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Articles 1861 - 1890 of 2433

Full-Text Articles in Physical Sciences and Mathematics

Microlevel Climate Change Due To Changes In Surface Features In The Ganges Delta, M. M. Adel Jan 1999

Microlevel Climate Change Due To Changes In Surface Features In The Ganges Delta, M. M. Adel

Journal of the Arkansas Academy of Science

The Ganges had been the world's 8th largest river in terms of the volume of water discharge of 490 km3/yr to the ocean 4 prior to 1975. Since that time, over a period of two decades, India has reduced the Ganges discharge through Bangladesh to 40% from its original annual average discharge of 1,932+7-223 m3 /s by diverting water for irrigation in her upper states. The , resulting consequences have been disastrous due to the depletion of the surface water resources. One of the devastating consequences has been the generation of extreme climate. The summertime maximum temperature has risen to …

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Morphometry And Limnology Of Ferguson Lake, Saline County, Arkansas, John D. Rickett, E. P. (Perk) Floyd Jan 1999

Morphometry And Limnology Of Ferguson Lake, Saline County, Arkansas, John D. Rickett, E. P. (Perk) Floyd

Journal of the Arkansas Academy of Science

To more fully understand Ferguson Lake as an ecosystem and eventually relate its water quality and production potential to fisheries management, several limnological variables were sampled monthly from April 1997 through March 1999. Vertical profiles of temperature and dissolved oxygen were recorded, and water samples from 0.5 m. depth were tested for turbidity, pH, total alkalinity, total hardness, ortho-phosphate, nitrate-nitrogen, sulfate, iron and specific conductance. Evaporation rate experiments, spillway discharge and rainfall records were used to estimate lake hydrology. Depth transects on the lake and USGS topographic maps were used to measure and calculate morphometric and watershed features. The lake …

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Changes In Soil Chemistry Beneath Exposed Poultry House Pads And Manure Storage Areas, Stanley L. Chapman, William R. Teague Jan 1999

Changes In Soil Chemistry Beneath Exposed Poultry House Pads And Manure Storage Areas, Stanley L. Chapman, William R. Teague

Journal of the Arkansas Academy of Science

Concerns about nitrates in private drinking water supplies in the older poultry growing areas of Arkansas prompted soil and water testing in the early 1990's. Exposed poultry house pads were recognized as a potential source of nitrates in the groundwater. Soils beneath nine different poultry house pads in five counties were sampled in 10-30 cm increments to bedrock or to a maximum sampling depth of 90 cm. The nine sites had been exposed to natural weathering conditions ranging from never to for more than 20 years. Routine soil tests were conducted by the University of Arkansas Soil Testing Lab at …

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Comparison Of Environmental Assessments Of Two Proposed Harbor Expansions On The Mississippi River, Richard S. Grippo, Bobby Bennett, Randel T. Cox Jan 1999

Comparison Of Environmental Assessments Of Two Proposed Harbor Expansions On The Mississippi River, Richard S. Grippo, Bobby Bennett, Randel T. Cox

Journal of the Arkansas Academy of Science

The National Environmental Policy Act of 1969 requires federally funded projects to be evaluated for environmental impact to determine if a complete environmental impact statement must be prepared. Such an environmental assessment must also be included in any feasibility study for harbor enlargement and bank stabilization measures under the Water Resources Development Act. Population increases, coupled with economic growth from increased agricultural and industrial productivity, have resulted in increased Mississippi River barge transportation needs for Arkansas and Missouri. We report here two such environmental assessments of planned harbor expansions of the New Madrid County and Pemiscot County ports in the …

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Effects Of Predation On Two Species Of Stream-Dwelling Crayfish (Orconectes Marchandi And Cambarus Hubbsi) In Pool And Riffle Microhabitats, Heidi Dukat, Daniel D. Magoulick Jan 1999

Effects Of Predation On Two Species Of Stream-Dwelling Crayfish (Orconectes Marchandi And Cambarus Hubbsi) In Pool And Riffle Microhabitats, Heidi Dukat, Daniel D. Magoulick

Journal of the Arkansas Academy of Science

Community structure may be governed by many abiotic and biotic factors. Of the biotic factors, predation is often considered to be critical in structuring freshwater stream communities. In the Warm Fork of the Spring River, the crayfish Cambarus hubbsi is found mainly in riffles, whereas the crayfish Orconectes marchandi is found in high numbers in pools. We hypothesized that predation, mainly by fish, is a factor causing this segregation. Higher predation rates for C. hubbsi than 0. marchandi in the pools and higher predation rates for 0. marchandi than C. hubbsi in the riffles were expected. A transplant tethering experiment …

