论信息技术条件下学习文化的再造

信息技术条件下学生的学习,实质是学生在与技术与生活相接触的过程中,创造和建构着个人意义的理解,即学生在与不同层次的文化进行互动。信息技术条件下学习文化的再造应以建构主义理论、人的主体性理论、活动理论、学习环境理论为基础,注重学习情境、学习活动、学习资源的设计。     

我国上市公司盈余管理行为的实证分析

我国证券市场存在较为严重的盈余管理现象.针对该现象,本文从盈余管理动机出发,分析我国上市公司盈余管理的行为特征.本文采用管理后盈余分布法,研究了我国上市公司2001年至2003年净资产收益率(ROE)的分布特征,发现我国上市公司仍然存在很强的盈余管理动机,而且我国上市公司盈余管理的行为受到政府监管的影响.最后,本文在实证研究的基础上提出了治理盈余管理的几点建议.     

网络拟古世情小说对当下意识形态的民间再构

近年来,在网络通俗小说创作中涌现出大量的拟古世情小说。这类小说往往以宏大的故事布局和对优秀女主人公的塑造,吸引了众多阅读者的目光。这些女主人公群像,不仅反映出汉民族文化传统的审美眼光,也寄托了根源于以家族、财富为中心的社会价值期待,还与当下价值评判体系中的女性群体的自我期许相吻合。这些拟古世情小说在完成言情小说的爱情故事构形和实现娱情的休闲功能以外,也因为广大阅读群体逐渐步入或即将步入中产阶层而发生相应的变化,重新赋予女性作为稳定家庭、增长财富、养育子女、传承家风的核心力量的社会意义,她们洁身自好,对爱情专一,勇于面对困难,乐于奉献,担当责任,胸怀宽广。这些新型的“高大全”形象,表达出女性主义的新倾向：女性的成长和幸福的获得,更重要的在于女性内在的精神力量,与传统的气节、操守有关的人格因素,以及家教和门风。这使得网络平台的民间话语表达,具有更为包容传统以及融合其合理因素的价值取向,也与当下主流意识形态遥相呼应。     

Drug resistance in an age-of-infection model

ABSTRACT

In the case of a disease spreading over a time-scale comparable to the average lifetime in a host population, when the infectiousness of individuals depends on the tine since the onset of infection and when infections involve both drug-sensitive and drug-resistant strains of a pathogen, resistance may develop during the treatment of drug-sensitive strains. If increasing the treatment rate reduces the reproduction number of the drug-sensitive strain to a value below the reproduction number of the drug-resistant strain, then the disease may persist at a boundary equilibrium where only drug-resistant infection is present.     

A Bayesian Model and Stochastic Exposure (Dose) Estimation for Relative Exposure Risk Comparison Involving Asbestos‐Containing Dropped Ceiling Panel Installation and Maintenance Tasks

Assessing exposures to hazards in order to characterize risk is at the core of occupational hygiene. Our study examined dropped ceiling systems commonly used in schools and commercial buildings and lay‐in ceiling panels that may have contained asbestos prior to the mid to late 1970s. However, most ceiling panels and tiles do not contain asbestos. Since asbestos risk relates to dose, we estimated the distribution of eight‐hour TWA concentrations and one‐year exposures (a one‐year dose equivalent) to asbestos fibers (asbestos f/cc‐years) for five groups of workers who may encounter dropped ceilings: specialists, generalists, maintenance workers, nonprofessional do‐it‐yourself (DIY) persons, and other tradespersons who are bystanders to ceiling work. Concentration data (asbestos f/cc) were obtained through two exposure assessment studies in the field and one chamber study. Bayesian and stochastic models were applied to estimate distributions of eight‐hour TWAs and annual exposures (dose). The eight‐hour TWAs for all work categories were below current and historic occupational exposure limits (OELs). Exposures to asbestos fibers from dropped ceiling work would be categorized as “highly controlled” for maintenance workers and “well controlled” for remaining work categories, according to the American Industrial Hygiene Association exposure control rating system. Annual exposures (dose) were found to be greatest for specialists, followed by maintenance workers, generalists, bystanders, and DIY. On a comparative basis, modeled dose and thus risk from dropped ceilings for all work categories were orders of magnitude lower than published exposures for other sources of banned friable asbestos‐containing building material commonly encountered in construction trades.     

