Texas A&M University – Corpus Christi
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Funeral flowers on the Fireplace
No full textLarge Bouqet of Funeral flowers sitting on the Fireplace with two photographs on the mante
An analysis of the El Nino Southern Oscillation's effects on tropical cyclones
No full textIn the 20 years, 2,023 tropical cyclones provide us a robust sample size to study the impact of the El Nino Southern Oscillation on tropical cyclone with respect to precipitation on a global scale. It is clear that the El Nino Southern Oscillation does play a significant role in the intensity, location and magnitude of tropical cyclones. We also found that the depending on which phase of ENSO and whether it’s a major or minor tropical cyclone, different parts of the globe have experienced more or less precipitation that can be attributed to tropical cyclone. How does ENSO influence frequency of tropical cyclones globally?
What is the global precipitation contribution from tropical cyclones? How does ENSO influence global precipitation that is contributed by minor and major hurricanes?
Long-term vertical-land-motion investigation with space and terrestrial geodetic techniques near San Leon, Texas, USA
No full textMonitoring vertical land motion (VLM) along coastlines, which influences the dynamics of sea level changes in relation to the land, is a challenging task due to its inherent high spatiotemporal variability and limited availability of observations. This study aimed to investigate the rates, patterns, and drivers of land subsidence near the coastal town of San Leon, TX, United States, since the 1990s, utilizing a range of space and terrestrial geodetic techniques. These techniques included interferometric synthetic aperture radar (InSAR), global navigation satellite systems (GNSS), tide gauge (TG), and satellite radar altimetry (SRA). The small baseline subset (SBAS) InSAR method was adopted to process 254 images from three synthetic aperture radar (SAR) sensors, i.e., ERS-2 between 1995 and 1999, ALOS-1 PALSAR between 2006 and 2011, and Sentinel-1 between 2016 and 2020. The results from InSAR subsidence maps were verified by comparing with high-accuracy vertical positioning observations at ten continuously operating GNSS (cGNSS) stations. Within the study area, a special attention was given to the Eagle Point TG station where sea level has been significantly rising relative to the sinking land. Long-term time series of land subsidence at Eagle Point obtained from sea-level difference between TG and SRA observations were confirmed and compared against InSAR and the cGNSS station observations recorded in close proximity. Gaussian Process regression (GPR) was then employed to model the VLM processes at Eagle Point using: (1) the combined results of InSAR and sea-level difference (i.e., GPR 1), and (2) the InSAR results alone (i.e., GPR 2). A 0.9 mm/yr divergence was found between GPR 1 and GPR 2 models, indicating the potential to accurately estimate long-term VLM with InSAR standalone measurements even if multi-year observation gaps intermittently occur, especially for inland areas where measurement data from other geodetic techniques, such as GNSS, TG, and SRA, are not available. Further investigations suggest that land subsidence around Eagle Point since 1998 was related to anthropogenic activities such as hydrocarbon pumping from oil and gas wells that were situated in close proximity to the TG station.This research was supported by the U.S. Department of Commerce-National Oceanic and Atmospheric Administration (NOAA) through the University of Southern Mississippi (USM) under the terms of Agreement [No. NA13NOS4000166]. This work was also supported by the National Science Foundation (NSF) under award No. 2131263. The authors also thank the Open Access Publication Fund provided by the Mary and Jeff Bell Library at Texas A&M University-Corpus Christi (TAMU-CC) . Opinions expressed by authors herein do not necessarily reflect views of NOAA, NSF or USM. The authors are grateful to Dr. Laha Ale for his valuable review and insightful comments on the article
Development of bis-bipyridinium and anthracene carboxyimide-based stimuli-responsive soft matter
No full textA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in ChemistryThis thesis focuses on the design and synthesis of an array of novel amphiphilic and polymeric molecules as precursors for developing dynamic stimuli-responsive supramolecular materials by harnessing the competency of non-covalent interactions. Over the past decades, bipyridinium-based derivatives have gained tremendous attention due to their applicability as functional units in tunable supramolecular complexes. The innate propensity of functionalized bipyridinium salts to serve as a ?-electron deficient acceptor allows them to undergo ?-? stacking donor-acceptor CT interactions in the presence of ?-electron rich organic molecules. This characteristic feature was employed to develop novel bipyridinium-functionalized amphiphiles and bio-polymeric materials that are capable of engaging in molecular recognition with and facilitating the extraction of melatonin, a neurotransmitter from water. The first project reports the design and development of heptyl and glycol-bridged bis-bipyridinium-based gemini amphiphiles that can undergo template-directed self-assembly. Previous studies indicated that the electrophilic aromatic nature of tetra-cationic bis-bipyridinium gemini amphiphiles can be exploited to form ?