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Farming Systems Research On Crop Diversification, Tillage, And Management Effects On Yield, Pests, And Environmental Quality In A Semi-Arid Environment, Andrew W. Lenssen, U. Sainju, T. Caesar-Tonthat, B. Allen, R. Lartey Jan 2007

Farming Systems Research On Crop Diversification, Tillage, And Management Effects On Yield, Pests, And Environmental Quality In A Semi-Arid Environment, Andrew W. Lenssen, U. Sainju, T. Caesar-Tonthat, B. Allen, R. Lartey

Andrew W. Lenssen

Available water, depleted soil quality, and weed competition are important constraints to crop production in the northern Great Plains. The traditional rotation in the region has been spring wheat with summer fallow, which is used to accrue additional soil moisture for the subsequent wheat crop. Tillage during fallow periods controls weeds, which otherwise would use substantial amounts of water and inorganic nitrogen, decreasing the efficiency of fallow and increasing soil erosion. Chemical fallow and zero tillage systems improve soil water status for subsequent crops (Lenssen et al., 2007a), allowing for increased cropping intensity and improved nutrient cycling (Lenssen et al., …


Microbial Development In Distillers Wet Grains Produced During Fuel Ethanol Production From Corn (Zea Mays), R. Michael Lehman, Kurt A. Rosentrater Jan 2007

Microbial Development In Distillers Wet Grains Produced During Fuel Ethanol Production From Corn (Zea Mays), R. Michael Lehman, Kurt A. Rosentrater

Kurt A. Rosentrater

Distillers grains are coproduced with ethanol and carbon dioxide during the production of fuel ethanol from the dry milling and fermentation of corn grain, yet there is little basic microbiological information on these materials. We undertook a replicated field study of the microbiology of distillers wet grains (DWG) over a 9 day period following their production at an industrial fuel ethanol plant. Freshly produced DWG had a pH of about 4.4, a moisture content of about 53.5% (wet mass basis), and 4 x 10(5) total yeast cells/g dry mass, of which about 0.1% were viable. Total bacterial cells were initially …


The Importance Of Emerging Biobased Industries To Engineering And Technology, Kurt A. Rosentrater, R. Balamuralikrishma Oct 2006

The Importance Of Emerging Biobased Industries To Engineering And Technology, Kurt A. Rosentrater, R. Balamuralikrishma

Kurt A. Rosentrater

Our society has developed an insatiable demand for energy and material goods. Historically, these needs have been met primarily by fossil fuels and other non-renewable raw materials. As environmental concerns grow, however, renewable resources are gaining increased attention. This paper examines the emergence and importance that biobased industries are increasingly beginning to play. A biobased enterprise, similar in concept to a traditional refinery or factory, utilizes conversion technologies to produce various products. These operations are rapidly increasing both in number as well as in capacity throughout this country, and are poised to add significantly to the nation’s energy and material …


Analytical And Experimental Studies Of Properties Of Ethanol Coproduct-Filled Plastics, Robert Tatara, Andrew Otieno, Srikrishna Suraparaju, Kurt A. Rosentrater Oct 2006

Analytical And Experimental Studies Of Properties Of Ethanol Coproduct-Filled Plastics, Robert Tatara, Andrew Otieno, Srikrishna Suraparaju, Kurt A. Rosentrater

Kurt A. Rosentrater

As the renewable fuels industry continues to grow, the quantity of resulting byproducts has expanded in tandem. Currently, these materials are primarily used for animal feed, but at some point will saturate the animal feeds market. Thus, it is necessary to investigate alternative methods and applications by which these coproducts can be utilized. One potential application for these process residues involves plastics manufacturing. Due, in part, to the increasing cost of resins and conventional fillers, alternate fillers have been increasingly sought. Many of these include biological materials such as grasses, bamboo, starch, chicken feathers, soy protein, and cellulose. Not only …


Partitioning Of E. Coli And Enterococci Between Planktonic And Sorbed Phases In Runoff From Pasturelands, Michelle L. Soupir, H. E. Saied Mostaghimi, Elizabeth F. Alphin Jul 2006

Partitioning Of E. Coli And Enterococci Between Planktonic And Sorbed Phases In Runoff From Pasturelands, Michelle L. Soupir, H. E. Saied Mostaghimi, Elizabeth F. Alphin

