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Articles 2521 - 2550 of 3136

Full-Text Articles in Physical Sciences and Mathematics

Uranium-Uranium Collisions At Relativistic Energies, Bao-An Li, Matt Tilley Jan 2001

Uranium-Uranium Collisions At Relativistic Energies, Bao-An Li, Matt Tilley

Journal of the Arkansas Academy of Science

No abstract provided.

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Non-Commercial Software For The Analysis And Interpretation Of High Resolution Molecular Spectra, A. R. Ford, Scott W. Reeve Jan 2001

Non-Commercial Software For The Analysis And Interpretation Of High Resolution Molecular Spectra, A. R. Ford, Scott W. Reeve

Journal of the Arkansas Academy of Science

No abstract provided.

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Empirical Model For The Variarion In Concentration Of Metal Ions During A Precipitation Event, David M. Chittenden Ii, Julie D. Chittenden Jan 2001

Empirical Model For The Variarion In Concentration Of Metal Ions During A Precipitation Event, David M. Chittenden Ii, Julie D. Chittenden

Journal of the Arkansas Academy of Science

The concentration of a pollutant in an air mass and the concentration of that pollutant in a series of rain water samples from a single event within that air mass, fluctuate during the course of the event. This the result of scavenging, diffusion, and advection processes. A simple mathematical model, containing only a scavenging term has had limited success in describing changes of concentration in rain water. To date, no attempt has been made to include diffusion or advection terms in the model. In this study, a two factor model was developed after determining that (1) the exponential scavenging term …

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Life History Of The River Shiner, Notropis Blennius (Cyprinidae), In The Arkansas River Of Western Arkansas, Laura Hudson, Thomas M. Buchanan Jan 2001

Life History Of The River Shiner, Notropis Blennius (Cyprinidae), In The Arkansas River Of Western Arkansas, Laura Hudson, Thomas M. Buchanan

Journal of the Arkansas Academy of Science

The reproductive cycle, food habits, and age and growth of the river shiner, Notropis blennius (Girard), in the Arkansas River of western Arkansas were studied from May 1996 through October 1997. Based on gonadosomatic indices and mean ovumd iameters of females, tubercle development in males, and the first appearance of young-of-year in samples, the breeding season extended from June through August in both 1996 and 1997. The river shiner is a diurnal, generalist feeder that forages on a wide variety of food items. In all four seasons, detritus dominated the diets of adults and juveniles in terms of volume and …

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Geologic Hazards Associated With Shale Strata And Swelling Clays Within Fayetteville Quadrangle, Washington County, Arkansas, Maria E. King, Jack T. King, Stephen K. Boss Jan 2001

Geologic Hazards Associated With Shale Strata And Swelling Clays Within Fayetteville Quadrangle, Washington County, Arkansas, Maria E. King, Jack T. King, Stephen K. Boss

Journal of the Arkansas Academy of Science

No abstract provided.

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Moisture Determination By Thermal Titrimetry Using The Enthalpy Of Reaction Of 2,2-Dimethoxypropane With Water, Edmond W. Wilson Jr., Reagan Baber Jan 2001

Moisture Determination By Thermal Titrimetry Using The Enthalpy Of Reaction Of 2,2-Dimethoxypropane With Water, Edmond W. Wilson Jr., Reagan Baber

Journal of the Arkansas Academy of Science

Assays for water content can be readily and simply carried out using the technique of thermal titrations. The method is based on measuring the endothermic heat of reaction exhibited when 2,2-dimethoxypropane is brought into contact with water in the presence of an acid catalyst. The apparatus is simple, requiring a constant delivery rate buret, a recording thermistor thermometer, and a stirred, thermally insulated reaction container. The 2,2-dimethoxypropane reagent used for the water assays is environmentally friendly ("green"). It is stable, pleasant smelling and economical. Working curves in three solvents, acetonitrile, tetrahydrofuran and 1,4-dioxane, show excellent precision and linearity with increasing …

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Thermodynamic Properties Of Neutron-Rich Matter, Matt Tilley, Bao-An Li Jan 2001

