Digital Commons Network^™

Characterization Of Maize Genes In Response To Aspergillus Flavus Infection And Aflatoxin Accumulation, Matthew Constantine Asters

Theses and Dissertations

Aspergillus flavus is a pathogenic fungus causing maize ear rot disease and producing aflatoxins that are carcinogenic to humans and animals. Characterizing maize host resistance mechanisms and prioritizing candidate resistance genes are important to the development of resistant maize germplasm. This study investigated transcriptomics approaches and statistics methods on the identification of maize host resistance genes. Full-length cDNA libraries were also constructed and evaluated for gene cloning and functional analysis. This study established important sources for functional studies on differentially expressed genes and for identification of allelic gene forms to characterize gene polymorphisms and facilitate the development of DNA markers.

Characterization Of Sediment Microbial Communities And Analysis Of Biogeochemical Responses To Eutrophication In Southeastern Estuaries, Gary Alon Blakeney

Theses and Dissertations

Estuaries are valuable economic resources to humans. However, changes in these ecosystems, such as alteration in nutrient availability, can impose eutrophic pressures. Traditionally, estuaries have been monitored through chemical analyses that measure factors such as sediment oxygen demand (SOD) and reduced forms of Fe(II), Mn(II), and H2S. These methods are time consuming and have been proven to be unreliable. This study was conducted to determine if using T-RFLP analysis could be used as a proxy for some of the current methods used to monitor eutrophication. Using SPSS to perform a principle component analysis, it was determined that connections can be …

Computational Methods On Study Of Differentially Expressed Proteins In Maize Proteomes Associated With Resistance To Aflatoxin Accumulation, Alka Tiwari

Theses and Dissertations

Plant breeders have focused on improving maize resistance to Aspergillus flavus infection and aflatoxin accumulation by breeding with genotypes having the desirable traits. Various maize inbred lines have been developed for the breeding of resistance. Identification of differentially expressed proteins among such maize inbred lines will facilitate the development of gene markers and expedite the breeding process. Computational biology and proteomics approaches on the investigation of differentially expressed proteins were explored in this research. The major research objectives included 1) application of computational methods in homology and comparative modeling to study 3D protein structures and identify single nucleotide polymorphisms (SNPs) …

Determination Of The Weak Charge Of The Proton Through Parity Violating Asymmetry Measurements In The Elastic Ep Scattering, Adesh Subedi

Theses and Dissertations

The Qweak experiment has taken data to make a 2.5 percent measurement of parity violating elastic ep asymmetry in the four momentum transfer region of 0.0250 (GeV/c)2. This asymmetry is proportional to the weak charge of the proton, which is related to the weak mixing angle, sin2(thetaW). The final Qweak measurement will provide the most precise measurement of the weak mixing angle below the Z° pole to test the Standard Model prediction. A description of the experimental apparatus is provided in this dissertation. The experiment was carried out using a longitudinally polarized electron beam of up to 180 microampere on …

Determining The Effect Of Auxin Herbicide Concentration And Application Timing On Soybean (Glycine Max) Growth And Yield, Alanna Blaine Scholtes

Theses and Dissertations

Auxin resistant cropping systems will provide producers with an alternative option for weed management, but with this new technology also comes the concern of off target movement of dicamba and/or 2,4-D to susceptible crops. Research was conducted over multiple site years in order to determine the effect of soybean response to different application timings and rates of 2,4-D and dicamba. 2,4-D was applied at 1X (0.56 kg ae/ha), 1/4X, 1/16X, 1/64X, and 1/256X rates, and dicamba was applied in a separate study at 1X (0.56 kg ae/ha), 1/4X, 1/16X, 1/64X, 1/256 and 1/1024X. All rates were applied at the V3 …

Evaluation Of Effectiveness, Reproducibility, And Repeatability Of Using Dentition For Estimating Cattle Age, Timothy F. Best

Theses and Dissertations

Study objectives were to determine the effectiveness, reproducibility, and repeatability of dental evaluation for estimating cattle age. Cattle (n = 400) aged 1.5 to 20 yr were evaluated by 3 technicians for estimated age via dentition. A subset (n = 383) was aged again 4 wk later by the same observers. Age estimations were most accurate in YOUNG (< 5 yr old) cattle with at least 95.7% rate of accuracy within 2 yr across all observers and observation events. For MIDDLE (6 to 10 yr old) and OLD (> 10 yr old) cattle, these accuracies were 81.5 and 62.1%, respectively. Reproducibility proved high, with all observers consistently assigning age estimates within 1 yr of one another for more than 9 out of 10 YOUNG animals; all observers agreed on at …

