Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 60511 - 60540 of 64990

Full-Text Articles in Entire DC Network

The Distribution Of Amphipods In Southeastern Minnesota And Their Relation To Water Quality And Land Use, James A. Muck, Raymond M. Newman Jan 1992

The Distribution Of Amphipods In Southeastern Minnesota And Their Relation To Water Quality And Land Use, James A. Muck, Raymond M. Newman

Journal of the Iowa Academy of Science: JIAS

The distribution of the amphipods Gammarus pseudolimnaeus and Hyalella azteca was determined from 97 designated trout streams in Minnesota, along with temperature, conductivity, and nitrate levels. Streams were classified into 4 land use/geology groups. G. pseudolimnaeus was found in 11 counties and at 123 of 168 sites in 83 of the 97 streams sampled. Hyalella azteca was found in 7 counties at 26 sites m 21 streams. Spearman rank correlations showed a high degree of correlation between nitrate (range: 0-11 mg N/L), conductivity (range: 325-870 μS/cm), and geology. The relative abundance of G. pseudolimnaeus was negatively correlated with nitrate, geology …


13.2.15. Human Disturbances Of Waterfowl: Causes, Effects, And Management, Carl E. Korschgen, Robert B. Dahlgren Jan 1992

13.2.15. Human Disturbances Of Waterfowl: Causes, Effects, And Management, Carl E. Korschgen, Robert B. Dahlgren

Waterfowl Management Handbook

Human disturbances of waterfowl can be intentional or unintentional. They may result from overt or directed activities or may be ancillary to activities not initially thought to be of concern to birds. Some of these disturbances are manifested by alertness, fright (obvious or unapparent), flight, swimming, disablement, or death. Therefore, persons responsible for waterfowl management areas should be aware of the problems from human disturbance and should design management and facilities that increase public appreciation of waterfowl.

In the last 20 years, the intensity of water-based recreation increased drastically, especially on inland waters. Waterfowl are wary, seeking refuge from all …


Wildlife Health Centre Newsletter, Volume 1-1, Winter 1992 Jan 1992

Wildlife Health Centre Newsletter, Volume 1-1, Winter 1992

Canadian Cooperative Wildlife Health Centre: Newsletters and Publications

Canadian Cooperative Wildlife Health Centre is underway!
How the CCWHC will work
How to contact the Centre
The people involved
The logo
Disease update


Overview Of The Symposium On Walleye Stocks And Stocking, Daryl G. Ellison, William G. Franzin Jan 1992

Overview Of The Symposium On Walleye Stocks And Stocking, Daryl G. Ellison, William G. Franzin

Nebraska Game and Parks Commission: Staff Research Publications

Rising angler interest in walleye Stizostedion vitreum, a general decline in natural recruitment in some waters, and increasing demands for stocking have produced a need to evaluate stocking strategies. Such evaluations were the subject of the Walleye Stocks and Stocking Symposium summarized herein. Among walleye stocking evaluations reported in the symposium, 32% of fry stockings, 32% of small-fingerling stockings, and 50% of advanced-fingerling stockings were considered successful. Further improvement in stocking success requires research into the factors that affect survival. Matching stocking times and places to appropriate food resources appears to be a key element in successful introductions of …


Nebraska's Vanishing Species, Greg Wingfield Jan 1992

Nebraska's Vanishing Species, Greg Wingfield

Nebraska Game and Parks Commission: Staff Research Publications

Nebraskans are blessed with a rich heritage - friendly, hard-working people, unique landforms and diverse natural resources, including native species of plants and animals. Unfortunately, an irreplaceable part of this heritage, our threatened and endangered species, is vanishing.
Simply stated, a threatened species is one likely to become endangered. An endangered species is one so rare that it is in danger of becoming extinct. Extinction is the loss of a species from this world.


Spring 1992, Nsu Oceanographic Center Jan 1992

Spring 1992, Nsu Oceanographic Center

Currents

No abstract provided.


