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Differences In Quality Of Care By Insurance Plan: A Fee-For-Service Vs. Health Maintenance Organization Comparison, Pamela Driggers Silcox

Doctoral Dissertations

The history of health insurance in the United States has perpetuated and enabled a health care industry that has been rewarded for increased spending rather than cost control. With the original plan setting no spending limit on health care providers, fee-for service reimbursement provided greater incentive to spend than to contain costs. Attempts to control the soaring costs of health care services have given rise to managed care insurance plans that base reimbursement on health outcome data. Given that the birth of managed care includes stringent reimbursement guidelines and ensuing controversy over services provided or not provided, this study sought …

A Qualitative Investigation Of Polish Consumers’ Retail Experiences During The Transitional Period: 1989-2001, Heesun Seo

Doctoral Dissertations

The general objective of this dissertation is to investigate the most current phenomenon in the Polish retail environment and the recent Polish consumers’ retail experience. Specifically, by examining information search behavior, shopping behavior, and post-purchase behavior, themes emerged in terms of how the changes in the retail environment influenced the patronage and consumption behavior of Polish consumers. An exploratory research approach is used to conduct this research due to the lack of existing knowledge on Polish consumers and the ever-changing nature of the market environment in Poland. Moreover, qualitative research method with naturalistic inquiry was used to present the Polish …

Habitat Use, Distribution And Conservation Status Of The Mikado Pheasant (Syrmaticus Mikado) In Taiwan, Cara Lin Bridgman

Doctoral Dissertations

To evaluate the conservation status of Taiwan’s mikado pheasant, Syrmaticus mikado (Phasianidae), I test the similarity of preferred habitat to primary and secondary forest, develop models of habitat availability within Taiwan, and examine population trends within two locations inside Yushan National Park. The characteristics of locations with pheasant activity were most similar to secondary forest: high shrub stem counts and low canopy and leaf litter coverage. None of these variables were applicable to geographic informationsystems analysis. To the known extent of range and area of occupancy, I compared a model based on the habitats described in field guides. This model …

Using Remote Sensing And Geographic Information Systems To Define Conservation Priorities, Clinton N. Jenkins

Doctoral Dissertations

This dissertation discusses several techniques of combining ecology and technology, specifically satellite images and geographic information systems, to define conservation priorities and answer conservation questions. They include single species approaches (chapters 2 and 3), global approaches (chapter 4), and regional approaches (chapters 5 and 6).

Chapters 2 and 3 concern the Cape Sable Seaside Sparrow (Ammodramus mirabilis maritimus). This sparrow, and its habitat, is legally protected under the United States Endangered Species Act. Chapter 2 quantitatively demonstrates that poor water management is threatening the habitat of this sparrow and by consequence its survival. Chapter 3 describes formal testing …

Colonization History And Alternative Community States In Experimental Microcosms, Craig Richard Zimmermann

Doctoral Dissertations

Using s suite of disparate experimental systems, three tests of the effect of variation in community history on community states were performed. The first test explored the effect of species invasion order on the structure and invasibility in soil microbial communities. Microcosm communities were assembled by augmenting an existing soil community with sequential introductions of three bacterial strains under three alternative sequences. Assembled communities were then probed with a genetically engineered bioremediative bacterium to test the relative vulnerability of these communities to this strain. Results indicated that variation in invasion order resulted in the production of alternative community states with …

Inbreeding, Male Diploidy, And Complementary Sex Determination In The Solitary Wasp Euodynerus Foraminatus, Julie Kozaczka Stahlhut

Dissertations

In the insect order Hymenoptera, which includes wasps, bees, and ants, females normally develop from fertilized eggs and are diploid, while males develop from unfertilized eggs and are haploid. Underlying mechanisms of sex determination are more complex and vary among different hymenopteran taxa. One such method is single-locus complementary sex determination, or sl-CSD, in which sex is determined by a single gene locus with many alleles. In species with sl-CSD, diploid individuals that are heterozygous at the sex locus develop as normal females and hemizygous (haploid) individuals as normal males, but diploids homozygous at the sex locus will also develop …

