Air pollution research: visualization of research activity using density-equalizing mapping and scientometric benchmarking procedures

Background: Due to constantly rising air pollution levels as well as an increasing awareness of the hazardousness of air pollutants, new laws and rules have recently been passed. Although there has been a large amount of research on this topic, bibliometric data is still to be collected. Thus this study provides a scientometric approach to the material published on this subject so far. Methods: For this purpose, data retrieved from the "Web of Science" provided by the Thomson Scientific Institute was analyzed and visualized both with density-equalizing methods and classic data-processing methods such as tables and charts. Results: For the time span between 1955 and 2006, 26,253 items were listed and related to the topic of air pollution, published by 124 countries in 24 different languages. General citation activity has been constantly increasing since the beginning of the examined period. However, beginning with the year 1991, citation levels have been rising exponentially each year, reaching 39,220 citations in the year 2006. The United States, the UK and Germany were the three most productive countries in the area, with English and German ranked first and second in publishing languages, followed by French. An article published by Dockery, Pope, Xu et al. was both the most cited in total numbers and in average citation rate. J. Schwartz was able to claim the highest total number of citations on his publications, while D.W. Dockery has the highest citation rate per publication. As to the subject areas the items are assigned with, the most item were published in Environmental Sciences, followed by Meteorology & Atmospheric Sciences and Public, Environmental & Occupational Health. Nine out of the ten publishing journals with more than 300 entries dealt with environmental interests and one dealt with epidemiology. Conclusions: Using the method of density-equalizing mapping and further common data processing procedures, it can be concluded that scientific work concerning air pollution and related topics enjoys unbrokenly growing scientific interest. This can be observed both in publication numbers and in citation activity

Mobile Air Quality Studies (MAQS) - an international project

Due to an increasing awareness of the potential hazardousness of air pollutants, new laws, rules and guidelines have recently been implemented globally. In this respect, numerous studies have addressed traffic-related exposure to particulate matter using stationary technology so far. By contrast, only few studies used the advanced technology of mobile exposure analysis. The Mobile Air Quality Study (MAQS) addresses the issue of air pollutant exposure by combining advanced high-granularity spatial-temporal analysis with vehicle-mounted, person-mounted and roadside sensors. The MAQS-platform will be used by international collaborators in order 1) to assess air pollutant exposure in relation to road structure, 2) to assess air pollutant exposure in relation to traffic density, 3) to assess air pollutant exposure in relation to weather conditions, 4) to compare exposure within vehicles between front and back seat (children) positions, and 5) to evaluate "traffic zone"- exposure in relation to non-"traffic zone"-exposure. Primarily, the MAQS-platform will focus on particulate matter. With the establishment of advanced mobile analysis tools, it is planed to extend the analysis to other pollutants including including NO2, SO2, nanoparticles, and ozone

Visualization of research activity using density-equalizing mapping and scientometric benchmarking procedures

