Digital Commons Network^™

Acid-Base Regulation Mechanisms In The West African Lungfish Protopterus Annectens: An Investigation Into The Role Of The Sodium Proton Exchanger (Nhe), Victor H. Q. Pham-Ho Msc

Theses and Dissertations (Comprehensive)

The lungfish possesses a primitive lung and underdeveloped gills, making use of bimodal respiration. Like other freshwater fishes they must regulate ion- and acid-base equilibrium through active ion uptake (driven by pumps and ion transporters), albeit with challenges due to their underdeveloped gills. My thesis aimed to elucidate the role of the sodium proton exchangers (NHE), encoded by the genes slc9a1/nhe1, slc9a2/nhe2 and slc9a3/nhe3, which are hypothesized to contribute towards acid-base regulation. Pharmacologically, amiloride, a sodium-transport inhibitor, and 5-(N-Ethyl N-isopropyl)-Amiloride (EIPA), an NHE specific inhibitor, affected whole-animal titratable acidity and ammonia fluxes, supporting a physiological function of the NHE. Next, …

Evops: Evolutionary Patch Selection In The Embedding Space Of Whole Slide Images, Saya Hashemian

Theses and Dissertations (Comprehensive)

Computational pathology increasingly relies on the analysis of Whole-Slide Images (WSIs), which capture tissue specimens at gigapixel resolution. Because a single slide is far too large to process directly, the

prevailing paradigm decomposes each WSI into thousands of small patches and encodes them as high- dimensional feature embeddings using deep learning backbones. While effective, this paradigm carries a

substantial cost: the resulting collections of patch embeddings are computationally expensive to store and process, and they are frequently dominated by redundant, homogeneous, or otherwise uninformative tissue regions that dilute the diagnostic signal. Existing patch selection methods largely depend on heuristic or …

Eat With Understanding: A Um Student Guide To Food Systems, James Deacon, Cora Johnson, Lucas Dymit, Kaeli Rackham, Elsie Danyo

Undergraduate Theses, Professional Papers, and Capstone Artifacts

The industrialized food system creates environmental harm, reduces food sovereignty, and contributes to growing food insecurity. These problems oftentimes are overlooked in higher education. To address this gap, our project examines how access to sustainable food education and campus-community partnerships can improve well-being and informed decision-making amongst University of Montana students. This collaborative project connects partners within UM Wellness, PEAS Farm, the Missoula Food Bank and Community Center, and the Big Sky Culinary Institute. Our research includes applied learning with these organizations by hosting a variety of speaker series presentations and coordinating a cooking workshop. We collected quantitative and qualitative …

Independent Animal Chiropractic Practice: An Evidence-Based Argument For Autonomy Beyond Veterinary Supervision, Montana Adams

Undergraduate Honors Theses

Animal chiropractic is a growing form of conservative care used to improve mobility, reduce pain, and support neuromusculoskeletal function in animals. Despite evidence suggesting it is both effective and low risk, access remains limited due to inconsistent state regulations. Many jurisdictions require chiropractors to obtain veterinary supervision, referral, or licensure, even when they have completed specialized training and certification in animal chiropractic. This paper evaluates the effectiveness and safety of animal chiropractic while analyzing the impact of current regulatory policies. Research indicates that chiropractic care can improve mobility and reduce spinal conditions in animals when performed by trained professionals. However, …

Excess Nitric Oxide Alters Cellular Ph To Restrict Salicylic Acid Movement And Systemic Immunity, Fan Xia, Huazhen Liu, Keshun Yu, Xinyu Yuan, Aardra Kachroo, Pradeep Kachroo

Plant Pathology Faculty Publications

Plants carrying a mutation in S-nitrosoglutathione reductase 1 (GSNOR1) accumulate high nitric oxide (NO) and exhibit impaired immunity characterized by reduced pathogen-responsive salicylic acid (SA) accumulation and failure to activate normal SA signaling. We show that this reduced SA responsiveness in gsnor1 plants arises from impaired vascular-associated movement of SA, thereby compromising systemic acquired resistance (SAR). Elevated NO perturbs cellular pH homeostasis, acidifying the apoplast and alkalinizing the cytosol, which likely interferes with phloem-associated SA movement and renders gsnor1 plants unresponsive to foliar SA. In contrast, SA supplied via root drench restores SA signaling and SAR in gsnor1, …

Genomic Characterization Of A Novel Bloom-Forming Cyanobacterial Species From Western Kansas., Louisa Acquah

