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Internationalization of pediatric sleep apnea research
International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
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Internationalization of pediatric sleep apnea research Mario Milkov * St. Petka Eye and Ear Clinic of Varna, 40 Slivnitsa Blvd, BG-9002 Varna, Bulgaria
A R T I C L E I N F O
A B S T R A C T
Article history: Received 14 September 2011 Received in revised form 7 November 2011 Accepted 8 November 2011 Available online 14 December 2011
Objective: Recently, the socio-medical importance of obstructive sleep apnea in infancy and childhood increases worldwide. The present investigation aims at analyzing the dynamic science internationalization in this narrow field as reflected in three data-bases and at outlining the most significant scientists, institutions and primary information sources. Methods: A scientometric study of data from a retrospective problem-oriented search on pediatric sleep apnea in three data-bases such as Web of Science, MEDLINE and Scopus was carried out. A set of parameters of publication output and citations was followed-up. Several scientometric distributions were created and enabled the identification of some essential peculiarities of the international scientific communications. Results: There was a steady world publication output increase. In 1972–2010, 4192 publications from 874 journals were abstracted in MEDLINE. In 1985–2010, more than 8100 authors from 64 countries published 3213 papers in 626 journals and 256 conference proceedings abstracted in Web of Science. In 1973–2010, 152 authors published 687 papers in 144 journals in 19 languages abstracted in Scopus. USA authors dominated followed by those from Australia and Canada. Sleep, Int. J. Pediatr. Otorhinolaryngol., Pediatr. Pulmonol. and Pediatrics belonged to ‘core’ journals concerning Web of Science and MEDLINE while Arch. Dis. Childh. and Eur. Respir. J. dominated in Scopus. Nine journals being currently published in 5 countries contained the terms of ‘sleep’ or ‘sleeping’ in their titles. David Gozal, Carole L. Marcus and Christian Guilleminault presented with most publications and citations to them. W.H. Dietz’ paper published in Pediatrics in 1998 received 764 citations. Eighty-four authors from 11 countries participated in 16 scientific events held in 12 countries which were immediately devoted to sleep research. Their 13 articles were cited 170 times in Web of Science. Authors from the University of Louisville, Stanford University, and University of Pennsylvania published most papers on pediatric sleep apnea abstracted in these data-bases. Conclusions: The newly created data-base with the researchers’ names, addresses and publications could be used by scientists from smaller countries for further improvement of their international collaboration. ß 2011 Elsevier Ireland Ltd. All rights reserved.
Keywords: Pediatric sleep apnea International scientific communications Science institutionalization Web of Science MEDLINE Scopus
1. Introduction Obstructive sleep apnea in infancy and childhood is a relatively common disorder characterized by repeated episodes of partial or complete upper airway obstruction during sleep and subsequent disruption of normal ventilation and sleep patterns. Comprehensive assessment of disparities in multiracial populations, access to care, treatment, and utilization of services for pediatric sleepdisordered breathing should be prioritized in health policy research [1]. Data collected from the general population confirm that obstructive sleep disordered breathing in children is related to increased prevalence of central nervous system morbidity including excessive daytime sleepiness and poor academic
* Tel.: +359 52 655572; fax: +359 52 655572; mobile: +359 888897403. E-mail address: [email protected]. 0165-5876/$ – see front matter ß 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2011.11.007
performance [2]. Maladaptive responses to sleep apnea have been recognized in affected children, such as sympathetic nervous system activation, increased oxidative stress, systemic inflammation, endothelial dysfunction, reduced nocturnal baroreflex gain and subclinical abnormalities in cardiac structure and function detectable only by echocardiography [3]. Our recent publications dealing with obstructive sleep apnea prove the socio-medical importance of this pathology for our country, too [4–7]. Problem-oriented scientometric investigations of the internationalization, institutionalization, and interdisciplinarity of science contribute to enhancement of the quality and effectiveness of science forefront [8,9]. Science internationalization includes not only direct research interaction between single scientists from different countries and their teams organized through official contracts or within informal collectives but also a series of the following components [8]:
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M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
(i) continuous creation of new international scientific societies and international associations of national societies, of new international scientific journals and international publishers or publishing houses; (ii) publishing of scientific papers, reviews and book reviews in foreign journals and periodicals; (iii) translation and publishing of monographs by foreign authors; (iv) organization of international scientific forums and participation in them of authors from numerous foreign countries; (v) enrichment of the forms of immediate exchange of scientists from other countries; (vi) unlimited dissemination of new scientific information through modern information-communication technologies; (vii) modernization and automatization of scientific libraries; (viii) introduction of electronic journals and monographs, and (ix) overcoming of the traditional barriers for interpersonal communication between scientists from different countries. As an essential feature of modern interdisciplinary science, institutionalization of research includes the intrinsic features of historically established disciplinary organization of scientific and higher educational structures concordant with enhanced present requirements and already gained social recognition of the topic. It is closely related to research internationalization and represents a component of the mature scientific discipline or subdiscipline [8]. The main objective of this article is to comparatively study some essential peculiarities of dynamic advances in the field of sleep apnea in children and infants by using a complex scientometric method for evaluation of the world publication output and mutually linked aspects of stratification and internationalization of this interdisciplinary research field and thus to contribute to further improvement of the scientific communications in smaller countries. 2. Methods A retrospective and unified problem-oriented search on pediatric sleep apnea was performed in the online-versions of Web of Science (WoS) and MEDLINE (Thomson Reuters, Philadelphia, PA, USA) as well as of Scopus (The Netherlands). Relevant documents were retrieved from Science Citation Index Expanded (SCI Expanded of WoS) (WoS) during the period from January 1985 till December 2010; from MEDLINE – during the period from January 1950 till December 2010, and from Scopus – during the period from January 1970 till December 2010. The following scientometric parameters were analyzed in SCI Expanded: (i) publications – number of abstracted publications (total and per year), languages, types [10] and subject areas of primary publications; (ii) titles and types of scientific events as a whole and those which are immediately devoted to sleep research as well as number of abstracted publications and citations to them; (iii) authors – number of unique names, country belonging as a whole, number of own publications and of citations to some eminent authors; (iv) journals – number of journal titles and of abstracted articles from single journals, thematic and disciplinary profile and ‘core’ journals, (v) scientific institutions – names and country belonging, and (vi) citations – number of citations received by the primary publications in WoS as a whole until August 2011, by 18 most cited publications and by 13 journal articles presented in scientific events immediately devoted to sleep research during the same period. The scientometric analysis of MEDLINE covered the following parameters: (i) publications – number of abstracted publications (total and per year), types, subject categories and specific MESH headings; (ii) authors – unique names and number of their own
publications; (iii) journals – number of journal titles and of abstracted publications from single journals, ‘core’ journals as well as thematic and disciplinary profile. The following scientometric parameters were analyzed in Scopus: (i) publications – number of abstracted publications (total and per year), languages, types and subject areas of primary publications; (ii) authors – unique names and number of their own publications; (iii) journals – number of journal titles and of abstracted articles from single journals, ‘core’ journals as well as thematic and disciplinary profile and (iv) scientific institutions – names and country belonging. The comprehensive study of the constellations of publication output and citation activity patterns elucidated various aspects of the continuous fruitful exchange of ideas, methods, results and suggestions on this increasingly internationalized topic. 3. Results Some of our numerous data concerning certain essential publication output patterns were systematized in 2 figures and 11 tables to illustrate several specific scientometric distributions in this rapidly advancing interdisciplinary field. The dynamic growth of the number of publications in WoS, MEDLINE and Scopus was demonstrated in Fig. 1. It should be added that in MEDLINE, there were 444 papers abstracted between 1972 and 1984 (10.59%) while in Scopus, there were 48 papers abstracted between 1973 and 1984 (6.99%). During the period from 1985 till 2010, more than 8100 authors from 64 countries from all over the world had published 3213 papers abstracted in WoS. USA authors dominated like in any scientometric distributions with a total of 1492 publications abstracted in this data-base (46.41% of all the publications). As shown in Fig. 2, surprisingly, next came the publications by researchers from Australia and Canada. The distributions of most common document types in three data-bases were compared in Table 1. In 626 journals published in 11 languages, there were 2680 abstracted publications while in 256 conference proceedings there were 533 ones. Table 2 shows the variety of languages of publications abstracted in WoS and Scopus. During the period from 1972 till 2010, there were 4192 publications primarily published in 874 journals and abstracted in MEDLINE. On the contrary, in Scopus, during the period from 1973 till 2010, there were only 687 abstracted publications primarily published in 19 languages in 144 journals by 152 unique authors. ‘Core’ journals in three data-bases in the field of pediatric sleep apnea were presented in Tables 3 and 4 while journals containing the terms of ‘sleep’ or ‘sleeping’ in their titles were listed in Table 5. Table 6 systematized most productive authors’ names, countries and numbers of publications abstracted in these data-bases. There were substantial differences in the primary literature coverage by the single data-bases. That was why it seemed necessary to mention that, for example, C.F. Poets presented with 31 abstracted publications in WoS and with 6 ones only in Scopus, A.M. Li did with 12 ones and T.F. Fok did with 11 ones in Scopus, etc. Ten titles of scientific events containing the greatest number of publications abstracted in WoS were demonstrated in Table 7. They represented 10.94% of all the events and contained 32.64% of all the presentations delivered there and subsequently published either in journals, or in conference proceedings. The first four of them could, therefore, be considered ‘core’ scientific events on this narrow topic. The scientific institutions with most publications on pediatric sleep apnea abstracted in WoS and in Scopus were shown in Table 8. Some interesting scientometric peculiarities of 16 scientific events which had been immediately devoted to sleep research were illustrated in Tables 9–11 such as types of events and
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
221
Fig. 1. Annual dynamics of the number of publications in WoS and MEDLINE.
