UARK (University of Arkansas )
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Morphology of Smallmouth Bass (Micropterus dolomieu) in Arkansas
No full textThe Smallmouth Bass, Micropterus dolomieu, is one of the most important game fishes in Arkansas. Three distinct lineages are recognized from different river basins: the Northern, Neosho, and Ouachita Smallmouth Bass. Understanding the biodiversity within this species complex inhabiting different water bodies in Arkansas is important for effective management of the fisheries resource and to guide conservation efforts. But current data on distribution of distinct forms are insufficient to guide management. The primary goals of the study presented here was to quantify morphological characteristics to identify distinct lineages of Smallmouth Bass, and to determine their specific locations within Arkansas streams and basins. Meristic counts of lateral line scales collected from 268 individual fish revealed significant differences among basins (Kruskal Wallace Rank Sum test H = 109.183, p \u3c 0.00001). These findings can be applied to identify and distinguish distinct lineages of Smallmouth Bass in Arkansas, and thus are important for guiding conservation strategies
Identifying Microbial Complexities and Control Strategies at Pre-Harvest Poultry Production
Get PDFWhile significant progress has been made in post-harvest control of Salmonella in the poultry industry, the development of effective pre-harvest intervention strategies remains critical for reducing foodborne pathogens. Environmental reservoirs such as poultry litter and drinking water systems (DWS) are potential harborage sites for Salmonella and other microbial communities. Understanding the microbiota of these environments, including biofilms within water lines, is essential to identifying factors contributing to Salmonella colonization and improving pre-harvest control approaches. This study aimed to evaluate the incidence and quantity of Salmonella in poultry litter and water lines, characterize the microbial populations in these environments, and assess the efficacy of various sanitizers against biofilm-forming pathogens in DWS. Samples were collected from 15 commercial conventional broiler farms, yielding 45 boot swabs from litter and 180 biofilm swabs from DWS. Microbial analyses included quantification of Salmonella, total aerobic bacterial count (APC), Enterobacteriaceae (EB), and yeast and molds (YM). The full-length 16S rRNA gene was amplified and sequenced to determine the microbial community composition. Results revealed a high Salmonella incidence of 95.6% (43 out of 45 houses) in litter samples, with an average load of 4.16 Log10 CFU/sample, compared to a lower incidence of 0.04% (8 out of 180 water lines) in biofilm samples, with an average load of 0.13 Log10 CFU/sample. Salmonella serogroups O7 (Salmonella Infantis) and O9 (Salmonella Enteritidis) were the most prevalent. Water quality significantly influenced microbial community composition, and distinct microbial profiles were observed between litter and biofilm samples, with only a few species in common. Furthermore, the antimicrobial efficacy of three sanitizers: peracid-based (PAB), peroxide-based (PB), and hypochlorite-based (HB) was evaluated against planktonic and biofilm cells of field-isolated Salmonella, Escherichia coli, and Bacillus species on polyvinylchloride (PVC), a common DWS pipe material. While all sanitizers were effective at reducing overall CFUs to varying extents, PAB demonstrated the greatest potential as a DWS sanitizer, showing superior efficacy against both planktonic and biofilm cells compared to PB and HB. This research highlights the importance of targeted microbial profiling and sanitizer efficacy testing for pre-harvest pathogen control, providing valuable insights for improving food safety in poultry production systems
Polyphenol-Protein Interactions in Pigmented Cereals – a Clean-Label Approach to Tailor Starch Viscosity
No full textViscosity plays an important role in the food industry as it affects the quality, processing stability, and shelf-life of food and impacts physiological responses such as satiation and satiety. Greater viscosity reduces food intake by increasing the perception of satiety, primarily by delaying gastric emptying and increasing tactile stimulation. Starch is commonly added to food products as a viscosifying ingredient, which often involves chemically modifying the starch via cross-linking, to enhance its resistance to high shear, temperature and acidity. However, chemically modified starches are not “clean-label” ingredients due to the use of toxic chemicals. Therefore, further exploration is needed to develop starch-based ingredients that are solely comprised of natural and chemical-free components while preserving the functional characteristics of chemically modified starch. Recent research demonstrated that polyphenols enhance starch viscosity by interacting with proteins, highlighting their role as natural cross-linkers. Pigmented cereals are a good source of polyphenols, which interact with endosperm proteins to affect the pasting and rheological properties of starch. Nevertheless, the nature and extent of their interactions, as affected by polyphenol and protein classes, are unknown. The present study aimed to elucidate the nature and extent of polyphenol-protein interactions and their role in the viscosity development of rice and sorghum of varying bran colors. The covalent and non-covalent nature of polyphenol-protein interactions in pigmented and non-pigmented rice and sorghum and their effects on pasting properties, were studied using chemical agents and at different pH environments. The changes in molecular weight and size, and the secondary and tertiary structures of proteins, as affected by polyphenol class and concentration, were monitored via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), high performance size-exclusion chromatography (HPSEC), circular dichroism spectroscopy (CD), and fluorescence spectroscopy, respectively. The viscosity development and protein structure were influenced by both polyphenol class and concentration. A low anthocyanin concentration in milled purple rice increased peak viscosity, and high anthocyanin levels in parboiled whole grain purple rice enhanced viscoelastic properties in an acidic environment due to the formation of covalent cross-links with glutelin. Black sorghum exhibited less breakdown in various pH environments as a result of hydrogen bonds and hydrophobic interactions between proanthocyanidins and prolamin. Polyphenol-protein interactions naturally enhanced and stabilized starch viscosity in both neutral and acidic environments, similar to chemically cross-linked starch, demonstrating their potential as clean-label ingredients with viscosifying and satiety-enhancing properties