A Reconnaissance Study Of Herbicides And Their Metabolites In Surface Water Of The Midwestern United States Using Immunoassay And Gas Chromatography/Mass Spectrometry, E. Michael Thurman, Donald A. Goolsby, Michael Meyer, Margaret Mills, Michael L. Pomes, Dana W. Kolpin Jan 1992

A Reconnaissance Study Of Herbicides And Their Metabolites In Surface Water Of The Midwestern United States Using Immunoassay And Gas Chromatography/Mass Spectrometry, E. Michael Thurman, Donald A. Goolsby, Michael Meyer, Margaret Mills, Michael L. Pomes, Dana W. Kolpin

United States Geological Survey: Staff Publications

Preemergent herbicides and their metabolites, particularly atrazine, deethylatrazine, and metolachlor, persisted from 1989 to 1990 in the majority of rivers and streams in the midwestern United States. In spring, after the application of herbicides, the concentrations of atrazine, alachlor, and simazine were frequently 3-10 times greater than the U.S. Environmental Protection Agency maximum contaminant level (MCL). The concentration of herbicides exceeded the MCLs both singly and in combination. Two major degradation products of atrazine (deisopropylatrazine and deethylatrazine) also were found in many of the streams. The order of persistence of the herbicides and their metabolites in surface water was atrazine …


Wildlife Damage News, Volume 3, Winter 1992 Jan 1992

Wildlife Damage News, Volume 3, Winter 1992

Wildlife Damage News

CONTENTS:
Coons in the Chimney
Excluding Bats from Structures
International Resolution Supports Regulated Trapping
Species Profile - Woodchuck
Wildlife Veterinarians Adopt Position Statement on Oral Rabies Vaccine
NYS Nuisance Wildlife Control Operators Become Organized
A Wildlife Professional Talks About Animal Rights and Animal Welfare
Current Literature
Meetings of Interest
The Northeast Association of Wildlife Damage Biologists


The University Of Iowa Museum Of Natural History: An Historical Perspective, George D. Shrimper Jan 1992

The University Of Iowa Museum Of Natural History: An Historical Perspective, George D. Shrimper

Journal of the Iowa Academy of Science: JIAS

The 132-year record of UIMNH essentially mirrors historical and on-going trends in related institutions. As scholarship grew in the natural sciences during the 19th century, natural history museums became centers for scientific research. A "Golden Age" of museum-based expeditionary work and taxonomic research was marked at UI by the careers of curator/naturalists Calvin, Nutting, Macbride, and Shimek. Systematic biology and paleontology thrived with the accumulation of extensive collections. De-emphasis of "natural history" studies followed after 1920-30 with a concomitant growth in cellular and molecular biology. In seeking new directions and financial support, many museums, including UIMNH, shifted emphasis to public …


Lithium Transport, Mg2+ Competition, And Phospholipid Composition In Human Erythrocytes: A Multinuclear Magnetic Resonance Study, Aida Abraha Jan 1992

Lithium Transport, Mg2+ Competition, And Phospholipid Composition In Human Erythrocytes: A Multinuclear Magnetic Resonance Study, Aida Abraha

Dissertations

No abstract provided.


Spin Label Studies Of Radical Reduction In Normal And Sickle Erythrocyte Membranes Associated With Antioxidants, Yin Zhang Jan 1992

Spin Label Studies Of Radical Reduction In Normal And Sickle Erythrocyte Membranes Associated With Antioxidants, Yin Zhang

Dissertations

No abstract provided.


Annual Report Of The Iowa Academy Of Science, 1991-92, Paul E. Rider Jan 1992

Annual Report Of The Iowa Academy Of Science, 1991-92, Paul E. Rider

Journal of the Iowa Academy of Science: JIAS

Starting in 1976, annual reports have served as a continuing record of the activities of the Iowa Academy of Science. These augment a 100 year history of the Academy which was written in the centennial year of 1975.

This report covers the period from July 1, 1991 to June 30, 1992. It is based on the official records of the Academy (committee reports, Board minutes, correspondence) as well as the recollections, impressions and thoughts of the author.


Bacteriological Water Quality Of Beaver Reservoir, Arkansas, Jimmy D. Bragg, Mark E. Clark Jan 1992

Bacteriological Water Quality Of Beaver Reservoir, Arkansas, Jimmy D. Bragg, Mark E. Clark

Journal of the Arkansas Academy of Science

Beaver Reservoir water quality was determined through enumeration of Total coliforms and Fecal coliforms bacterial parameters at selected locations during 1991. Several areas of the reservoir contained high numbers of indicator bacteria, suggesting excessive fecal contamination. Significant numbers of salmonella-like bacteria were also cultured on SS agar, and several strains were serotyped positive for Salmonella antigens.


