Brief Report: Gendered citation patterns among the scientific elite

Diversity in science is necessary to improve innovation and increase the capacity of the scientific workforce. Despite decades-long efforts to increase gender diversity, however, women remain a small minority in many fields, especially in senior positions. The dearth of elite women scientists, in turn, leaves fewer women to serve as mentors and role models for young women scientists. To shed light on gender disparities in science, we study prominent scholars who were elected to the National Academy of Sciences. We construct author citation networks that capture the structure of recognition among scholars’ peers. We identify gender disparities in the patterns of peer citations and show that these differences are strong enough to accurately predict the scholar’s gender. In contrast, we do not observe disparities due to prestige, with few significant differences in the structure of citations of scholars affiliated with high-ranked and low-ranked institutions. These results provide further evidence that a scholar’s gender plays a role in the mechanisms of success in science.     

Global citation inequality is on the rise

Citations are important building blocks for status and success in science. We used a linked dataset of more than 4 million authors and 26 million scientific papers to quantify trends in cumulative citation inequality and concentration at the author level. Our analysis, which spans 15 y and 118 scientific disciplines, suggests that a small stratum of elite scientists accrues increasing citation shares and that citation inequality is on the rise across the natural sciences, medical sciences, and agricultural sciences. The rise in citation concentration has coincided with a general inclination toward more collaboration. While increasing collaboration and full-count publication rates go hand in hand for the top 1% most cited, ordinary scientists are engaging in more and larger collaborations over time, but publishing slightly less. Moreover, fractionalized publication rates are generally on the decline, but the top 1% most cited have seen larger increases in coauthored papers and smaller relative decreases in fractional-count publication rates than scientists in the lower percentiles of the citation distribution. Taken together, these trends have enabled the top 1% to extend its share of fractional- and full-count publications and citations. Further analysis shows that top-cited scientists increasingly reside in high-ranking universities in western Europe and Australasia, while the United States has seen a slight decline in elite concentration. Our findings align with recent evidence suggesting intensified international competition and widening author-level disparities in science.

Science is a highly stratified social system. The distribution of scientific rewards is remarkably uneven, and a relatively small stratum of elite scientists enjoys exceptional privileges in terms of funding, research facilities, professional reputation, and influence (1–5). The so-called Matthew effect, well-documented in science (6–15), implies that accomplished scientists receive more rewards than their research alone merits, and recent evidence indicates a widening gap between the “haves” and the “have nots” of science in terms of salary levels (5), research funding (16), and accumulation of scientific awards (17).Inequality may foster creative competition in the science system (18, 19). However, it can also lead to a dense concentration of resources with diminishing returns on investment (intellectual and fiscal) (16, 20), and to monopolies in the marketplace of ideas (21, 22).The social processes that sort scientists into more or less prestigious strata are complex and multifaceted (1, 10, 23) and may be changing in response to external pressures such as globalization, the advent of new information technologies, and shifts in university governance models (3). However, a few common characteristics have always separated elite scientists from the rest of us, most notably their scientific output and visibility. Publications and citations are critical building blocks for status and success in science (23, 24), and the scientific elite accounts for a large share of what is published and cited.In 1926, Lotka observed that the publication frequencies of chemists followed an inverse-square distribution, where the number of authors publishing N papers would be ∼1/N² of the number of authors publishing one paper (25). Building on Lotka’s work, de Solla Price later went on to suggest that 50% of all publications were produced by a mere 6% of all scientists (26). More recent research demonstrates even larger disparities in citation distributions at the author level (2, 6, 11, 27, 28), but variations in citation concentration across disciplinary, institutional, and national boundaries remain uncertain. Further, it is unclear whether the observed inequalities in citation shares have intensified over time.Advances in author-disambiguation methods (29) allow us to investigate these questions on a global scale. We used a linked dataset of 4,042,612 authors and 25,986,133 articles to examine temporal trends in the concentration of citations at the author level, and differences in the degree of concentration across fields, countries, and institutions.Publication and citation data were retrieved from Clarivate’s Web of Science (WoS). We limited our focus to disciplines within the medical and health sciences, natural sciences, and agricultural sciences, where journal publication is the primary form of scholarly communication (Materials and Methods). We used a disambiguation algorithm to create publication profiles for all authors with five or more publication entries in WoS. The disambiguated dataset allowed us to measure developments in citation concentration from 2000 onward.Per-author citation impact was measured using field-normalized citation scores (ncs). ncs is calculated by dividing the raw per-paper citation scores with the average citation counts of comparable papers published in the same year and subfield. ncs was rescaled to account for citation inflation, represented here as nics. We report per-author cumulative citation impact based on a full and fractional counting. The full counting gives the sum of nics for all papers published by a scientist. The fractional counting also gives the sum of citations accrued by a scientist in all her papers, but divides the per-article citation scores with the number of contributors per paper. We use citation density plots and Gini coefficients to gauge trends in citation imbalance and concentration.     