Michelle L. Soupir

Pathogens are the leading cause of surface water impairments in Virginia. Currently, Nonpoint Source (NPS) pollution models are most frequently used to determine the maximum allowable loading rates of bacteria from identified sources and they typically simulate bacterial transport to surface waters as a planktonic or free pollutant. Very few models attempt to partition between the planktonic and attached phases primarily because data on bacteria partitioning during overland flow events are currently not available. A field study was conducted to evaluate the partitioning of E. coli and enterococci between the planktonic and attached phases in runoff from pasturelands and to …


The Global Relevance Of Bio-Based Industries To Engineering And Technology Education, Kurt A. Rosentrater, Radha Balamuralikrishma Jun 2006

The Global Relevance Of Bio-Based Industries To Engineering And Technology Education, Kurt A. Rosentrater, Radha Balamuralikrishma

Kurt A. Rosentrater

The society in which we live has developed an insatiable demand for energy and material goods. In particular, recent data reveals that the aggressive pursuit of improved standards of living in the highly populated countries of India and China has contributed to increased demand for fossil fuels, which has exacerbated the recent spike in energy costs. Historically, these needs have been met primarily by fossil fuels and other non-renewable raw materials. As environmental concerns grow, however, renewable resources are gaining increased attention. This paper examines the emergence and importance that bio-based industries are increasingly beginning to play. A bio-based enterprise, …


Biorefining Of Renewable Resources—Emerging Opportunities For Engineering Education, Kurt A. Rosentrater Jun 2006

Biorefining Of Renewable Resources—Emerging Opportunities For Engineering Education, Kurt A. Rosentrater

Kurt A. Rosentrater

The society in which we live has developed an insatiable demand for energy and material goods. Historically these needs have primarily been met by utilizing fossil fuels and other nonrenewable raw materials. As environmental concerns grow, however, renewable resources are gaining increased attention. This paper examines industrial biorefineries, which are at the leading edge of the development of emerging biobased industries. Biorefineries, similar in concept to traditional petroleum refineries, utilize various conversion technologies to produce multiple products, including fuels, chemicals, industrial products, and electrical power from renewable biomass sources, such as corn stover, residue straw, perennial grasses, legumes, and other …


Incorporating Targeted Grazing Into Farming Systems, Andrew W. Lenssen, Patrick Hatfield, Hayes Goosey, Sue Blodgett Jan 2006

Incorporating Targeted Grazing Into Farming Systems, Andrew W. Lenssen, Patrick Hatfield, Hayes Goosey, Sue Blodgett

Andrew W. Lenssen

When incorporating targeted grazing into farming systems, livestock producers and farm operators need assurance that the benefits from their activities are worth their investments. This chapter will focus on how integrating grazing, particularly with sheep and goats, into farming systems can offer those benefits. The concepts are not new. Cropping systems were once integrated with livestock production: Livestock gained forage value from crop aftermath, crops were grown to sustain livestock, and livestock were used as implements to produce crops. Today, few cropping systems include livestock. Sheep and goats are traditionally produced on rangelands or pasture forages and supplemented during winter …


Modeling Bacteria Fate And Transport In Watersheds To Support Tmdls, Brian L. Benham, Claire Baffaut, Rebecca W. Zeckoski, Kyle R. Mankin, Yakov A. Pachepsky, Ali M. Sadeghi, Kevin M. Brannan, Michelle L. Soupir, Matthew J. Habersack Jan 2006

Modeling Bacteria Fate And Transport In Watersheds To Support Tmdls, Brian L. Benham, Claire Baffaut, Rebecca W. Zeckoski, Kyle R. Mankin, Yakov A. Pachepsky, Ali M. Sadeghi, Kevin M. Brannan, Michelle L. Soupir, Matthew J. Habersack

Michelle L. Soupir

Fecal contamination of surface waters is a critical water-quality issue, leading to human illnesses and deaths. Total Maximum Daily Loads (TMDLs), which set pollutant limits, are being developed to address fecal bacteria impairments. Watershed models are widely used to support TMDLs, although their use for simulating in-stream fecal bacteria concentrations is somewhat rudimentary. This article provides an overview of fecal microorganism fate and transport within watersheds, describes current watershed models used to simulate microbial transport, and presents case studies demonstrating model use. Bacterial modeling capabilities and limitations for setting TMDL limits are described for two widely used watershed models (HSPF …


Renewable Energy Alternatives—A Growing Opportunity For Engineering And Technology Education, Kurt A. Rosentrater Jan 2006

Renewable Energy Alternatives—A Growing Opportunity For Engineering And Technology Education, Kurt A. Rosentrater

