منابع مشابه
Measures of stratigraphic fit to phylogeny and their sensitivity to tree size, tree shape, and scale
Measures of stratigraphic fit to phylogeny are analyzed to test how they are affected by the shape and size of the phylogenetic trees and by the number of stratigraphic intervals encompassed. Monte Carlo randomizations are used to investigate the sensitivity of three commonly used measures (SCI, GER and MSM*) approximating their distribution of possible values under certain conditions. All are ...
متن کاملPetrology and Stratigraphic Setting
anomolously low A1203, low Ti02 and are enriched in chromium and nick~A We present petrographic and chemical c ata on the Kamloops Lake picritic tmalts as we1 I as the stratigraphic setting for thwe ultramafic lavas. Age constraints derive From field relationships, Mineral chemistry indicates th 31 these ultramafic rocks represent mantle-deri.ed material which has undergone: minimal differentia...
متن کاملOn B-Tree Indices for Skewed Distributions
It is often the case that the set of values over which a B-Tree is constructed has a skewed distribution. We present a geometric growth technique to manage postings records in such cases, and show that the performance of such a technique is better than that of a straightforward fixed length postings list: It guarantees 1 disk access on searching, and it takes a fraction of the space that its co...
متن کاملStratigraphic and Structural Setting
mapping of a I5 square kilometre area around Jock Creek and detailed (1:lOOO) mapping of the mineralized area were carried out in 1988 and 1989. Marsden and Moore (1989) give an account of the geology outlined by mapping during the 1988 field season. This report presents some additions and revisions to that stratigraphy, integrates field observations with petrographic work and literature rese...
متن کاملA Decision - Tree Model of Balance
We present an alternative model of human cognitive development on the balance scale task. Study of this task has inspired a wide range of human and computational work. The task requires that children predict the outcome of placing a discrete number of weights at various distances on either side of a fulcrum. Our model, which features the symbolic learning algorithm C4.5 as a transition mechanis...
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ژورنال
عنوان ژورنال: Systematic Biology
سال: 1997
ISSN: 1063-5157
DOI: 10.2307/2413697