Scientometric Assessment of Indian Scientists’ Contribution to Selected Physical Review Journals

The present study reveals Indian authorship trend and their contribution in five selected highly cited journals of American Physical Society (APS) as reflected in the Web of Science (WoS) database. During 2004-2018, India placed 11th rank having 4.6% contribution and Indian scientists published total 9,823 research articles including 50.98% international collaboration. The Physical Review D (PRD) journal published majority of Indian authored articles which also get larger citations impact and developed European countries like USA, Germany and France were the leading collaborating countries. Maximum articles received citations in the range of ≥1 <10 and only 194 articles attracted at least 100 or more citations. It is also found that the Indian scientists involved in high energy physics produced significant research articles under international collaborative experimental groups like ALICE, ATLAS, STAR etc to share cost, infrastructure and capabilities. The study will be helpful for policy makers and scientists in identifying Indian researchers’ publication pattern in the selected APS journals of repute.


INTRODUCTION
Since Independence, India's Higher Education system has witnessed a paradigm shift and has became the third largest higher education system in the world, after the US and China. [1] India's large science and technology (S&T) infrastructure comprises 920 UGC affiliated Universities and 95 Institution of National Importance, many R&D laboratories, centers, Govt. departments as well as private institutions. [2] Due to the significant growth of S&T infrastructure and S&T investments in the country, a huge number of research findings are coming out and publishing in different national as well as international journals of repute. However, the Indian scientists prefer to publish their scientific results in foreign journals rather than national level journals due to absence of sufficient good quality journals and also for wider recognition and credibility. [3,4] Founded in 1899, the American Physical Society (APS) is a professional body that serves the international physics community with internationally known and highly cited peer-reviewed research journals. [5] Therefore, the present study is an effort to identify the Indian authorship contribution and trend in the selected APS journals by seeking answer to the following research questions.
i. What are the Indian scientists' contributions to reputed APS journals?
ii. What patterns of collaboration trend are evidenced among the scientists and their scholarly impacts?
iii. What are the primary collaborating countries and participated institutions? iv. What are the emphasized and focus research areas among the scientists?

Literature Review
The literature review summarizes and highlights the related papers on present research scenario of S&T in India as well as in the discipline of physics or sub-branch areas.
Hiremath, Gourikeremath, Hadagali and Kumbar [6] assessed India's publication growth in S&T during 1989-2014 and reported that India's publication trend corresponds to the world's average. The Bhabha Atomic Research Centre (BARC), Mumbai played dominant role followed by the Indian Institute of Science (IISc), Bengaluru. Garg, Dutt and Kumar [7] evaluated the papers of Indian scientists for the year 1997 as covered in the Science Citation Index (SCI) and reported that physical sciences, chemical sciences and medical sciences produced about 57% of the total output. In another study, Basu and Aggarwal [8] evaluated the impact of international collaboration on institutional performance in India and showed that the Tata Institute of Fundamental Research (TIFR), Mumbai had a very high productivity, collaboration and IF.Gupta and Dhawan [9] stated that India ranks 12th place in science and technology (S&T) research having 2.04% global publications share during 1996-2006. Further, Physical sciences subject dominates the S&T research domain in India. In another study, Gupta and Dhawan [10] pointed out that condensed matter physics is the most popular sub-field in Physics research in India and found that Physical Review B has been considered as the most productive journal. Dhawan [11] also investigated the trend of physics research in India and China during 1990 and 1995 and reported that China is ahead of India and ranked 7 th in the world while India placed 10 th position.
Raina, Gupta and Kandhari [12] made an attempt to identity the evolutionary trend of collaboration in India in four subdisciplines of physics during 1800-1950 and also discovered the collaboration profiles of four renowned physicists. In the history of Indian physics, the decade of 1920-30 constitutes the main landmark period and witnessed a quantum leap in publications. In another paper, Raina and Gupta [13] assessed the process of the institutionalization of research in physics in India during 1900-1950 in terms of author productivity, subdiscipline wise productivity, collaboration, globalization and country wise distribution of publications.
Bhattacharya, Singh and Sudhakar [14] in their macro level analytical study, evaluated the changes in research priorities in major fields of Physics of thirty three countries during two different time periods -1990 and 1995. The study showed that South Korea has shown a remarkable increase in rank while India lost its position from 8 th to 10 th place. Khanna, Singh, Tewari and Saini [15] analyzed the publications output of the Guru Nanak Dev University (GNDU), Amritsar in physics and astronomy during the period 2006-15 and pointed out that among leading 25 Indian Universities, the University of Delhi shared majority of the publications followed by Panjab University whereas GNDU ranked 23 rd position with 652 publications.
Sudhier [16] examined 352 scholarly publications appended in the Physics doctoral thesis of researchers of Indian Institute of Science (IISc) and the University of Kerala (KU) during 2004-2008 on several aspects like publication productivity, authorship trend, ranked journals, communication channels etc and pointed out that the Physicists prefer to publish research findings in American Physical Society (APS) journals. Rajan, Swaminathan and Vaidhyasubramaniam [17] pointed out that the research productivity from Indian institutions has been steadily increasing in last few years and materials science, physics and astronomy were the strong subject areas with maximum quality output.
It is evident from the above review that Indian scientists contribute a significant proportion of publications share at the Global level and physical science is the top priority area of research in India. In this context, the present endeavor explores the Indian physicists' contribution to global level reputed journals of American Physical Society.

