{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,10]],"date-time":"2026-02-10T18:18:54Z","timestamp":1770747534465,"version":"3.49.0"},"reference-count":47,"publisher":"Springer Science and Business Media LLC","issue":"S3","content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["BMC Syst Biol"],"published-print":{"date-parts":[[2011,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n          <jats:sec>\n            <jats:title>Background<\/jats:title>\n            <jats:p>A phylogenetic tree, showing ancestral relations among organisms, is commonly represented as a rooted tree with sets of bifurcating branches (dichotomies) for simplicity, although polytomies (multifurcating branches) may reflect more accurate evolutionary relationships. To represent the true evolutionary relationships, it is important to systematically identify the polytomies from a bifurcating tree and generate a taxonomy-compatible multifurcating tree. For this purpose we propose a novel approach, \"PolyPhy\", which would classify a set of bifurcating branches of a phylogenetic tree into a set of branches with dichotomies and polytomies by considering genome distances among genomes and tree topological properties.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Results<\/jats:title>\n            <jats:p>PolyPhy employs a machine learning technique, BLR (Bayesian logistic regression) classifier, to identify possible bifurcating subtrees as polytomies from the trees resulted from ComPhy. Other than considering genome-scale distances between all pairs of species, PolyPhy also takes into account different properties of tree topology between dichotomy and polytomy, such as long-branch retraction and short-branch contraction, and quantifies these properties into comparable rates among different sub-branches. We extract three tree topological features, 'LR' (Leaf rate), 'IntraR' (Intra-subset branch rate) and 'InterR' (Inter-subset branch rate), all of which are calculated from bifurcating tree branch sets for classification. We have achieved F-measure (balanced measure between precision and recall) of 81% with about 0.9 area under the curve (AUC) of ROC.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Conclusions<\/jats:title>\n            <jats:p>PolyPhy is a fast and robust method to identify polytomies from phylogenetic trees based on genome-wide inference of evolutionary relationships among genomes. The software package and test data can be downloaded from <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"http:\/\/digbio.missouri.edu\/ComPhy\/phyloTreeBiNonBi-1.0.zip\" ext-link-type=\"uri\">http:\/\/digbio.missouri.edu\/ComPhy\/phyloTreeBiNonBi-1.0.zip<\/jats:ext-link>.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1186\/1752-0509-5-s3-s2","type":"journal-article","created":{"date-parts":[[2011,12,23]],"date-time":"2011-12-23T19:18:55Z","timestamp":1324667935000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Polytomy identification in microbial phylogenetic reconstruction"],"prefix":"10.1186","volume":"5","author":[{"given":"Guan Ning","family":"Lin","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chao","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dong","family":"Xu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2011,12,23]]},"reference":[{"key":"810_CR1","doi-asserted-by":"publisher","first-page":"e352","DOI":"10.1371\/journal.pbio.0040352","volume":"4","author":"A Rokas","year":"2006","unstructured":"Rokas A, Carroll SB: Bushes in the tree of life. PLoS Biol. 2006, 4: e352-10.1371\/journal.pbio.0040352.","journal-title":"PLoS Biol"},{"key":"810_CR2","doi-asserted-by":"publisher","first-page":"365","DOI":"10.1111\/j.1096-0031.1989.tb00569.x","volume":"5","author":"DR Maddison","year":"1989","unstructured":"Maddison DR: Reconstructing character evolution on polytomous cladograms. Cladistics. 