Physical Sciences and Mathematics Commons^™

Cost-Benefit Analysis Of Farmer Training In Ghanaian Cocoa Farming, Michael Norton

Agricultural Economics and Agribusiness Undergraduate Honors Theses

While billions of dollars flow into low-income countries each year to help alleviate poverty, assessing the effectiveness of these dollars is a challenging task. The literature is rich in studies that measure the benefits of rural development programs. However, many of these studies lack a temporal dimension because they measure cost and benefits for only capital investments and for only a single, static year, while not accounting for skill enhancement. By only measuring net producer benefits during the life of the development program, the cost-benefit analyses (CBA) may not truly capture the full net benefits of a given program. In …

Classification Of Satellite Time Series-Derived Land Surface Phenology Focused On The Northern Fertile Crescent, Brian Embree Bunker

Graduate Theses and Dissertations

Land surface phenology describes events in a seasonal vegetation cycle and can be used in a variety of applications from predicting onset of future drought conditions, to revealing potential limits of historical dry farming, to guiding more accurate dating of archeological sites. Traditional methods of monitoring vegetation phenology use data collected in situ. However, vegetation health indices derived from satellite remote sensor data, such as the normalized difference vegetation index (NDVI), have been used as proxy for vegetation phenology due to their repeated acquisition and broad area coverage. Land surface phenology is accessible in the NDVI satellite record when images …

Assessment Of Students’ Crisis Communications Skill Increase Based On Classroom Instruction And Second Life™ Training, Gregory C. Jernigan, Jessica R. England, Leslie D. Edgar

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Crisis communication training and skill development are critical to ensure the sustainability of the agriculture industry. The purpose of this study was to assess students’ perceptions of knowledge, ability, and skills on select crisis-related skills, tasks, and activities in order to identify the potential effectiveness of a Second LifeTM (SL) simulation. Pre- and post-test data were collected to determine the potential changes in skill in the seven crisis communication constructs of (a) related knowledge; (b) mass, group, and intrapersonal communications; (c) contingency planning; (d) use of related supplies and tools; (e) identifying learning and training needs; (f) related areas of …

Awareness, Use, And Perceptions Of Biodiesel: A Comparison Of Consumers In Belgium And The United States, Maggie Jo Pruitt, Leslie D. Edgar, Donald M. Johnson

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Belgian (N = 61) and American (N = 134) fuel consumers were interviewed in the summer of 2012 to determine their awareness, use, and perceptions of biodiesel. Consumers who were aware of biodiesel were asked their perceptions. A significantly P < 0.0001) higher percentage of Belgian consumers (78.7%) reported owning or driving a diesel vehicle compared to American consumers (9.0%). Belgian and American consumers moderately agreed biodiesel is a high-quality fuel. For both Belgian and American consumers, there was no significant association between owning a diesel vehicle and being aware of biodiesel or having purchased biodiesel. Although Belgian and American consumers agreed that using non-food crops for biodiesel is justified, Belgians were significantly less supportive than American consumers of using food crops for biodiesel. Both Belgian and American consumers disagreed with the statement “I would never use biodiesel”, and the two sets of consumers moderately disagreed that diesel engines would not run properly on biodiesel. Belgian and American consumers agreed that global warming is increasing; however, American consumers were more positive about the potential of biodiesel to reduce harmful exhaust emissions and global warming. Belgian consumers moderately agreed and American consumers agreed that biodiesel is better to use because it is made from renewable resources. Belgian and American consumers generally show similar perceptions of biodiesel, with the exception that American consumers were more positive toward the environmental and renewable aspects of biodiesel use. Recommendations for further research include gaining a better understanding of the potential positive influences that impact consumers’ perceptions of biodiesel.