-? stacking charge-transfer interactions with ?-electron rich molecules. Thus, in an effort to establish structure-property relationships and understand the effect of the bridging unit, varied bridged bis-bipyridinium gemini amphiphiles were synthesized. They were investigated for their use of melatonin as a template for directed self-assembly processes. The charge-transfer interactions between the units lead to absorption band formation in the visible region of the electromagnetic radiation that can be exploited for various material applications. Upon comparing, the two derivatives in detail, their micellization behavior, surface properties, thermodynamic parameters, UV-Vis absorption, and micellar size exhibited similar characteristics. However, the heptyl-bridged gemini amphiphile responded to templation much more strongly, while the glycol-bridged gemini amphiphile exhibited higher solubility, they both portrayed excellent amphiphile and surface-active characteristics. The second part of this work focuses on employing ?-electron deficient bipyridinium units to design and process functional lipoic ester-based polymeric materials for the indole-base molecular targets from water. A series of lipoic-ester based-bipyridinium functionalized polymers with varying alkyl tail lengths were developed and studied to determine structure-property correlations and analyze their material characteristics. Out of the eight-novel functionalized polymeric materials, bipyridinium-bridged lipoic ester polymer (BLEP) formed polymeric sheets while nonyl-bipyridinium-functionalized lipoic ester polymer (9C-BFLEP) formed coacervates in water. Both materials showed comparable and acceptable efficiency in adsorbing melatonin out of solution by harnessing ?-? stacking charge-transfer interactions in conjugation with the hydrophobic effect. This approach provided a quick and promising method for the remediation of indole-cored molecules from water. Lastly, an anthracene carboxyimide derivative was synthesized with the ability to undergo a photo-induced [4+4] cycloaddition dimerization process. The dimerization can easily be reversed upon heating. The compound was found to be able to have a special feature that allows them to undergo single crystal-to-single crystal photo-dimerization upon exposure to UV light. This controlled switchable characteristic property of anthracene carboxyimide are unique and can be utilized for developing tunable molecular switches with applications where stimuli-responsive materials are required.Environmental ScienceCollege of Scienc
Coastal residential canals harbor distinct water quality conditions and phytoplankton community composition
No full textAs urbanization increases, many regions around the globe are seeing an increase in the number of residential canal systems along their coastlines. These canals possess unique attributes that may facilitate water quality degradation, namely shallow depths, susceptibility to urban runoff, and limited flushing. Despite this, there has been little research on the water quality and phytoplankton dynamics of these systems. In this study, water quality and phytoplankton biomass/composition were quantified once per month in the fall and winter, and twice per month in the spring and summer, over a 1-year period at three sites along a mouth-interior gradient of a canal system on North Padre Island (Corpus Christi, Texas, USA). It was hypothesized that interior canal sites would exhibit symptoms of water quality degradation more regularly than a site at the mouth, and interior canal sites would also have higher chlorophyll a and distinct phytoplankton community composition compared to the mouth. Results showed that the mouth site exhibited lower inorganic nutrient concentrations and less pronounced variability in salinity and nutrients than the interior canal sites. Chlorophyll a was 2.5-3-fold higher in the canal sites than at the mouth on average, and diatoms dominated at the mouth while a more diverse assemblage dominated at the canal sites. Episodic to persistent hypoxia was observed at the canal sites, but not at the mouth. These findings show that artificial coastal residential canal systems have distinct and less desirous water quality conditions and phytoplankton communities, pointing to a need for additional research on the attributes of canals that foster these conditions to support effective ecosystem health management efforts
A comparative analysis of georeferencing techniques for crop canopy height estimation using UAS photogrammetry