Kurt A. Rosentrater

A hallmark of the United States’ economic growth is an ever-increasing demand for energy, which has traditionally been met primarily by combusting the hydrocarbons found in fossil fuels. As national security and environmental concerns grow, renewable energy resources are gaining increased attention. Unfortunately, there is currently a dearth of renewable energy coverage in engineering and technology curricula. The objectives of this paper are to examine historical energy data for both traditional as well as alternative energy sources, and to motivate educators to address this gap. Even with the progressive developments of non-traditional energy sources over the years, the U.S. still …


Expanding The Role Of Systems Modeling: Considering Byproduct Generation From Biofuel Production, Kurt A. Rosentrater Jan 2006

Expanding The Role Of Systems Modeling: Considering Byproduct Generation From Biofuel Production, Kurt A. Rosentrater

Kurt A. Rosentrater

The bioethanol industry has been experiencing rapid growth over the past several years, and is expected to continue to increase production for the foreseeable future. A vital component to the success of this industry is the sales and marketing of processing residues, which are primarily sold as dried distillers grains with solubles (DDGS). Systems modeling, a technique that has been used to predict future demand for bioethanol, can also be used to determine potential byproduct generation rates. This paper discusses the development of one such model, and presents predicted generation of DDGS as well as carbon dioxide emissions from this …


Update On Ethanol Processing Residue Properties, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan, James Julson, Padmanaban Krishnan Jul 2005

Update On Ethanol Processing Residue Properties, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan, James Julson, Padmanaban Krishnan

Kurt A. Rosentrater

The production of corn-based ethanol in the U.S. is dramatically increasing, and consequently so is the amount of byproduct materials generated from this processing sector. These coproduct streams are currently solely utilized as livestock feed, which is a route that provides ethanol processors with a substantial revenue source and significantly increases the profitability of the production process. With the construction and operation of many new plants in recent years, these residuals do, however, have much potential for value-added processing and utilization in other sectors as well. This option holds promise of economic benefit for corn processors, especially if the livestock …


Renewable Energy Alternatives: Current Status And Capacities, Kurt A. Rosentrater, Youakim Al-Kalaani Apr 2005

Renewable Energy Alternatives: Current Status And Capacities, Kurt A. Rosentrater, Youakim Al-Kalaani

Kurt A. Rosentrater

A key to the United States’ economic growth is an ever-increasing demand for energy, which has traditionally been met primarily by combusting the hydrocarbons found in fossil fuels. As environmental concerns grow, renewable energy resources are gaining increasing attention. To aid both researchers as well as educators, this paper examines historical energy data for both traditional as well as alternative energy sources. Even with the progressive developments of non-traditional energy sources over the years, the U.S. still receives more than 90% of its energy from fossil and nuclear fuels. Explicit examination of the alternative energy sector has revealed that hydroelectric …


Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff Jan 2005

Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff

Lisa A. Schulte Moore

Within the northern Great Lakes region, mesoscale (10s to 100s of km2) forest patterning is driven by disturbance dynamics. Using original Public Land Survey (PLS) records in northern Wisconsin, USA, we study spatial patterns of wind and fire disturbances during the pre-Euroamerican settlement period (ca. 1850). Our goals were: (1) to determine how effectively wind and fire disturbance can be econstructed from the PLS, (2) to assess the roles of wind and fire in shaping vegetation patterns, (3) to evaluate landscape to regional controls of wind and fire regimes, and (4) to assess the potential for interactions between these disturbances. …


The Ivory-Billed Woodpecker In Mississippi?, Stephen J. Dinsmore Jan 2005

The Ivory-Billed Woodpecker In Mississippi?, Stephen J. Dinsmore

Stephen J Dinsmore

In April the environmental community received a real surprise--the Ivory-billed Woodpecker, long thought to be extinct, had apparently been rediscovered in Arkansas! As the news unfolded, the world learned that a team of researchers had been tracking at least one woodpecker, a lone male, for more than a year in the Cache River region of east-central Arkansas. The rediscovery of a bird presumed extinct for more than 60 years subsequently galvanized the environmental community and garnered much-needed support for the preservation of the Southeast's remaining old growth bottomland forests and endangered species recovery.