Original research: Prioritisation of lower gastrointestinal endoscopy during the COVID-19 pandemic: outcomes of a novel triage pathway

ObjectiveThe 2-week-wait (2ww) referral pathway is used in England to fast-track patients with suspected colorectal cancer (CRC). A two-stage triage pathway was used to prioritise lower gastrointestinal (LGI) endoscopy for suspected CRC during the COVID-19 pandemic.MethodAll patients referred for an LGI endoscopy via a 2ww referral pathway between March 2020 and July 2020 were assessed. The first stage triaged patients to high, standard or low risk of CRC based on symptoms and faecal immunochemical test (FIT), and offered CT scans to those at high risk. The second stage, endoscopy prioritisation (EP), incorporated the CT results, FIT and symptoms to triage into four groups, EP1–EP4; with EP1 being the most urgent and EP4 the least. The primary outcome measure was CRC detection.Results514 patients were included. The risk of CRC was triaged as high in 190/514 patients (37%), standard in 274/514 patients (53%) and low in 50/514 (10%) patients. 422/514 patients (82%) underwent endoscopy with triage to EP1 in 52/422 (12%), EP2 in 105/422 (25%), EP3 in 210/422 (50%) and EP4 in 55/422 (13%). CRC was detected in 23 patients (5.4%). CRC was significantly more frequent in the EP1 group (23.1%, relative risk (RR)=16.2) and EP2 group (6.7%, RR=4.7) compared with EP3 group (1.4%). All CRC lesions were identified by CT imaging when performed prior to LGI endoscopy.ConclusionThis triage pathway designated 83% of patients with CRC to either EP1 or EP2. During a period of limited endoscopy provision, this pathway effectively prioritises endoscopy for those at greatest risk of CRC.     

The incidence and role of negative citations in science

Citations to previous literature are extensively used to measure the quality and diffusion of knowledge. However, we know little about the different ways in which a study can be cited; in particular, are papers cited to point out their merits or their flaws? We elaborated a methodology to characterize “negative” citations using bibliometric data and natural language processing. We found that negative citations concerned higher-quality papers, were focused on a study’s findings rather than theories or methods, and originated from scholars who were closer to the authors of the focal paper in terms of discipline and social distance, but not geographically. Receiving a negative citation was also associated with a slightly faster decline in citations to the paper in the long run.Scientific knowledge is a key input for economic prosperity (1–3) and evolves thanks to the complementary contributions of different scientists. The norms that regulate the scientific community coordinate this endeavor (4–6).Citation of previous work is one such norm and a major means of documenting the collective and cumulative nature of knowledge production. Citations allow for the establishment of credit and the identification of scientific paradigms and their shifts (7, 8); they measure the impact and quality of discoveries and, by extension, of a researcher, an institution, or a journal (9, 10). Studies rely on citation data also to analyze the diffusion of scientific ideas, the creation and evolution of scientific networks, and the role of top scientists and inventions (11–17).Less attention has been devoted to the different intentions behind a citation. In particular, although papers may often be cited because a current study is consistent with past work or builds upon it, a reference can sometimes be made to point out limitations, inconsistencies, or flaws that are even more serious. These “negative” citations may question or limit the scope and impact of a contribution, a scholar, or an entire line of research. Criticisms expressed through citations could also be part of the “falsification” process that, according to Karl Popper, characterizes science and could be a signal of the solidity of a field (18). For example, the recent criticisms and eventual dismissal of the evidence of gravitational waves and ultrafast expansion of the universe in the “big bang” were interpreted as developments in the study of the origins of the universe (19). Even for findings that are eventually confirmed, critiques may be beneficial in the process. For instance, the Copernican revolution benefited from and was refined by Tycho Brahe’s observations about inconsistencies in the heliocentric view, despite the eventual falsification of Brahe’s theory (20).A thorough classification and understanding of different types of citations, and in particular of negative citations—their incidence, distribution within research fields and across time, their location within a paper, and the connections that they establish between studies and scholars—is therefore a valuable exercise to understand the evolution of science. This enhanced classification may also offer current repositories of scholarly work (such as Google Scholar, PubMed, ISI Web of Science, and Scopus) an opportunity to improve their search and ranking algorithms; by extracting more information from citations, we can uncover more information, reject false knowledge more rapidly, and ultimately enhance the scientific discourse.Such a classification, however, is difficult to perform and would have been impossible just a few years ago. Recent advancements in natural-language processing (NLP) (21) and in the ability to parse and analyze large bodies of text, however, now allow us to reconstruct the context in which a citation was made, and therefore to understand why a given study was cited in the first place.We developed a method to identify citations that question the validity of previous results and to analyze their incidence and patterns to determine their role, relevance, and impact using bibliometric data, NLP techniques, and domain experts. In this study we provide evidence of (i) how negative citations are expressed, (ii) their incidence or frequency, (iii) the types of papers that receive these critiques and the types of papers that make the critiques, (iv) the parts of a study that are negatively cited (e.g., the theory, the results, the implications, etc.), (v) the relationships between the citing and cited authors, and (vi) the consequences of a negative citation in terms of future citations. To guarantee homogeneity of the analysis and define a feasible testing ground, the analysis in this paper was based on 15,731 full-text articles in the Journal of Immunology (1998–2007) and the 762,355 citations contained in those papers. Details of our procedures are in Materials and Methods and Supporting Information.     