Master's Theses or Doctor of Nursing Practice

Harmful cyanobacterial blooms are a danger to freshwater systems, particularly in water limited regions such as western Kansas, yet the genetic identity and diversity of bloom-forming taxa in this region remain poorly characterized. In this study, I investigated a cyanobacterial bloom in Horsethief Reservoir (Kansas, USA) in summer 2024 with the aim of resolving the taxonomic identity and genomic features of the dominant organism. Bloom water samples were collected, and the dominant cyanobacterium was enriched and rendered nearly axenic through controlled cultivation and repeated subculturing. Preliminary 16S rRNA gene sequencing indicated affiliation with the genus Limnothrix, but with notable …

Exploring The Link Between Soil Microbes, And Land Use Through A One Health Lens, Yaw A. Antwi

Master's Theses or Doctor of Nursing Practice

The diversity of microbes within the soil plays an essential role in soil ecosystem

functioning. However, these microbes may also serve as environmental reservoirs for antibiotic resistance genes. The study examined the diversity of bacteria that are found in soil across Rural/Agricultural and Rural/Nonagricultural landscapes within some selected counties in Kansas and its associated antibiotic resistance genes taxa. A total of twenty-four soil samples was collected and analyzed using 16S rRNA gene amplicon sequencing which targeted the V3-V4 regions. Statistical analysis revealed that the alpha diversity metrics (Chao1 richness and Shannon evenness) showed no significant difference in microbial structure (p=0.693, …

Bayesian Multivariate Modelling Of Lone Star (Amblyomma Americanum) Tick Life Stage Abundance And Temporal Trends To Inform Public Health Risk In Virginia, Thabo Lephoto, Henry Mwambi, Oliver Bodhlyera, Holly Gaff

Biological Sciences Faculty Publications

The increasing abundance of ticks poses a growing public health concern due to heightened human exposure to tick bites. The lone star tick (Amblyomma americanum: Ixodida: Ixodidae), a common human-biting species in the United States, has expanded its range in recent years. However, how its different life stages vary across time, habitats, and locations remains insufficiently understood. We analyzed tick abundance data collected in southeastern Virginia between 2009 and 2018, focusing on larval, nymphal, and adult life stages. A Bayesian multivariate modelling framework was used to examine seasonal patterns, habitat effects, spatial variation, and biological links between life stages. Two …

An Ensemble Classifier For Ordinal Outcomes In High-Dimensional Genomics Data, Heranga K. Rathnasekara, Sinjini Sikdar

Mathematics & Statistics Faculty Publications

Analysis of genomics data for predicting disease outcomes is a fast-growing field in medical research. There often exist categorical, specifically, ordinal outcomes that need to be predicted based on genomic profiles. This has led to recent development of some high-dimensional ordinal classification methods that can address the large dimensionality of the genomic covariate set. These high-dimensional ordinal models tend to vary widely in their performance depending on the data they are applied to and the evaluation criteria used. In this article, we outline an ensemble ordinal classifier that integrates different ordinal modeling approaches through bootstrap-based model evaluation, multi-metric performance assessment, …

Three Decades Of Classifying Threatened Species: Lessons Learned From And About The Iucn Red List Criteria For Quantifying Extinction Risk, H. Resit Akçakaya, E. J. Milner-Gulland, Mike Hoffmann, Helen M. Regan, Ilona Naujokaitis-Lewis, Andre E. Punt, Kevin J. Gaston, David A. Keith, Stuart H. M. Butchart, Simon N. Stuart, Nigel J. Collar, Moreno Di Marco, Monika Bohm, Alex J. Berryman, David P. Mallon, Axel Hochkirch, Nicholas K. Dulvy, Malin Rivers, Thomas M. Brooks, James R. S. Westrip, Jonathan Paul Rodriguez, Craig Hilton-Taylor, Janet Scott, Simon Tarr, Sophie H. Ledger, Christi Linardich

Biological Sciences Faculty Publications

The IUCN Red List of Threatened Species, the most widely used global system for assessing species' extinction risk, has become a foundational source of information for conservation management, policy and research. Since the adoption of quantitative extinction risk criteria more than three decades ago, the Red List has expanded substantially in scope and influence, informing decisions ranging from species conservation and protected area designation to international agreements, corporate risk assessments and global biodiversity indicators. Given its central role, maintaining scientific rigour, transparency and trust in the Red List system is essential. Feedback from users, emerging from evolving applications and scientific …