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Synthesis And Molecular Structure Of [Cpru(Pph3)(Pms)2]Otf1.3/4 C2>H4C12, Paul M. Nave, Mark Draganjac, A. W. Cordes, Tosha M. Barclay Jan 1999

Synthesis And Molecular Structure Of [Cpru(Pph3)(Pms)2]Otf1.3/4 C2>H4C12, Paul M. Nave, Mark Draganjac, A. W. Cordes, Tosha M. Barclay

Journal of the Arkansas Academy of Science

No abstract provided.

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Speed Range For Breakdown Waves, Mostafa Hemmati, Eric L. George, Frances Terry Jan 1999

Speed Range For Breakdown Waves, Mostafa Hemmati, Eric L. George, Frances Terry

Journal of the Arkansas Academy of Science

Considering the electrons as the main element in breakdown wave propagation and using a one-dimensional, steady-state, three-fluid, hydrodynamical model, previous investigations have resulted in the completion of a set of equations for conservation of mass, momentum, and energy. We will use the terms proforce and antiforce waves, depending on whether the applied electric field force on electrons is with or against the direction of wave propagation. In the case of antiforce waves, the electron gas temperature and therefore the electron fluid pressure is assumed to be large enough to sustain the wave propagation down the discharge tube. For strong discontinuity …

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Statistical Analysis Of Climatic Variables In The Arkansas-Red River Basin, Felix Tendeku Jan 1999

Statistical Analysis Of Climatic Variables In The Arkansas-Red River Basin, Felix Tendeku

Journal of the Arkansas Academy of Science

Surface meteorological data for the Arkansas-Red River basin are analyzed in order to provide statistical data for modeling and simulation of climatic trends within the basin. The variables studied are the ambient temperature, temperature range and precipitation. Daily and monthly mean values, spatial and seasonal variations, and frequency distributions are determined.

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Analysis Of Phytoestrogens By High Performance Liquid Chromatography, Anne A. Grippo, Yan Xie, Benjamin L. Rougeau, William V. Wyatt Jan 1999

Analysis Of Phytoestrogens By High Performance Liquid Chromatography, Anne A. Grippo, Yan Xie, Benjamin L. Rougeau, William V. Wyatt

Journal of the Arkansas Academy of Science

Phytoestrogens are biochemicals synthesized in plants which mimic steroidal estrogen activity in mammals. Analysis of these compounds in the legumes which produce them and in body fluids is important to the study of their physiological effects. High pressure liquid chromatography (HPLC) has been found to be an efficient and sensitive method of identification and quantitation of isoflavonoids, one class of phytoestrogen. Here we report the separation of three isoflavonoids, biochanin A, genistein and daidzein using an HPLC system with a Cg reverse phase column and a linear gradient mobile phase containing acetonitrile and acetic acid/water (10/90, v/v) over 60 minutes. …

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Completion Report: Arkansas State Plant Board Pesticide Ground Water Monitoring Project - Phase Vi, T. Nichols, P. Vendrell, K. Steele, H. D. Scott, C. Armstrong Nov 1998

Completion Report: Arkansas State Plant Board Pesticide Ground Water Monitoring Project - Phase Vi, T. Nichols, P. Vendrell, K. Steele, H. D. Scott, C. Armstrong

Technical Reports

No abstract provided.

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Field Trip Guide: Illinois River Summary, National Poultry Water Management Symposium, Kenneth F. Steele Oct 1998

Field Trip Guide: Illinois River Summary, National Poultry Water Management Symposium, Kenneth F. Steele

Technical Reports

No abstract provided.

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Storm And Base Flow Water Quality For Bear, Calf And Tomahawk Creeks, Kenneth F. Steele, David N. Mott Oct 1998

Storm And Base Flow Water Quality For Bear, Calf And Tomahawk Creeks, Kenneth F. Steele, David N. Mott

Technical Reports

Appendices for MSC 255

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Storm And Base Flow Water Quality For Bear, Calf, And Tomahawk Creeks, Kenneth F. Steele, David N. Mott Oct 1998

Storm And Base Flow Water Quality For Bear, Calf, And Tomahawk Creeks, Kenneth F. Steele, David N. Mott

Technical Reports

Because of the conversion of 92,780 acres of forest to pasture land in the Buffalo River watershed over a 27 year period, there is concern about the affect of agricultural activities on the water quality of the river. Three tributaries (Bear, Calf and Tomahawk creeks) located about mid-length of the Buffalo River were chosen to investigate the affect of agricultural activity on water quality because these streams provide the greatest amounts of fecal bacteria, nitrate+nitrite and phosphorus to the river, despite comprising only 13% of the watershed.