Soil Chemistry And Nutrition Of North American Red Spruce-Fir Stands: Evidence For Recent Change, J. D. Joslin, J. M. Kelly, H. Van Miegroet Jan 1992

Soil Chemistry And Nutrition Of North American Red Spruce-Fir Stands: Evidence For Recent Change, J. D. Joslin, J. M. Kelly, H. Van Miegroet

Watershed Sciences Faculty Publications

One set of hypotheses offered to explain the decline of red spruce (Picea rubens Sarg.) in eastern North America focuses on the effect of acidic deposition on soil chemistry changes that may affect nutrient availability and root function. Long-term soils data suggest that soil acidification has occurred in some spruce stands over the past 50 yr, with plant uptake and cation leaching both contributing to the loss of cations. Studies of tree ring chemistry also have indicated changes in Ca/Al and Mg/Al ratios in red spruce wood, suggesting increases in the ionic strength of soil solution. Irrigation studies using strong …


Low-Silica And High-Calcium Stone In The Newman Limestone (Mississippian) On Pine Mountain, Letcher County, Southeastern Kentucky, Garland R. Dever Jr., Thomas L. Robl, Jack R. Moody, Frank H. Walker, George W. Ellsworth Jr., Lance S. Barron Jan 1992

Low-Silica And High-Calcium Stone In The Newman Limestone (Mississippian) On Pine Mountain, Letcher County, Southeastern Kentucky, Garland R. Dever Jr., Thomas L. Robl, Jack R. Moody, Frank H. Walker, George W. Ellsworth Jr., Lance S. Barron

Information Circular--KGS

The coal industry of Kentucky is an important market for limestone. Coal producers use limestone as rock dust for explosion abatement in underground coal mines and as a neutralizing agent in surface-mine reclamation and acid-drainage control. Haulage-road construction and maintenance require crushed stone.

Coal-bearing rocks of Pennsylvanian age in the Eastern Kentucky Coal Field generally do not contain limestones that are sufficiently thick to quarry or mine economically, but in the southeastern part of the coal field, fault movement has brought the Newman Limestone to the surface along Pine Mountain. The Newman was sampled at three sites in Letcher County …


Introduction To Fractal Geometry: Definition, Concept, And Applications, Mary Bond Jan 1992

Introduction To Fractal Geometry: Definition, Concept, And Applications, Mary Bond

Presidential Scholars Theses (1990 – 2006)

It has become evident that fractals are not to be tied down to one compact, Webster-style, paragraph definition. The foremost qualities of fractals include self-similarity and dimensionality. One cannot help but appreciate the aesthetic beauty of computer generated fractal art. Beyond these characteristics, when trying to grasp the idea of fractal geometry, it is helpful to learn about its many applications. Fractal geometry is opening new doors for study and understanding in diverse areas such as science, art, and music. All of these facets of fractal geometry unite to provide an intriguing, and alluring, wardrobe for mathematics to wear, so …


The Effects Of Beaver-Created Wetlands On Surface Water Quality Of Streams And Rivers In Dupage County, Illinois, Brian Conklin Jan 1992

The Effects Of Beaver-Created Wetlands On Surface Water Quality Of Streams And Rivers In Dupage County, Illinois, Brian Conklin

Masters Theses

Dam construction by beavers creates wetlands which have the potential to improve water quality, especially in areas near urban centers. However, beaver dams may also cause flooding problems which can result in the removal of the beaver(s) and the destruction of their dam. A further understanding of how beaver-created wetlands affect water quality will provide additional data which can be utilized in beaver management decisions.

In this study, 41 chemical parameters were examined from water taken above and below beaver-created wetlands that existed in DuPage County, Illinois between May and September 1991. This study was designed to examine the effects …


A Proposal For United States/Polish Collaboration On Energy And The Environment, Carole B. Szpunar Jan 1992

A Proposal For United States/Polish Collaboration On Energy And The Environment, Carole B. Szpunar

Chemistry: Faculty Publications and Other Works

Argonne National Laboratory, a U.S. Department of Energy facility that is operated by the University of Chicago and located southwest of Chicago, Illinois, has proposed a collaborative effort by the United States and Poland to conduct applied research on energy and environmental topics of common interest. Through this collaboration, evaluative studies on energy and environmental assessment issues could be developed and implemented by Argonne and one or more sister institutions in Poland, which could lead to active research, development, and demonstration joint activities. The objective of this initiative is to produce strategies and options for review by Poland's decision makers …


Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer Jan 1992

Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer

Theses and Dissertations

Biological denitrification controls nitrate distribution in the Elk Valley aquifer, which underlies approximately 725 square kilometres of northeastern North Dakota and provides drinking water for farms and rural communities in the area. Increased irrigation has raised concerns over potential contamination from agricultural practices. The purpose of this study was to establish the role of biological denitrification in minimizing concentration and distribution of nitrate and to determine the effect irrigation practices have on groundwater flow and nitrate distribution in the saturated zone.

