Texas A&M University-Kingsville: AKM Digital Repository
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Design and assessment of agrivoltaics systems for energy cane farms in Texas
No full textDue to climate change, natural disasters, and other unexpected events, such as the COVID-19 pandemic, farmers in Texas are facing the difficult task of maintaining a profit from their agriculture business. The concept of agrivoltaics creates a system that integrates renewable energy generation and agriculture with one another. This allows farmers to continue receiving income through their agricultural business while providing energy resilience through an environmentally friendly approach. This project evaluates the potential of implementing an agrivoltaic system using solar panels in an energy cane farm located in Weslaco, Texas. The biomass crop is of interest for an agrivoltaic system as it is low input and is drought resistant. Various databases and industry standards are implemented to optimize and design the agrivoltaics system. Data collected from the energy cane farm in Weslaco, Texas is used throughout the project and aid in creating a maintenance schedule for the agrivoltaics system. Additionally, software such as HomerPro, SolidWorks, and MATLAB are used throughout the process to aid the optimization efforts of the system. The final conceptual design increased the vertical mobility of the structure by integrating a pulley system. The sensitivity analysis of the agrivoltaics system in an energy cane farm showed that increasing shading density decreased the dry biomass yield, but the optimal shading density for maximizing energy production depended on the potential for selling surplus energy to the grid and the local cost of electricity
Morphological and anatomical development of Citrus sinensis (Orange) and Solanum lycopersicum (Tomato) grown with non-conventional water sources
No full textThis experiment focuses primarily on cultivation of tomato (Solanum lycopersicum) and citrus (Citrus sinensis) irrigated with freshwater diluted with different concentrations of saline water. There are 463,365 hectares of greenhouses in the United States, and each hectare consumes 158,280 liters of fresh water per day. It would be beneficial to reduce the amount of freshwater used in greenhouse and nursery operations because of the scarcity of freshwater as a natural resource. This study employs a variety of low concentrations of saline water, including 5.81 mS/cm, 5.93 mS/cm, 6.14 mS/cm, 6.42 mS/cm, 6.8 mS/cm, and 7.25 mS/cm for citrus, and 6.86 mS/cm, 8.15 mS/cm, 8.94 mS/cm, 9.43 mS/cm, and 9.85mS/cm for tomato to dilute the freshwater used to irrigate the plants. Morphological and anatomical measurements were taken from the species to assess growth and development due to the treatments. The results show that there is no significant difference between morphological and anatomical development of the control and treated plants in all the parameters assessed. This indicates that saline water up to 9.85 mS/cm could be used to dilute freshwater in greenhouse and nursery production of the species without compromising the anatomical and morphological growth and development of Solanum lycopersicum (Tomato) and Citrus sinensis (orange). The results of the study indicate that there was no significant difference in growth and development between the morphological and anatomical dimensions of the species grown with mildly diluted freshwater source. Also, the study further concludes that large amounts of freshwater resources can be saved by diluting freshwater with saline water in greenhouse production of the species
Characterization of the Bot gummosis pathogen Lasiodiplodia iranensis isolated from Texas citrus
No full textCitrus is one of the most important fruit crops in United States and in the world. Lasiodiplodia iranensis, in the family Botryosphaeriaceae, is a fungal pathogen that cause dieback of citrus in nurseries and in the groves. The plants affected by this fungus show symptoms of necrosis, die back and gummosis on branches and stems. The geographical distribution of this pathogen is identified in some of the major citrus growing regions of the world. Young citrus trees in Hidalgo County, Texas displayed some of the symptoms listed above, and L. iranensis was isolated from the symptomatic plants. Therefore, the objectives of this study were (i) to confirm L. iranensis as the causing pathogen of the citrus dieback in nursery trees, (ii) to characterize the fungal morphology and susceptibility to commercial fungicides (iii) determine the host range of L. iranensis on citrus varieties. Results showed that healthy citrus trees inoculated with 2-week old mycelial plugs of L. iranensis developed similar symptoms to those observed in the original infected plants and the pathogen was re-isolated from symptomatic tissues, thereby satisfying Koch’s postulates. The fungus actively grows in PDA media and matured 2-weeks post inoculation. Stem cuttings from fourteen citrus varieties were inoculated with L. iranensis plugs to assess virulence and pathogenicity of the fungus. It was observed that the stems were covered by the mycelium within 4 days post inoculation (DPI) in most of the varieties. This study confirms the presence of L. iranensis in Texas and help characterize the fungus and asses the virulence and pathogenicity in different citrus varieties
Impact of the Nigerian government's fuel subsidy removal: data analysis and suggestions