resulting publications (Table 9), country and city distributions (Table 10), and extent of participation and subsequent publication abroad (Table 11). The other seven countries (without authors) not listed in Table 11 were the following: Scotland (with two presentations by authors from Italy and with one presentation by authors from the USA), Spain (with one presentation by authors from Germany), Israel (with one presentation by authors from Belgium), The Netherlands (with two publications by authors from the USA), Ireland (with one publication by authors from Germany), Norway (with one publication by authors from Finland), and Switzerland (with one publication by authors from Japan). Authors from India delivered one presentation in their country and published it there. It should be emphasized that a significant relative share of the presentations (65.22%) and of the publications (79.26%) were in foreign countries and sources, respectively. It testified to the rising research internationalization of this enlarging scientific community.
These events were carried out in 12 countries and 16 cities. There were three cities in France as well as two cities in Canada and Japan. There were 11 countries with 18 cities and 22 institutions of authors. Authors’ total number was 93 and mean number per publication was 4.04. There were 84 unique names as 9 authors presented with two publications each. The authors from the USA worked in 7 institutions located in 5 cities while those from Belgium, Finland, France and Japan worked in two institutions in two cities each. There were 7 publications by one author, 4 – by three authors, 3 – by two, six and seven authors each, 2 – by eight authors, and 1 publication by four and nine authors each. Five of the most productive authors listed in Table 6 such as C.L. Marcus, C. Gaultier, A. Kahn, C.E. Sullivan, and K.A. Waters presented with two publications each in these events while four ones such as D. Gozal, C. Guilleminault, R.T. Brouilltte and J. Groswasser did with one publication each. The articles were published in 10 journals from 6 countries. All the 13 journal articles initially presented in these
Fig. 2. Publication output of some countries in WoS.
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
222
Table 1 Document type distribution in three data-bases. Document types
Original article Review Editorial Letter-to-the-editor Proceedings paper Meeting abstract Controlled clinical trial Meta-analysis Note Other a b
MEDLINEa
WoS n
%
n
%
n
%
2193 313 93 59 340 193 – – 13 –
68.21 9.74 2.89 1.83 10.57 6.00 – – 0.40 –
3947 714 65 159 – – 30 14 – –
94.16 17.01 1.55 3.79 – – 0.71 0.33 – –
464 142 10 20 17 – – – 5 23
68.13 20.85 1.47 2.94 2.50 – – – 0.73 3.38
Covers the period between 1972 and 2010. Covers the period between 1973 and 2010.
Table 2 Language distribution of publications abstracted in two data-bases. Languages
English German French Spanish Italian Portuguese Serbian Czech Japanese Korean Turkish Polish Slovak Dutch Croatian Other (5) a
Scopusb
Scopusa
WoS n
%
n
%
3054 70 48 27 5 3 2 1 2 2 1 – – – – –
94.99 2.18 1.49 0.84 0.15 0.09 0.06 0.03 0.06 0.06 0.03 – – – – –
598 23 20 10 5 4 3 3 1 – 1 4 4 4 3 7
87.81 3.38 2.94 1.47 0.73 0.59 0.44 0.44 0.29 – 0.15 0.59 0.59 0.59 0.44 1.03
Covers the period between 1973 and 2010.
events were meanwhile cited and received a total of 170 citations in WoS. During the period from January 1985 till August 2011, a total of 2665 publications abstracted in WoS in 1985–2010, received a total of 53,345 citations. Of them, 31,264 citations were not author’s self-citations. The average number of citations per year was 1975.74. There were a total of 21,754 citing articles. Hirsch-index (h-index) [11] of this narrow topic was relatively high – of 91. A
total of 18 papers received more than 200 citations each. The mostcited article published by W.H. Dietz in Pediatrics in 1998 had already received a total of 764 citations. Some most productive authors were highly cited, too. C.L. Marcus presented with 3 of these 18 most-cited papers (cited 919 times), D. Gozal did with two papers (cited 603 times) while R.T. Brouillette, S.D. Ward, J.L. Carroll, C. Guilleminault and C.L. Rosen did with one paper each. It should be added that until August 2011, a total of 122 David Gozal’s publications on pediatric sleep apnea received 4064 citations by 1172 citing articles. Of these citations, 3143 or 77.34% were not author’s self-citations. The average number of citations per item was 25.40 but per year it was 225.78. His h-index was 35. During the same period, a total of 71 Carole L. Marcus’ publications on pediatric sleep apnea received 3060 citations by 1564 citing articles. Of these citations, 2759 or 90.14% were not author’s self-citations. The average number of citations per item was 36.87 but per year it was 153.00. His h-index is 28. In WoS, the following subject areas of publications prevailed: pediatrics (with 1039 papers or 32.32% of a total of 3213 papers), clinical neurology (with 606 papers or 18.85%), respiratory system (with 499 papers or 15.52%), otorhinolaryngology (with 476 papers or 14.80%), neurosciences (with 438 papers or 13.62%), surgery (with 269 papers or 8.37%), and physiology (with 156 papers or 4.85%). In Scopus, however, the subject areas were not so detailed. To medicine, 638 or 92.87% of a total of 687 publications had been assigned. Next came neurosciences (with 51 papers or 7.42%), dentistry (with 26 papers or 3.78%), pharmacology, toxicology and pharmaceutics (with 18 papers or 2.62%), psychology (with 14 papers or 2.04%), health professions (with 13 papers or 1.89%), engineering (with 10 papers or 1.45%), etc. In
Table 3 ‘Core’ journals in WoS and in MEDLINE in the field of pediatric sleep apnea. No.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. a
Journal title
Sleep Int. J. Pediatr. Otorhinolaryngol. Pediatr. Pulmonol. Pediatrics Am. J. Respir. Crit. Care Med. Chest J. Appl. Physiol. J. Pediatr. Arch. Otolaryngol. Head Neck Surg. Otolaryngol. Head Neck Surg. Sleep Med. Pediatr. Res. Laryngoscope
Covers the period between 1972 and 2010.
Country code
US IE US US US US US US US GB NL US US
MEDLINEa
WoS n
%
n
%
254 146 123 122 94 87 77 74 61 59 59 52 50
7.90 4.54 3.82 3.79 2.92 2.71 2.39 2.30 1.90 1.83 1.83 1.62 1.55
144 154 120 187 89 89 62 99 62 58 61 48 57
3.43 3.67 2.86 4.45 2.12 2.12 1.48 2.36 1.48 1.38 1.45 1.14 1.36
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226 Table 4 ‘Core’ journals in Scopusa in the field of pediatric sleep apnea.
223
Table 6 Most productive authors and their countries in three data-bases.
No.
Journal title
Country code
n
%
Author
Country code
WoS
MEDLINEa
Scopusb
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Arch. Dis. Childh. Eur. Respir. J. J. Pediatr. Child Health Paediatr. Respir. Rev. J. Laryngol. Otol. Int. J. Pediatr. Otorhinolaryngol. Eur. J. Pediatr. Int. J. Pediatr. Thorax Lancet J. Sleep Res. Clin. Otolaryngol. Allied Sci. Eur. J. Orthod.
