Guan Yingjun, Du Jing, Torvik Vetle I
School of Information Sciences, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA.
WOSP 2017 (2017). 2017 Dec;2017:40-45. doi: 10.1145/3127526.3127534.
We analyze nearly 20 million geocoded PubMed articles with author affiliations. Using K-means clustering for the lower 48 US states and mainland China, we find that the average published paper is within a relatively short distance of a few centroids. These centroids have shifted very little over the past 30 years, and the distribution of distances to these centroids has not changed much either. The overall country centroids have gradually shifted south (about 0.2° for the USA and 1.7° for China), while the longitude has not moved significantly. These findings indicate that there are few large scientific hubs in the USA and China and the typical investigator is within geographical reach of one such hub. This sets the stage to study centralization of biomedical research at national and regional levels across the globe, and over time.
我们分析了近2000万篇带有作者单位地理编码的PubMed文章。对美国本土48个州和中国大陆使用K均值聚类法，我们发现平均发表的论文距离少数几个质心相对较近。在过去30年里，这些质心几乎没有移动，到这些质心的距离分布也没有太大变化。总体而言，国家质心逐渐向南移动（美国约0.2°，中国约1.7°），而经度没有明显移动。这些发现表明，美国和中国很少有大型科学中心，典型的研究人员在一个这样的中心的地理范围内。这为研究全球范围内以及随着时间推移生物医学研究在国家和地区层面的集中化奠定了基础。
