Life Sciences Commons^™

Photosynthesis, Yield, Energy Balance, And Water-Use Of Intercropped Maize And Soybean, Elena A. Pelech, Brendan C.S. Alexander, Carl J. Bernacchi

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

By 2050, the U.S. Corn Belt will likely face a 23% increase in leaf-to-air vapor pressure deficit (VPDL), the driving force of evapotranspiration (ET), which may restrict maize yield improvements for rainfed agroecosystems. Alternative cropping systems, such as maize and legume intercrops, have previously demonstrated yield and resource-use advantages over monocultures. In this study, the residual energy balance approach was used to gain insights into how an additive simultaneous maize and soybean intercrop system regulates ET and water-use efficiency (WUE) compared to standard maize and soybean monoculture systems of the U.S. Corn Belt. Experimental field plots were rain-fed and arranged …

Estimating And Modeling Transpiration Of A Mountain Meadow Encroached By Conifers Using Sap Flow Measurements, Simon Joseph Marks

Master's Theses

Mountain meadows in the western USA are experiencing increased rates of conifer encroachment due to climate change and land management practices. Past research has focused on conifer removal as a meadow restoration strategy, but there has been limited work on conifer transpiration in a pre-restoration state. Meadow restoration by conifer removal has the primary goal of recovering sufficient growing season soil moisture necessary for endemic, herbaceous meadow vegetation. Therefore, conifer water use represents an important hydrologic output toward evaluating the efficacy of this active management approach. This study quantified and evaluated transpiration of encroached conifers in a mountain meadow using …

Impacts Of Bloodborne Pathogen Infections On Breeding Ecology And Success In White-Throated Sparrows (Zonotrichia Albicollis), Rachel Weisbeck

All NMU Master's Theses

Bloodborne pathogens have significant and persistent impacts on avian populations worldwide, including decreased long-term survival and population size. Existing research indicates that chronic pathogen infections may have negative impacts on nesting success, such as decreased numbers of offspring, hatching probability, and fledging success. In species with multiple reproductive strategies, pathogen infections may have different impacts based on the role of the infected parent. White-throated Sparrows are a polymorphic species that mate disassortatively and display alternative reproductive strategies associated with color morph. White-striped birds are more aggressive, more promiscuous, and less parental than their tan- striped counterparts. I examined the reproductive …

The Brown Bear Gut Microbiome: A Novel Tool For Conservation & Management, Sarah M. Trujillo

All NMU Master's Theses

Gut microbiomes (GMBs), complex communities of microorganisms inhabiting the gastrointestinal tracts of their hosts, perform countless micro-ecosystem services such as facilitating energy uptake and modulating immune responses. While scientists increasingly recognize the role GMBs play in host health, the role of GMBs in wildlife ecology and conservation has yet to be realized fully. Here, I use brown bears (Ursus arctos) as an ecological model to investigate (1) how both extrinsic and intrinsic factors influence GMB community membership and structure; and (2) the correlation between GMB membership and brown bear health metrics. To achieve these aims, I subsampled archived …

Trophic Ecology Of Juvenile Lean And Siscowet Lake Trout (Salvelinus Namaychush) From U.S. Waters Of Lake Superior, Will Otte

All NMU Master's Theses

In this study, I investigated the spatial overlap, diet similarity, and isotopic niches of juvenile Lean and Siscowet Lake Trout ecotypes across six ecoregions of Lake Superior. Spatially, Lean and Siscowet were observed in overlapping depth distributions. Leans were most abundant in shallow waters (60m). The greatest levels of cohabitation were observed in waters from 40-60m. Trophic position (as measured by δ 15N) was similar for both ecotypes at small sizes (mm), but Siscowet exhibited a higher trophic position than Lean Lake Trout at larger sizes (>400mm) and older ages (>5 years). Base of production (as measured by …

Habitat Associations And Activity Patterns Of Herpetofauna In The Central Platte River Valley, Nebraska, With Notes On Morphometric Characteristics, Jenna M. Malzahn, Andrew J. Caven, Sean Warren, Bethany L. Ostrom, Dennis M. Ferraro