US CH AU GB GB IE DE EG GB GB GB GB GB
38 29 19 19 19 17 16 15 15 14 13 10 9
5.58 4.26 2.79 2.79 2.79 2.50 2.35 2.20 2.20 2.05 1.91 1.47 1.32
David Gozal Carole L. Marcus Christian Guilleminault Leila Kheirandish-Gozal Andre Kahn Jose Groswasser Claude Gaultier Robert T. Brouillette Carol L. Rosen Louise M. O’Brien Thomas G. Keens Athanasios G. Kaditis S.L.D. Ward Konstantinos Gourgoulianis Daniel K. Ng Ron B. Mitchell Raouf S. Amin C.E. Hunt C.E. Sullivan Chung-Hong Chan Karen A. Waters Ka-Li Kwok
US US US US BE BE FR CA US US US GR US GR CN US US US AU CN AU CN
158 83 65 63 45 38 34 32 33 31 26 25 26 25 21 24 31 12 19 18 30 15
170 83 112 64 77 46 54 41 31 31 35 24 27 27 29 24 21 30 23 26 31 21
7 – 5 3 4 – 4 3 – 2 – – – – 10 – – – 5 2 7 6
a
Covers the period between 1973 and 2010.
MEDLINE, numerous subject categories had been assigned to one and the same publication. Similarly to WoS, the majority of the publications belonged simultaneously to the three main categories, i.e. of pediatrics (94.61%), respiratory system (91.99%), and neurosciences and neurology (90.73%). Surprisingly, next came the category of medical laboratory technology (with 1356 papers or 32.31% of a total of 4192 papers) followed by behavioural sciences (with 1226 papers or 29.21%) and psychology (with 1201 papers or 28.61%, respectively), surgery (with 1121 papers or 26.71%), otorhinolaryngology (with 1050 papers or 25.02%), cardiovascular system and cardiology (with 811 papers or 19.32%), dentistry, oral surgery and medicine (with 700 papers or 16.68%), physiology (with 670 papers or 15.96%), etc. This considerable variety of the subjects argued convincingly of the interdisciplinary nature of the narrow topic of pediatric sleep apnea. This statement was valid for the thematic and disciplinary belonging of the journals and scientific meetings, too. A detailed scientometric characteristic of the presence in these data-bases of four significant problems closely related to pediatric sleep apnea research, i.e. of adenotonsillectomy, obesity, noninvasive ventilation (or continuous positive airway pressure), and neurocognition is demonstrated in Tables 12–14. There are remarkable differences between these topics concerning the publication output and citation features. 4. Discussion The present results are similar to our previous work [12]. They convincingly demonstrate the rapid science advancement in the socially significant interdisciplinary field of obstructive sleep apnea in infancy and childhood. The complex analysis of the mutually linked aspects of internationalization and institutionalization by
a b
Covers the period between 1972 and 2010. Covers the period between 1973 and 2010.
means of properly selected constellations of scientometric parameters reveals the dynamic stratification of the forefront of this narrow topic, on the one hand, and the diversification of scientific communication channels worldwide, especially in the new millennium, on the other hand. Recent science expansion stresses, indeed. The relatively high number of review articles indicates a considerable degree of maturation of the topic. It is manifested by the large amount of specialized international scientific meetings where novelties are regularly presented, discussed and, fortunately, subsequently published in specialized proceedings and journals. The comparative assessment of WoS, MEDLINE and Scopus illustrates not only certain attractive advantages but also some disadvantages and pitfalls of these information-retrieval and information-storage systems for end users. There exist considerable differences between the three data-bases concerning the number of papers abstracted from one and the same journal preliminarily published by one and the same author during one and the same period. Besides they provide a variety of opportunities for automated problem-oriented scientometric analyses illustrated in Tables 12–14. Further improvements of the coverage scope of the primary scientific literature along with uninterrupted enrichment of processing capacities and steady refinement of indexing algorithms are needed.
Table 5 Journals containing the term of ‘sleep’ in their titles in three data-bases. Journal/country code of publication
Sleep (US) Sleep Medicine (NL) Journal of Sleep Research (GB) Sleep Medicine Reviews (GB) Sleep and Breathing (DE) Journal of Clinical Sleep Medicine (US) Somnologie (DE) Sleep and Hypnosis (TR) Waking and Sleeping (DE) a b
Covers the period between 1972 and 2010. Covers the period between 1973 and 2010.
MEDLINEa
WoS
Scopusb
n
%
n
%
n
%
254 59 35 28 17 – – – –
7.90 1.83 1.09 0.87 0.53 – – – –
144 61 26 24 23 31 – – –
3.43 1.45 0.62 0.57 0.55 0.74 – – –
– 2 13 6 2 – 5 1 1
– 0.03 1.91 0.09 0.03 – 0.07 0.01 0.01
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
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Table 7 Conference proceedings with most publications abstracted in WoS. Conference title
No.
Number of events
7. 8. 9. 10.
Annual Meeting of the Associated Professional Sleep Societies Annual Meeting of the American Society of Pediatric Otolaryngology Annual International Conference of the IEEE – Engineering In Medicine and Biology Society Annual Meeting of the American Academy of Otolaryngology, Head and Neck Surgery International Congress of Pediatric Otorhinolaryngology Research Colloquium on Control of Breathing During Development: Apnea of the Newborn and in Sudden Infant Death Syndrome International Congress on Pediatric Pulmonology Congress of the European Sleep Research Society Congress of the World Association of Sleep Medicine Symposium on Diagnosis and Treatment of Sleep Breathing Disorders
Total
28
1. 2. 3. 4. 5. 6.
n
%
7 6 4 4 2 1
91 21 19 14 8 5
17.07 3.94 3.56 2.63 1.50 0.94
1 1 1 1
4 3 3 3
0.75 0.56 0.56 0.56
174
Table 8 Most productive scientific institutions in WoS and in Scopus.
32.64
Table 9 Publications in scientific events immediately devoted to sleep research.
Institution
Country code
WoS
Scopusa
University of Louisville Stanford University University of Pennsylvania Case Western Reserve University University of Sydney Harvard University Johns Hopkins University University of Michigan McGill University Free University of Brussels University of South California Children’s Hospital of Philadelphia University of Cincinnati University of Chicago Universita degli Study di Roma La Sapienza University of Arizona University of Washington Kwong Wah Hospital Chinese University of Hong Kong Children’s Hospital at Westmead Monash University Monash Medical Center
US US US US AU US US US CA BE US US US US IT
151 86 71 64 63 63 61 59 57 50 49 45 45 44 41
6 – – – 29 – – – – – – – – – 6
US US CN CN AU AU AU
34 33 24 28 17 25 16
– – 10 7 21 5 6
a
Publications
Covers the period between 1973 and 2010.
In the recent scientometric literature, there is a permanent interest in research internationalization [13,14]. Some probable indicators of research internationalization to serve policy-makers, research funders and research-performing organizations were suggested [15]. The analysis of the international research profiles of Europe’s top 10 largest multinational pharmaceutical companies based on publication counts and author address information shows that international research activity of European industry is significantly more oriented towards the US science base than vice versa [16].
n
Type
Publications Journal articles
Congresses Symposia Conferences Meetings Forum Workshop Total
Proceeding papers
Meeting abstracts
Total
7 4 2 1 1 1
3 7 1 1 1 –
5 – 1 – – 1
3 – – – – –
11 7 2 1 1 1
16
13
7
3
23
International collaboration is closely related to the visibility of science in some countries on the international scientific market [17,18], e.g. as examined by means of an international publication ratio [19]. The interuniversity, interregional and international collaboration networks generated by Spanish universities were studied by means of social network visualization techniques [20]. It was demonstrated that the international collaboration was implemented mainly with authors from European Union, North and Latin America. In The Netherlands, in 1988–2004, there is a high share of international research collaborations as collaborating within national research systems helps academia, firms and governmental organizations to overcome differences in norms, values and incentives [21]. Science institutionalization patterns are comprehensively studied like in cell biology [8], adipobiology [22], adipobiology and hypertension-related memory [23], nanotechnology [24], and memory research [9]. The successful creation of international joint laboratories by the French Centre National de la Recherche Scientifique and the German Max-Planck-Gesellschaft is an example of the institutionalization of the dynamics of previously selforganised international collaborations [25]. Such modern models
Table 10 Country and city distributions of events on sleep research. Countries
Countries Countries Countries Countries Countries Countries
Total
with cities of scientific events of authors with publications with cities of authors with institutions with cities of institutions with journals
12 11 11 11 11 6
Cities/authors/institutions/journals With 1
With 2
With 3
With 5
With 6
With 7
9 4 7 5 6 3
2 5 3 4 4 2
1 1 – 1 – 1
– – 1 – – –
– 1 – – 1 –
– – – 1 – –
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Table 11 Number of presentations in events on sleep research and of their publications in the own country and abroad. Country codes of authors
Country of presentation/country of publication US
FR
IT
BE
FI
JP
AU
DE
CA
Other (7)
US (6) FR (3) IT (2) BE (2) FI (2) JP (2) AU (2) DE (1) CA (1) IN (1) CN (1)
1/3 0/1 0/2 0/1 – – 0/2 – 1/1 – –
2/1 2/1 – – – – 1/0 – – – –
– 0/1 – 1/0 0/1 – – – – – 0/1
– – – – – – – – – – –
– – – – 1/0 – – – – – –
– – – – – 2/0 – – – – –
– – – – – 0/1 1/0 – – – –
– 1/0 – 0/1 1/0 – – – – – 1/0
2/0 – – – – – – – – – –
1/2 – 2/0 1/0 0/1 0/1 – 1/1
Total (23)
2/10
5/2
1/3
0/0
1/0
2/0
1/1
3/1
2/0
6/6
1/1 –
Digits in brackets indicate the total number of published presentations by the authors of the corresponding country.
