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Full-Text Articles in Life Sciences

Butterflies In The Highly Fragmented Prairies Of Central Iowa: How The Landscape Affects Population Isolation, Leslie Ries Jan 1998

Butterflies In The Highly Fragmented Prairies Of Central Iowa: How The Landscape Affects Population Isolation, Leslie Ries

Retrospective Theses and Dissertations

Ever since MacArthur and Wilson presented the Theory of Island Biogeography in 1963, there has been considerable concern about the ability of a system of isolated reserves to retain species diversity or viable populations over extended periods of time. Despite this interest, very little is known about how readily individuals move around in their landscape. Edges and corridors have both been targeted as landscape features that may have important consequences for directing movement and thereby affecting isolation. Edges may form a barrier to movement reducing the probability that an individual will leave a patch. For individuals that have left, they ...


On-Line Coupling Of Capillary Electrophoresis And Liquid Chromatography With Electrospray Ionization Mass Spectrometry For Protein Characterization , Liyu Yang Jan 1998

On-Line Coupling Of Capillary Electrophoresis And Liquid Chromatography With Electrospray Ionization Mass Spectrometry For Protein Characterization , Liyu Yang

Retrospective Theses and Dissertations

On-line coupling of capillary isoelectric focusing (CIEF) and liquid chromatography (LC) with electrospray ionization mass spectrometry (ESIMS) is utilized for protein characterization;A microdialysis junction, based on a microdialysis membrane connecting both a separation capillary and a short, sharply tapered microelectrospray emitter capillary, is demonstrated for CIEF-ESIMS. Besides the electrical connection across the microdialysis junction, post-run acidification via the dialysis membrane is demonstrated for enhancing the protonation and the ionization efficiency of focused proteins while maintaining separation efficiency, resolution, and sensitivity in CIEF-ESIMS;On-line combination of CIEF with ESI-FTICRMS is demonstrated for high resolution analysis of model proteins, human hemoglobin ...


Capillary Electrophoresis Separation Of Neutral Organic Compounds, Pharmaceutical Drugs, Proteins And Peptides, Enantiomers And Anions , Wei-Liang Ding Jan 1998

Capillary Electrophoresis Separation Of Neutral Organic Compounds, Pharmaceutical Drugs, Proteins And Peptides, Enantiomers And Anions , Wei-Liang Ding

Retrospective Theses and Dissertations

Addition of a novel anionic surfactant, namely lauryl polyoxyethylene sulfate, to an aqueous-acetonitrile electrolyte makes it possible to separate nonionic organic compounds by capillary electrophoresis. Separation is based on differences in the association between analytes and the surfactant. Highly hydrophobic compounds such as polyaromatic hydrocarbons are well separated by this new surfactant. Migration times of analytes can be readily changed over an unusually large range by varying the additive concentration and the proportion of acetonitrile in the electrolyte. Several examples are given, including the separation of four methylbenz (a) anthracene isomers and the separation of normal and deuterated acetophenone;The ...


Development Of A New High-Rate Anaerobic Process For The Treatment Of Industrial And Domestic Wastewaters: The Anaerobic Migrating Blanket Reactor (Ambr) , Largus Theodora Angenent Jan 1998

Development Of A New High-Rate Anaerobic Process For The Treatment Of Industrial And Domestic Wastewaters: The Anaerobic Migrating Blanket Reactor (Ambr) , Largus Theodora Angenent

Retrospective Theses and Dissertations

The anaerobic migrating blanket reactor (AMBR) was developed as a new high-rate system for the treatment of industrial and domestic wastewaters, at Iowa State University. The AMBR, a continuously fed, compartmentalized reactor, required mechanical mixing to obtain a sufficient biomass/substrate contact. The formation of granular biomass was not dependent on a hydraulic upflow pattern in the reactor, but was dependent on biomass migration over the horizontal plane of the reactor and the settling characteristics of the final compartment. To prevent acclimation of biomass in the final compartment, the flow was reversed in a horizontal matter. Keeping the pH sufficiently ...


Gene Flow At A Snail's Pace: Phylogeography And Conservation Genetics Of Relict Populations Of The Iowa Pleistocene Snail , Tamara Kay Ross Jan 1998

Gene Flow At A Snail's Pace: Phylogeography And Conservation Genetics Of Relict Populations Of The Iowa Pleistocene Snail , Tamara Kay Ross

Retrospective Theses and Dissertations

The Iowa Pleistocene snail, Discus macclintocki, is a federally endangered land snail found only in northeast Iowa and northwestern Illinois. This species is believed to be a glacial relict with populations isolated for the last 16,000 years. In this study, I investigated the amount of genetic variation within, and the gene flow among, ten isolated populations of the Iowa Pleistocene snail, Discus macclintocki (Baker). I sequenced part of the 16s region of the mitochondrial DNA from 175 snails. Populations clustered clearly by watershed, suggesting that flooding events may have been the historical avenue of gene flow rather than overland ...