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

The Central Platte River Valley (CPRV) is a unique and biologically important ecoregion, and several studies have conducted localized herpetofauna species inventories. However, there has been significantly less effort to quantify the habitat associations or activity patterns of these species. Habitat associations and activity patterns vary regionally and provide important information for ecosystem management. We deployed a total of 38 traps of 5 different types (pitfall, funnel, hoop, box, and coverboard) across 11 sites (7 terrestrial, 4 aquatic) for an 8-week period in June and July 2019. Our exploratory analyses used generalized linear models with a quasibinomial distribution to examine …

Effects Of Extrinsic And Intrinsic Factors On Meat Quality And Muscle Biology Of Livestock, Yongjie Wang

Graduate Theses and Dissertations

In order to improve the meat quality of livestock, intrinsic and extrinsic factors that impact meat quality have been studied for a long time to optimize production quality. Nutrition, breed, and environment are the three most common factors to improve meat quality and muscle growth. The objective of this thesis is to perform a horizontal comparison of the effects of crude protein levels, breeds, and topsoil on the growth performance, muscle development, and meat quality of livestock, and also a longitudinal analysis using RNA-seq, RT-qPCR, and Western-blot to investigate the changes in genes and proteins related to muscle growth, and …

Sex Differences In The Co-Expression Of Estrogen Receptor Alpha With Corticotropin Releasing Factor, Deborah Ariyibi

Biological Sciences

Women are far more likely to develop anxiety and depression than men. It is believed that the dysregulation of the HPA axis by the binding of corticotropin -releasing factor (CRF) to the corticotropin-releasing factor receptor 1 (CRFR1) contributes to the likelihood of these stress- related disorders. Estrogens acting through Estrogen receptor alpha (ERa) have been shown to increase anxiety production upon activating the HPA axis. In this current study, we explored whether CRF-expressing neurons in various regions of the brain express ERa. The levels of ERa were counted in the bed nucleus of the stria terminalis (BST), the medial preoptic …

Light Level Intensity Alters Anxiety, But Not Memory, During Open-Field And Novel Object Location Tasks In Male Rats, Angelina Tassone

Biological Sciences

Appropriate design and control of testing conditions during assessment of animal behavior is critical to maximize generalizability, replicability, and translational relevance. Some sensory stimuli are often controlled: for instance, during rodent behavioral testing, efforts are commonly made to reduce or eliminate olfactory and auditory distractions. However, less attention is paid to the ambient light level intensity (lux), which may vary even between rooms in the same facility. We sought to explore whether behavior is influenced by the standard illumination intensity in one of our behavioral testing rooms. To this end, we measured anxiety-like behaviors, exploration, and spatial memory performance in …

How Salivary Glands Recover From Fibrotic Injury, Gabriella Majka

Biological Sciences

Extracellular matrix deposition is required for repair after injury, but if left unresolved can result in fibrosis. Fibrosis is an excess deposition of extracellular matrix proteins following injury or aging that leads to eventual organ dysfunction. One surgical model that we have used to study mechanisms of fibrosis is the salivary gland ductal ligation model. During the process of ligation, a clip is placed on the main ducts of the submandibular (SMG) and sublingual gland (SLG) which leads from the salivary glands to the mouth. This causes the gland to atrophy, or waste away, resulting in decreased acinar cell differentiation …

Veganic Farming In The United States: Farmer Perceptions, Motivations, And Experiences, Mona Seymour, Alisha Utter

Urban and Environmental Studies Faculty Works

Veganic agriculture, often described as farming that is free of synthetic and animal-based inputs, represents an alternative to chemical-based industrial agriculture and the prevailing alternative, organic agriculture, respectively. Despite the promise of veganic methods in diverse realms such as food safety, environmental sustainability, and animal liberation, it has a small literature base. This article draws primarily on interviews conducted in 2018 with 25 veganic farmers from 19 farms in the United States to establish some baseline empirical research on this farming community. Its qualitative perspectives illuminate farmer perceptions of and experiences with veganic growing, including definitions, knowledge acquisition, values, and …

