Life Sciences Commons^™

Ecology Of Neotropical Arboreal Snakes And Behavior Of New World Mollusk-Eating Snakes, Julie M. Ray

Biological Sciences Theses & Dissertations

The Neotropics is a biologically diverse region that provides man opportunities for ecological and behavioral studies. I utilized the speciose ophidian fauna of central Panama to explore the general ecology of arboreal snakes, the defensive behaviors of the snake community, and the diet of mollusk-eating snakes. I studied arboreal species to understand interspecilic relationships in several morphometric characters and to examine preferences in habitat. There were significant morphometric differences in relative length of jaw, mass, tail length, and size at midbody. The arboreal realm was partitioned among species by distance to ground, distance to water, and diameter of the perch. …

Analysis Of N-Linked Oligosaccharides Of Prostate-Specific Antigen And Prostatic Acid Phosphatase In Prostatic Fluids, Krista Yaudes White

Theses and Dissertations in Biomedical Sciences

Presently, prostate cancer is the most common cancer afflicting men in the United States, with serum PSA being the "gold standard" protein biomarker used in the clinic for detecting and diagnosing prostate cancer. Nonetheless, serum PSA levels can also be elevated in non-cancerous conditions as well, such as benign prostatic hyperplasia (BPH). Due to this overlap, many unnecessary biopsies and radical prostatectomies occur, leading to patient distress. Despite recent advances to clinical assays which consider other clinical parameters, there is still a great need for improved clinical detection methodologies for prostate cancer, including improved biomarkers. Therefore, this research project aims …

Computational Studies On R67 Dihydrofolate Reductase: An Investigation Into Its Unique Binding Patterns, Chuanyin Shi

Theses and Dissertations in Biomedical Sciences

R67 dihydrofolate reductase (R67 DHFR) is a plasmid encoded enzyme which catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF) using NADPH as a cofactor. R67 DHFR is a homo-tetramer and D2 symmetric. It contains only one active site, which spans the central channel of the enzyme. The active site can bind either two reactants (DHF), two cofactors (NADPH) or one of each (NADPH/DHF), which is the productive ternary complex (i.e. the complex which yields product). In order to favor formation of the productive complex, this enzyme exhibits binding cooperativity. Unlike other allosteric enzymes which achieve binding cooperativity through conformational …

Oxidative Stress, Calcium Homeostasis, And Altered Gene Expression In Human Lung Epithelial Cells Exposed To Zno Nanoparticles, Chuan-Chin Huang

Masters Theses

"The influence of 20 nm ZnO nanoparticles on oxidative stress, intracellular calcium homeostasis, and gene expression was studied in human bronchial epithelial cells (BEAS-2B). ZnO caused a concentration- and time-dependent cytotoxicity while elevating oxidative stress and causing membrane damage (cellular LDH release). There was a remarkably steep relationship between concentration and toxicity at concentrations from 5 to 10 μg/ml. Exposure to ZnO increased intracellular calcium levels in a concentration- and time-dependent manner. Treatment with the antioxidant N-acetylcysteine prevented cell loss and diminished the increase in intracellular calcium concentration, suggesting oxidative stress mediated cytotoxicity. Exposure to a sublethal concentration of ZnO …

Transitions And Tipping Points In Complex Environmental Systems, Nsf Advisory Committee For Environmental Research And Education

Long Term Ecological Research Network

No abstract provided.

