Quantifying Water Pathogen Risk in an Epidemiological Framework

Traditionally, microbial risk assessors have used point estimates to evaluate the probability that an individual will become infected. We developed a quantitative approach that shifts the risk characterization perspective from point estimate to distributional estimate, and from individual to population. To this end, we first designed and implemented a dynamic model that tracks traditional epidemiological variables such as the number of susceptible, infected, diseased, and immune, and environmental variables such as pathogen density. Second, we used a simulation methodology that explicitly acknowledges the uncertainty and variability associated with the data. Specifically, the approach consists of assigning probability distributions to each parameter, sampling from these distributions for Monte Carlo simulations, and using a binary classification to assess the output of each simulation. A case study is presented that explores the uncertainties in assessing the risk of giardiasis when swimming in a recreational impoundment using reclaimed water. Using literature-based information to assign parameters ranges, our analysis demonstrated that the parameter describing the shedding of pathogens by infected swimmers was the factor that contributed most to the uncertainty in risk. The importance of other parameters was dependent on reducing the a priori range of this shedding parameter. By constraining the shedding parameter to its lower subrange, treatment efficiency was the parameter most important in predicting whether a simulation resulted in prevalences above or below non outbreak levels. Whereas parameters associated with human exposure were important when the shedding parameter was constrained to a higher subrange. This Monte Carlo simulation technique identified conditions in which outbreaks and/or nonoutbreaks are likely and identified the parameters that most contributed to the uncertainty associated with a risk prediction.     

成功心理训练——高校学生工作的有效途径

成功心理训练是使学生得到成功体验,建立正确的奋斗目标并为之而奋斗的有效方式。成功心理训练是大学生完善自我,建立成功心理的切实途径。自我指导式学习能力的提高是大学生成功心理训练的核心目标。在学生工作中切实有效地根据大学生特点针对性地进行成功心理训练,在具体工作中贯彻成功心理教育,是高校学生工作的有创造、有实效的途径。     

Modifications of the Mack-Wolfe umbrella tests for a generalized Behrens-Fisher problem

We are concerned with testing procedures for umbrella alternatives in the k-sample location problem without making the assumption that the underlying populations have the same shape. Modifications of the Mack-Wolfe tests are proposed for the cases when the peak of the umbrella is known or unknown. The proposed procedures are exactly distribution-free when the continuous populations have the same shape. The modified test for peak-known umbrella alternatives remains asymptotically distribution-free when the continuous populations are symmetric, but not necessarily with the same shape.     

Al_（0．3）Ga_（0．7）As／GaAs超晶格在高能高温注入下的晶格损伤

用卢瑟福背散射／沟道技术研究了ＩＭｅＶＳｉ￣＋衬底加温注入Ａｌ_（０．３）Ｇａ_（０．７）Ａｓ／ＧａＡｓ超晶格和作为比较的ＧａＡｓ晶体后晶格的损伤积累与注入剂量的关系。实验结果表明，在注入剂量比较小的情况下，两种晶体都只有很轻微的损伤；动态退火过程的存在抑制了晶格损伤的积累。但在较高的注入剂量下，在几乎无损伤的表面下两种晶体中都形成了损伤埋层，且ＧａＡｓ中损伤峰处的损伤程度和损伤峰的宽度都大于Ａｌ_（０．３）Ｇａ_（０．７）Ａｓ／ＧａＡｓ超晶格中的情形，根据级联碰撞理论分析了晶体中的损伤积累过程，并从化学键相对强度差异的角度定性地解释了ＧａＡｓ和Ａｌ_（０．３）Ｇａ_（０．７）Ａｓ／ＧａＡｓ超晶格实验结果的不同。     

Comparison of experiments for a class of positively dependent random variables

Using Blackwell's definition for comparison of experiments, it is shown that some sets of positively dependent random variables are less informative than similar sets of independent random variables. It is also shown that the information content of symmetric multivariate normal random vectors with a common known variance increases as the common correlation coefficient decreases. Some results which compare members of two-parameter exponential families are also included.     

用低温显微DSC系统测定冻结食品的玻璃化转变温度

指出了现有的测量Ｔ＇ｇ方法中存在的问题，分析了低温显微ＤＳＣ（差示扫描量热法）系统测定Ｔ＇ｇ的原理，认为低温显微ＤＳＣ系统是一种能准确测量玻璃化转变温度Ｔ＇ｇ的新型仪器     

浅析我国的粮食安全问题

农业是我国国民经济的基础,粮食是基础的基础。在我们这样的大国,粮食是关系国计民生的特殊商品,随着人口增加,耕地减少,城市化进程加快,人民生活水平提高,我国的粮食安全问题日益凸现出来。文章就粮食安全新定义的内容分析了我国农业发展存在的问题及解决我国粮食安全问题应采取的政策措施。     

教学型恒压变频供水系统的研制

教学设备与实际生产设备相比 ,要求具有体积小、造价低、直观透明 ,技术领先的特点 ,从用途到制造工艺均具有其特殊性 ,须专门研究和开发。本文论述我们研制的具有网络功能的微型恒压供水系统的研制过程和使用情况。