Digital Commons Network^™

Ediacaran Paleocommunity Structure, Body Size Evolution, And The Rise Of Complex Animals, Matthew Philip Craffey

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The Ediacaran period (635-538ma) is a key interval in the evolution of life as it records the first macroscopic animal communities. Major extinction pulses appear to have altered the composition of the global marine biosphere between each sub-interval of the Ediacaran Period: the Avalon, White Sea, and Nama assemblage Zones. While considerable attention has been paid to the causes of these extinction pulses, less has been afforded to the consequences of Ediacaran biotic turnover for community organization and function. Moreover, it is unclear how body size - the defining trait of macrofauna - affected the transition between animal groups across …

Maggot Mass Effect On The Development And Survival Of Forensic Blow Flies, Akomavo Fabrice Gbenonsi

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

Forensic entomology scientists use blow flies' developing patterns to estimate the postmortem interval (PMI). However, larval aggregations produce metabolic heat, resulting in complex microclimates that may change growth timetables. This study investigates how larval density and associated temperature changes affect the development and survival of two forensically essential blow fly species, Lucilia sericata and Calliphora vicina.

This study examined how larval density and associated thermal profiles affect the development of both blow fly species. Using a split-plot design, we tested four larval densities at 25°C and 30°C, with temperature gradients measured via thermocouple at four mass positions three times …

Assessment Of Sampling Gears For Bigheaded Carp In Mid-Order Prairie Rivers In Nebraska, Brett M. Anderson

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

Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis (collectively bigheaded carp) have invaded tributaries to the Missouri River and Platte River in Nebraska, USA. Information pertaining to efficient sampling protocols for assessing bigheaded carp populations as well as benefiting removal efforts is needed. Herding is a method used to increase the capture efficiency and detection probability of adult bigheaded carp by simultaneously using active and passive sampling gears. During June-July 2023, four herding techniques were assessed regarding their ability to elicit directional movement past an enclosure gate. The combination of sound and electrofishing resulted in the highest mean …

Radar Precursors To Severe Weather Reports In Left-Moving Supercells, Eric A. Carothers

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

While much research has examined dual-polarimetric signatures of right-moving supercells, very little has been done with left-moving supercells. Given that left-moving supercells are thought to be disproportionate producers of large hail, understanding their internal dynamics is vitally important. This study examines differences and trends in the dual-polarimetric signatures of left-moving supercells to identify precursors to severe weather reports. A dataset of left-moving supercells associated with severe weather reports was created. These storms are processed with an automated analysis algorithm that identifies and quantifies the polarimetric signatures in each storm. A method for analysis of differences and trends in their dual-polarization …

From Land To Lagoon: The Spatiotemporal Biogeochemical Dynamics Of Arctic Coastal Erosion In Elson Lagoon, Alaska, Sasha Victoria Peterson

Open Access Theses & Dissertations

TThe Arctic is warming rapidly, driving widespread environmental change across coastal landscapes, including permafrost thaw, shoreline erosion, and shifts in sediment and carbon dynamics, pose growing challenges for predicting carbon cycling and climate feedbacks. This dissertation investigates the spatiotemporal variability of erosion, decomposition, and nearshore turbidity in Elson Lagoon, Alaska (1955–2023), to better understand how carbon, nitrogen, and sediment are mobilized, transformed, and potentially emitted as greenhouse gases in Arctic coastal systems. Chapter 2 presents a high-resolution analysis of shoreline change and erosion-driven material fluxes spanning nearly seven decades. Drawing on 795 soil data points, airborne LiDAR, and five shoreline …

The Effect Of Hiv-1 Infection Associated Bacterial Lipopolysaccharide (Lps) On Human Oral Keratinocytes: Implications For Promoting Chronic Inflammation, Md Shafayat Jamil

Theses and Dissertations

Human immunodeficiency virus type 1 (HIV-1) remains a major global health concern, affecting approximately 39 million people worldwide, with 500,000 new infections reported in 2022. While combined antiretroviral therapy (cART) has significantly reduced viral replication, HIV-1 infection is linked to various comorbidities, including oral dysbiosis and accelerated aging. Immune dysregulation in HIV-1–infected individuals promotes the proliferation of pathogenic gram-negative bacteria like Porphyromonas gingivalis, a key contributor to periodontal disease. P. gingivalis secretes lipopolysaccharide (LPS), which adversely affects human oral keratinocytes (HOK), the first line of defense against microbial threats in the oral cavity. HOK recognize LPS as a threat, …

