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4r Nitrogen And Water Optimization Combinations For Intermountain West Field Crops, Tina Sullivan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The concept of 4R (right source, rate, placement, and timing) management needs little introduction due to the surplus of nutrient studies in the literature for most cultivated crops. However, few studies have looked at these practices in the Intermountain West with nitrogen use, and fewer looked at 4R irrigation management. A survey was conducted to explore the interactions of nitrogen and irrigation management, test sensitivity to supply and price changes of nitrogen and irrigation for Utah and Idaho growers of small grains, corn, and potatoes, and determine the current adoption of precision agriculture options and identify the opportunities to improve. …

Tuning Hyperparameters In Supervised Learning Models And Applications Of Statistical Learning In Genome-Wide Association Studies With Emphasis On Heritability, Jill F. Lundell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Machine learning is a buzz word that has inundated popular culture in the last few years. This is a term for a computer method that can automatically learn and improve from data instead of being explicitly programmed at every step. Investigations regarding the best way to create and use these methods are prevalent in research. Machine learning models can be difficult to create because models need to be tuned. This dissertation explores the characteristics of tuning three popular machine learning models and finds a way to automatically select a set of tuning parameters. This information was used to create an …

Gene-Environment Interaction: Brain-Derived Neurotrophic Factor (Bdnf) As A Moderating Factor For The Effects Of Exercise And Diet On Cognitive And Mental Health: The Cache County Study On Memory In Aging, Chelsea L. Sanders

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Cache County Study on Memory in Aging, funded by the National Institute on Aging, studied longitudinal changes in memory and aging over 12 years’ follow-up in a population-based sample of 5,092 older adults in semirural Cache County, UT. Among the extensive interview procedures, researchers collected information regarding the participants’ demographics, health, genetic factors, diet, physical activity, and cognitive abilities. This study has allowed researchers to investigate how genetic and modifiable lifestyle factors interact to predict health, cognitive function, and psychological wellbeing in older adults.

Diet and exercise are important lifestyle factors in maintaining cognitive health and psychological wellbeing throughout …

Genetic And Environmental Interactions On Schizophrenia-Like Phenotypes In Chl1 Deficient Mice, J. Daniel Obray

Undergraduate Honors Capstone Projects

Schizophrenia is a debilitating disorder which is often characterized by dysregulation of the processing of sensory information. Schizophrenia has been shown to have a strong genetic component, as well as a strong environmental component. As such, a number of hypotheses such as the diathesis stress hypothesis have been developed to explain the etiology of schizophrenia. As most of these theories attempt to account for a genetic and an environmental factor, they are often viewed as double-hit models of schizophrenia. Several theories have emerged as potential explanations for the symptoms of schizophrenia. The dopamine hypothesis suggests that the basal level of …

Synthesizing Research And Education: Ecology And Genetics Of Independent Fern Gametophytes And Teaching Science Inquiry And Content Through Simulations, Aaron M. Duffy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The mission statements of Utah State University and the Department of Biology, as well as the requirements of funding agencies like the National Science Foundation encourage an integration of teaching and research. I have attempted to achieve that in my dissertation work by using tools I originally created to support and inform my biological research projects to teach science content and inquiry to middle school and undergraduate students.

Chapter 2 of this dissertation reports the results of surveys for Hymenophyllum wrightii, a fern with independent gametophyte populations in the Pacific Northwest, which improved our understanding of the range, distribution, …

The Ecology And Genetics Of Schoenoplectus Maritimus, An Important Emergent Macrophyte, Across Diverse Hydrologic Conditions—Implications For Restoration, Amanda Clare Sweetman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wetlands in the Intermountain West are typically dominated by large monotypic stands of emergent wetland plants, are highly productive, and support millions of migratory birds as important stops along the Pacific Flyway. In systems with low species diversity, such as these, diversity within a species (intraspecific diversity) can play an important role in population fitness and ecosystem functioning and can impact restoration success. Our research was designed to inform future restoration and management activities by studying the pattern of diversity within and among natural plant populations, and by studying how hydrology and plant materials used in restoration (source and diversity …

Apoptotic And Epigenetic Induction Of Embryo Failure Following Somatic Cell Nuclear Transfer, Aaron Patrick Davis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The cloning of domestic species has tremendous potential, as the technology can be used in selective breeding, conservation, and the production of transgenic animals. The technique of cloning involves the transplant of DNA from a cell to a recipient gamete. Following transfer to a surrogate, the cloned embryo may successfully complete development to a live offspring. Despite intensive research, the success rate of cloning remains prohibitively low, and the potential benefits of cloning have not yet been realized. Embryos produced from cloning suffer from high rates of embryo degradation, implantation failure, and abortion. The goal of this dissertation research project …