Electrical Breakdown Strength Of 5 Kv Ethylene Propylene Rubber (Epr) Cable Under Ac Voltage, Bishal Pradhan

Theses and Dissertations

Ethylene propylene rubber (EPR) cable has been extensively used for distribution of power. The insulation of cable should withstand electrical, thermal, mechanical, and chemical stresses during its operation. It is imperative to measure the data providing dielectric strength of EPR cable for these stresses. Significant improvements on the quality of insulation have been progressing for better performance of cable under these stresses. This study deals with ac voltage stress imposed on the cable. The electrical breakdown strength of 5kV EPR cable under ac voltage has been measured by constructing a suitable test set in Mississippi State University High Voltage Lab.

Development And Optimization Of A Rapid Assay Kit For The Detection Of Vibrio Cholerae In Bivalves, Demarcus Rashad Carter

Theses and Dissertations

A rapid assay kit for Vibrio cholerae (Vc) was developed to detect and quantify Vc cells in oyster samples within 24 h. The kit, formulated within a two -phase (liquid and solid) 96-well plate, can detect biomarker expression of Vc when the enrichment broth and incubation temperature are optimized. The kit showed 91 % selectivity and 92 % specificity when tested with 23 inclusive Vc and 106 exclusive non-Vc strains. The kit was further optimized using 47 samples of oysters, clams, and soil. There was no significant difference in most probable number between the kit, conventional PCR and BAX PCR …

Development Of A Dynamic Performance Management Framework For Naval Ship Power System Using Model-Based Predictive Control, Jian Shi

Theses and Dissertations

Medium-Voltage Direct-Current (MVDC) power system has been considered as the trending technology for future All-Electric Ships (AES) to produce, convert and distribute electrical power. With the wide employment of highrequency power electronics converters and motor drives in DC system, accurate and fast assessment of system dynamic behaviors , as well as the optimization of system transient performance have become serious concerns for system-level studies, high-level control designs and power management algorithm development. The proposed technique presents a coordinated and automated approach to determine the system adjustment strategy for naval power systems to improve the transient performance and prevent potential instability …

Inspection Of Timber Bridge Longitudinal Decks With Ground Penetrating Radar, Brian K. Brashaw

Theses and Dissertations

Advanced nondestructive inspection techniques like stress wave timing and resistance microdrilling have been used to successfully inspection timber bridges, but it is most effective on girder style bridges. There is a noted need to develop additional inspection techniques for longitudinal deck/slab timber bridges, which comprise about 20% of the national bridge inventory. One technique that holds potential is ground penetrating radar, a recognized nondestructive testing technique that has been used effectively for many different environmental and transportation applications. It has been utilized successfully to identify buried objects, internal defects and material changes. The objective of this research was to assess …

Evaluation Of Herbicide Formulation And Spray Nozzle Selection On Physical Spray Drift, Jasper Lewis Cobb

Theses and Dissertations

New transgenic crops are currently being developed which will be tolerant to dicamba and 2,4-D herbicides. This technology could greatly benefit producers who are impacted by weed species that have developed resistance to other herbicides, like glyphosate-resistant Palmer Amaranth. Adoption of this new technology is likely to be rapid and widespread which will lead to an increase in the amount of dicamba and 2,4-D applied each season. It is well-documented that these herbicides are very injurious to soybeans, cotton, tomatoes, and most other broadleaf crops, and their increased use brings along increased chances of physical spray drift onto susceptible crops. …

An Observation Of Displaced Manufacturing Workers In Their Transition For Successful Reemployment Through Community College Education/Retraining Programs, Christina Granderson

Theses and Dissertations

The economic changes that have occurred in this country over the course of this past decade have had a grave impact on manufacturing workers, which has forced many of these workers to transition into new career fields. As workers are faced with having to start new career paths, the community college has served as a hub of information and a source of inspiration to begin new careers. Through programs such as the federal Trade Adjustment Assistance (TAA) program, these dislocated workers are able to acquire a new skill or trade. A qualitative study will investigate how dislocated workers make a …

Analyzing Predictors Of Bullying Victimization At School, Hatice Cecen Celik

Theses and Dissertations

Bullying victimization in school settings is a serious problem in many countries including the United States. Bullying victimization has been associated with serious incidents of school violence as well as detrimental physical, psychological, emotional, and social consequences for its victims. Given its consequences, it is crucial to understand who is more likely to be targeted for bullying victimization. This study examines whether a number of important factors such as gender, physical and interactionist school security measures, and involvement in extracurricular activities influence individuals’ risk of bullying victimization from social bond and routine activity perspectives. The study employs the 2011 School …

