Digital Commons Network^™

Control System For Variable-Orifice Mechatronic Spray Nozzle For Regulation Of Application Rate And Droplet Size Spectra, Rodney Rohrer

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Traditional fixed-orifice spray nozzles are selected for flow rate and droplet spectra required for a given pesticide application. Although limited variation in flow can be achieved by adjusting system pressure, this can adversely affect spray quality. Other nozzle configurations, such as Pulse Width Modulated (PWM) nozzles or passive variable-orifice designs, are intended to maintain consistent droplet size and spray pattern as flow rate is changed but those too have limitations.

A variable-orifice nozzle modified by Luck (2012) can span multiple droplet spectra and offers independent control of flow and droplet size; however, an advanced control system must be developed to …

Arbor Day Foundation Tree Program Recommendation, Kyler Caverzagie

Honors Program: Senior Projects (Public)

We propose including an addition to the Tree City application for a grant awarded to Tree Cities that plant trees in underserved areas of the community.

We also recommend inviting Tree Campus to join the Alliance for Community Trees (ACT). Through membership, they will attend and participate in the Partners in Community Forestry Conference.

Emerging Approaches To Measure Photosynthesis From The Leaf To The Ecosystem, Matthew H. Siebers, Nuria Gomez-Casanovas, Peng Fu, Katherine Meacham-Hensold, Caitlin E. Moore, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Measuring photosynthesis is critical for quantifying and modeling leaf to regional scale productivity of managed and natural ecosystems. This review explores existing and novel advances in photosynthesis measurements that are certain to provide innovative directions in plant science research. First, we address gas exchange approaches from leaf to ecosystem scales. Leaf level gas exchange is a mature method but recent improvements to the user interface and environmental controls of commercial systems have resulted in faster and higher quality data collection. Canopy chamber and micrometeorological methods have also become more standardized tools and have an advanced understanding of ecosystem functioning under …

Phenological Corrections To A Field-Scale, Et-Based Crop Stress Indicator: An Application To Yield Forecasting Across The U.S. Corn Belt, Yang Yang, Martha C. Anderson, Feng Gao, David M. Johnson, Yun Yang, Liang Sun, Wayne Dulaney, Christopher R. Hain, Jason A. Otkin, John Prueger, Tilden P. Meyers, Carl J. Bernacchi, Caitlin E. Moore

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Soil moisture deficiency is a major factor in determining crop yields in water-limited agricultural production regions. Evapotranspiration (ET), which consists of crop water use through transpiration and water loss through direct soil evaporation, is a good indicator of soil moisture availability and vegetation health. ET therefore has been an integral part of many yield estimation efforts. The Evaporative Stress Index (ESI) is an ET-based crop stress indicator that describes temporal anomalies in a normalized evapotranspiration metric as derived from satellite remote sensing. ESI has demonstrated the capacity to explain regional yield variability in water-limited regions. However, its performance in some …

Arbor Day Foundation Consulting Proposal, Katelyn Bonham, Grace Novak, Kayla Brumley, Amanda Purintun, Lauren Niesen, Sarah Rakes

Honors Program: Senior Projects (Public)

Over the course of one semester, our group has worked with the Arbor Day Foundation as part of the University of Nebraska-Lincoln College of Business Honors Academy. The Arbor Day Foundation is a local nonprofit conservation organization with a focus on trees. As consultants for the Arbor Day Foundation, our team discussed and observed the current needs of the company. We then developed creative solutions to address these needs, concentrating on Arbor Day’s Tree City USA program. Our solutions can be described utilizing the acronym “S.A.P.” which stands for “Segmentation”, “Awareness”, and “Portal”. These three recommendations build on each other …

Examining Spatial Inequality In Covid-19 Positivity Rates Across New York City Zip Codes, Tse-Chuan Yang, Seulki Kim, Yunhan Zhao, Seung-Won Emily Choi

