Software survey: VOSviewer, a computer program for bibliometric mapping. Scientometrics. 2010;84:523-538. [PMID: 20585380 PMCID: PMC2883932 DOI: 10.1007/s11192-009-0146-3]

Structure and Evolution of Mediterranean Forest Research: A Science Mapping Approach

This study aims at conducting the first science mapping analysis of the Mediterranean forest research in order to elucidate its research structure and evolution. We applied a science mapping approach based on co-term and citation analyses to a set of scientific publications retrieved from the Elsevier’s Scopus database over the period 1980–2014. The Scopus search retrieved 2,698 research papers and reviews published by 159 peer-reviewed journals. The total number of publications was around 1% (N = 17) during the period 1980–1989 and they reached 3% (N = 69) in the time slice 1990–1994. Since 1995, the number of publications increased exponentially, thus reaching 55% (N = 1,476) during the period 2010–2014. Within the thirty-four years considered, the retrieved publications were published by 88 countries. Among them, Spain was the most productive country, publishing 44% (N = 1,178) of total publications followed by Italy (18%, N = 482) and France (12%, N = 336). These countries also host the ten most productive scientific institutions in terms of number of publications in Mediterranean forest subjects. Forest Ecology and Management and Annals of Forest Science were the most active journals in publishing research in Mediterranean forest. During the period 1980–1994, the research topics were poorly characterized, but they become better defined during the time slice 1995–1999. Since 2000s, the clusters become well defined by research topics. Current status of Mediterranean forest research (20092014) was represented by four clusters, in which different research topics such as biodiversity and conservation, land-use and degradation, climate change effects on ecophysiological responses and soil were identified. Basic research in Mediterranean forest ecosystems is mainly conducted by ecophysiological research. Applied research was mainly represented by land-use and degradation, biodiversity and conservation and fire research topics. The citation analyses revealed highly cited terms in the Mediterranean forest research as they were represented by fire, biodiversity, carbon sequestration, climate change and global warming. Finally, our analysis also revealed the multidisciplinary role of climate change research. This study provides a first holistic view of the Mediterranean forest research that could be useful for researchers and policy makers as they may evaluate and analyze its historical evolution, as well as its structure and scientific production. We concluded that Mediterranean forest research represents an active scientific field.

50 Years of renal physiology from one man and the perfused tubule: Maurice B. Burg

Technical advancements in research techniques in science are made in slow increments. Even so, large advances from insight and hard work of an individual with a single technique can have astonishing ramifications. Here, we examine the impact of Dr. Maurice B. Burg and the isolated perfused renal tubule technique and celebrate the 50th anniversary of the publication by Dr. Burg and his colleagues of their landmark paper in the American Journal of Physiology in 1966. In this study, we have taken a scientific visualization approach to study the scientific contributions of Dr. Burg and the isolated perfused tubule preparation as determining research impact by the number of research students, postdoctoral fellows, visiting scientists, and national and international collaborators. Additionally, we have examined the research collaborations (first and second generation scientists), established the migrational visualization of the first generation scientists who worked directly with Dr. Burg, quantified the metrics indices, identified and quantified the network of coauthorship of the first generation scientists with their second generation links, and determined the citations analyses of outputs of Dr. Burg and/or his first generation collaborators as coauthors. We also review the major advances in kidney physiology that have been made with the isolated perfused tubule technique. Finally, we are all waiting for the discoveries that the isolated perfused preparation technique will bring during the next 50 years.

Progressive and self-limiting neurodegenerative disorders in Africa: a new prominent field of research led by South Africa but without strong health policy

INTRODUCTION

Neurodegenerative disorders are involved in mortality and morbidity of every country. A high prevalence is estimated in Africa. Neurodegenerative disorders are defined by a progressive or self-limiting alteration of neurons implied in specific functional and anatomical functions. It encompasses a various range of clinical disorders from self-limiting to progressive. Focus on public health policies and scientific research is needed to understand the mechanisms to reduce this high prevalence. We use bibliometrics and mapping tools to explore the area studies and countries involved in scientific research on neurodegenerative disorders in Africa.

METHODS

We used two databases: Web of Science and Pubmed. We analyzed the journals, most cited articles, authors, publication years, organizations, funding agencies, countries and keywords in Web of Science Core collection database and publication years and Medical Subject Headings in Pubmed database. We mapped the data using VOSviewer.

RESULTS

We accessed 44 articles published between 1975 and 2014 in Web of Science Core collection Database and 669 from Pubmed database. The majority of which were after 2006. The main countries involved in research on neurodegenerative disorders in Africa the USA, the United Kingdom, France and South Africa representing the main network collaboration. Clinical neurology and Genetics hereditary are the main Web of Science categories whereas Neurosciences and Biochemistry and Molecular Biology are the main Web of Science categories for the general search "neurodegenerative disorders" not restrained to Africa. This is confirmed by Medical Subject Headings analysis from Pubmed with one more area study: Treatment.

