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Articles 1921 - 1950 of 2277

Full-Text Articles in Civil and Environmental Engineering

Biocompatibility Of Te–As–Se Glass Fibers For Cell-Based Bio-Optic Infrared Sensors, Allison A. Wilhelm, Pierre Lucas, Diana L. Derosa, Mark R. Riley Jan 2007

Biocompatibility Of Te–As–Se Glass Fibers For Cell-Based Bio-Optic Infrared Sensors, Allison A. Wilhelm, Pierre Lucas, Diana L. Derosa, Mark R. Riley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The chemical stability and toxicity of Te–As–Se (TAS) infrared fibers are investigated. These fibers are used for biosensing applications that involve direct contact with live cultivated human cells. It is shown that TAS fibers exhibit a small oxidation layer after extended exposure to air. This layer is highly soluble in water and easily removed. However, the TAS glass itself is stable in water over several days. While oxidized fibers release arsenate ions, which result in toxic effects to the cells, fresh or washed fibers show no toxic effects. A good correlation is shown between surface etching and the disappearance of …


Subsurface Characterization Using Textural Features Extracted From Gpr Data, R. S. Freeland, Lameck O. Odhiambo Jan 2007

Subsurface Characterization Using Textural Features Extracted From Gpr Data, R. S. Freeland, Lameck O. Odhiambo

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Subsurface conditions can be non-intrusively mapped by observing and grouping patterns of similarity within ground-penetrating radar (GPR) profiles. We have observed that the intricate and often visually indiscernible textural variability found within a complex GPR image possesses important parameters that help delineate regions of similar subsurface characteristics. In this study, we therefore examined the feasibility of using textural features extracted from GPR data to automate subsurface characterization. The textural features were matched to a “fingerprint” database of previous subsurface classifications of GPR textural features and the corresponding physical probings of subsurface conditions. Four textural features (energy, contrast, entropy, and homogeneity) …


Analysis Of An Ion‐Selective Electrode Based Methodology For Integrated On‐The‐Go Mapping Of Soil Ph, Potassium, And Nitrate Contents, B. Sethuramasamyraja, V. I. Adamchuk, D. B. Marx, A. Dobermann, G. E. Meyer, D. D. Jones Jan 2007

Analysis Of An Ion‐Selective Electrode Based Methodology For Integrated On‐The‐Go Mapping Of Soil Ph, Potassium, And Nitrate Contents, B. Sethuramasamyraja, V. I. Adamchuk, D. B. Marx, A. Dobermann, G. E. Meyer, D. D. Jones

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Knowledge of the spatial variation of soil attributes is critical for precision agriculture. On‐the‐go soil sensors have been able to provide relatively high mapping density while assessing this variation. A new ion‐selective electrode (ISE) based approach was developed and tested for simultaneous mapping of soil pH, residual nitrate (NO3 -), and soluble potassium (K+) contents. In this article, results of laboratory experiments investigating the effects of key measurement factors on ISE performance are presented. In addition to four different soils, these factors included: soil/water ratio (SWR), quality of water used for electrode rinsing (QWR) and for …


Spatiotemporal Variations In Growing Season Exchanges Of Co2, H2o, And Sensible Heat In Agricultural Fields Of The Southern Great Plains, Marc L. Fischer, Dave P. Billesbach, Joseph A. Berry, William J. Riley, Margaret S. Torn Jan 2007

Spatiotemporal Variations In Growing Season Exchanges Of Co2, H2o, And Sensible Heat In Agricultural Fields Of The Southern Great Plains, Marc L. Fischer, Dave P. Billesbach, Joseph A. Berry, William J. Riley, Margaret S. Torn

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Climate, vegetation cover, and management create finescale heterogeneity in unirrigated agricultural regions, with important but not well quantified consequences for spatial and temporal variations in surface CO2, water, and heat fluxes. Eddy covariance fluxes were measured in seven agricultural fields—comprising winter wheat, pasture, and sorghum—in the U.S. Southern Great Plains (SGP) during the 2001–03 growing seasons. Land cover was the dominant source of variation in surface fluxes, with 50%–100% differences between fields planted in winter–spring versus fields planted in summer. Interannual variation was driven mainly by precipitation, which varied more than twofold between years. Peak aboveground biomass and growing season …


Recasting Dilemma Zone Design As A Marginal Cost-Benefit Problem, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta Jan 2007

