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231.
Mike Thelwall 《Journal of Informetrics》2018,12(2):430-435
Dimensions is a partly free scholarly database launched by Digital Science in January 2018. Dimensions includes journal articles and citation counts, making it a potential new source of impact data. This article explores the value of Dimensions from an impact assessment perspective with an examination of Food Science research 2008–2018 and a random sample of 10,000 Scopus articles from 2012. The results include high correlations between citation counts from Scopus and Dimensions (0.96 by narrow field in 2012) as well as similar average counts. Almost all Scopus articles with DOIs were found in Dimensions (97% in 2012). Thus, the scholarly database component of Dimensions seems to be a plausible alternative to Scopus and the Web of Science for general citation analyses and for citation data in support of some types of research evaluations. 相似文献
232.
Facebook is challenging professional journalism. These challenges were evident in three incidents from 2016: the allegation that Facebook privileged progressive-leaning news on its trending feature; Facebook’s removal of the Pulitzer Prize-winning “Napalm Girl” photo from the pages of prominent users; and the proliferation of “fake news” during the US presidential election. Using theoretical concepts from the field of boundary work, this paper examines how The Guardian, The New York Times, Columbia Journalism Review and Poynter editorialized Facebook’s role in these three incidents to discursively construct the boundary between the value of professional journalism to democracy and Facebook’s ascendant role in facilitating essential democratic functions. Findings reveal that these publications attempted to define Facebook as a news organization (i.e., include it within the boundaries of journalism) so that they could then criticize the company for not following duties traditionally incumbent upon news organizations (i.e., place it outside the boundaries of journalism). This paper advances scholarship that focuses on both inward and outward conceptions of boundary work, further explores the complex challenge of defining who a journalist is in the face of rapidly changing technological norms, and advances scholarship in the field of media ethics that positions ethical analysis at the institutional level. 相似文献
233.
查代春 《江西广播电视大学学报》2006,31(4):88-90
广告效果下降是当前广告业的一种普遍现象,成为困扰广告商和广告公司的一个难题。如何创制更有新意、更有效果的广告,使广告传递的商品信息让受众注意、形成记忆、产生行动是广告人努力的方向。本文通过时广告效果下降原因的剖析,提出了相应的对策和措施。 相似文献
234.
关于学习控制的定量分析 总被引:3,自引:0,他引:3
本文根据著名教育技术学家瑞奇鲁斯 (C .M .Reigeluth)的影响学习控制的主要因素 ,将其进行量化处理 ,并设计出相应的计算公式 ,然后根据学习控制定量分析调查结果 ,计算学习控制的量化数据 ,利用定量分析的方法 ,指导教师制定和实施相应的教学策略。 相似文献
235.
BackgroundPlanctomycetes is a phylum of biofilm-forming bacteria with numerous biosynthetic gene clusters, offering a promising source of new bioactive secondary metabolites. However, the current generation of chemically defined media achieves only low biomass yields, hindering research on these species. We therefore developed a chemically defined medium for the model organism Planctopirus limnophila to increase biomass production.ResultsWe found that P. limnophila grows best with a 10 mM sodium phosphate buffer. The replacement of complex nitrogen sources with defined amino acid solutions did not inhibit growth. Screening for vitamin requirements revealed that only cyanocobalamin (B12) is needed for growth. We used response surface methodology to optimize the medium, resulting in concentrations of 10 g/L glucose, 34 mL/L Hutner’s basal salts, 23.18 mM KNO3, 2.318 mM NH4Cl and 0.02 mg/L cyanocobalamin. The analysis of amino acid consumption allowed us to develop a customized amino acid solution lacking six of the amino acids present in Aminoplasmal 10%. Fed-batch cultivation in a bioreactor using the optimized medium achieved a final ΔOD600 of 46.8 ± 0.5 after 108 h, corresponding to a cell dry weight of 13.6 ± 0.7 g/L.ConclusionsThe optimized chemically defined medium allowed us to produce larger amounts of biomass more quickly than reported in earlier studies. Further research should focus on triggering P. limnophila biofilm formation to activate the gene clusters responsible for secondary metabolism.How to cite: Kruppa OC, Gerlach D, Fan R, et al. Development of a chemically defined medium for Planctopirus limnophila to increase biomass production. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.09.002. 相似文献
236.
ABSTRACT This study used the 2017 Las Vegas and 2016 Orlando mass shootings as case studies to explore alleged double standards in reporting of events featuring Muslim and non-Muslim mass perpetrators of violence. The study used framing theory and content analysis to examine Los Angeles Times and New York Times coverage of the shootings during the one week immediately following each event. Findings are consistent with previous literature and the researchers’ expectations. The Orlando shooting, carried out by a Muslim, was allotted more coverage despite the fact that it produced nine fewer fatalities than the Las Vegas shooting, perpetrated by a white non-Muslim. The analysis also showed that the examined newspapers were more likely to employ a “terrorism” frame in their coverage of the Orlando shooting than in their coverage of the Las Vegas shooting; link the Orlando mass shooting with the global war on terrorism; and to humanize Stephen Paddock, the white perpetrator of the Las Vegas shooting. Framing differences found in this study may contribute to downplaying the threat of white male gun violence, and to reinforcing fears of Islam and Muslims. 相似文献
237.
We investigate the strategies used by 64 advanced secondary mathematics students to identify whether a given pair of polynomial representations (graphs, tables, or equations) corresponded to the same function on an assessment of coordinating representations. Participants also completed assessments of domain-related knowledge and background skills. Cluster analysis of strategies by representation pair revealed patterns in the participants' strategy use. Two clusters were identifiable on tasks that required matching equations to graphs and graphs to tables. We identified overlap between these two clusters, suggesting that while the representation pair influenced strategy choice, there was also a general distinction between students who used more and less sophisticated strategies. However, students who used more sophisticated coordination strategies were similar to the others on measures of domain-specific knowledge or background skills. We consider implications for future investigations testing interventions to promote coordinating representations. 相似文献
238.
在高校体育选修课程中,瑜伽通过调吸调身调心,达到身心灵合一的境界,受到众多女大学生的欢迎和喜爱,而在教学过程中,学生普遍存在一些有关呼吸方面的困惑。针对这一问题的现状进行简单分析,提出解决方案,希望对以后的教学工作有一定的指导意义。 相似文献
239.
许建国 《晋城职业技术学院学报》2011,4(5):23-25
城乡结合部中小学生面临的心理困境有日趋增多的趋势。困境产生的原因主要来自社会、学校、家庭和学生个人四个方面。只有采取强化心理健康教育工作、提高教师心理健康教育能力、构建心理健康教育体系等对策,才能使中小学生走出心理困境,实现全面发展。 相似文献
240.
An effect size of about .70 (or .40–.70) is often claimed for the efficacy of formative assessment, but is not supported by the existing research base. More than 300 studies that appeared to address the efficacy of formative assessment in grades K‐12 were reviewed. Many of the studies had severely flawed research designs yielding uninterpretable results. Only 13 of the studies provided sufficient information to calculate relevant effect sizes. A total of 42 independent effect sizes were available. The median observed effect size was .25. Using a random effects model, a weighted mean effect size of .20 was calculated. Moderator analyses suggested that formative assessment might be more effective in English language arts (ELA) than in mathematics or science, with estimated effect sizes of .32, .17, and .09, respectively. Two types of implementation of formative assessment, one based on professional development and the other on the use of computer‐based formative systems, appeared to be more effective than other approaches, yielding mean effect size of .30 and .28, respectively. Given the wide use and potential efficacy of good formative assessment practices, the paucity of the current research base is problematic. A call for more high‐quality studies is issued. 相似文献