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Quality Of Surface And Ground Water And Best Management Practices, Kenneth F. Steele Sep 1998

Quality Of Surface And Ground Water And Best Management Practices, Kenneth F. Steele

Technical Reports

Arkansas is fortunate to have outstanding water resources, especially in terms of water quality. However, this is not to say that there are no problems. The Arkansas Water Resources Center (AWRC) in cooperation with other state and federal agencies is characterizing our water resources and providing data important to the wise use of these resources. One wise use of our water resources is to mitigate the impact of non-point sources of pollution on water quality through the use of best management practices. These proceedings address not only the characterization of the quality of ground and surface water but also address …

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Vulnerability And Use Of Ground And Surface Waters In The Southern Mississippi Valley Region, H. D. Scott Sep 1998

Vulnerability And Use Of Ground And Surface Waters In The Southern Mississippi Valley Region, H. D. Scott

Technical Reports

There is a concern in the Southern Mississippi River Valley of the United States over non-point source pollution of ground and surface waters resulting from activities associated with agricultural production. This agriculturally intensive region consists of two major land resource areas (MLRAs): Southern Mississippi Valley Silty Uplands (MLRA 134) and the Southern Mississippi Valley Alluvium (MLRA 131). Both MLRAs have level to undulating and rolling topography, relatively fertile soils and a climate particularly conducive for row crop production.

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Vulnerability And Use Of Ground And Surface Waters In The Southern Mississippi Valley Region, H. Don Scott Sep 1998

Vulnerability And Use Of Ground And Surface Waters In The Southern Mississippi Valley Region, H. Don Scott

Technical Reports

There is a concern in the Southern Mississippi River Valley of the United States over non-point source pollution of ground and surface waters resulting from activities associated with agricultural production. This agriculturally intensive region consists of two major land resource areas (MLRAs): Southern Mississippi Valley Silty Uplands (MLRA 134) and the Southern Mississippi Valley Alluvium (MLRA 131). Both MLRAs have level to undulating and rolling topography, relatively fertile soils and a climate particularly conducive for row crop production.

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Llinois River 1997 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, Thomas S. Soerens Sep 1998

Llinois River 1997 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, Thomas S. Soerens

Technical Reports

Automatic water samplers and a USGS 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, 1997 to December 31, 1997.

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Directory Of Water Related Courses Offered At Colleges And Universities In Arkansas As Of November 1998, Kenneth F. Steele Sep 1998

Directory Of Water Related Courses Offered At Colleges And Universities In Arkansas As Of November 1998, Kenneth F. Steele

Technical Reports

This publication lists the water and water-related courses at several universities and colleges in Arkansas as reported during the Fall of 1 998. It is anticipated that users of this directory will extend beyond college students, and will include professionals seeking continuing education, and professors desiring to exchange Information on courses. This directory is not an "absolute" source of water and water-related courses because all of the higher learning Institutions In Arkansas are not listed, and, secondly, because the definition of "water and water-related" varies from institution to institution. None-the-less this directory provides a very valuable and impressive reference on …

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Agricultural Water Management In The Missippi Delta Region Of Arkansas, H. Don Scott, James A. Ferguson, Linda Hanson, Todd Fugitt, Earl Smith Aug 1998

Agricultural Water Management In The Missippi Delta Region Of Arkansas, H. Don Scott, James A. Ferguson, Linda Hanson, Todd Fugitt, Earl Smith

Research Reports and Research Bulletins

Agriculture is the largest use of soil and water resources in eastern Arkansas. This bulletin summarized the recent historical use of soil and water by agriculture and the impact of irrigation on yields of rice, soybeans and cotton. The experiments conducted in the field to quantitatively schedule irrigations of crops are summarized. The results show the close relationship between the irrigation of crops and the extraction of water from the Alluvial Aquifer. The implications of this relationaship for the future are discussed.

