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71.
欧美出版社开放存取期刊论文处理费研究 总被引:1,自引:0,他引:1
论文处理费伴随着开放存取期刊的出现而进入公众视野。20世纪末,开放存取期刊由于没有成熟的商业盈利模式,国际上知名的出版社均对这种新型数字出版方式表示过疑虑。而现今,传统出版集团相继发行各自的开放存取平台,这主要得益于论文处理费的推行。本文介绍欧美各大知名出版社旗下开放存取期刊论文处理费的相关收费情况,分析论文处理费收取的完整体系,以期为国内学术期刊开放存取平台的发展提供策略建议。 相似文献
72.
通过对感觉统合与感觉统合失调的概念与机制、发生原因与危害,以及感觉统合训练概念与理论依据、效应等进行分析与研究。指出人对外界的正确应答能力是不同感觉刺激在大脑中经无数次统合训练而习得的;儿童的感觉统合失调既有神经解剖学原因,也与刺激量与类别的缺失有关;其危害主要表现在学习障碍、心理障碍、社会适应障碍以及社会行为与生活能力障碍等方面;而感觉统合训练是防治儿童感觉统合失调的一种有效方法。在此基础上,提出了针对学童感觉统合失调问题的小学体育教学建议。 相似文献
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滇西边境地区的保山、德宏自明清以来就是我国传统的宝玉石集散地和加工中心,由于诸多的原因一度衰落或者发展的不理想;在桥头堡发展战略的背景下,滇西边境地区成为我国西南对外开放的前沿,具有发展珠宝业特殊的地缘优势和资源优势,将滇西边境地区重新建设成为宝玉石交易的集散地和加工中心,从现实情况分析是可行的. 相似文献
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Large-scale web search engines are composed of multiple data centers that are geographically distant to each other. Typically, a user query is processed in a data center that is geographically close to the origin of the query, over a replica of the entire web index. Compared to a centralized, single-center search engine, this architecture offers lower query response times as the network latencies between the users and data centers are reduced. However, it does not scale well with increasing index sizes and query traffic volumes because queries are evaluated on the entire web index, which has to be replicated and maintained in all data centers. As a remedy to this scalability problem, we propose a document replication framework in which documents are selectively replicated on data centers based on regional user interests. Within this framework, we propose three different document replication strategies, each optimizing a different objective: reducing the potential search quality loss, the average query response time, or the total query workload of the search system. For all three strategies, we consider two alternative types of capacity constraints on index sizes of data centers. Moreover, we investigate the performance impact of query forwarding and result caching. We evaluate our strategies via detailed simulations, using a large query log and a document collection obtained from the Yahoo! web search engine. 相似文献
75.
设计、合成了一种基于罗丹明B的铜离子荧光分子探针RF。研究发现在V乙腈∶V水=1∶1介质中,化合物RF最大发射波长为566 nm,Cu2+可使探针RF的荧光强度明显增大,同时溶液颜色从无色变为桃红色。该荧光探针对Cu2+具有较高的灵敏度和较好的选择性。RF的选择性荧光增强是由于其对Cu2+的识别开环引起的。该探针对Cu2+的识别是不可逆的,而且pH对探针RF在中性水溶液中检测Cu2+几乎没有影响。 相似文献
76.
This study analyzes gains in cognitive components of learning competence with respect to cohorts based on ability tracking in a Czech longitudinal study. Propensity score matching is used to form parallelized samples of academic and non-academic track students and to eliminate the effect of selective school intake. We applied regression models on the total scores to test for the overall track effect. Furthermore, we analyze scores and gains on the subscores and check for differential item functioning in Grade 6 and in change to Grade 9. While after 3 years, no significant difference between the two tracks was apparent in the total learning competence score, we did, however, find significant differences in some subscores and in the functioning of some items. We argue that item-level analysis is important for deeper understanding of the tracking implications and may provide the basis for more precise evidence-based decisions regarding the tracking policy. 相似文献
77.
通过分析单臂电桥的绝对灵敏度 ( Sa)与相对灵敏度 ( Sr)和关系 ,运用 Δ-Y变换 ,得出了双臂电桥的 Sa 与 Sr 之间的关系 ,探讨了双臂电桥的比例臂的不同选择对电桥灵敏度的影响 相似文献
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This research aims to promote our understanding of feedback engagement processes in writing tasks using a combination of online and offline measures, including eye-tracking, thinking-aloud, and text-analyses. Study 1 explored how sixteen students read, evaluate, and use feedback for revision. Results revealed three feedback processing strategies: (1) superficial processing (n = 6), which is characterized by reading feedback in a linear way, without critically rereading or revising the text, (2) local processing (n = 6) in which students switched between reading the comments and the commented text, and (3) deep processing (n = 4) in which students integrated the feedback with both commented and uncommented parts of the text and made more substantial revisions. In Study 2, we investigated the local and deep feedback reading strategy in more detail with 41 students using a within-subject design with different types of feedback. Results demonstrated the same strategies among students, but also that the focus of feedback affected students' revision behavior, above and beyond an individual feedback processing strategy. This finding is in line with previous research that emphasized the effects of feedback characteristics on students’ use of feedback. By triangulating various process measures, this research is one of the first that provides empirical evidence for different feedback processing strategies among students. These novel insights in individual feedback engagement processing can be used to extend and refine current theories on how, when, and why feedback works and for whom. 相似文献