Objectives of the Study
The present study examines the Indian researchers' contribution in five selected American Physical Society (APS) journals during 2004 -2018 using scientometric methods. It especially looks at the key trends based on authorship pattern, collaboration activity, partnering countries, participated institutions and citation impact.

Data source, limitations and methodology
The present scientometric study covers only Indian authored/ co-authored articles published in the Physical Review journals for last 15 years spanning from the period of 2004 to 2018. The Physical Review journals [5] are published by the American Physical Society (APS) and it has the collection of 15 leading international peer-reviewed research journals. But, the present study considers only five oldest research journals (Table  1) of APS. However, the Reviews of Modern Physics (1929-) publishes review based articles and Physical Review Letters (1958-) publishes shorter articles of broader interest. Hence, these two oldest journals have been excluded from the study.
The 'Physical Review' journals first published in 1893 and later in 1970, the journal splits into several sub-journals titled Physical Review A, B, C and D to focus particular field of physics. Later on, in 1993 a fifth journal titled 'Physical Review E' was introduced. [18] For this purpose, the Web of Science (WoS) -core collection database of the Clarivate Analytics has been consulted during the last week of October, 2019and following advanced query strings have been applied.Publication Name: ( The search has retrieved total 9,920 records comprising of article (9,823), editorial materials (20), correction (13), retracted publication (1), review (49) and letter (15). Out of the total publications, only journal articles (9,823) have been selected and shortlisted for the study. Later, the data have also been analysed to get desired output as specified in the objectives of the study. Tables and figures have been used to interpret the data. In addition, for measuring citation impact, different indices like h-index [20] and A-index [21] have been applied.

RESULTS
The following sub-sections categorize and demonstrate 9,823 research articles on various aspects like chronological break-up, source journal, collaboration trend, authorship, collaborating country, institution and citation pattern.

Triennial period wise distribution of articles
Further insights can be drawn by examining the details from Table 3 which shows the triennial period wise distribution of articles and corresponding collaboration output. The Indian scientists contributed total 9,823 articles to five source journals during 2004 to 2018. Of these, 4,815 articles (49.02%) were produced from national collaborations while international collaborations occurred in 5,008 articles (50.98%). Highest number of 2,659 articles (27.07%) outputted during the year 2016-18 followed by the preceding year, 2013-15 having 2241 articles (22.81%). It is observed from Figure 1 that an increasing trend has been seen in total contributions, national collaborations as well as international collaborations.