Table 12 Scientometric patterns of publications abstracted in WoS on four narrow topics related to pediatric sleep apnea. Parameter
Adenotonsillectomy
Obesity
Non-invasive ventilation
Neurocognition
Publications Countries of authors Journals Articles Reviews Conferences Conference papers/abstracts Editorials Letters Languages Year span Leading scientist Leading journal Leading institution Times cited without self-citation Citing articles Average citations per item Average citations per year h-Index
694 39 165 565 63 64 114 18 19 5 1985–2010 D. Gozal Int. J. Ped. Orl. Univ. Louisville 8139 3932 18.43 473.81 53
370 41 158 274 68 39 45 13 2 7 1991–2010 D. Gozal Sleep Univ. Louisville 9086 6331 28.13 520.40 51
164 32 86 140 22 13 14 1
84 18 42 61 18 5 5 2 – 3 1995–2010 D. Gozal Pediatrics Univ. Louisville 2237 1209 30.44 170.47 24
6 1991–2010 C. Guilleminault Sleep Stanford Univ. 2262 1792 15.49 127.05 27
Table 13 Scientometric patterns of publications abstracted in MEDLINE on four narrow topics related to pediatric sleep apnea. Parameter
Adenotonsillectomy
Obesity
Non-invasive ventilation
Neurocognition
Publications Journals Articles Reviews Editorial Letter Comparative study Clinical trial Controlled clin. trial Meta-analysis Multi center study Comment Randomized trial Year span Leading scientist
798 239 758 121 6 31 86 38 11 5 16 28 30 1976–2010 D. Gozal
447 211 419 129 6 15 34 4 3
157 95 155 31 1 1 8 6 2
87 49 85 32 2
5 21 2 1972–2010 D. Gozal
3
7 2 1 1 1
4 1983–2010 C.E. Sullivan
1995–2010 D. Gozal
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226
Table 14 Scientometric patterns of publications abstracted in Scopus on four narrow topics related to pediatric sleep apnea. Parameter
Adenotonsillectomy
Obesity
Non-invasive ventilation
Neurocognition
Publications Countries of authors Journals Articles Reviews Conference papers Editorial Letter Languages Year span Leading scientist Leading journal Leading institution
315 29 126 205 80 10 6 9 10 1987–2010 D. Gozal Int. J. Ped. Orl. Univ. Louisville
169 23 101 95 63 5 3
19 7 15 11 4
40 11 31 20 19
1
1
8 1994–2010 D. Gozal Ped. Pulmonol. Cincinnati Hosp.
4 1983–2010 D. Gozal Resp. Care Univ. Calgari
7 2000–2010 D. Gozal Sleep Med. Rev. Univ. Louisville
should be widely popularized among scientists themselves, science managers and policy makers in sleep apnea research, too. Obviously, modern science becomes more and more interdisciplinary [26]. Our results provide convincing evidence that respiratory sleep disorders present with increasing interdisciplinarity. Besides they promote further international research of patient’s individual health-related quality of life, e.g., by a validated quality of life survey of pediatric obstructive sleep apnea [27]. It could be concluded that this scientometric investigation has created a comprehensive problem-oriented data-base containing systematized files with the researchers’ names, addresses and publications designed mainly for the scientists from smaller countries. Its effective usage could contribute to the further improvement of their scientific communications and international collaboration with eminent colleagues from all over the world. Conflict of interest Herewith the author declares no conflict of interest at all. Funding There is no financial support for the present study. References [1] E.F. Boss, D.F. Smith, S.L. Ishman, Racial/ethnic and socioeconomic disparities in the diagnosis and treatment of sleep-disordered breathing in children, Int. J. Pediatr. Otorhinolaryngol. 75 (2011) 299–307. [2] J.L. Goodwin, K.L. Kaemingk, R.F. Fregosi, G.M. Rosen, W.J. Morgan, D.L. Sherrill, et al., Clinical outcomes associated with sleep-disordered breathing in Caucasian and Hispanic children – the Tucson Children’s Assessment of Sleep Apnea study (TuCASA), Sleep 26 (2003) 587–591. [3] L. Kheirandish-Gozal, R. Bhattacharjee, J. Kim, H.B. Clair, D. Gozal, Endothelial progenitor cells and vascular dysfunction in children with obstructive sleep apnea, Am. J. Respir. Crit. Care Med. 182 (2010) 92–97. [4] M. Milkov, Z. Tonchev, Surgical treatments of sleep-determined respiratory disorders in a historical aspect, Otorinolaringol. Mezhdunar. Byul. (Varna) 4 (2) (2008) 26–31 (in Bulgarian). [5] P. Nedev, G. Boyadzhiev, M. Milkov, Types of interventions for treatment of snoring and obstructive sleep apnea, Otorinolaringol. Mezhdunar. Byul. (Varna) 4 (2) (2008) 47–51 (in Bulgarian). [6] M. Milkov, Diagnosis of sleep disorders, Otorinolaringol. Mezhdunar. Byul. (Varna) 5 (4) (2009) 31–35 (in Bulgarian).
[7] M. Milkov, Clinically determined respiratory sleep disorders, Otorinolaringol. Mezhdunar. Byul. (Varna) 5 (4) (2009) 37–39 (in Bulgarian). [8] D.T. Tomov, The unity of interdisciplinarity, institutionalization and internationalization of science: reflections from/on cell biology, Biomed. Rev. 12 (2001) 41– 55. [9] D.T. Tomov, Institutionalization of interdisciplinary research under the conditions of internationalization (scientometric and historiographic aspects of the problem of ‘memory’), DSc thesis in Social Studies of Science, Centre for Science Studies and History of Science, Sofia, 2010 (in Bulgarian). [10] D.T. Tomov, H.G. Mutafov, Dynamic stratification of document-type distributions in interdisciplinary biomedical research, Scr. Period. (Sofia) 7 (Suppl.) (2004) 12– 18. [11] J.E. Hirsch, An index to quantify an individual’s scientific research output, Proc. Natl. Acad. Sci. U.S.A. 102 (2005) 16569–16572. [12] M. Milkov, D. Tomov, Institutionalization of research in the field of sleep apnea in infancy and childhood, in: Congress of the International Pediatric Sleep Association. Joint Meeting with Pediatric Sleep Medicine Conference, Rome, 3–5 December, 2010, Poster No. 128, 57. [13] G. Abramo, C.A. D’Angelo, M. Solazzi, The relationship between scientists’ research performance and the degree of internationalization of their research, Scientometrics 86 (2011) 629–643. [14] M. Zitt, S. Ramanana-Rahary, E. Bassecoulard, Correcting glasses help fair comparisons in international science landscape: Country indicators as a function of ISI database delineation, Scientometrics 56 (2003) 259–282. [15] J. Edler, K. Flanagan, Indicator needs for the internationalisation of science policies, Res. Eval. 20 (2011) 7–17. [16] R.J.W. Tijssen, Internationalisation of pharmaceutical R&D: how globalised are Europe’s largest multinational companies? Technol. Anal. Strateg. Manag. 21 (2009) 859–879. [17] W. Gla¨nzel, A. Schubert, Domesticity and internationality in co-authorship, references and citations, Scientometrics 65 (2005) 323–342. [18] D. Tomov, International visibility of Bulgarian memory research, Scr. Sci. Med. (Varna) 36 (2004) 65–69. [19] P. Leite, R. Mugnaini, J. Leta, A new indicator for international visibility: exploring Brazilian scientific community, Scientometrics 88 (2011) 311–319. [20] C. Olmeda-Gomez, A. Perianes-Rodriguez, M.A. Ovalle-Perandones, V.P. GuerreroBote, F.D. Anegon, Visualization of scientific co-authorship in Spanish universities – from regionalization to internationalization, ASLIB Proc. 61 (2009) 83–100. [21] R. Ponds, The limits to internationalization of scientific research ollaboration, J. Technol. Transfer 34 (2009) 76–94. [22] D.T. Tomov, Adipobiology: a scientometric view to its increasing significance, Biomed. Rev. 17 (2006) 113–118. [23] D. Tomov, A. Penev, Adipobiology and hypertension-related memory: a scientometric approach to publication output, Heart–Lung (Varna) 12 (1) (2006) 35–45. [24] J. Schummer, The global institutionalization of nanotechnology research: a bibliometric approach to the assessment of science policy, Scientometrics 70 (2007) 669–692. [25] K. Jonkers, L. Cruz-Castro, The internationalisation of public sector research through international joint laboratories, Sci. Publ. Policy 37 (2010) 559–570. [26] A.L. Porter, I. Rafols, Is science becoming more interdisciplinary? Measuring and mapping six research fields over time, Scientometrics 81 (2009) 719–745. [27] E. Ericsson, I. Lundeborg, E. Hultcrantz, Child behavior and quality of life before and after tonsillotomy versus tonsillectomy, Int. J. Pediatr. Otorhinolaryngol. 73 (September (9)) (2009) 1254–1262.
