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Physical Sciences and Mathematics

University of Arkansas, Fayetteville

2016

Articles 31 - 37 of 37

Full-Text Articles in Life Sciences

Experimental And Computational Studies Of Cortical Neural Network Properties Through Signal Processing, Wesley Patrick Clawson May 2016

Experimental And Computational Studies Of Cortical Neural Network Properties Through Signal Processing, Wesley Patrick Clawson

Graduate Theses and Dissertations

Previous studies, both theoretical and experimental, of network level dynamics in the cerebral cortex show evidence for a statistical phenomenon called criticality; a phenomenon originally studied in the context of phase transitions in physical systems and that is associated with favorable information processing in the context of the brain. The focus of this thesis is to expand upon past results with new experimentation and modeling to show a relationship between criticality and the ability to detect and discriminate sensory input. A line of theoretical work predicts maximal sensory discrimination as a functional benefit of criticality, which can then be characterized …

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Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon May 2016

Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon

Graduate Theses and Dissertations

The accurate estimation of soil erosion by the Revised Universal Soil Loss Equation version 2 (RUSLE2) is critical for several conservation assessments, least of which is its use in the Phosphorus Index (PI) to identify and rank the vulnerability of agricultural fields to phosphorus (P) runoff. Earlier versions of RUSLE reported a soil loss overestimation, which were revised to give RUSLE2, where biomass production in different climatic regions was more accurately represented. RUSLE version 2.0, which contains the new vegetative biomass production routine, was evaluated using two performance indices, the Nash Sutcliffe Efficiency Index (NSE) and Index of Agreement (D) …

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Wayne E. Sabbe Arkansas Soil Fertility Studies 2015, Nathan A. Slaton Mar 2016

Wayne E. Sabbe Arkansas Soil Fertility Studies 2015, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.

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Journal Of The Arkansas Academy Of Science - Volume 70 2016, Academy Editors Jan 2016

Journal Of The Arkansas Academy Of Science - Volume 70 2016, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

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Water-Quality Effects On Phytoplankton Species And Density And Trophic State Indices At Big Base And Little Base Lakes, Little Rock Air Force Base, Arkansas, June Through August, 2015, L. J. Driver, B. G. Justus Jan 2016

Water-Quality Effects On Phytoplankton Species And Density And Trophic State Indices At Big Base And Little Base Lakes, Little Rock Air Force Base, Arkansas, June Through August, 2015, L. J. Driver, B. G. Justus

Journal of the Arkansas Academy of Science

Big Base and Little Base Lakes are located on Little Rock Air Force Base, Arkansas, and their close proximity to a dense residential population and an active military/aircraft installation make the lakes vulnerable to water-quality degradation. The U.S. Geological Survey (USGS) conducted a study from June through August 2015 to investigate the effects of water quality on phytoplankton species and density and trophic state in Big Base and Little Base Lakes, with particular regard to nutrient concentrations. Nutrient concentrations, trophic-state indices, and the large part of the phytoplankton biovolume composed of cyanobacteria, indicate eutrophic conditions were prevalent for Big Base …

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Impact Of Climate Variations On Soybean Yield In Eastern Arkansas: 1960-2014, J. W. Magugu, S. Feng, Q. Huang, K. Luthra Jan 2016

Impact Of Climate Variations On Soybean Yield In Eastern Arkansas: 1960-2014, J. W. Magugu, S. Feng, Q. Huang, K. Luthra

Journal of the Arkansas Academy of Science

Climate is the major factor affecting crop production; therefore, various agro-meteorological indicators have been frequently used to evaluate the impact of climate on crop production. In this study, we examined the temporal variations of agrometeorological indicators (growing degree days, total precipitation, dry spells and drought indices) during 1960-2014 and their impact on soybean yields in East Arkansas. Results show an increasing trend in growing degree days (GDDs) and dry spells, though the total precipitation during the soybean growing season remained nearly unchanged during the study period. Generally, GDDs and dry spells show a strong correlation with yields. We also evaluated …

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Impacts Of Man-Made Structures On Avian Community Metrics In 4 State Parks In Northwestern Arkansas, R. D. Keith, B. Grooms, R. E. Urbanek Jan 2016

Impacts Of Man-Made Structures On Avian Community Metrics In 4 State Parks In Northwestern Arkansas, R. D. Keith, B. Grooms, R. E. Urbanek

Journal of the Arkansas Academy of Science

Avian community metrics often differ between areas with no human disturbance and areas with high levels of human disturbance. However, the relationships between avian community metrics and smaller-scale disturbances are not as clear. Our goal was to investigate if avian abundance, richness, evenness, and diversity differed in areas with and without small-scale human developments. We used fixed-radius 50-m avian point counts to compare points which contained a man-made structure (n = 47), such as a picnic area, road, or campsite to those that did not contain a man-made structure (n = 181) at 4 state parks in Arkansas during 18 …

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