Density Equalizing Map Projections Research Articles

Global cervical cancer research: A scientometric density equalizing mapping and socioeconomic analysis.

Cervical cancer has caused substantial morbidity and mortality for millions of women over the past decades. While enormous progress has been made in diagnosis, prevention and therapy, the disease is still fatal for many women—especially in low-income countries. Since no detailed studies are available on the worldwide research landscape, we here investigated the global scientific output related to this cancer type by an established protocol. The “New Quality and Quantity Indices in Science” platform assessed all relevant cervical cancer research published in the Web of Science since 1900. A detailed analysis was conducted including country-specific research productivity, indicators for scientific quality, and relation of research activity to socioeconomic and epidemiologic figures. Visualization of data was generated by the use of density equalizing map projections. Our approach identified 22,185 articles specifically related to cervical cancer. From a global viewpoint, the United States of America was the dominating country in absolute numbers, being followed by China and Japan. By contrast, the European countries Sweden, Austria, and Norway were positioned first when the research activity was related to the population number. When the scientific productivity was related to annual cervical cancer cases, Scandinavian countries (Finland #1, Sweden #4, Norway #5, Denmark #7), the Alpine countries Austria (#2) and Switzerland (#6), and the Netherlands (#3) were leading the field. Density equalizing mapping visualized that large parts of Africa and South America were almost invisible regarding the global participation in cervical cancer research. Our data documented that worldwide cervical cancer research activity is continuously increasing but is imbalanced from a global viewpoint. Also, the study indicated that global and public health aspects should be strengthened in cervical carcinoma research in order to empower more countries to take part in international research activities.

Epidemiological Influences and Requirements of Global Childhood Obesity Research

Introduction: Obesity is classified as a global epidemic and judged to be the greatest public health threat in Western countries. The tremendously increasing prevalence rates in children lead to morbidity and mortality in adults. In many countries, prevalence has doubled since the 1980s. Other countries show a continuous increase or stagnate at a very high level. Given these regional differences, this study aims to draw a global world map of childhood obesity research, including regional epidemiological characteristics, to comprehensively assess research influences and needs. Methods: In addition to established bibliometric parameters, this study uses epidemiological data to interpret metadata on childhood obesity research from the Web of Science in combination with state-of-the-art visualization methods, such as density equalizing map projections. Results: It was not until the 1990s that belated recognition of the dangerous effects of childhood obesity led to an increase in the number of publications worldwide. In addition, our findings show that countries’ study output does not correlate with epidemiologic rates of childhood obesity. In contrast, the primary driver of the research efforts on childhood obesity appears to be largely driven government funding structures. Discussion/Conclusion: The geographical differences in the epidemiological background of childhood obesity complicate the implementation of transnational research projects and cross-border prevention programs. Effective realization requires a sound scientific basis, which is facilitated by globally valid approaches. Hence, there is a need for information exchange between researchers, policy makers, and private initiatives worldwide.

Mammography: density equalizing mapping of the global research architecture.

Since mammography belongs to the most important preventive techniques in modern medicine, this study maps the related worldwide research output, which encompasses quantitative and qualitative aspects of the scientific activity and socio-economic features. The New Quality and Quantity Indices in Science (NewQIS) computing platform identified all mammography-specific articles in the Web of Science within two time periods, from 1900 to 2014 (P1) and from 2015 to 2020 (P2), a combination of density-equalizing mapping projections (DEMP) and socio-economic benchmarking was applied for analysis. A total of 13,629 articles were retrieved. 8,744 articles were identified in P1 and 4,885 in P2. More than 100 articles were published annually since the 1980s. Regarding productivity and collaborative efforts, the United States was the leading nation in both evaluation periods. In our socioeconomic analysis, it was also ranked at the first place in P1 [72.68 mammography-related publications per GDP/capita (RGDP)]. The US was followed by the UK and Germany in P1 and by UK and India in P2. When population sizes were related to mammography research activities, Scandinavian countries and the Netherlands showed the highest research activity in P1 (e.g., Sweden: 31.89 publications per 1 million inhabitants). Gender analysis illustrated a relative dominance of female researchers in most countries with the exception of Japan. The global mammography research activity over the last century is paralleled by strong international collaborative efforts and follows largely economic figures and prevalence rates but displays distinct differences in comparison to the research landscape of other biomedical entities.