Collaboration wise distribution of articles
Collaboration wise output of articles and corresponding citation impact has been revealed in the Table 5. Out of total 9,823 articles, majority of the articles, i.e. 5,008 produced from international collaboration while 4,815 articles (49.02%) produced from national collaboration. Maximum international collaboration i.e. 59.09% occurred in the sub-field of 'particles, fields, gravitation and cosmology' (PRD journal) followed by 'condensed matter and materials physics' (PRB journal). Similarly, highest numbers of national collaborative output were evidenced in the 'statistical, nonlinear, biological and soft matter

Authorship distribution
Authorship pattern in research articles of different journals have been illustrated in the Table 6. Out of total 9,823 articles, majority of 2336 articles (23.8%) were produced by three-authored, followed by two-authored with 2299 articles (23.40%) and four-authored with 1426 articles (14.52%). It is significant to note that more than 10 authored produced 1565 articles which occupied 15.93% share. Figure 2  Country wise collaboration output and scholarly impact Focus area wise contribution of leading collaborating countries Table 8 highlights the leading 10 collaborated countries' contribution in the five focus areas of the source journals during 2004-2018. The five Physical Review journals focus particular field of physics. In all the five sub-fields of Physics, the USA and Germany lead among the collaborating countries and placed 1 st and 2 nd rank respectively. Apart from these, collaboration with the France scientists were also strong during the period and secured 3 rd rank in three sub-areas i.e. 'condensed matter and materials physics', 'nuclear physics' and 'statistical, non-  linear, biological and soft matter physics'. Alternatively, Canada ranked 3 rd position in the sub-area of 'atomic, molecular, optical physics and quantum information' while Russia secured the 3 rd place in 'particles, fields, gravitation and cosmology' sub-area.    ACPP= Average citations per paper; AC 100 = Number of articles received at least 100 or more citations    Moreover, international collaborative publications occupied 50.98% share having 5008 articles that also attracted larger citations impact compared to national collaborative output. Three-authored contributed majority of 23.8% share of total contributions and more than 10 authored accounted15.93% of total articles. Out of total 103 collaborating countries, USA ranked the leading position followed by Germany and France. However, collaborating articles with Brazil gained wider citation impact. The collaboration effort with the USA and Germany dominated in all the five focus areas whereas France also produced significant collaboration output and secured 3 rd rank in three sub-areas of physics.

Citation pattern
The Tata

DISCUSSION AND CONCLUSION
In last 15 years, the Indian scientists contribute significant number of articles in reputed journals of APS and the trend has been increasing year by year. Further, highest number of research articles published on the sub-areas of 'particles, fields, gravitation and cosmology' followed by 'condensed matter and materials physics'. In physics discipline, international collaboration trend slightly dominates over national collaborative effort and the trend is getting momentum. It is evident from the study that India is one of the leading countries in terms of contribution in high impact source journals of APS. It may also be argued that the Indian scientists are producing quality scientific output and have gained excellence in physical sciences research. Further, the collaboration phenomenon in research output is balanced and has showed strong interinstitutional collaboration network at the national level along with apparent international collaboration linkage.  In this contest, it is worth noting that the international experimental consortia are now playing an imperative role in India's high-energy physics research. The Indian scientists are now producing significant share of internationally collaborative papers under the international experimental research groups like ALICE, [22] Belle, [23] BaBar, [24] CMS [25] etc. that facilitate particle collider as a primary scientific research instruments. [26] The collider is the world's most complex technology that accelerates particles to very high kinetic energies and let them collide from opposite directions in the center of the detector. [26] This technology needs massive fund for development and maintenance of the infrastructure and also demands expertise from different professional communities like engineers, technicians, physicists.The scientists from membership institutions in different countries across the world team up and collaborate for research purposes in high-energy experiments. Through this initiative, the institutional scientists may participate in the global level scientific research projects for sharing fund, infrastructure and expertise. [27] Additionally, this joint venture also helps in enhancing scientific capability and country's knowledge base. Hope, these finding will encourage India's higher education as well as research institutions in identifying where we stand in outstanding research journals publication picture in comparison with others.