Modeling The Role Of No-Take Marine Reserves In Fisheries Management, Deidre F. Gilbert

Electronic Theses and Dissertations

In recent years there has been increasing interest in the potential of no-take marine reserves to benefit fisheries management. Scientific reviews have shown that reserves often lead to substantial increases in the density, biomass, size and diversity of marine fishes inside their boundaries. However, little empirical work has been done to determine the effect of reserves on the fisheries outside their boundaries, such as potential changes in yield, size of fleet, or variability in catch. In order to explore the interaction between the biological growth and dispersion processes of the harvested stock and the changing economic incentives of harvesters created …

Satellite-Measured Chlorophyll Variability Within The Upwelling Zone Near Heceta Bank, Oregon, Jennifer Bosch

Electronic Theses and Dissertations

Heceta Bank, a unique shallow bank on the southern Oregon shelf, is located within the California Current upwelling system. Four years (1998-2001) of 1-km resolution SeaWiFS ocean color satellite data of the Oregon coast are used to provide the first systematic description, and quantification of seasonal and interannual surface chlorophyll variability in the Heceta Bank region of coastal Oregon. The variability over the bank is examined with respect to wind forcing and surface temperature, and compared to the variability observed in topographically simpler shelf regions north and south of the bank. A seasonal cycle with lowest concentrations in the fall …

Time Series Analysis Of Bat Ultrasound Signals, Xu Cui

Masters Theses

The general objectives of this study are to develop new methods to analyze ultrasound signals recorded during field observations of bats, and relate these to bat biology. In particular, I investigate methods to determine whether or not sound pulses produced by multiple bats are independent of each other when the bats are searching for food in the same environment. Four models are proposed to explain the time series of recorded signals and it is found that the Poisson model, which assumes pulses are independent, fits the data best. A computer program, BatCount was developed as part of this study, to …

Recruitment Variability Of Atlantic Croaker, Micropogonia Undulatus, With Observations On Environmental Factors, Sumalee Hoskin

Biological Sciences Theses & Dissertations

I examined entrance patterns of Atlantic croaker, Micropogonias undulatus by comparing the abundance, length, age and growth rates, of larvae as they entered Oregon and Ocracoke Inlets, NC. These biological factors were then compared against environmental factors to assess the influence the physical environment has on recruitment variability. Entrance abundance into Oregon Inlet was an order of magnitude higher than abundance into Ocracoke Inlet. However, the difference was influenced by three peak events in Oregon Inlet and non-parametric tests found no difference in median abundance between the two inlets. Mean standard length was smaller at Oregon Inlet than Ocracoke Inlet …

The Effect Of A Predator Gradient On Female Oviposition Site Selection And Larval Performance, Josef F. Rieger

Biological Sciences Theses & Dissertations

Patterns of larval amphibian distribution and abundance have historically been ascribed to direct predation. However, adult oviposition site selection is an alternative mechanism that can produce identical patterns and significantly influence community assembly. Although such behavioral habitat selection has been documented in several amphibian species whose larvae lack particular anti-predator defenses, the sensitivity of adult amphibians in detecting predator cues and avoiding these habitats has not yet been determined. If larval survivorship is greatly reduced in sites containing predatory fish, selection to detect and avoid habitats with low fish densities should be strong. I conducted three experiments which, (1) evaluated …

A Pilot Study To Test Ventless Traps As A Means To Quantify Populations Of The American Lobster (Homarus Americanus), Carin Louise Poeschel

Electronic Theses and Dissertations

The American lobster, Homarus americanus, is Maine's most valuable marine fishery. The state of Maine has an economic interest in the protection of this resource. The health of this industry depends on effective management for sustainability. However, there is little quantitative information on American lobsters less than harvestable size. A study was conducted to evaluate the utility of traps modified to catch sublegal lobsters. With the aid of fishernlen fiom six of the eight Maine coastal counties over a four-month time period (July through October, 2000), data were recorded to compare catch rates in experimental traps with no escape vents …