Breech Presentation - A scientiometric analysis of the global research output

ObjectiveAlthough breech presentations occur in 3–5% of term deliveries, the mode of delivery still remains a topic of debate. Hence, this study aimed to analyze the worldwide research output on breech presentation. All relevant publications issued in the Web of Science from 1900 to 2014 were assessed by an objective, standardized bibliometric procedure. Study designIn this retrospective, descriptive study, we used the computerized NewQIS platform, to identify publications by a specific search term and to analyze them regarding quantitative parameters (e.g., countries of origin, journals) as well as qualitative characteristics (e.g., citation rate, country-specific H-index). In addition to geographical aspects, chronological developments and collaboration networks were investigated. In order to visualize the results, anamorphic maps were generated by the innovative “density equalizing map projections”(DEMP) technology. ResultsA total of 1,438 original articles, reviews, "Letters" and "Abstracts" on breech presentation were identified. 86% of this work was written in English. The highest number and the most cited publications came from the US and Canada as well as Western European countries. Exceptions were Israel and South Africa that appeared among the leading countries. The collaboration network included 26 countries, dominated by the US and the UK. We also present a table of the 14 most cited publications in the world. SummaryThis study underlines that the mere total of only 1,438 publications on breech do not do justice to this relevant and controversially discussed topic. The global research output was dominated by the industrialized world. Developing and emerging countries are largely excluded from research activities. To minimize this imbalance and to foster scientific collaborations, future research on this topic needs to be planned and funded according to these shortcomings.

Ulcerative Colitis: A Critical Approach to the Global Research Output Employing Density-equalizing Mapping and Scientometric Methods.

Despite decades of effort, numerous aspects on ulcerative colitis (UC) remain unknown and require further investigation. Scientists experience numerous challenges to survey >40,000 items that have been published on UC since 1900, to evaluate their scientific impact or to identify collaborative networks publishing the most relevant work. Hence, no current, detailed and comprehensive knowledge regarding the worldwide research architecture of UC has been established until now. We conducted a scientometric study employing the previously validated NewQIS (New Quality and Quantity Indices in Science) platform to quantify the global research activity in the field of UC. Hereby, the total research productivity, scientific output of countries, individual institutions, authors, journals, their collaborative networks as well as semiqualitative aspects were assessed. Results were visualized via state-of-the-art density-equalizing mapping projections. The United States, Germany, and the United Kingdom play leading roles regarding scientific activity, multilateral and bilateral cooperations. Within the past decades, research on UC diversified into a field covering numerous subject areas. Recently published studies predict that the scientific progress will be mainly depending on international cooperations; we can confirm that development by now. Scientometrics proofed to be a useful methodical approach to evaluate quantitative and semiqualitative aspects regarding UC. Also, we conclude that the influence of international cooperations on the scientific progress in the field of UC is constantly progressing.

Global Risk Factor Evaluation of Obstructive Sleep Apnoea in Relation to Research Activity and Socio-Economic Factors

Background: Obstructive Sleep Apnoea (OSA) is emerging as global health epidemic and is facing a rising prevalence especially due to the obesity pandemic. However, comprehensive global prevalence data is still lacking, and global OSA research in terms of activity, quality, and socio-economic characters has not yet been elucidated. Methods: Using the NewQIS platform, bibliometric techniques were combined with socio-economic benchmarks, a global health estimate report (GATHER statement), and density-equalizing-mapping-projections (DEMP). Findings: OSA publications increased exponentially since 1990/91. The USA was identified as leading country and at the centre of the international OSA research arena. Generally, the countries’ OSA research performance correlated with their overall biomedical output and economic strength with the exception of China, India, and Russia. Countries of the Middle East appeared with the highest risk of OSA (objective multivariable apnoea risk index) while exhibiting only a very limited OSA performance. Analysis of the countries’ estimated population at risk of OSA (middleaged obese males) revealed a discrepancy between the countries’ estimated burden of disease and OSA research activity (awareness). Interpretations: Although observing a strong increase in the OSA activity over the years, a lack of awareness predominantly in developing countries was identified. Furthermore, our study presents discrepancies between the countries’ estimated OSA burden and OSA research performance not limited to low resource nations. Given the socioeconomic strain of OSA, strong efforts are needed to raise awareness, initiate prevention programs to reduce risk factors (obesity), and increase the availability of diagnostic tools and treatment, especially in developing countries. Funding Statement: None. Declaration of Interests: Dr. Groneberg has nothing to disclose. Doris Klingelhoefer has nothing to disclose. Rebekka K. Seeger-Zybok has nothing to disclose. Ethics Approval Statement: Not applicable.

