The geography of references in elite articles: What countries contribute to the archives of knowledge

This study is intended to find an answer for the question on which national "shoulders" the worldwide top-level research stands. Traditionally, national scientific standings are evaluated in terms of the number of citations to their papers. We raise a different question: instead of analyzing the citations to the countries' articles (the forward view), we examine referenced publications from specific countries cited in the most elite publications (the backward-citing-view). "Elite publications" are operationalized as the top-1% most-highly cited articles. Using the articles published during the years 2004 to 2013, we examine the research referenced in these works. Our results confirm the well-known fact that China has emerged to become a major player in science. However, China still belongs to the low contributors when countries are ranked as contributors to the cited references in top-1% articles. Using this perspective, the results do not point to a decreasing trend for the USA; in fact, the USA exceeds expectations (compared to its publication share) in terms of contributions to cited references in the top-1% articles. Switzerland, Sweden, and the Netherlands also are shown at the top of the list. However, the results for Germany are lower than statistically expected

Betweenness and Diversity in Journal Citation Networks as Measures of Interdisciplinarity -- A Tribute to Eugene Garfield --

Journals were central to Eugene Garfield's research interests. Among other things, journals are considered as units of analysis for bibliographic databases such as the Web of Science (WoS) and Scopus. In addition to disciplinary classifications of journals, journal citation patterns span networks across boundaries to variable extents. Using betweenness centrality (BC) and diversity, we elaborate on the question of how to distinguish and rank journals in terms of interdisciplinarity. Interdisciplinarity, however, is difficult to operationalize in the absence of an operational definition of disciplines, the diversity of a unit of analysis is sample-dependent. BC can be considered as a measure of multi-disciplinarity. Diversity of co-citation in a citing document has been considered as an indicator of knowledge integration, but an author can also generate trans-disciplinary--that is, non-disciplined--variation by citing sources from other disciplines. Diversity in the bibliographic coupling among citing documents can analogously be considered as diffusion of knowledge across disciplines. Because the citation networks in the cited direction reflect both structure and variation, diversity in this direction is perhaps the best available measure of interdisciplinarity at the journal level. Furthermore, diversity is based on a summation and can therefore be decomposed, differences among (sub)sets can be tested for statistical significance. In an appendix, a general-purpose routine for measuring diversity in networks is provided

Recent Developments in China-U.S. Cooperation in Science

China's remarkable gains in science over the past 25 years have been well documented (e.g., Jin and Rousseau, 2005a; Zhou and Leydesdorff, 2006; Shelton & Foland, 2009) but it is less well known that China and the United States have become each other's top collaborating country. Science and technology has been a primary vehicle for growing the bilateral relationship between China and the United States since the opening of relations between the two countries in the late 1970s. During the 2000s, the scientific relationship between China and the United States--as measured in coauthored papers--showed significant growth. Chinese scientists claim first authorship much more frequently than U.S. counterparts by the end of the decade. The sustained rate of increase of collaboration with one other country is unprecedented on the U.S. side. Even growth in relations with eastern European nations does not match the growth in the relationship between China and the United States. Both countries can benefit from the relationship, but for the U.S., greater benefit would come from a more targeted strategy.Comment: Conference on China's Science and Technology International Relations, April, 2014, Arizona State University; accepted for publication in Minerva, April 201

Generating clustered journal maps: an automated system for hierarchical classification

Journal maps and classifications for 11,359 journals listed in the combined Journal Citation Reports 2015 of the Science and Social Sciences Citation Indexes are provided at https://leydesdorff.github.io/journals/ and http://www.leydesdorff.net/jcr15. A routine using VOSviewer for integrating the journal mapping and their hierarchical clusterings is also made available. In this short communication, we provide background on the journal mapping/clustering and an explanation about and instructions for the routine. We compare journal maps for 2015 with those for 2014 and show the delineations among fields and subfields to be sensitive to fluctuations. Labels for fields and sub-fields are not provided by the routine, but an analyst can add them for pragmatic or intellectual reasons. The routine provides a means of testing one’s assumptions against a baseline without claiming authority; clusters of related journals can be visualized to understand communities. The routine is generic and can be used for any 1-mode network