Effects Of Scarification, Phytohormones, Stratification, Soil Types And Warming On The Germination And/Or Performance Of Three Tamaulipan Thornscrub Species, Paula Luera

Theses and Dissertations

The Tamaulipan thornforests of south Texas and northeast Mexico are an ecologically and economically important conservation hotspot. Thornforest restoration is limited by native tree and shrub seedling availability for planting. Seedling shortages arise from low seed availability and knowledge gaps regarding best practices for germinating and growing the 70+ thornforest species desired for restoration plantings. To fill key knowledge gaps, we investigated three ecologically important thornforest species with low or highly variable germination or seedling survival rates: Ebenopsis ebano, Cordia boissieri, and Zanthoxylum fagara. For each, we quantified the effects of different dosages of chemical seed treatments …

Exploring The Role Of Stigmatic Exudate In The Water Lily (Nymphaceae) Pollination Mechanism Using N. Ampla (Salisb. Dc.), Luis Uribe

Theses and Dissertations

Water lilies are the only known plant group that uses hyperactive nectar glands to divest pollinators of their pollen. The nectar in Nymphaea ampla is thought to contain secondary metabolites that increase pollen deposition possibly by modifying pollinator behavior. This was explored utilizing visitation and fecundity data from the field coupled with survival and behavioral experiments in the laboratory. Replacing nectar with water reduced seed set in N. ampla which was attributed to reduced visitation in water-bearing flowers and not to effects on pollinator detention time. Exposure to nectar did not reduce survivability in Apis mellifera. Pollen and nectar foragers …

Bullet-Proof Boll Weevil: The History Of Boll Weevil Eradication, Evan A. Berg

Theses and Dissertations

Farmers and entomologists have all experimented with various methods to find the best way to defeat the United States' boll weevil. The techniques themselves, while expansive, can be examined within the scope of the years that they were used. This provides an exciting insight into how cotton pest management became more complex as the decades moved on and revealed how the science of cotton pest management evolved to deal with the boll weevil and other future cotton threats.

Characterization Of Soil Nematode Community As Influenced By Weedy Plants And Edaphic Properties, Orlando Garcia

Theses and Dissertations

Nematodes are one of the most critical species globally as they are part of most nutrient recycling. While nematodes play a vital role in nutrient cycling, little is known about them from an ecological standpoint. The majority of current research has focused on a singular component of the community, being those of herbivore/plant-parasitic nematodes. In this study, the community shifts of the nematode trophic groups were analyzed as influenced by native and invasive grasses species in the Lower Rio Grande Valley (LRGV) with the addition of edaphic soil properties.

In our study, the results indicate changes in the composition of …

A Gis-Based Model To Assess On-Site Sewage Facility (Ossf) Contamination Risk To Local Water Resources, Alvaro Garcia

Theses and Dissertations

In a collaborative effort between Texas Water Resources Institute (TWRI), Cameron County Public Health (CCPH), Texas A&M AgriLife Extension (TAMAE), and the University of Texas Rio Grande Valley (UTRGV), a GIS database that includes relevant OSSF information, such as location, system age, lot size, and other important parameters was created.

This OSSF database, along with publicly available GIS data, was used to create an integrative GIS-based risk assessment model where OSSF risk parameters were assigned a risk factor and combined into a spatial contamination risk for surrounding areas and their receiving waterbodies. Parameters were broken down into two categories: environmental …

Early Embryology In Collembola With An Emphasis On Wing Development, Samantha A. Gonzalez

Theses and Dissertations

The primary objective of this study was to further the understanding of the wing origin in insects. Currently there are several theories which are popular such as the tergum theory, the pleural plate theory, and the dual theory of wing origin. Studies for these theories have been done on crustaceans, the ancestors to modern day insects. By utilizing a pre insect hexapod, it may be possible to better understand the transition to insect wings. Members of the Collembola species Hypogastrurid are one of these pre-insect hexapods which may provide a clue into origins of wing development. During this study, the …

