Texas A&M University-Kingsville: AKM Digital Repository
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Apparent permeability of liquid rich shales
No full textThe goal of this research is to present a new formulation expressing the apparent permeability of liquid rich shale strata based on pressure driven flow. Apparent permeability is important for the accurate prediction of production rates.
For the first time we introduce an apparent permeability formulation to predict the volumetric flux of oil in liquid rich shale formations. Nanopores associated with the structure of shale formations introduce molecular slippage on the pore walls and break down the continuum no-slip flow assumption. The molecular slippage on the pore walls makes Darcy’s permeability inappropriate to determine the volumetric flux of oil in shale formations.
In this research, a correction to the slippage phenomenon is made to properly model fluid flow in shale oil strata. The proposed permeability expression is validated with an existing set of experimental data.
The derived formulation in this study shows that the apparent permeability of liquid rich shales increases with increased slip length; the slip length is defined as an extrapolated distance relative to the nanopore wall where the tangential velocity component vanishes. This novel permeability formulation is expressed in a compatible form with Darcy’s equation for ease of use in reservoir simulators. The results suggest that the proposed apparent permeability term provides a better prediction of oil volumetric flux compared to that given by the simple Darcy’s permeability
Promoter region analysis of gRICH70 gene, a gene induced during nerve regeneration
No full textMammals, even while including very advanced organisms, have lost some abilities during evolution. One such ability is the regeneration of nerves in the Central Nervous System (CNS). Cold blooded vertebrates like the teleost fish (goldfish and zebrafish) have the ability to regenerate axons in their CNS. The regeneration of the optic nerve in teleost fish is used as a model of CNS nerve regeneration. Upon optic nerve crush, there are changes in gene expression that are followed by sturdy optic axon regeneration. One such gene which is highly expressed is gRICH70 (Regeneration Induced CNPase Homolog of 70 kDa). A web based Neural Network Promoter Prediction (NNPP) software package allowed the prediction of the TATA box and transcriptional start site of the gene. A 1.5 kbp fragment including 1.3 kbp of the upstream region and the first exon of the gene showed high promoter activity in both PC12 and NIH3T3 cell lines.
Analyzing in further detail the promoter region of gRICH70 was the main objective of this research project. A 0.42kbp sub-fragment containing the first exon and a small portion of upstream region was obtained by restriction digestion and sub-cloned into the luciferase reporter plasmid pGL3 basic. The construct was transfected into both PC12 and NIH3T3 cells and tested for promoter activity by luciferase assays. Web based software packages like NSITE and Softberry USA predicted a few putative regulatory elements in the 0.42kbp fragment. A further objective of this project was the mutation of predicted elements in the 0.42kbp fragment by PCR mutagenesis and then testing their effect in promoter activity. Primers were designed and used to amplify the desired mutated fragments through PCR. These fragments were purified, sub-cloned into pGL3 plasmid and the constructs were tested for promoter activity. Based on the results obtained, the 0.42kbp fragment was further sub-divided into smaller fragments that were tested for promoter activity. The analysis has allowed the identification of key regions and elements of the gene that regulate gene expression in different cell types
The effect of citrus flush stage in the distribution of trunk injected oxytetracycline for HLB management
No full textHuanglongbing (HLB) or citrus greening, is one of the world’s most devastating and threatening citrus diseases. The causal agent is the phloem-limited bacteria ‘Candidatus Liberibacter asiaticus’ (CLas). Several studies have addressed the effect of oxytetracycline (OTC) applications on CLas titers under different conditions, from delivery methods to seasonal effects. However, there is limited information on how the vegetative growth cycle affects OTC distribution on the tree to target CLas populations. In this field study, OTC concentrations were measured in CLas positive grapefruit trees by LC/MS and CLas titers were assessed by qPCR in flushing and non-flushing branches after injecting 2.0 g of OTC in the trunk. Three trees injected with water were used as controls. Leaf samples were collected at 4 locations along flushing and non-flushing branches from the same trees after 0-, 4-, 8-, 16-, 32-, and 180-days post-treatment. Results indicate a significant difference in CLas titers between the OTC treated and control trees. We detected OTC residues in both flushing and non-flushing branches after 4 days post-injection. However, OTC was unevenly distributed overtime along the tree branches, and lower levels of residues were detected in flushing branches compared to non-flushing branches. Moreover, CLas titers were reduced at the same level in both, flushing and non-flushing branches, indicating that OTC worked regardless if the flushing stage if the branches or the tree. This study helps understand the translocation of therapeutic compounds within the tree for effective management against HLB