Original research: Endoscopy training through the COVID-19 pandemic: maintaining procedural volumes and key performance standards

ObjectiveEndoscopy departments have experienced considerable challenges in the provision of endoscopy services since the start of the COVID-19 pandemic. Several studies have reported a reduction of procedures performed by trainee endoscopists during the pandemic. The aim of this study was to assess the impact on colonoscopy training and quality in an academic centre throughout successive waves of the pandemic.MethodsThis was a single-centre, retrospective, observational study comparing colonoscopies performed at a tertiary endoscopy centre in Ireland at different stages of the pandemic with those performed during a similar time frame prepandemic. Data were collected using electronic patient records. Primary outcomes were procedure volumes, adenoma detection rate and mean adenoma per procedure.ResultsIn the prepandemic period, 798 colonoscopies were performed. During the same period in 2020, 172 colonoscopies were performed. In 2021, during the third wave of the pandemic, 538 colonoscopies were performed. Percentages of colonoscopies performed by trainees were 46.0% (n=367) in 2019, 25.6% (n=44) in 2020 and 45.2% (n=243) in 2021. Adenoma detection rate was 21.3% in 2019, 38.6% in 2020 and 23.9% in 2021. Mean adenoma per procedure was 0.45 in 2019, 0.86 in 2020 and 0.49 in 2021. Caecal intubation rate was 90.74% in 2019, 90.9% in 2020 and 95.88% in 2021.ConclusionThe COVID-19 pandemic initially had a negative impact on overall colonoscopy volumes and training. Despite a reduction in procedural volume, key performance standards were maintained by trainees. Maintenance of hands-on training is essential to allow trainees achieve and retain competency in endoscopy.     

COVID-19 vaccine research and development: ethical issues

The achievements of vaccine research and development bring a hope to our societies that we may cope with the COVID-19 pandemic. There are two aspects that should be maintained in balance: the immediate necessity for speed of vaccine research and the inherent need for protection of research subjects, which is the foremost concern of research ethics. This narrative review highlights ethical issues in COVID-19 vaccine research and development that every stakeholder needs to be aware of and to consider.     

Original research: Insight from patients and healthcare professionals on the implementation of virtual clinics in patients with inflammatory bowel disease

IntroductionDuring COVID-19, the management of outpatient inflammatory bowel disease (IBD) changed from face-to-face (F2F) to telephone and video consultations across the UK. We surveyed patients with IBD and IBD healthcare professionals (HCPs) to evaluate the impact of this abrupt transition on patient and HCP satisfaction outcomes, including the barriers and enablers of this service.MethodsPatient satisfaction surveys were sent to patients who had a telephone consultation from May to July 2020. A second survey was sent to IBD HCPs across the UK. Questions from both surveys consisted of a mixture of multiple-choice options, ranking answers as well as short-answer questions.Results210 patients and 114 HCPs completed the survey. During COVID-19, there was a significantly greater use of telephone, video or a mixture of consultation. F2F consultations were consistently preferred by patients, with 50% of patients indicating they did not want the option of for video consultations. Patients were more likely to prefer a telephone consultation if they were stable and needed routine review. Significantly fewer HCPs (5.3%) intend to use F2F consultations alone, preferring the use of telephone (20.2%) or combinations of telephone/F2F (22.8%), telephone/video (4.4%) or combination of all three consultation types (34.2%). 63% indicated they intend to incorporate video consultations in the future.ConclusionTelephone and video consultations need to be balanced proportionately with F2F clinics to achieve both patient and HCP satisfaction. Further research needs to be done to explore the use of video medicine in patients with IBD.     