Duet Phonology And Syntax Of The Red-Crowned Parrots In South Texas, Abigail Pozulp

Theses and Dissertations

Bird behavioral interaction systems show a preference for temporal precision. This preference is exemplified in the way many species avoid masking of vocal signals. Antiphonal duetting in songbirds suggest that overlapping notes are a sign of poor temporal coordination which can signify a weak pairbond, a possible cue for conspecifics seeking to usurp territories or mates. However, parrots (Psittacidae) are accomplished yet understudied duetters in nature. I recorded antiphonal duets produced by a wild population of red-crowned parrots (Amazona viridigenalis) in Brownsville, Texas. Temporal and acoustic variation of signals was assessed within and across a sample of mated …

Development Of A Novel Strategy To Improve Checkpoint Immune Response In Pancreatic Cancer, Poornima Devi Shaji

Theses and Dissertations

Pancreatic Cancer is the 3rd lethal causing cancers in United States with a survival rate less than 5-7%. In advanced unresectable pancreatic cancer, treatment options are restrained to surgery because of its extreme aggressiveness. Immunotherapy, one of the current advanced treatments has shown promising response in other cancers. However, this therapy is limited in pancreatic cancer due to desmoplasia and fibrotic tumor microenvironment (TME).

Our superparamagnetic iron oxide nanoparticles (SPIONS) of curcumin (Curcuma longa, principal curcuminoid of turmeric) have potential ability to inhibit desmoplasia and tumor stroma with an increased bioavailability. This would soften up the tumors for …

Home Range Dynamics And Juvenile Dispersal Of Gray Hawks In The Lower Rio Grande Valley, Michael Stewart

Theses and Dissertations

Using GPS-GSM transmitters I determined when 14 juvenile Gray Hawks (Buteo plagiatus) in the Lower Rio Grande Valley of Texas fledged from their natal areas and how far they traveled once they dispersed. These transmitters also allowed me to calculate home range sizes for 22 adults. Additionally, with the GPS-GSM transmitters and 15 VHF transmitters, I discovered that adult Gray Hawks in the study area remained in their territories year-round. Home range sizes were calculated using the minimum convex polygon estimator, the estimation of kernel home-range, and the estimation of kernel Brownian bridge home-range. The same three methods allowed me …

The Yearly Financing Need Of Providing Paid Maternity Leave In The Informal Sector In Indonesia, Adiatma Y. M. Siregar, Pipit Pitriyan, Donny Hardiawan, Paul Zambrano, Mireya Vilar-Compte, Graciela Ma Teruel Belismelis, Meztli Moncada, David Tamayo, Grace Carroll, Rafael Perez-Escamilla, Roger Mathisen

Department of Public Health Scholarship and Creative Works

Background: The economic cost of not breastfeeding in Indonesia is estimated at US$1.5–9.4 billion annually, the highest in South East Asia. Half of the 33.6 million working women of reproductive age (WRA) in Indonesia (15–49 years) are informal employees, meaning they are working as casual workers or they are self-employed (small scale business) and assisted by unpaid/family worker(s). No specific maternity protection entitlements are currently available for WRA working informally in Indonesia. This study aims to estimate the financing need of providing maternity leave cash transfer (MCT) for WRA working in the informal sector in Indonesia. Method: The costing methodology …

Breastfeeding Media Coverage And Beliefs During The Covid-19 Pandemic In Mexico: Implications For Breastfeeding Equity, Mireya Vilar-Compte, P. Gaitán‐Rossi, E. C. Rhodes, V. Cruz‐Villalba, R. Pérez‐Escamilla

