Digital Commons Network^™

Analysis Of Task Performance During Radiological Surveillance By Means Of Discrete Event Simulation, Michael H. Ames

Theses and Dissertations

The surveillance and detection of radioactive contamination on surfaces and in the environment are commonly investigated by surveyors utilizing portable detection equipment. The availability of Discrete Event Simulation (DES) and Human Performance Modeling (HPM) allows for the analysis of physical and cognitive processes associated with these operations, as well as the effect that external environmental factors have on surveyor performance. This research uses the Improved Performance Research Integration Tool (IMPRINT) to approximate the performance of a radiological detection task informed by the observation of six surveyors. The effects of chemical Individual Protective Equipment (IPE) use is evaluated along with the …

Development Of A Methodology For The Quantification Of Reaerosolization Of A Biological Contaminant Surrogate Particle From Military Uniform Fabric, George D. Cooksey

Theses and Dissertations

During a mass casualty medical evacuation after a bioaerosol attack, a decontamination method is needed that is effective at both decontamination and preventing the secondary hazard of biological particles reaerosolizing from contaminated clothing. However, neither the efficacy of current decontamination methods nor the risk of biological particle reaerosolization is significantly explored in existing literature. The goals of this thesis were to develop a repeatable methodology to quantify the reaerosolization of a biological contaminate off Airman Battle Uniform (ABU) fabric swatches, and to test the efficacy of one decontamination method (high-volume, low-pressure water) using 1 mpolystyrene latex (PSL) spheres as a …

Telemetry Data Mining For Unmanned Aircraft Systems, Li Yu

Theses and Dissertations

With ever more data becoming available to the US Air Force, it is vital to develop effective methods to leverage this strategic asset. Machine learning (ML) techniques present a means of meeting this challenge, as these tools have demonstrated successful use in commercial applications. For this research, three ML methods were applied to a unmanned aircraft system (UAS) telemetry dataset with the aim of extracting useful insight related to phases of flight. It was shown that ML provides an advantage in exploratory data analysis and as well as classification of phases. Neural network models demonstrated the best performance with over …

Analyzing The Impact Of Blood Transfusion Kits And Triage Misclassification Errors For Military Medical Evacuation Dispatching Policies Via Approximate Dynamic Programming, Channel A. Rodriguez

Theses and Dissertations

Members of the armed forces greatly rely on having an effective and efficient medical evacuation (MEDEVAC) process for evacuating casualties from the battlefield to medical treatment facilities (MTF) during combat operations. This thesis examines the MEDEVAC dispatching problem and seeks to determine an optimal policy for dispatching a MEDEVAC unit, if any, when a 9-line MEDEVAC request arrives, taking into account triage classification errors and the possibility of having blood transfusion kits on board select MEDEVAC units. A discounted, infinite-horizon continuous-time Markov decision process (MDP) model is formulated to examine such problem and compare generated dispatching policies to the myopic …

The Impact Of Response To Iron Therapy On Maternal And Neonatal Outcomes Among Pregnant Women With Anemia, Sarah E Detlefs, Michael D Jochum, Bahram Salmanian, Jennifer R Mckinney, Kjersti M Aagaard

Faculty, Staff and Students Publications

BACKGROUND: Anemia during pregnancy is associated with increased risks of preterm birth, preeclampsia, cesarean delivery, and maternal morbidity. The most prevalent modifiable cause of pregnancy-associated anemia is iron deficiency. However, it is still unclear whether iron therapy can reduce the risks of adverse outcomes in women with anemia.

OBJECTIVE: This study aimed to determine whether response to iron therapy among women with anemia is associated with a change in odds of adverse maternal and neonatal outcomes.

STUDY DESIGN: This was a population-based cohort study (2011-2019) using an institutional database composed of obstetrical patients from 2 delivery hospitals. Patients with adequate …

Visual Pigment-Deficient Cones Survive And Mediate Visual Signaling Despite The Lack Of Outer Segments, Hui Xu, Nange Jin, Jen-Zen Chuang, Zhao Zhang, Xiaoyue Zhong, Zhijing Zhang, Ching-Hwa Sung, Christophe P Ribelayga, Yingbin Fu

Faculty, Staff and Students Publications

Rhodopsin and cone opsins are essential for light detection in vertebrate rods and cones, respectively. It is well established that rhodopsin is required for rod phototransduction, outer segment disk morphogenesis, and rod viability. However, the roles of cone opsins are less well understood. In this study, we adopted a loss-of-function approach to investigate the physiological roles of cone opsins in mice. We showed that cones lacking cone opsins do not form normal outer segments due to the lack of disk morphogenesis. Surprisingly, cone opsin-deficient cones survive for at least 12 mo, which is in stark contrast to the rapid rod …

A Call For An Integrated Approach To Improve Efficiency, Equity And Sustainability In Rare Disease Research In The United States, Meghan C Halley, Hadley Stevens Smith, Euan A Ashley, Aaron J Goldenberg, Holly K Tabor

Faculty, Staff and Students Publications

To build a more efficient, equitable, and sustainable approach to rare disease research in the United States, we must prioritize integrated research infrastructure and approaches that focus on understanding connections across rare diseases.

Clinical Exome Sequencing Data Reveal High Diagnostic Yields For Congenital Diaphragmatic Hernia Plus (Cdh+) And New Phenotypic Expansions Involving Cdh, Tiana M Scott, Ian M Campbell, Andres Hernandez-Garcia, Seema R Lalani, Pengfei Liu, Chad A Shaw, Jill A Rosenfeld, Daryl A Scott

Duncan NRI Faculty and Staff Publications

Background: Congenital diaphragmatic hernia (CDH) is a life-threatening birth defect that often co-occurs with non-hernia-related anomalies (CDH+). While copy number variant (CNV) analysis is often employed as a diagnostic test for CDH+, clinical exome sequencing (ES) has not been universally adopted.

Methods: We analysed a clinical database of ~12 000 test results to determine the diagnostic yields of ES in CDH+ and to identify new phenotypic expansions.

Results: Among the 76 cases with an indication of CDH+, a molecular diagnosis was made in 28 cases for a diagnostic yield of 37% (28/76). A provisional diagnosis was made in seven other …

Care Ethics, Bruno Latour, And The Anthropocene, Michael Flower, Maurice Hamington

Philosophy Faculty Publications and Presentations

Bruno Latour is one of the founding figures in social network theory and a broadly influential systems thinker. Although his work has always been relational, little scholarship has engaged the relational morality, ontology, and epistemology of feminist care ethics with Latour’s actor–network theory. This article is intended as a translation and a prompt to spur further interactions. Latour’s recent publications, in particular, have focused on the new climate regime of the Anthropocene. Care theorists are just beginning to address posthuman approaches to care. The argument here is that Latourian analysis is helpful for such explorations, given that caring for the …

Analysis Of Generalized Artificial Intelligence Potential Through Reinforcement And Deep Reinforcement Learning Approaches, Jonathan Turner

Theses and Dissertations

Artificial Intelligence is the next competitive domain; the first nation to develop human level artificial intelligence will have an impact similar to the development of the atomic bomb. To maintain the security of the United States and her people, the Department of Defense has funded research into the development of artificial intelligence and its applications. This research uses reinforcement learning and deep reinforcement learning methods as proxies for current and future artificial intelligence agents and to assess potential issues in development. Agent performance were compared across two games and one excursion: Cargo Loading, Tower of Hanoi, and Knapsack Problem, respectively. …

Prognostic And Predictive Biomarkers In Patients With Coronavirus Disease 2019 Treated With Tocilizumab In A Randomized Controlled Trial, Jennifer Tom, Min Bao, Larry Tsai, Aditi Qamra, David Summers, Montserrat Carrasco-Triguero, Jacqueline Mcbride, Carrie M Rosenberger, Celia J F Lin, William Stubbings, Kevin G Blyth, Jordi Carratalà, Bruno François, Thomas Benfield, Derrick Haslem, Paolo Bonfanti, Cor H Van Der Leest, Nidhi Rohatgi, Lothar Wiese, Charles Edouard Luyt, Farrah Kheradmand, Ivan O Rosas, Fang Cai

Faculty, Staff and Students Publications

OBJECTIVES: To explore candidate prognostic and predictive biomarkers identified in retrospective observational studies (interleukin-6, C-reactive protein, lactate dehydrogenase, ferritin, lymphocytes, monocytes, neutrophils, d-dimer, and platelets) in patients with coronavirus disease 2019 pneumonia after treatment with tocilizumab, an anti-interleukin-6 receptor antibody, using data from the COVACTA trial in patients hospitalized with severe coronavirus disease 2019 pneumonia.

DESIGN: Exploratory analysis from a multicenter, randomized, double-blind, placebo-controlled, phase 3 trial.

SETTING: Hospitals in North America and Europe.

PATIENTS: Adults hospitalized with severe coronavirus disease 2019 pneumonia receiving standard care.

INTERVENTION: Randomly assigned 2:1 to IV tocilizumab 8 mg/kg or placebo.

MEASUREMENTS AND MAIN …

Evaluation Of Factors Underlying Sex-Based Disparities In Cardiovascular Care In Adults With Self-Reported Premature Atherosclerotic Cardiovascular Disease, Vardhmaan Jain, Mahmoud Al Rifai, Rodman Turpin, Hatice Nur Eken, Ankit Agrawal, Dhruv Mahtta, Zainab Samad, Stephanie Coulter, Fatima Rodriguez, Laura A Petersen, Salim S Virani

Faculty, Staff and Students Publications

IMPORTANCE: There are limited data regarding sex-based differences in physical and mental health domains and health care access in adults with premature atherosclerotic cardiovascular disease (ASCVD).

OBJECTIVE: To study the association of sex with physical and mental health domains as well as health care access-related factors among adults with self-reported premature ASCVD.

DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort analysis of 748 090 adults aged 18 to 55 years in the Behavioral Risk Factor Surveillance System 2016 to 2019 in the US. Data were analyzed from June to July 2021.

EXPOSURES: Self-reported ASCVD, defined as having a history of coronary artery …

Genetic Subtyping And Phenotypic Characterization Of The Immune Microenvironment And Myc/Bcl2 Double Expression Reveal Heterogeneity In Diffuse Large B-Cell Lymphoma, Zijun Y Xu-Monette, Li Wei, Xiaosheng Fang, Qingyan Au, Harry Nunns, Máté Nagy, Alexandar Tzankov, Feng Zhu, Carlo Visco, Govind Bhagat, Karen Dybkaer, April Chiu, Wayne Tam, Youli Zu, Eric D Hsi, Fredrick B Hagemeister, Xiaoping Sun, Xin Han, Heounjeong Go, Maurilio Ponzoni, Andrés J M Ferreri, Michael B Møller, Benjamin M Parsons, J Han Van Krieken, Miguel A Piris, Jane N Winter, Yong Li, Bing Xu, Maher Albitar, Hua You, Ken H Young

Faculty, Staff and Students Publications

PURPOSE: Diffuse large B-cell lymphoma (DLBCL) is molecularly and clinically heterogeneous, and can be subtyped according to genetic alterations, cell-of-origin, or microenvironmental signatures using high-throughput genomic data at the DNA or RNA level. Although high-throughput proteomic profiling has not been available for DLBCL subtyping, MYC/BCL2 protein double expression (DE) is an established prognostic biomarker in DLBCL. The purpose of this study is to reveal the relative prognostic roles of DLBCL genetic, phenotypic, and microenvironmental biomarkers.

EXPERIMENTAL DESIGN: We performed targeted next-generation sequencing; IHC for MYC, BCL2, and FN1; and fluorescent multiplex IHC for microenvironmental markers in a large cohort of …

P16 Represses Dna Damage Repair Via A /Novel Ubiquitin-Dependent Signaling Cascade, David P Molkentine, Jessica M Molkentine, Kathleen A Bridges, David R Valdecanas, Annika Dhawan, Reshub Bahri, Andrew J Hefner, Manish Kumar, Liangpeng Yang, Mohamed Abdelhakiem, Phillip M Pifer, Vlad Sandulache, Aakash Sheth, Beth M Beadle, Howard D Thames, Kathryn A Mason, Curtis R Pickering, Raymond E Meyn, Heath D Skinner

Faculty, Staff and Students Publications

Squamous cell carcinoma driven by human papillomavirus (HPV) is more sensitive to DNA-damaging therapies than its HPV-negative counterpart. Here, we show that p16, the clinically used surrogate for HPV positivity, renders cells more sensitive to radiotherapy via a ubiquitin-dependent signaling pathway, linking high levels of this protein to increased activity of the transcription factor SP1, increased HUWE1 transcription, and degradation of ubiquitin-specific protease 7 (USP7) and TRIP12. Activation of this pathway in HPV-positive disease led to decreased homologous recombination and improved response to radiotherapy, a phenomenon that can be recapitulated in HPV-negative disease using USP7 inhibitors in clinical development. This …

Identifying Causative Microorganisms In Left Ventricular Assist Device Infections As A Guide For Developing Bacteriophage Therapy, Ishan Kamat, Harveen Lamba, Casey Hines-Munson, Samuel Hudson, Kenneth Liao, Kenneth L Muldrew, Sabrina Green, Austen Terwilliger, Heidi B Kaplan, Robert F Ramig, Anthony Maresso, Barbara W Trautner

Faculty, Staff and Students Publications

BACKGROUND: As more left ventricular-assist devices (LVADs) are implanted, multidrug-resistant LVAD infections are becoming increasingly common, partly due to bacterial biofilm production. To aid in developing bacteriophage therapy for LVAD infections, we have identified the most common bacterial pathogens that cause LVAD driveline infections (DLIs) in our heart transplant referral center.

MATERIALS AND METHODS: We studied a retrospective cohort of patients who received LVADs from November 2003 to August 2017 to identify the common causative organisms of LVAD infection. We also studied a prospective cohort of patients diagnosed with DLIs from October 2018 to May 2019 to collect bacterial strains …

Clinical Opinion: The Diagnosis And Management Of Suspected Fetal Growth Restriction: An Evidence-Based Approach, Christoph C Lees, Roberto Romero, Tamara Stampalija, Andrea Dall'asta, Greggory A Devore, Federico Prefumo, Tiziana Frusca, Gerard H A Visser, John C Hobbins, Ahmet A Baschat, Caterina M Bilardo, Henry L Galan, Stuart Campbell, Dev Maulik, Francesc Figueras, Wesley Lee, Julia Unterscheider, Herbert Valensise, Fabricio Da Silva Costa, Laurent J Salomon, Liona C Poon, Enrico Ferrazzi, Giancarlo Mari, Giuseppe Rizzo, John C Kingdom, Torvid Kiserud, Kurt Hecher

Faculty, Staff and Students Publications

This study reviewed the literature about the diagnosis, antepartum surveillance, and time of delivery of fetuses suspected to be small for gestational age or growth restricted. Several guidelines have been issued by major professional organizations, including the International Society of Ultrasound in Obstetrics and Gynecology and the Society for Maternal-Fetal Medicine. The differences in recommendations, in particular about Doppler velocimetry of the ductus venosus and middle cerebral artery, have created confusion among clinicians, and this review has intended to clarify and highlight the available evidence that is pertinent to clinical management. A fetus who is small for gestational age is …

Isoform-Specific Functions Of Pparγ In Gene Regulation And Metabolism, Wenxiang Hu, Chunjie Jiang, Mindy Kim, Yang Xiao, Hannah J Richter, Dongyin Guan, Kun Zhu, Brianna M Krusen, Arielle N Roberts, Jessica Miller, David J Steger, Mitchell A Lazar

Faculty, Staff and Students Publications

Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor that is a vital regulator of adipogenesis, insulin sensitivity, and lipid metabolism. Activation of PPARγ by antidiabetic thiazolidinediones (TZD) reverses insulin resistance but also leads to weight gain that limits the use of these drugs. There are two main PPARγ isoforms, but the specific functions of each are not established. Here we generated mouse lines in which endogenous PPARγ1 and PPARγ2 were epitope-tagged to interrogate isoform-specific genomic binding, and mice deficient in either PPARγ1 or PPARγ2 to assess isoform-specific gene regulation. Strikingly, although PPARγ1 and PPARγ2 contain identical DNA binding domains, …

In Silico Analysis Of Dnd1 And Its Co-Expressed Genes In Human Cancers, Yun Zhang, Yafang Li, Dhruv Chachad, Bin Liu, Jyotsna D Godavarthi, Abie Williams-Villalobo, Latifat Lasisi, Shunbin Xiong, Angabin Matin

Faculty, Staff and Students Publications

Dead-End (DND1) is an RNA-binding protein involved in translational regulation. Defects in DND1 gene causes germ cell tumors and sterility in rodents. Experimental studies with human somatic cancer cells indicate that DND1 has anti-proliferative and pro-apoptotic function in some while oncogenic function in other cells. We examined The Cancer Genome Atlas data for gene alterations and gene expression changes in DND1 in a variety of human cancers. We found that DND1 is amplified, deleted or mutated in multiple human cancers. In different cancers, DND1 alteration correlates with increased diagnosis age of patients, shift in tumor spectrum or change of tumor …

Global Sporadic-E Climatological Analysis Using Gps Radio Occultation And Ionosonde Data, Travis J. Hodos

Theses and Dissertations

A climatology of sporadic-E (Es) derived from a combined data set of GPS radio occultation (GPS-RO) and ground-based ionosonde soundings is presented for the period from September 2006 to February 2019. The ionosonde soundings were measured using the Lowell Digisonde International (LDI) Global Ionosphere Radio Observatory (GIRO) network consisting of 65 sites and 13,141,060 total soundings. The GPS-RO observations were taken aboard the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites and processed using two binary Es detection algorithms, totaling 9,072,922 occultations. The first algorithm is an S4 amplitude threshold calibrated to the occurrence of any blanketing Es …

Analysis Of Microscopic Carbon Fiber Fragments, Zachary R. Scott

Theses and Dissertations

Carbon Fiber (CF) has different tensile strengths and transverse moduli depending on how they are fabricated. Some CF is export controlled as it can be used for weapons, spacecraft, or gas centrifuges for enriching nuclear fuel. This research project explored a new way to prepare micron sized single CF threads to measure their transverse modulus and compare the moduli of non-export controlled CF to that of an export controlled CF. Five total polyacrylonitrile (PAN) fibers were used in this project, one of which was an export controlled fiber.

Does Restoration Of Urban Riparian Zones Impact Stream Water Quality In Portland, Oregon, Ash Ivanov

University Honors Theses

Riparian zones influence urban stream quality through factors such as shading the stream, adding nutrients through leaf litter, stabilizing the stream banks to reduce turbidity, and filtering toxins out of the water. Riparian restoration often involves changing plant assemblage to be more diverse and include primarily native species instead of non-native, improving connection to the stream through changing stream morphology, improving species habitat, and reducing pollution. The goal of this study was to determine if urban riparian restoration projects in the region were successful, and if not, why that may be the case. The study was performed in the Portland, …

Gender Does Not Equal Genitalia: A Review Of The Implications Of Inclusivity In School-Based Sexual Health Education On The Identity Development Of Non-Binary And Transgender Adolescents, Sol N. Rise

University Honors Theses

Abstinence-only based sexual education has historically been the predominant form of school-based sexuality and sexual health education in the United States since the early 1900s. In recent years, there has been an emergence of more expansive and inclusive comprehensive education, however, both types of sexual education continue to affirm hetero- and cis-centric social and cultural norms around gender and sexual identity that leave transgender and non-binary youth at increased risk of poor psychological well-being and physical health outcomes compared to their peers. There have been considerable recommendations within the discourse community for the linguistic de-gendering of anatomy and anatomical processes, …

Child Success And Parental Marital Status: The Impact Of Mental Health, Poverty, And Trauma, Cambria Ort

University Honors Theses

Children are brought into this world under many different circumstances and to many different families. Some are planned, some are not; all come from families with a range of income, relationship status, and experiences. Throughout a child's life, there can be many changes in the family unit that impact the ways parents are available to care for their children. This includes divorce/separation, incarceration, co-parenting, married life, etc., relationship statuses may change over time. Different life stressors impact the financial wellbeing of a family and parents’ ability to spend time with their children. This study used secondary data analysis of the …

Perversion: A Genealogy Of Deviance And Creation Of The "Other", J D. Lyell

University Honors Theses

Drawing from Thomas Aquinas' Theory of Natural Law, I investigate Euro-Christian conceptions of naturalness and unnaturalness and how they were weaponized to cast racialized groups as perverse in the construction of the United States. I focus on the enforcement of Euro-heteropatriarchy to demonize Indigenous family and gender structures, as well as the characterization of Black bodies as abnormal by white academia to demonstrate some of the ways gender and sexuality have been colonized in the U.S. My research provides a general outline tracing a genealogy of deviance as established by Euro-Christian norms of sexuality and gender, which emerges from a …

A Literary Examination Of The Efficacy Of Zoological Conservation In The United States Versus Foreign Efforts, Madeleine M. Lecorre

