Till Death Do Us Part: Marital Status and U.S. Mortality Trends, 1986 – 2000

Although the association of being married and a lower mortality rate has been well established, most previous research on marital status and mortality did not consider potential change in this relationship over time. In this study, I adopted a survey cohort perspective to examine both overall and cause‐specific mortality trends by marital status from 1986 to 2000 in the United States. On the basis of data from the National Health Interview Survey‐Longitudinal Mortality Follow‐up (N = 517,314), I found that mortality generally decreased or remained stable for the married from the 1986 to 2000 NHIS cohort, except for diabetes deaths. There is evidence showing divergent mortality trends between the married and unmarried, especially the widowed. Race and gender variations are examined.     

对设备新度系数的讨论

设备新度系数是反映设备更新速度的指标之一，本文主要研究并提出了如何提高设备新度系数以及对设备新度系数进行定量控制的方法．     

甘肃省出生缺陷1：2配对病例对照研究

为了解甘肃省出生缺陷死亡率及易患因素,为“甘肃省出生缺陷干预工程”项目的实施提供可干预的核心因素。根据甘肃地理特点及经济状况,按随机分层整群抽样方法,抽取了4个县,共42个乡为调查点。结果显示四县市婴儿总死亡率15.8‰(98例),出生缺陷死亡率7.7‰。甘肃省出生缺陷前五位的致病因素依次为:母亲孕早期接触农药史;母亲孕前一月服药史;母亲孕期接触农药史;母亲孕早期感染史;既往流产史。     

Optimizing inventory and marketing policy for non-instantaneous deteriorating items with generalized type deterioration and holding cost rates

This paper considers an inventory system with non-instantaneous deteriorating item in which demand rate is a function of advertisement of an item and selling price. This paper aids the retailer in maximizing the total profit by determining optimal inventory and marketing parameters. In contrast to previous inventory models, an arbitrary holding cost rate and arbitrary deterioration rate have been incorporated to provide general framework to the model. First, a mathematical model is formulated and then some useful theoretical results have been framed to characterize the optimal solutions. The necessary and sufficient conditions for the existence and uniqueness of the optimal solutions are also derived. An algorithm is designed to find the optimum solutions of the proposed model. Numerical examples are included to illustrate the algorithmic procedure and the effects of key parameters are studied to analyze the behavior of the model.     

Uncertain Benefits Estimates for Reductions in Fine Particle Concentrations

The Environmental Protection Agency's (EPA's) estimates of the benefits of improved air quality, especially from reduced mortality associated with reductions in fine particle concentrations, constitute the largest category of benefits from all federal regulation over the last decade. EPA develops such estimates, however, using an approach little changed since a 2002 report by the National Research Council (NRC), which was critical of EPA's methods and recommended a more comprehensive uncertainty analysis incorporating probability distributions for major sources of uncertainty. Consistent with the NRC's 2002 recommendations, we explore alternative assumptions and probability distributions for the major variables used to calculate the value of mortality benefits. For metropolitan Philadelphia, we show that uncertainty in air quality improvements and in baseline mortality have only modest effects on the distribution of estimated benefits. We analyze the effects of alternative assumptions regarding the value of reducing mortality risk, whether the toxicity is above or below the average for fine particles, and whether there is a threshold in the concentration‐response relationship, and show these assumptions all have large effects on the distribution of benefits.     

基于多阶段随机规划模型的国债动态积极投资策略

本文提出国债组合投资的多阶段随机规划模型,导出基于未来利率市场不确定信息的具备动态调整特点的国债组合主动投资策略。该模型采用基于利率水平、斜率和曲率"三位一体"的离散情景树刻画未来利率期限结构动态演化过程,其中特别考虑了广义货币供给变动的影响;通过最小化国债组合收益的条件风险价值,对国债组合进行主动动态调整;同时兼顾国债投资安全性、流动性和收益性等要求,实现了国债组合投资管理中利率风险规避和收益能力的有效匹配。实证研究表明,与传统久期配比免疫模型相比,该模型确定的最优策略不仅能够为国债组合提供更强的抵御利率风险能力,而且能够稳步提升其收益空间,为金融机构实现国债投资的主动管理提供决策支持。     

Strategic technology alliance termination: An empirical investigation

There is growing consensus that overall alliance termination rates are high. However, despite this track record of termination and despite unsurpassed growth rates of strategic technology alliances, little is known about the reasons for their termination. Typically strategic alliances have been characterized as inherently instable, i.e. often involving unplanned and premature termination of the alliance by partnering firms indicating alliance failure. The literature on strategic technology alliances, however, proposes that alliance termination does not always indicate failure, but can be intended and can be a sign of strength. We examine these different perceptions by using a sample of 48 strategic technology alliances in different high-technology industries. The findings in the paper confirm that the rates of termination are rather high for strategic technology alliances. Overall, we found that in particular negative prospects about future cooperation, negative perceptions about joint benefits and the lack of a win-win situation had an impact on the decision to terminate a strategic technology alliance. Also, the fact that some companies opt only for short-term (not for long-term and renewed) cooperation seems to introduce a negative factor into the longevity of strategic technology alliances.     

Do Drivers of Small Cars Take Less Risk in Everyday Driving?

Previously reported observed data on risky everyday driving are brought together and reanalyzed in order to focus on the relation between risky driving and the size of the car being driven, as indicated by car mass. The measures of risky driving include separation between vehicles in heavy freeway traffic and speed on a two lane road. Observed seat belt use provides a third measure of driver risk. Confounding effects arising from the observed association between car mass and driver age are taken into account by segmenting the data into three driver age groups. Driver risk taking is found to increase with increasing car mass for each of these three aspects of everyday driving. The implications of these results with respect to driver fatality rates are discussed in terms of a simple model relating observed risky driving to the likelihood of involvement in a severe crash.     

Women's Scientific Employment and Family Formation: A Longitudinal Perspective

We focus here on the retention of highly qualified women scientists in science‐based employment in England and Wales. Using linked Census records from the Longitudinal Study 1971–1991 we show that women's education and employment rates in science, engineering and technology increased somewhat, although some fields show persistently low representation. We then compare retention in employing women with health‐related degrees with that of women with degrees in science, engineering and technology, showing that the latter group has markedly lower retention rates. Those who stay on in science‐based employment have children later than other types of graduate and their rates of non‐motherhood are higher. Four‐fifths of women in health‐related occupations were mothers, compared to only two‐fifths in science, engineering and technology. Our findings have implications for policymakers who wish to make best use of the knowledge base: attention should be paid to retention, as well as the more usual focus on qualifications and recruitment. The findings also suggest the potential for institutionally based theories to explain why highly qualified women have such low retention rates in science‐based employment.     

Risk premiums in asset prices and returns

We review recent research on time-varying risk premiums, including attempts to explain rejections by baillie and others of the unbiasedness hypothesis. Using spot and forward foreign exchange rates we discuss the evidence for time-varying risk premiums, relate it to general equilibrium theories of asset pricing, and describe the artificial economy methodology.