Crohn's Disease: A Critical Approach to Publication Procedures and Citation Behavior of the Global Research Network.

Crohn's disease (CD) is an inflammatory bowel disease, which can lead to abdominal pain, weight loss, fatigue, severe diarrhea, and malnutrition. Despite enormous efforts and progress in diagnosis and therapy, there are still many aspects of uncertainty leading to an increasing scientific interest in this topic. As it is challenging to survey all articles regarding CD and to measure their scientific importance, this study uses reliable scientometric tools to evaluate the global research output on CD related to quantitative and qualitative aspects and in chronological and geographical context. We conducted a scientometric analysis to assess all global research activity on CD from 1900 until 2013. We analyzed the research output of countries, individual institutions, journals, authors and their collaborative networks and depicted our findings by density-equalizing map projections. The worldwide research architecture indicated that the United States, the United Kingdom, Germany, and France play leading role regarding scientific activity, h-indices, multilateral and bilateral cooperations. There is a dramatic increase of collaborative publications since the 1990s, which underlines recent studies pronouncing that the scientific progress will be mainly depending on international cooperations. We conclude that the field of CD is constantly progressing, in which the influence of international cooperations on the scientific productivity is of major and growing importance. North American and Western European nations constitute the scientific leaders in the field of CD whereas developing or underdeveloped countries did not exhibit considerable research productivity.

Fast flow-based algorithm for creating density-equalizing map projections

Cartograms are maps that rescale geographic regions (e.g., countries, districts) such that their areas are proportional to quantitative demographic data (e.g., population size, gross domestic product). Unlike conventional bar or pie charts, cartograms can represent correctly which regions share common borders, resulting in insightful visualizations that can be the basis for further spatial statistical analysis. Computer programs can assist data scientists in preparing cartograms, but developing an algorithm that can quickly transform every coordinate on the map (including points that are not exactly on a border) while generating recognizable images has remained a challenge. Methods that translate the cartographic deformations into physics-inspired equations of motion have become popular, but solving these equations with sufficient accuracy can still take several minutes on current hardware. Here we introduce a flow-based algorithm whose equations of motion are numerically easier to solve compared with previous methods. The equations allow straightforward parallelization so that the calculation takes only a few seconds even for complex and detailed input. Despite the speedup, the proposed algorithm still keeps the advantages of previous techniques: With comparable quantitative measures of shape distortion, it accurately scales all areas, correctly fits the regions together, and generates a map projection for every point. We demonstrate the use of our algorithm with applications to the 2016 US election results, the gross domestic products of Indian states and Chinese provinces, and the spatial distribution of deaths in the London borough of Kensington and Chelsea between 2011 and 2014.

Polycystic ovary syndrome: analysis of the global research architecture using density equalizing mapping

Polycystic ovary syndrome (PCOS) is the most common cause of female infertility worldwide. Although the related research output is constantly growing, no detailed global map of the scientific architecture has so far been created encompassing quantitative, qualitative, socioeconomic and gender aspects. We used the NewQIS platform to assess all PCOS-related publications indexed between 1900 and 2014 in the Web of Science, and applied density equalizing mapping projections, scientometric techniques and economic benchmarking procedures. A total of 6261 PCOS-specific publications and 703 international research collaborations were found. The USA was identified as the most active country in total and collaborative research activity. In the socioeconomic analysis, the USA was also ranked first (25.49 PCOS-related publications per gross domestic product [GDP]/capita), followed by the UK, Italy and Greece. When research activity was related to population size, Scandinavian countries and Greece were leading the field. For many highly productive countries, gender analysis revealed a high ratio of female scientists working on PCOS with the exception of Japan. In this study, we have created the first picture of global PCOS research, which largely differs from other gynaecologic conditions and indicates that most related research and collaborations originate from high-income countries.

Maternal depression research: socioeconomic analysis and density-equalizing mapping of the global research architecture.