Characterization Of Phytoplankton-Excreted Metabolites Mediating Carbon Flux Through The Surface Ocean, Yuting Zhu, Hanna S. Anderson, Eli Salcedo, Samuel E. Miller, Krista Longnecker, Melissa C. Kido Soule, Sheean T. Haley, Gretchen J. Swarr, Rogier Braakman, Sonya T. Dyhrman, Elizabeth B. Kujawinski

Chemistry & Biochemistry Faculty Publications

The marine labile dissolved organic carbon (DOC) pool is a dynamic reservoir of thousands of molecules that cycles approximately one-quarter of Earth’s primary production within days to weeks. After excretion by phytoplankton and other microbes, metabolites are rapidly consumed, resulting in low standing concentrations (picomolar to low nanomolar). Despite the decades-long search for labile DOC sources and molecular identities, marine phytoplankton exometabolomes are not well characterized, largely due to difficulties in measuring small polar molecules in saline water. Here, we profiled the exometabolomes of six axenic phytoplankton species representing key functional groups including a diatom (Thalassiosira pseudonana CCMP1335), a …

[Review Of The Book A Conspectus Of The North American Isoetaceae, By D. F. Brunton, J. T. Kartesz, M. Nishino, And P. C. Sokoloff]., Lytton John Musselman

Biological Sciences Faculty Publications

Isoetes (Isoetaceae; Lycopodiopsida; quillworts) constitutes a highly successful, cosmopolitan genus with over 200 species. Isoetes is derived from isos Greek for equal and eter for year, referring to the typically long persisting leaves of the sole genus in this ancient plant family. The leaves resemble a ‘quill-of-feather,’ hence the common name ‘Quillworts,’ wort, from old Germanic wurti, meaning plant. In large measure due to its simple form, inconspicuous appearance and negligible economic value, it represents one of the least studied and least collected of all North American genera. Isoetes constitutes a taxonomically enigmatic group with numerous polyploid species that arose …

Land Use Influences Dissolved Organic Matter Composition In The U.S. Coastal Critical Zone Network, Aleksandar I. Goranov, Elizabeth V. Whitney, Brian R. Moyer, Katherine L. Tully, Patrick G. Hatcher, Yu-Ping Chhin

Chemistry & Biochemistry Faculty Publications

Coastal watersheds are highly productive biogeochemical systems supporting robust coastal fisheries and contributing significantly to the marine gross primary production flux. These ecosystems are comprised of civil infrastructure, farms, forests, and marshes, and their diversity is reflected in the quantity and quality of dissolved organic matter (DOM). Here, we assess the role of farming in influencing DOM from surface waters of six coastal tidal creeks adjacent to forest and farm sites in the US Critical Zone Network. Molecular fingerprinting using electrospray ionization - Fourier transform - ion cyclotron resonance - mass spectrometry revealed that farm-influenced DOM was enriched in nitrogen-, …

Granulomatous Cellular Signatures In Nontuberculous And Tuberculous Mycobacterial Infections, Brianna M. Doratt, Ethan G. Napier, Mahdi Eskandarian Boroujeni, Sarah Douglas, Michael H. Davies, Luiz Bermudez, Eliot Spindel, Erin F. Mccaffrey, Ilhem Messaoudi

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Mycobacterium tuberculosis (Mtb) and nontuberculous mycobacteria (NTM) are acid-fast bacilli that trigger granuloma formation, a hallmark immune response aimed at containing infection. While the biology of Mtb granulomas has been widely investigated, far less is known about granulomas caused by NTM infection, despite the increasing prevalence and clinical challenge of NTM cases worldwide. Because granulomas influence infection control, pathology, and treatment response, understanding their cellular organization and signaling is critical to improving therapeutic strategies. Therefore, we characterized granulomas formed following infection of rhesus macaques with Mycobacterium avium subsp. hominissuis (MAH) and compared them to granulomas from cynomolgus macaques infected with …

A Framework For Characterizing The Peripheral Immune Isonome Using Long-Read Single-Cell Rna Sequencing And Its Relevance To Neurological Disease, Patricia Hayes Doyle

Theses and Dissertations--Neuroscience

Long-read single-cell RNA sequencing provides an opportunity to understand human health and disease at isoform resolution, revealing cellular diversity and disease mechanisms difficult to resolve with bulk or short-read methodologies.

