We study a class M of cyclically presented groups that includes both finite and infinite groups and is defined by a certain combinatorial condition on the defining relations. This class includes many finite metacyclic generalized Fibonacci groups that have been previously identified in the literature. By analyzing their shift extensions...
We study a class of two-generator two-relator groups, denoted J[subscript n](m, k), that arise in the study of relative asphericity as groups satisfying a transitional curvature condition. Particular instances of these groups occur in the literature as finite groups of intriguing orders. Here we find infinite families of non-elementary virtually...
This research examines the independent and combined effects of drainage and imbibition flowrate on nonwetting phase capillary trapping in a two-phase, porous medium system. A uniform system of cubic arrangement and non-uniform systems of both cubic and rhombohedral arrangements were examined in order to analyze and compare the nonwetting phase...
Environmental education programs seek to foster an appreciation for the natural world while introducing students to scientific thinking. Citizen science engages non-scientists in the systematic collection and analysis of data. The Betts Forest Landscape Ecology Lab combines both goals by inviting teachers in Corvallis, Oregon, and surrounding areas to participate...
A group defined by a finite presentation with cyclic symmetry admits a shift automorphism that is periodic and word-length preserving. It is shown that if the presentation is combinatorially aspherical and orientable, in the sense that no relator is a cyclic permutation of the inverse of any of its shifts,...
From the earliest English colonization to the present day, there
has been interest in astronomy in this country. The purpose of this
thesis is to show how the science of astronomy developed in America
from the earliest observations by educated colonists using imported
instruments and publishing in European journals, to...
Ecologists have studied the responses of pelagic ecosystems
to varying levels of nutrient loading and fish predation on many
different scales ranging from small experimental enclosures to
whole lake systems. There are recurring patterns of response to
these two variables, which are generally predictable on the basis
of biogeographic, behavioral,...
The most abundant clone found in ribosomal RNA clone libraries obtained from the world's oceans belongs to the SAR11 phylogenetic group of environmental marine bacteria. Imaging and counting SAR11 bacterial cells in situ has been an important research objective for the past decade. This objective has been especially challenging due...