Thermodynamic Properties Of Neutron-Rich Matter, Matt Tilley, Bao-An Li

Journal of the Arkansas Academy of Science

The mechanism of supernova explosion and properties of neutron stars are uniquely determined by the equation of state of neutron-rich matter. Using a phenomenological equation of state within a thermal model, we study thermodynamic properties of neutron-rich matter. In particular, we investigate chemical (diffusive) and mechanical (isothermal) instabilities of neutron-rich matter and their dependence on the nuclear equation of state. Both instabilities are found to be heavily dependent upon the isospin asymmetry, temperature, and density of neutron-rich matter. We show that the boundary of the chemical instability extends farther out into the density-isospin symmetry plane than that of the mechanical …

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Multi-Phase Transport Study Of Relativistic Nuclear Collisions, Bin Zhang, C. M. Ko, Bao-An Li, Ziwei Lin, Subrata Pal Jan 2001

Multi-Phase Transport Study Of Relativistic Nuclear Collisions, Bin Zhang, C. M. Ko, Bao-An Li, Ziwei Lin, Subrata Pal

Journal of the Arkansas Academy of Science

A multi-phase transport model (AMPT) is developed for the study of hot and dense matter produced in relativistic nuclear collisions. This model includes both initial partonic and final hadronic scattering. Using the AMPT model, we study the momentum distributions of charged particles such as protons, antiprotons, pions, and kaons in central heavy ion collisions at Super Proton Synchrotron (SPS) and Relativistic Heavy Ion Collider (RHIC) energies. The results are consistent with experimental data at these energies. They indicate a significant nuclear shadowing but a relative weak jet quenching in the initial dense matter. Antiproton to proton ratio at mid-rapidity increases …

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Plasmid Analysis Of Bacteria That Metabolize The Detergent Igepon, Russell O. Nordeen, Thetsu Mon, David Gilmore Jan 2001

Plasmid Analysis Of Bacteria That Metabolize The Detergent Igepon, Russell O. Nordeen, Thetsu Mon, David Gilmore

Journal of the Arkansas Academy of Science

No abstract provided.

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Synthesis Of A Ruthenium-Tetra(Tht)Dichloride Compound And The Molecular Structure Of The Partially Oxidized Compound Rucl2(Tht)2.2(Tht-O)1.8, L. A. Thornton, Mark Draganjac, Andres Meza, A. W. Cordes Jan 2001

Synthesis Of A Ruthenium-Tetra(Tht)Dichloride Compound And The Molecular Structure Of The Partially Oxidized Compound Rucl2(Tht)2.2(Tht-O)1.8, L. A. Thornton, Mark Draganjac, Andres Meza, A. W. Cordes

Journal of the Arkansas Academy of Science

No abstract provided.

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Synthesis And Characterization Of A Ruthenium-Thioxane Complex, Amanda Wroble, Scotty Sproles, Mark Draganjac, Paul M. Nave Jan 2001

Synthesis And Characterization Of A Ruthenium-Thioxane Complex, Amanda Wroble, Scotty Sproles, Mark Draganjac, Paul M. Nave

Journal of the Arkansas Academy of Science

No abstract provided.

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Upper White River Bmp Implementation Project (Nps Final Report), Paul F. Vendrell, K. F. Steele, M. A. Nelson, R. W. Mcnew Dec 2000

Upper White River Bmp Implementation Project (Nps Final Report), Paul F. Vendrell, K. F. Steele, M. A. Nelson, R. W. Mcnew

Arkansas Water Resources Center Technical Reports

The project objective was to monitor agricultural best management practices implemented to minimize sediment, nutrient, and bacterial impact on water quality of the Upper White River watershed. The project targeted the primary agricultural causes of non-point source nutrient and bacterial pollution in three sub-basins of the White River in the Beaver Lake Watershed. Areas with high animal densities targeted high source areas. High source areas were treated with best management practices (BMP) in an effort to reduce the impact to the White River and Beaver Lake. The predominant BMP implemented was waste management, a component of the farm nutrient management …

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Extended Water Quality Monitoring Of The Lincoln Lake Watershed, Paul F. Vendrell, K. F. Steele, M. A. Nelson, L. W. Cash, R. W. Ncnew Dec 2000

Extended Water Quality Monitoring Of The Lincoln Lake Watershed, Paul F. Vendrell, K. F. Steele, M. A. Nelson, L. W. Cash, R. W. Ncnew

