Proximity among scientists in social, cognitive, and physical dimensions promotes the sharing of tacit knowledge. Tacit knowledge helps scientists to understand the credibility of papers they read and to use the results in subsequent research. Hence, given the proximity among scientists in social, cognitive, and physical dimensions, one can predict patterns of diffusion in science. However, for controversial knowledge claims to become replicated, one expects the proximity between scientists itself to change as like-minded scientists relocate and create new coalitions. Proximity can thus be used as a unifying concept for the study of scientific knowledge diffusion as well as for the analysis of mobility of scientists.

Scientific breakthroughs are commonly understood as discoveries that transform the knowledge frontier and have a major impact on science, technology, and society. Prior literature studying breakthroughs generally treats them as a homogeneous group in attempts to identify supportive conditions for their occurrence. In this paper, we argue that there are different types of scientific breakthroughs, which differ in their disciplinary occurrence and are associated with different considerations of use and citation impact patterns. We develop a typology of scientific breakthroughs based on three binary dimensions of scientific discoveries and use this typology to analyze qualitatively the content of 335 scientific articles that report on breakthroughs. For each dimension, we test associations with scientific disciplines, reported use considerations, and scientific impact. We find that most scientific breakthroughs are driven by a question and in line with literature, and that paradigm shifting discoveries are rare. Regarding the scientific impact of breakthrough as measured by citations, we find that an article that answers an unanswered question receives more citations compared to articles that were not motivated by an unanswered question. We conclude that earlier research in which breakthroughs were operationalized as highly cited scientific articles may thus be biased against the latter.

Open access (OA) publishing has created new academic and economic niches in contemporary science. OA journals offer numerous publication outlets with varying editorial philosophies and business models. This article analyzes the Directory of Open Access Journals (DOAJ) ( n = 12,127) to identify characteristics of OA academic journals related to the adoption of article processing charge (APC)-based business models, as well as the price points of journals that charge APCs. Journal impact factor (JIF), language, publisher mission, DOAJ Seal, economic and geographic regions of publishers, peer review duration, and journal discipline are all significantly related to the adoption and pricing of journal APCs. Even after accounting for other journal characteristics (prestige, discipline, publisher country), journals published by for-profit publishers charge the highest APCs. Journals with status endowments (JIF, DOAJ Seal) and articles written in English, published in wealthier regions, and in medical or science-based disciplines are also relatively costlier. The OA publishing market reveals insights into forces that create economic and academic value in contemporary science. Political and institutional inequalities manifest in the varying niches occupied by different OA journals and publishers.