Recasting Dilemma Zone Design As A Marginal Cost-Benefit Problem, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta

Department of Civil and Environmental Engineering: Faculty Publications

One control objective at high-speed isolated intersections is to provide safe phase transition by minimizing the occurrence of high-speed vehicles in the dilemma zone before the phase is terminated. An upper limit for extending the green (maximum green time) is used to avoid an indefinite extension of the main-street green. Currently, the maximum green times are chosen by using engineering judgment. This approach does not explicitly consider the trade-offs between safety and delay and hence often results in both unsafe and inefficient performance at the intersection under medium to heavy traffic volumes. The dilemma problem is recast as one of …


Limitations Of Simultaneous Gap-Out Logic, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta Jan 2007

Limitations Of Simultaneous Gap-Out Logic, Anuj Sharma, Darcy M. Bullock, Srinivas Peeta

Department of Civil and Environmental Engineering: Faculty Publications

The current practice of specifying simultaneous gap-out logic places constraints on signal controller logic. These constraints cannot be achieved under high traffic flow conditions, and degraded signal efficiency and dilemma zone protection often result. This study documents the phenomenon described above with set-back detectors at an instrumented intersection in Noblesville, Indiana, and characterizes the problem of dilemma zone protection as being traffic-volume dependent, a factor that should be carefully considered before the simultaneous gap-out logic is applied. Implementation of simultaneous gap-out logic led to max out ranging from 3.5% to 40% of cycles per hour during peak traffic flow periods …


Event-Based Data Collection For Generating Actuated Controller Performance Measures, Edward J. Smaglik, Anuj Sharma, Darcy M. Bullock, James R. Sturdevant, Gary Duncan Jan 2007

Event-Based Data Collection For Generating Actuated Controller Performance Measures, Edward J. Smaglik, Anuj Sharma, Darcy M. Bullock, James R. Sturdevant, Gary Duncan

Department of Civil and Environmental Engineering: Faculty Publications

Cycle-by-cycle data have been shown to be effective in the analysis of a signalized intersection with measures of effectiveness such as volume-to-capacity ratios, arrival type, and average vehicular delay. Currently, actuated traffic controllers are unable to store vehicle counts and vehicle occupancy in cycle-by-cycle bins, requiring extra equipment and personnel to collect data in these bins. The objective of this research was to develop an integrated general purpose data collection module that time stamps detector and phase state changes within a National Electrical Manufacturers Association actuated traffic signal controller and uses those data to provide quantitative graphs to assess arterial …


Material Selection And Design Consideration For Moisture Damage Of Asphalt Pavement, Jamilla Emi Sudo Lutif, Yong-Rak Kim Dec 2006

Material Selection And Design Consideration For Moisture Damage Of Asphalt Pavement, Jamilla Emi Sudo Lutif, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

No abstract provided.


Crumb Rubber In Performance-Graded Asphalt Binder, Wayne Jensen, Magdy Abdelrahman Nov 2006

Crumb Rubber In Performance-Graded Asphalt Binder, Wayne Jensen, Magdy Abdelrahman

Nebraska Department of Transportation: Research Reports

No abstract provided.


Self-Similarity Of Mean Flow In Pipe Turbulence, Junke Guo Jun 2006

Self-Similarity Of Mean Flow In Pipe Turbulence, Junke Guo

Department of Civil and Environmental Engineering: Faculty Publications

Based on our previous modified log-wake law in turbulent pipe ‡flows, we invent two compound similarity numbers (Y;U), where Y is a combination of the inner variable y+ and outer variable , and U is the pure exect of the wall. The two similarity numbers can well collapse mean velocity profile data with different moderate and large Reynolds numbers into a single universal profile. We then propose an arctangent law for the buffer layer and a general log law for the outer region in terms of (Y;U). From Milikan’s maximum velocity law and the Princeton superpipe data, we derive the …


Competitive Metagenomic Dna Hybridization Identifies Host-Specific Microbial Genetic Markers In Cow Fecal Samples, Orin C. Shanks, Jorge W. Santo Domingo, Regina Lamendella, Catherine A. Kelty, James E. Graham Jun 2006

Competitive Metagenomic Dna Hybridization Identifies Host-Specific Microbial Genetic Markers In Cow Fecal Samples, Orin C. Shanks, Jorge W. Santo Domingo, Regina Lamendella, Catherine A. Kelty, James E. Graham