1989, 5: 365-377. 10.1111\/j.1096-0031.1989.tb00569.x.","journal-title":"Cladistics"},{"key":"810_CR3","first-page":"1","volume-title":"Am Nat","author":"J Felsenstein","year":"1985","unstructured":"Felsenstein J: Phylogenies and the comparative method. Am Nat. 1985, 1-15. 10.1086\/284325."},{"key":"810_CR4","doi-asserted-by":"publisher","first-page":"119","DOI":"10.1098\/rstb.1989.0106","volume":"326","author":"A Grafen","year":"1989","unstructured":"Grafen A: The phylogenetic regression. Philos Trans R Soc Lond B Biol Sci. 1989, 326: 119-157. 10.1098\/rstb.1989.0106.","journal-title":"Philos Trans R Soc Lond B Biol Sci"},{"key":"810_CR5","doi-asserted-by":"publisher","first-page":"11","DOI":"10.1017\/S0016672304007013","volume":"84","author":"JA Coyne","year":"2004","unstructured":"Coyne JA, Elwyn S, Kim SY, Llopart A: Genetic studies of two sister species in the Drosophila melanogaster subgroup, D. yakuba and D. santomea. Genet Res. 2004, 84: 11-26. 10.1017\/S0016672304007013.","journal-title":"Genet Res"},{"key":"810_CR6","doi-asserted-by":"crossref","first-page":"1913","DOI":"10.1093\/genetics\/156.4.1913","volume":"156","author":"RM Kliman","year":"2000","unstructured":"Kliman RM, Andolfatto P, Coyne JA, Depaulis F, Kreitman M, Berry AJ, McCarter J, Wakeley J, Hey J: The population genetics of the origin and divergence of the Drosophila simulans complex species. Genetics. 2000, 156: 1913-1931.","journal-title":"Genetics"},{"key":"810_CR7","doi-asserted-by":"publisher","first-page":"2057","DOI":"10.1093\/oxfordjournals.molbev.a003747","volume":"18","author":"K Takahashi","year":"2001","unstructured":"Takahashi K, Terai Y, Nishida M, Okada N: Phylogenetic relationships and ancient incomplete lineage sorting among cichlid fishes in Lake Tanganyika as revealed by analysis of the insertion of retroposons. Mol Biol Evol. 2001, 18: 2057-2066. 10.1093\/oxfordjournals.molbev.a003747.","journal-title":"Mol Biol Evol"},{"key":"810_CR8","doi-asserted-by":"publisher","first-page":"1947","DOI":"10.1098\/rstb.2006.1923","volume":"361","author":"JW Taylor","year":"2006","unstructured":"Taylor JW, Turner E, Townsend JP, Dettman JR, Jacobson D: Eukaryotic microbes, species recognition and the geographic limits of species: examples from the kingdom Fungi. Philos Trans R Soc Lond B Biol Sci. 2006, 361: 1947-1963. 10.1098\/rstb.2006.1923.","journal-title":"Philos Trans R Soc Lond B Biol Sci"},{"key":"810_CR9","doi-asserted-by":"publisher","first-page":"1377","DOI":"10.1099\/ijs.0.01952-0","volume":"52","author":"BP Hedlund","year":"2002","unstructured":"Hedlund BP, Staley JT: Phylogeny of the genus Simonsiella and other members of the Neisseriaceae. Int J Syst Evol Microbiol. 2002, 52: 1377-1382. 10.1099\/ijs.0.01952-0.","journal-title":"Int J Syst Evol Microbiol"},{"key":"810_CR10","doi-asserted-by":"crossref","first-page":"4765","DOI":"10.1128\/JB.180.18.4765-4774.1998","volume":"180","author":"P Hugenholtz","year":"1998","unstructured":"Hugenholtz P, Goebel BM, Pace NR: Impact of culture-independent studies on the emerging phylogenetic view of bacterial diversity. J Bacteriol. 