Department of Sociology: Faculty Publications

We aim to understand the spatial inequality in Coronavirus disease 2019 (COVID-19) positivity rates across New York City (NYC) ZIP codes. Applying Bayesian spatial negative binomial models to a ZIP-code level dataset (N = 177) as of May 31st, 2020, we find that (1) the racial/ethnic minority groups are associated with COVID-19 positivity rates; (2) the percentages of remote workers are negatively associated with positivity rates, whereas older population and household size show a positive association; and (3) while ZIP codes in the Bronx and Queens have higher COVID-19 positivity rates, the strongest spatial effects are clustered in Brooklyn and …

Beauty And Lifestyle Subscription Services: A Modern Retailing Format For The Vigilante Collaborative Consumption Consumer, Melisa Spilinek

Department of Textiles, Merchandising and Fashion Design: Dissertations, Theses, and Student Research

Advancements in technology and ease of use of online shopping via phone applications (apps) and subscription services have fundamentally changed how consumers shop. Now more than ever, consumers are turning to time-saving technological tools that are subscription services. Subscription services provide a multitude of benefits to consumers and contribute to collaborative consumption in nearly every product and service category from coffee to apparel. To investigate beauty and lifestyle subscription services and collaborative consumption this study will utilize a mixed methods convergent design to analyze user experience including price sensitivity, subscription service apps and ease of use. Anticipated contributions to the …

Technology Leadership Qualities In Secondary School Principals In Nebraska Who Support Student-Led Social Media Teams, Jill M. Johnson

Department of Educational Administration: Dissertations, Theses, and Student Research

This study addresses secondary school principals in Nebraska who are dealing with the negative ramifications of their students’ social media interactions. To combat the problem, this study sought to identify the technology leadership qualities possessed by secondary school principals in Nebraska who support student-led social media teams. A purposeful sampling of six secondary school principals in Nebraska, who have all been practicing principals for at least three years, engaged in individual semi-structured interviews via Zoom in January 2021. The primary research question was: What technology leadership qualities are possessed by secondary school principals in Nebraska who support student-led social media …

An Intron Variant Of The Gli Family Zinc Finger 3 (Gli3) Gene Differentiates Resistance Training-Induced Muscle Fiber Hypertrophy In Younger Men, Christopher G. Vann, Robert W. Morton, Christopher B. Mobley, Ivan J. Vechetti, Brian K. Ferguson, Cody T. Haun, Shelby C. Osburn, Casey L. Sexton, Carlton D. Fox, Matthew A. Romero, Paul A. Roberson, Sara Y. Oikawa, Chris Mcglory, Kaelin C. Young, John J. Mccarthy, Stuart M. Phillips, Michael D. Roberts

Department of Nutrition and Health Sciences: Faculty Publications

We examined the association between genotype and resistance training-induced changes (12 wk) in dual x-ray energy absorptiometry (DXA)-derived lean soft tissue mass (LSTM) as well as muscle fiber cross-sectional area (fCSA; vastus lateralis; n = 109; age = 22 ± 2 y, BMI = 24.7 ± 3.1 kg/m2). Over 315 000 genetic polymorphisms were interrogated from muscle using DNA microarrays. First, a targeted investigation was performed where single nucleotide polymorphisms (SNP) identified from a systematic literature review were related to changes in LSTM and fCSA. Next, genome-wide association (GWA) studies were performed to reveal associations between novel SNP targets with …

Census Tracts, Racial Separation, And The Landscape Of Higher Education, Aaron Scholl

College of Business: Dissertations, Theses, and Student Research

This dissertation centers on research at the intersection of labor, public, and urban economics. Chapter 1 details the role, process, and history of census tract delineation prior to each Decennial Census, and investigates short- and long-run implications of neighborhoods that receive further delineation, or become “split”. Using a difference-in-differences empirical design, I exploit Decennial Censuses from 1980 to 2010 to find that “split” census tracts increase in their proportion of Black residents and these effects persist decades. Further evidence suggests that the Low-Income Housing Tax Credit program may play a role in concentrating residents in areas with greater census tract …

Prospective Predictors Of Receiving Disclosures Of Intimate Partner Violence And Sexual Assault Among College Students, Christina M. Dardis, Katie R. Davin, Lindsey M. Rodriguez, Emily R. Dworkin, Katie M. Edwards, Sarah E. Ullman, Emily A. Waterman

Department of Educational Psychology: Faculty Publications

Objective: Previous research has indicated that many undergraduates receive disclosures of sexual assault and intimate partner violence (IPV) from their peers; however, much of this research has been cross-sectional. The present study assessed the extent to which demographic characteristics and victimization history predicted whether participants received disclosures over the subsequent 6 months. Directional hypotheses assessed whether psychological symptoms and attitudes predicted, or were consequences of, disclosures at follow-up.