United States Environmental Protection Agency: Publications

Several PCR methods have recently been developed to identify fecal contamination in surface waters. In all cases, researchers have relied on one gene or one microorganism for selection of host-specific markers. Here we describe the application of a genome fragment enrichment (GFE) method to identify host-specific genetic markers from fecal microbial community DNA. As a proof of concept, bovine fecal DNA was challenged against a porcine fecal DNA background to select for bovine-specific DNA sequences. Bioinformatic analyses of 380 bovine enriched metagenomic sequences indicated a preponderance of Bacteroidales-like regions predicted to encode membrane-associated and secreted proteins. Oligonucleotide primers capable …


Behavior And Design Of Buried Concrete Pipes, Ece Erdogmus, Maher K. Tadros Jun 2006

Behavior And Design Of Buried Concrete Pipes, Ece Erdogmus, Maher K. Tadros

Nebraska Department of Transportation: Research Reports

No abstract provided.


On The Spatial Nature Of The Groundwater Pumping Externality, Nicholas Brozovic, David L. Sunding, David Zilberman May 2006

On The Spatial Nature Of The Groundwater Pumping Externality, Nicholas Brozovic, David L. Sunding, David Zilberman

Daugherty Water for Food Global Institute: Faculty Publications

Most existing economic analyses of optimal groundwater management use single-cell aquifer models, which assume that an aquifer responds uniformly and instantly to ground- water pumping. This paper demonstrates how spatially explicit aquifer response equations from the water resources engineering literature may be embedded in a general economic framework. Calibration of our theoretical model to published economic studies of spe- cific aquifers demonstrates that, by averaging basin drawdown across the entire resource, existing studies generally understate the magnitude of the groundwater pumping external- ity relative to spatially explicit models. For the aquifers studied, the drawdown predicted by single- cell models may …


Multiobjective Plan Selection Optimization For Traffic Responsive Control, Montasir M. Abbas, Anuj Sharma May 2006

Multiobjective Plan Selection Optimization For Traffic Responsive Control, Montasir M. Abbas, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

Optimal coordination of traffic signals requires proper activation of timing plans to match current traffic conditions. One of the greatest challenges in configuring a traffic responsive plan selection control mode is how to select only n number of timing plans (restricted by traffic controller memory limitations) to address possibly all traffic conditions/states that can be encountered in the field, for a specific site, but most importantly, how to associate each of these traffic conditions to one of the n timing plans stored in the traffic controller. This paper uses a multiobjective non-dominated sorting genetic algorithm to (1) select the best …


Course Portfolio For Arch333/Cnst305: Building Environmental Technical Systems, Tim Wentz Apr 2006

Course Portfolio For Arch333/Cnst305: Building Environmental Technical Systems, Tim Wentz

UNL Faculty Course Portfolios

Due to the critical nature of team-based learning in this course, I propose to study the learning aspects of team-based learning, as I envision it in this course. Not having formally investigated this issue previously, I am left with a sense that some teams perform much better than other teams. I am looking for those criteria that separate the good teams from underperforming teams. Some of the issues that occur to me as I start this process include the following: - Team size - Academic diversity - Discipline diversity - Gender diversity - Geographic diversity How students best learn in …


Risk Of Colon Cancer In Hereditary Non-Polyposis Colorectal Cancer Patients As Predicted By Fuzzy Modeling: Influence Of Smoking, Rhonda M. Brand, David D. Jones, Henry T. Lynch, Randall E. Brand, Patrice Watson, Ramesh Ashwathnayaran, Hemant K. Roy Mar 2006

Risk Of Colon Cancer In Hereditary Non-Polyposis Colorectal Cancer Patients As Predicted By Fuzzy Modeling: Influence Of Smoking, Rhonda M. Brand, David D. Jones, Henry T. Lynch, Randall E. Brand, Patrice Watson, Ramesh Ashwathnayaran, Hemant K. Roy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

AIM: To investigate whether a fuzzy logic model could predict colorectal cancer (CRC) risk engendered by smoking in hereditary non-polyposis colorectal cancer (HNPCC) patients.

METHODS: Three hundred and forty HNPCC mismatch repair (MMR) mutation carriers from the Creighton University Hereditary Cancer Institute Registry were selected for modeling. Age-dependent curves were generated to elucidate the joint effects between gene mutation (hMLH1 or hMSH2), gender, and smoking status on the probability of developing CRC.