Arkansas Water Resources Center Technical Reports

For seven years, the Lincoln Lake (Moores Creek and Beatty Branch) watershed was monitored for improvements in water quality resulting from agricultural best management practices (BMP) implemented to reduce nutrient transport. During the first three years of monitoring (1991 to 1994), nitrogen transport declined significantly (Edwards et al., 1994, 1996, and 1997) under both base and storm flow conditions. This decline in nitrogen transport was again observed in the three-year period following 1994 (Vendrell et al. 1998). This monitoring effort has demonstrated that water quality bas improved in the Lincoln Lake watershed. However, since the nitrogen transport continued to decline …

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Improving Water Quality Through Bmps For Crop Production Systems Whole Farm Soil And Water Management, J. T. Gilmour, L. R. Frye, N. A. Slaton Dec 2000

Improving Water Quality Through Bmps For Crop Production Systems Whole Farm Soil And Water Management, J. T. Gilmour, L. R. Frye, N. A. Slaton

Arkansas Water Resources Center Technical Reports

The major objective of this demonstration project was to assess the usefulness of Global Positioning Systems/Geographic Information Systems (GPS/GIS), water testing, soil testing and yield monitoring in a whole farm water and soil management plan. An important part of this objective was to make recommendations to increase crop productivity and decrease the potential for surface water degradation through erosion and runoff at the farm. The farm was located on 2400 acres in the Bayou de View watershed in Monroe County, Arkansas. The farm lies approximately five miles southwest of the town of Brinkley straddling Highway 17 just south of its …

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Proceedings Of The Arkansas Water Resources Center Annual Conference: Environmental Hydrology, Kenneth F. Steele Nov 2000

Proceedings Of The Arkansas Water Resources Center Annual Conference: Environmental Hydrology, Kenneth F. Steele

Arkansas Water Resources Center Technical Reports

The papers and abstracts in these proceedings are the result of a joint conference of the Arkansas Water Resources Center (A WRC) with the SouthCentral Section of the Geological Society of America. The joint conference was a success with about 250 participants. A WRC sponsored two sessions on Environmental Hydrology and a short course titled "Hydrogeology and Geochemistry of Salt Water Contamination." The Environmental Hydrology presentations covered wide-ranging topics that reflect the diversity of the environmental settings across Arkansas. Topics ranged from salt water and critical ground water issues in the Delta to endangered species and interbasin ground-water recharge in …

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Investigation Of Optimum Sample Number And Timing For Determining Pollution Loads, T. S. Soerens, Marc A. Nelson Oct 2000

Investigation Of Optimum Sample Number And Timing For Determining Pollution Loads, T. S. Soerens, Marc A. Nelson

Arkansas Water Resources Center Technical Reports

In order to determine the impacts of non point source (NPS) pollution and to develop Total Maximum Daily Loads (Tr\tfDLs), accurate measurements of pollution loads in streams are critical. The objectives of this study were to accurately detemline pollutant loads at two sites by intensive storm sampling, to develop sub-sampling and other data analysis techniques, to detemline the effect of sample interval on load calculation accuracy, and to find the minimum sample interval required to determine storm loads at a required accuracy. The two stream sites used were a 1st order and a 3rd order stream in the Illinois River …

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Spatial And Temporal Changes In Land Use And Land Cover From 1988 To 1992 In The Upper White River Watershed, H. D. Scott, J. M. Mckimmey Sep 2000

Spatial And Temporal Changes In Land Use And Land Cover From 1988 To 1992 In The Upper White River Watershed, H. D. Scott, J. M. Mckimmey

Arkansas Water Resources Center Technical Reports

Changes in Land Use and Land Cover (LULC) in the upper White River Watershed from 1988 to 1992 were analyzed and plotted using the geographic information system known as Geographic Resources Analyses Support System (GRASS). This portion of the White River Watershed includes two sub-basins the East Fork and the Middle Fork. In addition, LULC changes were determined for two smaller sub-basins, Shumate Creek and Cannon Creek, located in the East Fork of the White River. The sources and methods of interpretation of the 1988 and 1992 of data were different. Thus, there were variations in how certain portions of …

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Ground Water In Northwest Arkansas: Minimizing Nutrient Contamination From Non-Point Sources In Karst Terrane, R. K. Davis, J. V. Brahana, J. S. Johnston Sep 2000

Ground Water In Northwest Arkansas: Minimizing Nutrient Contamination From Non-Point Sources In Karst Terrane, R. K. Davis, J. V. Brahana, J. S. Johnston