In Search of Real Truth and Accurate History: Protecting and Resisting Whiteness in Education Policy Discourse
Get PDFThis research examines whiteness in education policymaking through a three-article dissertation, contributing to the broader understanding of how whiteness manifests across education policy and legislative discourse. The first article presents a comprehensive scoping review of critical whiteness studies (CWS) in education policy research. Using CWS tenets such as whiteness as property and colorblind racial ideologies, the analysis identifies themes of manipulated discourse, the economics of whiteness in education, and the protection of whiteness. This study anchors the second and third studies, which examine whiteness ideologies at play within the education policymaking discourse of the American Southeast. The second article addresses a knowledge gap by exploring state-level policymaking discourse, focusing on Tennessee’s anti-critical race theory (CRT) policy actions between 2021 and 2023. Guided by the research questions, this critical discourse analysis identifies the presence of whiteness ideologies throughout the policymaking process and is particularly embedded, while occasionally overlapping, in discourses of preservation, free expression, and urgency. The study also highlights the centrality of counternarratives through resistance discourse. The third article provides a comparative analysis of Tennessee and Arkansas to understand the role of whiteness ideologies in anti-CRT legislative discourse as a reflection of the broader moral panic in education conservatism. This comparison offers insight into the distinct expressions of whiteness ideologies regionally, the tenacity of resistance, and how these findings contribute to the national discourse within the anti-CRT movement. Several key findings emerge across the three articles. In each study, whiteness ideologies demonstrated a deep entanglement with education policy at all phases of the policymaking process. The particular shade of whiteness ideology shifts according to context and power relations, but the underlying need to protect whiteness by maintaining its invisibility remains a constant. In so doing, white supremacy maintains its hegemonic position in educational systems. Moreover, the unyielding resistance to these policy actions is active in both states and across education policy research. Lawmakers and stakeholders engage both direct and indirect strategies to challenge the whiteness ideologies in anti-CRT bills. This research contributes understanding to the intersection of education policy, legislative discourse, and critical whiteness studies by highlighting the importance of examining whiteness in education policy to illuminate and resist white supremacy in educational systems. While the battles continue to reshape and adopt new forms, the fight over curricular control and white-centric values continues across the Southeast and across the nation. The resistance continues
Meeting the Challenge: The Relationship Between Students’ Educational Gains and Teacher Full-Time Versus Part-Time Status
Get PDFThis study investigates the effect of instructor status—full-time versus part-time—on student Educational Functioning Levels (EFLs) in adult education centers across Arkansas from 2018 to 2023. Given that funding for these centers is directly tied to student performance, determining the most effective type of instructor is essential. The research examines programs like GED, English Language Learners (ELL), Integrated Education and Training (IET), and Workforce Alliance for Growth in the Economy (WAGE), addressing challenges such as a high number of adults without high school diplomas. Employing a regression model for analyzing EFL gains, the study seeks to provide actionable insights for hiring decisions and policy-making, enhancing educational outcomes and funding sustainability. The literature review suggests that full-time instructors may lead to better academic success due to their consistency and commitment, drawing on contemporary scholarly sources and grit theory. Methodologically, the study utilizes historical data through hierarchical regression analysis, with stratified random sampling ensuring representation. It uses secondary data from the LACES database for a robust quantitative basis, guiding educational administrators in optimizing staffing models. Despite geographic limitations, the study maintains ethical standards and offers insights into effective teaching strategies, influencing policy and resources distribution
Exploring Latent Mediation through Bayesian Regularization Methods of LASSO, Ridge, Horseshoe, Spike-and-Slab
Get PDFRegularization is a powerful tool to combat overfitting and drive sparsity in complex models. Regularization was initially applied in regression modeling but has been increasingly utilized in structural equation modeling where its utility in identifying the essential components has helped improve modeling. As structural equation models have increased in complexity both in the number of indicators but also the number of latent factors, researchers have begun to investigate how applying Bayesian regularization to these systems can further push the limits on modeling complex models with limited sample sizes. One area where research is limited is the application of Bayesian regularizations methods in models with multiple latent mediators. This study first seeks to investigate how the Bayesian regularization methods of ridge, LASSO, horseshoe, spike-and-slab, and spike-and-slab LASSO perform in capturing mediating variables of various strengths when examined under various sample sizes, number of possible mediators, and strength of latent factors. Secondly, an investigation into the sensitivity to prior settings was conducted on versions of Bayesian LASSO, Bayesian adaptive LASSO, horseshoe, and spike-and-slab. Finally, this study evaluated an empirical study investigating how these Bayesian regularization methods function with real data with multiple latent mediators