An Ecosystem Dynamics Model Of Monterey Bay, California, Lawrence S. Klein

Electronic Theses and Dissertations

Monterey Bay is an upwelling region with high biological productivity in the California Coastal Current System. Several moorings, developed and maintained by the Monterey Bay Aquarium Research Institute (MBARI), have produced a long-term, highquality time series oceanographic data set for the Monterey Bay. The data set has revealed a more comprehensive picture of physical-biological interaction on seasonal and interannual variability. To improve our understanding of how the marine ecosystem responds to physical forcing, especially upwelling, an open ocean ecosystem model was modified for the Monterey Bay upwelling region. The result was a nine-component ecosystem model of Monterey Bay, which produced …

An Assessment Of Methods For Testing The Reliability Of Wildlife Occurrence Models Used In Gap Analysis, Sandra M. Schaefer

Electronic Theses and Dissertations

Habitat association models designed to predict species occurrence are often tested by comparing predictions to field observations. Two types of error are then reported, omission (Yo of species not predicted but present on a site) and commission (% of species predicted but not present on a site). The purpose of this research was to assess the Maine Gap Analysis vertebrate predictions using the traditional site-specific approach and to determine what factors influence the amounts of error reported. I also developed a species-specific approach for testing the accuracy of the vertebrate predictions and compared these results to the site-specific method. When …

Systematics Of Northeastern Meadow Vole (Microtus Pennsylvanicus) Subspecies, With Empasis On The Island Endemic (M. P. Shattucki, Howe 1901) In Penobscot Bay, Maine, Jennifer Marie Lowry

Electronic Theses and Dissertations

The Penobscot meadow vole (Microtus pennsylvanicus shattucki) (PMV) is an insular subspecies of meadow vole (M. pennsylvanicus) inhabiting the islands of North Haven, Islesboro, and Tumbledown Dick in Penobscot Bay, Maine. It is one in a suite of island meadow vole subspecies which has been described from southern New England through eastern Canada. The subspecific recognition of M. p. shattucki, along with the others in this group, was solely based on a univariate analysis of a few morphological characters, which has fostered debate about the validity of the subspecies. Despite this uncertainty, the taxonomy is …

Using A Geographical Information System Approach To Assess Sea Ice Impacts On A Productive Benthic System In The Northern Bering Sea, Jaclyn Leigh Clement

Masters Theses

Physical, hydrochemical, and biological data were collected during three research cruises from winter through spring in the northern Bering Sea. In addition, seasonal ice cover data were used to evaluate the relationship between ice and specific biological processes. Ice-water-biotic interactions were investigated and possible relationships defined. Data collected during late winter indicate low levels of water column production and benthic respiration. However, spring measurements made during and just after icemelt indicate a time of high water column production and benthic respiration. Interannual variation in the spatial and temporal distribution of sea ice affects the timing of seasonal processes, particularly the …

Genesis And Morphology Of Soil Pendants In Quaternary Landforms Of Pahranagat Valley, Nevada, Amy Lynn Brock

UNLV Theses, Dissertations, Professional Papers, and Capstones

Five geomorphic surfaces present in the northern Pahranagat Valley, Lincoln County, Nevada range in age from Early Pleistocene to Recent (Q1-Q5) and vary in clast lithology from dolomite to volcanic tephras. Two chronosequences and 5 lithosequences were compared to evaluate micro and macromorphic characteristics and development of soil pendants. This study presents a new interpretation for soil pendant development. Key features observed in the Pahranagat Valley pendants provide evidence for precipitation at the clast-pendant contact suggesting that newer deposits are not always found at the pendant terminus as other studies have assumed. These features include a void at the clast-pendant …

Fine Root Vitality And Its Application In A Minirhizotron Study Of A Co2 Enrichment In A Florida Scrub Oak Ecosystem, Brandon Todd Herbert

Biological Sciences Theses & Dissertations

Minirhizotron images are assigned color codes to approximate the age of individual roots in situ. Triphenyl-tetrazolium chloride (TTC) has been used to measure the vitality of plant tissue by detecting dehydrogenase activity. TTC was used to assess the vitality of root tissue by color in a scrub oak ecosystem at Kennedy Space Center in central Florida. Roots were excavated, sorted into four color classes and stained with TTC. The product of the reduction of TTC by dehydrogenase enzyme, formazan, was extracted and its absorbance recorded using a spectrophotometer. A significant difference (p2 enrichment being conducted on a scrub oak …