1998, 180: 4765-4774.","journal-title":"J Bacteriol"},{"key":"810_CR11","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1080\/106351598260987","volume":"47","author":"DM Hillis","year":"1998","unstructured":"Hillis DM: Taxonomic sampling, phylogenetic accuracy, and investigator bias. Syst Biol. 1998, 47: 3-8. 10.1080\/106351598260987.","journal-title":"Syst Biol"},{"key":"810_CR12","first-page":"53","volume-title":"Microbial Phylogeny and Evolution: Concepts and Controversies","author":"NR Pace","year":"2005","unstructured":"Pace NR: The large-scale structure of the Tree of Life. Microbial Phylogeny and Evolution: Concepts and Controversies. 2005, 53-69."},{"key":"810_CR13","doi-asserted-by":"publisher","first-page":"D39","DOI":"10.1093\/nar\/gki062","volume":"33","author":"DL Wheeler","year":"2005","unstructured":"Wheeler DL, Barrett T, Benson DA, Bryant SH, Canese K, Church DM, DiCuccio M, Edgar R, Federhen S, Helmberg W: Database resources of the National Center for Biotechnology Information. Nucleic Acids Res. 2005, 33: D39-45. 10.1093\/nar\/gki062.","journal-title":"Nucleic Acids Res"},{"key":"810_CR14","doi-asserted-by":"publisher","first-page":"699","DOI":"10.1093\/bioinformatics\/btk040","volume":"22","author":"JC Chiu","year":"2006","unstructured":"Chiu JC, Lee EK, Egan MG, Sarkar IN, Coruzzi GM, DeSalle R: OrthologID: automation of genome-scale ortholog identification within a parsimony framework. Bioinformatics. 2006, 22: 699-707. 10.1093\/bioinformatics\/btk040.","journal-title":"Bioinformatics"},{"key":"810_CR15","doi-asserted-by":"publisher","first-page":"D572","DOI":"10.1093\/nar\/gkj118","volume":"34","author":"H Li","year":"2006","unstructured":"Li H, Coghlan A, Ruan J, Coin LJ, Heriche JK, Osmotherly L, Li R, Liu T, Zhang Z, Bolund L: TreeFam: a curated database of phylogenetic trees of animal gene families. Nucleic Acids Res. 2006, 34: D572-580. 10.1093\/nar\/gkj118.","journal-title":"Nucleic Acids Res"},{"key":"810_CR16","doi-asserted-by":"publisher","first-page":"D735","DOI":"10.1093\/nar\/gkm1005","volume":"36","author":"J Ruan","year":"2008","unstructured":"Ruan J, Li H, Chen Z, Coghlan A, Coin LJ, Guo Y, Heriche JK, Hu Y, Kristiansen K, Li R: TreeFam: 2008 Update. Nucleic Acids Res. 2008, 36: D735-740. 10.1093\/nar\/gkm1005.","journal-title":"Nucleic Acids Res"},{"key":"810_CR17","doi-asserted-by":"publisher","first-page":"481","DOI":"10.1016\/S1055-7903(02)00033-7","volume":"23","author":"MP Simmons","year":"2002","unstructured":"Simmons MP, Freudenstein JV: Uninode coding vs gene tree parsimony for phylogenetic reconstruction using duplicate genes. Mol Phylogenet Evol. 2002, 23: 481-498. 10.1016\/S1055-7903(02)00033-7.","journal-title":"Mol Phylogenet Evol"},{"key":"810_CR18","doi-asserted-by":"publisher","first-page":"365","DOI":"10.1111\/j.1096-0031.1989.tb00569.x","volume":"5","author":"W Maddison","year":"1989","unstructured":"Maddison W: Reconstructing character evolution on polytomous cladograms. Cladistics. 1989, 5: 365-377. 10.1111\/j.1096-0031.1989.tb00569.x.","journal-title":"Cladistics"},{"key":"810_CR19","doi-asserted-by":"publisher","first-page":"104","DOI":"10.1016\/0169-5347(94)90207-0","volume":"9","author":"GA Hoelzer","year":"1994","unstructured":"Hoelzer GA, Meinick DJ: Patterns of speciation and limits to phylogenetic resolution. Trends Ecol Evol. 1994, 9: 104-107. 