Waterfowl Abundance And Distribution In The Mississippi Delta, Stephen J. Dinsmore, Aaron T. Pearse, Richard M. Kaminski, Kenneth J. Reinecke Jan 2005

Waterfowl Abundance And Distribution In The Mississippi Delta, Stephen J. Dinsmore, Aaron T. Pearse, Richard M. Kaminski, Kenneth J. Reinecke

Stephen J Dinsmore

During mornings of empty skies, a duck hunter has plenty of time to ponder the question, "Where are all the ducks?" Invariable, the distraught hunter arrives at an unhappy conclusion: the ducks are not going to show up, so they must be elsewhere. The typical progression of an unsuccessful morning of hunting leads to multiple explanations as to why there weren't any ducks, such as mild winter temperatures in and north of Mississippi, not enough rain to attract ducks, too much rain and the ducks are scattered, the region doesn't have enough food to attract and hold ducks, the ducks …


Hamiota, A New Genus Of Freshwater Mussel (Bivalvia: Unionidae) From The Gulf Of Mexico Drainages Of The Southeastern United States, Kevin J. Roe, Paul D. Hartfield Jan 2005

Hamiota, A New Genus Of Freshwater Mussel (Bivalvia: Unionidae) From The Gulf Of Mexico Drainages Of The Southeastern United States, Kevin J. Roe, Paul D. Hartfield

Kevin J. Roe

Hamiota, a new genus of freshwater mussel containing four species formerly assigned to the genus Lampsilis Rafinesque, 1820, is described. In addition to the genus Lampsilis, members of Hamiota had previously been placed in the genera Villosa Frierson, 1927, and Ligumia Swainson, 1840. Several characters including the packaging of their larvae in a superconglutinate lure to attract host fishes, placement and shape of the marsupia, and release of glochidia through the excurrent siphon, support the recognition of these species as a distinct genus.


Pre-Euroamerican Distribution Of Pine Warblers (Dendroica Pinus) In Wisconsin: A Tool For Setting Regional Conservation Priorities, Lisa A. Schulte, Anna M. Pidgeon, David J. Mladenoff Jan 2005

Pre-Euroamerican Distribution Of Pine Warblers (Dendroica Pinus) In Wisconsin: A Tool For Setting Regional Conservation Priorities, Lisa A. Schulte, Anna M. Pidgeon, David J. Mladenoff

Lisa A. Schulte Moore

A common goal of conservation and management plans is to maintain populations of species of conservation concern at some historic level that was a product of environmental conditions at a time when they were less influenced by humans than at present. Conservation planning also includes consideration of the distribution, abundance, and reproductive success of a species, all of which are affected by both the amount and spatial pattern of habitat. In this work, we have fused the fields of spatial and historical ecology to provide a perspective that includes an estimate of a bird species’ distribution just prior to Euroamerican …


Meeting The Scientific Needs Of Ecological Risk Assessment In A Regulatory Context, Steven P. Bradbury, Tom C. Feitel, Cornelis J. Van Leeuwen Dec 2004

Meeting The Scientific Needs Of Ecological Risk Assessment In A Regulatory Context, Steven P. Bradbury, Tom C. Feitel, Cornelis J. Van Leeuwen

Steven P. Bradbury

During the past decade, the field of ecological risk assessment has progressed considerably. Advances have come from such international bodies as the Organisation for Economic Co-operation and Development (OECD), the World Health Organisation (WHO), the European and Mediterranean Plant Protection Organisation (EPPO), and the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) (1–8). Risk assessments have played a critical role in the development of various regulations within the European Commission (EC) as well as in other parts of the world, including the United States, Canada, and Japan (9–17). But scientists and regulators are faced with three significant challenges: streamlining …


Release And Transport Of Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir, Saied Mostaghimi, Eugene R. Yagow, David H. Vaughan Aug 2004

Release And Transport Of Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir, Saied Mostaghimi, Eugene R. Yagow, David H. Vaughan

Michelle L. Soupir

Land applications of manure from confined animal systems and direct deposit by grazing animals are both major sources of nutrients in streams. An understanding of the overland transport mechanisms from land applied waste is needed to improve design of best management practices and modeling of NPS pollution. Release and transport plots were established to study in-field nutrient release and transport from pasturelands receiving phosphorus based livestock waste applications. The release plots determined the concentrations available to be transported to the edge of the field in runoff. Four manure treatments (turkey litter, liquid dairy manure, standard cowpies, and none) and three …


A Correlation Study Of Wind Speeds At Norski Runs And Valders Hall Of Science, Paul D. B. Skrade, Dale M. Nimrod Mar 2004

A Correlation Study Of Wind Speeds At Norski Runs And Valders Hall Of Science, Paul D. B. Skrade, Dale M. Nimrod

Paul D. B. Skrade

1976 and 1977 wind speeds were recorded from the roof of Valders Hall of Science, Luther College, Decorah, Iowa in a correlation study of wind-sun energy. Summer 2004 wind speeds and directions were recorded with the hopes of correlating the speeds at Valders Hall of Science and at Norski Runs, Chattahoochie County Park, Decorah, Iowa, a site for a potential Luther College wind farm. Motivation behind the study was to determine if topology of Upper Iowa River Valley affected wind speeds.