Spatio-Temporal Pattern Of Nutrient Dynamics In The South Texas Coastal Watershed, Mohammad Sadman Alam

Theses and Dissertations

Eutrophication threatens aquatic ecosystems by altering productivity through excessive nutrient inputs. In some systems, primary productivity is limited by nitrogen (N), phosphorus (P), or both, based on the N:P ratio defined by the "Redfield" ratio. South Texas, facing rapid urban growth and industrialization, is at risk of higher nutrient loads, but research on nutrient dynamics in this region is limited. This study investigates nutrient variations in the freshwater (FW) abandoned distributaries of the Rio Grande and hypersaline saltwater (SW) systems. Results showed a significant decrease in dissolved inorganic nitrogen (DIN) and an increase in dissolved inorganic phosphorus (DIP), shifting the …

Inferring Feeding Biology In Extinct Shrews (Soricidae: Mammalia): Application Of A Linear Morphometric Approach, Derek J. Den Ouden

Electronic Theses and Dissertations

Linear morphometrics have been used extensively to infer the ecology of fossil organisms, but shrews have not yet been thoroughly explored using this technique. Often considered to have a homogenous insectivorous diet, direct dietary observation suggests shrew dietary diversity is substantial. Diversity of this nature is well established to have influenced skull morphology in other mammal clades, so similar patterns are hypothesized to be detectable in shrews. To test this, I examined the link between known diet and morphological disparity in extant shrews using linear morphometrics and then utilized that framework to infer the dietary ecology of several fossil taxa. …

Effects Of Environmentally Relevant Concentrations Of Roundup On Oxidative-Nitrative Stress, Cellular Apoptosis, Prooxidant-Antioxidant Homeostasis, Renin And Cyp1a Expressions In Goldfish: Molecular Mechanisms Underlying Kidney Damage During Roundup Exposure, Md Imran Noor, Md Saydur Rahman

School of Earth, Environmental, & Marine Sciences Faculty Publications

Roundup is one of the most widely used glyphosate-based harmful herbicides in the United States as well as globally, which poses a severe risk for terrestrial and aquatic organisms. In order to identify the detrimental effects of Roundup exposure in aquatic organisms, we investigated the environmentally relevant concentrations of Roundup exposure (low dose: 0.5 μg/L and high dose: 5.0 μg/L for 2 weeks) on renin expression, oxidative-nitrative stress biomarkers (e.g., 2,4-dinitrophenol, DNP; and 3-nitrotyrosine protein, NTP), prooxidant-antioxidant enzymes expressions (e.g., superoxide dismutase, SOD; and catalase, CAT), cellular apoptosis, and cytochrome P450 1A (CYP1A) mRNA levels in the kidneys of goldfish …

Microplastics In Coastal And Marine Environments: A Critical Issue Of Plastic Pollution On Marine Organisms, Seafood Contaminations, And Human Health Implications, Rebecca Muñiz, Md. Saydur Rahman

School of Earth, Environmental, & Marine Sciences Faculty Publications

Plastic has quickly become one of the world's most prevalent environmental pollutants. Population growth has only amplified the demand, resulting in 430 million tons of plastic produced annually, with 11 million tons ending up in our oceans. Without intentional intervention, plastic waste in the oceans is expected to triple, posing severe risks for the aquatic ecosystems, animals, and humans dependent on these waters. As plastic accumulates in oceans and other water environments, the non-biodegradable particles break down into micro- and nano-plastics, invading coastal and marine organisms and causing considerable physiological and morphological damage. This is especially concerning for the millions …

Conservation Agriculture Practice Effects On Greenhouse Gas Emissions From Fine-Textured Soils In Arkansas, Lauren Gwaltney

Graduate Theses and Dissertations

Biochar application and reduced tillage (RT) are both practices within the conservation agriculture framework, but specific impacts of these practices on direct greenhouse gas (GHG) emissions still require investigation in varied agricultural systems. This research aimed to evaluate the effects of biochar source (i.e., powder- and pellet-sized) and application rate (i.e., 0, 2.5, and 5 Mg ha^-1) on GHG production in simulated furrow-irrigated rice (Oryza sativa) in a greenhouse experiment, and to evaluate the effects of RT relative to conventional tillage (CT) on GHG production in soybean (Glycine max) in southeast Arkansas. Both studies …

Reevaluating The Drumian Carbon Isotope Excursion (Dice) In Western-Central Utah, Michelle M. Norman