No full textA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geospatial Systems EngineeringIn the rapidly evolving fields of geospatial engineering and precision agriculture, the accuracy and reliability of georeferencing techniques and Uncrewed Aircraft System (UAS) methodologies are crucial for effective decision-making and crop management. This research aims to enhance UAS Structure-from-Motion (SfM) photogrammetry data quality for crop canopy height estimation in high-throughput phenotyping. The study investigates and compares the accuracy and reliability of three distinct methods used for georeferencing of the UAS imagery, which subsequently enables more accurate SfM 3D reconstruction: Global Navigation Satellite System (GNSS) without any correction aiding (GNSS-only), GNSS+Real-Time Kinematic (RTK), receiving RTK corrections from a local base station, GNSS+Real-Time Network (RTN), receiving RTK corrections from the Texas Department of Transportation (TxDOT) GNSS reference station network. The study further assesses the correlation between manually measured plant heights and those estimated from UAS-SfM point cloud data, exploring three different Digital Terrain Model (DTM) generation techniques. The research was conducted at the Texas A&M AgriLife Research and Extension Center in Corpus Christi, Texas, USA, on corn crops grown during the 2022 agricultural season. The three DTM generation methods under consideration included 1) using a DTM acquired from a flight conducted before plant emergence, 2) creating a DTM by interpolating ground height points, and 3) implementing automatic classification algorithms. Findings initially revealed that the GNSS+RTK method consistently outperformed the other georeferencing techniques, delivering more accurate results across various dates. Despite these overall trends, there were some instances where the GNSS+RTK method did not consistently outperform the other techniques. The use of one ground control point (GCP) improved georeferencing accuracy compared to scenarios with no GCPs used, while GNSS-only without correction aiding reported the least accurate results as expected. Regarding plant height estimation, the highest accuracy was generally achieved with greater canopy cover percentages, with the optimal percentage varying depending on the data collection date and DTM creation method. The highest coefficient of determination (R2) of 0.92 between manual measurements and UAS-SfM derived plant heights was found when the DTM was either interpolated from ground height points or obtained from a pre-emergence flight.Geospatial Surveying EngineeringCollege of Scienc
A diversity baseline of benthic macrofauna along the northwestern insular slope of Cuba (Gulf of Mexico)
No full textA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Marine Biology.The Gulf of Mexico (GoM) is a unique ecosystem due to the physical characteristics influenced primarily by the Mississippi River in the North and the Loop Current, which originates in the south, resulting in a gradient of organic to carbonate sediment composition. The continental slope of the northern (US) and southwestern (Mexico) portions of the GoM are generally well studied; however, very little is known about the southeastern GoM along the slope of Cuba. To fill this knowledge gap, sediment cores were collected in 2017 at nine stations (974–1580 m depth) to gather baseline data and determine controls on the deep-sea benthic macrofauna community. Oceanographic data indicated a stratified water column typical of an oligotrophic ocean and no evidence of hypoxia. Sediment texture and composition indicated a west-east gradient likely determined by downslope transport of terrigenous material in the eastern part with a high proportion of carbonate in the west. Heavy metals (Cu, Hg, Pb, and Zn) at concentrations known to cause benthic effects were present in the east near the major city of Havana, with the macrofauna community showing characteristics indicative of environmental stress. Stations had a low overall average diversity (15 families/79 cm2) and abundance (7,980/ m2), with high variability among replicates within the stations. The diversity was 48% less, and the abundance was 14% less than in the northern GoM. The major factors influencing macrofauna communities in the continental slope off northwestern Cuba are most likely the lack of organically rich sediment, low sediment deposition rates, and the strong current.Life SciencesCollege of Scienc
A quality improvement project to decrease screen use in children aged 0-5 via a parental education program
No full textCritical brain development occurs between the ages of zero and five (American Academy of Pediatrics [AAP], 2016). The digitalization of childhood impacts how children experience play, learn, and build relationships (Hutton et al., 2020). The purpose of this QI project was to increase provider use of the “Family Media Plan’” and determine if a parent education would decrease screen-time. This QI project sought to answer the question, will the use of screen-time education, increase provider use of the “Family Media Plan,” increase parent knowledge and decrease screen-time, in children under five years? This QI initiative was reviewed by the Texas A&M University- Corpus Christi Institutional Review Board (IRB) for project/study and approval to proceed was received. The setting for this QI project was a primary care clinic. Participants were a recruited from patients under five, that presented for well visit. Pre-test, post-test design was selected to evaluate efficacy of the intervention. A modified version of the HomeSTEAD survey was selected to measure behavior change. Eight families completed the initial survey and received the educational intervention. A mean of 115.714 minutes was calculated to the question “on average, how much time does the child spend on screened devices per day?” Seven (n-7) families responded to the follow-up telephone interview. A mean of 102.857 minutes was calculated, demonstrating a 12.858-minute decrease and resulting in an 11% decrease from the pre-intervention response. A simple chart review was conducted to identify use of the “Family Media Plan.” Seven of the seven participant EHR had a complete “Family Media Plan.” This study only addressed the amount of time spent with screened media devices and did not differentiate between educational and non- educational programming, nor did it address the varying impact of screen-time versus indoor/outdoor play.College of Nursing and Health Science