Influence Of Organic Groundcovers On Mycorrhizal Colonization And Symbiosis Of Organically Managed Fruit Crops, Raven Anai Bough, Curt R. Rom

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Ground covers have the potential to impact the crop rhizosphere biology, which includes organisms such as arbuscular mycorrhizal fungi (AMF), which in turn affect the crop host plant through symbiosis. There has been evidence that a ground cover that provides a suitable environment for colonization of AMF and subsequent symbiosis could be a tool in organic fruit production. The objective of this research was to compare colonization of AMF in strawberry plant (Frageria x ananassa cv. Radiance) and apple rootstocks (Malus x domestica, cv. M. 26) grown in a greenhouse affected by various ground cover treatments. Inoculation was achieved by …

The Influence Of Poultry Litter Biochar On Early Season Cotton Growth, Taylor D. Coomer, David E. Longer, Derrick M. Oosterhuis, Dimitra A. Loka

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Cotton is known for being sensitive to cool, wet soils, especially in the early stages of growth. Amendments to soil can aid cotton seedlings in development and nutrient uptake. However, soil amendments can be costly and detrimental to the environment, and alternatives such as the addition of biochar have been considered. Biochar is produced from biomass that has gone through pyrolysis and has been shown to improve plant yield, microbial response, soil structure, soil cation–exchange capacity, and water use efficiency. This study was conducted to evaluate the effect of biochar on early season cotton growth. The aim of this study …

Short-Term Denitrification In The Metalimnion Of A Eutrophic Reservoir, Aki Kogo, Erin M. Grantz, Thad Scott

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Denitrification in metalimnetic water was examined under different conditions to determine how addition of nitrate (NO3 -) and particulate carbon (PC), aeration, and concentrations of nitrate affect denitrification. In the first experiment, water samples from a metalimnion were treated with different combinations of NO3 - and PC. Changes in excess N2 -N concentration for 10 days were measured using membrane inlet mass spectrometry (MIMS). The second experiment used the same treatments as the first experiment after aeration of water. Besides excess N2 -N concentrations, O2 concentrations were measured for 16 days. The third experiment examined how different initial concentrations of …

Evaluation Of Cover Crops In High Tunnel Vegetable Rotation, Tyler A. Patrick, Neal Mays, Jason Mcafee, Curt R. Rom

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Organic vegetable production within high tunnels allows for an extended growing season, crop protection, and environmental control. The USDA National Organic Program (NOP) standards mandate evidence that the soil has been maintained and improved over the course of production. Previous studies have indicated the potential of cover crops for reducing competitive vegetation, and improving soil quality, thus resulting in greater plant growth, nutrient uptake, and yield. However, there has been limited work in the confines of high tunnels as part of a tunnel-system rotation. Ten nitrogen-fixing and ten non-legume cover crops were established under a high tunnel and evaluated for …

Wave Profile For Current Bearing Antiforce Waves, H. Morris, W. Childs, P. Pinkston, M. Hemmati, J. Christensen

Journal of the Arkansas Academy of Science

For fluid dynamical analysis of breakdown waves, we employ a one-dimensional, three-component (electrons, ions and neutral particles) fluid model to describe a steady-state, ionizing wave propagating counter to strong electric fields. The electron gas temperature and therefore the electron fluid pressure is assumed to be large enough to sustain the wave motion down the discharge tube. Such waves are referred to as antiforce waves. The complete set of equations describing such waves consists of the equations of conservation of mass, momentum and energy coupled with Poisson’s equation. Inclusion of current behind the wave front alters the set of electron fluid …

Relationship Between Land-Use And Water Quality In Spring-Fed Streams Of The Ozark National Forest, A. Smartt, S. Ganguly, M. A. Evans-White, B. E. Haggard

Journal of the Arkansas Academy of Science

Spring-fed streams are abundant in karst topographic regions such as the Ozarks, providing an important and valuable water resource. Many of these spring-fed streams presently receive agriculture runoff, but few studies have examined the impacts of this runoff on water quality. We examined water quality in Ozark spring-fed streams surrounded by either agricultural (N=3) or primarily forested land (N=3) in the riparian zone. We hypothesized that agricultural sites would have greater dissolved nutrient concentrations and conductivity than forested sites and that water quality would fluctuate with distance from the spring source. Conductivity (p

Microwave Assisted Synthesis Of Chloropentahaptocyclopentadienediphenylphosphinoethaneruthenium(Ii), S. Muthyala, Mark Draganjac

Journal of the Arkansas Academy of Science

No abstract provided.