Seit der ersten gezielten Nutzung von Feuer durch den Menschen spielt anthropogene Luftverunreinigung eine Rolle, und spätestens seit Beginn der Industrialisierung von Gesellschaften ist sie zu einem schwerwiegenden Problem geworden. Verunreinigte Luft ist eine Gesundheitsgefährdung, die die gesamte Erdbevölkerung betrifft, da sie an Staatsgrenzen nicht stoppt. Bestrebungen zur Verbesserung der Luftqualität zielen dabei vor allem auf die anthropogene Luftverschmutzung als einzigen beeinflussbaren Faktor ab und sollten möglichst überregional gestaltet werden. Hauptursachen für anthropogene Luftverunreinigungen sind der Straßenverkehr als mobile Quelle und Prozesse der Energieerzeugung und Industrie als stationäre Quellen. In dieser Arbeit wird erstmals eine szientometrische Analyse der Forschungsaktivität zum Thema Luftverschmutzung und hier besonders zur Verunreinigung durch Feinstaub und Schwefeldioxid durchgeführt. Dabei werden Artikel analysiert, die in den Online-Datenbanken „PubMed“ und „Web of Science“ erfasst sind. Zum Thema Feinstaub und Schwefeldioxid wird innerhalb der Ergebnisse zur Luftverschmutzung gesucht („Web of Science“), bzw. die Suche über die MeSH- Database mit der zur Luftverschmutzung verknüpft („PubMed“). Zur Datenauswertung und bildlichen Darstellung werden teilweise selbst entwickelte Programme genutzt, internationale Übersichten zu Veröffentlichungsanzahlen und Zitationsraten werden mit der Density-Equalizing-Methode dargestellt. Die Analyse ergibt im Zeitraum von 1955 bis 2006 im „Web of Science“ 26.253 und bei „PubMed“ 28.416 Veröffentlichung für Luftverschmutzung, 3567 bzw. 2738 Publikationen zum Feinstaub und 1440 bzw. 1068 Datenbankeinträge für Schwefeldioxid. Die Veröffentlichungszahlen steigen im „Web of Science“ innerhalb des Analysezeitraums konstant an, während sich in „PubMed“ Mitte der 1970er Jahre eine Spitze in den jährlichen Publikationszahlen zeigt; beiden Datenbanken ist ein rasanter Anstieg der Veröffentlichungszahlen ab Anfang der 1990er Jahre gemeinsam. So steigen auch die Zitierungen der Artikel pro Jahr ab 1991 an, jedoch überproportional zu den Publikationszahlen; dies gilt für alle drei Analysen und ist vor allem im Zusammenhang mit der Einführung des World Wide Web für die Öffentlichkeit Anfang der 1990er Jahre sowie einer öffentlich entbrannten Diskussion zur Luftreinheit Anfang der 1990er Jahre zu sehen. Dass Englisch die derzeitige Sprache der Wissenschaft ist, bestätigt die Tatsache, dass 96% (80% für Feinstaub und 97% für Schwefeldioxid) der Publikationen in englischer Sprache verfasst sind. Weitere häufiger genutzte Sprachen sind Deutsch und Französisch. Der größte Anteil der Publikationsaktivität ist den USA zuzuschreiben (38% für Luftverschmutzung, 40% für Feinstaub und 30% für Schwefeldioxid). So gilt auch die höchste Anzahl an Zitierungen US-amerikanischen Veröffentlichungen; bei der Errechnung der Zitationsraten treten zunächst Länder mit geringen Publikationszahlen und Teilnahme an großen internationalen Studien in den Vordergrund, nach Aufdecken dieses statistischen Mangels zeigen sich europäische Staaten (Feinstaub, Schwefeldioxid) und Neuseeland vor südamerikanischen Ländern (Luftverschmutzung) führend. Angesichts der hohen Dichte so genannter Megastädte im asiatischen Raum erscheint die Abwesenheit von asiatischen Veröffentlichungen unter den häufig zitierten verwunderlich. Unter den produktivsten Autoren finden sich hauptsächlich US-amerikanische, so auch der meist publizierende, J. Schwartz, daneben auch europäische und ein kanadischer. Zur Thematik Schwefeldioxid überwiegt der Anteil der europäischen Autoren. Die Anzahl der ihnen zugeordneten Veröffentlichungen korreliert weder mit der Anzahl der Listungen als Erstautor noch mit dem für sie errechneten h-Index. Bei näherer Betrachtung ist der Hauptanteil der Zitierungen ihrer Werke auf Selbstzitierungen oder bevorzugte Zitate von durch Kooperationen mit anderen Autoren entstandenen Werken zurückzuführen. Hier kann von einer bewussten Einflussnahme auf eigene bibliometrische Werte ausgegangen werden, was ein häufiges Phänomen in der Wissenschaft darstellt. Die mit Abstand häufigste Veröffentlichungsform ist der Artikel. Die Forschungsgebiete der produktivsten Zeitschriften setzen sich hauptsächlich aus umweltwissenschaftlichen Themen zusammen, hier sind in allen drei Analysen für „Atmospheric Environment“ die meisten Erscheinungen eingetragen. Weiterhin findet sich eine Zeitschrift mit epidemiologischem Schwerpunkt und zwei mit medizinischen Inhalten (respiratorisches System). Die Impact Factors korrelieren nicht mit der Produktivität der Zeitschriften, die Werte für Cited Half-Life und Immediacy Index deuten auf nicht schnelllebige Wissenschaftsfelder hin. Die Ergebnisse der Zeitschriftenanalyse widerspiegelnd, sind unter den forschenden Fachgebieten die Umweltwissenschaften am produktivsten. Die vier relevanten medizinischen Fachbereiche geben die schon bei den Zeitschriften auffallende Unterrepräsentanz von gesundheitlichen Themen wieder; gleichzeitig ist die schon erfolgte Aufteilung in Unterthemen zu beachten, während die Umweltwissenschaften ein großes Themengebiet darstellen. Unter den analysierten Organsystemen wurde der Lunge die größte Aufmerksamkeit geschenkt, was sich angesichts ihrer Funktion als Eintrittspforte von u. a. Luftschadstoffen einfach nachvollziehen lässt. Auch andere nennenswerte Organsysteme zeichnen sich durch direkten Luftkontakt bzw. unmittelbare funktionelle Nähe zum respiratorischen System aus. Hohe Publikationszahlen für Luftverschmutzung durch Feinstaub im Zusammenhang mit der Leber lassen sich