Effect of Beam Bracing on the Seismic Performance of Laterally Skewed Reduced Beam Section Moment Connections with Composite Concrete Slabs
Get PDFExisting experimental reduced beam section (RBS) moment frame investigations, particularly those used for prequalification in AISC-358, consider orthogonally oriented beam-to-column connections. While the design commentary provided in AISC-358 references recent skewed SMF numerical studies and potential performance effects when a lateral beam skew is introduced, limited experimental studies have been performed to verify the numerical findings. This study presents an experimental investigation into the cyclic behavior of RBS special moment frames that have lateral skew at the beam-to-column connection and composite concrete slabs. In this study, a skewed composite double-sided RBS connection is tested, having beam bracing outside the RBS connection to contrast observed behavior with recent testing neglecting RBS bracing, as is allowed when a slab is present. The test specimen in this study considers a W24x131 column and two W24x76 beams connected at a 15-degree lateral skew angle. Experimental results show that the connection retained 80% of its plastic moment capacity during 4% drift, meeting AISC-358 prequalification requirements. A beam top-flange fracture was observed at 6% drift due to ultra-low cycle fatigue resulting from the repeated local buckling of the beam flange. Moderate column twisting, and minimal column flange yielding at the acute skew angle side of the connection were observed. Inelastic deformation was successfully localized to the RBS region and there were no signs of the connection weld fractures. Comparing results with previous testing neglecting beam bracing, lateral beam bracing within d/2 from the RBS is recommended for connections having beam skews greater than 10 degrees, even if a composite concrete slab is present
An Instructional Remodel: How Adopting a Unifying Model-of-Instruction Impacted Teacher Self-Efficacy and Teacher Development and Evaluation Efforts in a Midwestern High School
Get PDFThis mixed methods study sought to determine the effect of adopting a unifying model-of-instruction on teacher self-efficacy and the development and evaluation processes of administrators. By assessing the level of teacher self-efficacy (Tschannen-Moran & Hoy, 2001) in the nascent stages of the instructional model’s implementation, then reassessing it after a multiple-month sequence of professional learning, the researcher provides a judgment on statistical significance concerning the two measurements and conjectures the extent to which the instructional model impacted any differences in self-efficacy levels. Using two separate “before and after” interviews with purposefully selected administrators, the researcher explored how the unification of instructional practice with a common framework for providing feedback impacted school leaders as they sought to develop teachers around a consistently defined paradigm in this model-of-instruction
Synthesis and X-ray Characterization of Nickel Phosphide Nanostructures for Water Oxidation
No full textThe pursuit of earth-abundant 3d transition metal catalysts for alkaline water electrolysis remains an active area of research. While NiFe layered double hydroxides (LDH) are currently the most active catalysts for the oxygen evolution reaction (OER), doping Ni-based catalysts with phosphorus to form Ni metal phosphides has emerged as a promising alternative. However, the complex crystalline and amorphous phases of NiPx have hindered their characterization, and the OER mechanism and origin of activity remain unclear. This dissertation aims to elucidate the synthesis, OER performance, and in situ reconstruction of amorphous NiPx-based nanomaterials, with a focus on in situ and ex situ X-ray characterization. Through a systematic investigation, we developed a synthetic route for uniform amorphous Ni70P30 nanoparticles, which served as a template for the formation of phase-pure Ni12P5, Ni2P, and Ni5P4 via temperature modulation. Using in situ X-ray absorption spectroscopy (XAS), we monitored the transformation of α-Ni(OH)2 and β-Ni(OH)2 during OER, revealing that β-Ni(OH)2 undergoes a potential-induced intercalation of anions to form a mixed α/β Ni(OH)2 phase. We also investigated amorphous NiPx with an oxidized α-Ni(OH)2 shell during OER, finding that the α-Ni(OH)2 shell protects the conductive NiPx core from structural reconstruction defects, promoting high OER performance. Furthermore, our study demonstrated that the NiPx-α-Ni(OH)2 core-shell nanoparticle promotes shorter Ni-O bonds at high anodic potentials, enhancing OER activity. We also developed a facile method for incorporating Fe and Co into amorphous Ni70P30 nanoparticles, resulting in uniform alloy and core-shell structures with improved OER activity. Notably, the addition of Co altered the OER mechanism, promoting lattice oxygen activation over the adsorbate evolution mechanism, although it was limited by irreversible inactivation of Co(IV) activation sites. This dissertation provides a fundamental understanding of synthesizing and monitoring OER activities of amorphous Ni-based phosphides, shedding light on their complex structure-activity relationships. The findings of this study have significant implications for the development of efficient and earth-abundant catalysts for alkaline water electrolysis