Long Term Residual Effects Of A Nutrient Addition On A Barrier Island Dune Ecosystem, Susan M. Heyel

Biological Sciences Theses & Dissertations

In 1991, 150 m² were fertilized with nitrogen on three dunes on Hog Island, part of the Virginia Coast Reserve Long Term Ecological Research site, to examine plant community response to nitrogen addition. In 2000, the fertilized plots continued to exhibit a positive growth response. This study sampled the aboveground biomass, belowground biomass, and nutrient content of the experimental plots to examine the long- term patterns of nitrogen retention in a nitrogen limited system. Aboveground and belowground biomass was significantly greater in the fertilized plots than in the control plots. Aboveground biomass exhibited was significantly greater in control and …

Interactions Among Introduced Ungulates, Plants, And Pollinators: A Field Study In The Temperate Forest Of The Southern Andes, Diego P. Vazquez

Doctoral Dissertations

Introduced mammalian herbivores can significantly affect ecosystems. I studied the effects of introduced ungulates on plant-pollinator interactions in the temperate forest of the southern Andes. Introduced mammalian herbivores, including ungulates, are a major conservation problem in this biome. I conducted field studies in eight forested sites where Nothofagus dombeyii was the dominant canopy tree. I described the interactions between fifteen common, insect-pollinated understory plants. I used these data to address two main questions. The first one is whether the susceptibility of plants and pollinators to disturbance by introduced ungulates is related to their degree of interaction specialization and interaction asymmetry. …

The Effects Of Soy Protein On Bone Mineral Density On Ovariectomized Rats, Mary C. May

Honors Theses

No abstract provided.

Coyote Foraging Ecology, Vigilance, And Behavioral Cascades In Response To Gray Wolf Reintroduction In Yellowstone National Park, T. Adam Switalski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Vigilance behavior can aid in the detection of predators and may also play a role in observation of conspecifics, in food acquisition, and in the prevention of kleptoparasitism. However, in most occasions, vigilance is most important as an antipredator function. Generally, factors that increase the risk of predation also increase the amount of vigilance. We examined whether the reintroduction of the large predator, the wolf, in Yellowstone National Park (YNP) would influence coyote vigilance and foraging ecology. From December 1997 to July 2000, we collected 1743 h of coyote activity budgets. Coyote home ranges occurred within wolf territories (termed high-use …

Application Of Biophysical Data To An Unsupervised Classification To Map Ecoregional Boundaries In The Desert Southwest, Paxton R. Mcclurg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An unsupervised classification was applied to continuous biophysical variables in an attempt to delineate ecoregional boundaries in the desert southwest. Output was then compared with ecoregions delineated by the Natural Resources Conservation Service (NRCS), the Environmental Protection Agency (EPA), and the Forest Service at the national level. An attempt was made to use the same biophysical variables for input into the unsupervised classification as was emphasized by the various agencies with their ecoregional classifications at the desert level. Major constraints included data availability at such a large study area, data resolution, and data that were continuous. This eliminated categorical data …

The Role Of Brown Bears (Ursus Arctos) In Nutrient Transport Into Forests Near A Salmon Stream In Coastal British Columbia, Canada, Arthur Morris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nutrients from spawned salmon contribute to the fertility of rivers and riparian areas. Adjacent forests, even far from rivers, could receive substantial amounts of nitrogen and other nutrients from salmon. Since brown bears feed heavily on spawning salmon, bears probably influence the movement of nutrients from salmon into surrounding forests. Because salmon-derived nitrogen is high in ¹⁵N, increased isotopic enrichment is expected in forest soils and vegetation if this transport is occurring. Based on relative ¹⁵N enrichment of spawning areas, a quantitative estimate of marine-derived nitrogen (MDN) can be obtained using a linear two-source mixing model. To evaluate …

Marine Protected Areas In The Gulf Of Maine: Policy For A Common Resource, Carolyn F. Skinder

