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Filtering Out the Dangers of Harmful Algal Blooms (2024)
Get PDFFiltering Out the Dangers of Harmful Algal Blooms
The 3MT (Three Minute Thesis) is a research communication competition that challenges students to communicate the significance of their projects without the use of props or industry jargon in just three minutes. The winner of the 3MT competition moves on to the Council of Southern Graduate School’s Regional Conference in March 2025.https://scholarworks.uark.edu/mtsturpc/1067/thumbnail.jp
A Volumetric Model of REE and Other Critical Element-Bearing Underclay Deposits in the Eckley Mine Area, Luzerne County, Pennsylvania
Get PDFThe Eastern Middle Anthracite Field in southern Luzerne County, Pennsylvania was investigated for potential quantities of critical minerals, including rare earth-bearing minerals (REE) present in underclay deposits associated with coal measures of an existing anthracite coal mine. This work is built on Department of Energy/National Energy Technology Laboratory (DOE/ NETL) 2016 work on samples from the Eckley Mine near Hazelton, Pa. which discovered elevated contents of some critical minerals in core from a single wellbore. This thesis reports on new and additional information collected from that area through geological field work, detailed conventional core descriptions, stratigraphic cross sections, and spectral gamma ray logging on five additional core samples. Detailed mapping and analyses of the data was performed using Geographic Information Systems (GIS) software to estimate the potential volume of a critical mineral-enriched underclay layer in the mine area. The interval of enriched underclay identified in cores and in outcrop, is estimated to be 10 feet thick. GIS software was utilized to extrapolate the areal extent of the underclay and determine its volume. These volume calculations were done by integrating historical surveyed mine benchmarks, lithologic logs, cross-sections, miner maps, geologic and topographic maps with modern geospatial data (LIDAR digital terrain data, digital topographic maps, and digital aerial images). Using both the historical and modern (geospatial) data, the estimated volume of critical mineral-enriched underclay with less than 100 feet of overburden was roughly 385-acre feet. Assuming an average bulk density of 2.85 g cm-3 for underclay, its total mass was calculated to be 1.47 million tons. Based on the 2016 NETL geochemistry, and by extrapolating the anomalous critical mineral zone to other wellbores that penetrated the target interval, the estimated total mass of critical minerals within the target zone is estimated at 3,720 tons and 6,200 tons at recovery rates of 30% and 50%, respectively. The recovery yield will be ultimately determined by the future method of mineral processing. This thesis provides an overall methodological template combining traditional geological analyses with GIS analytic tools that can be used to evaluate similar deposits in other coal basins
Photodegradation of Microplastics through Nanomaterials: Insights into Photocatalysts Modification and Detailed Mechanisms
Get PDFMicroplastics (MPs) pose a profound environmental challenge, impacting ecosystems and human health through mechanisms such as bioaccumulation and ecosystem contamination. While traditional water treatment methods can partially remove microplastics, their limitations highlight the need for innovative green approaches like photodegradation to ensure more effective and sustainable removal. This review explores the potential of nanomaterial-enhanced photocatalysts in addressing this issue. Utilizing their unique properties like large surface area and tunable bandgap, nanomaterials significantly improve degradation efficiency. Different strategies for photocatalyst modification to improve photocatalytic performance are thoroughly summarized, with a particular emphasis on element doping and heterojunction construction. Furthermore, this review thoroughly summarizes the possible fundamental mechanisms driving the photodegradation of microplastics facilitated by nanomaterials, with a focus on processes like free radical formation and singlet oxygen oxidation. This review not only synthesizes critical findings from existing studies but also identifies gaps in the current research landscape, suggesting that further development of these photocatalytic techniques could lead to substantial advancements in environmental remediation practices. By delineating these novel approaches and their mechanisms, this work underscores the significant environmental implications and contributes to the ongoing development of sustainable solutions to mitigate microplastic pollution
Does Private School Choice Threaten Democracy? Evidence from Private and Public Schools in New York City and Dallas/Fort Worth