Maternal depression can be accounted for one of the most common complications during pregnancy and the postpartum period affecting women all over the world. So far, no detailed map of the worldwide maternal depression research architecture has been constructed, which encompasses aspects of research activity, quality, and also socioeconomic features. Using the NewQIS platform, density-equalizing mapping projections, scientometric techniques, and economic benchmarking procedures were applied to evaluate global maternal depression research for the period between 1900 and 2012. In total, 7330 related publications and 3335 international collaborations were identified. The USA was the most active country concerning collaborations and total research activity. In the socioeconomic analysis of research activity in high-income countries, Australia was ranked first with an average of 412.05 maternal depression-related publications per 1000 billion US$ GDP (Q1), followed by the UK (Q1 = 373.51) and Canada (Q1 = 306.32). The group of upper-middle-income countries was led by South Africa (Q1 = 145.67), followed by Turkey (Q1 = 91.8). China authored 11.95 maternal depression-related publications per 1000 billion US$ GDP. The USA had the highest activity of maternal depression research per GDP in billion US$ per capita (Q2 = 60.86). When research activity was related to population size (Q3 = publications per Mio. inhabitants), Australia (Q3 = 26.44) was leading the field, followed by Norway (Q3 = 18.48). Gender analysis revealed a relatively high degree of female scientists involved in this field of research with pronounced differences between single subject areas. In summary, we here present the first picture of the global scientific development in maternal depression research over a period of more than 100years. The research landscape is clearly dominated by North American and Western European countries, with only minor contribution of Asian or South American countries.

World-wide architecture of osteoporosis research: density-equalizing mapping studies and gender analysis

Objective: While research activities on osteoporosis grow constantly, no concise description of the global research architecture exists. Hence, we aim to analyze and depict the world-wide scientific output on osteoporosis combining bibliometric tools, density-equalizing mapping projections and gender analysis.Method: Using the NewQIS platform, we analyzed all osteoporosis-related publications authored from 1900 to 2012 and indexed by the Web of Science. Bibliometric details were analyzed related to quantitative and semi-qualitative aspects.Results: The majority of 57 453 identified publications were original research articles. The USA and Western Europe dominated the field regarding cooperation activity, publication and citation performance. Asia, Africa and South America played a minimal role. Gender analysis revealed a dominance of male scientists in almost all countries except Brazil.Conclusion: Although the scientific performance on osteoporosis is increasing world-wide, a significant disparity in terms of research output was visible between developed and low-income countries. This finding is particularly concerning since epidemiologic evaluations of future osteoporosis prevalences predict enormous challenges for the health-care systems in low-resource countries. Hence, our study underscores the need to address these disparities by fostering future research endeavors in these nations with the aim to successfully prevent a growing global burden related to osteoporosis.

Magnetic resonance imaging. Density equalizing mapping analysis of global research architecture

Despite the great medical importance, there is still no comprehensive scientometric analysis regarding the results of magnetic resonance imaging (MRI) and the development of the importance for the healthcare system. This paper evaluated and analyzed the entire research publication results on the topic of MRI for the period 1981-2007 based on scientometric methods and parameters. A scientometric analysis (database: ISI Web of Science 1981-2007, search terms MRI and magnetic resonance imaging) was performed. The following parameters were analyzed: number of publications, countries of publication, number of citations, citation rate and collaborations, using various analytical and display techniques, including density equalizing map projections. Most of the 49,122 publications on MRI could be attributed to the USA (32.5 %), which also has the most cooperative collaborations. Within Europe, Germany (10.3 %) is the country with the highest number of publications followed by the UK (9.3 %). The western industrialized nations dominate over the rest of the world in terms of scientific developments of MRI. The thematic focus of the publications lies in the fields of radiology and neuroscience. In addition to the journal Neurology most scientific articles were published in Magnetic Resonance in Medicine and Circulation. The results show that the current trend is continuing and the scientific interest in MRI is continuously increasing.

Density equalizing mapping of obesity: analysis ofaglobalepidemic

Obesity is a chronic disease whose origin is determined by genetic factors as well as environmental influences. The prevalence has rapidly increased worldwide in the recent decades. This paper evaluated the research on obesity in the period of 1900 - 2009 in the ISI "Web of Science" by Thomson Reuters. For this purpose scientometric methods were used and the results were graphically illustrated by "Density Equalizing Map Projections". From 1900 till 2009 94.987 published items are the basis for the present qualitative and quantitative data analysis. The publication rates show an exponential growth indicating a pronounced research activity. Concerning the country comparison the United States has the highest number of publications and citations, the highest modified h-index and most academic institutions. This manuscript shows the first comprehensive scientometric data on obesity. In this research area, the United States is a leader and is located at the center of global collaborations.

Curare--a curative poison: a scientometric analysis.