Examining the culturally responsive teaching self efficacy of inservice monolingual and bilingual teachers in rural Southeast Texas
No full textAs achievement gaps for emergent bilingual students (EBS) persist, teachers in rural Southeast Texas school districts face increasing demands to meet the needs of a culturally and linguistically diverse (CLD) student population. However, research suggests that teachers may need support developing the self-efficacy necessary to effectively implement culturally responsive teaching practices in the classroom. Cruz et al. (2019) found that “little research has examined the extent to which teachers feel competent specifically in their ability to implement culturally responsive teaching (CRT) practices” (p.3). Although existing research has explored teacher self-efficacy in other contexts, a dearth of research has examined whether in-service monolingual and bilingual teachers in dual language contexts possess the culturally responsive teaching self-efficacy necessary to meet the needs of EBS.
Using survey responses, this study examined the culturally responsive teaching self efficacy (CRTSE) of monolingual and bilingual teachers (N=55) in a one-way dual language immersion model. Guided by Bandura’s (1977) theory of self-efficacy and Gay’s (2002) culturally responsive teaching framework, this explanatory sequential mixed methods study utilizes quantitative survey data to examine monolingual and bilingual teachers’ CRTSE (as measured by Siwatu’s CRTSE scale), followed by qualitative semi-structured interviews to explore teacher perceptions and barriers towards the implementation of CRT in a one-way dual language model. This study addresses a gap by examining the culturally responsive teaching self efficacy (CRTSE) beliefs, perceptions, and barriers to CRT implementation of monolingual and bilingual teachers in a one-way dual language immersion model.
While the findings indicate a slight trend toward higher self-efficacy among bilingual teachers, the difference between monolingual (86.64) and bilingual teachers (89.36) was nominal. Moreover, the results show that the difference between the CRTSE scores was not statistically significant, suggesting that language background alone does not have an impact on CRTSE. Insights from the semi-structured interviews revealed that teachers perceive CRT as transformational, multidimensional, validating, and a means for promoting social justice in the classroom. The findings underscore the need for more in-depth examination of the culturally responsive teaching self-efficacy of in-service monolingual and bilingual teachers serving emergent bilingual students in rural communities. These findings offer valuable insight into how CRTSE shapes the instructional practices of monolingual and bilingual teachers within a dual language context, emphasizing the need for targeted teacher support to close achievement gaps among emergent bilingual students
Athletic directors' perceptions dealing with gender equity in Texas high school athletics
No full textThe struggle for equality between men and women has been an ongoing battle for centuries. From the seventeenth century to the present, women have made significant strides toward gender equity. Laws and regulations have continued to bridge the gap between men and women with the signing of Title IX (Title IX, 2015). Title IX is a federal law designed to close the gender gap in programs receiving federal funds, which includes education and sports programs. Even after enactment of Title IX, a problem continues to exist in high school athletic programs, a problem indicating the presence of gender inequality. Yet, the athletic directors and districts participating in the study understood the main perceptions of Title IX. There were five major themes that emerged from the study: responsibilities, budget, hiring of coaches, compliance and barriers in Title IX. The themes emerged consistently throughout the interviews, showing commonality between the districts involved. The study was important in identifying and offering strategies to enable a better understanding of the perceptions of athletic directors regarding issues related to Title IX as it pertains to athletic programs in the Region 2 educational service area of South Texas. Additionally, the perceptions of barriers which may prevent high schools from complying with Title IX were investigated
Evaluation of grassland restoration techniques and seed mix development for use on new solar developments in South Texas