10.1016\/0169-5347(94)90207-0.","journal-title":"Trends Ecol Evol"},{"key":"810_CR20","doi-asserted-by":"publisher","first-page":"258","DOI":"10.1016\/j.tree.2007.01.012","volume":"22","author":"JB Whitfield","year":"2007","unstructured":"Whitfield JB, Lockhart PJ: Deciphering ancient rapid radiations. Trends Ecol Evol. 2007, 22: 258-265. 10.1016\/j.tree.2007.01.012.","journal-title":"Trends Ecol Evol"},{"key":"810_CR21","doi-asserted-by":"publisher","first-page":"1709","DOI":"10.1093\/bioinformatics\/bti175","volume":"21","author":"KM Chan","year":"2005","unstructured":"Chan KM, Moore BR: Symmetree: whole-tree analysis of differential diversification rates. Bioinformatics. 2005, 21: 1709-1710. 10.1093\/bioinformatics\/bti175.","journal-title":"Bioinformatics"},{"key":"810_CR22","volume-title":"Curr Protoc Bioinformatics","author":"JC Wilgenbusch","year":"2003","unstructured":"Wilgenbusch JC, Swofford D: Inferring evolutionary trees with PAUP*. Curr Protoc Bioinformatics. 2003, Chapter 6: Unit 6 4"},{"key":"810_CR23","first-page":"164","volume-title":"Cladistics 5","author":"J Felsenstein","year":"1989","unstructured":"Felsenstein J: PHYLIP -- Phylogeny inference package (Version 3.2). Cladistics 5. 1989, 164-166."},{"key":"810_CR24","doi-asserted-by":"publisher","first-page":"254","DOI":"10.1093\/molbev\/msj030","volume":"23","author":"DH Huson","year":"2006","unstructured":"Huson DH, Bryant D: Application of phylogenetic networks in evolutionary studies. Mol Biol Evol. 2006, 23: 254-267. 10.1093\/molbev\/msj030.","journal-title":"Mol Biol Evol"},{"issue":"Suppl 1","key":"810_CR25","doi-asserted-by":"publisher","first-page":"S5","DOI":"10.1186\/1471-2105-10-S1-S5","volume":"10","author":"GN Lin","year":"2009","unstructured":"Lin GN, Cai Z, Lin G, Chakraborty S, Xu D: ComPhy: prokaryotic composite distance phylogenies inferred from whole-genome gene sets. BMC Bioinformatics. 2009, 10 (Suppl 1): S5-10.1186\/1471-2105-10-S1-S5.","journal-title":"BMC Bioinformatics"},{"key":"810_CR26","volume-title":"Proceedings of the 26th Annual International ACM SIGIR Conference on Research and Development in Informaion Retrieval","author":"I Soboroff","year":"2003","unstructured":"Soboroff I, Robertson S: Building a filtering test collection for TREC 2002. Proceedings of the 26th Annual International ACM SIGIR Conference on Research and Development in Informaion Retrieval. 2003"},{"key":"810_CR27","volume-title":"Butterworth","author":"v Rijsbergen","year":"1979","unstructured":"Rijsbergen v, J C: Information Retrieval. Butterworth. 1979, 2","edition":"2"},{"key":"810_CR28","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1007\/s10791-008-9076-6","volume":"12","author":"W Hersh","year":"2009","unstructured":"Hersh W, Voorhees E: TREC genomics special issue overview. Information Retrieval. 2009, 12: 1-15. 10.1007\/s10791-008-9076-6.","journal-title":"Information Retrieval"},{"key":"810_CR29","doi-asserted-by":"publisher","first-page":"230","DOI":"10.1038\/msb.2008.66","volume":"4","author":"B de Chassey","year":"2008","unstructured":"de Chassey B, Navratil V, Tafforeau L, Hiet MS, Aublin-Gex A, Agaugue S, Meiffren G, Pradezynski F, Faria BF, Chantier T: Hepatitis C virus infection protein network. Mol Syst Biol. 2008, 4: 230-10.1038\/msb.2008.66.","journal-title":"Mol Syst Biol"},{"key":"810_CR30","doi-asserted-by":"publisher","first-page":"REVIEWS0003","DOI":"10.1186\/gb-2002-3-2-reviews0003","volume":"3","author":"P Hugenholtz","year":"2002","unstructured":"Hugenholtz P: Exploring prokaryotic diversity in the genomic era. Genome Biol. 2002, 3: REVIEWS0003-10.1186\/gb-2002-3-2-reviews0003.","journal-title":"Genome Biol"},{"key":"810_CR31","doi-asserted-by":"publisher","first-page":"2329","DOI":"10.1093\/bioinformatics\/bth324","volume":"21","author":"SR Henz","year":"2005","unstructured":"Henz SR, Huson DH, Auch AF, Nieselt-Struwe K, Schuster SC: Whole-genome prokaryotic phylogeny. Bioinformatics. 