斑节对虾杆状病毒感染与水体理化因子   总被引：8，自引：0，他引：8  

李贵生  何建国  李桂峰  江静波  莫福  陆永涛  林宁  彭文国 《中山大学学报论丛》1996,(Z1)

通过二造虾塘水体理化因子的检测和斑节对虾杆状病毒感染的调查，发现水体理化因子可影响斑节对虾杆状病毒的感染度，其中影响最大的是氨氮，其次是盐度和亚硝酸氮．氨氟和pH值有协同作用，硫化物可诱发斑节对虾杆状病毒病，亚硝酸氮可明显地抑制对虾的生长．  相似文献   

关于教育投资直接经济效益计算问题的探讨--与申亚民等商榷   总被引：1，自引：0，他引：1  

邱雅 《教育与经济》2005,(4):9-11

本文认为《陕西省教育投资直接经济效益的实证分析》一文中教育投资贡献率的计算方法值得商榷．提出了对教育投资贡献率计算方法的改进意见。并根据实际数据进行我国教育投资对经济增长贡献率的实证分析。  相似文献   

陈垣先生对校勘学的贡献   总被引：1，自引：0，他引：1  

章继光 《五邑大学学报(社会科学版)》2001,3(3):40-42

陈垣《〈元典章〉校勘释例》综合前人经验与自己校读《元典章》的体会，将校书之法分为本校、对校、它校、理校四种。对古籍校勘第一次从理论上作出了系统的总结，使得自西汉末开始的校勘学在20世纪30年代成一门成熟的学科，厥功甚巨。  相似文献   

Exploring the forward citation patterns of patents based on the evolution of technology fields     

Su Jung Jee  Minji Kwon  Jung Moon Ha  So Young Sohn 《Journal of Informetrics》2019,13(4):100985

Forward citations of patents have been used extensively to capture the impact of technological knowledge. However, our understanding of the factors shaping patent citation patterns remains limited. One of the main limitations is the lack of scholarly attention paid to the dynamic influences arising from the evolution of technology fields. From an evolutionary perspective, technological impact is not simply determined by the static attributes of a technology itself; it is also dynamically affected by changes in the external conditions. Drawing on this viewpoint, this study suggests a model for understanding patent citation patterns by reflecting the evolution of the technology fields to which each patent belongs. Four such factors are explored: technology cycle time, potential of technological convergence, popularity of the technology field, and technological novelty. Based on the proposed model, we show how expected citation patterns can change as a result of different scenarios for technology field evolution. We conduct a case study of patents in the information technology and healthcare industries to show citation patterns of patents across heterogeneous industries as well as those within an industry. Contributions to the innovation literature and research investment decisions are discussed.  相似文献   

Can Google Scholar and Mendeley help to assess the scholarly impacts of dissertations?     

Kayvan Kousha  Mike Thelwall 《Journal of Informetrics》2019,13(2):467-484

Dissertations can be the single most important scholarly outputs of junior researchers. Whilst sets of journal articles are often evaluated with the help of citation counts from the Web of Science or Scopus, these do not index dissertations and so their impact is hard to assess. In response, this article introduces a new multistage method to extract Google Scholar citation counts for large collections of dissertations from repositories indexed by Google. The method was used to extract Google Scholar citation counts for 77,884 American doctoral dissertations from 2013 to 2017 via ProQuest, with a precision of over 95%. Some ProQuest dissertations that were dual indexed with other repositories could not be retrieved with ProQuest-specific searches but could be found with Google Scholar searches of the other repositories. The Google Scholar citation counts were then compared with Mendeley reader counts, a known source of scholarly-like impact data. A fifth of the dissertations had at least one citation recorded in Google Scholar and slightly fewer had at least one Mendeley reader. Based on numerical comparisons, the Mendeley reader counts seem to be more useful for impact assessment purposes for dissertations that are less than two years old, whilst Google Scholar citations are more useful for older dissertations, especially in social sciences, arts and humanities. Google Scholar citation counts may reflect a more scholarly type of impact than that of Mendeley reader counts because dissertations attract a substantial minority of their citations from other dissertations. In summary, the new method now makes it possible for research funders, institutions and others to systematically evaluate the impact of dissertations, although additional Google Scholar queries for other online repositories are needed to ensure comprehensive coverage.  相似文献   

How does collaboration affect researchers’ positions in co-authorship networks?     

