The ISOMAP nonlinear dimensionality reduction method of Tenenbaum, de Silva and Langford, was originally implemented in MATLAB by the developers of the algorithm. One of the issues involved with ISOMAP is the need to determine the number of reduced dimensions that best represents the original data. For this purpose, Tenenbaum, de Silva and Langford provide a plot similar to the scree plot in pr...

We present results from an archival study of 70 medium-redshift QSOs observed with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. The QSOs have magnitudes MV ≤ −23 (total nuclear plus host light) and redshifts 0.06 ≤ z ≤ 0.46. A close relationship between QSO host and nucleus is found by examining multiple parameters at once. A principal components analysis shows that 3 ...

Pearl millet (Pennisetum glaucum (L.) R. Br.) and napier grass (Pennisetum purpureum Schumach) are the most economically important species in the genus Pennisetum. Knowledge of genetic diversity of these two species would enhance their potentials for utilization. The present work assessed the genetic diversity and phylogenetic relationship among Nigerian and Indian accessions of pearl millet an...

Bioinformatics sample summaries often involve distances or the conversion of similarities to dissimilarities, while Procrustes methods can proceed either via distances or via the shape coordinates underlying those distances. There is a distance–distance statistical method, currently increasing in popularity in some of my applications domains, that is at once simple, intuitive, and quite wronghe...

The use of next-generation sequencing technologies is revolutionizing microbial ecology by allowing a deep phylogenetic coverage of tens to thousands of samples simultaneously. Double Principal Coordinates Analysis (DPCoA) is a multivariate method, developed in community ecology, able to integrate a distance matrix describing differences among species (e.g. phylogenetic distances) in the analys...

university of tehran administers a test known as the university of tehran english proficiency test (the utept) to phd candidates on a yearly basis. by definition, the test can be considered a high-stakes one. the validity of high stakes tests needs to be known (roever, 2001). as mesick (1988) maintains, if the validity of high stakes tests are not known, it might have some undesirable consequen...

We present the final results from the Arecibo Observatory OH megamaser survey. We discuss in detail the properties of the remaining 18 OH megamasers detected in the survey, including 3 redetections. We place upper limits on the OH emission from 85 nondetections and examine the properties of 25 ambiguous cases for which the presence or absence of OH emission could not be determined. The complete...

A method for time series analysis of molecular dynamics simulation of a protein is presented. In this approach, wavelet analysis and principal component analysis are combined to decompose the spatio-temporal protein dynamics into contributions from a hierarchy of different time and space scales. Unlike the conventional Fourier-based approaches, the time-localized wavelet basis captures the vibr...