中长跑运动训练对心脏收缩时间间期的影响

采用MCA-3C心脏功能综合检测仪,观察男子中长跑运动员在功率自行车上进行递增负荷运动时心脏收缩时间间期各指标的变化,并与非运动员进行比较,从而对中长跑运动员的左心功能进行系统评价。结果发现：安静及递增负荷运动过程中中长跑运动员LVET和PEP相对较长;递增负荷运动过程中,中长跑运动员心脏功能表现出优于普通大学生的心脏功能水平。     

Development and use of one-dimensional models of a golf ball

One-dimensional models of a golf ball are useful in modelling near-normal (90°) impact. The model described here has two masses connected by a non-linear spring in parallel with a non-linear damper. The behaviour of this system in collision with an infinite rigid mass is compared with the results of tests involving real golf balls. Values of the four unknown constants are found by fitting the model results, over a range of impact speeds from zero to 50 m· s -1 , to the coefficient of restitution and duration of contact found in the tests. The simplest model (Model 1) was a good fit for duration of contact over the whole range of impact speeds, but for the coefficient of restitution only at high speed (above 20 m· s -1 ). However, when used with a similar model of a flexible faced club, the simple model predicted the coefficient of restitution of the club-ball combination, determined by direct testing, quite well and as such is a useful screening tool. More complicated Models 2 and 3 fitted the rigid target coefficients of restitution better at low speed than Model 1. However, Models 2 and 3 have other disadvantages and are no better than Model 1 for high-speed impact with flexible faced clubs.     

Evaluating research and researchers by the journal impact factor: Is it better than coin flipping?

The journal impact factor (JIF) is the average of the number of citations of the papers published in a journal, calculated according to a specific formula; it is extensively used for the evaluation of research and researchers. The method assumes that all papers in a journal have the same scientific merit, which is measured by the JIF of the publishing journal. This implies that the number of citations measures scientific merits but the JIF does not evaluate each individual paper by its own number of citations. Therefore, in the comparative evaluation of two papers, the use of the JIF implies a risk of failure, which occurs when a paper in the journal with the lower JIF is compared to another with fewer citations in the journal with the higher JIF. To quantify this risk of failure, this study calculates the failure probabilities, taking advantage of the lognormal distribution of citations. In two journals whose JIFs are ten-fold different, the failure probability is low. However, in most cases when two papers are compared, the JIFs of the journals are not so different. Then, the failure probability can be close to 0.5, which is equivalent to evaluating by coin flipping.     

Impact Factors and the Central Limit Theorem: Why citation averages are scale dependent

Citation averages, and Impact Factors (IFs) in particular, are sensitive to sample size. Here, we apply the Central Limit Theorem to IFs to understand their scale-dependent behavior. For a journal of n randomly selected papers from a population of all papers, we expect from the Theorem that its IF fluctuates around the population average μ, and spans a range of values proportional to $\sigma /\sqrt{n}$, where σ² is the variance of the population's citation distribution. The $1/\sqrt{n}$ dependence has profound implications for IF rankings: The larger a journal, the narrower the range around μ where its IF lies. IF rankings therefore allocate an unfair advantage to smaller journals in the high IF ranks, and to larger journals in the low IF ranks. As a result, we expect a scale-dependent stratification of journals in IF rankings, whereby small journals occupy the top, middle, and bottom ranks; mid-sized journals occupy the middle ranks; and very large journals have IFs that asymptotically approach μ. We obtain qualitative and quantitative confirmation of these predictions by analyzing (i) the complete set of 166,498 IF & journal-size data pairs in the 1997–2016 Journal Citation Reports of Clarivate Analytics, (ii) the top-cited portion of 276,000 physics papers published in 2014–2015, and (iii) the citation distributions of an arbitrarily sampled list of physics journals. We conclude that the Central Limit Theorem is a good predictor of the IF range of actual journals, while sustained deviations from its predictions are a mark of true, non-random, citation impact. IF rankings are thus misleading unless one compares like-sized journals or adjusts for these effects. We propose the Φ index, a rescaled IF that accounts for size effects, and which can be readily generalized to account also for different citation practices across research fields. Our methodology applies to other citation averages that are used to compare research fields, university departments or countries in various types of rankings.     