Arkansas Water Resources Center Technical Reports

The purpose of the project is to evaluate the effectiveness of Best Management Practices (BPMs) in preventing non-point source contamination of the ground-water resources in the karst terrane of northwestern Arkansas. Limestone and dolomite aquifers in the region are highly vulnerable to contamination. Ground-water studies performed in the region during the last two decades indicate degradation of these carbonate aquifers by nutrients and bacteria. The expeditious growth of the poultry industry during this period, in combination with the inordinate population growth of the region constitute a threat to the ground-water resources from both point sources and non-point sources of contamination. …

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Illinois River 1999 Pollutant Loads At Arkansas Higway 59 Bridge, Marc A. Nelson, Thomas S. Soerens Sep 2000

Illinois River 1999 Pollutant Loads At Arkansas Higway 59 Bridge, Marc A. Nelson, Thomas S. Soerens

Arkansas Water Resources Center Technical Reports

Automatic water samplers and aU. S. Geological Survey gauging station were established in 1995 on the main stem of the Illinois River at the Arkansas Highway 59 Bridge. Since that time, continuous stage and discharge measurements and water quality sampling have been used to determine pollutant concentrations and loads in the Arkansas portion of the Illinois River. This report represents the results from the measurement and sampling for January 1, 1999 to December 31, 1999.

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Economics Of Using On-Farm Reservoirs To Distribute Diverted Surface Water To Depleted Ground Water Areas Of The Southern Mississippi Valley Region, Eric J. Wailes, Kenneth B. Young, James Smartt, Gail L. Cramer Aug 2000

Economics Of Using On-Farm Reservoirs To Distribute Diverted Surface Water To Depleted Ground Water Areas Of The Southern Mississippi Valley Region, Eric J. Wailes, Kenneth B. Young, James Smartt, Gail L. Cramer

Arkansas Water Resources Center Technical Reports

Rapid ground water depletion has become a significant problem for parts of the Southern Mississippi River Valley. In 1997, the Arkansas Soil and Water Conservation Commission (ASWCC) declared six counties in the Grand Prairie of Arkansas critical ground water areas. A proposed solution to the ground water depletion problem in this region is to divert surplus flows from the White River by a canal system to the farmer stakeholders. To make the system work, on-farm reservoirs will be needed to store and manage the diverted surface water for crop irrigation use during the growing season.

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Trophic Dynamics And Pollution Effects In Cave Springs Cave, Arkansas, G. O. Graening, Arthur V. Brown Jul 2000

Trophic Dynamics And Pollution Effects In Cave Springs Cave, Arkansas, G. O. Graening, Arthur V. Brown

Arkansas Water Resources Center Technical Reports

No abstract provided.

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Status Survey Of Aquatic Cave Fauna In Arkansas, G. O. Graening, Arthur V. Brown Jul 2000

Status Survey Of Aquatic Cave Fauna In Arkansas, G. O. Graening, Arthur V. Brown

Arkansas Water Resources Center Technical Reports

No abstract provided.

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Pesticide Ground Water Monitoring Project - Phase Vii, Terry Nichols Mar 2000

Pesticide Ground Water Monitoring Project - Phase Vii, Terry Nichols

Arkansas Water Resources Center Technical Reports

No abstract provided.

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Water Resources Issues In The Arkansas Delta, Kenneth F. Steele Jan 2000

Water Resources Issues In The Arkansas Delta, Kenneth F. Steele

Arkansas Water Resources Center Technical Reports

Despite its location in Northwest Arkansas, the Arkansas Water Resources Center (AWRC) is active state-wide. This fact is underscored by the focus of the Center’s session on "Water Resource Issues in the Arkansas Delta" during its recent joint Conference. Water issues in the Delta include declining water tables, salt water intrusion, and water quality (especially suspended sediment, nitrate and pesticides). Presented papers focused on best management practices for cotton production, economics of on-farm reservoirs, chloride content of irrigation water, and landowner education. The AWRC short course was an excellent one on chemical transport in the vadose zone by Dr. Glenn …

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Double Cysteine Mutations In Staphylococcal Nuclease: The Effect Of Artificially Introduced Disulfide Bonds On Protein Structure And Stability, Anna Terry Jan 2000

Double Cysteine Mutations In Staphylococcal Nuclease: The Effect Of Artificially Introduced Disulfide Bonds On Protein Structure And Stability, Anna Terry