Using a modified PIPseq workflow and computational pipeline adapted for Oxford Nanopore (ONT) sequencing, we profiled isoform usage across immune cells, integrating marker expression and isoform discovery, generating the largest long-read single-cell dataset of human immune cells from a single individual to date. We identified non-canonical protein-coding variants of GZMB and CD3G enriched in unexpected cell types. We also discovered novel transcripts from CMC1 and LYAR with cell-type-specific signatures that …

Exploring The Limitations Of Substrate Scope In Dimethylallyltryptophan Synthases, Evan T. Miller

Theses and Dissertations--Pharmacy

Natural products (NPs), are the largest source of bioactive compounds in Nature, and are essential to the treatment of human disease. Nearly 50% of drugs approved for use from 1981 to 2019 owe some aspect of their development to NPs, either in terms of their structure, pharmacophore, or mechanism of action. However, NPs are difficult to structurally optimize. Chemoenzymatic methods for NP derivatization have been increasingly seen as practical alternatives to traditional synthetic methods. Prenyltransferases (PTs) are involved in the primary and secondary metabolism of plants, bacteria, and fungi, and they are key enzymes in the biosynthesis of many clinically …

A Tale Of Two Serpins: Pathologic And Protective Roles Of Agt And Pai-1 In Metabolic And Cardiovascular Disease, Alex C. Pettey

Theses and Dissertations--Physiology

Metabolic and cardiovascular diseases are leading causes of morbidity and mortality worldwide. Conditions such as metabolic dysfunction-associated steatotic liver disease (MASLD), aortic aneurysm, and cardiac fibrosis have limited pharmacological therapies, underscoring the need for deeper mechanistic investigations. Serine protease inhibitors (serpins) have been implicated in these pathologies and represent potential therapeutic targets. Despite structural homology, serpins regulate diverse physiological processes through both protease inhibition and non-inhibitory mechanisms. This dissertation examines the roles of two serpins, angiotensinogen (AGT) and plasminogen activator inhibitor-1 (PAI-1), in preclinical models of metabolic and cardiovascular disease to identify novel mechanisms that may inform future therapeutic strategies. …

Using Camera-Based Unmarked Spatial Capture-Recapture Modeling To Estimate Reintroduced Elk (Cervus Canadensis) Population Parameters And Distribution In Southeastern Kentucky, Claire Marie Muia

Theses and Dissertations--Forestry and Natural Resources

Estimation of population parameters is important for wildlife management decisions. Elk reintroduced to southeastern Kentucky experienced early irruptive population growth and are currently monitored using a statewide harvest-based statistical population reconstruction model (SPR) across the Kentucky Elk Restoration Zone (KERZ). Because the SPR model is spatially coarse and difficult to scale to the smaller management units comprising the KERZ, we conducted a spatially explicit capture-recapture study using a clustered camera-trapping array deployed for 10 weeks from June–August 2024 to estimate elk population parameters within Management Unit 4. Due to a lack of resights of GPS-marked elk, population parameters were estimated …

Understanding Knowledge And Perceptions Of The Beef Industry On A Land-Grant University Campus, Allison E. Reaves

Theses and Dissertations--Community & Leadership Development

A well-researched phenomenon in the agricultural industry is the effects of constant innovation coupled with an increasing divide between producer and consumer. This issue has been presented as especially prevalent within animal agriculture and the beef industry, a predominant concern considering Kentucky’s agricultural commodities. This study (n = 31) utilized a mixed-methods approach to understand the knowledge, perceptions, and behavior of beef consumers on a land-grant university campus. Methodologies included Python’s DeepFace emotion recognition, semi-structured interviews, and the JMALI agricultural literacy assessment. Findings revealed participants to be below expected agricultural literacy levels of high school graduates (M=11), with no …

Severity And Duration-Dependent Aortic Stiffening In A Rabbit Coarctation Model Identifies Constitutive Material Parameters As Promising Regional Biomarkers For Hypertension Progression, Arash Ghorbannia, Jamasp Azarnoosh, John F. Ladisa Jr.

VMASC Publications

Coarctation of the aorta (CoA) alters hemodynamics and drives regional remodeling, yet the influence of severity and duration on constitutive properties is undefined. We quantified mechanical responses from CoA to identify constitutive parameters capturing stiffening across clinical severities and durations. Mild (≤ 12 mmHg), intermediate (13–20 mmHg), and severe (> 20 mmHg) CoA was created in rabbits for short, long, and prolonged durations (~ 1, 3, or 22 weeks, respectively). Stress–stretch curves from proximal and distal regions were fit with multiple constitutive models (Linear Elastic, Neo-Hookean, Yeoh, Ogden, Mooney–Rivlin, Holzapfel). Model performance was evaluated by normalized RMSE and R², with …