The aquifer is unconfined and consists of up to 20 metres of glacial outwash and deltaic shale-rich sand deposits. …


Instructional Use Of Computers For Entry-Level Physical Therapy Education In The United States, Edmund M. Kosmahl Jan 1992

Instructional Use Of Computers For Entry-Level Physical Therapy Education In The United States, Edmund M. Kosmahl

CCAC Theses and Dissertations

Little was known about the value of computer assisted instruction (CAl) for entry-level physical therapy (PT) education. Factors that affect implementation and use of CAl in entry-level PT education had not been identified. Because of this paucity of information, decision-making about the implementation and use of CAl in entry-level PT education had been hampered.

This study used mail questionnaire survey methods to find:

  1. The extent of use of computer-assisted instruction (CAl) in entry-level physical therapy (PT) education.
  2. The perceived value of CAl compared to more traditional instructional methods for entry-level PT education.
  3. What factors affect implementation and use of CAl …


The Eukaryotic Initiation Factor 2-Associated 67-Kda Polypeptide (P67) Plays A Critical Role In Regulation Of Protein Synthesis Initiation In Animal Cells, Manas K. Ray, Bansidhar Datta, Arup Charkraborty, Ansuman Chattopadhyay, Susanne Meza-Keuthen, Naba K. Gupta Jan 1992

The Eukaryotic Initiation Factor 2-Associated 67-Kda Polypeptide (P67) Plays A Critical Role In Regulation Of Protein Synthesis Initiation In Animal Cells, Manas K. Ray, Bansidhar Datta, Arup Charkraborty, Ansuman Chattopadhyay, Susanne Meza-Keuthen, Naba K. Gupta

Department of Chemistry: Faculty Publications

The eukaryotic initiation factor 2 (eIF-2)- associated 67-kDa polypeptide (p67) isolated from reticulocyte lysate protects the eIF-2 α subunit from eIF-2 kinase-catalyzed phosphorylation and promotes protein synthesis in the presence of active eIF-2 kinases. We have now studied the roles of p67 and eIF-2 kinases in regulation of protein synthesis using several animal cell lysates and an animal cell line (KRC-7) in culture under various growth conditions. The results are as follows. (i) Both p67 and eIF-2 kinase(s) are present in active forms in all animal cells under normal growth conditions and p67 …


Science On The Great Plains: The History Of Physics And Astronomy At The University Of Nebraska-Lincoln, M. Eugene Rudd Jan 1992

Science On The Great Plains: The History Of Physics And Astronomy At The University Of Nebraska-Lincoln, M. Eugene Rudd

M. Eugene Rudd Publications

The year 1988 marked the 100th anniversary of the founding of the Department of Physics at the University of Nebraska. While the year passed without fanfare in the department, DuaneJaecks, one of the members of the faculty, suggested to the author that it would be a good time to write a history of what is now the Department of Physics and Astronomy. He not only provided the initial impetus for the project, but has also given it his continual help and encouragement. While the initial plan was to write only a brief, informal departmental history, the project, like Topsy, grew. …


A Comparison Of Text And Graphics As Effective User Interfaces In A Proposed Advanced Train Control System, Kenneth A. Organes Jan 1992

A Comparison Of Text And Graphics As Effective User Interfaces In A Proposed Advanced Train Control System, Kenneth A. Organes

UNF Graduate Theses and Dissertations

This study tested the effectiveness of three screen interface formats for use in a proposed on-board computer to be used as part of an advanced train control system. One of the three formats contained only graphic depictions of the data, one contained only textual representations and the third had a mixture of graphic and textual data.

Twenty-eight subjects with varying railroad experience were recruited for the experiment. They were divided into three groups, each of which was presented with a simulation using one of the three interface types. The simulations depicted possible engine, track and train conditions that might be …


Removal Of Mercury From Waste Water: Large-Scale Performance Of An Ion Exchange Process, James A. Ritter, J. P. Bibler Jan 1992

Removal Of Mercury From Waste Water: Large-Scale Performance Of An Ion Exchange Process, James A. Ritter, J. P. Bibler

Faculty Publications

Duolite™ GT-73 ion exchange resin routinely reduces the mercury content of a waste water stream to less than the permitted level of 10 ppb. Effluent concentrations from the ion exchange facility (IEF) are consistently between 1 to 5 ppb, even though the feed contains a varying concentration of mercury (0.2 to 70 ppm). Two operational problems have been encountered at that facility, however. Firstly, the stated capacity of the resin for mercury was not being achieved. The abnormally low capacity was traced to analytical laboratory waste which was intermittently treated by the resin. That waste contained hydrochloric acid, stannous chloride, …