The Poplar-Leaf Rust Pathosystem: Inheritance Of Resistance And Pathogenic Variability , Girma Melesse Tabor Jan 1998

The Poplar-Leaf Rust Pathosystem: Inheritance Of Resistance And Pathogenic Variability , Girma Melesse Tabor

Retrospective Theses and Dissertations

Among diseases that cause serious yield reduction on Populus deltoides is leaf rust caused by Melampsora medusae. The objectives of this project were to study the pathogenic variability of M. medusae, the genetic basis of inheritance of M. medusae resistance in a family of P. deltoides; and to identify molecular markers linked to a leaf-rust resistant locus. Three pathotypes of M. medusae were identified on the basis of their differential reaction to three Populus clones. Pathotypes D-93, F-93, and IL-48 were compatible with clone 1-488 (P. X euramericana). F-93 and IL48 were also compatible with clone 57-276 (P. deltoides X ...


Assessment And Simulation Of Atrazine As Influenced By Drainage And Irrigation: An Interface Between Rzwqm And Arcview Gis , Ana Sofia De Oliveira Nobre Azevedo Jan 1998

Assessment And Simulation Of Atrazine As Influenced By Drainage And Irrigation: An Interface Between Rzwqm And Arcview Gis , Ana Sofia De Oliveira Nobre Azevedo

Retrospective Theses and Dissertations

Atrazine is the most frequently detected herbicide in groundwater. For these reasons, atrazine's dynamics need to be studied, and work is needed to develop and calibrate mathematical models to help in determining best management practices to minimize contamination. This study was designed to make a small contribution in solving some of the environmental related problems;In the first part of this study, macroporosity of an agricultural soil in Iowa was characterized. This study confirmed that under saturated and partially saturated flow conditions, macropore flow was a dominant mechanism for water and chemical transport;Atrazine's movement through the soil ...


Valuing Environmental Amenities With Nonparametric And Semiparametric Methods , John Russell Crooker Jan 1998

Valuing Environmental Amenities With Nonparametric And Semiparametric Methods , John Russell Crooker

Retrospective Theses and Dissertations

The dissertation consists of three essays. Each essay is presented in its own chapter beginning with chapter II. While each chapter is written as a stand alone document, the essays complement each other in subject matter, methodology and relevance to the econometrics and natural resource economics literature. In particular, the most fundamental problem investigated is how can we, as precisely as possible, value non-market goods without making parametric assumptions that may influence welfare estimates;The three essays comprising this dissertation contribute to the knowledge of the economics valuation literature in several important ways. First, semi-nonparametric and nonparametric estimators are rigorously ...


Localized Soil Compaction And Soil Doming Of The Fertilizer Injection Zone To Control Nitrate Leaching , Daniel Eric Ressler Jan 1998

Localized Soil Compaction And Soil Doming Of The Fertilizer Injection Zone To Control Nitrate Leaching , Daniel Eric Ressler

Retrospective Theses and Dissertations

Chemical movement is fundamental to production agriculture. Crop roots and nutrients must be in contact for optimum crop growth. In the pursuit of this goal, nitrogen that is applied in fertilizers is often leached prior to crop uptake. Means to limit fertilizer leaching to conserve resources are needed;Application method plays a role in the way chemicals move through soil. Structured soil column effluent studies suggest that leaching could be reduced if chemicals are allowed to penetrate soil aggregates prior to saturation by an infiltrating solution. In well structured soil, mixing chemicals with a limited volume of soil and destroying ...


Rationalizing Nature: Attitudes Toward Land Tenure Change And The Environment In Three Communities In Central Quintana Roo, Mexico , Susan Kathryn Jarnagin Jan 1998

Rationalizing Nature: Attitudes Toward Land Tenure Change And The Environment In Three Communities In Central Quintana Roo, Mexico , Susan Kathryn Jarnagin

Retrospective Theses and Dissertations

Three studies were done to assess the attitudes of farmers in central Quintana Roo about changes in the land tenure system and toward their tropical forest environment. Three ejidos were selected, to represent the range of types of communities in the area;Recent visions of "modernization" in Mexico have involved a large amount of privatization, including encouraging privatization of ejido (community-owned) land. The attitudes of residents of three communities towards land privatization and tree planting and care were analyzed. The residents of the two more traditional Maya communities had strong feelings about the importance of maintaining the ejido system of ...