Original research: UK-wide study of the opinions of gastroenterology trainees: COVID-19, Shape of Training and the future workforce

IntroductionThe COVID-19 pandemic has disrupted training. Gastroenterology higher specialty training is soon to be reduced from 5 years to 4. The British Society of Gastroenterology Trainees Section biennial survey aims to delineate the impact of COVID-19 on training and the opinions on changes to training.MethodsAn electronic survey allowing for anonymised responses at the point of completion was distributed to all gastroenterology trainees from September to November 2020.ResultsDuring the first wave of the COVID-19 pandemic, 71.0% of the respondents stated that more than 50% of their clinical time was mostly within general internal medicine. Trainees reported a significant impact on all aspects of their gastroenterology training due to lost training opportunities and increasing service commitments. During the first wave, 88.5% of the respondents reported no access to endoscopy training lists. Since this time, 66.2% of the respondents stated that their endoscopy training lists had restarted. This has resulted in fewer respondents achieving endoscopy accreditation. The COVID-19 pandemic has caused 42.2% of the respondents to consider extending their training to obtain the skills required to complete training. Furthermore, 10.0% of the respondents reported concerns of a delay to completion of training. The majority of respondents (84.2%) reported that they would not feel ready to be a consultant after 4 years of training.ConclusionsReductions in all aspects of gastroenterology training were reported. This is mirrored in anticipated concerns about completion of training in a shorter training programme as proposed in the new curriculum. Work is now required to ensure training is restored following the pandemic.     

Universality of citation distributions: toward an objective measure of scientific impact

We study the distributions of citations received by a single publication within several disciplines, spanning broad areas of science. We show that the probability that an article is cited c times has large variations between different disciplines, but all distributions are rescaled on a universal curve when the relative indicator c_f = c/c₀ is considered, where c₀ is the average number of citations per article for the discipline. In addition we show that the same universal behavior occurs when citation distributions of articles published in the same field, but in different years, are compared. These findings provide a strong validation of c_f as an unbiased indicator for citation performance across disciplines and years. Based on this indicator, we introduce a generalization of the h index suitable for comparing scientists working in different fields.     

Risk reduction of hospitalisation and severe disease in vaccinated COVID-19 cases during the SARS-CoV-2 variant Omicron BA.1-predominant period,Navarre, Spain,January to March 2022

BackgroundAs COVID-19 vaccine effectiveness against SARS-CoV-2 infection was lower for cases of the Omicron vs the Delta variant, understanding the effect of vaccination in reducing risk of hospitalisation and severe disease among COVID-19 cases is crucial.AimTo evaluate risk reduction of hospitalisation and severe disease in vaccinated COVID-19 cases during the Omicron BA.1-predominant period in Navarre, Spain.MethodsA case-to-case comparison included COVID-19 epidemiological surveillance data in adults ≥ 18 years from 3 January–20 March 2022. COVID-19 vaccination status was compared between hospitalised and non-hospitalised cases, and between severe (intensive care unit admission or death) and non-severe cases using logistic regression models.ResultsAmong 58,952 COVID-19 cases, 565 (1.0%) were hospitalised and 156 (0.3%) were severe. The risk of hospitalisation was reduced within the first 6 months after full COVID-19 vaccination (complete primary series) (adjusted odds ratio (aOR): 0.06; 95% CI: 0.04–0.09) and after 6 months (aOR: 0.16; 95% CI: 0.12–0.21; p_comparison < 0.001), as well as after a booster dose (aOR: 0.06: 95% CI: 0.04–0.07). Similarly, the risk of severe disease was reduced (aOR: 0.13, 0.18, and 0.06, respectively). Compared with cases fully vaccinated 6 months or more before a positive test, those who had received a booster dose had lower risk of hospitalisation (aOR: 0.38; 95% CI: 0.28–0.52) and severe disease (aOR: 0.38; 95% CI: 0.21–0.68).ConclusionsFull COVID-19 vaccination greatly reduced the risk of hospitalisation and severe outcomes in COVID-19 cases with the Omicron variant, and a booster dose improved this effect in people aged over 65 years.     

