Evaluation of the parameters of su by rational fractions

A rational fraction approximation is given for a function of one of the parameters defining Johnson's S_UError assessment for a segment of the domain of validity shows remarkable accuracy.     

A model with long-term survivors: negative binomial Birnbaum-Saunders

Abstract

We propose a cure rate survival model by assuming that the number of competing causes of the event of interest follows the negative binomial distribution and the time to the event of interest has the Birnbaum-Saunders distribution. Further, the new model includes as special cases some well-known cure rate models published recently. We consider a frequentist analysis for parameter estimation of the negative binomial Birnbaum-Saunders model with cure rate. Then, we derive the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes. We illustrate the usefulness of the proposed model in the analysis of a real data set from the medical area.     

Sums of powers of binomial coefficients

An asymptotic series for sums of powers of binomial coefficients is derived, the general term being defined and usable with a computer symbolic language. Sums of squares of coefficients in the symmetric case are shown to have a link with classical moment problems, but this property breaks down for cubes and higher powers. Problems of remainders for the asymptotic series are mentioned. Using the reflection formula for I'(.), a continuous form for a binomial function is set up, and this becomes oscillatory outstde the usual range. A new contmued fraction emerges for the logarithm of an adjusted sum of binomial squares. The note is a contribution to the problem of the interpretation of asymptotic series and processes for their convergence acceleration.     

论可持续发展教育的必要性和紧迫性

目前,针对人类所面临的人口、资源、环境与可持续发展等问题,对学生进行可持续发展教育是必要的.它是素质教育和教育、教学深入改革的具体体现,有助于学生理解、宣传和自觉执行国家的各种政策、法规;树立正确的自然观和生态观以及担负历史的重任.     

Fisher information in randomly sampled sib pairs and extremely discordant sib pairs in genetic analysis for a quantitative trait locus

The conditional mixture likelihood method using the absolute difference of the trait values of a sib pair to estimate genetic parameters underlies commonly used method in linkage analysis. Here, the statistical properties of the model are examined. The marginal model with a pseudo-likelihood function based on a sample of the absolute difference of sib-traits is also studied. Both approaches are compared numerically. When genotyping is much more expensive than screening a quantitative trait, it is known that extremely discordant sib pairs provide more powerful linkage tests than randomly sampled sib pairs. The Fisher information about genetic parameters contained in extremely discordant sib pairs is calculated using the marginal mixture model. Our results supplement current research showing that extremely discordant sib pairs are powerful for the linkage detection by demonstrating they also contain more information about other genetic parameters.     

关于Diophantine方程ax（x＋1）…（x＋z）=y（y＋1）…（y＋z）

设a是大于1的正整数.该文运用Pell方程的基本性质证明了：当a是平方数时,方程ax（x＋1）…（x＋z）=y（y＋1）…（y＋z）仅有有限多组正整数解（x,y,z）适合y-x=2;当a是非平方数时,该方程有无穷多组正整数解（x,y,z）适合y-x=2.     

关于真分式的部分分式分解

给出了把真分式分解为部分分式之和的一个简便方法。     

Intake fraction for multimedia pollutants: a tool for life cycle analysis and comparative risk assessment.

We employ the intake fraction (iF) as an effective tool for expressing the source-to-intake relationship for pollutant emissions in life cycle analysis (LCA) or comparative risk assessment. Intake fraction is the fraction of chemical mass emitted into the environment that eventually passes into a member of the population through inhalation, ingestion, or dermal exposure. To date, this concept has been primarily applied to pollutants whose primary route of exposure is inhalation. Here we extend the use of iF to multimedia pollutants with multiple exposure pathways. We use a level III multimedia model to calculate iF for TCDD and compare the result to one calculated from measured levels of dioxin toxic equivalents in the environment. We calculate iF for emissions to air and surface water for 308 chemicals. We correlate the primary exposure route with the magnitudes of the octanol-water partition coefficient, Kow, and of the air-water partitioning coefficient (dimensionless Henry constant), Kaw. This results in value ranges of Kow and Kaw where the chemical exposure route can be classified with limited input data requirements as primarily inhalation, primarily ingestion, or multipathway. For the inhalation and ingestion dominant pollutants, we also define empirical relationships based on chemical properties for quantifying the intake fraction. The empirical relationships facilitate rapid evaluation of many chemicals in terms of the intake. By defining a theoretical upper limit for iF in a multimedia environment we find that iF calculations provide insight into the multimedia model algorithms and help identify unusual patterns of exposure and questionable exposure model results.     

Integrating risk assessment and life cycle assessment: a case study of insulation.

Increasing residential insulation can decrease energy consumption and provide public health benefits, given changes in emissions from fuel combustion, but also has cost implications and ancillary risks and benefits. Risk assessment or life cycle assessment can be used to calculate the net impacts and determine whether more stringent energy codes or other conservation policies would be warranted, but few analyses have combined the critical elements of both methodologies In this article, we present the first portion of a combined analysis, with the goal of estimating the net public health impacts of increasing residential insulation for new housing from current practice to the latest International Energy Conservation Code (IECC 2000). We model state-by-state residential energy savings and evaluate particulate matter less than 2.5 microm in diameter (PM2.5), NOx, and SO2 emission reductions. We use past dispersion modeling results to estimate reductions in exposure, and we apply concentration-response functions for premature mortality and selected morbidity outcomes using current epidemiological knowledge of effects of PM2.5 (primary and secondary). We find that an insulation policy shift would save 3 x 10(14) British thermal units or BTU (3 x 10(17) J) over a 10-year period, resulting in reduced emissions of 1,000 tons of PM2.5, 30,000 tons of NOx, and 40,000 tons of SO2. These emission reductions yield an estimated 60 fewer fatalities during this period, with the geographic distribution of health benefits differing from the distribution of energy savings because of differences in energy sources, population patterns, and meteorology. We discuss the methodology to be used to integrate life cycle calculations, which can ultimately yield estimates that can be compared with costs to determine the influence of external costs on benefit-cost calculations.     

论中国派生诉讼中的原告资格

派生诉讼作为现代公司法中一项重要制度,自引入中国公司立法后,其中的原告资格限定问题便引起学界关注,亦引发诸多学者讨论,合理确定派生诉讼的原告股东资格是充分发挥派生诉讼制度的价值功能,有效预防股东滥诉的重要环节。通过从派生诉讼中原告股东诉权与原告资格限定的概念阐述入手,提出派生诉讼的原告股东诉权是以股东权为实体基础,以法律的直接规定或承认为程序的依据。在分析了中国派生诉讼原告资格的相关立法基础上,针对其中存在的缺陷就股东类型、持股比例、持续持股时间以及原告股东在提起诉讼时须具有的主观要件四个方面提出完善建议。