Contents lists available at SciVerse ScienceDirect
International Journal of Pediatric Otorhinolaryngology journal homepage: www.elsevier.com/locate/ijporl
Internationalization of pediatric sleep apnea research Mario Milkov * St. Petka Eye and Ear Clinic of Varna, 40 Slivnitsa Blvd, BG-9002 Varna, Bulgaria
A R T I C L E I N F O
A B S T R A C T
Article history: Received 14 September 2011 Received in revised form 7 November 2011 Accepted 8 November 2011 Available online 14 December 2011
Objective: Recently, the socio-medical importance of obstructive sleep apnea in infancy and childhood increases worldwide. The present investigation aims at analyzing the dynamic science internationalization in this narrow field as reflected in three data-bases and at outlining the most significant scientists, institutions and primary information sources. Methods: A scientometric study of data from a retrospective problem-oriented search on pediatric sleep apnea in three data-bases such as Web of Science, MEDLINE and Scopus was carried out. A set of parameters of publication output and citations was followed-up. Several scientometric distributions were created and enabled the identification of some essential peculiarities of the international scientific communications. Results: There was a steady world publication output increase. In 1972–2010, 4192 publications from 874 journals were abstracted in MEDLINE. In 1985–2010, more than 8100 authors from 64 countries published 3213 papers in 626 journals and 256 conference proceedings abstracted in Web of Science. In 1973–2010, 152 authors published 687 papers in 144 journals in 19 languages abstracted in Scopus. USA authors dominated followed by those from Australia and Canada. Sleep, Int. J. Pediatr. Otorhinolaryngol., Pediatr. Pulmonol. and Pediatrics belonged to ‘core’ journals concerning Web of Science and MEDLINE while Arch. Dis. Childh. and Eur. Respir. J. dominated in Scopus. Nine journals being currently published in 5 countries contained the terms of ‘sleep’ or ‘sleeping’ in their titles. David Gozal, Carole L. Marcus and Christian Guilleminault presented with most publications and citations to them. W.H. Dietz’ paper published in Pediatrics in 1998 received 764 citations. Eighty-four authors from 11 countries participated in 16 scientific events held in 12 countries which were immediately devoted to sleep research. Their 13 articles were cited 170 times in Web of Science. Authors from the University of Louisville, Stanford University, and University of Pennsylvania published most papers on pediatric sleep apnea abstracted in these data-bases. Conclusions: The newly created data-base with the researchers’ names, addresses and publications could be used by scientists from smaller countries for further improvement of their international collaboration. ß 2011 Elsevier Ireland Ltd. All rights reserved.
Keywords: Pediatric sleep apnea International scientific communications Science institutionalization Web of Science MEDLINE Scopus
1. Introduction Obstructive sleep apnea in infancy and childhood is a relatively common disorder characterized by repeated episodes of partial or complete upper airway obstruction during sleep and subsequent disruption of normal ventilation and sleep patterns. Comprehensive assessment of disparities in multiracial populations, access to care, treatment, and utilization of services for pediatric sleepdisordered breathing should be prioritized in health policy research [1]. Data collected from the general population confirm that obstructive sleep disordered breathing in children is related to increased prevalence of central nervous system morbidity including excessive daytime sleepiness and poor academic
* Tel.: +359 52 655572; fax: +359 52 655572; mobile: +359 888897403. E-mail address: [email protected]. 0165-5876/$ – see front matter ß 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijporl.2011.11.007
performance [2]. Maladaptive responses to sleep apnea have been recognized in affected children, such as sympathetic nervous system activation, increased oxidative stress, systemic inflammation, endothelial dysfunction, reduced nocturnal baroreflex gain and subclinical abnormalities in cardiac structure and function detectable only by echocardiography [3]. Our recent publications dealing with obstructive sleep apnea prove the socio-medical importance of this pathology for our country, too [4–7]. Problem-oriented scientometric investigations of the internationalization, institutionalization, and interdisciplinarity of science contribute to enhancement of the quality and effectiveness of science forefront [8,9]. Science internationalization includes not only direct research interaction between single scientists from different countries and their teams organized through official contracts or within informal collectives but also a series of the following components [8]:
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M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
(i) continuous creation of new international scientific societies and international associations of national societies, of new international scientific journals and international publishers or publishing houses; (ii) publishing of scientific papers, reviews and book reviews in foreign journals and periodicals; (iii) translation and publishing of monographs by foreign authors; (iv) organization of international scientific forums and participation in them of authors from numerous foreign countries; (v) enrichment of the forms of immediate exchange of scientists from other countries; (vi) unlimited dissemination of new scientific information through modern information-communication technologies; (vii) modernization and automatization of scientific libraries; (viii) introduction of electronic journals and monographs, and (ix) overcoming of the traditional barriers for interpersonal communication between scientists from different countries. As an essential feature of modern interdisciplinary science, institutionalization of research includes the intrinsic features of historically established disciplinary organization of scientific and higher educational structures concordant with enhanced present requirements and already gained social recognition of the topic. It is closely related to research internationalization and represents a component of the mature scientific discipline or subdiscipline [8]. The main objective of this article is to comparatively study some essential peculiarities of dynamic advances in the field of sleep apnea in children and infants by using a complex scientometric method for evaluation of the world publication output and mutually linked aspects of stratification and internationalization of this interdisciplinary research field and thus to contribute to further improvement of the scientific communications in smaller countries. 2. Methods A retrospective and unified problem-oriented search on pediatric sleep apnea was performed in the online-versions of Web of Science (WoS) and MEDLINE (Thomson Reuters, Philadelphia, PA, USA) as well as of Scopus (The Netherlands). Relevant documents were retrieved from Science Citation Index Expanded (SCI Expanded of WoS) (WoS) during the period from January 1985 till December 2010; from MEDLINE – during the period from January 1950 till December 2010, and from Scopus – during the period from January 1970 till December 2010. The following scientometric parameters were analyzed in SCI Expanded: (i) publications – number of abstracted publications (total and per year), languages, types [10] and subject areas of primary publications; (ii) titles and types of scientific events as a whole and those which are immediately devoted to sleep research as well as number of abstracted publications and citations to them; (iii) authors – number of unique names, country belonging as a whole, number of own publications and of citations to some eminent authors; (iv) journals – number of journal titles and of abstracted articles from single journals, thematic and disciplinary profile and ‘core’ journals, (v) scientific institutions – names and country belonging, and (vi) citations – number of citations received by the primary publications in WoS as a whole until August 2011, by 18 most cited publications and by 13 journal articles presented in scientific events immediately devoted to sleep research during the same period. The scientometric analysis of MEDLINE covered the following parameters: (i) publications – number of abstracted publications (total and per year), types, subject categories and specific MESH headings; (ii) authors – unique names and number of their own