Inquiry: The University of Arkansas Undergraduate Research Journal

Since a protein's function depends on its structure, basic research in protein structure facilitates the solution of many practical problems, such as the synthesis of more effective medicines. With this larger goal in sight, the purpose of this research project is to understand better the chemical principles that underlie protein structure and stability. Disulfide bonds are a potentially stabilizing feature of many proteins. They may form between cysteine residues in close proximity to one another if the orientation is favorable. Often found in proteins produced by organisms that grow at high temperatures, disulfide bonds may anchor side chains together, making …

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Hammett Correlations Of The Amide Proton Chemical Shift In A Series Of 1-Tosyl-3-(4-Substituted Phenyl)Ureas, Frank L. Setliff, Melody K. Harrison Jan 2000

Hammett Correlations Of The Amide Proton Chemical Shift In A Series Of 1-Tosyl-3-(4-Substituted Phenyl)Ureas, Frank L. Setliff, Melody K. Harrison

Journal of the Arkansas Academy of Science

No abstract provided.

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Preparation Of An Electrophilic 3-Methylindole Derivative: Difficulties In Forming A Stable, Suitable Material For The Preparation Of Tryptophan, Jason Boggs, Mariah Mcmasters, Robert W. Curley Jr., Michael J. Panigot Jan 2000

Preparation Of An Electrophilic 3-Methylindole Derivative: Difficulties In Forming A Stable, Suitable Material For The Preparation Of Tryptophan, Jason Boggs, Mariah Mcmasters, Robert W. Curley Jr., Michael J. Panigot

Journal of the Arkansas Academy of Science

In an attempt to prepare stereoselectively beta-deuterated tryptophan, N-protected indole-3-methanol compounds were prepared with model studies being done on undeuterated material. Conversion of these compounds to electrophilic species proved exceptionally difficult and resulted in very low yields or recovered starting material only. A summary of the current results utilizing N-tosyl indole-3-methanol will be presented as well as efforts using N-Boc indole-3-methanol.

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An Analysis Of The Theory Of Functions Of One Real Variable, Robert J. Reed Jan 2000

An Analysis Of The Theory Of Functions Of One Real Variable, Robert J. Reed

Inquiry: The University of Arkansas Undergraduate Research Journal

Few undergraduates are aware that the Riemann integral taught in introductory calculus courses has only limited application-essentially this integral can be used only to integrate continuous functions over intervals. The necessity to integrate a broader class of functions over a wider range of sets that arises in many applications motivates the theory of abstract integration and functional analysis. The founder of this theory was the French mathematician Henri Lebesgue, who in 1902 defined the "Lebesgue measure" of subsets of the real line. The purpose of this project is to elucidate the theory of abstract measure spaces and of important spaces …

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Studies Of Tryptophans In Membrane- Spanning "Walp" Peptides By Deuterium Nmr Spectroscopy, Nichole Reed Jan 2000

Studies Of Tryptophans In Membrane- Spanning "Walp" Peptides By Deuterium Nmr Spectroscopy, Nichole Reed

Inquiry: The University of Arkansas Undergraduate Research Journal

WALP pep tides of sequence acetyl-Gly-Trp-Trp-(Leu-Ala)-Trp-Trp-Ala-ethanolamine insert into lipid bilayers as membrane-spanning a-helices and modulate the lipid phase behavior as functions of n and the lipid acyl chain length. A key feature of the WALP peptides is the positioning of tryptophan (Trp) indole rings at the membrane/water interface. For the examples WALP19 with n = 6.5 and WALP23 with n = 8.5, we have labeled individual indoles with deuterium and incorporated the labeled peptides in oriented, hydrated bilayers of Dimyristoyl-phosphatidylcholine (DMPC). Deuterium NMR spectra from these samples show sharp resonances when the membrane normal is aligned either parallel (Beta = …

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Design, Implementation, And Evaluation Of Virtual Interface Architecture For Power Pc Machines, Ben Mckenzie Jan 2000

Design, Implementation, And Evaluation Of Virtual Interface Architecture For Power Pc Machines, Ben Mckenzie

Inquiry: The University of Arkansas Undergraduate Research Journal

The Virtual Interface Architecture (VIA) standard is a low-latency protocol that was designed for use in high-performance networks. VIA improves performance by reducing overhead in messaging. This research has two components. The first part of this research project is the development of a new tool for measuring the performance of a VIA implementation and comparing it to the more traditional high-overhead protocols used on the Internet. The development of the tool represents a significant contribution in and of itself, since the tool has been put into the public domain and will likely become useful by Lima users, both for measuring …

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