RESULTS: Smoking significantly increased CRC risk in male hMSH2 mutation carriers (P < 0.05). hMLH1 mutations augmented CRC risk relative to hMSH2 mutation carriers for males (P < 0.05). Males had a significantly higher risk of CRC than females for hMLH1 non smokers (P < 0.05), hMLH1 smokers (P < 0.1) and hMSH2 smokers (P < 0.1). Smoking promoted CRC in a dose-dependent manner in hMSH2 in males (P < 0.05). Females with hMSH2 mutations and both sexes with the hMLH1 groups only demonstrated a smoking effect after an extensive smoking history (P < 0.05).

CONCLUSION: CRC promotion by smoking in HNPCC patients is dependent on gene mutation, gender and age. …


Intersection Safety, Aemal Khattak Mar 2006

Intersection Safety, Aemal Khattak

Nebraska Department of Transportation: Research Reports

The objectives of this project included a study to determine the safety effects of intersection type (unsignalized, signalized, and interchange) on Nebraska expressway intersections, quantification of the safety effects of a Collision Countermeasure System (CCS), and update of the Nebraska Department of Roads (NDOR) expressway intersection guidelines. The CCS is an Intelligent Transportation Systems (ITS) traffic control device to warn drivers of conflicting cross-traffic at rural, non-signalized intersections. The goal was that if found effective, the CCS will become part of the intersection designer’s options for expressway intersection design (other options being an interchange, traffic signals, and traffic control signs). …


Restricted-Zone Requirements For Superpave Mixes Made With Local Aggregate Sources, Yong-Rak Kim Mar 2006

Restricted-Zone Requirements For Superpave Mixes Made With Local Aggregate Sources, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

No abstract provided.


Optimal Management Of Groundwater Over Space And Time, Nicholas Brozovic, David L. Sunding, David Zilberman Jan 2006

Optimal Management Of Groundwater Over Space And Time, Nicholas Brozovic, David L. Sunding, David Zilberman

Daugherty Water for Food Global Institute: Faculty Publications

For nearly half a century, groundwater has been portrayed in the economic literature as a typical common property resource. Numerous studies of groundwater extraction have analyzed the externalities imposed by users on each other. A large body of work offers clear prescriptions in the form of optimal policy instruments, and a similarly large body of work advocates the needlessness of any centralized intervention. Yet existing theoretical models of groundwater extraction implicitly make two strong assumptions about the underlying behavior of the resource. First, the spatial distribution of resource users is assumed to be irrelevant. Second, path-independence of the resource is …


Performance Evaluation Of The Midwest Guardrail System – Update To Nchrp 350 Test No. 3-11 With 28" C.G. Height (2214mg-2), Karla A. Polivka, Ronald K. Faller, Dean L. Sicking, John R. Rohde, Robert W. Bielenberg, John D. Reid Jan 2006

Performance Evaluation Of The Midwest Guardrail System – Update To Nchrp 350 Test No. 3-11 With 28" C.G. Height (2214mg-2), Karla A. Polivka, Ronald K. Faller, Dean L. Sicking, John R. Rohde, Robert W. Bielenberg, John D. Reid

Mid-America Transportation Center: Final Reports and Technical Briefs

Based on the proposed changes to the National Cooperative Highway Research Program (NCHRP) Report No. 350 guidelines, NCHRP Project 22-14(2) researchers deemed it appropriate to evaluate a strong-post W-beam guardrail systems prior to finalizing the new crash testing procedures and guidelines. For this effort, the Midwest Guardrail System (MGS) was selected for evaluation. One full-scale vehicle crash test was performed on the longitudinal barrier system in accordance with the Test Level 3 (TL-3) requirements presented in the Update to NCHRP Report No. 350. For this test, a 2270P pickup truck vehicle, which was a 1⁄2-ton, four-door vehicle with a 711 …


Trees And Ice Storms: The Development Of Ice Storm–Resistant Urban Tree Populations (Second Edition), Richard J. Hauer, Jeffrey O. Dawson, Les P. Werner Jan 2006

Trees And Ice Storms: The Development Of Ice Storm–Resistant Urban Tree Populations (Second Edition), Richard J. Hauer, Jeffrey O. Dawson, Les P. Werner

