光的反射定律探究实验改进

苏科版初二物理光学探究光的反射定律,做了这样一个实验:将一束手电筒或激光笔的光照射到平面镜上,用光屏接受到光斑,改变入射光束照射到平面镜的角度,观察光斑位置的变化.     

马拉松消费者行为研究:特征、挑战与趋势

采用实地问卷调查法,收集马拉松参赛者在运动参与行为、实物购买行为和人口特征方面的统计数据,使用k-means聚类分析将马拉松消费者细分为资深马拉松追求者、普通马拉松爱好者和社交者三个集群。研究表明,马拉松消费将面临以下挑战:泛娱乐性大于竞技性造成资深消费群体流失,赛事体系层级不清晰造成消费者混淆,赛事运营服务不专业拉低消费意愿,其他户外运动兴起导致消费份额分化,马拉松消费者非理性消费观念广泛存在。预测未来马拉松消费行为发展的六大趋势:以重点人群为目标扩大马拉松消费;科学跑马服务助力消费者持续参与赛事;沉浸体验式消费不断升级;建设马拉松产业载体拓展消费空间;社交媒体互动式消费发挥中介作用;5G开启智能马拉松消费时代。     

中国大企业自主创新能力的实证测度与分析研究

 大企业是国家自主创新的重要生力军,是国家经济实力的基础和依托。本文基于灰色白化权函数定权聚类法构建了大企业自主创新能力的评价模型,并运用AHP法对测度指标进行了赋权,以33个制造业大企业为样本,对其自主创新能力进行了实证测度。结果显示：当前我国大企业自主创新能力总体状况很不乐观,其主要测度指标的表现也很不理想,与世界知名创新型企业尚有较大差距,挑战严峻,形势紧迫。     

幸福与自由——亚当·斯密心中的理想商业社会

亚当·斯密从研究人性入手,认为人类本性之目标有六个:自保、种的繁衍、秩序、幸福、种的完善以及自由.以此为理论预设,斯密对未来理想商业社会进行了勾勒,借此批判他所处的西欧社会之弊端,并提出相应的改革方案.斯密理想商业社会旨在实现人的幸福和自由.在这里,幸福与自由被赋予特定的内涵,这一内涵标志着斯密摆脱了后人给他贴上的标签:追求一种简单的布尔乔亚式的理想社会.     

The neutrophil-lymphocyte ratio to predict poor prognosis of critical acute myocardial infarction patients: a retrospective cohort study

IntroductionInflammation is closely related to adverse outcomes of acute myocardial infarction (AMI). This study aimed to evaluate whether neutrophil-lymphocyte ratio (NLR) can predict poor prognosis of critical AMI patients.Materials and methodsWe designed a retrospective cohort study and extracted AMI patients from the “Medical Information Mart for Intensive Care-III” database. The primary outcome was 1-year all-cause mortality. The secondary outcomes were 90-day and in-hospital all-cause mortalities, and acute kidney injury (AKI) incidence. The optimal cut-offs of NLR were picked by X-tile software according to the 1-year mortality and patient groups were created: low-NLR (< 4.8), high-NLR (4.8 - 21.1), and very high-NLR (> 21.1). Cox and modified Poisson regression models were used to evaluate the effect of NLR on outcomes in critically AMI patients.ResultsFinally, 782 critical AMI patients were enrolled in this study, and the 1-year mortality was 32% (249/782). The high- and very high-NLR groups had a higher incidence of outcomes than the low-NLR group (P < 0.05). The multivariate regression analyses found that the high- and very high-NLR groups had a higher risk of 1-year mortality (Hazard ratio (HR) = 1.59, 95% CI: 1.12 to 2.24, P = 0.009 and HR = 1.73, 95% CI: 1.09 to 2.73, P = 0.020), 90-day mortality (HR = 1.69, 95% CI: 1.13 to 2.54, P = 0.011 and HR = 1.90, 95% CI: 1.13 to 3.20, P = 0.016), in-hospital mortality (Relative risk (RR) = 1.77, 95% CI: 1.14 to 2.74, P = 0.010 and RR = 2.10, 95% CI: 1.23 to 3.58, P = 0.007), and AKI incidence (RR = 1.44, 95% CI: 1.06 to 1.95, P = 0.018 and RR = 1.34, 95% CI: 0.87 to 2.07, P = 0.180) compared with low-NLR group. NLR retained stable predictive ability in sensitivity analyses.ConclusionBaseline NLR is an independent risk factor for 1-year mortality, 90-day mortality, in-hospital mortality, and AKI incidence in AMI patients.     

基于网络论坛的数字参考咨询工作实践

网络的发展和普及改变了参考咨询服务的环境。文章介绍了南京医科大学在利用自建的医林风信论坛进行参考咨询服务的情况。     

略谈对图书馆员的人性化管理

文章从人本思想出发,在对图书馆员的现状进行剖析的基础上,对图书馆员的人性化管理提出了自己的看法。     

"铜片镀锌"最佳实验条件的分析和研究

电镀属于电化学部分电解的内容,通过电镀实验不但可以使学生更好地理解电解原理,而且对于激发学生学习化学的兴趣有一定的积极作用.     

巧用"缺氢指数"解有机化学问题

1 "缺氢指数"的概念 有机物的"缺氢指数"(符号为Ω表示)是以饱和链烃(CnH2n 2)为基准,当n个碳原子结合2n 2个氢原子即达到"饱和",则此有机物的"缺氢指数"等于零.其它有机物与饱和链烃相比较每少2个氢原子其"缺氢指数"增加1,以此类推.对于烃(CxHy)(相应的饱和链烃CxH2x 2)的"缺氢指数"计算公式: