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Full-Text Articles in Earth Sciences

Public Horticulture: Process And Design Of The Lincoln Botanical Garden, Brad Kindler May 2024

Public Horticulture: Process And Design Of The Lincoln Botanical Garden, Brad Kindler

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

Beginning in 2012, the local non-profit, The Lincoln Botanical Garden, began organizing the conceptual design and creation of a glass conservatory within a botanical garden in Lincoln, Nebraska. These proposed urban enhancements seek to fill a gap in garden amenities in the city by providing year-round access to public horticulture programming and education.

This project, Public Horticulture: Process and Design of the Lincoln Botanical Garden, documents these efforts and makes design recommendations for a themed Glacial Erratic Garden that could be constructed within the botanical garden.

Advisors: Ellen Paparozzi and Sam Wortman


Understanding The Zonal Variability In Cmip6 Projections Of Sahelian Precipitation, Emmanuel Ogwuche Audu May 2024

Understanding The Zonal Variability In Cmip6 Projections Of Sahelian Precipitation, Emmanuel Ogwuche Audu

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

The uncertainty in model projections of future precipitation across the Sahel has persisted across many generations of Earth System Models (ESMs), with some models predicting drying and others moistening across this region. These discrepancies in future projections pose a challenge for stakeholders and decision makers. Many projections of Sahel precipitation found in the ESMs participating in the sixth phase of Coupled Model Intercomparison Project (CMIP6) show a zonal dipole in precipitation trend, with moistening across the Central and Eastern Sahel and drying projected for the Western Sahel. Previous studies have connected precipitation variability across the Sahel to changes in various …


Polarimetric Radar Signatures In Significant Severe Left-Moving Supercells, Raychel Nelson May 2024

Polarimetric Radar Signatures In Significant Severe Left-Moving Supercells, Raychel Nelson

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

Left-moving (LM) supercells, though rarer than right-moving (RM) supercells, may produce significant severe weather. However, there are very few existing studies on LM supercells, particularly polarimetric radar analyses. The upgrade of the nationwide Weather Surveillance Radar-1988 Doppler (WSR-88D) network to polarimetric capability and subsequent studies vastly improved understanding of RM supercells, but similar efforts have largely not been made for LM supercells. This study employs an automated polarimetric radar signature detection algorithm to examine a dataset of significant severe (hail ≥ 2.00”, wind ≥ 65 kts) LM supercells to quantify their polarimetric signatures. Comparisons are made with RM supercells to …


A Dual-Polarimetric Analysis Of A Large Sample Of Left-Moving Supercells, Ben Schweigert May 2024

A Dual-Polarimetric Analysis Of A Large Sample Of Left-Moving Supercells, Ben Schweigert

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

Supercells have been researched extensively since they were first described over 50 years ago. They are prolific severe weather producers, responsible for the most severe hail, severe wind gusts, and tornadoes. These rotating thunderstorms require attention from forecasters to protect life and property from their threats, most effectively done with Doppler radars. While extensive amounts of radar-based investigations have been completed, they focused almost exclusively on right-moving (RM) supercells, resulting in a knowledge gap surrounding their counter-rotating (left-moving, LM) partners. This study works to fill the void by developing a dataset of LM supercells and analyzing the dual-polarimetric features observed …


A Compilation, Analysis, And Categorization Of 403 Atmospheric And Climate Science Misconceptions, Haeli Leighty May 2024

A Compilation, Analysis, And Categorization Of 403 Atmospheric And Climate Science Misconceptions, Haeli Leighty

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

The National Association of Geoscience Teachers (NAGT) has listed the inaccessibility of research related to misconceptions in atmospheric and climate science as a Geoscience Education Research Grand Challenge (Cervato et al. 2018). This project was a direct response to this call for research and consisted of three distinct steps: 1) data gathering, which included reviewing the literature for relevant misconception data, 2) a qualitative analysis, which included compiling, organizing, and categorizing the data collected, and 3) a quantitative analysis, which included determining the prevalence of each misconception across topic categories, demographic categories, and over time. A total of 403 misconceptions …