Get PDFA major concern in the ongoing debate over school choice is whether private schools help to increase their students’ levels of tolerance necessary for a functioning democracy in the United States. Over 40 years ago, scholars at the University of Minnesota created a survey which measured political knowledge, political tolerance, perceived threats from opposing groups, and support for democratic norms anchored in each respondent’s view of the political group they find most distasteful. In 1997, researchers at various universities used a similar survey instrument to derive responses from students in eighth-grade social studies classes who were enrolled in seven public and twenty-four private schools in New York City and Dallas/Fort Worth, Texas. Those original data remained archived and unexamined for decades. We analyze those data using Ordinary Least Squares (OLS) and rigorous Nearest Neighbor Matching (NNM) methods based on propensity scores. We find that students who attended private schools demonstrate higher levels of political knowledge and stronger support for democratic norms when compared to observationally similar students who attended public schools
Modeling, Characterization, and Machine Learning Algorithm for Rectangular Choke Horn Antennas
Get PDFIn this work, we present the design and modeling of a new type of choke horn antenna. It incorporates a rectangular waveguide and a rectangular choke acting as a parasitic element. The four-sided geometry of the antenna is applicable to systems that utilize rectangular waveguides. Also, it can overcome the need for rectangular-to-circular transition of transmission line or mode conversion. The main objective of this paper is to develop a model that calculates the far field radiation characteristics of the proposed antenna (analytical part) and to incorporate a finite element method (FEM) solver that adds to the theoretical solution (empirical part), which finally leads to obtaining a hybrid model. The omnidirectional radiation property of the choke is demonstrated, which gives an insight into the influence of this parasitic element on the total radiated power. The same observations made on the rectangular choke can be translated to the circular choke as well. At an operating frequency of 2.45 GHz, the design is numerically and experimentally validated. Also, the demonstrated hybrid model can leverage the integration of supervised machine learning (ML) models by exporting radiation variables such as gain and half-power beamwidth (HPBW) and performing predictions based on the training data from the model. Therefore, we incorporate gradient boosting and neural network ML algorithms, which are tailored to the desired radiation pattern parameters
Evaluation of Fall and Winter Trinexapac-ethyl Applications on Ultradwarf Bermudagrass Putting Green Color, Quality, and Green Cover
Get PDFUltradwarf bermudagrass (UDB) putting greens grown in subtropical and temperate climates can face elevated risk of winter injury from cold temperatures. Trinexapac-ethyl (TE) inhibits UDB growth potentially reducing spring green-up and overexertion of carbohydrate reserves for UDB during the cold de-acclimation period. A field study was conducted to determine the effect of fall and winter TE applications on the visual quality and color of UDB putting greens in Virginia from the cold acclimation phase through the cold de-acclimation phase. A second controlled-environment study was conducted to determine how TE applications to UDB during cold acclimation affected UDB cold tolerance. In the first study, plots were treated with 0.026 kg⋅ha−1 a.i. every 14 days, 0.013 kg⋅ha−1 a.i. every 14 days, or 0.013 kg⋅ha−1 a.i. every 7 days either in the fall only or in the fall and winter. A nontreated control was included for comparison. For the second study, cup-cutter plugs (10.8-cm diameter) of UDB were treated with 0.026 kg⋅ha−1 a.i. every 14 days from the time growth resumed after green-up through cold acclimation or not treated with TE. Plugs were then exposed to −9.4 °C for 4, 6, 8, or 10 hours and placed into a greenhouse to green up. The GC50 values (exposure time to reduce bermudagrass green cover by 50% 6 days after exposure to −9.4 °C) for the treatments were then calculated based on exposure time and percent green-up. In the first study, TE applications improved UDB quality \u3e3.8%. However, TE applications reduced UDB color, and trends exhibited this reduction in color particularly during the late cold acclimation, winter dormancy, and early cold de-acclimation phases. In the second study, TE applications reduced GC50 values by \u3e10.9% compared with nontreated plugs, suggesting TE reduces UDB cold tolerance during the cold acclimation phase
High-Quality Single-Step Growth of GaAs on C-Plane Sapphire by Molecular Beam
Get PDFWe report on the growth of high-quality GaAs semiconductor materials on an AlAs/sapphire substrate by molecular beam epitaxy. The growth of GaAs on sapphire centers on a new single-step growth technique that produces higher-quality material than a previously reported multi-step growth method. Omega-2theta scans confirmed the GaAs (111) orientation. Samples grown at 700 °C displayed the highest crystal quality with minimal defects and strain, evidenced by narrow FWHM values of the rocking curve. By varying the As/Ga flux ratio and the growth temperature, we significantly improved the quality of the GaAs layer on sapphire, as compared to that obtained in multi-step studies. Photoluminescence measurements at room temperature and 77 K further support these findings. This study underscores the critical role of the As/Ga flux ratio and growth temperature in optimizing GaAs epitaxial growth on sapphire