IntroductionCurare is one of the best-examined neurotoxins of the world, which has empirically been used for centuries by American Indigenes. Research on curare has been performed much later, a global scientometric analysis on curare research or its derivates does not yet exist. This bibliometric analysis is part of the global NewQis-project and should illuminate both toxic and historic issues of research on curare.MethodsThe ISI Web of Science was searched for data covering 1900 to 2013 using a term which included as many original articles on curare as possible. 3,867 articles were found and analyzed for common bibliometric items such as the number of citations, language of the articles or the (modified) Hirsch-Index (h-index). Results are illustrated utilizing modern density equalizing map projections (DEMP) or beam diagrams.ResultsMost publications were located in North America and Europe. The USA has the highest number of publications as well as the highest h-index. The number of publications overall rose until the late 1990s and later decreased. Furthermore, sudden increases of research activity are ascribable to historic events, like the first use of curare as muscle relaxant during surgery.DiscussionThis scientometric analysis of curare research reflects several tendencies as previously seen in other bibliometric investigations, i.e. the scientific quality standard of North America and Europe. Research on curare decreased however, due to the declining attention towards this muscle relaxant. This work exemplifies also how scientometric methods can be used to illuminate historic circumstances immediately stimulating scientific research.

Analysis of the spatial distribution of cryptosporidiosis in AIDS patients in San Francisco using density equalizing map projections (DEMP)

Environmental transmission of cryptosporidiosis has occurred repeatedly in defined spatial areas during outbreaks of disease attributed, for example, to drinking water contamination. Little work has been done to investigate the possibility of cryptosporidiosis infection in defined spatial areas in non-outbreak (i.e., endemic) settings. This study applies a novel approach to the investigation of the spatial distribution of cryptosporidiosis in AIDS patients in San Francisco. Density equalizing map projection (DEMP) maps were created for nine race/ethnicity-age groups of AIDS patients based on census tract of residence. Additionally, census tracts with a “high density” of cryptosporidiosis cases were identified by applying smoothing techniques to the DEMP maps, and included as a covariate in multivariate Poisson regression analyses of other known risk factors for cryptosporidiosis. These analyses suggest: (1) cases of cryptosporidiosis among Black and Hispanic AIDS patients, but not among Whites, show a statistically significant non-random spatial distribution (p<0.05) even after adjustment for the underlying spatial distribution of AIDS patients for these demographic groups, and (2) the risk of residence in these high density census tracts, adjusted for other known risk factors, was not statistically significant (relative risk=1.27, 95% confidence interval 0.15, 10.53). These results do not support an independent effect of spatial distribution on the transmission of cryptosporidiosis among AIDS patients.

Use of a density equalizing map projection in analysing childhood cancer in four California counties.

In this study, 401 cases of childhood cancer in four California counties in 1980-1988 were analysed with the innovative methodology of density equalizing map projections. The data were originally collected and analysed by the California State Department of Health Services (DHS). In addition to the new analytic technique, the present analysis used population data more detailed and more accurate than those in the DHS analysis. The geographic boundaries of the 259 census tracts in the study area were adjusted according to population at risk so as to make population density everywhere constant; then the 401 case locations were plotted on the density equalized map. If risk is everywhere equal, the resulting distribution of cases should be uniform except for statistical variation. The metric used was a measure of the variability of the density of cases on the density equalized map. The same metric was calculated for independent samples of artificial cases, generated under the null hypothesis of equal risk. The slight geographic non-uniformity observed among the real cases is well within the limits of variation observed in the samples of artificial cases. In agreement with results published by DHS, we conclude that there is no evidence for geographic variation of risk among the cases studied. Subsets of the data, selected by age, sex, race, time period and cancer site, yielded similar negative results.

Use of density equalizing map projections (DEMP) in the analysis of childhood cancer in four California counties.

In studying geographic disease distributions, one normally compares rates among arbitrarily defined geographic subareas (for example, census tracts), thereby sacrificing the geographic detail of the original data. The sparser the data, the larger the subareas must be in order to calculate stable rates. This dilemma is avoided with the technique of density equalizing map projections (DEMP). Boundaries of geographic subregions are adjusted to equalize population density over the entire study area. Case location plotted on the transformed map should have a uniform distribution if the underlying disease rates are constant. The present report describes the application of the DEMP technique to 401 childhood cancer cases occurring between 1980 and 1988 in four California counties, with the use of map files and population data for the 262 tracts of the 1980 Census. A kth nearest neighbour analysis provides strong evidence for geographic non-uniformity in tract rates (p < 10(-4)). No such effect is observed for artificial cases generated under the assumption of constant rates. Work is in progress to repeat the analysis with improved population estimates derived from both 1980 and 1990 Census data. Final epidemiologic conclusions will be reported when that analysis is complete.