Hsp90 Inhibitor, At13387 Mitigates Chronic Lung Injury In Pre-Pubertal Mice: A Therapeutic Axis In Bronchopulmonary Dysplasia, Pavel A. Solopov, Christiana Dimitropoulou, John D. Catravas, Ruben M. L. Colunga Biancatelli

Bioelectrics Publications

Exposure to hydrochloric acid (HCl) can provoke severe chronic pulmonary injury. Children are particularly vulnerable due to their smaller airways, higher respiratory rate, and stronger inflammatory response; yet no countermeasures exist for HCl-induced chronic lung injury in the pediatric population. We have previously demonstrated the involvement of HSP90 during HCl-induced lung injury in pre-pubertal (p24) mice, who develop stronger persistent inflammation with higher NLRP3 inflammasome activation, but less pulmonary fibrosis compared to adults. Here, we tested the hypothesis that post-treatment with the second-generation HSP90 inhibitor AT13387 (Onalespib), administered subcutaneously beginning 24 h after HCl instillation, would prevent HCl-induced chronic lung …

Arkansas Corn And Grain Sorghum Performance Tests 2025, J. F. Carlin, J. P. Kelley, T. N. Spurlock, T. D. Swanson, R. D. Bond, J. C. Mccoy, C. J. Bulloch

Arkansas Agricultural Experiment Station Research Series

Report Statement This Arkansas Agricultural Experiment Station (AAES) publication summarizes variety trial research conducted by the Arkansas Crop Variety Improvement Program. Variety trial information presented here furthers the AAES mission of conducting research that benefits the citizens of Arkansas by expanding agricultural profitability and strengthening local and state economies. This information is not a recommendation or an endorsement of any product by the University of Arkansas System Division of Agriculture or AAES. Recommendations interpreted from this information are made and presented by the Arkansas Cooperative Extension Service.

Corn and grain sorghum performance tests are conducted each year in Arkansas by …

Microbial Community Structure In Global Soils, Matthew Jabro

CMC Senior Theses

Soil harbors the most diverse microbial communities on Earth, yet whether predictable community types exist across biomes and whether taxonomic composition encodes habitat of origin remain open questions at global scale. This thesis addresses both questions by applying unsupervised clustering and supervised classification to transformed 16S ribosomal RNA (rRNA) amplicon profiles from two independent datasets: the global topsoil survey of Bahram et al. (193 samples) and the Earth Microbiome Project (EMP) soil subset of Thompson et al. (2,209 samples). Application of a sample clustering method based on a mixture of Gaussian Graphical Models (MixGGM) identified 19 clusters in the topsoil …

Neuroimaging Correlates Of Differences In Learning From Repeated Probabilistic Outcomes, Allison E. Rudolph

CMC Senior Theses

Learning from experience requires integrating feedback over time, yet individuals vary widely in how effectively they extract structure from probabilistic environments. This study examined how such variability relates to neural responses in the ventral striatum (vStr), caudate nucleus, hippocampus, and medial prefrontal cortex (mPFC). Seventy-four participants across childhood, adolescence, and adulthood completed a modified Iowa Gambling Task during fMRI scanning, choosing whether to play or pass on four machines differing in expected value and variance. Behavioral learning slopes, calculated across six runs for each machine, were used to classify participants as learners or non-learners. Learners showed clearer improvement over time …

Reframing Sexual Assault And Intimate Partner Violence Through A Maternal And Child Health Lens: Implications For Integrated Prevention, Policy, And Practice, Daija C. Gibson

Theses and Dissertations

Sexual assault and intimate partner violence remain persistent public health concerns in the United States, with significant consequences for individual health, family stability, and population well-being. Although these forms of violence are frequently addressed through criminal justice and behavioral health frameworks, less attention has been given to their implications within maternal and child health, where relational dynamics, life course development, and intergenerational outcomes are central. This study reframed SA and IPV as core MCH issues to examine how integrated, systems-based approaches can strengthen prevention efforts. A structured literature review and systematic synthesis of peer-reviewed studies published between 2015 and 2026 …

Evaluation Of Valley Healthcare System Inc. School-Based Health Clinic/Center At Dorothy I. Heights Elementary School In Columbus, Georgia, Nakia Ford