durch kürzlich angenommene funktionelle Schädigungszusammenhänge über eine Rechtsherzinsuffizienz erklären.Ever since the first purposeful utilization of fire by humankind, anthropogenic air pollution has been an issue. At least by the beginning of the industrialization it has become a severe problem. Today, the main causes of anthropogenic air pollution are road traffic (a “mobile” source), and processes in energy production and industry (“stationary” sources). Efforts to improve air quality are mainly aimed at anthropogenic air pollution, as it is the only susceptible factor. Polluted air is a health hazard of concern for the world population as a whole, since it does not stop at national borders. Therefore, efforts towards air quality imp ovement should be organized at a supra-regional level, when feasibility is indicated. In this paper, the first scientometric analysis of the research activity concerning the field of air pollution is accomplished, with particular attention to particulate matter and sulfur dioxide. Articles in the online databases “PubMed” and “Web of Science” are analyzed. Results for particulate matter and sulfur dioxide are retrieved from the sum of results for the air pollution analysis (“Web of Science”), or linked to the same by the MeSH-database (“PubMed”). In part, proprietary program codes are used to evaluate and illustrate data. International diagrams to demonstrate publication numbers and citation rates are generated by means of density-equalizing mapping to demonstrate publication numbers and citation rates. For the time span 1955-2006, the analysis shows 26,253 results in “Web of Science” and 28,416 in “PubMed” for air pollution. More specifically, for particulate matter, “Web of Science” lists 3567 publications while “PubMed” 2738 entries; for sulfur dioxide 1440 and 1068 publications respectively. During the analysis period, the number of publications increased in “Web of Science” over time, whereas in “PubMed” a peak in yearly publications occurred in the mid-1970s. However, both databases display a rapid slope in publication numbers at the beginning of the 1990s. Therefore, citation numbers rise beginning in 1991, too, but disproportionately high to publications. This is applicable for all three analyses and is to be mainly ascribed to the implementation of the World Wide Web to the public in the beginning of the 1990s as well as to a public discussion about air quality beginning in the early 1990s. The fact that 96% of the publications are written in English (80% for particulate matter and 97% for sulfur dioxide) supports the notion that English has become the main language for scientific literature. Other frequently used languages are German and French. The largest part of publication activity is attributable to research in the USA (38% for air pollution, 40% for particulate matter and 30% for sulfur dioxide). Therefore the highest numberof citations is found for US-American publications; calculating the citation rates, countries with low publication numbers participating in large international studies are on top of the agenda at first. Eliminating this statistical deficiency, European states (particulate matter, sulfur dioxide) and New Zealand (air pollution) are leading ahead of South American countries. Regarding the high density of so-called mega-cities in the Asian area, the lack of Asian publications among the frequently cited seems rather remarkable. Mainly US-Americans are to be found among the most productive authors including the most publishing one, J. Schwartz, alongside with Europeans and one Canadian author. Regarding the topic of sulfur dioxide, European authors are prevailing. Publication numbers neither correlate with the number of entries as first author nor with the h-indexes. Under closer inspection, the largest fraction of citations is to be ascribed to self- citations or preferential citations of papers that derive from co-operations with other authors. Here, an intentional influence on bibliometric accounts can be assumed, which is a common phenomenon in science. The article is by far the most frequent document type. The most productive journals‟ subject areas mainly consist of themes originating from the environmental sciences. Most entries are papers from “Atmospheric Environment” in all three analyses. Furthermore, there is one journal with an epidemiological emphasis and two journals with medical content (respiratory system). The impact factors do not correlate with the journals‟ productivity; values for cited half-life and immediacy index do not suggest fast moving fields of science. Mirroring the results of the journal analysis, environmental sciences are the most productive among the researching subject areas. The fact that there are four relevant medical fields reflects that health-related topics are underrepresented. This was already shown in the journals‟ analysis. At the same time, there has to be some attention paid to the fact that the medical topics are partitioned into sub-themes, while the environmental sciences are a large field containing many possible sub-themes. The most attention among the analyzed organ systems is paid to the lung, which is easily understandable, considering its function as the entrance for air pollutants. Other relevant organ systems are characterized by direct air contact or immediate functional closeness to the respiratory system. High publication numbers regarding particulate air pollution in combination with the liver can be explained by recently assumed functional coherence in damaging mechanisms by means of a right heart insufficiency