Department of Public Health Scholarship and Creative Works

Background: Because breastfeeding offers short- and long- term health benefits to mothers and children, breastfeeding promotion and support is a public health priority. Evidence shows that SARS-CoV-2 is not likely to be transmitted via breastmilk. Moreover, antibodies against SARS-CoV-2 are thought to be contained in breastmilk of mothers with history of COVID-19 infection or vaccination. WHO recommends direct breastfeeding as the preferred infant feeding option during the COVID-19 pandemic, even among women with COVID-19; but conflicting practices have been adopted, which could widen existing inequities in breastfeeding. This study aims to describe how information about breastfeeding was communicated in Mexican …

Absorption Kinetics Of Berberine And Dihydroberberine And Their Impact On Glycemia: A Randomized, Controlled, Crossover Pilot Trial, Jessica M. Moon, Kayla M. Ratliff, Anthony M. Hagele, Richard A. Stecker, Petey W. Mumford, Chad M. Kerksick

Faculty Scholarship

Berberine is a natural alkaloid used to improve glycemia but displays poor bioavailability and increased rates of gastrointestinal distress at higher doses. Recently, dihydroberberine has been developed to combat these challenges. This study was designed to determine the rate and extent to which berberine appeared in human plasma after oral ingestion of a 500 mg dose of berberine (B500) or 100 mg and 200 mg doses of dihydroberberine (D100 and D200). In a randomized, double-blind, crossover fashion, five males (26 ± 2.6 years; 184.2 ± 11.6 cm; 91.8 ± 10.1 kg; 17.1 ± 3.5% fat) completed a four-dose supplementation protocol …

The Role Of The Erbb Signaling Pathway In Cardiovascular Progenitor Cell-Based Repair, Christopher Ramos

Electronic Theses, Projects, and Dissertations

Adult mammalian hearts lack self-renewal and proliferative capabilities necessary for cardiovascular regeneration. Current treatments using cardiac progenitor cells (CPCs) for cell-based repair do not restore cardiac function in patients who experience a myocardial infarction (MI). Our laboratory has been studying Islet-1+ neonatal CPCs as a promising candidate for cell-based repair due to their ability to significantly improve cardiac function after MI in sheep. The current study addresses the hypothesis that the ERBB pathway is linked to the Hippo-pathway to activate YAP1 by the involvement of an autocrine loop that upregulates neuregulin (NRG). In our sheep model of MI and cardiovascular …

Cardenolide, Potassium, And Pyrethroid Insecticide Combinations Reduce Growth And Survival Of Monarch Butterfly Caterpillars (Lepidoptera: Nymphalidae), Annie J. Krueger, Emily A. Robinson, Thomas J. Weissling, Ana M. Vélez, Troy D. Anderson

Department of Entomology: Faculty Publications

The monarch butterfly, Danaus plexippus L., has evolved to be insensitive to milkweed cardenolides via genetic modifications of Na⁺/K⁺-ATPase. There is concern for insecticide exposures near agriculture, with little information on monarch caterpillar toxicology. It is unclear how cardenolide insensitivity may affect the sensitivity of monarch caterpillars to pyrethroid insecticides. Additionally, potassium fertilizers may affect monarch caterpillar physiology and cardenolide sequestration. Here, we investigated the growth, survival, and development of caterpillars exposed to the cardenolide ouabain, bifenthrin, and potassium chloride (KCl) alone and in combination. Caterpillars were either exposed to (1) ouabain from third- to fifth-instar …

Reintegrating Biology Through The Nexus Of Energy, Information, And Matter, Kim L. Hoke, Sara L. Zimmer, Adam B. Roddy, Mary Jo Ondrechen, Craig E. Williamson, Nicole R. Buan

Department of Biochemistry: Faculty Publications

Information, energy, and matter are fundamental properties of all levels of biological organization, and life emerges from the continuous flux of matter, energy, and information. This perspective piece defines and explains each of the three pillars of this nexus. We propose that a quantitative characterization of the complex interconversions between matter, energy, and information that compose this nexus will help us derive biological insights that connect phenomena across different levels of biological organization. We articulate examples from multiple biological scales that highlight how this nexus approach leads to a more complete understanding of the biological system. Metrics of energy, information, …