CONCLUSION

Neurodegenerative disorders research is leaded by South Africa with a network involving the USA, the UK, as well as African countries such Zambia. The chief field that emerged was on patient and hereditary as well as treatment. Public health policies were lacking fields in research whereas prevalence is estimated to be important in every country. New 17 sustainable development goals of the United Nations could help in this way.

Is the promotion of research reflected in bibliometric data? A network analysis of highly cited papers on the Clusters of Excellence supported under the Excellence Initiative in Germany

Under the Excellence Initiative, a number of Clusters of Excellence in Germany have been supported since 2006 and 2007—including each a limited number of cooperating institutions. The aim of the present study is to investigate whether support for Clusters of Excellence since 2006 and 2007 is reflected in bibliometric network data. For this purpose, a comparison is made between network data in the period before support started (2003–2005) and in the period after support started (2009–2011). For these two periods, a co-authorship network is generated (based on the funded institutions). This is based on publications which are among the 1 % most frequently cited publications in their respective fields and publication year and which have at least one author from Germany. As the results show, the outcomes this yields for life sciences and natural sciences differ from each other. Whereas natural sciences display an effect of establishment of Clusters of Excellence on the bibliometric networks, this was not true of life sciences. After establishment of the Clusters of Excellence, the network in natural sciences not only contained more institutions of a Cluster of Excellence, but these institutions were distributed across fewer bibliometric clusters in the network than before establishment. In other words the structure of the Clusters of Excellence was better reflected in the network.

International publication trends and collaboration performance of China in healthcare science and services research

Background

In recent years, China’s healthcare reforms and related studies have drawn particular global attention. The main objective of this study is to evaluate quantitatively the publication trends and collaboration performance of China in healthcare science and services (HSS) research.

Methods

Scientometric methods and visualization technology were used to survey the growth and development trends of HSS research based on the Web of Science publications during the past 15 years.

Results

China’s international publications on HSS research increased rapidly compared to those of the global HSS and Chinese scientific studies. Growth trends indicate that collaboration among countries, institutions and authors has also increased. China’s leading partners were all developed countries, such as the US, the UK, Australia and Canada, which have contributed to the majority of the joint publications. The academic impact of publications involving partners from European and American countries was relatively higher than those involving partners from Asian countries. Prominent institutions were universities that could be primarily classified into two groups, namely, Mainland China on the one hand and Hong Kong universities and foreign universities on the other. The most prominent actors were elite institutions, such as Peking University, Fudan University, Chinese University of Hong Kong, University of Hong Kong. The papers published by the Chinese Ministry of Health had relatively high academic impact, whereas those published by Mainland China universities alone had a lower academic impact compared to foreign cooperation papers. Issues related to the Chinese healthcare reform, priority diseases (e.g., breast cancer, HIV/AIDS, tuberculosis, etc.), health systems performance, quality of life and measurement tools, aging problems and research methods have been the most popular HSS topics in China in recent years.

Conclusions

Despite the extensive achievement of the Chinese HSS reforms and research, gaps and challenges remain to be addressed, including those related to health insurance and the effects of the evaluation of essential medicine systems, human resources training and allocation in the health sector, government hospitals reforms and health services systems remodeling. These findings could help scholars and decision-makers understand the current status and likely future trends of the Chinese HSS research, and help them select the most appropriate collaboration partners and policies.

Impact of host genetic polymorphisms on vaccine induced antibody response

Many host- and vaccine-specific factors modulate an antibody response. Host genetic polymorphisms, in particular, modulate the immune response in multiple ways on different scales. This review article describes how information on host genetic polymorphisms and corresponding immune cascades may be used to generate personalized vaccine strategies to optimize the antibody response.

What Is Citizen Science?--A Scientometric Meta-Analysis

CONTEXT

The concept of citizen science (CS) is currently referred to by many actors inside and outside science and research. Several descriptions of this purportedly new approach of science are often heard in connection with large datasets and the possibilities of mobilizing crowds outside science to assists with observations and classifications. However, other accounts refer to CS as a way of democratizing science, aiding concerned communities in creating data to influence policy and as a way of promoting political decision processes involving environment and health.

OBJECTIVE

In this study we analyse two datasets (N = 1935, N = 633) retrieved from the Web of Science (WoS) with the aim of giving a scientometric description of what the concept of CS entails. We account for its development over time, and what strands of research that has adopted CS and give an assessment of what scientific output has been achieved in CS-related projects. To attain this, scientometric methods have been combined with qualitative approaches to render more precise search terms.