publications; (iii) journals – number of journal titles and of abstracted publications from single journals, ‘core’ journals as well as thematic and disciplinary profile. The following scientometric parameters were analyzed in Scopus: (i) publications – number of abstracted publications (total and per year), languages, types and subject areas of primary publications; (ii) authors – unique names and number of their own publications; (iii) journals – number of journal titles and of abstracted articles from single journals, ‘core’ journals as well as thematic and disciplinary profile and (iv) scientific institutions – names and country belonging. The comprehensive study of the constellations of publication output and citation activity patterns elucidated various aspects of the continuous fruitful exchange of ideas, methods, results and suggestions on this increasingly internationalized topic. 3. Results Some of our numerous data concerning certain essential publication output patterns were systematized in 2 figures and 11 tables to illustrate several specific scientometric distributions in this rapidly advancing interdisciplinary field. The dynamic growth of the number of publications in WoS, MEDLINE and Scopus was demonstrated in Fig. 1. It should be added that in MEDLINE, there were 444 papers abstracted between 1972 and 1984 (10.59%) while in Scopus, there were 48 papers abstracted between 1973 and 1984 (6.99%). During the period from 1985 till 2010, more than 8100 authors from 64 countries from all over the world had published 3213 papers abstracted in WoS. USA authors dominated like in any scientometric distributions with a total of 1492 publications abstracted in this data-base (46.41% of all the publications). As shown in Fig. 2, surprisingly, next came the publications by researchers from Australia and Canada. The distributions of most common document types in three data-bases were compared in Table 1. In 626 journals published in 11 languages, there were 2680 abstracted publications while in 256 conference proceedings there were 533 ones. Table 2 shows the variety of languages of publications abstracted in WoS and Scopus. During the period from 1972 till 2010, there were 4192 publications primarily published in 874 journals and abstracted in MEDLINE. On the contrary, in Scopus, during the period from 1973 till 2010, there were only 687 abstracted publications primarily published in 19 languages in 144 journals by 152 unique authors. ‘Core’ journals in three data-bases in the field of pediatric sleep apnea were presented in Tables 3 and 4 while journals containing the terms of ‘sleep’ or ‘sleeping’ in their titles were listed in Table 5. Table 6 systematized most productive authors’ names, countries and numbers of publications abstracted in these data-bases. There were substantial differences in the primary literature coverage by the single data-bases. That was why it seemed necessary to mention that, for example, C.F. Poets presented with 31 abstracted publications in WoS and with 6 ones only in Scopus, A.M. Li did with 12 ones and T.F. Fok did with 11 ones in Scopus, etc. Ten titles of scientific events containing the greatest number of publications abstracted in WoS were demonstrated in Table 7. They represented 10.94% of all the events and contained 32.64% of all the presentations delivered there and subsequently published either in journals, or in conference proceedings. The first four of them could, therefore, be considered ‘core’ scientific events on this narrow topic. The scientific institutions with most publications on pediatric sleep apnea abstracted in WoS and in Scopus were shown in Table 8. Some interesting scientometric peculiarities of 16 scientific events which had been immediately devoted to sleep research were illustrated in Tables 9–11 such as types of events and
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
221
Fig. 1. Annual dynamics of the number of publications in WoS and MEDLINE.
resulting publications (Table 9), country and city distributions (Table 10), and extent of participation and subsequent publication abroad (Table 11). The other seven countries (without authors) not listed in Table 11 were the following: Scotland (with two presentations by authors from Italy and with one presentation by authors from the USA), Spain (with one presentation by authors from Germany), Israel (with one presentation by authors from Belgium), The Netherlands (with two publications by authors from the USA), Ireland (with one publication by authors from Germany), Norway (with one publication by authors from Finland), and Switzerland (with one publication by authors from Japan). Authors from India delivered one presentation in their country and published it there. It should be emphasized that a significant relative share of the presentations (65.22%) and of the publications (79.26%) were in foreign countries and sources, respectively. It testified to the rising research internationalization of this enlarging scientific community.
These events were carried out in 12 countries and 16 cities. There were three cities in France as well as two cities in Canada and Japan. There were 11 countries with 18 cities and 22 institutions of authors. Authors’ total number was 93 and mean number per publication was 4.04. There were 84 unique names as 9 authors presented with two publications each. The authors from the USA worked in 7 institutions located in 5 cities while those from Belgium, Finland, France and Japan worked in two institutions in two cities each. There were 7 publications by one author, 4 – by three authors, 3 – by two, six and seven authors each, 2 – by eight authors, and 1 publication by four and nine authors each. Five of the most productive authors listed in Table 6 such as C.L. Marcus, C. Gaultier, A. Kahn, C.E. Sullivan, and K.A. Waters presented with two publications each in these events while four ones such as D. Gozal, C. Guilleminault, R.T. Brouilltte and J. Groswasser did with one publication each. The articles were published in 10 journals from 6 countries. All the 13 journal articles initially presented in these
Fig. 2. Publication output of some countries in WoS.
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
222
Table 1 Document type distribution in three data-bases. Document types
Original article Review Editorial Letter-to-the-editor Proceedings paper Meeting abstract Controlled clinical trial Meta-analysis Note Other a b
MEDLINEa
WoS n
%
n
%
n
%
2193 313 93 59 340 193 – – 13 –
68.21 9.74 2.89 1.83 10.57 6.00 – – 0.40 –
3947 714 65 159 – – 30 14 – –
94.16 17.01 1.55 3.79 – – 0.71 0.33 – –
464 142 10 20 17 – – – 5 23
68.13 20.85 1.47 2.94 2.50 – – – 0.73 3.38
Covers the period between 1972 and 2010. Covers the period between 1973 and 2010.
Table 2 Language distribution of publications abstracted in two data-bases. Languages
English German French Spanish Italian Portuguese Serbian Czech Japanese Korean Turkish Polish Slovak Dutch Croatian Other (5) a
Scopusb
Scopusa
WoS n
%
n
%
3054 70 48 27 5 3 2 1 2 2 1 – – – – –
94.99 2.18 1.49 0.84 0.15 0.09 0.06 0.03 0.06 0.06 0.03 – – – – –
598 23 20 10 5 4 3 3 1 – 1 4 4 4 3 7
87.81 3.38 2.94 1.47 0.73 0.59 0.44 0.44 0.29 – 0.15 0.59 0.59 0.59 0.44 1.03
Covers the period between 1973 and 2010.
events were meanwhile cited and received a total of 170 citations in WoS. During the period from January 1985 till August 2011, a total of 2665 publications abstracted in WoS in 1985–2010, received a total of 53,345 citations. Of them, 31,264 citations were not author’s self-citations. The average number of citations per year was 1975.74. There were a total of 21,754 citing articles. Hirsch-index (h-index) [11] of this narrow topic was relatively high – of 91. A
total of 18 papers received more than 200 citations each. The mostcited article published by W.H. Dietz in Pediatrics in 1998 had already received a total of 764 citations. Some most productive authors were highly cited, too. C.L. Marcus presented with 3 of these 18 most-cited papers (cited 919 times), D. Gozal did with two papers (cited 603 times) while R.T. Brouillette, S.D. Ward, J.L. Carroll, C. Guilleminault and C.L. Rosen did with one paper each. It should be added that until August 2011, a total of 122 David Gozal’s publications on pediatric sleep apnea received 4064 citations by 1172 citing articles. Of these citations, 3143 or 77.34% were not author’s self-citations. The average number of citations per item was 25.40 but per year it was 225.78. His h-index was 35. During the same period, a total of 71 Carole L. Marcus’ publications on pediatric sleep apnea received 3060 citations by 1564 citing articles. Of these citations, 2759 or 90.14% were not author’s self-citations. The average number of citations per item was 36.87 but per year it was 153.00. His h-index is 28. In WoS, the following subject areas of publications prevailed: pediatrics (with 1039 papers or 32.32% of a total of 3213 papers), clinical neurology (with 606 papers or 18.85%), respiratory system (with 499 papers or 15.52%), otorhinolaryngology (with 476 papers or 14.80%), neurosciences (with 438 papers or 13.62%), surgery (with 269 papers or 8.37%), and physiology (with 156 papers or 4.85%). In Scopus, however, the subject areas were not so detailed. To medicine, 638 or 92.87% of a total of 687 publications had been assigned. Next came neurosciences (with 51 papers or 7.42%), dentistry (with 26 papers or 3.78%), pharmacology, toxicology and pharmaceutics (with 18 papers or 2.62%), psychology (with 14 papers or 2.04%), health professions (with 13 papers or 1.89%), engineering (with 10 papers or 1.45%), etc. In
Table 3 ‘Core’ journals in WoS and in MEDLINE in the field of pediatric sleep apnea. No.
