On Bartlett correction of empirical likelihood for regularly spaced spatial data

Bartlett correction constitutes one of the attractive features of empirical likelihood because it enables the construction of confidence regions for parameters with improved coverage probabilities. We study the Bartlett correction of spatial frequency domain empirical likelihood (SFDEL) based on general spectral estimating functions for regularly spaced spatial data. This general formulation can be applied to testing and estimation problems in spatial analysis, for example testing covariance isotropy, testing covariance separability as well as estimating the parameters of spatial covariance models. We show that the SFDEL is Bartlett correctable. In particular, the improvement in coverage accuracies of the Bartlett‐corrected confidence regions depends on the underlying spatial structures. The Canadian Journal of Statistics 47: 455–472; 2019 © 2019 Statistical Society of Canada     

河北省电子认证发展现状及对策建议

电子认证是保障网络及信息安全的重要手段。通过对河北省电子认证工作现状、取得的成绩和存在问题进行深入剖析,提出创新政府监管,加强人力、物力投入,鼓励开展跨省、跨境互认,推动电子认证服务创新升级,开展跨地区、跨行业电子认证协同,共建全国性密码与密钥基础设施等发展建议。     

市场分割、政企关系与异地市场拓展

中国的市场仍旧存在某种程度的分割，如何突破这种市场分割到异地拓展市场是企业要考虑的现实问题。以前的研究主要是从省级层面或国家层面进行宏观分析。文章创新地从政企关系视角入手来考察市场分割情形下微观层面的企业异地市场拓展，也是首先把市场分割（和异地市场）分为省内（本市外）市场、省外市场和海外市场三个不同层面来研究的论文。用世界银行的调查数据从微观企业个体层面检验了企业异地市场拓展的可能。实证研究结果发现，市场分割确实阻碍了企业异地市场拓展，但这仅限于省内市场而不是省外市场。此外，市场分割是有方向性的，从地方保护主义严重的市场里走出来的企业更容易拓展异地市场，但此结论仅适用于国内市场拓展而不适用于海外市场拓展。良好的政企关系是有利于企业异地市场拓展的，但仅限于省外市场，对省内市场以及海外市场是无效的。文章解释了其中的原因，并分析了对于企业实践的启示。     

Where college students look for vaping information and what information they believe

Abstract

Objective: This convergent mixed methods study examined how information sources influence college students’ beliefs and knowledge about vaping. Participants: College students either completed a survey (n?=?522; January–April, 2016) or were interviewed (n?=?33; 2015–2016). Methods: College students completed an online survey asking ‘where’ students had heard about e-cigarette and ‘what’ they had heard. Responses were quantified and a chi-square analysis was conducted. Additional college student e-cigarette users were interviewed about the credibility of information sources. Thematic analysis was conducted with the coded interviews. Results: There was a significant relationship between information sources for e-cigarettes (social sources, media, advertising, education/research) and the messages they recalled. Friends who vaped and e-cigarette users were the most credible information sources. Confirmation bias and scientific impotence bias characterized assessment of e-cigarette information. Conclusions: Health education specialists working on college campuses should provide accurate information via communication channels most unitized by college students.     

Negotiating Accessibility for Electronic Resources

Abstract

Accessibility of library electronic resources is a must. Its importance derives from professional ethics of librarianship, rising total costs of acquisition, and mounting legal challenges to colleges and universities that fail to provide resources accessible to users with disabilities. Library staff are responsible for ensuring the accessibility of vendor-licensed eresources. This column reviews the accessibility clauses of nine model license agreements for electronic resources. It describes terms that should go into an optimal accessibility clause and creates a composite model clause. It also provides guidance for library staff seeking to negotiate stronger accessibility language into vendor license agreements. Finally, it addresses the impact of accommodation requests on the total cost of acquiring library eresources, concluding with a call to redouble efforts to advocate for greater accessibility and educate both vendors and library staff about its importance.     

电子校务在地方高校考务管理中的应用现状及对策

电子校务是国家电子政务建设的重要组成部分，是学校应用现代信息化通信技术、借助互联网对管理和服务进行的优化和创新，电子校务在高校中的应用虽然取得了一定的成效，作为教务管理模块中的考务管理却鲜有被涉及。课程考试是我国高校教务管理工作中的一项重要工作，考务管理则是保证对学生进行有效考核的基础。因此，如何利用先进管理理念和信息化技术手段对考务管理模式进行优化，提高高校人才培养质量，已成为高校亟待研究、解决的问题。     

教育时空拓展:教师专业成长的机遇与挑战

随着人类文明的进步、社会的发展以及信息技术的普及，教育时间和空间得到迅速拓展。教育时空拓展正如一把双刃剑，给教育活动的实施带来机遇的同时也带来了挑战。教师作为教育活动的主要组织者和实施者，在享受机遇的同时也要迎接教育时空拓展所带来的挑战。通过分析教育时空拓展的内涵与表征，发现教师专业成长正处在社会化、终身化与数字化的发展大潮中，因此教师要充分利用好教育时空拓展带来的机遇，同时慎重应对由此面临的挑战，不断提高应变能力，以促进教师专业成长和教育事业的发展。     

Document Delivery as a Supplement or Replacement for Serial Subscriptions

Abstract

Increasing serials costs and shrinking budgets present challenges for academic libraries to continue providing sufficient access to scholarly articles. Rapid document delivery services can serve as an effective means to fill the gap caused by serials cancellations. This column examines several of the existing document delivery service providers and addresses issues involved in their implementation.     

Propensity score prediction for electronic healthcare databases using super learner and high-dimensional propensity score methods

ABSTRACT

The optimal learner for prediction modeling varies depending on the underlying data-generating distribution. Super Learner (SL) is a generic ensemble learning algorithm that uses cross-validation to select among a ‘library’ of candidate prediction models. While SL has been widely studied in a number of settings, it has not been thoroughly evaluated in large electronic healthcare databases that are common in pharmacoepidemiology and comparative effectiveness research. In this study, we applied and evaluated the performance of SL in its ability to predict the propensity score (PS), the conditional probability of treatment assignment given baseline covariates, using three electronic healthcare databases. We considered a library of algorithms that consisted of both nonparametric and parametric models. We also proposed a novel strategy for prediction modeling that combines SL with the high-dimensional propensity score (hdPS) variable selection algorithm. Predictive performance was assessed using three metrics: the negative log-likelihood, area under the curve (AUC), and time complexity. Results showed that the best individual algorithm, in terms of predictive performance, varied across datasets. The SL was able to adapt to the given dataset and optimize predictive performance relative to any individual learner. Combining the SL with the hdPS was the most consistent prediction method and may be promising for PS estimation and prediction modeling in electronic healthcare databases.