RESULTS

Results indicate that there are three main focal points of CS. The largest is composed of research on biology, conservation and ecology, and utilizes CS mainly as a methodology of collecting and classifying data. A second strand of research has emerged through geographic information research, where citizens participate in the collection of geographic data. Thirdly, there is a line of research relating to the social sciences and epidemiology, which studies and facilitates public participation in relation to environmental issues and health. In terms of scientific output, the largest body of articles are to be found in biology and conservation research. In absolute numbers, the amount of publications generated by CS is low (N = 1935), but over the past decade a new and very productive line of CS based on digital platforms has emerged for the collection and classification of data.

Bonded-communities in HantaVirus research: a research collaboration network (RCN) analysis

Hantavirus, one of the deadliest viruses known to humans, hospitalizes tens of thousands of people each year in Asia, Europe and the Americas. Transmitted by infected rodents and their excreta, Hantavirus are identified as etiologic agents of two main types of diseases-Hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome, the latter having a fatality rate of above 40 %. Although considerable research for over two decades has been going on in this area, bibliometric studies to gauge the state of research of this field have been rare. An analysis of 2631 articles, extracted from WoS databases on Hantavirus between 1980 and 2014, indicated a progressive increase (R ² = 0.93) in the number of papers over the years, with the majority of papers being published in the USA and Europe. About 95 % papers were co-authored and the most common arrangement was 4-6 authors per paper. Co-authorship has seen a steady increase (R ² = 0.57) over the years. We apply research collaboration network analysis to investigate the best-connected authors in the field. The author-based networks have 49 components (connected clump of nodes) with 7373 vertices (authors) and 49,747 edges (co-author associations) between them. The giant component (the largest component) is healthy, occupying 84.19 % or 6208 vertices with 47,117 edges between them. By using edge-weight threshold, we drill down into the network to reveal bonded communities. We find three communities' hotspots-one, led by researchers at University of Helsinki, Finland; a second, led by the Centers of Disease Control and Prevention, USA; and a third, led by Hokkaido University, Japan. Significant correlation was found between author's structural position in the network and research performance, thus further supporting a well-studied phenomenon that centrality effects research productivity. However, it was the PageRank centrality that out-performed degree and betweenness centrality in its strength of correlation with research performance.

Can technology life-cycles be indicated by diversity in patent classifications? The crucial role of variety

In a previous study of patent classifications in nine material technologies for photovoltaic cells, Leydesdorff et al. (Scientometrics 102(1):629-651, 2015) reported cyclical patterns in the longitudinal development of Rao-Stirling diversity. We suggested that these cyclical patterns can be used to indicate technological life-cycles. Upon decomposition, however, the cycles are exclusively due to increases and decreases in the variety of the classifications, and not to disparity or technological distance, measured as (1 - cosine). A single frequency component can accordingly be shown in the periodogram. Furthermore, the cyclical patterns are associated with the numbers of inventors in the respective technologies. Sometimes increased variety leads to a boost in the number of inventors, but in early phases-when the technology is still under construction-it can also be the other way round. Since the development of the cycles thus seems independent of technological distances among the patents, the visualization in terms of patent maps, can be considered as addressing an analytically different set of research questions.

A Longitudinal Analysis of Publications on Maternal Mortality

BACKGROUND

The fifth Millennium Development Goal formulated by the WHO in 2000 aimed to reduce global maternal mortality by 75% in 2015. We studied the extent to which medical research has supported this by studying maternal mortality. We performed a bibliometric analysis of the literature on maternal mortality and of the development of this literature over time.

METHODS

We searched for publications on maternal mortality in the Web of Science database in the period 1994-2013. We visualised the subjects of these publications using a term map showing the most significant terms occurring in the titles and abstracts of publications on maternal mortality.

RESULTS

We identified 3794 publications on maternal mortality in Web of Science. The annual number increased from 87 in 1994 to 397 in 2013. The largest number of maternal mortality publications was found in the field of Obstetrics and Gynecology, followed by the Public, Environmental, and Occupational Health field (increase from 1994 until 2013 of 300% and 700%, respectively). In both fields, the number of maternal mortality publications has increased at a much higher rate than the overall number of publications in the field.

CONCLUSIONS

In line with the focus of the fifth Millennium Development Goal on reducing maternal mortality, during the past 20 years, there has been a steady increase in the amount of attention paid to maternal mortality in the medical literature. This is largely driven by an increase, mainly in recent years, in public health research on maternal mortality.