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Severe ice storms occur every year in the United States and Canada, particularly in the midwestern and eastern regions of the United States. Along with fires and wind, ice storms are a frequent and major natural disturbance factor in eastern deciduous forests. Likewise ice storms are responsible for deaths and injuries of people and cause dramatic damage and tree loss to urban forests. Ice storms annually result in millions of dollars in loss, and potentially billions of dollars in losses for extreme and widespread ice storms. Damage to electric distribution systems, blocked roadways, and property damage from fallen trees and …


Implementation Of The Biological Opinion For The Missouri River Mainstem System, Missouri River Bank Stabilization And Navigation Project, And Kansas River Reservoir System Jan 2006

Implementation Of The Biological Opinion For The Missouri River Mainstem System, Missouri River Bank Stabilization And Navigation Project, And Kansas River Reservoir System

United States Army Corps of Engineers, Omaha District

The Endangered Species Act (ESA) requires that the Corps of Engineers (Corps), in coordination with the appropriate resource agencies, will ensure that any action authorized, funded or carried out is not likely to jeopardize the continued existence of any federally listed threatened or endangered species or result in the destruction or adverse modification of critical habitat. On November 30, 2000, formal consultation between the U.S. Fish and Wildlife Service (USFWS) and the Corps under Section 7 of the ESA culminated with the "Biological Opinion on the Operation of the Missouri River Main Stem System, Operation and Maintenance of the Missouri …


U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, June 2006 Jan 2006

U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, June 2006

United States Army Corps of Engineers, Omaha District

Current Conditions


Water Year 2006 Mountain Snow


Drought Outlook


Ft. Peck, Montana


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Garrison, North Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Boat Ramp Information


Noxious Weeds Overview


Cultural Resources Overview


Other Areas of Interest/Concern


Oahe, South Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Mainstem Reservoir Information, Weekly Elevation Comparison 3 APR 2006 through 24 APR 2006


Mainstem Reservoir Storage Comparison Water Years 2004, 2005, 2006


Ft. Peck, MT


Garrison, ND


Oahe, SD


U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, May 2006 Jan 2006

U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, May 2006

United States Army Corps of Engineers, Omaha District

Current Conditions


Water Year 2006 Mountain Snow


Drought Outlook


Ft. Peck, Montana


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Garrison, North Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Boat Ramp Information


Noxious Weeds Overview


Cultural Resources Overview


Other Areas of Interest/Concern


Oahe, South Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Mainstem Reservoir Information, Weekly Elevation Comparison 3 APR 2006 through 24 APR 2006


Mainstem Reservoir Storage Comparison Water Years 2004, 2005, 2006


Ft. Peck, MT


Garrison, ND


Oahe, SD


U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, October 2006 Jan 2006

U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, October 2006

United States Army Corps of Engineers, Omaha District

Current Conditions


Drought Outlook


Ft. Peck, Montana


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Garrison, North Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Boat Ramp Information


Noxious Weeds Overview


Cultural Resources Overview


Other Areas of Interest/Concern


Oahe, South Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Mainstem Reservoir Information, Weekly Elevation Comparison 7 AUG 2006 through 28 AUG 2006


Mainstem Reservoir Storage Comparison Water Years 2004, 2005, 2006


Ft. Peck, MT


Garrison, ND


Oahe, SD


U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, September 2006 Jan 2006

U.S. Army Corps Of Engineers Omaha District Monthly Drought Report, September 2006

United States Army Corps of Engineers, Omaha District

Current Conditions


Drought Outlook


Ft. Peck, Montana


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Garrison, North Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Boat Ramp Information


Noxious Weeds Overview


Cultural Resources Overview


Other Areas of Interest/Concern


Oahe, South Dakota


Reservoir Elevation Overview


Water Intake Overview


Access Overview


Noxious Weeds Overview


Cultural Resources Overview


Mainstem Reservoir Information, Weekly Elevation Comparison 7 AUG 2006 through 28 AUG 2006


Mainstem Reservoir Storage Comparison Water Years 2004, 2005, 2006


Ft. Peck, MT


Garrison, ND


Oahe, SD


Changes In Manganese And Lead In The Environment And Young Children Associated With The Introduction Of Methylcyclopentadienyl Manganese Tricarbonyl In Gasoline—Preliminary Results, Brian Gulson, Karen Mizon, Alan Taylor, Michael Korsch, Jennifer Stauber, J. Michael Davis, Honway Louis, Michael Wu, Hilton Swan Jan 2006

