Search results for "Tree"
showing 10 items of 1841 documents
Suffix array and Lyndon factorization of a text
2014
Abstract The main goal of this paper is to highlight the relationship between the suffix array of a text and its Lyndon factorization. It is proved in [15] that one can obtain the Lyndon factorization of a text from its suffix array. Conversely, here we show a new method for constructing the suffix array of a text that takes advantage of its Lyndon factorization. The surprising consequence of our results is that, in order to construct the suffix array, the local suffixes inside each Lyndon factor can be separately processed, allowing different implementative scenarios, such as online, external and internal memory, or parallel implementations. Based on our results, the algorithm that we prop…
Routing Algorithm for Maximizing Lifetime of Wireless Sensor Network for Broadcast Transmission
2018
In the article we discuss solutions of the maximum lifetime broadcasting problem in wireless sensor networks. Due to limited energy resources of the network nodes to find an optimal transmission route of the broadcasted data we minimize the maximum energy consumed by the nodes. We give an analytical solution of the problem in one dimensional regular sensor network for the point-to-point and point-to-multipoint data transmission scheme. We show that in such a network, when the cost of data transmission is a polynomial function of distance between transmitter and receiver, there exist solutions with an equal energy, i.e., all nodes of the network consume the same amount of energy. We assume t…
Topology of correlation-based minimal spanning trees in real and model markets
2003
We present here a topological characterization of the minimal spanning tree that can be obtained by considering the price return correlations of stocks traded in a financial market. We compare the minimal spanning tree obtained from a large group of stocks traded at the New York Stock Exchange during a 12-year trading period with the one obtained from surrogated data simulated by using simple market models. We find that the empirical tree has features of a complex network that cannot be reproduced, even as a first approximation, by a random market model and by the one-factor model.
Biodiversity dynamics and their driving factors during the Cretaceous diversification of Spatangoida (Echinoidea, Echinodermata)
2004
Abstract Variations in recorded diversity over time present a scrambled signal that is modulated by a large number of variables: the potential of particular life forms to generate evolutionary innovations, external constraints induced by the environment in its broad sense, the heterogeneity of the fossil record and the analytical artefacts due to sampling bias. A key question is how to characterise and quantify the separate input of any given factor in the overall diversity signal. This paper explores the structure of diversity data for spatangoid heart urchins and the sensitivity of recorded diversity to different factors of analytical bias (length of geological periods, proportion of pala…
Phylogeny and morphology of Anthracoidea pamiroalaica sp. nov. infecting the endemic sedge Carex koshewnikowii in the Pamir Alai Mts (Tajikistan)
2015
A novel Anthracoidea species, A. pamiroalaica on the endemic sedge Carex koshewnikowii, is described and illustrated from the Pamir Alai Mts in Tajikistan (Central Asia). The new species is phenotypically nearly identical with Anthracoidea sempervirentis, but clearly divergent genetically. Phylogenetic analyses based on LSU sequences showed affinity of Anthracoidea pamiroalaica to A. baldensis, A. rupestris, A. capillaris, and A. vankyi infecting host sedges in different Carex sections (Baldenses, Rupestres, Chlorostachyae, and Phaestoglochin, respectively), but not to A. misandrae, and A. sempervirentis, two sequenced species parasitic on host species from the section Aulocystis. This phyl…
Phylogenetic analysis of cryptic speciation in the polychaetePygospio elegans
2012
Development in marine invertebrate species can take place through a variety of modes and larval forms, but within a species, developmental mode is typically uniform. Poecilogony refers to the presence of more than one mode of development within a single species. True poecilogony is rare, however, and in some cases, apparent poecilogony is actually the result of variation in development mode among recently diverged cryptic species. We used a phylogenetic approach to examine whether poecilogony in the marine polychaete worm, Pygospio elegans, is the result of cryptic speciation. Populations of worms identified as P. elegans express a variety of developmental modes including planktonic, broode…
Morphologically similar but not closely related: the long-spored species of Subulicystidium (Trechisporales, Basidiomycota)
2020
AbstractSpecies boundaries and geographic distribution of corticioid fungi (resupinate Basidiomycota) are often poorly known. Our recent study on Subulicystidium showed that species diversity in this genus is at least twice as high as previously recognized. This re-estimation of the species diversity was based on a study of only a part of the genus. The present study sheds light on molecular and morphological diversity of three more species. We generated 27 ITS and 24 28S nuclear ribosomal DNA sequences from 49 specimens labelled as Subulicystidium cochleum, S. longisporum and S. perlongisporum and collected in distant geographic localities. We assessed pairwise dissimilarities and phylogen…
Molecular Evolution and the Phylogenetic Relationships of the African Toad, Bufo danielae PERRET, 1977 (Salientia : Bufonidae)
1980
Abstract Phylogenetic relationships of the African toad Bufo danielae are investigated using a variety of biochemical approaches. Nuclear DNA content was assayed and compared to representatives of three species groups of African Bufo. Cellogel electrophoresis of plasma proteins was performed and patterns of B. danielae compared with those of representatives of the African B. regularis species complex. Finally microcomplement fixation analyses of albumin relationships of B. danielae and African Bufo were carried out. The strengths of the varied approaches for phylogenetic analysis are discussed. B. danielae appears most closely related to B. maculatus and B. pusillus, it being some 5-6 mill…
Salicornia L. (Amaranthaceae) in South Africa and Namibia: rapid spread and ecological diversification of cryptic species
2013
In Salicornia, morphology does not provide reliable diagnostic characters supporting the true extent of evolutionary divergence in the genus, and species concepts have been challenged by molecular analyses. Here, we report the results of an analysis of 91 accessions of the S. meyeriana complex from South Africa and Namibia using the measurements of 38 morphological traits and external transcribed spacer (ETS) sequence data. Morphological data were analysed using discriminant analysis, principal coordinate analysis and nonmetric multidimensional scaling. Phylogenetic divergence was compared with the geographical and ecological diversity of the sampled populations. Tree topology corresponds t…
New insights into the taxonomy and phylogeny of social voles inferred from mitochondrial cytochrome b sequences
2012
We sequenced the entire cytochrome b gene in Microtus paradoxus from Turkmenistan and Microtus socialis from Crimea and Kalmykia. Phylogenetic relationships among social voles were reconstructed by the inclusion into analyses of a further 23 published haplotypes belonging to six species. The two probabilistic methods which were used in phylogenetic analyses, the Bayesian inference and Maximum Likelihood, yielded very similar results. Both trees showed two highly divergent lineages which were further subdivided into seven species. The socialis lineage encompassed four species (M. socialis, M. irani, M. anatolicus, and M. paradoxus), and the remaining three species clustered into the guenther…