Desorption Hysteresis In Five Ion Exchanged Montmorillonites, Jerry Paul Fairley Jan 1992

Desorption Hysteresis In Five Ion Exchanged Montmorillonites, Jerry Paul Fairley

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is generally believed that the formation of recalcitrant (slowly desorbing) fractions of volatile organic compounds (VOCs) in soils is due to diffusion of compounds to sorption sites inaccessible to bulk fluid. The exact nature of these sites, however, is not well understood. In clay minerals, researchers favor two probable areas for the storage of persistent contamination; sites between the clay lamella, or sites with clay particle aggregates.


To test the hypothesis that recalcitrant fractions are formed in interlamellar spaces, a Na/Ca Montmorillonite (Smectite) was ion exchanged with five different cations (K+, Na+, Ca+, …


Using Physical, Chemical And Biological Indicators To Assess Water Quality On The Ouachita National Forest Utilizing Basin Area Stream Survey Methods, J. Alan Clingenpeel, Betty G. Cochran Jan 1992

Using Physical, Chemical And Biological Indicators To Assess Water Quality On The Ouachita National Forest Utilizing Basin Area Stream Survey Methods, J. Alan Clingenpeel, Betty G. Cochran

Journal of the Arkansas Academy of Science

The Ouachita National Forest (ONF) has developed a series of Best Management Practices (BMP's) designed to protect water quality and associated beneficial uses (fisheries, municipal water supplies, etc.). A monitoring program is necessary to document the effectiveness of that protection. The Basin Area Stream Survey (BASS) methodology provides a monitoring link from BMP's to the aquatic ecosystems. The goal of BASS is to identify the physical, chemical and biological characteristics of a stream in a format that will allow comparisons with other streams, and indicate when a stream is being impacted. Six index streams within two ecoregions were selected and …


Table Of Contents, Volume Three, Number One, Winter 1992, Risk Editorial Board Jan 1992

Table Of Contents, Volume Three, Number One, Winter 1992, Risk Editorial Board

RISK: Health, Safety & Environment (1990-2002)

Table of contents for the journal Risk: Issues in Health & Safety (ISSN: 1073-8673).


Modeling Flow And Flood-Plain Storage In A Tidally Affected River, A. G. Strickland, Jerad D. Bales Jan 1992

Modeling Flow And Flood-Plain Storage In A Tidally Affected River, A. G. Strickland, Jerad D. Bales

United States Geological Survey: Staff Publications

A one-dimensional, unsteady-flow model was calibrated, validated, and tested for a 30.4-mile reach of the tidally affected Roanoke River, North Carolina. The model includes a storage reservoir to represent the two-dimensional processes associated with flood-plain storage and release in the one-dimensional flow model. Simulated and measured water levels differed by less than 0.5 foot, and the average absolute difference between simulated and measured flows was 7 percent.


Track Structure Model For Damage To Mammalian Cell Cultures During Solar Proton Events, Francis A. Cucinotta, J. W. Wilson, L. W. Townsend, J. L. Shinn, Robert Katz Jan 1992

Track Structure Model For Damage To Mammalian Cell Cultures During Solar Proton Events, Francis A. Cucinotta, J. W. Wilson, L. W. Townsend, J. L. Shinn, Robert Katz

Robert Katz Publications

Solar proton events (SPEs) occur infrequently and unpredictably, thus representing a potential hazard to interplanetary space missions. Biological damage from SPEs will be produced principally through secondary electron production in tissue, including important contributions due to delta rays from nuclear reaction products. We review methods for estimating the biological effectiveness of SPEs using a high energy proton model and the parametric cellular track model. Results of the model are presented for several of the historically largest flares using typical levels and body shielding.


Comment On Ncrp Report No. 104, "The Relative Biological Effectiveness Of Radiations Of Different Quality", Robert Katz Jan 1992

Comment On Ncrp Report No. 104, "The Relative Biological Effectiveness Of Radiations Of Different Quality", Robert Katz

Robert Katz Publications

The validity of a linear extrapolation to lowest fluences of charged particles demands that the transit of a single charged particle through the target volume is capable of inducing the chain of events leading to an observable end-point. This is always the case for one-hit detectors. It is not always the case for biological cells and tissues (Katz and Hofmann 1982).
By way of example, Cole ct al. (1980) found that, on average, some 500 electrons pass into the nucleus of a CHO cell for inactivation. Similarly, Warters et al. (1977) found that some 500 tritium decays in the nucleus …