Changes In Manganese And Lead In The Environment And Young Children Associated With The Introduction Of Methylcyclopentadienyl Manganese Tricarbonyl In Gasoline—Preliminary Results, Brian Gulson, Karen Mizon, Alan Taylor, Michael Korsch, Jennifer Stauber, J. Michael Davis, Honway Louis, Michael Wu, Hilton Swan

United States Environmental Protection Agency: Publications

A 4-year longitudinal study is being conducted to evaluate potential changes to the environment and exposure of young children associated with the introduction of methylcyclopentadienyl manganese tricarbonyl (MMT) into Australia in 2001. The cohort consists of 57 females and 56 males, with an age range of 0.29–3.9 years. Samples are collected every 6 months from children in residences located at varying distances from major traffic thoroughfares in Sydney. Environmental samples include air, house, and daycare center dustfall, soil, dust sweepings, and gasoline; samples from the children include blood, urine, handwipes prior to and after playing outdoors, and a 6-day duplicate …


Assessing Effects Of Alternative Agricultural Practices On Wildlife Habitat In Iowa, Usa, Mary Santelmann, Kathryn Freemark, Jean Sifneos, Denis White Jan 2006

Assessing Effects Of Alternative Agricultural Practices On Wildlife Habitat In Iowa, Usa, Mary Santelmann, Kathryn Freemark, Jean Sifneos, Denis White

United States Environmental Protection Agency: Publications

A habitat-change model was used to compare past, present, and future land cover and management practices to assess potential impacts of alternative agricultural practices on wildlife in two agricultural watersheds, Walnut Creek and Buck Creek, in central Iowa, USA. This approach required a habitat map for each scenario based on soil type and land cover, a list of resident species, and an estimate of the suitability of each of 26 habitat classes for every species. Impact on wildlife was calculated from median percent change in habitat area relative to the present. Habitat classes with the highest species richness for native …


Inter-Habitat Variation In The Benthos Of The Upper Missouri River (North Dakota, Usa): Implications For Great River Bioassessment, Ted Angradi, E. William Schweiger, David Bolgrien Jan 2006

Inter-Habitat Variation In The Benthos Of The Upper Missouri River (North Dakota, Usa): Implications For Great River Bioassessment, Ted Angradi, E. William Schweiger, David Bolgrien

United States Environmental Protection Agency: Publications

We examined inter-habitat variation in benthic macroinvertebrate assemblages in the 180-km Garrison Reach of the Upper Missouri River, North Dakota (USA) in 2001–2003. The Garrison Reach is unchannelized with a mostly rural setting. Flows are regulated by Garrison Dam. We sampled benthos from three habitats defined a priori: channel, shoreline, and backwater. Benthic assemblages were different in each habitat. Average Bray-Curtis dissimilarity in assemblage composition ranged from 89% for backwater versus channel habitat to 70% for backwater versus shoreline habitat. There were distinct intra-habitat groups within a priori habitats: channel assemblages included moving-sand assemblages and other-substrate channel assemblages; backwater assemblages …


Mode Of Action In Relevance Of Rodent Liver Tumors To Human Cancer Risk, Michael P. Holsapple, Henri C. Pitot, Samuel H. Cohen, Alan R. Boobis, James E. Klaunig, Timothy Pastoor, Vicki L. Dellarco, Yvonne P. Dragan Jan 2006

Mode Of Action In Relevance Of Rodent Liver Tumors To Human Cancer Risk, Michael P. Holsapple, Henri C. Pitot, Samuel H. Cohen, Alan R. Boobis, James E. Klaunig, Timothy Pastoor, Vicki L. Dellarco, Yvonne P. Dragan

United States Environmental Protection Agency: Publications

Hazard identification and risk assessment paradigms depend on the presumption of the similarity of rodents to humans, yet species specific responses, and the extrapolation of high-dose effects to lowdose exposures can affect the estimation of human risk from rodent data. As a consequence, a human relevance framework concept was developed by the International Programme on Chemical Safety (IPCS) and International Life Sciences Institute (ILSI) Risk Science Institute (RSI) with the central tenet being the identification of a mode of action (MOA). To perform a MOA analysis, the key biochemical, cellular, and molecular events need to first be established, and the …