The Use Of Laja In Construction In Ancient Mesoamerica: A View From The Southern Gulf Lowlands Of Veracruz, Mexico, Lauren Smith May 2024

The Use Of Laja In Construction In Ancient Mesoamerica: A View From The Southern Gulf Lowlands Of Veracruz, Mexico, Lauren Smith

Honors College Theses

The archaeology of the southern Gulf lowlands of Veracruz, Mexico is notable for its research pertaining to the Olmec culture (Jaime-Riveron 2016; Loughlin 2012; Pool 2006). The region was home to the Colossal Olmec Heads: large, easily identifiable sculptures crafted from the volcanic rock of the Tuxtlas Volcanic Field. The use of volcanic resources in such grand presentations may instill a bias in the research of some archaeologists, but it is important to consider how these and other volcanic resources might have been used in everyday life (e.g., Jaime-Riveron 2016: 86). The consolidated volcanic ash in this region is referred …


Microwave Emission Model Parameter Tuning For Surface Soil Moisture Retrieval Using Uav-Mounted Dual Polarization L-Band Radiometer, Santiago Hoyos Echeverri May 2024

Microwave Emission Model Parameter Tuning For Surface Soil Moisture Retrieval Using Uav-Mounted Dual Polarization L-Band Radiometer, Santiago Hoyos Echeverri

Open Access Theses & Dissertations

Surface soil moisture retrieval from L-band brightness temperature has been developed for the past decades due to multiple beneficial characteristics of 1-2 GHz frequency bands for remote sensing of the environment. Numerous microwave emission models have been proposed for tower and satellite-based operations with successful retrieval of surface soil moisture and vegetation water content. As a result of the development of cost-effective and low-mass microwave L-band radiometers such as the Portable L-band Radiometer (PoLRa), surface soil moisture surveying traditionally developed by satellite missions SMOS and SMAP can now be developed at local scales, bringing these operations to commercial small unmanned …


College Of Natural Sciences Newsletter, Spring 2024, College Of Natural Sciences May 2024

College Of Natural Sciences Newsletter, Spring 2024, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Page 1 Dean's Message
Page 2 New Faculty and New Club on Campus
Page 3 2024 URSCAD Awards
Page 4 Day of Scholars 2024
Page 5 SDSU's First Representation at the Association for Anatomy's 2024
Annual Conference
Page 6-7 2024 Honor's College Convocation
Page 8 Other Student Activities
Page 9 Faculty Awards
Page 10-11 Other News
Page 12 2024 Drone Day and American Association of Geographers Convention - Hawaii
Page 13 55th Annual Geography Convention
Page 14 2024 Stethoscope Ceremony
Page 15 Open PRAIRIE Data



Bay Water Level Influences On Inundation And Morphological Changes Of A Semi-Connected Barrier Island During A Hurricane, Sydney D. Goodman May 2024

Bay Water Level Influences On Inundation And Morphological Changes Of A Semi-Connected Barrier Island During A Hurricane, Sydney D. Goodman

Graduate Theses and Dissertations (2019 - present)

This research aims to identify flooding and erosion changes along a semi-connected barrier island system due to varying bay water levels during storm conditions. The numerical model XBeach is used to simulate Hurricane Michael conditions and the resulting inundation and morphological change near Tyndall Air Force Base (Tyndall AFB). The installation is located 12 miles southeast of Panama City Beach along the panhandle of Florida and is vulnerable to flooding due to its proximity to the Gulf of Mexico (GoM), Saint Andrew Sound and Saint Andrew Bay. A land bridge connects the barrier island to the mainland of Tyndall AFB …


Deterministic Global 3d Fractal Cloud Model For Synthetic Scene Generation, Aaron M. Schinder, Shannon R. Young, Bryan J. Steward, Michael L. Dexter, Andrew Kondrath, Stephen Hinton, Ricardo Davila May 2024

Deterministic Global 3d Fractal Cloud Model For Synthetic Scene Generation, Aaron M. Schinder, Shannon R. Young, Bryan J. Steward, Michael L. Dexter, Andrew Kondrath, Stephen Hinton, Ricardo Davila

Faculty Publications

This paper describes the creation of a fast, deterministic, 3D fractal cloud renderer for the AFIT Sensor and Scene Emulation Tool (ASSET). The renderer generates 3D clouds by ray marching through a volume and sampling the level-set of a fractal function. The fractal function is distorted by a displacement map, which is generated using horizontal wind data from a Global Forecast System (GFS) weather file. The vertical windspeed and relative humidity are used to mask the creation of clouds to match realistic large-scale weather patterns over the Earth. Small-scale detail is provided by the fractal functions which are tuned to …


Learning To Teach About Climate Justice And Social Justice In Science Methods, Mindy J. Chappell Apr 2024

Learning To Teach About Climate Justice And Social Justice In Science Methods, Mindy J. Chappell

Northwest Journal of Teacher Education

In November, the Editors of NWJTE sat down for a conversation with Dr. Mindy J. Chappell, a Science Teacher Educator in the College of Education at Portland State University. Dr. Chappell’s passions include developing teachers who are prepared to disrupt normative science ideologies and provide young people with science instruction that encourages and empowers them to be leaders in their communities. She engages in arts-based educational science research through the methodology of Ethnodance (a term she coined). She places young people and their lived experiences at the heart of her work.


Unearthing The Past: A Comprehensive Study Of Natural And Anthropogenic Changes At An Archaeological Site Through Hydrogeologic Connectivity Utilizing Gis, Mehlich Ii Phosphorus Extractant, And Ph, Dana L. F. Herren Apr 2024

Unearthing The Past: A Comprehensive Study Of Natural And Anthropogenic Changes At An Archaeological Site Through Hydrogeologic Connectivity Utilizing Gis, Mehlich Ii Phosphorus Extractant, And Ph, Dana L. F. Herren

Theses

This thesis aims to thoroughly analyze the Mehlich II Phosphorus Extractant and pH levels at the Bains Gap Village Site in Anniston, AL., while examining the impact of various environmental factors and human activities on them. Phosphorus is often used in archaeology as an indicator of human activity. Soil core samples were collected to analyze anomalies in phosphorus levels.

To establish any relationships, phosphorus and pH levels from soil cores were correlated with findings from past excavation units and features. The potential effects of hydrogeologic connectivity on soil phosphorus and pH levels were investigated. Geospatial technologies were used to manage …


What Soil Is Worth: A Cost-Benefit Framework Analysis Of Syntropic Farming, Aubrey Kettley Apr 2024

What Soil Is Worth: A Cost-Benefit Framework Analysis Of Syntropic Farming, Aubrey Kettley

Independent Study Project (ISP) Collection

Syntropic farming, a type of regenerative agriculture, models its farming system after a forest. This type of farming prioritizes soil health while also providing a varied yield of crops. Because it is a fairly new system globally, little research has been done on the economic impacts of syntropic farming, and therefore the feasibility of scaling up regenerative systems like this. This study aims to analyze the economic feasibility of this system through a literature review and a cost-benefit analysis framework. The results highlight the applicability, environmental advantage and economic feasibility of the system. Based on the presented framework, the short …


Demographic Consequences Of Off-River Nesting For Piping Plover (Charadrius Melodus) And Interior Least Tern (Sternula Antillarum Athalassos) In The Lower Platte River System, Nebraska, Elsa M. Forsberg Apr 2024

Demographic Consequences Of Off-River Nesting For Piping Plover (Charadrius Melodus) And Interior Least Tern (Sternula Antillarum Athalassos) In The Lower Platte River System, Nebraska, Elsa M. Forsberg

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

Piping plovers (Charadrius melodus; hereafter, plovers) and interior least terns (Sternula antillarum athalassos; hereafter, terns) are two avian species that nest along the Lower Platte River system (LPRS) in Nebraska. In the LPRS, river sandbars provide natural nesting habitat, but off-river sites provide substantial nesting habitat especially when sandbar habitat is scarce. Although presumed to be important for the persistence of plovers and terns, off-river habitat is not self-sustaining and predicted to decline. Understanding the vital rates of plovers and terns in the LPRS will inform the role of off- river sites in the future conservation …


How Can Morocco’S Crisis Management And Disaster Response Be Optimized? Lessons From The Al Haouz Earthquake Response, Clara Normand Apr 2024

How Can Morocco’S Crisis Management And Disaster Response Be Optimized? Lessons From The Al Haouz Earthquake Response, Clara Normand

Independent Study Project (ISP) Collection

Morocco’s disaster management strategy has evolved in reaction to historical crises. On September 8th, 2023, the Al Haouz region of Morocco was struck by a 7.2 magnitude earthquake. The area was especially vulnerable to such a disaster due to its underdeveloped infrastructure, remote location, and lack of services. As the last phase of the disaster management cycle is unfolding, seven months after the earthquake, this research assesses the successes and challenges of the response and establishes areas of improvement to implement in national policies to optimize future crisis management across all four stages of the disaster management cycle.


Remote, Rugged Field Scenarios For Archaeology And The Field Sciences: Object Avoidance And 3d Flight Planning With Suas Photogrammetry, Carla Klehm, Malcolm D. Williamson, Leland C. Bement, Brandi Bethke Apr 2024

Remote, Rugged Field Scenarios For Archaeology And The Field Sciences: Object Avoidance And 3d Flight Planning With Suas Photogrammetry, Carla Klehm, Malcolm D. Williamson, Leland C. Bement, Brandi Bethke

Center for Advanced Spatial Technologies Publications and Presentations

Advances built into recent sUASs (drones) offer a compelling possibility for field-based data collection in logistically challenging and GPS-denied environments. sUASs-based photogrammetry generates 3D models of features and landscapes, used extensively in archaeology as well as other field sciences. Until recently, navigation has been limited by the expertise of the pilot, as objects, like trees, and vertical or complex environments, such as cliffs, create significant risks to successful documentation. This article assesses sUASs’ capability for autonomous obstacle avoidance and 3D flight planning using data collection scenarios carried out in Black Mesa, Oklahoma. Imagery processed using commercial software confirmed that the …


International Ocean Drilling Program: Outstanding Talents And Their Scientific Contributions, Tianyue Peng, Wang Ding, Ye Yuan, Benduo Zhu, Bing Han Feb 2024

International Ocean Drilling Program: Outstanding Talents And Their Scientific Contributions, Tianyue Peng, Wang Ding, Ye Yuan, Benduo Zhu, Bing Han

Bulletin of Chinese Academy of Sciences (Chinese Version)

The International Ocean Discovery Program (IODP) is one of the most successful international scientific collaboration in the field of Earth sciences. The program began in 1968 and has been ongoing for over 57 years, continuing to develop and thrive. The IODP has made numerous breakthroughs in areas such as plate tectonics, climate change, deep-sea resources, disaster prevention and mitigation, and deep-sea drilling technology, greatly advancing the progress of Earth sciences and benefiting human society. Throughout its development, the IODP has also nurtured a large number of scientific talents, with 45 scientists receiving a total of 68 globally influential awards, some …


College Of Natural Sciences 2023 Year-End Publication, College Of Natural Sciences Feb 2024

College Of Natural Sciences 2023 Year-End Publication, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Page 1 Dean's Message
Page 3 Department Highlights
Page 4 One Day for State
Page 5 Noble Prize Winner Speaks on Campus
Page 6-7 Faculty Excellence
Page 8-9 Student Excellence
Page 10 Outreach Program
Page 10 Events and Traditions
Page 11 Connections Abroad
Page 12 Student Spotlight
Page 13 Alumni Spotlight
Page 14 First Ever Drone Day
Page 15 Grand Opening of POET Bioproducts Center
Page 16 Work Anniversaries


Towards Sociobiogeochemistry: Critical Perspectives On Anthropogenic Alterations To Soil Nitrogen Chemistry Via U.S. Urban And Suburban Development, Christopher D. Ryan Feb 2024

Towards Sociobiogeochemistry: Critical Perspectives On Anthropogenic Alterations To Soil Nitrogen Chemistry Via U.S. Urban And Suburban Development, Christopher D. Ryan

Dissertations, Theses, and Capstone Projects

The ecological impacts of changes to land use are relevant to concerns about climate change, eutrophication of waterbodies, and reductions in biodiversity. As a foundational component of ecosystem functioning, changes to soil biogeochemistry have significant effects on overall ecosystem health. With cities continuing to grow and develop in extent, the impacts of urbanization and suburbanization on soils are of particular concern. Despite a wide range of natural climatic and geologic conditions, several factors have driven similar patterns of land transformation and management across the United States. In particular, federal initiatives including the Home Owners Loan Corporation, the Federal Housing Administration, …


Inventory Of Western United States Glaciers- 2020, Shrinidhi Ambinakudige, Bernard Abubakari Jan 2024

Inventory Of Western United States Glaciers- 2020, Shrinidhi Ambinakudige, Bernard Abubakari

CAS Publications

The dataset employed for delineating glacier boundaries in the Western United States comprises a compilation of original Sentinel-2 images obtained from the European Space Agency's Copernicus website. These images were instrumental in generating the glacier inventory. Additionally, the dataset includes a Python and R script specifically crafted for processing and classifying Sentinel images. The outcome of this process is represented in an ESRI shapefile, which contains an inventory of glaciers extracted from Sentinel images.


Spatial Analyses On Pre-Earthquake Ionospheric Anomalies And Magnetic Storms Observed By China Seismo-Electromagnetic Satellite In August 2018, Jann-Yeng Tiger Liu, Xuhui Shen, Fu-Yuan Chang, Yuh-Ing Chen, Yang-Yi Sun, Chieh‑Hung Chen, Sergey Pulinets, Katsumi Hattori, Dimitar Ouzounov, Valerio Tramutoli, Michel Parrot, Wei-Sheng Chen, Cheng-Yan Liu, Fei Zhang, Dapeng Liu, Xue-Min Zhang, Rui Yan, Qiao Wang Jan 2024

Spatial Analyses On Pre-Earthquake Ionospheric Anomalies And Magnetic Storms Observed By China Seismo-Electromagnetic Satellite In August 2018, Jann-Yeng Tiger Liu, Xuhui Shen, Fu-Yuan Chang, Yuh-Ing Chen, Yang-Yi Sun, Chieh‑Hung Chen, Sergey Pulinets, Katsumi Hattori, Dimitar Ouzounov, Valerio Tramutoli, Michel Parrot, Wei-Sheng Chen, Cheng-Yan Liu, Fei Zhang, Dapeng Liu, Xue-Min Zhang, Rui Yan, Qiao Wang

Mathematics, Physics, and Computer Science Faculty Articles and Research

The China Seismo-Electromagnetic Satellite (CSES), with a sun-synchronous orbit at 507 km altitude, was launched on 2 February 2018 to investigate pre-earthquake ionospheric anomalies (PEIAs) and ionospheric space weather. The CSES probes manifest longitudinal features of four-peak plasma density and three plasma depletions in the equatorial/low-latitudes as well as mid-latitude troughs. CSES plasma and the total electron content (TEC) of the global ionosphere map (GIM) are used to study PEIAs associated with a destructive M7.0 earthquake and its followed M6.5 and M6.3/M6.9 earthquakes in Lombok, Indonesia, on 5, 17, and 19 August 2018, respectively, as well as to examine ionospheric …


