The topography of multivariate normal mixtures

Multivariate normal mixtures provide a flexible method of fitting high-dimensional data. It is shown that their topography, in the sense of their key features as a density, can be analyzed rigorously in lower dimensions by use of a ridgeline manifold that contains all critical points, as well as the ridges of the density. A plot of the elevations on the ridgeline shows the key features of the mixed density. In addition, by use of the ridgeline, we uncover a function that determines the number of modes of the mixed density when there are two components being mixed. A followup analysis then gives a curvature function that can be used to prove a set of modality theorems.Comment: Published at http://dx.doi.org/10.1214/009053605000000417 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

The Clean Water Act, Water Quality, and Water Use

56 pages. Includes unsigned annotations by David Getches

Honor to the Dead of Dixie? Examining the Impetus and Enduring Devotion to the Confederate States of America and the Emblems that Commemorate the Failed Experiment of Governance in North America

A thesis presented to the faculty of the Caudill College of Arts, Humanities and Social Sciences at Morehead State University in partial fulfillment of the requirements for the Degree Master of Arts by Bruce Ray Greer on December 13, 2020

VALUATION OF CROP AND LIVESTOCK REPORTS: METHODOLOGICAL ISSUES AND QUESTIONS

Demand and Price Analysis,

State Regulation of Homeschooling and Homeschoolers’ SAT Scores

The professoriate is a highly individualized endeavor where scholars work independently on projects of their choosing. High stakes issues of retentions and promotions require new faculty members to document a public expertise in scholarship. In one sense, academics are scholarly gamesmen (Maccoby 1976) who attempt to create a scholarly presence while interpreting their colleagues’ patterns of actions and motivations. Such interpretations are created in an environment of “hollowed collegiality” (Massey, Wilger, and Colbeck, 1994) where superficial evidence of active participation often masquerades as community. For many new faculty members, connecting their work to a larger community of scholars can be an intimidating and lonely pursuit

Quadratic distances on probabilities: A unified foundation

This work builds a unified framework for the study of quadratic form distance measures as they are used in assessing the goodness of fit of models. Many important procedures have this structure, but the theory for these methods is dispersed and incomplete. Central to the statistical analysis of these distances is the spectral decomposition of the kernel that generates the distance. We show how this determines the limiting distribution of natural goodness-of-fit tests. Additionally, we develop a new notion, the spectral degrees of freedom of the test, based on this decomposition. The degrees of freedom are easy to compute and estimate, and can be used as a guide in the construction of useful procedures in this class.Comment: Published in at http://dx.doi.org/10.1214/009053607000000956 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Being backed by extended party networks can mean a greater chance of electoral success for a Congressional challenger

Political parties play a central role in democracies, helping to mediate between citizens and governing elites by running candidates for office who promise to pursue policy programs. But what if “the party” is really more of a collection of interest groups than a traditional party organization? Using data from US congressional elections and campaign finance, Bruce Desmarais, Ray La Raja and Mike Kowal show that parties are networks of partisan groups that converge on select groups of challengers. They explain that parties in the U.S. have become so distinctive and polarized, because they represent unique coalitions of policy demanders that influence the ideological composition of Congress

Riverbank Filtration Impacts on Post Disinfection Water Quality in Small Systems—A Case Study from Auburn and Nebraska City, Nebraska

Small water systems can experience a fluctuating quality of water in the distribution system after disinfection. As chlorine is the most common disinfectant for small systems, the occurrence of disinfection byproducts (DBPs) represents a common problem for these systems. Riverbank filtration (RBF) can be a valuable solution for small communities located on riverbanks. The objectives of this study were to evaluate (i) the improvements in water quality at two selected RBF systems, and (ii) the potential lower concentrations of DBPs, in particular, trihalomethanes (THMs), in small systems that use RBF. Two small communities in Nebraska, Auburn and Nebraska City, using RBF were selected. Results from this study highlight the ability of RBF systems to consistently improve the quality of the source water and reduce the occurrence of THMs in the distribution water. However, the relative removal of THMs was directly impacted by the dissolved organic carbon (DOC) removal. Different THM concentrations and different DOC removals were observed at the two RBF sites due to the different travel distances between the river and the extractions wells

Reviews

Brian Clegg, Mining The Internet — Information Gathering and Research on the Net, Kogan Page: London, 1999. ISBN: 0–7494–3025–7. Paperback, 147 pages, £9.99