Analysis of Regional Scale Risk of Whirling Disease in Populations of Colorado and Rio Grande Cutthroat Trout Using a Bayesian Belief Network Model

Introduction and spread of the parasite Myxobolus cerebralis, the causative agent of whirling disease, has contributed to the collapse of wild trout populations throughout the intermountain west. Of concern is the risk the disease may have on conservation and recovery of native cutthroat trout. We employed a Bayesian belief network to assess probability of whirling disease in Colorado River and Rio Grande cutthroat trout (Oncorhynchus clarkii pleuriticus and Oncorhynchus clarkii virginalis, respectively) within their current ranges in the southwest United States. Available habitat (as defined by gradient and elevation) for intermediate oligochaete worm host, Tubifex tubifex, exerted the greatest influence on the likelihood of infection, yet prevalence of stream barriers also affected the risk outcome. Management areas that had the highest likelihood of infected Colorado River cutthroat trout were in the eastern portion of their range, although the probability of infection was highest for populations in the southern, San Juan subbasin. Rio Grande cutthroat trout had a relatively low likelihood of infection, with populations in the southernmost Pecos management area predicted to be at greatest risk. The Bayesian risk assessment model predicted the likelihood of whirling disease infection from its principal transmission vector, fish movement, and suggested that barriers may be effective in reducing risk of exposure to native trout populations. Data gaps, especially with regard to location of spawning, highlighted the importance in developing monitoring plans that support future risk assessments and adaptive management for subspecies of cutthroat trout.     

80后农民工的城市就业现状与对策建议

分析了80后农民工在城市的就业特征,主要从四方面提出了对策建议:建立健全80后农民工就业的社会保障机制;改革创新80后农民工就业培训模式;为农民工塑造良好的工作环境;构建农民工双向流迁就业体系。     

Identifying Skeleton Curves in Noisy Data

This article presents a Bayesian method to reconstruct the centerline in noisy data using B-spline curves. The method is illustrated on simulated two- and three-dimensional data and is applied to recover the centerline of the colon in single photon emission computed tomography images.     

A divergence of opinion: how those involved in child and family social work are responding to the challenges of the Internet and social media

This discussion paper suggests that there is possibly a divergence of opinion taking place within the field of child and family social work and that the stated positions are influencing how practitioners identify and deal with risks and opportunities afforded by the Internet and social media. The suggested divergence is examined and the conclusion drawn is that what is taking place mirrors the fact that the introduction of any new technology inevitably brings with it division and debate. In seeking to understand the reaction to digital technology, consideration is given to a series of wider social discourses on childhood and risk, which includes the controversial notion that the profession is a harbinger of moral panic and that the management of risk has been broadened from child protection to child safety. The discussion paper concludes by calling for child and family social work practitioners to have a balanced debate that needs to be informed not only by current research but also by an open and honest discussion about personal use and an acknowledgement that there will be difficult moral and ethical questions to work through.     

Managing the process of change in residential child care: A consultancy approach

This article explores the impact of a consultancy undertaken with groups of residential child care staff within a large local authority who were experiencing considerable changes in their working environment as a result of a review of residential care structures. The authors were invited to engage directly with staff on an individual and group basis to help them work through the barriers they perceived to changing their approach to practice. The theoretical underpinning for the work was Charles Handy's [1993, Understanding Organisations (Harmondsworth, Penguin)] belief that change is more likely to have a positive outcome when staff have an investment in and contribution to the change processes. The model of change utilised within the sessions with staff was Kurt Lewin's three stages of 'unfreezing', 'change' and 'refreezing'. The consultancy raised a number of issues about the process of change and how this can be achieved within the residential child care context. In particular, it highlighted the problems of assuming that change is a linear process which can be directly controlled and managed in the flux and uncertainty which characterises this sector.