Xiangjie Kong  Mengyi Mao  Huizhen Jiang  Shuo Yu  Liangtian Wan 《Journal of Informetrics》2019,13(3):887-900

Collaboration usually has a positive effect on researchers’ productivity: researchers have become increasingly collaborative, according to recent studies. Numerous studies have focused on enhancing research collaboration by recommendation technology and measuring the influence of researchers. However, few studies have investigated the effect of collaboration on the position of a researcher in the research social network. In this paper, we explore the relationships between collaboration and influence by social analytical methods, which are pertinent to analyzing the network structure and individual traits. We evaluate three aspects of the researchers’ influence: friendship paradox validation, social circle, and structure of a researcher's ego network. Furthermore, the ”six degrees of Bacon number” theory, generalized friendship paradox, and triadic closure theory are introduced to support our analysis. Experimental results show that collaboration can help researchers increase their influence to some extent.  相似文献   

Measuring scientific contributions with modified fractional counting     

Gunnar Sivertsen  Ronald Rousseau  Lin Zhang 《Journal of Informetrics》2019,13(2):679-694

We develop and propose a new counting method at the aggregate level for contributions to scientific publications called modified fractional counting (MFC). We show that, compared to traditional complete-normalized fractional counting, it eliminates the extreme differences in contributions over time that otherwise occur between scientists that mainly publish alone or in small groups and those that publish with large groups of co-authors. As an extra benefit we find that scientists in different areas of research turn out to have comparable average contributions to scientific articles. We test the method on scientists at Norway’s largest universities and find that, at an aggregate level, it indeed supports comparability across different co-authorship practices as well as between areas of research. MFC is thereby useful whenever the research output from institutions with different research profiles are compared, as e.g., in the Leiden Ranking. Finally, as MFC is actually a family of indicators, depending on a sensitivity parameter, it can be adapted to the circumstances.  相似文献   

Ranking scientific articles based on bibliometric networks with a weighting scheme     

Yu Zhang  Min Wang  Florian Gottwalt  Morteza Saberi  Elizabeth Chang 《Journal of Informetrics》2019,13(2):616-634

As the volume of scientific articles has grown rapidly over the last decades, evaluating their impact becomes critical for tracing valuable and significant research output. Many studies have proposed various ranking methods to estimate the prestige of academic papers using bibliometric methods. However, the weight of the links in bibliometric networks has been rarely considered for article ranking in existing literature. Such incomplete investigation in bibliometric methods could lead to biased ranking results. Therefore, a novel scientific article ranking algorithm, W-Rank, is introduced in this study proposing a weighting scheme. The scheme assigns weight to the links of citation network and authorship network by measuring citation relevance and author contribution. Combining the weighted bibliometric networks and a propagation algorithm, W-Rank is able to obtain article ranking results that are more reasonable than existing PageRank-based methods. Experiments are conducted on both arXiv hep-th and Microsoft Academic Graph datasets to verify the W-Rank and compare it with three renowned article ranking algorithms. Experimental results prove that the proposed weighting scheme assists the W-Rank in obtaining ranking results of higher accuracy and, in certain perspectives, outperforming the other algorithms.  相似文献   

Authorship analysis of specialized vs diversified research output     

Giovanni Abramo  Ciriaco Andrea D’Angelo  Flavia Di Costa 《Journal of Informetrics》2019,13(2):564-573

The present work investigates the relations between amplitude and type of collaboration (intramural, extramural domestic or international) and output of specialized versus diversified research. By specialized or diversified research, we mean within or beyond the author’s dominant research topic. The field of observation is the scientific production over five years from about 23,500 academics. The analyses are conducted at the aggregate and disciplinary level. The results lead to the conclusion that in general, the output of diversified research is no more frequently the fruit of collaboration than is specialized research. At the level of the particular collaboration types, international collaborations weakly underlie the specialized kind of research output; on the contrary, extramural domestic and intramural collaborations are weakly associated with diversified research. While the weakness of association remains, exceptions are observed at the level of the individual disciplines.  相似文献   

The evolving reference desk: A case study     

Christopher Ross Bowron  Joseph E. Weber 《The Journal of Academic Librarianship》2019,45(5):102057

  相似文献