American Physical Society Journals Research Articles

Loss of sustainability in scientific work

For decades the number of scientific publications has been rapidly increasing, effectively out-dating knowledge at a tremendous rate. Only few scientific milestones remain relevant and continuously attract citations. Here we quantify how long scientific work remains being utilized, how long it takes before today’s work is forgotten, and how milestone papers differ from those forgotten. To answer these questions, we study the complete temporal citation network of all American Physical Society journals. We quantify the probability of attracting citations for individual publications based on age and the number of citations they have received in the past. We capture both aspects, the forgetting and the tendency to cite already popular works, in a microscopic generative model for the dynamics of scientific citation networks. We find that the probability of citing a specific paper declines with age as a power law with an exponent of α ∼ −1.4. Whenever a paper in its early years can be characterized by a scaling exponent above a critical value, α c, the paper is likely to become ‘ever-lasting’. We validate the model with out-of-sample predictions, with an accuracy of up to 90% (area under the curve ∼ 0.9). The model also allows us to estimate an expected citation landscape of the future, predicting that 95% of papers cited in 2050 have yet to be published. The exponential growth of articles, combined with a power-law type of forgetting and papers receiving fewer and fewer citations on average, suggests a worrying tendency toward information overload and raises concerns about scientific publishing’s long-term sustainability.

Emergence and evolution of social networks through exploration of the Adjacent Possible space

The interactions among human beings represent the backbone of our societies. How people establish new connections and allocate their social interactions among them can reveal a lot of our social organisation. We leverage on a recent mathematical formalisation of the Adjacent Possible space to propose a microscopic model accounting for the growth and dynamics of social networks. At the individual’s level, our model correctly reproduces the rate at which people acquire new acquaintances as well as how they allocate their interactions among existing edges. On the macroscopic side, the model reproduces the key topological and dynamical features of social networks: the broad distribution of degree and activities, the average clustering coefficient and the community structure. The theory is born out in three diverse real-world social networks: the network of mentions between Twitter users, the network of co-authorship of the American Physical Society journals, and a mobile-phone-calls network.

Evolution of interdependent co-authorship and citation networks

Studies of bibliographic data suggest a strong correlation between the growth of citation networks and their corresponding co-authorship networks. We explore the interdependence between evolving citation and co-authorship networks focused on the publications, by Indian authors, in American Physical Society journals between 1970 and 2013. We record interactions between each possible pair of authors in two ways: first, by tracing the change in citations they exchanged and, second, by tracing the shortest path between authors in the co-authorship network. We create these data for every year of the period of our analysis. We use probability methods to quantify the correlation between citations and shortest paths, and the effect on the dynamics of the citation-co-authorship system. We find that author pairs who have a co-authorship distance $d \leq 3$ significantly affect each others citations, but that this effect falls off rapidly for longer distances in the co-authorship network. The exchange of citation between pairs with $d=1$ exhibits a sudden increase at the time of first co-authorship events and decays thereafter, indicating an aging effect in collaboration. This suggests that the dynamics of the co-authorship network appear to be driving those of the citation network rather than vice versa. Moreover, the majority of citations received by most authors are due to reciprocal citations from current, or past, co-authors. We conclude that, in order to answer questions on nature and dynamics of scientific collaboration, it is necessary to study both co-authorship and citation network simultaneously.

The strong nonlinear effect in academic dropout

Survivability is one of the features for success in contemporary science ecosystem. In this paper, we analyze the publication records of physicists in American Physical Society journals, aiming to identify the career length of each researcher and accordingly investigate the dropout phenomenon in science by the example of physicists. We find that scientific career is a complex nonlinear evolution process and can be generally divided into four stages regarding the dropout rate. In the early career, the dropout rate from trainee phase to maturity is high and negatively correlated with the research performance of the scientists, in both productivity and impact. Moreover, a strong nonlinearity is observed when we study the detailed relationship between the dropout rate and research performance. Interestingly, in the more mature stage of the career, the dropout rate becomes stable and independent of the early performance of the scientists. In the late career stage, the dropout rate increases and is mainly determined by retirement and external factors. The findings in this paper may provide useful guidance for young scholars to allocate their research effort in the early career.

Ranking scientific publications considering the aging characteristics of citations

Ranking the significance of scientific publications has been a challenging topic for a long time. So far, many ranking methods have been proposed, one of which is the well-known PageRank algorithm. In this paper, we introduce aging characteristics to the PageRank algorithm via considering only the first 10 year citations when aggregating resource from different nodes. The validation of our new method is performed on the data of American Physical Society journals. The results indicate that taking into account aging characteristics improves the performance of the PageRank algorithm in terms of ranking accuracy for both papers and authors. Though our method is only applied to citation networks in this paper, it can be naturally used in many other real systems and similar improvements are expected.

Structure and evolution of Indian physics co-authorship networks

We trace the evolution of Indian physics community from 1919 to 2013 by analyzing the co-authorship network constructed from papers published by authors in India in American Physical Society (APS) journals. We make inferences on India’s contribution to different branches of Physics and identify the most influential Indian physicists at different time periods. The relative contribution of India to global physics publication (research) and its variation across subfields of physics is assessed. We extract the changing collaboration pattern of authors between Indian physicists through various network measures. We study the evolution of Indian physics communities and trace the mean life and stationarity of communities by size in different APS journals. We map the transition of authors between communities of different sizes from 1970 to 2013, capturing their birth, growth, merger and collapse. We find that Indian–Foreign collaborations are increasing at a faster pace compared to the Indian–Indian. We observe that the degree distribution of Indian collaboration networks follows the power law, with distinct patterns between Physical Review A, B and E, and high energy physics journals Physical Review C and D, and Physical Review Letters. In almost every measure, we observe strong structural differences between low-energy and high-energy physics journals.