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Monitoring Cavefish Populations And Environmental Quality In Cave Springs Cave, Arkansas, Arthur V. Brown, G. O. Graening, Paul Vendrell Aug 1998

Monitoring Cavefish Populations And Environmental Quality In Cave Springs Cave, Arkansas, Arthur V. Brown, G. O. Graening, Paul Vendrell

Technical Reports

Cave Springs Cave, Benton County, Arkansas, was monitored from October 1997 to June 1998 to determine the chemical and physical environmental quality and the status of the population of threatened Ozark cavefish, Amblyopsis rosae. The majority of the chemical parameters measured were indicative of adequate environmental quality in the Cave Springs Cave ecosystem. However, several significant problems were revealed. A trend analysis of known water quality studies of this cave complex suggests that many organic and inorganic chemicals have increased in concentration in the last 14 years. This ecologically sensitive water body did not meet Arkansas water quality regulations for …

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Arkansas Soil Fertility Studies 1997, Wayne E. Sabbe Apr 1998

Arkansas Soil Fertility Studies 1997, Wayne E. Sabbe

Arkansas Agricultural Experiment Station Research Series

No abstract provided.

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Inventory And Characterization Of The Riparian Zone Of The Current And Jacks Fork Rivers, Jonathan Lyon, Cynthia L. Sagers Mar 1998

Inventory And Characterization Of The Riparian Zone Of The Current And Jacks Fork Rivers, Jonathan Lyon, Cynthia L. Sagers

Technical Reports

The ecological, recreational, and economic value of the 134 mile (216 km) riparian corridor within the Ozark National Scenic Riverways (ONSR) is of great interest to land managers and conservationists. Recent interest in applying ecosystem management to forest systems has necessitated a fresh look at the tools and methods in use to assess existing patterns of plant community structure and diversity. The purpose and objective of the study described in this report was to initiate a series of vegetation studies that could be integrated with existing research and management infonnation on the riparian vegetation in the ONSR. Defining the compositional …

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Speed Cut-Off Point For Antiforce Waves, Mostafa Hemmati, Mathues Shane Doss, Eric L. George Jan 1998

Speed Cut-Off Point For Antiforce Waves, Mostafa Hemmati, Mathues Shane Doss, Eric L. George

Journal of the Arkansas Academy of Science

A one-dimensional, three-component, fluid model has been employed to investigate the existence of a speed cut-off point for antiforce breakdown waves. The term antiforce wave is used to identify breakdown waves for which the electric field force on electrons is in the opposite direction of wave propagation. The electron fluid-dynamical equations for antiforce waves are different from those of proforce waves. This presentation will address the difference in the set of equations for proforce and antiforce waves and the method of integration of the set of equations through the dynamical transition region for antiforce waves. Also, for antiforce waves, the …

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Continuous Monitoring Of Star's Main Time Projection Chamber, Wilfred J. Braithwaite, Edwin S. Braithwaite Jan 1998

Continuous Monitoring Of Star's Main Time Projection Chamber, Wilfred J. Braithwaite, Edwin S. Braithwaite

Journal of the Arkansas Academy of Science

STAR refers to the Solenoidal Tracking instrument At RHIC (the Relativistic Heavy Ion Collider). For momenta above 500 MeV/c charged kaons are not separated from pions within STAR's Main TPC (Time Projection Chamber) by track density alone and they are poorly separated below 500 MeV/c, even when using information from other sources like the vertex tracker. Within the TPC large numbers of kaons and pions decay into muons (and undetected neutrinos). Earlier work has shown parent pions and kaons whose decays are detected within a TPC may be distinguished uniquely from each other in a two-dimensional plot of muon-emission angle …

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Analysis Of A Mixture Of Several Dihalonicotinic Acids By Gas Chromotography And Gas Chromotography-Mass Spectrometry, Cheryl L. Fossler, Frank L. Setliff, Ali U. Shaikh Jan 1998

Analysis Of A Mixture Of Several Dihalonicotinic Acids By Gas Chromotography And Gas Chromotography-Mass Spectrometry, Cheryl L. Fossler, Frank L. Setliff, Ali U. Shaikh