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. a
Journal title
Sleep Int. J. Pediatr. Otorhinolaryngol. Pediatr. Pulmonol. Pediatrics Am. J. Respir. Crit. Care Med. Chest J. Appl. Physiol. J. Pediatr. Arch. Otolaryngol. Head Neck Surg. Otolaryngol. Head Neck Surg. Sleep Med. Pediatr. Res. Laryngoscope
Covers the period between 1972 and 2010.
Country code
US IE US US US US US US US GB NL US US
MEDLINEa
WoS n
%
n
%
254 146 123 122 94 87 77 74 61 59 59 52 50
7.90 4.54 3.82 3.79 2.92 2.71 2.39 2.30 1.90 1.83 1.83 1.62 1.55
144 154 120 187 89 89 62 99 62 58 61 48 57
3.43 3.67 2.86 4.45 2.12 2.12 1.48 2.36 1.48 1.38 1.45 1.14 1.36
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226 Table 4 ‘Core’ journals in Scopusa in the field of pediatric sleep apnea.
223
Table 6 Most productive authors and their countries in three data-bases.
No.
Journal title
Country code
n
%
Author
Country code
WoS
MEDLINEa
Scopusb
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Arch. Dis. Childh. Eur. Respir. J. J. Pediatr. Child Health Paediatr. Respir. Rev. J. Laryngol. Otol. Int. J. Pediatr. Otorhinolaryngol. Eur. J. Pediatr. Int. J. Pediatr. Thorax Lancet J. Sleep Res. Clin. Otolaryngol. Allied Sci. Eur. J. Orthod.
US CH AU GB GB IE DE EG GB GB GB GB GB
38 29 19 19 19 17 16 15 15 14 13 10 9
5.58 4.26 2.79 2.79 2.79 2.50 2.35 2.20 2.20 2.05 1.91 1.47 1.32
David Gozal Carole L. Marcus Christian Guilleminault Leila Kheirandish-Gozal Andre Kahn Jose Groswasser Claude Gaultier Robert T. Brouillette Carol L. Rosen Louise M. O’Brien Thomas G. Keens Athanasios G. Kaditis S.L.D. Ward Konstantinos Gourgoulianis Daniel K. Ng Ron B. Mitchell Raouf S. Amin C.E. Hunt C.E. Sullivan Chung-Hong Chan Karen A. Waters Ka-Li Kwok
US US US US BE BE FR CA US US US GR US GR CN US US US AU CN AU CN
158 83 65 63 45 38 34 32 33 31 26 25 26 25 21 24 31 12 19 18 30 15
170 83 112 64 77 46 54 41 31 31 35 24 27 27 29 24 21 30 23 26 31 21
7 – 5 3 4 – 4 3 – 2 – – – – 10 – – – 5 2 7 6
a
Covers the period between 1973 and 2010.
MEDLINE, numerous subject categories had been assigned to one and the same publication. Similarly to WoS, the majority of the publications belonged simultaneously to the three main categories, i.e. of pediatrics (94.61%), respiratory system (91.99%), and neurosciences and neurology (90.73%). Surprisingly, next came the category of medical laboratory technology (with 1356 papers or 32.31% of a total of 4192 papers) followed by behavioural sciences (with 1226 papers or 29.21%) and psychology (with 1201 papers or 28.61%, respectively), surgery (with 1121 papers or 26.71%), otorhinolaryngology (with 1050 papers or 25.02%), cardiovascular system and cardiology (with 811 papers or 19.32%), dentistry, oral surgery and medicine (with 700 papers or 16.68%), physiology (with 670 papers or 15.96%), etc. This considerable variety of the subjects argued convincingly of the interdisciplinary nature of the narrow topic of pediatric sleep apnea. This statement was valid for the thematic and disciplinary belonging of the journals and scientific meetings, too. A detailed scientometric characteristic of the presence in these data-bases of four significant problems closely related to pediatric sleep apnea research, i.e. of adenotonsillectomy, obesity, noninvasive ventilation (or continuous positive airway pressure), and neurocognition is demonstrated in Tables 12–14. There are remarkable differences between these topics concerning the publication output and citation features. 4. Discussion The present results are similar to our previous work [12]. They convincingly demonstrate the rapid science advancement in the socially significant interdisciplinary field of obstructive sleep apnea in infancy and childhood. The complex analysis of the mutually linked aspects of internationalization and institutionalization by
a b
Covers the period between 1972 and 2010. Covers the period between 1973 and 2010.
means of properly selected constellations of scientometric parameters reveals the dynamic stratification of the forefront of this narrow topic, on the one hand, and the diversification of scientific communication channels worldwide, especially in the new millennium, on the other hand. Recent science expansion stresses, indeed. The relatively high number of review articles indicates a considerable degree of maturation of the topic. It is manifested by the large amount of specialized international scientific meetings where novelties are regularly presented, discussed and, fortunately, subsequently published in specialized proceedings and journals. The comparative assessment of WoS, MEDLINE and Scopus illustrates not only certain attractive advantages but also some disadvantages and pitfalls of these information-retrieval and information-storage systems for end users. There exist considerable differences between the three data-bases concerning the number of papers abstracted from one and the same journal preliminarily published by one and the same author during one and the same period. Besides they provide a variety of opportunities for automated problem-oriented scientometric analyses illustrated in Tables 12–14. Further improvements of the coverage scope of the primary scientific literature along with uninterrupted enrichment of processing capacities and steady refinement of indexing algorithms are needed.
Table 5 Journals containing the term of ‘sleep’ in their titles in three data-bases. Journal/country code of publication
Sleep (US) Sleep Medicine (NL) Journal of Sleep Research (GB) Sleep Medicine Reviews (GB) Sleep and Breathing (DE) Journal of Clinical Sleep Medicine (US) Somnologie (DE) Sleep and Hypnosis (TR) Waking and Sleeping (DE) a b
Covers the period between 1972 and 2010. Covers the period between 1973 and 2010.
MEDLINEa
WoS
Scopusb
n
%
n
%
n
%
254 59 35 28 17 – – – –
7.90 1.83 1.09 0.87 0.53 – – – –
144 61 26 24 23 31 – – –
3.43 1.45 0.62 0.57 0.55 0.74 – – –
– 2 13 6 2 – 5 1 1
– 0.03 1.91 0.09 0.03 – 0.07 0.01 0.01
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
224
Table 7 Conference proceedings with most publications abstracted in WoS. Conference title
No.
Number of events
7. 8. 9. 10.
Annual Meeting of the Associated Professional Sleep Societies Annual Meeting of the American Society of Pediatric Otolaryngology Annual International Conference of the IEEE – Engineering In Medicine and Biology Society Annual Meeting of the American Academy of Otolaryngology, Head and Neck Surgery International Congress of Pediatric Otorhinolaryngology Research Colloquium on Control of Breathing During Development: Apnea of the Newborn and in Sudden Infant Death Syndrome International Congress on Pediatric Pulmonology Congress of the European Sleep Research Society Congress of the World Association of Sleep Medicine Symposium on Diagnosis and Treatment of Sleep Breathing Disorders
Total
28
1. 2. 3. 4. 5. 6.
n
%
7 6 4 4 2 1
91 21 19 14 8 5
17.07 3.94 3.56 2.63 1.50 0.94
1 1 1 1
4 3 3 3
0.75 0.56 0.56 0.56
174
Table 8 Most productive scientific institutions in WoS and in Scopus.
32.64
Table 9 Publications in scientific events immediately devoted to sleep research.
Institution
Country code
WoS
Scopusa
University of Louisville Stanford University University of Pennsylvania Case Western Reserve University University of Sydney Harvard University Johns Hopkins University University of Michigan McGill University Free University of Brussels University of South California Children’s Hospital of Philadelphia University of Cincinnati University of Chicago Universita degli Study di Roma La Sapienza University of Arizona University of Washington Kwong Wah Hospital Chinese University of Hong Kong Children’s Hospital at Westmead Monash University Monash Medical Center
US US US US AU US US US CA BE US US US US IT
151 86 71 64 63 63 61 59 57 50 49 45 45 44 41
6 – – – 29 – – – – – – – – – 6
US US CN CN AU AU AU
34 33 24 28 17 25 16
– – 10 7 21 5 6
a
Publications
Covers the period between 1973 and 2010.