Classifying Electrocardiogram With Machine Learning Techniques, Hillal Jarrar

Master's Theses

Classifying the electrocardiogram is of clinical importance because classification can be used to diagnose patients with cardiac arrhythmias. Many industries utilize machine learning techniques that consist of feature extraction methods followed by Naive- Bayesian classification in order to detect faults within machinery. Machine learning techniques that analyze vibrational machine data in a mechanical application may be used to analyze electrical data in a physiological application. Three of the most common feature extraction methods used to prepare machine vibration data for Naive-Bayesian classification are the Fourier transform, the Hilbert transform, and the Wavelet Packet transform. Each machine learning technique consists of …

Spatial Distribution Of Conspecific Genotypes Within Chimeras Of The Branching Coral Stylophora Pistillata, Gabriele Guerrini, Dor Shefy, Jacob Douek, Nadav Shashar, Tamar L. Goulet, Baruch Rinkevich

Faculty and Student Publications

Chimerism is a coalescence of conspecific genotypes. Although common in nature, fundamental knowledge, such as the spatial distribution of the genotypes within chimeras, is lacking. Hence, we investigated the spatial distribution of conspecific genotypes within the brooding coral Stylophora pistillata, a common species throughout the Indo-Pacific and Red Sea. From eight gravid colonies, we collected planula larvae that settled in aggregates, forming 2–3 partner chimeras. Coral chimeras grew in situ for up to 25 months. Nine chimeras (8 kin, 1 non-related genotypes) were sectioned into 7–17 fragments (6–26 polyps/fragment), and genotyped using eight microsatellite loci. The discrimination power of each …

Rcb Initiates Arabidopsis Thermomorphogenesis By Stabilizing The Thermoregulator Pif4 In The Daytime, Yongjian Qiu, Elise K. Pasoreck, Chan Yul Yoo, Jiangman He, He Wang, Abhishesh Bajracharya, Meina Li, Haley D. Larsen, Stacey Cheung, Meng Chen

Faculty and Student Publications

Daytime warm temperature elicits thermomorphogenesis in Arabidopsis by stabilizing the central thermoregulator PHYTOCHROME INTERACTING transcription FACTOR 4 (PIF4), whose degradation is otherwise promoted by the photoreceptor and thermosensor phytochrome B. PIF4 stabilization in the light requires a transcriptional activator, HEMERA (HMR), and is abrogated when HMR’s transactivation activity is impaired in hmr-22. Here, we report the identification of a hmr-22 suppressor mutant, rcb-101, which surprisingly carries an A275V mutation in REGULATOR OF CHLOROPLAST BIOGENESIS (RCB). rcb-101/hmr-22 restores thermoresponsive PIF4 accumulation and reverts the defects of hmr-22 in chloroplast biogenesis and photomorphogenesis. Strikingly, similar to hmr, the null rcb-10 mutant impedes …

Climate And Seasonality Drive The Richness And Composition Of Tropical Fungal Endophytes At A Landscape Scale, Shuzo Oita, Alicia Ibáñez, François Lutzoni, Jolanta Miadlikowska, József Geml, Louise A. Lewis, Erik F. Y. Hom, Ignazio Carbone, Jana M. U’Ren, A. Elizabeth Arnold

Faculty and Student Publications

Understanding how species-rich communities persist is a foundational question in ecology. In tropical forests, tree diversity is structured by edaphic factors, climate, and biotic interactions, with seasonality playing an essential role at landscape scales: wetter and less seasonal forests typically harbor higher tree diversity than more seasonal forests. We posited that the abiotic factors shaping tree diversity extend to hyperdiverse symbionts in leaves—fungal endophytes—that influence plant health, function, and resilience to stress. Through surveys in forests across Panama that considered climate, seasonality, and covarying biotic factors, we demonstrate that endophyte richness varies negatively with temperature seasonality. Endophyte community structure and …