Method: College students (n = 867) from a broader treatment intervention study completed pretest (Time 1) and 6-month follow-up surveys (Time 2).

Results: Individuals who reported new disclosures at follow-up (56%) were …

Nitrogen Supply And Physical Disturbance Shapes Arctic Stream Nitrogen Uptake Through Effects On Metabolic Activity, Maria Myrstener, Steven A. Thomas, Reiner Giesler, Ryan A. Sponseller

School of Natural Resources: Faculty Publications

1. Climate change in the Arctic is altering the delivery of nutrients from terrestrial to aquatic ecosystems. The impact of these changes on downstream lakes and rivers is influenced by the capacity of small streams to retain such inputs. Given the potential for nutrient limitation in oligotrophic Arctic streams, biotic demand should be high, unless harsh environmental conditions maintain low biomass standing stocks that limit nutrient uptake capacity.

2. We assessed the drivers of nutrient uptake in two contrasting headwater environments in Arctic Sweden: one stream draining upland tundra and the other draining an alluvial valley with birch forest. At …

The Lycaenid Butterfly Fauna (Lepidoptera) Of Cosñipata, Peru: Annotated Checklist, Elevational Patterns, And Rarity, Gerardo Lamas, Michael L. Mcinnis, Robert C. Busby, Robert K. Robbins

Insecta Mundi

Peru’s Cosñipata Region in Cuzco and Madre de Dios Departments is a valley between Manu National Park and the Amarakaeri Communal Reserve that ranges from 400 to 4,000 m elevation. A team of experienced lepidopterists sampled the butterfly fauna of this valley for more than a decade (7,440 field person-hours). We analyze the data for Lycaenidae (Lepidoptera: Papilionoidea), a family for which we have taxonomic expertise. After adding data on the fauna from museums and the literature, we present an annotated checklist of the 340 Lycaenidae species recorded from the Cosñipata Region with notes for each species on the elevations …

Polarimetric Radar Characteristics Of Tornadogenesis Failure In Supercell Thunderstorms, Matthew S. Van Den Broeke

Department of Earth and Atmospheric Sciences: Faculty Publications

Many nontornadic supercell storms have times when they appear to be moving toward tornadogenesis, including the development of a strong low-level vortex, but never end up producing a tornado. These tornadogenesis failure (TGF) episodes can be a substantial challenge to operational meteorologists. In this study, a sample of 32 pre-tornadic and 36 pre-TGF supercells is examined in the 30 min pre-tornadogenesis or pre-TGF period to explore the feasibility of using polarimetric radar metrics to highlight storms with larger tornadogenesis potential in the near-term. Overall the results indicate few strong distinguishers of pre-tornadic storms. Differential reflectivity (Z_DR) arc size …

Lutz Strategic Analysis, Ashley Tyler

Honors Program: Senior Projects (Public)

Lutz, an accounting firm in Nebraska, was founded in 1980 and has grown radically since. It now has four divisions – Accounting, Finance, Talent, and Technology – and over 275 employees. When analyzing the external environment, a PESTEL, Porter’s Five Forces, and SWOT analyses were done. These found the external environment can have an impact on the industry, however, accounting is a job that will always be needed, and growth is almost always available. Lutz’s current strategy for growth is a resource-based view of the firm that involves being a one-stop-shop for customers. It is also looking for new firms …