In the recent scientometric literature, there is a permanent interest in research internationalization [13,14]. Some probable indicators of research internationalization to serve policy-makers, research funders and research-performing organizations were suggested [15]. The analysis of the international research profiles of Europe’s top 10 largest multinational pharmaceutical companies based on publication counts and author address information shows that international research activity of European industry is significantly more oriented towards the US science base than vice versa [16].
n
Type
Publications Journal articles
Congresses Symposia Conferences Meetings Forum Workshop Total
Proceeding papers
Meeting abstracts
Total
7 4 2 1 1 1
3 7 1 1 1 –
5 – 1 – – 1
3 – – – – –
11 7 2 1 1 1
16
13
7
3
23
International collaboration is closely related to the visibility of science in some countries on the international scientific market [17,18], e.g. as examined by means of an international publication ratio [19]. The interuniversity, interregional and international collaboration networks generated by Spanish universities were studied by means of social network visualization techniques [20]. It was demonstrated that the international collaboration was implemented mainly with authors from European Union, North and Latin America. In The Netherlands, in 1988–2004, there is a high share of international research collaborations as collaborating within national research systems helps academia, firms and governmental organizations to overcome differences in norms, values and incentives [21]. Science institutionalization patterns are comprehensively studied like in cell biology [8], adipobiology [22], adipobiology and hypertension-related memory [23], nanotechnology [24], and memory research [9]. The successful creation of international joint laboratories by the French Centre National de la Recherche Scientifique and the German Max-Planck-Gesellschaft is an example of the institutionalization of the dynamics of previously selforganised international collaborations [25]. Such modern models
Table 10 Country and city distributions of events on sleep research. Countries
Countries Countries Countries Countries Countries Countries
Total
with cities of scientific events of authors with publications with cities of authors with institutions with cities of institutions with journals
12 11 11 11 11 6
Cities/authors/institutions/journals With 1
With 2
With 3
With 5
With 6
With 7
9 4 7 5 6 3
2 5 3 4 4 2
1 1 – 1 – 1
– – 1 – – –
– 1 – – 1 –
– – – 1 – –
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
225
Table 11 Number of presentations in events on sleep research and of their publications in the own country and abroad. Country codes of authors
Country of presentation/country of publication US
FR
IT
BE
FI
JP
AU
DE
CA
Other (7)
US (6) FR (3) IT (2) BE (2) FI (2) JP (2) AU (2) DE (1) CA (1) IN (1) CN (1)
1/3 0/1 0/2 0/1 – – 0/2 – 1/1 – –
2/1 2/1 – – – – 1/0 – – – –
– 0/1 – 1/0 0/1 – – – – – 0/1
– – – – – – – – – – –
– – – – 1/0 – – – – – –
– – – – – 2/0 – – – – –
– – – – – 0/1 1/0 – – – –
– 1/0 – 0/1 1/0 – – – – – 1/0
2/0 – – – – – – – – – –
1/2 – 2/0 1/0 0/1 0/1 – 1/1
Total (23)
2/10
5/2
1/3
0/0
1/0
2/0
1/1
3/1
2/0
6/6
1/1 –
Digits in brackets indicate the total number of published presentations by the authors of the corresponding country.
Table 12 Scientometric patterns of publications abstracted in WoS on four narrow topics related to pediatric sleep apnea. Parameter
Adenotonsillectomy
Obesity
Non-invasive ventilation
Neurocognition
Publications Countries of authors Journals Articles Reviews Conferences Conference papers/abstracts Editorials Letters Languages Year span Leading scientist Leading journal Leading institution Times cited without self-citation Citing articles Average citations per item Average citations per year h-Index
694 39 165 565 63 64 114 18 19 5 1985–2010 D. Gozal Int. J. Ped. Orl. Univ. Louisville 8139 3932 18.43 473.81 53
370 41 158 274 68 39 45 13 2 7 1991–2010 D. Gozal Sleep Univ. Louisville 9086 6331 28.13 520.40 51
164 32 86 140 22 13 14 1
84 18 42 61 18 5 5 2 – 3 1995–2010 D. Gozal Pediatrics Univ. Louisville 2237 1209 30.44 170.47 24
6 1991–2010 C. Guilleminault Sleep Stanford Univ. 2262 1792 15.49 127.05 27
Table 13 Scientometric patterns of publications abstracted in MEDLINE on four narrow topics related to pediatric sleep apnea. Parameter
Adenotonsillectomy
Obesity
Non-invasive ventilation
Neurocognition
Publications Journals Articles Reviews Editorial Letter Comparative study Clinical trial Controlled clin. trial Meta-analysis Multi center study Comment Randomized trial Year span Leading scientist
798 239 758 121 6 31 86 38 11 5 16 28 30 1976–2010 D. Gozal
447 211 419 129 6 15 34 4 3
157 95 155 31 1 1 8 6 2
87 49 85 32 2
5 21 2 1972–2010 D. Gozal
3
7 2 1 1 1
4 1983–2010 C.E. Sullivan
1995–2010 D. Gozal
M. Milkov / International Journal of Pediatric Otorhinolaryngology 76 (2012) 219–226
226
Table 14 Scientometric patterns of publications abstracted in Scopus on four narrow topics related to pediatric sleep apnea. Parameter
Adenotonsillectomy
Obesity
Non-invasive ventilation
Neurocognition
Publications Countries of authors Journals Articles Reviews Conference papers Editorial Letter Languages Year span Leading scientist Leading journal Leading institution
315 29 126 205 80 10 6 9 10 1987–2010 D. Gozal Int. J. Ped. Orl. Univ. Louisville
169 23 101 95 63 5 3
19 7 15 11 4
40 11 31 20 19
1
1
8 1994–2010 D. Gozal Ped. Pulmonol. Cincinnati Hosp.
4 1983–2010 D. Gozal Resp. Care Univ. Calgari
7 2000–2010 D. Gozal Sleep Med. Rev. Univ. Louisville
should be widely popularized among scientists themselves, science managers and policy makers in sleep apnea research, too. Obviously, modern science becomes more and more interdisciplinary [26]. Our results provide convincing evidence that respiratory sleep disorders present with increasing interdisciplinarity. Besides they promote further international research of patient’s individual health-related quality of life, e.g., by a validated quality of life survey of pediatric obstructive sleep apnea [27]. It could be concluded that this scientometric investigation has created a comprehensive problem-oriented data-base containing systematized files with the researchers’ names, addresses and publications designed mainly for the scientists from smaller countries. Its effective usage could contribute to the further improvement of their scientific communications and international collaboration with eminent colleagues from all over the world. Conflict of interest Herewith the author declares no conflict of interest at all. Funding There is no financial support for the present study. References [1] E.F. Boss, D.F. Smith, S.L. Ishman, Racial/ethnic and socioeconomic disparities in the diagnosis and treatment of sleep-disordered breathing in children, Int. J. Pediatr. Otorhinolaryngol. 75 (2011) 299–307. [2] J.L. Goodwin, K.L. Kaemingk, R.F. Fregosi, G.M. Rosen, W.J. Morgan, D.L. Sherrill, et al., Clinical outcomes associated with sleep-disordered breathing in Caucasian and Hispanic children – the Tucson Children’s Assessment of Sleep Apnea study (TuCASA), Sleep 26 (2003) 587–591. [3] L. Kheirandish-Gozal, R. Bhattacharjee, J. Kim, H.B. Clair, D. Gozal, Endothelial progenitor cells and vascular dysfunction in children with obstructive sleep apnea, Am. J. Respir. Crit. Care Med. 182 (2010) 92–97. [4] M. Milkov, Z. Tonchev, Surgical treatments of sleep-determined respiratory disorders in a historical aspect, Otorinolaringol. Mezhdunar. Byul. (Varna) 4 (2) (2008) 26–31 (in Bulgarian). [5] P. Nedev, G. Boyadzhiev, M. Milkov, Types of interventions for treatment of snoring and obstructive sleep apnea, Otorinolaringol. Mezhdunar. Byul. (Varna) 4 (2) (2008) 47–51 (in Bulgarian). [6] M. Milkov, Diagnosis of sleep disorders, Otorinolaringol. Mezhdunar. Byul. (Varna) 5 (4) (2009) 31–35 (in Bulgarian).
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