Benthic infaunal long term response to wastewater diffuser discharge in Lavaca Bay, Texas
No full textA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Science.The Lavaca-Colorado Estuary (LCE) is one of seven major estuarine systems located on the Texas coast. As the second largest estuary in Texas, the LCE provides local and statewide residents with industrial, recreational, and agricultural benefits and historically known to be an abundant and diverse ecosystem for marine organisms. Previous studies have shown there has been long-term decline in benthic abundance, biomass, and diversity in the LCE since 1988. A more recent study found that in fact there was a long-term increase in benthic abundance, biomass, and diversity in the LCE since 1993. Multiple stressors, natural and anthropogenic in origin, are affecting biological community structure. Therefore, these stressors are transforming ecosystems. The purpose of this research is to continue the previous studies to determine if long-term diffuser discharge has any effect on benthic infauna communities in the sediment of Lavaca Bay. This thesis analyzes a 29-year long-term monitoring/time series dataset that was designed to evaluate the impact a discharge pipeline had on constituents of ecological and biological conditions in Lavaca Bay. The purpose of this study was to answer environmental questions about Lavaca Bay. The primary question is: Does the industrial discharge affect the ecological health of Lavaca Bay? If so, are the benthos being affected more near the diffuser site, or is the effect constant throughout the bay? The overall goal was to perform an analysis to determine which parts of the bay are being most affected and to reach conclusions about the overall bay health. Bay health can be indicated by a decline in benthic integrity (i.e., diversity), decreased survival rates of organisms exposed to sediments, and sediment chemical contaminant concentrations over threshold limits. The results revealed that industrial discharge does affect ecological health in localized areas near the outfall. Sediment characteristics closest to the outfall had higher combinations of silt and clay, possibly due to diffuser outflows disturbing the sediment and increasing turbidity. The water column had lower pH, temperature, and DO closer to the outfall. Survival predictions showed an increase over time suggesting that the diffuser does not negatively affect the survival rates of the benthic communities within the bay. However, benthic community diversity means were higher as distance increases away from the outfall. Therefore, even though the diffuser isn’t negatively affecting the overall benthic bay health, it has a negative local effect when compared to stations further away from the outfall area.Physical and Environmental SciencesCollege of Scienc
Conservation genomic assessment of two imperiled freshwater fishes, Leon Springs Pupfish (Cyprinodon Bovinus) and Pecos Gambusia (Gambusia Nobilis)
No full textFreshwater fishes are increasingly recognized as one of the most imperiled groups of vertebrates, with a growing body of research highlighting the significant threat posed to their biodiversity by human activities. Anthropogenic actions, such as habitat modification and destruction, pollution, overexploitation, and the introduction of invasive species, have led to a decline in the number of freshwater fish species worldwide. Addressing this imminent crisis requires comprehensive conservation efforts, stricter regulatory frameworks, habitat restoration, and heightened public awareness. This project aimed to provide data important for the conservation of two imperiled desert freshwater fishes, Cyprinodon bovinus and Gambusia nobilis, both of which are federally listed as endangered and have undergone range contractions throughout the western United States due to anthropogenic activity. Using genomic techniques, I assessed patterns of genetic diversity within and between populations of both species and screened for evidence of hybridization with introduced congeners. No evidence of contemporary hybridization was found between C. bovinus and C. variegatus, but admixture was detected among G. nobilis and its respective invasive congeners (G. geiseri and G. affinis). Fine-scale population structure was evident for both species of interest and estimates of effective population sizes were low for both species. The results of the study will help update conservation management plans to help mitigate the threat of extinction for both species.Life SciencesCollege of Scienc