A Model for Setting Performance Objectives for Salmonella in the Broiler Supply Chain

A stochastic model for setting performance objectives for Salmonella in the broiler supply chain was developed. The goal of this study was to develop a model by which performance objectives for Salmonella prevalence at various points in the production chain can be determined, based on a preset final performance objective at the end of the processing line. The transmission of Salmonella through the broiler production chain was modeled. The prevalence at flock level was calculated from the measured prevalence at sample level. The transmission model is based on data on the occurrence of Salmonella collected in the Dutch broiler production chain during several years. The developed model can be used by policymakers and industry to determine economically and politically acceptable performance objectives for various points of the production chain and to draw conclusions about which interventions are most appropriate.     

微波管CAD技术进展

传统的经验设计方法很难综合性地进一步提高微波管的功率、带宽、增益、效率及非线性特性等性能,高精度的微波管CAD模拟软件是改进设计,提高性能的主要手段。该文综述了微波管CAD技术的国内外研究进展,介绍了微波管CAD软件的主要分类及代表性软件,特别是我国自主研发的二维宽带大功率行波管CAD集成环境软件系统及三维微波管模拟器套装。展望了微波管CAD技术的发展前景,对我国自主开发微波管CAD软件提出了一些建议。     

Parental Work Schedules and Children's Cognitive Trajectories

Previous work has shown an association between mothers' nonstandard work schedules and children's well-being. We built on this research by examining the relationship between parental shift work and children's reading and math trajectories from age 5/6 to 13/14. Using data (N=7,105) from the National Longitudinal Survey of Youth and growth curve modeling, we found that children's math and reading trajectories were related to parents' type of nonstandard shifts (i.e., evening, night, or variable). We found that having a mother who worked more years at a night shift was associated with lower reading scores, having a mother work more years at evening or night shifts was associated with reduced math trajectories, and having a father work more years at an evening shift was associated with reduced math scores. Mediation tests suggest that eating meals together, parental knowledge about children's whereabouts, and certain after-school activities might help explain these results.     

数据库资源空间中分片技术的研究

在资源空间模型理论的基础上结合分布式的特征，通过资源空间的操作机制来实现对一个资源空间进行分片可以有三种基本分片方式：基于坐标的资源空间分片、基于坐标轴的资源空间分片和混合型资源空间分片。     

高等数学教学改革的探讨

文章认为现行高等数学教学中存在一些突出问题:课程基本目标与实际教学之间的矛盾;课时减少带来的矛盾;教育目标与应试式教学之间的矛盾;理论知识与应用之间的矛盾;现代化教学手段与部分教师惰性之间的矛盾等。同时针对上述问题提出了改革措施。     

满文元音词尾形体多样性研究

形体力学是满文研究的非常重要的内容之一,惯性延伸是满文形体运动的重要规律。由此形成的上形体决定论是元音词尾形体多样性形成的内在因素。     

Survival of Staphylococcus aureus ATCC 13565 in Intermediate Moisture Foods is Highly Variable

Staphylococcus aureus is a gram-positive, enterotoxin-producing coccus. It is a hardy organism and known to survive over a wide range of water activities, pH values, and temperatures. The objective of this study was to model the survival or gradual inactivation of S. aureus ATCC 13565 in intermediate moisture foods (IMFs). Various initial concentrations (approximately 10(1), 10(2), 10(3), and 10(4) CFU/g) were used to inoculate three different IMFs (beefsteak, bread, and chicken pockets). Viable counts were determined up to 60 days using tryptic soy agar. Inoculum size did not influence the survival or gradual inactivation of S. aureus in these foods. The rate of change (increase or decrease) in log CFU/day was calculated for every consecutive pair of data points and by linear regression for each inactivation curve. Both consecutive pair and linear regression rates of change were fit to logistic distributions (with parameters alpha and beta) for each food. Based on the distribution parameters, survival or gradual inactivation of S. aureus was predicted by computer simulation. The simulations indicated an overall decline in S. aureus population over time, although a small fraction of samples in the consecutive pair simulation showed a slight population increase even after 60 days, consistent with the observed data. Simulation results were compared to predictions from other computer models. The models of Stewart et al., were fail-safe, predicting the possibility of significant growth only after > 3,000 days. The USDA pathogen modeling program predictions were found to be fail-dangerous, predicting declines at least four times faster than observed.     

信息力学与对称化管理

在信息人的假设基础上,认为管理学是信息动力学,人在社会中的运动,是人的信息位在信息场空间中的变动。由于对称性支配的相互作用,所以在信息场空间的信息相互作用中存在着各种层次上的对称性机制,因而管理在本质上是对称化管理。     

创新意识与创新精神的激发和培养

创新创造是人类发展和进步的灵魂,是一个民族能够屹立于世界民族之林的重要特征.文章从创新创造是人类发展进步的需要,是人类具有的潜在本性,以及从问题提出、思考与学习、社会实践等方面展开创新意识与创新精神激发、培养等方面的探讨.