Variants At The Asip Locus Contribute To Coat Color Darkening In Nellore Cattle, Beatriz B. Trigo, Adam T.H Utsunomiya, Alvaro A.A.D. Fortunato, Marco Milanesi, Rafaela B.P. Torrecilha, Harrison Lamb, Loan Nguyen, Elizabeth M. Ross, Ben Hayes, Romulo C.M. Padula, Thayla S. Sussai, Ludmilla B. Zabarez, Rafael S. Cipriano, Maria M.T. Caminhas, Flavia L. Lopes, Cassiano Pelle, Tosso Leeb, Danika Bannasch, Derek Bickhart, Timothy P.L. Smith, Tad S. Sonstegard, Jose F. Garcia, Yuri T. Utsunomiya

Roman L. Hruska U.S. Meat Animal Research Center: Reports

Background: Nellore cattle (Bos indicus) are well-known for their adaptation to warm and humid environments. Hair length and coat color may impact heat tolerance. The Nellore breed has been strongly selected for white coat, but bulls generally exhibit darker hair ranging from light grey to black on the head, neck, hump, and knees. Given the potential contribution of coat color variation to the adaptation of cattle populations to tropical and sub-tropical environments, our aim was to map positional and functional candidate genetic variants associated with darkness of hair coat (DHC) in Nellore bulls. Results: We performed a genome-wide association study …

Special Issue “Cfd Modeling Of Complex Chemical Processes: Multiscale And Multiphysics Challenges”, Li Xi, De-Wei Yin, Jae Sung Park

Department of Mechanical and Materials Engineering: Faculty Publications

No abstract provided.

Bioaccumulation And Partitioning Of Heavy Metals In Cicindelidia Haemorrhagica In Yellowstone National Park, Monica Gotschall

School of Natural Resources: Dissertations, Theses, and Student Research

The tiger beetle Cicindelidia haemorrhagica (Coleoptera: Cicindelidae) are widely distributed in Yellowstone National Park (YNP) and exclusively living on thermal areas. Heavy metals including arsenic, copper, lead, and selenium are present in these thermal springs, presenting an unique environment for C. haemorrhagica. Therefore, from 2018 – 2020 I sampled adult C. haemorrhagica from YNP and adult C. haemorrhagica from a known population in a salt flat in Idaho not associated with a hot spring and measured heavy metal concentrations. All populations of C. haemorrhagica bioaccumulated heavy metals. Cuticular waxes showed small concentrations of metals indicating that those metals are …

How Do Vanhorniidae (Hymenoptera) Parasitize Eucnemidae (Coleoptera)?, Jyrki Muona

Insecta Mundi

The relationship between the beetle family Eucnemidae and the parasitic proctotrupoid family Vanhorniidae is discussed. The only proven host for Vanhornia eucnemidarum Crawford in North America is an undetermined species of the genus Isorhipis Boisduval and Lacordaire. In Europe, the only known host for Vanhornia leileri Hedqvist is Hylis cariniceps (Reitter). The biologies of the hosts differ radically and it ap­pears unlikely that they could be parasitized in a typical proctotrupoid fashion in which eggs are placed in or on the host larva. This supports the hypothesis that small Vanhorniidae larvae attach themselves to the newly hatched beetle larvae, before …

Europium Sulfide Nanoprobes Predict Antiretroviral Drug Delivery Into Hiv-1 Cell And Tissue Reservoirs, Jonathan Herskovitz, Mahmudul Hasan, Jatin Machhi, Insiya Mukadam, Brendan M. Ottemann, James R. Hilaire, Christopher Woldstad, Joellyn Mcmillan, Yutong Liu, Javier Seravalli, Anandakumar Sarella, Howard E. Gendelman, Bhavesh D. Kevadiya

Department of Biochemistry: Faculty Publications

Background: Delivery of long-acting nanoformulated antiretroviral drugs (ARVs) to human immunodeficiency virus type one cell and tissue reservoirs underlies next generation antiretroviral therapeutics. Nanotheranostics, comprised of trackable nanoparticle adjuncts, can facilitate ARV delivery through real-time drug tracking made possible through bioimaging platforms. Methods: To model HIV-1 therapeutic delivery, europium sulfide (EuS) nanoprobes were developed, characterized and then deployed to cells, tissues, and rodents. Tests were performed with nanoformulated rilpivirine (NRPV), a non-nucleoside reverse transcriptase inhibitor (NNRTI) used clinically to suppress or prevent HIV-1 infection. First, CD4+ T cells and monocyte-derived macrophages were EuS-treated with and without endocytic blockers to identify …