Study Of The Mechanisms Of Heat Tolerance In Ivy Geraniums, Mingshu Zhang

Theses and Dissertations

Ivy geranium (Pelargonium peltatum) is a heat susceptible species with its heat tolerance varying among varieties. Reactive oxygen species (ROS) and in-vivo defense systems are related to plant heat damage and heat tolerance. Application of chelated-iron has also been reported to enhance ivy geranium heat tolerance; however, the correlation of ROS, relative enzyme stability, and iron content to differences in heat tolerance in ivy geraniums is unknown. Here we show that the H2O2 content and ROS scavenging enzyme stability in ivy geranium varies with varieties and active iron is not related to heat tolerance in ivy geranium. H2O2 content in …

Summer Engineering Academies: Developing Participant Self-Efficacy In Engineering, Nathan Eric Heiselt

Theses and Dissertations

With the growing concern over the reduction of university students pursuing degrees in STEM fields, there are a number of entities sponsoring and implementing programs for young people in order to promote interest in and self-efficacy for these fields. Summer Engineering Academies (SEAs) are implemented in a variety of settings by stakeholders with a single purpose: to expose young people to the fields and work of engineers in the hope of recruiting them. This study is seeks to identify whether any positive changes to the self-efficacy of the participants occurs through the curricula of the program. This self-efficacy can be …

Intensification As A Survival Strategy For Early Settlers On The Tombigbee National Forest, Jessica L. Gisler

Theses and Dissertations

This thesis investigates the relationship between success and access to children, slaves, and kin as labor sources during the period of 1833 to 1865 in northeast Mississippi. The theoretical concepts of agricultural intensification and relative intensity were used to measure variability among the households. Artifacts from seven archaeological sites were used to establish mean dates. These sites were tied to their original occupants through historic records. A historic document search revealed the number of slaves and children each family had, and whether they had kin living nearby. Agricultural census records showed the productivity of each farm during the study period. …

Investigating Nondestructive Evaluation Of Carbon Fiber Reinforced Polymer Beams Using Embedded Terfenol-D Particle Sensors, Jonathan D. Rudd

Theses and Dissertations

Reinforced fiber polymer composites are a class of materials that are composed of multiple constituents that work together to create a material specific for applications. By combining different fibers and matricies, laminates can be created that meet demands for high specific stiffness, damping specifications, and electrical resistance. However, their internal complexity subjects them to a number of internal failure modes that have the potential to fail the laminate. Those failure mechanisms are fiber breaking, microcracking in the matrix, debonding of the fibers from matrix, and delamination of ply layers. To assess these failures, nondestructive evaluation methods have been developed to …

Investigation Of The Beneficial Effect Of Enterobacter Cloacae Strain Jd6301 On Mice Challenged With Escherichia Coli O157:H7, Jessica Grissett Wilson

Theses and Dissertations

The environment of the gastrointestinal (GI) tract is an extremely complex system made up of not only host cells, but also many beneficial microbes. Disruption of this environment can often lead to disorders and health issues. To help balance this system, probiotics have often been administered to both humans and animals, such as livestock. This study aimed to determine what beneficial effects a novel strain of Enterobacter cloacae, strain JD6301, could offer to a host in the presence of an enteric infection with E. coli O157:H7. Upon administration of JD6301, supplemented animals had overall less E. coli present in the …

On A Ductile Void Growth Model With Evolving Microstructure Model For Inelasticity, Yustianto Tjiptowidjojo

Theses and Dissertations

The objective of this work is to develop an evolution equation for the ductile growth of a spherical void in a highly strain rate and temperature dependent material. The material considered in this work is stainless steel 304L at 982 °C. The material is characterized by a physically-based internal state variable model derived within consistent kinematics and thermodynamics — Evolving Microstructure Model for Inelasticity. Through this formulation, the degradation of the elastic moduli due to damage has been naturally acquired. An elastoviscoplasticity user material subroutine has also been developed and implemented into a commercially available finite element software ABAQUS. The …