Distribution Of Soil Density At A Bottomland Hardwood Forest Wetland Restoration, Chicot County, Arkansas, B. E. Sleeper, Robert L. Ficklin

Journal of the Arkansas Academy of Science

Bottomland hardwood forest (BLHF) soils provide a myriad of ecosystem services, yet much information is lacking with respect to how soil physical properties influence biogeochemical cycling along topographic gradients. Current patterns of vegetation at a 149ha wetland restoration site in Chicot County, Arkansas, suggest the presence of ecologically significant variation in soil properties within the Perry Clay soil series. A study was initiated in the Lower Mississippi Alluvial Valley (LMAV) to map soil bulk density and texture as well as to identify the interrelationships between soil physical properties, soil organic carbon, and total nitrogen. A random grid was used to …

Molecular Structure Of Pentahaptocyclopentadienebis (Tetrahydrothiophene) Triphenylphosphineruthenium(Ii) Triflate, Paul M. Nave, Mark Draganjac, A. W. Cordes

Journal of the Arkansas Academy of Science

No abstract provided.

Dark Energy Interaction Models, H. Shojaei, D. Waters

Journal of the Arkansas Academy of Science

A specific interaction between dark energy and matter has been introduced in order to present possible solutions to the cosmic coincidence problem. We also compared the result of our differential equations with the experimental supernova data obtained by WMAP.

Accuracy Assessment Of The 2006 National Land Cover Database Percent Impervious Dataset, D. E. Long Ii, J. D. Carr, Hal O. Liechty, Chris Stuhlinger

Journal of the Arkansas Academy of Science

An impervious surface is any surface that prevents water from infiltrating the ground. As impervious surface area increases within watersheds, stream networks and water quality are negatively impacted. The Multi-Resolution Land Characteristic Consortium developed a percent impervious dataset using Landsat imagery as part of the 2006 National Land Cover Database. This percent impervious dataset estimates imperviousness for each 30-meter cell in the land cover database. The percent impervious dataset permits study of impervious surfaces, can be used to identify impacted or critical areas, and allows for development of impact mitigation plans; however, the accuracy of this dataset is unknown. To …

Water Quality Assessment Of Sager Creek Utilizing Physiochemical Parameters And A Family-Level Biotic Index, T. S. Wakefield

Journal of the Arkansas Academy of Science

An annual rapid bioassessment and physiochemical survey of Sager Creek in Northwest Arkansas was conducted. Sager Creek is a first to second order stream that flows through the city of Siloam Springs, AR. Invertebrate collections and water samples were collected at three different reaches, with the most downstream reach being below the effluent of the Siloam Springs Wastewater Treatment Plant. Benthic arthropods were collected, identified, and counted to produce a family-level biotic index and a family-level index of diversity. Statistical analysis revealed that these indices were significantly different for the effluent- influenced reach. However, this difference could not be correlated …

Morphometric Analysis Of Dinosaur Tracks From Southwest Arkansas, R. Shell, Stephen K. Boss

Journal of the Arkansas Academy of Science

Dinosaur trackways were discovered in Cretaceous De Queen Limestone strata in Howard County, Arkansas, in June 2011. Multiple trackways with variably sized tridactyl tracks were exposed in a commercial quarry, suggesting multiple theropod species or adult and juvenile tracks of a single species. Results of morphometric analyses of 32 plaster casts from selected trackways are reported in an effort to identify the specific track-making dinosaurs and differentiate large and small tracks. Track measurements included length and width of each track, the lengths and widths of each digit impression, and the angular spread (divarication) between digit impressions. Twenty-nine plaster casts were …

Consumers And Sustainability At Walmart: A Student's Perspective, Kealy Carter, Satish Jayachandran

Wal-Mart Sustainability Case Project

To further encourage students to analyze initial goals in comparison with outcomes over time, we have developed a consumer-oriented case—“Consumers and Sustainability at Walmart: A Student’s Perspective”—that moves beyond the perspective of internal Walmart participants to explores issues of sustainability from the point of view of a typical Walmart shopper. In this case, we examine the experience of a fictional student shopper who goes to Walmart and wants to buy sustainable products, which helps raise questions for students about what Walmart’s actions mean to them as consumers, citizens as well as business professionals. The case also asks students to evaluate …