Undergraduate Honors Capstone Projects

The Drumian Stage of the Cambrian Period is defined by the First Appearance Datum (FAD) of the cosmopolitan trilobite Ptychagnostus atavus in 504.5 Ma strata deposited on the slope and shelf of the Laurentia margin. The Drumian Global Stratotype Section and Point (GSSP), showing the best preserved example of P. atavus compared to global outcrops, is defined in the Drum Mountains of west-central Utah. Due to the inconsistent nature of fossil preservation, researchers have sought secondary proxies to identify Drumian-aged strata in the absence of age-diagnostic fauna. One key proxy is the Drumian Carbon Isotope Excursion (DICE), an ~-2.5‰ carbon …

Cranial Ontogeny Of The Extinct Dwarf Tapir Tapirus Polkensis; With Comparison To That Of The Extant Tapirus Bairdii (Tapiridae, Perissodactyla), Johannah Orendorff

Electronic Theses and Dissertations

Tapirus polkensis is the smallest known species of tapir to ever live, and the largest deposit of their fossils is currently located at the GFS in Gray, TN. Phylogenetics suggest that the extant T. bairdii may be the sister taxon to T. polkensis, although they differ greatly in their morphology. Variation exists among adult T. polkensis specimens, with patterns not present in T. bairdii. For this study, as series of 2D GMAs, with TPSs, were rendered on 10 skulls of T. polkensis and 48 skulls of T. bairdii, across both species’ ontogenetic series. Analyses confirmed that growth …

A System And Method For Measuring Spatially Varying Surface Appearances With A Study Of Feathers, Jessica Baron-Lis

All Dissertations

Real-world materials, particularly biological structures such as feathers exhibit complex appearances that vary spatially across their surfaces. The field of computer graphics provides a means of understanding such surfaces through material modeling which uses both analytical models and data acquired from light-surface interactions. There are many efforts within the past decade in measuring materials for graphics, but common limitations in these works include not accounting for spatially varying properties and reliance on neural networks and synthetic datasets.

Feathers from modern birds present diverse appearances due to how light interacts with their unique hierarchical microstructures. Variations in those structures lead to …

The Effects Of Climate Change On The Advancement Of West Nile Virus, Mackenzie R. Epperson

ATU Scholars Symposium

The West Nile virus (WNV) first emerged in the United States in the year 1999 within the state of New York and has become endemic throughout the country over time. This virus is contracted from an avian species acting as the reservoir host, by the vector species which are mosquitoes. From this point, the mosquitoes transmit the virus to humans and other mammals, which are the dead end hosts. The WNV often presents itself as flu-like symptoms, but in serious cases can cause severe arboviral neurological disease. Since this is an arbovirus, it is important to have the ability to …

From The Ground Up: Community-Based Participatory Research Reclaiming The Science Of Lead, Juan Manuel Rubio, Bavisha Kaylan, Anthony Diaz, Patricia Flores, Maya Cheav, David C. Bañuelas, Ashley Green, Annika Hjelmstad, Ariane Jong-Levinger, Tim Schütz, Maya Carrasquillo, Alana M. W. Lebron, Jun Wu

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

For decades, the dominant approach to lead poisoning has been to focus on homes affected by lead paint and to treat children who are already suffering from lead poisoning. This individualizing approach developed in the context of the defunding and deregulation of government agencies in the 1980s. In recent years, however, community–academic partnerships have reframed lead as an environmental issue produced by the development of the lead industry in the twentieth century and connected to overlapping histories of exploitation, discrimination, and inaction. These community-based projects have contributed to shifting research agendas (by emphasizing historical analysis and the study of the …

Quantifying The Rates Of Coastal Change Along Smith Island, Maryland, Sarah Lacy, Ravi Sankar

Longwood Senior Thesis Proposal

As increased climate variability continues to alter the environment, coastal landscapes are becoming increasingly vulnerable to geomorphic change. Coastal erosion, driven by rising sea levels, land subsidence, more intense storm events and human-induced activities poses a serious threat to the sustainability and resilience of island environments like Smith Island, a small marsh island located in the Chesapeake Bay. This study investigates the impacts of recent shoreline change along selected alongshore segments of the island’s coast. Using a combination of aerial imagery, field surveying techniques, and novel geospatial analyses, the project aims to identify areas at highest risk of erosion and …

Trenching And Compost Sustain Grain Yield Increases Over Nine Years On Deep Sands But At A Cost, David J.M. Hall, Tom J. Edwards

Grain and Other Field Crops Research Articles

Context. Crops grown on deep sands on the south coast of WA are limited by soil physical and chemical properties including compaction and poor nutrition. Aims. Crops grown on deep sands on the south coast of Western Australia are limited by soil physical and chemical properties including compaction and poor nutrition. Our aim was to determine what effects deep-placed organic amendments have on soil properties and crop production in a deep sand and whether such amendments are profitable. Methods. A long-term field trial was conducted over nine years (2015–2023) to investigate soil amendments including lime (0 and …

Development Of Isoscapes For Hong Kong Freshwater Streams As A Basis For Ecological Studies, Hon Tim Yip

Lingnan Theses (MPhil & PhD)

Applications of isoscapes in terrestrial and marine ecosystems have grown notably as a tool for studying animal movement. However, isoscapes are rarely used in freshwater ecosystem because current iterations of isoscapes commonly model baseline distributions of bulk stable isotope analysis (SIA) data, which may be inadequate for providing the necessary resolution for fine spatial scale stream environments. This issue could potentially be addressed using compound specific stable isotope analysis, a new method that measures the isotopic composition of individual compounds to provide more comprehensive information than bulk SIA. My study focuses on δ¹³C of essential amino acids (EAA-δ …

The Effect Of Soil Conditioner And Growth Booster On The Agronomic Characters And Number Of Nodules Of Black Soybean, Tien Turmuktini, I Putu Rahmat Santoso, Lia Amalia, Nunung Sondari, Elly Roosma Ria, Yenny Muliani, Endang Kantikowati, Tualar Simarmata

Jurnal Kultivasi

Soil Conditioner & Growth Booster (SCGB) is a potion that was made to be used as a soil conditioner and plant growth promoter. SCGB is made from organic matter, biological fertilizers, soil ameliorants, and microelements. This research aims to determine the best dosage of SCGB on the agronomic characters, effective nodules, and black soybean variety ‘Detam-1’ yield. This research was conducted in the experimental field of the Faculty of Agriculture, Winaya Mukti University, Sumedang, Indonesia. This experiment used a simple randomized block design (RBD) with six treatments (0, 3, 6, 9, 12, 15 kg/ha) and repeated 4 times. The observation …

Grassland For Our World, F Riveros

IGC Proceedings (1977-2023)

The present-day role of grasslands and fodder is reviewed with respect agriculture, animal production and environmental concerns. The world 's grazing lands are a finite resource nnd, overall, are being badly mnnaEed; in most developing countries action is required now, before it is too lnte. They will continue to be a major source of animal feed for the foreseeable future; encroachment from cropping will con

Human Impact On Terrestrial Ecosytems- What We Know And What We Are Doing About It, H A. Mooney

IGC Proceedings (1977-2023)

At present the impact of humankind on the Barth System is substantial mul will become greater as we continue to add over 80 million people to the global population each year. Collectively the human species utilises over a third of the total fresh water that is available, as well as an equivalent amount of tho total terrestrial productivity. Possil energy is being consumed at a prodigious rnte and fuels, among other things, over a half a billion vehicles. To support the large human population the Earth has been greatly reconfigured with much of the land utilised for grazing and agriculture. …

Grasslands For Sustainable Ecosystems, Malcolm Hadley

IGC Proceedings (1977-2023)

Grasslnnds present many advantages for examining issues related to sustainability. Grasslands include planted pastures as well as a variety of natural rangelands in situations ranging from semi-arid to subhumid. Diversity is also reflected in the spectrum of grassland users and uses, for example, nomadic pastoralism, extensive ranches, intensive pastures, wildlife tourism, game hunting. And in terms of sustainability of resource management, grasslands encompass a wide range of contrasting situations and conflicts in resource use. Heavy grazing pressure associated with increasing human populations in certain tropical savannas, the implications of rural depopulation to traditional pasture management in alpine regions, and the …

Red Clover Hybrid Ryegrass Associations Results Obtained From 1984 To 1987 In Four French Regions, C Pfitzenmeyer, C Longueval

IGC Proceedings (1977-2023)

In France, red clover is often grown in association with a grass in order, if not to increase the yield of forage, at least to improve its quality by having a larger protein content in the harvested product. Among the grass species associated to red clover, Italian ryegrass, too aggressive a competitor, is replaced more and more by hybrid ryegrass. The aims of the present work were the following

1% to obtain quantitative references on the behaviour o[ hybrid ryegrass/red clover associations in four contrasting regions of France ;

2% to check that the presence of clover, through the transfer …

Potentials Of Summer Fodders Under Intensive Cropping System In India, M S. Tiwana, Thakur Singh

IGC Proceedings (1977-2023)

One of the reasons for low milk production in India is the non-availability of good quality fodders in sufficient quantity. Therefore, it is necessary to bridge the gap of this acute short­age of fodder for increasing the milk production. There seems to be no possibility of increasing area under fodders and the only alternative looks to be the ulilization of vacant land (70 days) after harvesting wheat and before the sowing of main summer season crops. However, the growing of these crops may have some effect on the yield of succeeding crops by depleting or replenishing the nutrient status of …

Competitive Effects On Production Of Lolium Perenne L. And Trifolium Alexandrinum L. In Mixture And Mono-Culture, M S. Tiwana, K P. Puri, I S. Thind

IGC Proceedings (1977-2023)

Berscem (Trifolium alexandrinum L.) is grown as a fodder crop by every farmer of north India. Though it is a very good multi-cul legume fodder, yet its dry matter percentage is low which indirectly affects the total dry matter production over a period of 6 to 7 months. Presently no suitable multicut grass for the same period is available which may be grown separately or in mixture with berseem to produce high dry matter yield. The first successful planting of ryegrass in research trials was made in 1976 (Tiwana and Puri, 1984) in India. After that, we became interested …

Herbage Yield Of Annual Ryegrass (Lolium Multiflorium Lam.) And Common Vetch (Vicia Sativa L.) At Different Seeding Rates, M A. Jimenez, O L. Gallegos, M.J L. Castrellon

IGC Proceedings (1977-2023)

Most of the dairy farms in the Central Valley of Mexico have alfalfa and corn silage as major forages. Winters are mild, how­ever, yield of alfalfa is reduced and no corn can be grown. For­age crops as oats, annual ryegrass and common vetch have been grown successfully to supply winter forage (Avendano, 1978; Victoria, 1981). Annual rycgrass generally outyields oats, but a high input of nitrogen is required by annual rye grass (Ciane, 1978). The high cost of N fertilizers prevents their use and cheaper N sources should be sought. Legumes as common vetch grown with annual ryegrass can be …

Performance Of White Clover Cultivars In Mixtures With Orchardgrass In Atlantic Canada, Joanna Fraser, H T. Kunelius

IGC Proceedings (1977-2023)

The climate in the Atlantic Provinces of Canada is ideally suited to pasture production, with up to seven months of grow­ing season in some areas. Moreover, many of the soils are too shallow to support deep-rooted and highly valued forages such as alfalfa (Medicago sativa L.) and corn (Zea mays L.). How­ever, the main limiting factor to pasture production occurs in spring where there are frequent freeze-thaw cycles, which reduce the dependability of snow cover for insulation, and this results in winter injury (Dzikowski et al., 1984). The interest in white clover (Trifolium repens L.) as a …

Comparison Of Ryegrass-White Clover And Competitive Interactions In New Zealand And Wales, W Harris, I Rhodes

IGC Proceedings (1977-2023)

New Zealand and Wales have temperate climates suitable for ryegrass (Lolium species) and white clover (Trifolium repens) pasture. However, pasture management in New Zealand and Wales in fundamentally different. New Zealand pastures are grazed all year, whereas in Wales pastures are mostly not grazed in winter. Moreover New Zealand pastures mostly rely on nitrogen fixed by legumes, whereas nitrogen fertiliser is com­monly applied to Welsh pastures. To consider the basis of differences of pasture management in New Zealand and Wales, data from field experiments at Aberystwyth, Wales (Lat. 52°25'N) and Palmerston North, New Zealand (Lat. 40°20'S) are …

Forage Contribution Of Overseeded Cool-Season Clovers, G D. Mooso

IGC Proceedings (1977-2023)

Warm-season perennial grasses are the foundation of pasture systems in the southeastern U.S. Though well adapted, these species require significant amounts of nitrogen (N) fertilizers to maintain forage production. Nitrogen fertilizers are widely used to improve the yield and quality of grass pastures because it was less expensive and easier to manage than grass-legume mixtures. Cool-season clovers overseeded into dormant peren­nial warm-season swards offer a practical method to extend the grazing season and improve forage quality while capitalizing on the ability of inoculated clovers to supply nitrogen to pro­duction systems thus decreasing production costs (Burton, 1976 ; Hoveland et al., …