Interests diffusion on a semantic multiplex

Exploiting the information about members of a Social Network (SN) represents one of the most attractive and dwelling subjects for both academic and applied scientists. The community of Complexity Science and especially those researchers working on multiplex social systems are devoting increasing efforts to outline general laws, models, and theories, to the purpose of predicting emergent phenomena in SN’s (e.g. success of a product). On the other side the semantic web community aims at engineering a new generation of advanced services tailored to specific people needs. This implies defining constructs, models and methods for handling the semantic layer of SNs. We combined models and techniques from both the former fields to provide a hybrid approach to understand a basic (yet complex) phenomenon: the propagation of individual interests along the social networks. Since information may move along different social networks, one should take into account a multiplex structure. Therefore we introduced the notion of “Semantic Multiplex”. In this paper we analyse two different semantic social networks represented by authors publishing in the Computer Science and those in the American Physical Society Journals. The comparison allows to outline common and specific features.

Ranking scientific publications with similarity-preferential mechanism

Along with the advance of internet and fast updating of information, nowadays it is much easier to search and acquire scientific publications. To identify the high quality articles from the paper ocean, many ranking algorithms have been proposed. One of these methods is the famous PageRank algorithm which was originally designed to rank web pages in online systems. In this paper, we introduce a preferential mechanism to the PageRank algorithm when aggregating resource from different nodes to enhance the effect of similar nodes. The validation of the new method is performed on the data of American Physical Society journals. The results indicate that the similarity-preferential mechanism improves the performance of the PageRank algorithm in terms of ranking effectiveness, as well as robustness against malicious manipulations. Though our method is only applied to citation networks in this paper, it can be naturally used in many other real systems, such as designing search engines in the World Wide Web and revealing the leaderships in social networks.

Open Access and the Association Publisher, Summary of a Presentation by Dr. Martin Blume

The American Physical Society (APS) publishes eight titles along with Physical Review Focus (a free service that provides lay-person explanations of selected articles from the other APS journals) and two open access journals, Physical Review Special Topics: Accelerators and Beams (funded with institutional sponsorship) and Physical Review Special Topics: Physics Education Research (funded by author charges). ...

Speed of Publication — Stuck in First Gear

SPECIAL NEWS REPORT Publishers of electronic journals may debate how best to equip their offerings with search functions, interactive forums, supplementary material, and video displays [(see “Science Journals Go Wired”, this issue)][1]. But they have no doubt about the need for another feature: speed. Cutting the lag from submission to publication could be electronic journals' biggest selling point, say publishers. So far, however, they are falling short. “In the future, [electronic journals] have to be faster,” says Tim Ingoldsby, director of new product development at the American Institute of Physics. By eliminating the production, printing, and mailing steps, electronic publication can cut several weeks from the process—but that can still leave a lag of months between a paper's submission and its appearance. Journal publishers are striving to shrink that gap, and reader and author expectations aren't the only spur. There's also the prospect of competition from electronic preprint archives—low-budget, non-peer-reviewed operations like the Los Alamos e-print archives, which every week publishes several hundred new preprints, all of them within minutes, if not seconds, of submission. One stopgap for traditional publishers is to put articles on-line as soon as they've been accepted, rather than bundling them with others as an entire issue. In the case of one electronic journal, [ Astrophysical Journal Letters ][2], this helps cut submission-to-publication time from 20 weeks to 17. But efforts to save even more time run up against a human factor. Most of the publication lag is due, says Ingoldsby, to “the peer-review step and the waiting for the author to return corrected galleys step.” Or, as Elsevier Associate Publisher Nigel Fletcher-Jones says, “It's getting people to sit down, read the manuscript, and do something with it.” “We have to rethink how this whole process works,” says Bob Kelly, director of journal information systems at the American Physical Society (APS). “And the first step would be put the whole thing on line”—from electronic submission of manuscripts, through refereeing, revising, and editing, to electronic publication of the finished copy. To encourage authors to submit papers electronically, the APS is thinking of setting up publicly accessible preprint archives complementary to those run by Los Alamos, covering the physics disciplines not accommodated by the Los Alamos archives. That way, physicists will be able to submit papers to [ Physical Review Letters ][3] and other APS journals from either set of archives. With no need to rely on the mails for receiving manuscripts or sending out reviewers' copies, says Kelly, the manuscript handling process would accelerate “to the blink of an eye.” The APS is also considering shipping out interactive software to its referees. Not only would on-screen refereeing speed up the mechanical steps of receiving, marking up, and returning a manuscript, but it might also have a psychological effect, says Kelly. “Some recent studies have shown that some referees are responding quicker because they're receiving a manuscript electronically: It's there, they look at it, and get rid of it as opposed to having it disappear into a pile of paper on their desk.” With the submission-to-publication system completely “re-engineered,” he says, the APS may be able to cut the minimum publication time of an article from 3 months to one. Whether that will be fast enough for impatient Internet users remains to be seen, of course. If it isn't, says Ingoldsby, at least in physics, “these preprint servers like the Los Alamos operation are going to drive traditional publishers out of business.” [1]: /lookup/doi/10.1126/science.271.5250.764 [2]: http://www.sciencemag.org/cgi/content/full/271/5250/URL_ROOT/scripts/redirect-note?http://www.aas.org/ApJ/ [3]: http://www.sciencemag.org/cgi/content/full/271/5250/URL_ROOT/scripts/redirect-note?http://aps.org/Journals/PRL-online/