Origin Of Agricultural Plant Pathogens: Diversity And Pathogenicity Of Rhizoctonia Fungi Associated With Native Prairie Grasses In The Sandhills Of Nebraska, Srikanth Kodati, Anthony O. Adesemoye, Gary Y. Yuen, Jerry Volesky, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

The Sandhills of Nebraska is a complex ecosystem, covering 50,000 km² in central and western Nebraska and predominantly of virgin grassland. Grasslands are the most widespread vegetation in the U.S. and once dominated regions are currently cultivated croplands, so it stands to reason that some of the current plant pathogens of cultivated crops originated from grasslands, particularly soilborne plant pathogens. The anamorphic genus Rhizoctonia includes genetically diverse organisms that are known to be necrotrophic fungal pathogens, saprophytes, mycorrhiza of orchids, and biocontrol agents. This study aimed to evaluate the diversity of Rhizoctonia spp. on four native grasses in the …

The Ungovernable Novel: Towards A New Political Imaginary, Joseph Turner

Department of English: Dissertations, Theses, and Student Research

The primary objective of my thesis is to provide an initial definition of what we could call the “ungovernable novel.” I borrow the concept of the “ungovernable” from the field of political theory, and I apply it to the theory of the novel by way of an engagement of Mikhail Bakhtin’s and Georg Lukács’ theories of the novel. Building on this theoretical foundation, I argue that our contemporary political imagination has reached a historical juncture: we must abandon the dystopian framework that we have inherited from the Cold War, and we must move in the direction of the ungovernable novel. …

Early Satellite Cell Communication Creates A Permissive Environment For Long-Term Muscle Growth, Kevin A. Murach, Bailey D. Peck, Robert A. Policastro, Ivan J. Vechetti, Douglas W. Van Pelt, Cory M. Dungan, Lance T. Denes, Xu Fu, Camille R. Brightwell, Gabriel E. Zentner, Esther E. Dupont-Versteegden, Christopher I. Richards, Jeramiah J. Smith, Christopher S. Fry, John J. Mccarthy, Charlotte A. Peterson

Department of Nutrition and Health Sciences: Faculty Publications

Using in vivo muscle stem cell (satellite cell)-specific extracellular vesicle (EV) tracking, satellite cell depletion, in vitro cell culture, and single-cell RNA sequencing, we show satellite cells communicate with other cells in skeletal muscle during mechanical overload. Early satellite cell EV communication primes the muscle milieu for proper long-term extracellular matrix (ECM) deposition and is sufficient to support sustained hypertrophy in adult mice, even in the absence of fusion to muscle fibers. Satellite cells modulate chemokine gene expression across cell types within the first few days of loading, and EV delivery of miR 206 to fibrogenic cells represses Wisp1 expression …

The Analysis Of Groundwater Recharge In Mongolia Using Vadose Zone Modeling, Khulan Batsukh

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Knowledge of groundwater recharge (GR) is vital for optimal water resources management under an arid continental climate. However, in vast territories such as Mongolia, direct measurements of GR are unfeasible because they mandate excessive costs, stemming from time-consuming and labor-demanding efforts. A valid alternative to direct measurements is numerical models based on the monitoring of precipitation (P) and evapotranspiration (ET) for simulating GR. While direct measurements of ET are logistically problematic and unpractical for large-scale applications, a reliable prediction may be derived from crop reference evapotranspiration (ET₀) which is calculable …

Phenotypic Plasticity Of Diverse Sorghum Varieties In Response To Nitrogen Deficit Stress, Mackenzie Zwiener

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The movement of nutrients from old vegetative tissue to young leaves and reproductive organs is known as senescence. Senescence can be influenced by the environment of a plant, such as, drought, heat, and nutrient stress. These environmental stressors can also influence canopy architecture. Crop canopy consists of several traits including: leaf number, angle, length and width. Past research in crops like maize and rice have shown significant influences of more erect leaves, including, the ability for increased planting density, which optimizes light interception and increases yield. In a field trial of a sorghum association panel including 345 different sorghum varieties …