Why Is Grant Lake A Reservoir? A Brief Geological And Human History, From The Pleistocene To The Present, Robert B. Marks Jan 2024

Why Is Grant Lake A Reservoir? A Brief Geological And Human History, From The Pleistocene To The Present, Robert B. Marks

Eastern Sierra History Journal

Drawing on a range of archival resources and illustrative material, Prof. Marks probes why and how Grant Lake in the Eastern Sierra of California became a reservoir. The process is long and involved, and has much to do with a remote and ancient lake ultimately being developed to serve the water needs of the distant city of Los Angeles.


Critical Convergence: Mapping The Boundaries Of How Faculty Interrogate Whiteness In The Geoscience Educational Landscape, James E. Hobbs Jan 2024

Critical Convergence: Mapping The Boundaries Of How Faculty Interrogate Whiteness In The Geoscience Educational Landscape, James E. Hobbs

Educational Leadership & Policy Studies Dissertations - Archive

This study examined the role of faculty members in interrogating whiteness within geoscience education. The dominant reliance on whiteness as the primary way of knowing in geoscience education has long perpetuated a singular perspective that serves as a mechanism for reinforcing existing power structures rooted in white supremacy. Drawing on tenets from Critical whiteness Studies, Curriculum Theory, and Transformative Learning Theory, this research investigated U.S. higher education faculty members' strategies and challenges in disrupting whiteness within the geoscience curriculum.

Through critical qualitative narrative inquiry, data were collected through semi-structured interviews with geoscience faculty members across multiple institutions across the United …


Probable Extirpation Of The Jackrabbit (Lepus Californicus) From Arkansas, D.B. Sasse Jan 2024

Probable Extirpation Of The Jackrabbit (Lepus Californicus) From Arkansas, D.B. Sasse

Journal of the Arkansas Academy of Science

The black-tailed jackrabbit (Lepus californicus) was first documented in Arkansas during the modern era in Franklin County in 1927. Over the next few decades records were reported from multiple counties in northwest Arkansas and the species was locally common in Benton, Crawford, and Washington counties in the 1950s. The last Arkansas record documented in the scientific literature was from 1968 and since then there have only been three credible reports, with the last being from the late 1980s. The Arkansas Game and Fish Commission solicited reports of jackrabbits from the public and failed to find evidence of them from a …


Ultrastructure Of The Biflagellated Spermatozoon In The Western Siren, Siren Nettingi (Caudata: Sirenidae), Using Scanning Electron Microscopy, S.E. Trauth Jan 2024

Ultrastructure Of The Biflagellated Spermatozoon In The Western Siren, Siren Nettingi (Caudata: Sirenidae), Using Scanning Electron Microscopy, S.E. Trauth

Journal of the Arkansas Academy of Science

I investigated the ultrastructure of the biflagellated spermatozoon of the Western Siren, Siren nettingi, using scanning electron microscopy from salamanders collected in northeastern Arkansas. My primary goal in this study was to reveal the general morphology of the distinctive sperm cell components (two axonemes, two undulating membranes, and two axial fibers), which run nearly the entire length of the spermatozoon. These remarkable gamete structures are found in members of the salamander family Sirenidae and do not conform to spermatozoal ultrastructure of any other salamander species. Moreover, the biflagellated sperm are the end product of an extraordinary assemblage of complex maturation …


History And Distribution Of The Wood Stork (Mycteria Americana) In Arkansas, R. Tumlison, L. Serviss Jan 2024

History And Distribution Of The Wood Stork (Mycteria Americana) In Arkansas, R. Tumlison, L. Serviss

Journal of the Arkansas Academy of Science

Wood Storks (Mycteria americana) were thought to be common visitors to Arkansas in the early 1900s, but observations declined mid-century. Surveys of citizen science data and other online sources indicate that numbers of unique observations and total counts of birds have increased since 2000. Storks do not breed here, but have been reported in 34 of 75 counties, and appear mostly in August and September. Birds apparently originate from Mexico. Number of observations have increased since 2016, but many of those observations include only a few birds rather than larger flocks.


