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Likelihood Criteria (likelihood + criterion)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

On the distribution of wildfire sizes

ENVIRONMETRICS, Issue 6 2003
Frederic Paik Schoenberg
Abstract A variety of models for the wildfire size distribution are examined using data on Los Angeles County wildfires greater than 100 acres between 1950 and 2000. In addition to graphs and likelihood criteria, Kolmogorov,Smirnoff and Cramer,von Mises statistics are used to compare the models. The tapered Pareto distribution appears to fit the data quite well and offers some advantages over the untapered Pareto distribution, while alternatives including the lognormal, half-normal, exponential and extremal distributions fit poorly. The size distribution appears to be quite stable over the examination period, though inspection of the transformed wildfire sizes for the tapered Pareto reveals some limited trend in the residuals, indicating a very slight gradual decrease in the average fire size in Los Angeles County over these 50 years. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Phylogenetic study on Shiraia bambusicola by rDNA sequence analyses

JOURNAL OF BASIC MICROBIOLOGY, Issue 5 2004
Tian-Fan Cheng
In this study, 18S rDNA and ITS-5.8S rDNA regions of four Shiraia bambusicola isolates collected from different species of bamboos were amplified by PCR with universal primer pairs NS1/NS8 and ITS5/ITS4, respectively, and sequenced. Phylogenetic analyses were conducted on three selected datasets of rDNA sequences. Maximum parsimony, distance and maximum likelihood criteria were used to infer trees. Morphological characteristics were also observed. The positioning of Shiraia in the order Pleosporales was well supported by bootstrap, which agreed with the placement by Amano (1980) according to their morphology. We did not find significant inter-hostal differences among these four isolates from different species of bamboos. From the results of analyses and comparison of their rDNA sequences, we conclude that Shiraia should be classified into Pleosporales as Amano (1980) proposed and suggest that it might be positioned in the family Phaeosphaeriaceae. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

PHYLOGENETIC SYSTEMATICS OF THE ULVACEAE (ULVALES, ULVOPHYCEAE) USING CHLOROPLAST AND NUCLEAR DNA SEQUENCES,

JOURNAL OF PHYCOLOGY, Issue 6 2002
Hillary S. Hayden
Systematic hypotheses for the Ulvaceae were tested using phylogenetic analysis of sequences for the gene encoding the large subunit of RUBISCO, small subunit rDNA and a combined data matrix. Representatives of eight putative ulvaceous genera and twelve additional taxa from the Ulvophyceae and Trebouxiophyceae were included in analyses using maximum parsimony and maximum likelihood criteria. Molecular data supported hypotheses for the Ulvaceae that are based on the early development of vegetative thalli and motile cell ultrastructure. Ulvaceae sensu Floyd and O'Kelly, including Percursaria Bory de Saint-Vincent, Ulvaria Ruprecht and a complex of closely related species of Chloropelta Tanner, Enteromorpha Link and Ulva L. was supported; however, monophyly of Enteromorpha and Ulva was not supported. The Ulvales and Ulotrichales sensu Floyd and O'Kelly were monophyletic. Blidingia Kylin and Kornmannia Bliding were allied with the former and Capsosiphon Gobi with the latter, although relationships among these and other taxa in these orders remain uncertain. The Ulvales are characterized by an isomorphic life history pattern, gametangia and sporangia that are identical in structure and development, motile cells with bilobed terminal caps and proximal sheaths consisting of two equal subunits. Method of motile cell release and the gross morphology of vegetative thalli are not systematically reliable characters. [source]

Molecular systematics of cowries (Gastropoda: Cypraeidae) and diversification patterns in the tropics

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2003
CHRISTOPHER P. MEYER
This study produces a nearly comprehensive phylogeny for the marine gastropod group Cypraeidae (cowries) and uses this topology to examine diversification patterns in the tropics. The dataset is based on molecular sequence data from two mitochondrial genes and includes 210 evolutionary significant units (ESUs) from 170 recognized species (>80%). Systematics for the group is revised based on well-supported clades, and tree topology is generally consistent with previously proposed classification schemes. Three new genera are introduced (Cryptocypraea gen. nov, Palmulacypraea gen. nov, and Contradusta gen. nov) and two previous genera are resurrected (Perisserosa and Eclogavena). One new tribe is proposed (Bistolidini). Topologies produced by a range of transition:transversion (Ti:Tv) weighting schemes in parsimony are pooled and evaluated using maximum likelihood criteria. Extensive geographical coverage shows persistent, large-scale geographical structure in sister-groups. Genetic divergence between subspecies is often equivalent or even greater than that between recognized species. Using ESUs as a metric, diversity throughout the Indo-West Pacific (IWP) increases by 38%. Intra- and inter-regional diversification patterns show that the IWP is the centre for speciation in cowries. The other major tropical regions of the world are inhabited by a predominantly relictual fauna; from a cowrie's eye-view. Good dispersal ability begets larger ranges, increased extinction resistance and morphological stasis; whereas shorter larval duration results in smaller ranges, higher speciation rates, but also higher turnover. Larval duration and dispersal ability appear correlated with ocean productivity as taxa with longer-lived larvae are associated with oligotrophic conditions; whereas taxa with shorter larval durations are associated with eutrophic, continental conditions. This tendency is carried to the extreme in temperate or upwelling regions where a planktonic phase is completely lost and crawl-away larvae evolve multiple times. A strong phylogenetic trend supports these observations as lineages leading up to and including the derived Indo-West Pacific Erroneinae clade contain taxa predominantly restricted to continental habitats and have undergone the greatest evolutionary radiations in their respective regions. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 79, 401, 459. [source]