Dormitory of Physical and Engineering Sciences: Sleeping Beauties May Be Sleeping Innovations

A 'Sleeping Beauty in Science' is a publication that goes unnoticed ('sleeps') for a long time and then, almost suddenly, attracts a lot of attention ('is awakened by a prince'). The aim of this paper is to present a general methodology to investigate (1) important properties of Sleeping Beauties such as the time-dependent distribution, author characteristics, journals and fields, and (2) the cognitive environment of Sleeping Beauties. We are particularly interested to find out to what extent Sleeping Beauties are application-oriented and thus are potential Sleeping Innovations. In this study we focus primarily on physics (including materials science and astrophysics) and present first results for chemistry and for engineering & computer science. We find that more than half of the SBs are application-oriented. To study the cognitive environments of Sleeping Beauties we develop a new approach in which the cognitive environment of the SBs is analyzed, based on the mapping of Sleeping Beauties using their citation links and conceptual relations, particularly co-citation mapping. In this way we investigate the research themes in which the SBs are 'used' and possible causes of why the premature work in the SBs becomes topical, i.e., the trigger of the awakening of the SBs. This approach is tested with a blue skies SB and an application-oriented SB. We think that the mapping procedures discussed in this paper are not only important for bibliometric analyses. They also provide researchers with useful, interactive tools to discover both relevant older work as well as new developments, for instance in themes related to Sleeping Beauties that are also Sleeping Innovations.

Making Open Access work

Purpose

– The purpose of this paper is to provide an overview of one of the most important and controversial areas of scholarly communication: Open Access publishing and dissemination of research outputs. It identifies and discusses recent trends and future challenges for various stakeholders in delivering Open Access (OA) to the scholarly literature.

Design/methodology/approach

– The study is based on a number of interrelated strands of evidence which make up the current discourse on OA, comprising the peer-reviewed literature, grey literature and other forms of communication (including blogs and e-mail discussion lists). It uses a large-scale textual analysis of the peer-reviewed literature since 2010 (carried out using the VOSviewer tool) as a basis for discussion of issues raised in the OA discourse.

Findings

– A number of key themes are identified, including the relationship between “Green” OA (deposit in repositories) and “Gold” OA (OA journal publication), the developing evidence base associated with OA, researcher attitudes and behaviours, policy directions, management of repositories, development of journals, institutional responses and issues around impact and scholarly communication futures. It suggests that current challenges now focus on how OA can be made to work in practice, having moved on from the discussion of whether it should happen at all.

Originality/value

– The paper provides a structured evidence-based review of major issues in the OA field, and suggests key areas for future research and policy development.

Dynamics of a Global Zoonotic Research Network Over 33 Years (1980-2012)

OBJECTIVE

The increasing rate of outbreaks in humans of zoonotic diseases requires detailed examination of the education, research, and practice of animal health and its connection to human health. This study investigated the collaboration network of different fields engaged in conducting zoonotic research from a transdisciplinary perspective.

METHODS

Examination of the dynamics of this network for a 33-year period from 1980 to 2012 is presented through the development of a large scientometric database from Scopus. In our analyses we compared several properties of these networks, including density, clustering coefficient, giant component, and centrality measures over time. We also elicited patterns in different fields of study collaborating with various other fields for zoonotic research.

RESULTS

We discovered that the strongest collaborations across disciplines are formed among the fields of medicine; biochemistry, genetics, and molecular biology; immunology and microbiology; veterinary; agricultural and biological sciences; and social sciences. Furthermore, the affiliation network is growing overall in terms of collaborative research among different fields of study such that more than two-thirds of all possible collaboration links among disciplines have already been formed.

CONCLUSIONS

Our findings indicate that zoonotic research scientists in different fields (human or animal health, social science, earth and environmental sciences, engineering) have been actively collaborating with each other over the past 11 years.

Mapping epidemiology's past to inform its future: metaknowledge analysis of epidemiologic topics in leading journals, 1974-2013

An empiric perspective on what epidemiology has studied over time might inform discussions about future directions for the discipline. We aimed to identify the main areas of epidemiologic inquiry and determine how they evolved over time in 5 high-impact epidemiologic journals. We analyzed the titles and abstracts of 20,895 articles that were published between 1974 and 2013. In 5 time periods that reflected approximately equal numbers of articles, we identified the main topics by clustering terms based on co-occurrence. Infectious disease and cardiovascular disease epidemiology were the prevailing topics over the 5 periods. Cancer epidemiology was a major topic from 1974 to 2001 but disappeared thereafter. Nutritional epidemiology gained relative importance from 1974 to 2013. Environmental epidemiology appeared during 1996-2001 and continued to be important, whereas 2 clusters related to methodology and meta-analysis in genetics appeared during 2008-2013. Several areas of epidemiology, including injury or psychiatric epidemiology, did not make an appearance as major topics at any time. In an ancillary analysis of 6 high-impact general medicine journals, we found patterns of epidemiologic articles that were overall consistent with the findings in epidemiologic journals. This metaknowledge investigation allowed identification of the dominant topics in and conversely those that were absent from 5 major epidemiologic journals. We discuss implications for the field.