Advances And Applications Of Dezert-Smarandache Theory (Dsmt) For Information Fusion (Collected Works), Vol. 3, Florentin Smarandache, Jean Dezert

Branch Mathematics and Statistics Faculty and Staff Publications

This volume has about 760 pages, split into 25 chapters, from 41 contributors. First part of this book presents advances of Dezert-Smarandache Theory (DSmT) which is becoming one of the most comprehensive and flexible fusion theory based on belief functions. It can work in all fusion spaces: power set, hyper-power set, and super-power set, and has various fusion and conditioning rules that can be applied depending on each application. Some new generalized rules are introduced in this volume with codes for implementing some of them. For the qualitative fusion, the DSm Field and Linear Algebra of Refined Labels (FLARL) is …

Limits To Maize Productivity In The Western Corn-Belt: A Simulation Analysis For Fully Irrigated And Rainfed Conditions, Patricio Grassini, Haishun Yang, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Unlike the Central and Eastern U.S. Corn-Belt where maize is grown almost entirely under rainfed conditions, maize in the Western Corn-Belt is produced under both irrigated (3.2 million ha) and rainfed (4.1 million ha) conditions. Simulation modeling, regression, and boundary-function analysis were used to assess constraints to maize productivity in the Western Corn-Belt. Aboveground biomass, grain yield, and water balance were simulated for fully irrigated and rainfed crops, using 20-year weather records from 18 locations in combination with actual soil, planting date, plant population, and hybrid-maturity data. Mean values of meteorological variables were estimated for three growth periods (pre- and …

A Nonsense Mutation In A Cinnamyl Alcohol Dehydrogenase Gene Is Responsible For The Sorghum Brown Midrib6 Phenotype1[W][Oa], Scott E. Sattler, Aaron J. Saathoff, Eric J. Haas, Nathan A. Palmer, Deanna L. Funnell, Gautam Sarath, Jeffrey F. Pedersen

Department of Agronomy and Horticulture: Faculty Publications

Recently, bmr6 plants were shown to have limited cinnamyl alcohol dehydrogenase activity (CAD; EC 1.1.1.195), the enzyme that catalyzes the conversion of hydroxycinnamoyl aldehydes (monolignals) to monolignols. A candidate gene approach was taken to identify Bmr6. Two CAD genes (Sb02g024190 and Sb04g005950) were identified in the sorghum genome based on similarity to known CAD genes and through DNA sequencing a nonsense mutation was discovered in Sb04g005950 that results in a truncated protein lacking the NADPH-binding and C-terminal catalytic domains. Immunoblotting confirmed that the Bmr6 protein was absent in protein extracts from bmr6 plants. Phylogenetic analysis indicated that Bmr6 is …

High-Yielding Corn Response To Applied Phosphorus, Potassium, And Sulfur In Nebraska, Charles S. Wortmann, Achim R. Dobermann, Richard B. Ferguson, Gary W. Hergert, Charles A. Shapiro, D. D. Tarkalson, Daniel T. Walters

Department of Agronomy and Horticulture: Faculty Publications

Nutrient management recommendations may change as yield levels and efficiency of crop production increase. Recommendations for P, K, and S were evaluated using results from 34 irrigated corn (Zea mays L.) trials conducted in diverse situations across Nebraska. The mean yield was 14.7 Mg ha^-1 with adequate fertilizer applied. Th e median harvest index values were 0.52, 0.89, 0.15, and 0.56 for biomass, P, K, and S, respectively. Median grain yields were 372, 49, and 613 kg kg^-1 of above-ground plant uptake of P, K, and S, respectively. The estimated critical Bray-1 P level for corn response …

Farming Systems Education: Case Study Of Swedish Test Pilots, Lennart Salomonsson, Anna Nilsson, Sofia Palmer, Adam Roigart, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

We describe and analyze a pedagogical experiment that introduced a broad and holistic perspective on complete farming systems, systemic learning tools, and a participatory learning strategy at an early stage in agronomy education. The paper describes the adventure of three students, who came from a conventional agronomy program at the Swedish University of Agricultural Sciences (SLU), who were frustrated with the lack of integrated approaches to the study of agricultural systems and a strong focus on molecular-level processes in their first year of education. They encountered a narrow focus in most courses and the overall curricula of agricultural education that …

Alternative Methods For Wetland Restoration In The Rainwater Basin, Nebraska, Usa, Nancy Nicolai, James L. Stubbendieck

