions are estimated by maximum likelihood.     

A general theory of life table construction and a precise abridged life table method

"In this paper we lay the foundation of life table construction by unifying the existing life table methods. We also present a new method of constructing current (period) abridged life tables.... The development includes (1) a careful formulation and computation of age-specific death rates, (2) derivation of a new set of formulas for computing the survivorship function from the observed age-specific death rates and populations, (3) estimation of the main life table functions by spline interpolation, integration and differentiation, and (4) use of a quadratic and a Gompertz function to close the life table.... The method is illustrated with construction of abridged life tables using Canadian data."     

Missing Data and the Mixtures of Discrete and Continuous Random Variables

In many practical applications we deal with a problem of estimation of a density function of a vector x some components of which are discrete, while the remaining ones are continuous. Among many models that can be used in this case the most useful are the location model and the kernel model. The problem arises when the observed data contain missing values i.e. on some individuals some of the variables have not been observed with no particular pattern of missingness. An application of the EM algorithm will allow us to estimate the parameters of the location model from incomplete data. The method is described in Section 2. In Section 3 some suggestions how to deal with incompleteness when the kernel model is used are made. Finally, Section 4 contains an example.