Soundscape Evaluation On Mississippi State University Campus, Yalcin Yildirim

Theses and Dissertations

The term soundscape, used for the first time at the end of 1970s, refers to the sum of the sounds that can be heard and perceived by people in a specific environment. The concept of soundscape has recently received attention in planning and design disciplines. Recent studies on soundscape have shown that the acoustic environment plays an important role for the comfort of site users. Hence, this research investigates how objective measurement of soundscape might be different from subjective perceptions of users in the Mississippi State University Campus as a public open space due to demographic and climatic variations. The …

Finite Element Analysis Of Adhesive Bonding Performances Of Wooden Dowel Pin Joints In Furniture, Xin Sun

Theses and Dissertations

This study was performed to investigate how pressure, glue amount, dowel penetration depth and wood grain orientation affect direct withdrawal resistances of dowel pin joints both experimentally and numerically, and develop FE (finite element) models to simulate tensile strength, contact pressure, and shear stress occurred in dowel pin joints. Results indicated that the direct withdrawal resistance load of a dowel pin joints can be predicted based on knowing the glue bonding shear strength between dowel and joint member materials and the pressure between the contact surfaces of the dowel and hole of a connected joint member. The FE contact element …

Growth Implant Timing And Effectiveness In Beef Cattle, Herschel Brad Jones

Theses and Dissertations

One hundred crossbred beef steers were used in two experiments to evaluate effects of growth implants on performance. Steers were implanted either at 3.5 months and weaning (CALF); at weaning (WEAN); or not implanted (NONE). In Experiment 1 implanted steers weighed more at weaning (P = 0.01), and had a higher ADG for the entire trial compared to non-implanted steers (P = 0.03). In Experiment 2, at 80 d post wean, implanted steers outweighed NONE (P = 0.09). Overall ADG (P = 0.01) was greater for cattle that were implanted. In the feedlot the CALF group had the lowest ADG …

Improved Methods For The Analysis Of Estrogen Residues In Environmental Aqueous Matrices, Sameera Ranmal Gunatilake

Theses and Dissertations

Improved analytical methods using novel cleanup techniques and inexpensive instrumentation for the determination of residue estrogens in municipal wastewater and swine lagoon wastewater have been developed. Presented approaches are less expensive, less time consuming, yet produce comparable detection limits and extraction efficiencies to existing methods. Chapter I provides an overview on environmental estrogens. Chapter II describes a novel method to quantify five estrogens including estriol, estrone, 17alpha-estradiol, 17beta-estradiol, and 17alpha-ethynylestradiol in influent and effluent municipal wastewater. The method includes sample preparation using solid-phase extraction followed by a “QuEChERS” cleanup, dansylation and LC/MS/MS detection. Hydrophilic-lipophilic balance solid phase extraction (SPE) was …

Examining The Intra-Organizational Differences Among Municipal Employees: An Empirical Investigation Of Public Safety Workers In The Municipal Workforce, Joseph J. Breen

Theses and Dissertations

Attracting, motivating, and retaining public service employees continues to challenge both state- and municipal-level managers. Beginning with Perry’s (1996) public service motivation (PSM) construct, academics and practitioners focused considerable efforts in the identification of measures and factors influencing levels of motivation with the overall intent of identifying the key components of increasing employee motivations, thereby increasing the possibility of retaining the capable employees. While this effort has focused on managerial distinctions, groupings between genders, racial backgrounds, and tenure lengths, one significant comparison has yet to be explored—the public safety worker. Identifying and examining the motivating factors of police and fire, …

2014 Fall Commencement, Harding University

Commencement Programs

Program for the Harding University Commencement on December 13.

Commencement Speaker: Rex Nelson

The Primary Source, Vol. 33, Issue 2, Elizabeth La Beaud

The Primary Source

No abstract provided.

Victims Of Success: Managing The Consequences Of Digital Outreach , Sean Benjamin

The Primary Source

No abstract provided.

Digi Days: Using The Rey Papers To Teach Digitization To Library Science And Archival Students, Emilie Aplin, Matthew Griffis

The Primary Source

No abstract provided.

Kirkland D.W., 2014 - Role Of Hydrogen Sulfide In The Formation Of Cave And Karst Phenomena In The Guadalupe Mountains And Western Delaware Basin, New Mexico And Texas, Leslie A. Melim

International Journal of Speleology

No abstract provided.

Poets Talking Shop (The Poet’S Work, Ed. Reginald Gibbons), George Woodcock

Ontario Review

GEORGE WOODCOCK is the founding editor of Canadian Literature. Among his many books are The Canadian Novel in the Twentieth Century; Gabriel Dumont: The Metis Chief and His Lost World; and Thomas Merton: Monk and Poet. He is a contributing editor of OR.