Linear And Nonlinear Effects Of Habitat Structure On Composition And Abundance In The Macroinvertebrate Community Of A Large River, Timothy W. Stewart, Tammy L. Shumaker, Thomas A. Radzio Jan 2003

Linear And Nonlinear Effects Of Habitat Structure On Composition And Abundance In The Macroinvertebrate Community Of A Large River, Timothy W. Stewart, Tammy L. Shumaker, Thomas A. Radzio

Timothy W. Stewart

We used an experiment and regression analyses to quantify effects of spatial variation in habitat structure abundance on a riverine macroinvertebrate community under winter conditions. Concrete slabs (0.21 m2; n 5 24) with different numbers of stones (mean individual stone surface area 5 6.44 cm2) attached to upper faces were placed in the James River and retrieved after 28 d. Macroinvertebrate abundance and taxonomic richness on slabs were significantly positively related to stone abundance. Total macroinvertebrate abundance and abundance of oligochaetes (Nais spp.), Asiatic clams (Corbicula fluminea), caddisflies (Leptoceridae), riffle beetles (Elmidae) and stoneflies (Strophopteryx sp.) were linearly related to …


Seventy Years Of Forest Change In The Northern Great Lakes Region, Usa, Lisa A. Schulte-Moore, Thomas R. Crow, Dave Cleland Jan 2003

Seventy Years Of Forest Change In The Northern Great Lakes Region, Usa, Lisa A. Schulte-Moore, Thomas R. Crow, Dave Cleland

Lisa A. Schulte Moore

The rates and magnitudes of forest change have important social and economic implications. We address facets of change associated with 20th century recovery of the U.S. Lake States (Michigan, Wisconsin, and Minnesota) forests from the Great Cutover, and discuss ecological and socioeconomic implications for future forest resources.


Overview Of Data And Conceptual Approaches For Derivation Of Quantitative Structure-Activity Relationships For Ecotoxicological Effects Of Organic Chemicals, Steven P. Bradbury, Christine L. Russom, Gerald T. Ankley, T. Wayne Schultz, John D. Walker Jan 2003

Overview Of Data And Conceptual Approaches For Derivation Of Quantitative Structure-Activity Relationships For Ecotoxicological Effects Of Organic Chemicals, Steven P. Bradbury, Christine L. Russom, Gerald T. Ankley, T. Wayne Schultz, John D. Walker

Steven P. Bradbury

The use of quantitative structure–activity relationships (QSARs) in assessing potential toxic effects of organic chemicals on aquatic organisms continues to evolve as computational efficiency and toxicological understanding advance. With the everincreasing production of new chemicals, and the need to optimize resources to assess thousands of existing chemicals in commerce, regulatory agencies have turned to QSARs as essential tools to help prioritize tiered risk assessments when empirical data are not available to evaluate toxicological effects. Progress in designing scientifically credible QSARs is intimately associated with the development of empirically derived databases of well-defined and quantified toxicity endpoints, which are based on …


Qsar Prioritization Of Chemical Inventories For Endocrine Disruptor Testing, Steven P. Bradbury, Patricia Schmeider, Ovanes Mekenyan, Gilman Veith Jan 2003

Qsar Prioritization Of Chemical Inventories For Endocrine Disruptor Testing, Steven P. Bradbury, Patricia Schmeider, Ovanes Mekenyan, Gilman Veith

Steven P. Bradbury

Binding affinity between chemicals and the estrogen receptor (ER) serves as an indicator of the potential to cause endocrine disruption through this receptor-mediated endocrine pathway. Estimating ER-binding affinity is, therefore, one strategic approach to reducing the costs of screening chemicals for potential risks of endocrine disruption. While measuring ER binding with in vitro assays may be the first choice in prioritizing chemicals for additional in vitro or in vivo estrogenicity testing, the time and costs associated with screening thousands of chemicals is prohibitive. Recent advances in 3D modeling of the reactivity of flexible structures make in silico methods for estimating …