No full textRenewable energy efforts across the country have grown significantly over the last decade. The objective of this project was to determine how to restore height-appropriate native grassland communities within utility-scale solar developments. The effects of planting date, planting technique, seed mix diversity, and sampling height on plant functional groups were evaluated during the active construction of a utility-scale solar development in Bee County, Texas. An 8-ha research area was used to test the planting of three seed mixes: low-diversity (4 species), mid-diversity (11 species), and high-diversity (19 species), planted using both drill and hydroseeding techniques during both pre- and post-installation of the solar development. I found that grassland restoration plantings influenced the percent cover of native plant species at the 5-cm sampling height (F 6, 121 = 2.58, P = 0.0021). The cover of seeded species was greatest at the low- and mid-diversity plantings when compared to the high-diversity, suggesting that additional diversity does not increase the percent cover of seeded species (F 6, 68.7 = 2.16, P = 0.0569). An inverse relationship was observed between sampling height and species cover. The same result was also observed in the analysis of species richness. This means that grassland restoration plantings can be used to effectively increase native vegetation cover on utility-scale solar developments in Bee County, Texas, by choosing seed mixes with 4-11 species that are quick to establish within one year. However, because my seed mixes with higher diversity also included species with a broader range of functional characteristics as well as some species that were less adapted to my study area, it cannot be determined whether the richness effects I recorded were attributable to effects of species richness, functional characteristics, or unequal species adaptability at the study site
Examining the relation between TELPAS scores and student achievement on the eighth-grade science STAAR test for students with limited English proficiency
No full textThis study explores the relationship between English Learners (ELs) in the Texas school system and their outcomes on the State of Texas Assessments of Academic Readiness (STAAR) tests and the Texas English Language Proficiency Assessment System (TELPAS). Schumann’s Acculturation Model and Krashen’s Input Hypothesis were used as theoretical groundwork to provide a thorough framework for exploring this association.
To determine the different levels of acculturation among ELs, this study addressed the research questions posed using quantitative correlational research, specifically, the quantitative data of TELPAS and STAAR from a South Texas school district. The goal of this inquiry recognized patterns and trends within the data to determine if a substantial association exists between TELPAS scores and STAAR outcomes among ELs attending Texas schools.
The study regularly found a modestly positive correlation between TELPAS scores and 8th-grade science STAAR scores. The results were statistically significant in all years, demonstrating a favorable association between a higher degree of English language proficiency and enhanced academic performance in the subject of science. Future research should investigate potential relationships and practical applications to develop effective techniques for assisting ELs. These observations can guide educational methods and regulations, ultimately enhancing student achievements and fostering fairness in education. These findings can guide instructional practices, resource allocation, and support systems for ELs. Furthermore, Schumann's Acculturation Model and Krashen's Input Hypothesis adds to the continuing conversation about language acquisition in diverse educational contexts by providing a new angle on the variables influencing ELs' academic success and language proficiency
Exploring the nexus of faculty motivation and funding opportunities : a phenomenological study of HSI external grant pursuits
No full textThe education systems are in a state of transformation and unpredictable change (i.e., policy reforms, technological advancement, change in education, and higher education funding). Like many other aspects, there are numerous moving parts when focusing on external funding at higher education institutions. The study provided an overview using qualitative methodology to understand an emerging research topic. This qualitative study explored new faculty perceptions and motivators to secure Hispanic-Serving Institutions (HSI) external funding at a selected South Texas System School. The questions for this study were: how do new faculty at Hispanic-Serving Institutions (HSIs) view their experiences with external funding opportunities? What are the motivators of new faculty regarding HSI external funding? What challenges do new faculty members face regarding HSI external funding? The results from this study were vital since faculty perceptions were influenced by their experiences. Utilizing a phenomenological approach, the researcher provided an online questionnaire and volunteer interviews for new faculty members from one Hispanic Serving Institution (HSI). For the questionnaires, the sample size was up to 90 participants. For the interviews, a maximum of 15 participants were included in this qualitative study. The problem is the lack of motivation for external funding, resulting in unclaimed funds, frustration, and under-sourced learning. The study aimed to understand new faculty's perspectives on effective practices for increasing external funding. It also sought to identify their motivators and challenges in pursuing HSI funding opportunities