An Annotated Checklist Of The Camel Crickets (Insecta: Orthoptera: Rhaphidophoridae) Of Arkansas, H.W. Robison, C.T. Mcallister Jan 2024

An Annotated Checklist Of The Camel Crickets (Insecta: Orthoptera: Rhaphidophoridae) Of Arkansas, H.W. Robison, C.T. Mcallister

Journal of the Arkansas Academy of Science

A total of 14 native species of camel crickets and one introduced taxon representing three genera (Ceuthophilus, Phrixocnemis, and Diestrammena) of the orthopteran family Rhaphidophoridae, are herein reported from Arkansas. The most diverse genus was Ceuthophilus, with 13 native species, while Phrixocnemis had one native species, and Diestrammena, formerly Tachycines, was represented by one introduced species. This updated checklist is intended to be of use to entomologists, naturalists, professional biologists, and resource managers in evaluating the biodiversity of Arkansas. State distributional maps are provided for each species listed by county, and habitats are discussed in which each species was taken …


Fish Leeches Of Arkansas, D.J. Richardson, W.E. Moser, C.T. Mcallister, S.P. Lawson, H.W. Robison Jan 2024

Fish Leeches Of Arkansas, D.J. Richardson, W.E. Moser, C.T. Mcallister, S.P. Lawson, H.W. Robison

Journal of the Arkansas Academy of Science

Recent collection within Arkansas greatly enlarges the knowledge concerning hosts and distributions of fish leeches within the state. The natural history of the 6 species of fish leeches known from Arkansas (Placobdella montifera, Placobdella pediculata, Cystobranchus klemmi, Cystobranchus verrilli, Myzobdella lugubris, and Myzobdella reducta) is reviewed and updated and molecular data are provided.


Post-Glacial Landscape Evolution Of The Lower St. Croix River Valley: The Enigma Of Glacial Lake Grantsburg, The Osceola Bench, And The St. Croix Dells, Hunter Delikowski Jan 2024

Post-Glacial Landscape Evolution Of The Lower St. Croix River Valley: The Enigma Of Glacial Lake Grantsburg, The Osceola Bench, And The St. Croix Dells, Hunter Delikowski

All Graduate Theses, Dissertations, and Other Capstone Projects

The St. Croix River valley (SCRV) is the product of dyssynchronous glacial advance and retreat of several glacial lobes during regional deglaciation of the Late Pleistocene-Early Holocene transition. Additionally, the SCRV has been dramatically shaped by multiple proglacial lake drainage episodes. Therefore, the SCRV is an important case study to understanding the impacts of proglacial lake spillover processes. However, the magnitude, frequency, timing, duration, and geomorphic impacts of these floods remain enigmatic. We focus on a specific reach of the SCRV, which we name the Lower SCRV for the purpose of this study. The lower SCRV contains several anomalous landforms …


Pleated Plasma Membrane Complex In Spermatids Of The Western Siren, Siren Nettingi (Caudata: Sirenidae), S.E. Trauth Jan 2024

Pleated Plasma Membrane Complex In Spermatids Of The Western Siren, Siren Nettingi (Caudata: Sirenidae), S.E. Trauth

Journal of the Arkansas Academy of Science

I investigated the pleated plasma membrane complex of linear folds and biflagellar entities in developing spermatids of the Western Siren, Siren nettingi. My primary goal was to reveal the ultrastructural morphology of these distinctive cellular folds (usually 8 in number) as they support the flagellar formation of biflagellated sperm found in this salamander and in other members in the family Sirenidae. My results reveal that the biflagellar components (2 sets of axonemes, undulating membranes, and axial fibers), termed biflagellar complex, develop between folds or are attached onto these folds. The folds themselves are transitory and do not directly contribute to …