Quantification Of The Mincer Et Al. 1993 Method Of Age Estimation For The Purpose Of Increasing The Reliability And Accuracy Of Scores Within The System, Bailey Oettel

Department of Anthropology: Theses and Student Research

There is currently a need to test new methods of increasing the accuracy and reliability of the stages scored by users of subjective methodologies within the forensic sciences. One way this can be done is through the quantification of these subjective stages through metric measurements and the application of sectioning points. This research assesses the quantification of the subjective stages within the Mincer et al. (1993) method of age estimation through odontometric measurements and the application of sectioning points. In this study, five odontometric measurements taken from radiographs of fifty-five third mandibular molars from thirty-nine individuals were used to establish …

Saturated Free Fatty Acids Induce Placental Trophoblast Lipoapoptosis, Sathish Kumar Natarajan, Taylor Bruett, Philma Glora Muthuraj, Prakash K. Sahoo, Jillian Power, Justin L. Mott, Corrine Hanson, Ann Anderson-Berry

Department of Nutrition and Health Sciences: Faculty Publications

Obesity during pregnancy increases the risk for maternal complications like gestational diabetes, preeclampsia, and maternal inflammation. Maternal obesity also increases the risk of childhood obesity, intrauterine growth restriction (IUGR) and diabetes to the offspring. Increased circulating free fatty acids (FFAs) in obesity due to adipose tissue lipolysis induces lipoapoptosis to hepatocytes, cholangiocytes, and pancreatic-β-cells. During the third trimester of human pregnancy, there is an increase in maternal lipolysis and release of FFAs into the circulation. It is currently unknown if increased FFAs during gestation as a result of maternal obesity cause placental cell lipoapoptosis. Increased exposure of FFAs during maternal …

Preclinical Development Of Single Walled Carbon Nanotube-Based Optical Biosensors, Eric M. Hofferber

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

High resolution, long-term monitoring of key biological analytes would improve patient outcomes by providing earlier detection of disease states and improved efficacy of treatment. One class of biosensors that have gained much attention in recent years are optical biosensors. Optical probes are attractive biosensors due to their noninvasive nature of detection, as certain light can pass through tissue, water, and blood. Single walled carbon nanotubes (SWNT) are a specific type of optical biosensor that fluoresce in the near infrared range of the electromagnetic spectrum and offer unparalleled spatial and temporal resolution. SWNT have been applied as biosensors in vitro, …

Surface Functionalization Of Elastomers For Tunable Crystal Growth And Smart Adhesives, John Kapitan

Department of Chemistry: Dissertations, Theses, and Student Research

Silicone rubbers have seen extensive work on modulation of their surface environments for use in microfluidics, cell adhesion, and sensing. Most surface procedures utilize a common initial step of oxidation of the surface to increase the number of active surface functional groups. Following oxidation more permanent functionalities can be imparted on the surface using silanization, grafting polymer brushes, or creating ionic bonds to the surface. Of these three, silanization proves to be the most pervasive due to the range of procedures available and how easy the procedures prove to be. However, the mechanism by which silanization is performed heavily involves …

Essays On Agricultural Technology, Resource Allocation And The Value Of Information, Pedro W. Vertino De Queiroz

Department of Agricultural Economics: Dissertations, Theses, and Student Research

This dissertation studied the adoption of agricultural technologies and the value of information for the allocation of resources in agriculture. Chapter 1 studied traditional (e.g., land and labor) and commercial (e.g., machinery and fertilizers) inputs in South American agriculture. Acemoglu’s directed technical change was used to estimate the process of induced innovation using deforestation as source of exogenous variation for the agricultural land supply. The results indicated that larger availability of land in intensive deforestation countries caused more land-complementary inputs (machinery) to be used relative to labor-complementary inputs (fertilizers). Technical change was biased towards land. Chapter 2 studied nitrogen fertilizer …