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Full-Text Articles in Physical Sciences and Mathematics

Spatial Ecology Of The Coachwhip, Masticophis Flagellum (Squamata: Colubridae), In Eastern Texas, Richard W. Johnson, Robert R. Fleet, Michael B. Keck, D. Craig Rudolph Jan 2007

Spatial Ecology Of The Coachwhip, Masticophis Flagellum (Squamata: Colubridae), In Eastern Texas, Richard W. Johnson, Robert R. Fleet, Michael B. Keck, D. Craig Rudolph

Faculty Publications

We radio-tracked nine Masticophis flagellum (Coachwhips) to determine home range, habitat use, and movements in eastern Texas from April to October 2000. Home ranges of Coachwhips contained more oak savanna macrohabitat than early-successional pine plantation or forested seep, based on the availability of these three macrohabitats in the study area. Likewise, within their individual home ranges, Coachwhips used oak savanna more than the other two macrohabitats, based on availability. An analysis of microhabitat use revealed that, relative to random sites within their home range, Coachwhips were found at sites with fewer pine trees and more herbaceous vegetation taller than 30 …


Covering Properties And Cohen Forcing, Akira Iwasa Jan 2007

Covering Properties And Cohen Forcing, Akira Iwasa

Faculty Publications

We will show that adding Cohen reals preserves the covering property that every open cover has a σ-P Q refinement and deduce that adding Cohen reals preserves covering properties such as paracompactness, subparacompactness and screenability.


Multiple Mixed-Type Attractors In A Competition Model, J. M. Cushing, Shandelle M. Henson, Chantel C. Blackburn Jan 2007

Multiple Mixed-Type Attractors In A Competition Model, J. M. Cushing, Shandelle M. Henson, Chantel C. Blackburn

Faculty Publications

We show that a discrete-time, two-species competition model with Ricker (exponential) nonlinearities can exhibit multiple mixed-type attractors. By this is meant dynamic scenarios in which there are simultaneously present both coexistence attractors (in which both species are present) and exclusion attractors (in which one species is absent). Recent studies have investigated the inclusion of life-cycle stages in competition models as a casual mechanism for the existence of these kinds of multiple attractors. In this paper we investigate the role of nonlinearities in competition models without life-cycle stages. © 2007 Taylor & Francis Group, LLC.