大学图书馆成效评估及其指标体系构建探索

大学图书馆成效评估是对用户在接触图书馆所提供的资源、服务和活动之后所发生的改变进行评估。绩效评估关注图书馆投入与产出的效率,成效评估关注图书馆服务的影响与效果。大学图书馆成效评估的内容主要包括对学习、研究、教学的影响评估。该文结合国外大学图书馆成效评估的实践案例,对大学图书馆成效评估的定义、内容、意义以及评估指标体系等进行探索。成效评估是基于用户为中心的新的评估理论和方法,有利于争取社会各界对图书馆的支持和提高图书馆服务质量。     

End of the English (British?) Empire? Or Something Else?

The paper analyzes best-seller lists in seven major European book markets between April 2008 and March 2009. The paper’s authors introduce the concept of an impact factor for best-selling authors that shows how influential an author is in a given market and across the analyzed markets overall. The paper’s authors discovered that a new generation of European best-selling authors appeared in major book markets of Europe such that those not writing in English have an impact of almost twice that of the English writers. Furthermore, the authors have discovered that only veteran English or American best-selling authors tend to be published by big media conglomerates; the majority of the European best-selling authors were published by a surprising mix of big and small, independent and international publishing houses. It is striking that English as the most popular second language in the world did not play a stronger role as an intermediary language in the transmission of books from one European culture to another, as European publishers in major markets still employ editors who read a variety of languages and thus play the role of intermediaries in how books travel from one culture to another.     

地学核心期刊新媒体应用情况分析

【目的】通过分析中国地学核心期刊应用新媒体现状,为推动地学核心期刊新媒体化提供理论支持。【方法】统计对比分析《中国科技期刊引证报告》2012-2013年度地学核心期刊核心影响因子及核心被引频次及相关地学核心期刊网站新媒体应用数据。【结果】应用新媒体的地学核心期刊主要评价指标(核心被引频次和核心影响因子)总体都有较为显著的提升。【结论】新媒体的应用能够有效提升地学核心期刊的影响力和综合竞争力,地学期刊新媒体化将成为今后地学期刊发展的主流趋势。     

多硝基芳香化合物撞击感度的理论研究

采用密度泛函的方法，在3—21G基组水平上，对五种多硝基芳香化合物TNA(Ⅰ)、2，3．4，6-四硝基苯胺(Ⅱ)、五硝基苯胺(Ⅲ)、DATB(Ⅳ)、TATB(Ⅴ)炸药的撞击感度进行了理论研究，探讨苯环上引入氨基和硝基对该类炸药撞击敏感度的影响。结果表明，利用Mulliken键级可以很好的解释分子的撞击感度，氨基引入苯环后，炸药的撞击感度减小，硝基引入苯环后，撞击感度也发生了变化，其撞击敏感度顺序为：Ⅰ＞Ⅲ＞Ⅱ＞Ⅳ＞Ⅴ。     

从CSSCI透视我国管理学研究的地域和学科差距

利用CSSCI对管理学期刊的学术影响力、学术论文的分布及其省区间论文产出的差异程度做了简要分析，并提出几点建议。     

发表时滞与论文影响力关系研究——以图书情报学中文核心期刊为例

【目的】探析发表时滞与论文影响力的关系,寻找使论文影响力最大化的理想时滞区间,构建了发表时滞与论文影响力关系数学模型。【方法】采集2013年图书情报学中文核心期刊论文的发表时滞和被引频次数据,利用双参数威布尔分布的概率密度函数,分别对采集到的3785篇论文的发表时滞的概率分布、发表时滞与论文影响力的关系曲线进行拟合。【结果】2013年能使论文影响力最大化的理想发表时滞区间为31至210天,当年论文发表时滞的实际分布区间与理想状态尚存差距。【结论】进一步分析认为论文的影响力与其发表时滞的长短存在相关关系,存在能使论文影响力最大化的理想时滞区间,但发表时滞并非越短越好,预测国内期刊论文发表时滞有进一步缩短的趋势。