2005, 21: 2329-2335. 10.1093\/bioinformatics\/bth324.","journal-title":"Bioinformatics"},{"key":"810_CR32","doi-asserted-by":"publisher","first-page":"5069","DOI":"10.1128\/AEM.03006-05","volume":"72","author":"TZ DeSantis","year":"2006","unstructured":"DeSantis TZ, Hugenholtz P, Larsen N, Rojas M, Brodie EL, Keller K, Huber T, Dalevi D, Hu P, Andersen GL: Greengenes, a chimera-checked 16S rRNA gene database and workbench compatible with ARB. Appl Environ Microbiol. 2006, 72: 5069-5072. 10.1128\/AEM.03006-05.","journal-title":"Appl Environ Microbiol"},{"key":"810_CR33","first-page":"406","volume":"4","author":"N Saitou","year":"1987","unstructured":"Saitou N, Nei M: The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol. 1987, 4: 406-425.","journal-title":"Mol Biol Evol"},{"key":"810_CR34","first-page":"729","volume":"5","author":"JA Studier","year":"1988","unstructured":"Studier JA, Keppler KJ: A note on the neighbor-joining algorithm of Saitou and Nei. Mol Biol Evol. 1988, 5: 729-731.","journal-title":"Mol Biol Evol"},{"key":"810_CR35","doi-asserted-by":"publisher","first-page":"1376","DOI":"10.1126\/science.1182300","volume":"327","author":"S Roch","year":"2010","unstructured":"Roch S: Toward extracting all phylogenetic information from matrices of evolutionary distances. Science. 2010, 327: 1376-1379. 10.1126\/science.1182300.","journal-title":"Science"},{"key":"810_CR36","doi-asserted-by":"publisher","first-page":"1334","DOI":"10.1126\/science.1187797","volume":"327","author":"ES Allman","year":"2010","unstructured":"Allman ES, Rhodes JA: Evolution. Trees, fast and accurate. Science. 2010, 327: 1334-1335. 10.1126\/science.1187797.","journal-title":"Science"},{"key":"810_CR37","doi-asserted-by":"publisher","first-page":"3795","DOI":"10.1093\/nar\/gkg573","volume":"31","author":"R Lopez","year":"2003","unstructured":"Lopez R, Silventoinen V, Robinson S, Kibria A, Gish W: WU-Blast2 server at the European Bioinformatics Institute. Nucleic Acids Res. 2003, 31: 3795-3798. 10.1093\/nar\/gkg573.","journal-title":"Nucleic Acids Res"},{"key":"810_CR38","doi-asserted-by":"publisher","first-page":"1792","DOI":"10.1093\/nar\/gkh340","volume":"32","author":"RC Edgar","year":"2004","unstructured":"Edgar RC: MUSCLE: multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Res. 2004, 32: 1792-1797. 10.1093\/nar\/gkh340.","journal-title":"Nucleic Acids Res"},{"key":"810_CR39","doi-asserted-by":"publisher","first-page":"276","DOI":"10.1016\/S0168-9525(00)02024-2","volume":"16","author":"P Rice","year":"2000","unstructured":"Rice P, Longden I, Bleasby A: EMBOSS: the European Molecular Biology Open Software Suite. Trends Genet. 2000, 16: 276-277. 10.1016\/S0168-9525(00)02024-2.","journal-title":"Trends Genet"},{"key":"810_CR40","doi-asserted-by":"publisher","first-page":"1456","DOI":"10.1093\/molbev\/msi134","volume":"22","author":"E Belda","year":"2005","unstructured":"Belda E, Moya A, Silva FJ: Genome rearrangement distances and gene order phylogeny in gamma-Proteobacteria. Mol Biol Evol. 2005, 22: 1456-1467. 