University Honors Theses

Falling into the top four threats to biodiversity, human activity is impacting species around the globe like never before. Zoological conservation of threatened species aids in the support and reestablishment of these dwindling populations. The examination of conservation work done in the U.S compared to foreign efforts provides insight into strengths, reveals weaknesses, and will help us better serve threatened species around the world. The status of conservation in the U.S. as well as foreign efforts were assessed through literary review of published reports from accredited organizations. As zoologic conservation aims to conserve threatened species, it is also important to …

Views On Aging – Current Trends And Future Directions For Cross-Cultural Research, Anna E. Kornadt, Clara De Paula Couto, Klaus Rothermund

Online Readings in Psychology and Culture

The investigation of what enables societies and individuals to age well remains one of the greatest challenges of our time. Views on aging are a decisive factor in this process, and thus, improving their understanding through cross-cultural research is of utmost importance. In the current review, we address the role of socio-ecological variables and cultural values and beliefs when investigating country differences in what people think about older persons and getting old themselves. Several complexities are introduced in terms of a differentiated conceptualization of views on aging that takes life domains and normative prescriptions into account, and also in terms …

Effect Of Dicamba On Reproductive Development In Corn And Rice, Mason Castner, Jason K. Norsworthy, L. Tom Barber, Trenton Lee Roberts, Edward E. Gbur

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Research has been published regarding the effects of sublethal dicamba rates applied at different growth stages in soybean [Glycine max (L.) Merr.]; however, there is limited research on the effect of dicamba on reproductive growth in corn (Zea mays L.) and rice (Oryza sativa L.). Experiments were conducted in 2018 and 2019 to determine the potential consequences of dicamba exposure to reproductive stages of corn and rice. Dicamba was applied at 0.56, 5.6, 56, and 560 g ae ha^–1, with a 1X rate being 560 g ae ha^–1. Each rate was applied at …

Soil Organic Carbon And Nutrients Affected By Tree Species And Poultry Litter In A 17-Year Agroforestry Site, Helen C.S. Amorim, Amanda J. Ashworth, Yuri L. Zinn, Thomas J. Sauer

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Tree species and fertilization sources may affect the soil organic carbon (SOC) and fertility in agroforestry (AF) systems in temperate regions, but this remains unexplored. This study assesses the longitudinal trends in the SOC and major nutrients in a 17-year AF site established on an Ultisol in Fayetteville, AR. We evaluated how management and fertilization (mineral vs. organic) affect the soil’s physical and chemical properties using the tree species: red oak (Quercus rubra L.) and pecan Carya illinoinensis (Wangenh.) K. Koch. Long-term applications of poultry litter increased the soil pH, whereas the Mg and S concentrations decreased compared to …

High Resistance To Quinclorac In Multiple-Resistant Echinochloa Colona Associated With Elevated Stress Tolerance Gene Expression And Enriched Xenobiotic Detoxification Pathway, Gulab Rangani, Christopher E. Rouse, Christopher Saski, Rooksana E. Noorai, Vijay Shankar, Amy L. Lawton-Rauh, Isabel S. Werle, Nilda Roma-Burgos

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Echinochloa colona and other species in this genus are a threat to global rice production and food security. Quinclorac, an auxin mimic, is a common herbicide for grass weed control in rice, and Echinochloa spp. have evolved resistance to it. The complete mode of quinclorac action and subsequent evolution of resistance is not fully understood. We analyzed the de novo transcriptome of multiple-herbicide-resistant (ECO-R) and herbicide-susceptible genotypes in response to quinclorac. Several biological processes were constitutively upregulated in ECO-R, including carbon metabolism, photosynthesis, and ureide metabolism, indicating improved metabolic efficiency. The transcriptional change in ECO-R following quinclorac treatment indicates an …

Measurable Microcystin In Ozark Streams Was Rare During Summer 2018 Baseflow Conditions, Bradley J. Austin, Brian E. Haggard

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Accelerated eutrophication due to human activity has been linked to an increase in the occurrence of cyanobacteria in freshwater systems. The purpose of this study was to document the occurrence of microcystin, a common cyanotoxin, within northwest Arkansas streams. Twenty streams were sampled from May through October 2018, and water and periphyton samples were analyzed for microcystin and chlorophyll-a (CHL-a). Mean microcystin concentrations in water samples were low across sites, ranging from < 0.10 to 0.21 μg L⁻¹. Mean microcystin in the periphyton across sites ranged from 2.6 to 9.9 μg m⁻² and were within values observed in the literature. …