No full textThe decision to eliminate the fuel subsidy in Nigeria has sparked considerable debate. Proponents argue that the savings could help reduce national debt and boost economic growth through infrastructure investments, while opponents express concern over the potential negative impacts on individuals and businesses. This study examined the effects of fuel subsidy removal on Nigeria's economic growth using conditional probability and Bayes' theorem within an ex-post facto research framework. Data spanning from 1985 to 2023, covering fuel subsidy payments and GDP, were obtained from the National Bureau of Statistics and the Central Bank of Nigeria. The results from multiple regression analysis indicated a strong positive correlation between the removal of fuel subsidies and economic growth, with the removal resulting in approximately 29.6% of the variance in economic growth, statistically significant at p < 0.05. Additionally, the study assessed the impact of various subsidy scenarios on net household income in 2021, which totaled 149.3 billion. Under an 80% subsidy scenario, net income slightly decreased to 148.3 billion. A 10% subsidy reduced net income to 145.8 billion. The findings suggested that reducing or eliminating fuel subsidies affects net household income, and prudent reinvestment in critical sectors is recommended to promote economic growth. Further analysis through hypothetical what-if scenarios is suggested to guide future policy decisions
A federated learning approach for Transformer-based classification of power grid disturbances
No full textSecuring smart grid systems against cyberattacks has become increasingly critical, especially as power grids grow more complex and interconnected. Cyberattack detection, however, is challenged by data privacy concerns and the decentralized nature of modern power systems. To tackle these issues, in this thesis, a federated learning framework combined with a Transformer Encoder-based model to effectively detect cyberattacks in power grids while preserving privacy is proposed. First, a federated learning setup is introduced allowing different Supervisory Control and Data Acquisition (SCADA) subsystems across power grid zones to train a common Transformer model collaboratively without sharing sensitive operational data. Next, a Transformer Encoder architecture is designed that accurately classifies power system behaviors into normal and attack scenarios using sensor and relay data. A comprehensive set of experiments demonstrate model's superior performance, yielding an accuracy of 97% and outperforming some of the traditional and deep learning approaches, including Deep Autoencoder (DAE), Convolutional Neural Network (CNN), and Long Short-Term Memory (LSTM) Network. The results highlight the effectiveness of Transformer-based federated frameworks in enhancing cybersecurity for decentralized power systems
The effects of course scheduling options on career technical education courses in the South Texas region
No full textThe efficacy of the CTE curriculum and program delivery can be affected by both internal and external factors. In an effort for community colleges to improve graduation and retention rates, institutions are developing enrollment and retention strategies that involve scheduling options. The purpose of this causal-comparative quantitative study was to investigate the effects of course scheduling on CTE programs in six South Texas community colleges during the 2020-2022 academic years. The effect of compressed scheduling options on student performance and course completion in CTE courses should be of particular interest to higher education leaders.
This study utilized the Kruskal-Wallis test to analyze statistical significance between CTE course performance and CTE course scheduling options of 4-week, 8-week and 16-week. The specific course performance indicators tested were CTE course student performance (grades) and CTE course completion. The relationship between student performance (grades) and course scheduling options was significant, X2 (2, N = 420) = 17.908, p <.001. Similarly, the relationship between CTE course completion and course scheduling options was significant, X2 (2, N = 420) = 9.708, p = .008. A 4-week and 8-week scheduling option provided a higher percentage of A and B letter grades when compared to a 16-week scheduling option. In terms of CTE course completion rates, a 4-week scheduling option had a 97% completion rate compared to an 86% completion rate when implementing a 16-week scheduling option.
The results of this quantitative study provide an understanding of the effects of scheduling options on CTE courses, specifically in South Texas community colleges. Furthermore, the results from this study will provide an insight into the efficacy of three different scheduling options. Findings from this study may be instrumental to institutional leaders as they contemplate incorporating a particular scheduling option that aligns with their strategy to increase the supply of a trained workforce
Effect of land use on variations of soil water availability in an agriculturally dense semi-arid region
No full textAccurate soil water (SW) storage information is essential to initialize weather and climate models, forecast crop yield, ensure effective water quantity/quality management, and conduct hydroclimatic prediction of floods and droughts. Land use plays a vital role in regulating spatiotemporal variations of SW availability (SWA) by influencing infiltration rates, runoff, and evapotranspiration, which are critical to crop productivity. This study investigated the relationships between SWA and land use/land cover (LULC) change in a semi-arid watershed, the Baffin Bay watershed, located in South Texas. The soil and water assessment tool (SWAT), a physical-based model widely used to simulate hydrologic processes, was employed. The major land-use types analyzed are shrubland, grassland, and cropland (i.e., corn, cotton, and sorghum). The model input data such as the land surface elevation, LULC, soil data, and climate data were obtained from various widely used sources. The model was calibrated and validated using monthly streamflow. The calibrated model was used as a baseline model to evaluate the spatial-temporal variations of SWA and to simulate various scenarios to examine the effects of LULC change on the SWA. Results indicate that the mean SWA of crop type is as follows in decreasing order sorghum > corn > cotton. Each crop responded similarly to precipitation, except for cotton from September 2015 through May 2018. Out of the crops, corn and sorghum had the highest correlation, followed by corn and cotton. Cotton and grassland had approximately the same correlation with the shrubland (RNGB). The LULC change scenarios simulations indicated that RNGB has an increased SWA compared to the grassland and agricultural land. Among the crop types considered, sorghum results displayed increased SWA, while cotton decreased the SWA. Urbanization had the most adverse effect on SWA. This research enhances the understanding of SWA in the study region and contribute to better agricultural management