10.1093\/molbev\/msi134.","journal-title":"Mol Biol Evol"},{"key":"810_CR41","doi-asserted-by":"publisher","first-page":"e3837","DOI":"10.1371\/journal.pone.0003837","volume":"3","author":"H Luo","year":"2008","unstructured":"Luo H, Shi J, Arndt W, Tang J, Friedman R: Gene order phylogeny of the genus Prochlorococcus. PLoS One. 2008, 3: e3837-10.1371\/journal.pone.0003837.","journal-title":"PLoS One"},{"key":"810_CR42","volume-title":"Stat Appl Genet Mol Biol","author":"F Strimenopoulou","year":"2008","unstructured":"Strimenopoulou F, Brown PJ: Empirical Bayes logistic regression. Stat Appl Genet Mol Biol. 2008, 7: Article9"},{"key":"810_CR43","doi-asserted-by":"publisher","first-page":"32","DOI":"10.1093\/biostatistics\/kxj030","volume":"8","author":"TG Clark","year":"2007","unstructured":"Clark TG, De Iorio M, Griffiths RC: Bayesian logistic regression using a perfect phylogeny. Biostatistics. 2007, 8: 32-52. 10.1093\/biostatistics\/kxj030.","journal-title":"Biostatistics"},{"key":"810_CR44","doi-asserted-by":"publisher","first-page":"2348","DOI":"10.1093\/bioinformatics\/btl386","volume":"22","author":"GC Cawley","year":"2006","unstructured":"Cawley GC, Talbot NL: Gene selection in cancer classification using sparse logistic regression with Bayesian regularization. Bioinformatics. 2006, 22: 2348-2355. 10.1093\/bioinformatics\/btl386.","journal-title":"Bioinformatics"},{"key":"810_CR45","doi-asserted-by":"publisher","first-page":"455","DOI":"10.1080\/10635150590945313","volume":"54","author":"Z Yang","year":"2005","unstructured":"Yang Z, Rannala B: Branch-length prior influences Bayesian posterior probability of phylogeny. Syst Biol. 2005, 54: 455-470. 10.1080\/10635150590945313.","journal-title":"Syst Biol"},{"key":"810_CR46","doi-asserted-by":"publisher","first-page":"637","DOI":"10.1080\/10635150600865567","volume":"55","author":"C Venditti","year":"2006","unstructured":"Venditti C, Meade A, Pagel M: Detecting the node-density artifact in phylogeny reconstruction. Syst Biol. 2006, 55: 637-643. 10.1080\/10635150600865567.","journal-title":"Syst Biol"},{"key":"810_CR47","doi-asserted-by":"publisher","first-page":"108","DOI":"10.1016\/j.mbs.2007.01.005","volume":"209","author":"O Francois","year":"2007","unstructured":"Francois O, Mioland C: Gaussian approximations for phylogenetic branch length statistics under stochastic models of biodiversity. Math Biosci. 2007, 209: 108-123. 10.1016\/j.mbs.2007.01.005.","journal-title":"Math Biosci"}],"container-title":["BMC Systems Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1186\/1752-0509-5-S3-S2.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,9,1]],"date-time":"2021-09-01T18:08:18Z","timestamp":1630519698000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmcsystbiol.biomedcentral.com\/articles\/10.1186\/1752-0509-5-S3-S2"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2011,12]]},"references-count":47,"journal-issue":{"issue":"S3","published-print":{"date-parts":[[2011,12]]}},"alternative-id":["810"],"URL":"https:\/\/doi.org\/10.1186\/1752-0509-5-s3-s2","relation":{},"ISSN":["1752-0509"],"issn-type":[{"value":"1752-0509","type":"electronic"}],"subject":[],"published":{"date-parts":[[2011,12]]},"assertion":[{"value":"23 December 2011","order":1,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}}],"article-number":"S2"}}