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Wyszukujesz frazę "Martin, W.F." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Application and comparative performance of network modularity algorithms to ecological communities classification
Autorzy:
Thiergart, T.
Schmitz, U.
Landan, G.
Martin, W.F.
Dagan, T.
Powiązania:
https://bibliotekanauki.pl/articles/59149.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
ecological informatics
comparative performance
information visualization
vegetation
phytosociology
network
ecological community
classification
Opis:
Network modularity is a well-studied large-scale connectivity pattern in networks. The detection of modules in real networks constitutes a crucial step towards a description of the network building blocks and their evolutionary dynamics. The performance of modularity detection algorithms is commonly quantified using simulated networks data. However, a comparison of the modularity algorithms utility for real biological data is scarce. Here we investigate the utility of network modularity algorithms for the classification of ecological plant communities. Plant community classification by the traditional approaches requires prior knowledge about the characteristic and differential species, which are derived from a manual inspection of vegetation tables. Using the raw species abundance data we constructed six different networks that vary in their edge definitions. Four network modularity algorithms were examined for their ability to detect the traditionally recognized plant communities. The use of more restrictive edge definitions significantly increased the accuracy of community detection, that is, the correspondence between network-based and traditional community classification. Random-walk based modularity methods yielded slightly better results than approaches based on the modularity function. For the whole network, the average agreement between the manual classification and the network-based modules is 76% with varying congruence levels for different communities ranging between 11% and 100%. The network-based approach recovered the known ecological gradient from riverside – sand and gravel bank vegetation – to dryer habitats like semidry grassland on dykes. Our results show that networks modularity algorithms offer new avenues of pursuit for the computational analysis of species communities.
Źródło:
Acta Societatis Botanicorum Poloniae; 2014, 83, 2
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plastid origin: who, when and why?
Autorzy:
Ku, Chuan
Roettger, M.
Zimorski, V.
Nelsen-Sathi, S.
Sousa, F.L.
Martin, W.F.
Powiązania:
https://bibliotekanauki.pl/articles/59262.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
plastid
Cyanoprokaryota
endosymbiosis
evolution
gene transfer
genomics
organelle
photosynthesis
phylogenesis
Opis:
The origin of plastids is best explained by endosymbiotic theory, which dates back to the early 1900s. Three lines of evidence based on protein import machineries and molecular phylogenies of eukaryote (host) and cyanobacterial (endosymbiont) genes point to a single origin of primary plastids, a unique and important event that successfully transferred two photosystems and oxygenic photosynthesis from prokaryotes to eukaryotes. The nature of the cyanobacterial lineage from which plastids originated has been a topic of investigation. Recent studies have focused on the branching position of the plastid lineage in the phylogeny based on cyanobacterial core genes, that is, genes shared by all cyanobacteria and plastids. These studies have delivered conflicting results, however. In addition, the core genes represent only a very small portion of cyanobacterial genomes and may not be a good proxy for the rest of the ancestral plastid genome. Information in plant nuclear genomes, where most genes that entered the eukaryotic lineage through acquisition from the plastid ancestor reside, suggests that heterocyst-forming cyanobacteria in Stanier’s sections IV and V are most similar to the plastid ancestor in terms of gene complement and sequence conservation, which is in agreement with models suggesting an important role of nitrogen fixation in symbioses involving cyanobacteria. Plastid origin is an ancient event that involved a prokaryotic symbiont and a eukaryotic host, organisms with different histories and genome evolutionary processes. The different modes of genome evolution in prokaryotes and eukaryotes bear upon our interpretations of plastid phylogeny.
Źródło:
Acta Societatis Botanicorum Poloniae; 2014, 83, 4
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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