A comparative study of the 21st century afterschool center on education in elementary schools in South Texas
No full textThis quantitative study examines the relationship between implementation of the 21st Century Afterschool Centers on Education (ACE) program and fourth grade student performance on the State of Texas Assessment of Academic Readiness (STAAR). Data collection was
extracted from schools within South Texas. The campus variation chosen for this study involved those implementing the ACE program as well as non-ACE campuses. Data was obtained through the 2018-2019 Texas Academic Performance Report (TAPR) published by Texas Education Agency (TEA) for each campus. This was completed to assess academic achievements in
Reading, Math and Writing on The State of Texas Assessments of Academic Readiness
(STAAR). The study applied a quantitative, ex-post facto research approach that analyzed data from fourth grade students enrolled in elementary schools in South Texas. Results of the study found no significant difference on STAAR performance between elementary schools which
implemented the ACE program and those which did not. Conclusions and implications are discussed as well as recommendations for future research
DNA demethylation mechanism in human cells
No full textDNA methylation plays a major role in the regulation of gene expression. It is primarily performed by one of three DNA methyltransferases. In contrast to DNA methylation,
demethylation is complicated and is not fully understood. Ten eleven translocase (TET) enzymes are believed to initiate active DNA demethylation by oxidizing 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Subsequently, the base excision repair (BER) system is believed to replace those intermediates to unmodified cytosines. However, it is believed that
some proteins involved in BER are DNA replication-dependent and are not expressed in postmitotic cells such as neurons. Therefore, it is not clear how postmitotic cells carry out DNA demethylation. In this study, our first aim was to analyze the expression of TET and BER proteins in neurons. For this, we analyzed cell type-specific expression of mRNAs and proteins using a large data set available from public database. As expected, some genes involved in DNA demethylation are not fully expressed in neurons in the human brain suggesting that human
neurons may have alternative mechanisms for DNA demethylation. Interestingly, we also observed that the expression of some demethylation genes is reduced in the human brain as age increases. Our second aim was to identify TET-interacting proteins. Because TET enzymes
cannot recognize specific sequence of DNA, they require other proteins such as coactivators to be localized to specific gene promoters for gene expression regulation. It is also possible that TET enzymes physically interact with other BER enzymes to carry out seamless DNA demethylation. For this, we constructed a human TET2 with a Twin-Strep Tag fusion for efficient pulldown and identification of TET2 complex proteins. In particular, we developed a Twin-Strep Tag cloning vector and also successfully amplified human TET2 cDNA by reverse
transcriptase (RT)-PCR for subsequent assembly into the protein expression construct
Characterization of GAP43-Gfp fusion protein in PC12 and NIH3T3 stable transfectant cells
No full textNerve regeneration is a physiological process in which damaged axons regrow after they have been injured. In the fully grown mammalian Central Nervous System (CNS), nerve regeneration is almost nonexistent. Researchers are conducting experiments and trying to
understand the mechanisms of nerve regeneration by manipulating neuronal cells at cellular and molecular levels to develop therapies for patients with nerve damage.
To study the mechanism of nerve regeneration, our laboratory has been focused on studying genes and proteins that are activated and expressed during and post axonal damage. Researchers had found that GAP-43, a protein with an apparent molecular weight of 43
kilodalton (kD) by electrophoresis, is overexpressed in axonal growth cones during neuronal development and nerve regeneration. Studies led researchers to understand that GAP-43 plays a key role in axonal regeneration, particularly in neurite growth and in axonal pathfinding. Our hypothesis is that sustained high level expression of the intrinsic protein GAP-43 enhances neuritogenesis and nerve regeneration. A plasmid encoding a chimeric protein in which the GAP-43 protein is fused with a fluorescent GFP molecule was used to express a GAP43-GFP
fusion protein, which allowed to detect and measure expression levels in transfected cells.
The plasmid with the recombinant hGAP43-tGFP gene expressing GAP43-GFP fusion protein was transfected into PC12 cells and stable transfectant cells were selected and grown in the laboratory. Over time, the stable transfectant cells expressing GAP43-GFP showed a significant loss of expression, which was observed through fluorescent microscopy and Western blot analysis. When comparing cells expressing GFP versus GAP43-GFP, the latter showed a much lower level of expression of the fluorescent protein. To understand better the rate of loss of
expression of GAP43-GFP, experiments were carried by transfecting PC12 and NIH3T3 cells and collecting cell lysates to conduct Western blot analysis of levels of expression