《临床心电学杂志》载文被引分析研究

目的从文献引证的角度了解《临床心电学杂志》的学术水平和期刊质量。方法依据中国生物医学期刊引文数据库(CMCI),采用文献计量学方法对《临床心电学杂志》载文被CMCI来源期刊引用的情况进行统计分析及评价。结果载文被引1779次,单篇论文平均被引次数为3.24次,被引作者群的地域分布27个省、市和自治区,北京、上海、安徽等地区居于前列,有356种期刊引用该刊。结论该刊是我国心电学医学研究领域重要的信息源之一,是我国医学领域的主要核心期刊。     

COVID-19 pandemic: Pathophysiology and manifestations from the gastrointestinal tract

The pandemic of coronavirus disease 2019(COVID-19), caused by a newly identified β-coronavirus(SARS-CoV-2) has emerged as a dire health problem, causing a massive crisis for global health. Primary method of transmission was firstly thought to be animal to human transmission. However, it has been observed that the virus is transmitted from human to human via respiratory droplets. Interestingly, SARS-CoV-2 ribonucleic acid(RNA) has been isolated from patient stools, suggesting a possible gastrointestinal(GI) involvement. Most commonly reported clinical manifestations are fever, fatigue and dry cough. Interestingly, a small percentage of patients experience GI symptoms with the most common being anorexia, diarrhea, nausea and vomiting. The presence of viral RNA in stools is also common and fecal tests can be positive even after negative respiratory samples. The exact incidence of digestive symptoms is a matter of debate. The distribution of Angiotensin converting enzyme type 2 receptors in multiple organs in the body provides a possible explanation for the digestive symptoms' mechanism. Cases with solely GI symptoms have been reported in both adults and children. Viral RNA has also been detected in stool and blood samples, indicating the possibility of liver damage, which has been reported in COVID-19 patients. The presence of chronic liver disease appears to be a risk factor for severe complications and a poorer prognosis, however data from these cases is lacking. The aim of this review is firstly, to briefly update what is known about the origin and the transmission of SARS-CoV-2, but mainly to focus on the manifestations of the GI tract and their pathophysiological background, so that physicians on the one hand, not to underestimate or disregard digestive symptoms due to the small number of patients exhibiting exclusively this symptomatology and on the other, to have SARS-CoV-2 on their mind when the gastroenteritis type symptoms predominate.     

Top 50 cited articles on Covid-19 after the first year of the pandemic: A bibliometric analysis

Background & aimsIt has been just over a year since the Covid-19 pandemic started. The top 50 cited articles on this subject would help identify trends and focus on the research efforts.MethodsWe utilised e-utilities in PubMed to find publications on Covid-19 until the date of search on 7/2/21. The iCite website was used to find the top 50 citations of the output from the search strategy. We looked into their full text for the editorial dates, type of study, level of evidence, focus of the article and country of origin. We also counted the errata and comments on each of them.ResultsThe total number of citations of all 50 articles was 123,960, the highest being 10, 754 for a single article. Huang C was the most cited first author. They were published from week 4–17, with February being the month with most citations. Lancet was the most cited journal, having published 9 of the 50 articles. Majority belonged to level 3 of the evidence ladder and were retrospective studies. Thirty percent of them had an errata published and an average of 7 comments per article.ConclusionThe top 50 most cited articles identify the most impactful studies on Covid-19, providing a resource to educators while identifying trends to guide research and publishing efforts. There has been an explosion of publications and an unprecedented rate and number of citations within the first year for any single condition in the literature.     

Placental Pathology of COVID-19 with and without Fetal and Neonatal Infection: Trophoblast Necrosis and Chronic Histiocytic Intervillositis as Risk Factors for Transplacental Transmission of SARS-CoV-2

The mechanism(s) by which neonates testing positive for coronavirus disease 2019 (COVID-19) acquire their infection has been largely unknown. Transmission of the etiological agent, SARS-CoV-2, from mother to infant has been suspected but has been difficult to confirm. This communication summarizes the spectrum of pathology findings from pregnant women with COVID-19 based upon the infection status of their infants and addresses the potential interpretation of these results in terms of the effects of SARS-CoV-2 on the placenta and the pathophysiology of maternal-fetal infection. Placentas from pregnant women with COVID-19 and uninfected neonates show significant variability in the spectrum of pathology findings. In contrast, placentas from infected maternal-neonatal dyads are characterized by the finding of mononuclear cell inflammation of the intervillous space, termed chronic histiocytic intervillositis, together with syncytiotrophoblast necrosis. These placentas show prominent positivity of syncytiotrophoblast by SARS-CoV-2, fulfilling the published criteria for transplacental viral transmission as confirmed in fetal cells through identification of viral antigens by immunohistochemistry or viral nucleic acid using RNA in situ hybridization. The co-occurrence of chronic histiocytic intervillositis and trophoblast necrosis appears to be a risk factor for placental infection with SARS-CoV-2 as well as for maternal-fetal viral transmission, and suggests a potential mechanism by which the coronavirus can breach the maternal-fetal interface.