The Status Of Dwarfed Populations Of Short-Horned Lizards (Phrynosoma Hernandesi) And Great Plains Toads (Anaxyrus Cognatus) In The San Luis Valley, Colorado, Megan E. Lahti

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The San Luis Valley is a large valley formation in Colorado surrounded on either side by mountain ranges exceeding 4,267 m. Within the Valley, two of the 14 amphibian and reptile species are dwarfed: the short-horned lizard (Phrynosoma hernandesi) and the Great Plains toad (Anaxyrus cognatus). Since its initial reporting in 1968 and confirmation in 1981, no research further investigating this dwarfism has been conducted. I collected morphological measurements to determine the extent and patterns of dwarfism of both species. I then investigated the genetics of both species using mitochondrial DNA to determine whether they are …

Identification Of Key Genes Required For Abiotic Stress Response In Arabidopsis Thaliana, Saori Endo

Undergraduate Honors Capstone Projects

To identify key genes that are required for stress response, a reverse genetics approach was taken to manipulate expression of candidate genes in plants. In this project, two potential regulatory genes which were originally identified as stress-responsive genes from a microarray experiment in Arabidopsis were examined for their roles in stress tolerance. Over-expression of gene A, which was up-regulated under stress conditions based on the array data, caused earlier flowering and improved plant growth under salinity and dehydration stress conditions at the seedling stage. Over-expression of gene B, which was down-regulated under stress conditions based on the array data, resulted …

Single Nucleotide Polymorphism (Snp) Analysis Of Tumor Necrosis Factor (Tnf)-Α In Pediatric Autoimmune Neuropsychiatric Disorders Associated With Streptococcal Infections (Pandas) Subjects, Corinna Wilhelmina Vonniederhausern

Undergraduate Honors Capstone Projects

In an ongoing research project, the Center for Persons with Disabilities at Utah State University, in collaboration with Dr. Susan E. Swedo at the National Institute of Mental Health, is evaluating genetic factors affecting the development of PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections). PANDAS is manifested in a group of prepubertal children who develop obsessive-compulsive disorder (OCD) following infection with Group A beta-hemolytic Streptococcal (GABHS) bacteria. We are assessing single nucleotide polymorphisms (SNPs) in the promoter region of tumor necrosis factor (TNF)-α and other cytokines known to be important in autoimmune diseases.

Obesity: Environment Vs. Genetics, Kammi Marie Reeder Hansen

Undergraduate Honors Capstone Projects

The prevalence of overweight and obese individuals is rising. Between 1980 and 1990 there was an 8% increase in the prevalence of obesity. Obesity is associated with many diseases such as hypertension, type 2 diabetes, heart disease and cancer. Over $39 billion dollars is spent annually on the illnesses associated with obesity. Our American culture has been blamed for the rise in obesity, yet there are obviously many people living in the American culture that are not obese. Researchers have turned to genetics to explain this phenomenon. This article will examine the many environmental factors that contribute to obesity and …

Evolutionary Genetics Of Canyon Treefrogs (Hyla Arenicolor), Roy A. Murray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Population genetics is the study of the mechanisms that cause genetic change in populations over time. Genetic changes may lead to both adaptive evolution and speciation. While the former process is fairly well understood, many questions remain unanswered with regard to the process of speciation. How important is population isolation in the process of speciation? How long must populations be isolated before speciation is complete? Are the genetic changes that take place during speciation caused mainly by natural selection or does genetic drift play a substantial role? Can genetic drift alone lead to reproductive isolation? These types of questions have …

Genetics And Applications Of Nisin Production In Lactococcus Lactis Subsp. Lactis And Conjugal Exchange Of This Trait, Jeffery R. Broadbent

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chapter I reviews current literature on gene transfer systems in lactic acid bacteria, how genetically altered microorganisms for food are presently regulated, and how nisin is used as a food preservative.

Chapter II investigates previous reports which linked genes for nisin biosynthesis and sucrose utilization (Nip⁺Suc⁺) to plasmid DNA in two well characterized L. lactis subsp. lactis strains. Plasmid curing studies, conjugations, and DNA-DNA hybridizations indicated that these genes were encoded by chromosomal loci in all Nip⁺Suc⁺ strains examined. Similar results were noted in nisin-sucrose transconjugants of L. lactis subsp. cremoris and S. …