网络安全浅析

文中就网络安全问题介绍了其策略、技术、功能、服务等相关内容,并说明了路由选择技术、加密技术和防火墙技术对网络安全的影响,给出了各技术的分类、主要技术特征,同时使读者对各种技术的实施应用有所了解。     

The evidence for the impact of policy on physical activity outcomes within the school setting: A systematic review

BackgroundDespite the well-established health benefits of physical activity (PA) for young people (aged 4–19 years), most do not meet PA guidelines. Policies that support PA in schools may be promising, but their impact on PA behavior is poorly understood. The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.MethodsThis systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Six databases were searched using key concepts of policy, school, evaluation, and PA. Following title and abstract screening of 2323 studies, 25 progressed to data synthesis. Methodological quality was assessed using standardized tools, and the strength of the evidence of policy impact was described based on pre-determined codes: positive, negative, inconclusive, or untested statistically.ResultsEvidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting. These were whole school PA policy, physical education, sport/extracurricular PA, classroom-based PA, active breaks/recess, physical environment, shared use agreements, active school transport, and surveillance. The bulk of the evidence was significantly positive (54%), 27% was inconclusive, 9% was significantly negative, and 11% was untested (due to rounding, some numbers add to 99% or 101%). Frequency of evidence was highest in the primary setting (41%), 34% in the secondary setting, and 24% in primary/secondary combined school settings. By policy area, frequency of evidence was highest for sport/extracurricular PA (35%), 17% for physical education, and 12% for whole school PA policy, with evidence for shared use agreements between schools and local communities rarely reported (2%). Comparing relative strength of evidence, the evidence for shared use agreements, though sparse, was 100% positive, while 60% of the evidence for whole school PA policy, 59% of the evidence for sport/extracurricular PA, 57% of the evidence for physical education, 50% of the evidence for PA in classroom, and 50% of the evidence for active breaks/recess were positive.ConclusionThe current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a “one-size-fits-all” approach and emphasizes the need to examine policy implementation to maximize translation into practice. Greater clarity regarding terminology, measurement, and methods for evaluation of policy interventions is needed.     

1953年粮食危机与统购统销政策的出台

统购统销政策的出台,与1953年粮食危机的出现、过渡时期总路线的贯彻有密切的关联。此前,中国粮食供需的总体形势虽有所缓和,但并没有根本好转。为解决大规模工业化建设对粮食的需求以及稳定物价的需要,中央政府不得不谋求新的控制粮食资源的办法。粮食危机的出现,为统购统销政策的出台提供了一个重要时机。另外,在酝酿采取统购统销政策时,中央政府一开始就把它纳入到过渡时期总路线中去,以便对城乡传统生产关系进行改造。     

清末学校体育改革的制度更新：基于政策文本的研究

晚清政府为了缓解内忧外患的紧张局面,试图透过自上而下若干领域的制度更新,以回应社会各界现实关切的同时,实现其延续江河日下王权的政治图景。作为晚清改革内容之一的学校体育,也承担着相同的现实诉求。运用文献资料法、内容分析法等研究方法,对晚清（1902－1911）学校体育改革成果—政策文本的分析后发现：（1）清末学校体育政策的类型、制定主体与政策内容较为单一;（2）形成了以权威工具为主,能力工具和象征劝告工具为补充的政策工具类型体系;（3）学校体育改革的重点是建章立制,以促进学校体育发展。     

自主可控提升军民融合企业的全要素生产率吗?——基于信息产业上市公司的研究

运用OLS、OP、LP三种方法对2011-2017年55家信息产业军民融合上市公司的全要素生产率(TFP)进行测算,并用DID、PSM-DID等多种方法对自主可控政策与企业TFP的关系进行了检验,实证结果表明：(1)军民融合企业的TFP整体上呈波动上升趋势,由2011-2012年低于其他企业发展至2017年略高于其他企业,但整体差异不大；(2)2014年以来逐渐加强的自主可控政策对于军民融合企业的TFP提升并没有显著影响,而是显著提升了企业的总市值,从而表明现阶段自主可控政策对于企业发展的深层次影响尚未完全体现。     

产业创新系统模型的构建与分析

产业创新系统研究是继技术创新理论和国家创新系统理论之后创新管理领域兴起的新兴前沿领域。本文在综合研究国内外产业创新管理优秀成果的基础上,构建了产业创新系统模型,对其结构、功能和运行机制进行了分析。     

新中国成立以来中国海外科技人才政策演变历史探析

我国的海外科技人才政策体系经历了从零散到系统的发展过程。本文系统地梳理新中国成立以来中国海外科技人才政策的历史演变脉络,并将其划分为五个阶段,继而概括了各个阶段的政策的主要特点,最后对政策演变历史给我们的启示进行了归纳总结。     

美国非正式科学教育的发展经验及对我国的启示

通过对目前美国学生的非正式科学教育发展历史演变过程的阐释与其当代特点的分析,揭示出美国非正式科学教育,已发展到以学习科学研究为基础和以政策支持为保障的成熟期。我国目前学生的非正式科学教育处于不成熟期,其改革与发展不仅需要包括科学界在内的相关部门的支持和加强相关基础研究工作,而且需要进行中国传统文化的改造、政策制定和实施过程的民主环境建设以及需要有效的评价手段和技术的完善。     

浅析媒介化生存对于我国体育产业发展的合理性建议

通过从两个层面阐述体育产业与大众传播媒介之间的行业互动,分析体育产业的媒介化趋势问题：一是“体育产业媒介依附论”,即体育产业对大众传播媒介具有依附性;二是“体育媒介论”,即体育、体育产业本身就是一种特殊的媒介,揭示出大众传播媒介与体育产业之间特殊的关系和内在联系。     

The Future of Defunct Religious Buildings: Dutch Approaches to Their Adaptive Re-use

Across the Western world, membership in the established organized churches is on the decline with a concomitant reduction in the need for churches and church halls. As redundant and unused churches are the focus of vandalism and decay, owners and heritage managers are looking for options to adaptively re-use such buildings. This article reviews the literature on the re-use of churches in the Netherlands, which has long history of innovatively addressing the problems. The options available range from re-use for religious purposes by other denominations or faiths, to community use (multi-purpose, sport, music etc.), and private use, which can be either commercial or residential. The attitudes of the community and the original property owners play a major part in successful adaptive re-use. Because of its long history, the Dutch experience in adaptive re-use of religious buildings has much to offer heritage managers in other countries faced with this emergent management issue.