L. Vigilant et al. [1] recently presented "the strongest support yet for the placement of [their] common mtDNA [mitochondrial DNA] ancestor in Africa some 200,000 years ago." This support stems from a tree estimated by maximum parsimony from mtDNA sequence data with the use of the computer program PAUP [2]. The African origin is inferred from this tree because (i) the most basal splits are amon...

PSODA is a comprehensive phylogenetics package, including alignment, phylogenetic search under both parsimony and maximum likelihood, and visualisation and analysis tools. PSODA offers performance comparable to PAUP* in an open source package that aims to provide a foundation for researchers examining new phylogenetic algorithms. A key new feature is PsodaScript, an extension to the nearly ubiq...

A new genus and species of captorhinid reptile from the Lower PermianWaggoner Ranch formation of northcentral Texas, Reiszorhinus olsoni, is described on the basis of well-preserved cranial material. The holotypic specimen, consisting of a partial skull and mandible, was misidentified by S. W.Williston in 1917 asLabidosaurus hamatus. Autapomorphies of the new taxon include recurved teeth and th...

A phylogenetic tree is a graphical representation of the evolutionary relationship between taxonomic groups. The term phylogeny refers to the evolution or historical development of a plant or animal species, or even a human tribe or similar group. In order to make ourself to understand the structure of phylogenetic tree. We present a spring-embedder model for drawing rooted and unrooted phyloge...

OBJECTIVES Many drug and fluid regimens in emergency medicine are weight dependent in adults, but no standard adult weight estimation tools exist. Paediatric weight is often estimated in emergency situations using methods based on age or height when direct measurement is not possible, and recently, methods based on mid-arm circumference (MAC) have also been developed. The aim of this study was ...