Journal of the Arkansas Academy of Science

Six 2,5- and 5,6- dihalonicotinic acids in a mixture were converted to their corresponding methyl esters and then analyzed by gas chromatography and gas chromatography-mass spectrometry. Four methods of conversion were compared for their GC sensitivity, efficiency and analysis time. In Method #1, using HC1 and methanol as the reagents, the displacement of the halogens by chlorine (from HC1) at 2- and 6-positions was a common occurrence, rendering the method inefficient. In Method #2 (BF3/methanol), the displacement of halogens by methoxide was evident. Method #3 (dicyclohexylcarbodiimide/methanol) produced a mixture of derivatives with a poor yield. Method #4 (diazomethane) gave a …

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Preparation Of Methyl 5-Chloro-6-Fluoronicotinate By Fluoride-Chloride Exchange, Frank L. Setliff, Leslie B. Coop Jan 1998

Preparation Of Methyl 5-Chloro-6-Fluoronicotinate By Fluoride-Chloride Exchange, Frank L. Setliff, Leslie B. Coop

Journal of the Arkansas Academy of Science

No abstract provided.

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Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer Jan 1998

Description Of The Sections And Subsections Of The Interior Highlands Of Arkansas And Oklahoma, Thomas L. Foti, George A. Bukenhofer

Journal of the Arkansas Academy of Science

Sections and subsections of the Interior Highlands of Arkansas and Oklahoma are redefined, mapped and briefly summarized. The map was produced to support the Ozark- Ouachita Highlands Assessment (OOHA), being conducted by the USDA Forest Service. It revises the USDA Forest Service map "Ecological units of the eastern United States, first approximation" by Keys et al. (1995) and the earlier maps of the natural divisions of Arkansas (Foti, 1974; Foti, 1976; Pell, 1983) to reflect new knowledge and to achieve consistency with units recognized in Missouri. Four sections (natural divisions) are defined as opposed to the three of the previous …

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Mud Creek Urban Nonpoint Source Demonstration, Paul Vendrell, K. Teague Jan 1998

Mud Creek Urban Nonpoint Source Demonstration, Paul Vendrell, K. Teague

Technical Reports

Northwest Arkansas is the seventh fastest developing area in the nation. The conversion of rolling pastureland into paved city streets, parking lots, and buildings within this rapidly urbanizing region is reducing infiltration and intensifying stormwater runoff. In the city of Fayetteville alone, the population increased from 42,099 to 58,163 between 1990 and 1999, moving the city across the population threshold which will require the Phase II Stormwater Permit process. Approximately half of Fayetteville is included in the Illinois River Watershed, which has been identified as the third highest priority watershed in need of restoration in the state of Arkansas. Mud …

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Infrared Diode Laser Spectrometer For The Study Of Jet Cooled Gases, Anthony Bednar, Eric Barnett, Candace Lindsay, Trey Heath, Philip Williams, Mark Draganjac, Scott W. Reeve Jan 1998

Infrared Diode Laser Spectrometer For The Study Of Jet Cooled Gases, Anthony Bednar, Eric Barnett, Candace Lindsay, Trey Heath, Philip Williams, Mark Draganjac, Scott W. Reeve

Journal of the Arkansas Academy of Science

We have constructed a tunable, high resolution, infrared diode laser spectrometer and combined it with a pulsed supersonic jet expansion. A modified version of the Perry multipass cell has been incorporated into the spectrometer to increase the effective absorption path length. Performance capabilities of the spectrometer are evaluated by examining ro-vibrational spectra for the carbon monoxide molecule in the five micron region of the infrared. From these measurements, an instrumental absorption sensitivity is determined. Finally, since one of our immediate goals is the infrared study of jet cooled transition metal carbonyls, we present high resolution data obtained by entraining the …

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Applying Binomial Statistics To Weighted Monte Carlo, Sue Ellen Mccloskey, William C. Hall, Wilfred J. Braithwaite Jan 1998

Applying Binomial Statistics To Weighted Monte Carlo, Sue Ellen Mccloskey, William C. Hall, Wilfred J. Braithwaite

Journal of the Arkansas Academy of Science

Weighted Monte Carlo calculations requiring a uniform sampling of the problem-space can suffer from diminished statistical significance because many, if not most, of the randomly-chosen sampling points contribute only slightly to the desired result. Their contribution is reduced in size due the variable-size of the weighting terms. In contrast, none of the randomly-chosen points which are favored by variable size weighting terms will have their statistical significance enhanced beyond that of just one random point in the Monte Carlo sampling. A Monte Carlo analysis was used in earlier work to verify both Gauss' Law and Newton's Shell Theorem. Both examples …

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