Search results for "Tree"
showing 10 items of 1841 documents
Bridging data mining and semantic web
2016
Nowadays Semantic Web is widely adopted standard of knowledge representation. Hence, knowledge engineers are applying sophisticated methods to capture, discover and represent knowledge in Semantic Web form. Studies show that, to represent knowledge in Semantic Web standard, data mining techniques such as Decision Trees, Association Rules, etc., play an important role. These techniques are implemented in publicly available Data Mining tools. These tools represent knowledge discovered in human readable format and some tools use Predictive Model Markup language (PMML). PMML is an XML based model for data mining model representation that fails to address the representation of the semantics of t…
Pseudodalatias henarejensisnov. sp. a new pseudodalatiid (Elasmobranchii) from the Middle Triassic of Spain
2009
ABSTRACT Pseudodalatiids, a chondrichthyan family of uncertain phylogenetic affinities, have been hitherto exclusively known from the tooth-based species Pseudodalatias barnstonensis (Sykes, 1971), which has a stratigraphic range restricted to the Upper Triassic of Europe. Pseudodalatias presents a characteristic dentition which allows it to hold and cut its prey, showing a neoselachian design, but lacking the triple-layered enameloid microstructure of neoselachian teeth. The discovery of Pseudodalatias henarejensis nov. sp. in the Ladinian of Spain extends the stratigraphical range and the palaeogeographical distribution of this family. This new species also demonstrates that a cutting-clu…
Reconstitution du squelette d'astérides fossiles à partir d'ossicules isolés : intérêt taxinomique et phylogénétique
1999
Abstract Dissociated ossicles of asteroids are frequent in neritic sediments. Until now, this material was mainly used in the identification of species. A new method, associating a morphological analysis and counting of plates, allows the architecture of the skeleton and the shape of the body to be reconstructed. This method provides new elements for taxonomic and phylogenetic comparisons. It also provides indications on the adaptation of the asteroids to their environment. In geological beds, frequencies of the different kinds of plates will allow qualification of bioerosion and taphonomic sorting.
On the Fractal Structure of Evolutionary Trees
2002
We analyse in terms of a fractal tree the time sequences of major evolutionary leaps at various scales: from the scale of the “global” tree of life (appearance of life to homeothermy), to the distinct scales of organization of clades, such as sauropod and theropod dinosaurs, North American equids, rodents, primates including hominids, and echinoderms. We also apply this type of model to the acceleration observed in the economic crisis/no-crisis pattern in Western and pre-Columbian civilizations. In each case we find that these data are consistent with a log-periodic law of acceleration or deceleration, to a high level of statistical significance. Such a law is characterized by a critical ep…
Neoendemic ground beetles and private tree haplotypes: two independent proxies attest a moderate last glacial maximum summer temperature depression o…
2011
Abstract Previous findings regarding the Last Glacial Maximum LGM summer temperature depression (maxΔT in July) on the Tibetan Plateau varied over a large range (between 0 and 9 °C). Geologic proxies usually provided higher values than palynological data. Because of this wide temperature range, it was hitherto impossible to reconstruct the glacial environment of the Tibetan Plateau. Here, we present for the first time data indicating that local neoendemics of modern species groups are promising proxies for assessing the LGM temperature depression in Tibet. We used biogeographical and phylogenetic data from small, wingless edaphous ground beetles of the genus Trechus , and from private junip…
Diversity and Evolution of papillomaviruses
2017
1.1. Introducción Con el fin de averiguar las causas de las devastadoras epidemias de finales del siglo XIX, se llevaron a cabo diferentes estudios que dieron como resultado la identificación de unos nuevos agentes infecciosos, para los que se acuñó el nombre de “virus”. Desde entonces el descubrimiento de nuevos virus ha sido incesante, lo que llevó, en los años 70, a la creación de un organismo encargado de desarrollar, refinar y mantener la clasificación taxonómica de los virus, el Comité Internacional de Taxonomía Viral (ICTV), en el seno de la Unión Internacional de Sociedades Microbiológicas (IUMS). En 2014 este organismo había reconocido 3.186 especies virales pertenecientes a 104 fa…
Paraphyly of the Blue Tit (Parus caeruleus) suggested from cytochrome b sequences
2002
The phylogenetic relationships of the Blue Tit-Azure Tit assemblage (genus Parus; Aves: Passeriformes) were studied using mitochondrial DNA sequences of 24 specimens representing seven subspecies from Eurasia and North Africa. Previous work based on comparative morphological and acoustic data suggested a division of the Blue Tit (Parus caeruleus) into two species. Our analyses clearly indicate that the Blue Tit represents a paraphyletic assemblage, including a European/Middle Asian clade that is the sister group to the Azure Tit (Parus cyanus) and a North African clade. The North African clade (teneriffae subspecies group) is a sister group to the European Blue Tit/Azure Tit clade. We sugge…
A novel family of tRNA-derived SINEs in the colugo and two new retrotransposable markers separating dermopterans from primates.
2003
Abstract Short interspersed nuclear elements (SINEs) provide a near homoplasy free and copious source of molecular evolutionary markers with precisely defined character polarity. Used as molecular cladistic markers in presence/absence analyses, they represent a powerful complement to phylogenetic reconstructions that are based on sequence comparisons on the level of nucleotide substitutions. Recent sequence comparisons of large data sets incorporating a broad eutherian taxonomic sample have led to considerations of the different primate infraorders to constitute a paraphyletic group. Statistically significant support against the monophyly of primates has been obtained by clustering the flyi…
Platyzoan paraphyly based on phylogenomic data supports a noncoelomate ancestry of spiralia.
2014
Based on molecular data three major clades have been recognized within Bilateria: Deuterostomia, Ecdysozoa, and Spiralia. Within Spiralia, small-sized and simply organized animals such as flatworms, gastrotrichs, and gnathostomulids have recently been grouped together as Platyzoa. However, the representation of putative platyzoans was low in the respective molecular phylogenetic studies, in terms of both, taxon number and sequence data. Furthermore, increased substitution rates in platyzoan taxa raised the possibility that monophyletic Platyzoa represents an artifact due to long-branch attraction. In order to overcome such problems, we employed a phylogenomic approach, thereby substantially…
Independent host switching events by digenean parasites of cetaceans inferred from ribosomal DNA
2015
Cetaceans harbour a unique fauna of digeneans whose origin and relationships have sparked considerable debate during recent decades. Disparity in the species reported indicates that they do not share close affinities, but their unusual morphology has made their taxonomic identities and phylogenetic positions uncertain. Here we use sequence data to investigate the phylogenetic relationships of the main species of flukes infecting cetaceans. We sequenced the 18S, 28S and internal transcribed spacer 2 rDNA of digenean species representing all known families reported from cetaceans: Braunina cordiformis (Brauninidae), Ogmogaster antarcticus (Notocotylidae), Pholeter gastrophilus (Heterophyidae)…