Electronic Theses and Dissertations

In the wake of 25 years of unsuccessful single-fisheries management in the Gulf of Maine, there has been growing support for reform. Ecosystem management has been proposed as one alternative, but the information needed to manage whole ecosystems is greatly lacking. Implementing fully-protected marine protected areas (MPAs) is one way to preserve habitat while at the same time acquiring data for future ecosystem management. Under the current institutional arrangement in the Gulf, engineering agreement for MPAs is difficult due to the differing goals of varied user groups. The situation is reflective of a common property resource problem in that there …

Roosting Ecology Of The Grey-Headed Flying Fox: Spatial Dispersion In A Summer Camp, Jennifer L. Holmes

Masters Theses

A colony of Grey-headed flying foxes (Pteropus poliocephalus) in the Royal Botanic Gardens in Sydney, Australia was studied over a ten-week period before, during and after the mating season to assess spatial distribution of individuals, specifically investigating age and sex segregation. Ground censusing techniques were used to determine weekly estimates of the numbers of bats in the colony and numbers of bats within each tree. Surveys were used to document sexes and ages of bats occupying each tree. Unlike Nelson’s (1965) findings, the social structure of the colony was based not on mating strategies of individual bats but …

Anting Behavior In Birds: Ant Selection And Effect Of Ant Chemistry On Feather Ectoparasites, Hannah Carrington Revis

Biological Sciences Theses & Dissertations

Active anting behavior occurs when songbirds apply ants to their feathers. During anting displays, a bird draws its wings forward in front of the head and swings its tail around to the far right or left. Both wing and tail feathers are then rubbed with ants held in the bird's beak. The potential associations among ants, feather ectoparasites and birds make anting behavior an important community-level interaction. Although this behavior is cosmopolitan in distribution and occurs in a wide variety of passerine birds, it remains poorly understood. This dissertation tested hypotheses about anting behavior through controlled experiments with captive songbirds …

Summer Vertical Phytoplankton Distribution In The Lower Chesapeake Bay, Mollie Jill Weinstein

Biological Sciences Theses & Dissertations

Autotrophic picoplankton and phytoplankton composite samples were collected from the surface, pycnocline, and bottom water layers at three stations in the lower Chesapeake Bay between June and September 1993. Using light microscopy a total of 170 phytoplankton taxa were identified. Utilizing epifluorescent microscopy, the picoplankton taxa were distinguished by size, representing species with cells less than 2 microns. Diatoms were the dominant taxa during this period, with lesser representation by the other phytoplankton components. Within the picoplankton category, cyanobacteria were dominant. Statistical analyses of the data indicated the vertical composition and abundance of the phytoplankton was not significantly different over …

Mosquito Population Dynamics During The Establishment Phase Of A Constructed Desert Wetland, April Newman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Nature Preserve at the Clark County Wetlands Park is a constructed wetland that has the potential to produce new mosquito habitat. This thesis evaluates the potential for the development of a mosquito problem at the newly constructed wetland system by assessing the population dynamics of mosquitoes within the Nature Preserve. Based on data collected from May 2001 through January 2002, I describe fluctuations in mosquito genus and relative abundance during the first summer through winter period of wetland development.

Comparisons In Morphology, Reproductive Status, And Feeding Ecology Of Plethodon Cinereus At High And Low Elevations In West Virginia, Mizuki Takahashi

Theses, Dissertations and Capstones

To develop effects of elevation on morphological features, reproductive status, and feeding ecology of Plethodon cinereus in West Virginia, overall comparisons between high (>4000 ft) and low (<1260 ft) elevation populations were made. Adult P. cinereus from high elevations were smaller in SVL (female: p=0.003, male: p<0.001), but stored larger amounts of fat (female: p=0.041, male: p=0.006) in their tails than fromlow elevations. Larger amounts of tail fat could be an adaptation to harsh environments at high elevations. It was determined that in West Virginia, where as females at low elevations oviposit annually, females at high elevations oviposit biennially. Stomach content analysis revealed that salamanders at high elevations were confronted by food shortage. Because of less prey availability and longer winters at high elevations, salamanders at high elevations attained the smaller body size than at low elevations and could not obtain sufficient energy in 1 year to yolk a clutch.