Walmart's Sustainability Journey: Peter Redmond And The Search For Sustainable Seafood, David G. Hyatt

Wal-Mart Sustainability Case Project

In “Peter Redmond and the Search for Sustainable Seafood,” students examine the responses of Peter Redmond, Vice President and Divisional Merchandise Manager of Deli and Seafood, to organizational pressures to make seafood more sustainable at Walmart.

Walmart's Sustainability Journey: Andy Ruben And The Design Of Organizational Structures And Systems (B), David G. Hyatt, Andrew Spicer

Wal-Mart Sustainability Case Project

The case “Andy Ruben and the Design of Strategic Goals and Processes” flows from the previous discussion, by moving from the development of an ambitious vision to the challenges of adopting strategic policies and processes to reach those aspirations in practice. This case puts students into the role of Andy Ruben, Walmart’s first Vice-President for Sustainability , asking them to make concrete decisions about what should be done, in what order, and by what process if they were to implement an ambitious corporate sustainability strategy. In the case, Ruben confronts specific choices about how to define the responsibilities of the …

Walmart's Sustainability Journey: Defining Sustainable Products (A), David G. Hyatt, Andrew Spicer

Wal-Mart Sustainability Case Project

In “Defining Sustainable Products (A),” we examine Walmart’s search for a systemic solution to define a sustainable product precisely. In this case, Matt Kistler, who succeeded Andy Ruben as the company sustainability leader in 2007, knows that the company is lagging behind on its espoused goal of selling sustainable products. The case asks students step into Kistler’s shoes as he leads Walmart’s sustainability office through a systematic review of the different models and frameworks available for measuring the sustainability of products presently in use. Eventually, the students face a decision about what Walmart should do to make systemic progress with …

Walmart's Sustainability Journey: Andy Ruben And The Design Of Organizaional Structures And Systems (A), Andrew Spicer, Laura Lambdin

Wal-Mart Sustainability Case Project

The case “Andy Ruben and the Design of Strategic Goals and Processes” flows from the previous discussion, by moving from the development of an ambitious vision to the challenges of adopting strategic policies and processes to reach those aspirations in practice. This case puts students into the role of Andy Ruben, Walmart’s first Vice-President for Sustainability , asking them to make concrete decisions about what should be done, in what order, and by what process if they were to implement an ambitious corporate sustainability strategy. In the case, Ruben confronts specific choices about how to define the responsibilities of the …

Walmart's Sustainability Journey: Lee Scott's Founding Vision, Andrew Spicer, Laura Lambdin

Wal-Mart Sustainability Case Project

The first case—“Lee Scott’s Founding Vision”—takes the perspective from the apex of the organization as Walmart’s CEO, Lee Scott, develops and articulates his vision of what Walmart hopes to achieve by pursuing an aggressive sustainability strategy. This case explores the pressures that led Scott to announce the company’s ambitious sustainability goals: achieving zero waste, 100% renewable energy, and selling sustainable products. It also explores the choices made when defining and communicating the scope of the strategy, particularly through an in-depth analysis of his announcement of Walmart’s new goals in his October 2005, “Twenty-First Century Leadership” speech.

Walmart's Sustainability Journey: Defining Sustainable Products (B), David G. Hyatt, Andrew Spicer

Wal-Mart Sustainability Case Project

In “Defining Sustainable Products (A),” we examine Walmart’s search for a systemic solution to define a sustainable product precisely. In this case, Matt Kistler, who succeeded Andy Ruben as the company sustainability leader in 2007, knows that the company is lagging behind on its espoused goal of selling sustainable products. The case asks students step into Kistler’s shoes as he leads Walmart’s sustainability office through a systematic review of the different models and frameworks available for measuring the sustainability of products presently in use. Eventually, the students face a decision about what Walmart should do to make systemic progress with …

Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher

Graduate Theses and Dissertations

Rice (Oryza sativa L.)-based cropping systems are different from other row crops due to the flood-irrigation scheme used from about one month after planting to a few weeks prior to harvest. The frequent cycling between anaerobic (i.e., flooding during the growing season) and aerobic (i.e., generally, the remainder of the year) conditions can influence the rate of soil organic matter (SOM) decomposition, which can greatly influence carbon (C) and nitrogen (N) storage and sequestration in the soil over time. Therefore, a study was conducted on a silt-loam soil (fine, smectitic, thermic, Typic Albaqualf) at the Rice Research and Extension Center …

Evaluation Of The Effects Of Absorption Field Product Architecture Type On Effluent Dispersal And Soil Chemical Properties In A Profile-Limited Soil, Nina J.M. Prater

Graduate Theses and Dissertations

On-site wastewater treatment systems (OWTSs) are commonly used by households in areas of low population density to treat household wastewater and recycle it back to the environment. The traditional absorption field product used in OWTSs is a pipe-and-gravel architecture type, which has been used for decades and is the basis for most design regulations. However, new products of differing architecture types including chambers, polystyrene-aggregate, pipe-and-tire-chip, and gravel-less-pipe systems have recently become available. A three-year field study was conducted in Bethel Heights, AR to assess the performance of several newer products and to compare different architecture types to the traditional pipe-and-gravel …

Exploring The Surface Liquid And Lake Regions Of Titan With Laboratory Experimentation And Cassini Spacecraft Data, Felix Casimir Wasiak

Graduate Theses and Dissertations

The surface liquids and lake regions of Titan are studied utilizing three unique techniques, the results of which are reported in this dissertation. The development of a facility to simulate the surface conditions of Titan, and to conduct experiments on samples within that facility, brings an understanding of Titan's surface not possible through observation and modeling alone. The properties of this facility are presented, including conceptual methodology, design, implementation, performance, and experimental results. The facility, the main component of which is a simulation chamber, allows for Titan temperatures of 90 - 94 K and a 1.5 bar N2 atmosphere. The …

Penetration Forces For Subsurface Regolith Probes, Ahmed Elshafie

Graduate Theses and Dissertations

Investigating planetary bodies using penetrometers can provide detailed information about its history and evolution. An estimation of subsurface density and porosity can be made from the shape of the penetration curve. Using penetrometers mounted on planetary platforms could be challenging due to the uncertainty of the subsurface composition and since the maximum allowed force for penetration is the weight of the lander or rover on the surface. Estimation of penetration forces can provide a reliable constraint on the maximum reachable depth without endangering the whole mission. Therefore, knowledge of the required penetration force to specific depths can be helpful in …

Plasmonic And Photonic Designs For Light Trapping In Thin Film Solar Cells, Liming Ji

Graduate Theses and Dissertations

Thin film solar cells are promising to realize cheap solar energy. Compared to conventional wafer cells, they can reduce the use of semiconductor material by 90%. The efficiency of thin film solar cells, however, is limited due to insufficient light absorption. Sufficient light absorption at the bandgap of semiconductor requires a light path more than 10x the thickness of the semiconductor. Advanced designs for light trapping are necessary for solar cells to absorb sufficient light within a limited volume of semiconductor. The goal is to convert the incident light into a trapped mode in the semiconductor layer.

In this dissertation, …

Prehistoric Human Ecodynamics In The Rub Al-Khali Desert: Results Of Remote Sensing And Excavations In Dubai, United Arab Emirates, Jason T. Herrmann

Graduate Theses and Dissertations

Archaeological investigations in the Emirate of Dubai, UAE conducted by the Dubai Department of Archaeology and the University of Arkansas demonstrate that the desert inland of the Oman Peninsula was occupied not only during the Arabian Neolithic (8000-4400 BC), when the region experienced a moist period referred to as the Holocene Climatic Optimum (HCO), but also during the more arid millennia following the decline of the HCO into the Christian Era. During this period, desert settlement clustered near a band of oases, in contrast to the more widespread spatial distribution of remains of nomadic pastoralists from the Neolithic. Excavations at …