An Overview Of The Use Of Quantitative Structure-Activity Relationships For Ranking And Prioritzing Large Chemical Inventories For Environmental Risk Assessments, Steven P. Bradbury, Christine L. Russom, Roger L. Breton, John D. Walker Jan 2003

An Overview Of The Use Of Quantitative Structure-Activity Relationships For Ranking And Prioritzing Large Chemical Inventories For Environmental Risk Assessments, Steven P. Bradbury, Christine L. Russom, Roger L. Breton, John D. Walker

Steven P. Bradbury

Ecological risk assessments for chemical stressors are used to establish linkages between likely exposure concentrations and adverse effects to ecological receptors. At times, it is useful to conduct screening risk assessments to assist in prioritizing or ranking chemicals on the basis of potential hazard and exposure assessment parameters. Ranking of large chemical inventories can provide evidence for focusing research and/or cleanup efforts on specific chemicals of concern. Because of financial and time constraints, data gaps exist, and the risk assessor is left with decisions on which models to use to estimate the parameter of concern. In this review, several methods …


Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: Ii. An Evaluation Of Potential Interactive Mechanisms, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer Jan 2003

Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: Ii. An Evaluation Of Potential Interactive Mechanisms, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer

Steven P. Bradbury

It has been demonstrated that simultaneous exposure of Daphnia magna to suspended solids and a carbamate pesticide potentiates the toxic response to the pesticide. The toxicodynamics between these stressors were investigated to determine possible mechanisms of interaction. Three experimental series were conducted with D. magna to determine: the effect of food availability on carbofuran toxicity; the effect of food availability on jointly administered carbofuran and suspended solids; and changes in the magnitude of effects which can occur with suspended solids of different composition. These experiments demonstrated that both carbofuran toxicity and the joint toxicity of carbofuran and suspended solids to …


Quantitative Structure-Activity Relationship Models For Prediction Of Estrogen Receptor Binding Affinity Of Structurally Diverse Chemicals, Steven P. Bradbury, Patricia K. Schmeider, Gerald Ankley, Ovanes Mekenyan, John D. Walker Jan 2003

Quantitative Structure-Activity Relationship Models For Prediction Of Estrogen Receptor Binding Affinity Of Structurally Diverse Chemicals, Steven P. Bradbury, Patricia K. Schmeider, Gerald Ankley, Ovanes Mekenyan, John D. Walker

Steven P. Bradbury

The demonstrated ability of a variety of structurally diverse chemicals to bind to the estrogen receptor has raised the concern that chemicals in the environment may be causing adverse effects through interference with nuclear receptor pathways. Many structure–activity relationship models have been developed to predict chemical binding to the estrogen receptor as an indication of potential estrogenicity. Models based on either two-dimensional or three-dimensional molecular descriptions that have been used to predict potential for binding to the estrogen receptor are the subject of the current review. The utility of such approaches to predict binding potential of diverse chemical structures in …


Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: I. Interactive Effects, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer Jan 2003

Influence Of Suspended Solids On Acute Toxicity Of Carbofuran To Daphnia Magna: I. Interactive Effects, Steven P. Bradbury, Carl Herbrandson, Deborah L. Swackhamer

Steven P. Bradbury

This study explored the effects on Daphnia magna from exposure to the pesticide carbofuran in combination with stress from suspended solids exposure. Our objective was to assess whether suspended solids affects the toxicodynamic response of D. magna to carbofuran. A series of laboratory experiments was performed where animals were exposed to carbofuran concentrations ranging from 0 to 160 mg/l in combination with suspended solids concentrations ranging from 0 to 10,000 mg/l. In the absence of suspended solids, effects of carbofuran were dose dependent and resulted in an EC(sub)50 of 92 mg/l. Exposure to suspended solids, up to extreme levels that …


Modeling Vegetative Filter Performance With Vfsmod, Matthew J. Helmers, Dean E. Eisenhauer, Michael G. Dosskey, Thomas G. Franti Apr 2002

Modeling Vegetative Filter Performance With Vfsmod, Matthew J. Helmers, Dean E. Eisenhauer, Michael G. Dosskey, Thomas G. Franti

Matthew J. Helmers

The model VFSMOD was used to investigate the effect of varying watershed characteristics and buffer dimensions on the sediment trapping efficiency of vegetative filters. This investigation allows for a better understanding of how watershed characteristics, buffer dimensions, and storm characteristics impact the performance of vegetative filters. Using VFSMOD, relationships that estimate sediment trapping efficiency from the ratio of filter area and field area were developed for different sites. These relationships have been applied for field assessment of concentrated flow.