Exploring bilingual elementary teachers' perceptions regarding STEM education teaching practices in the Mexican context
No full textIn the last decades, an interdisciplinary approach to teaching science, technology, engineering, and mathematics (STEM) that aims to engage K-12 students in a multidisciplinary manner has been implemented in different countries (Sias et al., 2017). Although research about elementary teachers' perceptions about STEM education and STEM teaching practices has been conducted in other countries, little research has been done in Northern Mexico to explore bilingual elementary teachers' perceptions about STEM education and STEM teaching practices in the private sector. Thus, this mixed-method study utilized an explanatory sequential design to investigate bilingual elementary teachers' perceptions about STEM education and STEM teaching practices. In phase one of the study, 83 bilingual teachers' quantitative data were gathered through an online survey. Six bilingual teachers were interviewed in phase two to collect qualitative data to explain in-depth quantitative results. In the qualitative phase one, it was found that the majority of participants perceived their preparation for STEM education as positive. Bivariate correlational analysis between participants' (a) years of teaching experience, (b) grade level taught, (c) highest level of education completed, and participants' perceptions on their preparation to teach STEM and their perceptions about STEM teaching practices effectiveness showed a little correlation between variables, that was not statistically significant. It was also found that the majority of participants positively perceived STEM teaching practices' effectiveness. In qualitative phase two, it was found that the majority of participants could identify teaching practices promoted by STEM education; however, only two participants could describe teaching practices clearly. Furthermore, qualitative data expanded on participants' quantitative responses about the type of preparation in STEM education they received and about participants' perceptions about STEM teaching practices' effectiveness. Implications and recommendations for future research about STEM education are presented
Dynamics and resiliency of networks with concurrent cascading failure and self-healing
No full textLocal attacks in networked systems can often propagate and trigger cascading failures. Designing effective healing mechanisms to counter cascading failures is critical to enhance system resiliency. A general modeling and simulation framework is developed in this work to quantitatively evaluate the resilience of networked systems under two types of failures: connectivity and load-based. Two newly designed dynamic healing mechanisms are demonstrated. The model considers concurrent cascading failure and healing processes on networks. A general discrete-time simulation (i.e., number of failed nodes at each time step) framework is developed to advance understanding of the dynamics of networks with concurrent cascading failure and self-healing. The resiliency is evaluated using various metrics, i.e., the recovery level, the average damage impact and the recovery time. Those metrics are used to evaluate and compare the healing performance. Based on several real-world networks models, the dependence of system trajectories and resilience metric on various model parameters is explored. If the triggering level (fraction of inactive nodes when healing starts) is too high, the system would either undergo a very slow recovery or never recover to a satisfactory level at all. However, this work provides a counter example to the intuition that the smaller the triggering level, the shorter the recovery time. While low budgets (number of nodes allowed to recover at each time step) lead to prolonged or unsuccessful recovery, it appears that the resilience metric converges to a limit when budget is raised to high enough. This may have practical implications, as node recovery requires resources and a budget too high or too low would be wasteful. It is also found that two parameters (reactivated node load parameter and node healing certainty level) span a phase plane for network dynamics where three regimes exist. To ensure full network recovery, the two parameters need to be moderate. Lastly, in this work, we study the possible linkage between robustness and resilience by finding the correlation between the two quantities. A resilient networked system is not necessarily robust, and vice versa. This works lays the foundation for subsequent studies on more complex mechanisms and processes on the networks, optimization of model parameters for maximum resilience, as well as applications to more real-world network models and scenarios