Department of Agronomy and Horticulture: Faculty Publications

South-central Nebraska is recognized as a focal point of the mid-continent migratory waterfowl flyway. Substantial wetland alterations led to a critical need for restoration. Managers have restored wetlands by scraping with heavy earthmoving equipment to remove excess organic material and near-monocultures of reed canarygrass (Phalaris arundinacea L.) but managers report high costs and topsoil perturbation. Moderate livestock grazing was tested to compare results with those achieved with mechanical techniques. Advantages of grazing could include low costs and less soil perturbation. During the 2006 and 2007 growing seasons, we compared cover of bare ground and open water and plant species …

Research Emphasis – Forage And Bioenergy Crop Management, John A. Guretzky

Department of Agronomy and Horticulture: Faculty Publications

Guretzky specializes in research on forage and bioenergy crop management that will assist agricultural producers and landowners in meeting their goals. The first area of research involves Drs. Jon Biermacher and Billy Cook for the evaluation of management practices of switchgrass in forage and bioenergy systems. Objectives include: 1.) assessing potential on-farm biomass yields and production economics of switchgrass; 2.) documenting effects of location, harvest system and nitrogen fertilizer rates on biomass yields, forage quality, stand persistence and nutrient removal rates; 3.) evaluating establishment and biomass production responses to phosphorus and potassium fertilization; 4.) determining how stocker cattle gains on …

Blue Fescue Overseeding Improves Performance Of Fairway Height Buffalograsses, Bekele G. Abeyo, Robert C. Shearman, Roch E. Gaussoin, Leonard A. Wit, Desalegn D. Serba, Ugur Bilgili

Department of Agronomy and Horticulture: Faculty Publications

Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] use as a fairway turfgrass is limited in northern portions of its adaptation zone by its extended winter dormancy and tan coloration in early spring and late fall. Cool-season grasses mixed with buffalograss could enhance turfgrass appearance and performance in fall and early spring. Research was conducted near Mead, NE, with eight buffalograss genotypes maintained under fairway conditions to determine the effect of blue fescue (Festuca ovina L. var. glauca Lam.) overseeding rate on turfgrass performance. Interactions were nonsignificant in most cases so main effects are emphasized. Differences were observed between seeding rates and …

Gibberellic Acid Promotes Seed Germination In Penstemon Digitalis Cv. Husker Red, Anderson Machado De Mello, Nereu Augusto Streck, Erin E. Blankenship, Ellen Paparozzi

Department of Agronomy and Horticulture: Faculty Publications

Penstemon seed often shows an inconsistent or a low germination percentage. Although most select cultivars are propagated by cuttings, for export to other countries, seed is preferred. Three experiments were conducted to determine if soaking seed in gibberellic acid (GA₃) would increase seed germination of Penstemon digitalis cv. Husker Red. GA₃ concentrations used were 0, 10, 50, 100, 200, and 500 mg∙L^–1 (first experiment); 0, 500, 1000, and 1500 mg∙L^–1 (second experiment); and 0, 500, and 1000 mg∙L^–1 (third experiment). The first and second experiments were conducted in a growth chamber, whereas the third …

Antibiotic Use In Animal Production: Environmental Concerns, Teshome H. Regassa, Richard K. Koelsch, Charles S. Wortmann, Richard F. Randle, Akwasi A. Abunyewa

Department of Agronomy and Horticulture: Faculty Publications

Introduction

Antibiotic1 use in animal production has led to improved feed use efficiency and increased growth rates. In turn, these resulted in reduced food production costs and reduced excrement of manure nutrients which may cause pollution problems.

On the other hand, antibiotic use leads to antibiotic resistance and a possible reduction in effectiveness of treatment options for both animals and humans. This publication addresses these issues.

Disease-causing microorganisms2, including bacteria,are the most diverse and numerous organisms on earth. Diverse in their habitat, environmental adaptation, and mechanisms of reproduction, they have short generations with high multiplication rates. Such characteristics help develop …