Theses and Dissertations

School-Based Health Centers (SBHCs) are an important strategy for addressing health disparities and improving educational outcomes among underserved students. In Columbus, Georgia, barriers such as limited insurance, transportation challenges, and provider shortages contribute to unmet health needs, which are linked to increased absenteeism. To address these issues, Valley Healthcare System, Inc. (VHCS) implemented a School-Based Health Clinic (SBHC) at Dorothy I. Heights Elementary School. This study evaluates the effectiveness of the SBHC in improving student attendance outcomes. A quasi-experimental, difference-in-differences design compared Dorothy I. Heights Elementary School (treatment group) before and after SBHC implementation (2021–2022 and 2022–2023) with a similar …

The Rna-Binding Protein Hur Modulates The Expression Of The Disease-Linked Ccl2 Rs1024611g-Rs13900t Haplotype, Feroz Akhtar, Joselin Hernandez-Ruiz, Ya-Guang Liu, Roy G. Resendez, Denis Feliers, Liza D. Morales, Alvaro Diaz-Badillo, Donna M. Lehman, Rector Arya, Juan Carlos Lopez-Alvarenga, John Blangero, Ravi Duggirala, Srinivas Mummidi

School of Medicine Publications

CC-chemokine ligand 2 (CCL2) is involved in the pathogenesis of several diseases associated with monocyte/macrophage recruitment, such as HIV-associated neurocognitive disorder (HAND), tuberculosis, and atherosclerosis. The rs1024611 (alleles: A>G; G is the risk allele) polymorphism in the CCL2 cis-regulatory region is associated with increased CCL2 expression in vitro and ex vivo, leukocyte mobilization in vivo, and deleterious disease outcomes. However, the molecular basis for the rs1024611-associated differential CCL2 expression remains poorly characterized. It is conceivable that genetic variant(s) in linkage disequilibrium (LD) with rs1024611 could mediate such effects. Previously, we used rs13900 (alleles: C>T) in the CCL2 …

Limosilactobacillus Reuteri Alleviates Proinflammatory T-Cell-Mediated Liver Injury And Transcriptomic Changes In Immunocompromised Mice, Ana Fadhel Alvarez, Zheng Yin, Beanna Okeugo, Alexander Banerjee, Meng Luo, Christopher M Taylor, Salomea Giorgberidze, Vaishali Harne, Rambabu Majji, Melissa N Munroe, Ji Ho Suh, Stephen T C Wong, Kang Ho Kim, Hari Krishna Yalamanchili, Suhair Al Salihi, Jon Marc Rhoads, Yuying Liu

Children’s Nutrition Research Center Staff Publications

Background: A deficiency of immunosuppressive regulatory T cells, as seen in scurfy (SF) mice or in IPEX syndrome in humans, can lead to multiorgan inflammation. Oral administration of the probiotic Limosilactobacillus reuteri Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSM) 17938 prolongs survival and reduces Th1- and Th2-associated inflammation in SF mice. It remains unclear how DSM 17938-educated SF-CD4+ T cells modulate T-cell-liver communication.

Methods: To characterize CD4+ T cells from SF mice orally administered DSM 17938 (Prob-SF-CD4+ T cells) and to compare them with CD4+ T cells from SF mice (SF-CD4+ T cells), cells isolated from SF spleens were …

How Semiflightless Birds Adapt: A Survey From Barú, Costa Rica, Eli P. Laloudakis

Scripps Senior Theses

When we think of birds, we think of flight. Because of this, scientific research often focuses on how birds evolved flight and how their wings function during flight. However, not all birds can fly or fly well, as wings wax and wane on developmental, seasonal, and evolutionary time scales (Dial and Heers 2021). Consequently, rudimentary wings can be found in developing birds, secondarily flightless or semiflightless birds, birds that undergo simultaneous molts, and extinct theropods with “protowings” (structures that preceded fully functional wings). Secondarily flightless and semiflightless birds often evolve where there is no/low predation, abundant year-round food supply, and …

Impacts Of Management Practices And Soil Properties On Free-Living Nitrogen Fixation In Eastern South Dakota, Laura Galvan Nuevo

Electronic Theses and Dissertations

Free-living nitrogen (N) fixation (FLNF) may represent a sustainable pathway to supplement crop N demand in agroecosystems, yet edaphic and management factors regulating this process under field conditions remain poorly understood in the Northern Great Plains. Using 15N2 direct method to quantify potential FLNF (pFLNF) and baseline FLNF (bFLNF), this thesis investigates how crop rotations (2-, 3-, and 4-year systems), tillage management (conventional vs. no-till), cover cropping, and soil properties affect the potential of free-living diazotrophs to supply N via FLNF in a long-term no-till corn-based system in Southeastern South Dakota. A two-year field study evaluated pFLNF across four growing …