Assessment of the Impact of Humic Acids on Intestinal Microbiota, Gut Integrity, Ileum Morphometry, and Cellular Immunity of Turkey Poults Fed an Aflatoxin B\u3csub\u3e1\u3c/sub\u3e-Contaminated Diet
Get PDFA recent study published data on the growth performance, relative weights of the organs of the gastrointestinal tract, liver histology, serum biochemistry, and hematological parameters for turkey poults fed an experimental diet contaminated with aflatoxin B1 (AFB1) and humic acids (HA) extracted from vermicompost. The negative effects of AFB1 (250 ng AFB1/g of feed) were significantly reduced by HA supplementation (0.25% w/w), suggesting that HA might be utilized to ameliorate the negative impact of AFB1 from contaminated diets. The present study shows the results of the remaining variables, as an extension of a previously published work which aimed to evaluate the impact of HA on the intestinal microbiota, gut integrity, ileum morphometry, and cellular immunity of turkey poults fed an AFB1-contaminated diet. For this objective, five equal groups of 1-day-old female Nicholas-700 turkey poults were randomly assigned to the following treatments: negative control (basal diet), positive control (basal diet + 250 ng AFB1/g), HA (basal diet + 0.25% HA), HA + AFB1 (basal diet + 0.25% HA + 250 ng AFB1/g), and Zeolite (basal diet + 0.25% zeolite + 250 ng AFB1/g). In the experiment, seven replicates of ten poults each were used per treatment (n = 70). In general, HA supplementation with or without the presence of AFB1 showed a significant increase (p \u3c 0.05) in the number of beneficial butyric acid producers, ileum villi height, and ileum total area, and a significant reduction in serum levels of fluorescein isothiocyanate–dextran (FITC-d), a marker of intestinal integrity. In contrast, poults fed with AFB1 showed a significant increase in Proteobacteria and lower numbers of beneficial bacteria, clearly suggesting gut dysbacteriosis. Moreover, poults supplemented with AFB1 displayed the lowest morphometric parameters and the highest intestinal permeability. Furthermore, poults in the negative and positive control treatments had the lowest cutaneous basophil hypersensitivity response. These findings suggest that HA supplementation enhanced intestinal integrity (shape and permeability), cellular immune response, and healthier gut microbiota composition, even in the presence of dietary exposure to AFB1. These results complement those of the previously published study, suggesting that HA may be a viable dietary intervention to improve gut health and immunity in turkey poults during aflatoxicosis
Remote, Rugged Field Scenarios for Archaeology and the Field Sciences: Object Avoidance and 3D Flight Planning with sUAS Photogrammetry
Get PDFAdvances built into recent sUASs (drones) offer a compelling possibility for field-based data collection in logistically challenging and GPS-denied environments. sUASs-based photogrammetry generates 3D models of features and landscapes, used extensively in archaeology as well as other field sciences. Until recently, navigation has been limited by the expertise of the pilot, as objects, like trees, and vertical or complex environments, such as cliffs, create significant risks to successful documentation. This article assesses sUASs’ capability for autonomous obstacle avoidance and 3D flight planning using data collection scenarios carried out in Black Mesa, Oklahoma. Imagery processed using commercial software confirmed that the collected data can build photogrammetric models suitable for general archaeological documentation. The results demonstrate that new capabilities in drones may open up new field environments previously considered inaccessible, too risky, or costly for fieldwork, especially for all but the most expert pilots. Emerging technologies for drone-based photogrammetry, such as the Skydio 2+ considered here, place remote, rugged terrain within reach of many archaeological research units in terms of commercial options and cost
Valuing Trans Lives After Suicide: Rituals of Commemoration in Digital Social Media Culture
Get PDFIn 2014, a trans teenager named Leelah Alcorn posted a suicide letter to her public Tumblr account. Almost a decade later, in 2023, Eden Knight, another young trans woman, posted a suicide letter to her public Twitter account. Both suicide letters went viral and inspired memorial hashtags on the platforms where they initially circulated. In this article, I identify similarities between the cases, conceptualizing both as rituals of commemoration aimed toward restoring value to trans lives lost too soon. My analysis shows how ordinary users leverage the connective affordances embedded within popular social media platforms to sustain structured, value-laden acts of remembrance and mourning. In doing so, I elucidate four stages of the ritual process: (1) sharing suicide letters, (2) enshrining selfies, (3) modulating memories, and (4) casting blame. Ultimately, I argue that trans-led rituals of commemoration can function as justice-oriented tactics of resistance against engrained systems of oppression that perpetuate disproportionally high rates of early death within trans communities