Adenosquamous versus adenocarcinoma of the pancreas: a population-based outcomes analysis.

BackgroundPancreatic adenosquamous carcinoma has historically been characterized as having a more aggressive clinical course than ductal adenocarcinoma. The natural history of this disease, however, is essentially unknown.MethodsWe evaluated the clinical characteristics of all patients with pancreatic adenosquamous carcinoma recorded in the California Cancer Registry 2000-2007 and compared them to those of patients with ductal adenocarcinoma.ResultsNinety-five patients with pancreatic adenosquamous carcinoma and 14,746 patients with ductal adenocarcinoma were identified. Demographics were similar between subtypes (p > 0.05). Disease stage at presentation was also similar; over 50% of each diagnostic group presented with metastatic disease (p = 0.62). Surgical resection was more common among patients with locoregional adenosquamous carcinoma than adenocarcinoma (p = 0.0004), but rates of adjuvant therapy administration were similar (p > 0.05). The cohorts' median overall survival durations were similar in a Cox proportional hazards model (p = 0.45); overall survival was also similar when only patients with resected disease were considered (p = 0.65). Early stage, resection and receipt of radiation or chemotherapy were favorable independent prognostic factors among patients with adenosquamous carcinoma. The median overall survival duration of patients with resected adenosquamous carcinoma was 12 months (95% CI, 8-52).ConclusionsAdenosquamous carcinoma has a natural history similar to that of ductal adenocarcinoma when treated with prevalent clinical patterns of care

Air pollution research: visualization of research activity using density-equalizing mapping and scientometric benchmarking procedures

Abstract Background Due to constantly rising air pollution levels as well as an increasing awareness of the hazardousness of air pollutants, new laws and rules have recently been passed. Although there has been a large amount of research on this topic, bibliometric data is still to be collected. Thus this study provides a scientometric approach to the material published on this subject so far. Methods For this purpose, data retrieved from the "Web of Science" provided by the Thomson Scientific Institute was analyzed and visualized both with density-equalizing methods and classic data-processing methods such as tables and charts. Results For the time span between 1955 and 2006, 26,253 items were listed and related to the topic of air pollution, published by 124 countries in 24 different languages. General citation activity has been constantly increasing since the beginning of the examined period. However, beginning with the year 1991, citation levels have been rising exponentially each year, reaching 39,220 citations in the year 2006. The United States, the UK and Germany were the three most productive countries in the area, with English and German ranked first and second in publishing languages, followed by French. An article published by Dockery, Pope, Xu et al. was both the most cited in total numbers and in average citation rate. J. Schwartz was able to claim the highest total number of citations on his publications, while D.W. Dockery has the highest citation rate per publication. As to the subject areas the items are assigned with, the most item were published in Environmental Sciences, followed by Meteorology & Atmospheric Sciences and Public, Environmental & Occupational Health. Nine out of the ten publishing journals with more than 300 entries dealt with environmental interests and one dealt with epidemiology. Conclusions Using the method of density-equalizing mapping and further common data processing procedures, it can be concluded that scientific work concerning air pollution and related topics enjoys unbrokenly growing scientific interest. This can be observed both in publication numbers and in citation activity.</p

Adenosquamous versus adenocarcinoma of the pancreas: a population-based outcomes analysis.

BackgroundPancreatic adenosquamous carcinoma has historically been characterized as having a more aggressive clinical course than ductal adenocarcinoma. The natural history of this disease, however, is essentially unknown.MethodsWe evaluated the clinical characteristics of all patients with pancreatic adenosquamous carcinoma recorded in the California Cancer Registry 2000-2007 and compared them to those of patients with ductal adenocarcinoma.ResultsNinety-five patients with pancreatic adenosquamous carcinoma and 14,746 patients with ductal adenocarcinoma were identified. Demographics were similar between subtypes (p &gt; 0.05). Disease stage at presentation was also similar; over 50% of each diagnostic group presented with metastatic disease (p = 0.62). Surgical resection was more common among patients with locoregional adenosquamous carcinoma than adenocarcinoma (p = 0.0004), but rates of adjuvant therapy administration were similar (p &gt; 0.05). The cohorts' median overall survival durations were similar in a Cox proportional hazards model (p = 0.45); overall survival was also similar when only patients with resected disease were considered (p = 0.65). Early stage, resection and receipt of radiation or chemotherapy were favorable independent prognostic factors among patients with adenosquamous carcinoma. The median overall survival duration of patients with resected adenosquamous carcinoma was 12&nbsp;months (95% CI, 8-52).ConclusionsAdenosquamous carcinoma has a natural history similar to that of ductal adenocarcinoma when treated with prevalent clinical patterns of care