University of Arkansas
  • Fayetteville, AR, United States
Recent publications
Image processing in amniotes is usually accomplished by the thalamofugal and/or tectofugal visual systems. In laterally eyed birds, the tectofugal system dominates with functions such as color and motion processing, spatial orientation, stimulus identification, and localization. This makes it a critical system for complex avian behavior. Here, the brains of chicks, Gallus gallus , were used to produce serial brain sections in either coronal, sagittal, or horizontal planes and stained with either Nissl and Gallyas silver myelin or Luxol fast blue stain and cresyl echt violet (CEV). The emerging techniques of diffusible iodine‐based contrast‐enhanced computed tomography (diceCT) coupled with serial histochemistry in three planes were used to generate a comprehensive three‐dimensional (3D) model of the avian tectofugal visual system. This enabled the 3D reconstruction of tectofugal circuits, including the three primary neuronal projections. Specifically, major components of the system included four regions of the retina, layers of the optic tectum, subdivisions of the nucleus rotundus in the thalamus, the entopallium in the forebrain, and supplementary components connecting into or out of this major avian visual sensory system. The resulting 3D model enabled a better understanding of the structural components and connectivity of this complex system by providing a complete spatial organization that occupied several distinct brain regions. We demonstrate how pairing diceCT with traditional histochemistry is an effective means to improve the understanding of, and thereby should generate insights into, anatomical and functional properties of complicated neural pathways, and we recommend this approach to clarify enigmatic properties of these pathways.
The escalating threat of natural disasters to public safety worldwide underlines the crucial role of effective environmental risk management tools, such as insurance. This is particularly evident in the case of earthquakes that occurred in Oklahoma between 2011 and 2020, which were linked to wastewater injection, underscoring the need for earthquake insurance. In this regard, from a survey of 812 respondents in Oklahoma, USA, we used supervised machine learning techniques (i.e., logit, ridge, least absolute shrinkage and selection operator (LASSO), decision tree, and random forest classifiers) to identify the factors that influence earthquake insurance uptake and to predict individuals who would acquire earthquake insurance. Our findings reveal that influential factors that affect earthquake insurance uptake include demographic factors such as older age, male gender, race, and ethnicity. These were found to significantly influence the decision to purchase earthquake insurance. Additionally, individuals residing in rental properties were less likely to purchase earthquake insurance, while longer residency in Oklahoma had a positive influence. Past experience of earthquakes was also found to positively influence the decision to purchase earthquake insurance. Both decision trees and random forests demonstrated good predictive capabilities for identifying earthquake insurance uptake. Notably, random forests exhibited higher precision and robustness, emerging as an encouraging choice for earthquake insurance modeling and other classification problems. Empirically, we highlight the importance of insurance as an environmental risk management tool and emphasize the need for awareness and education on earthquake insurance as well as the use of supervised machine learning algorithms for classification problems.
X-ray appearance of normal galaxies is mainly determined by X-ray binaries powered by accretion onto a neutron star or a stellar mass black hole. Their populations scale with the star-formation rate and stellar mass of the host galaxy, and their X-ray luminosity distributions show a significant split between star-forming and passive galaxies, both facts being consequences of the dichotomy between high- and low-mass X-ray binaries. Metallicity, IMF and stellar age dependencies, and dynamical formation channels add complexity to this picture. The numbers of high-mass X-ray binaries observed in star-forming galaxies indicate quite high probability for a massive star to become an accretion-powered X-ray source once upon its lifetime. This explains the unexpectedly high contribution of X-ray binaries to the cosmic X-ray background, of the order of ∼10%, mostly via X-ray emission of faint star-forming galaxies located at moderate redshifts which may account for the unresolved part of the CXB. Cosmological evolution of the LX −SFR relation can make high-mass X-ray binaries a potentially significant factor in (pre)heating of intergalactic medium in the early Universe.
While lithium-ion batteries (LIBs) are approaching their energy limits, lithium metal batteries (LMBs) are undergoing intensive investigation for higher energy density. Coupling LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode with lithium (Li) metal anode, the resultant Li||NMC811 LMBs are among the most promising technologies for future transportation electrification, which have the potential to realize an energy density two times higher than that of state-of-the-art LIBs. To maximize their energy density, the Li||NMC811 LMBs are preferred to have their cathode loading as high as possible while their Li anode as thin as possible. To this end, we investigated the effects of different cathode active material loadings (2 – 14 mg/cm2) on the performance of the Li||NMC811 LMBs. Our study revealed that the cathode loadings have remarkably affected the cell performance, in terms of capacity retention and sustainable capacity. Cells with high cathode loadings are more liable to fade in capacity, due to severer formation of the CEI and more sluggish ion transport. In this study, we also verified that the protection of the Li anode is significant for achieving better cell performance. In this regard, our newly developed Li-containing glycerol (LiGL) via molecular layer deposition (MLD) is promising to help boost the cell performance, which was controllably deposited on the Li anode.
Magnetic Resonance Imaging (MRI) is typically a slow process because of its sequential data acquisition. To speed up this process, MR acquisition is often accelerated by undersampling k-space signals and solving an ill-posed problem through a constrained optimization process. While traditional methods use image priors as constraints, modern deep learning methods use supervised learning with ground truth images to learn image features and priors. However, in some cases, ground truth images are not available, making supervised learning impractical. To address this issue, we propose an unsupervised deep learning framework for accelerated MRI that does not require ground truth images for training. Our framework combines a system prior derived from the MR acquisition model with generic image priors to build a more effective unsupervised deep learning framework. The system prior enforces data consistency while the generic image priors regulate the neural network parameters. Our experimental results demonstrate that our proposed unsupervised method outperforms state-of-the-art unsupervised methods and achieves performance comparable to that of supervised methods that require ground truth images for training.
The present study explored the role race-related barriers and practical barriers to treatment participation play in treatment effectiveness and satisfaction among Black families with autistic youth using a mixed-method approach. In a sample of Black caregivers with autistic youth (N = 101), multiple regressions were conducted to examine the impact of reported racial and practical barriers on parental stress, treatment effectiveness, and treatment satisfaction. Caregivers provided further narratives on their experience navigating diagnostic and treatment services in qualitative interviews. The study demonstrated that Black caregivers of autistic youth are still encountering several racial and logistical barriers when seeking treatment and diagnostic services for their children. These barriers negatively impact caregiver stress and caregiver perceived treatment quality. Contrary to the barriers and stress experienced by Black caregivers, caregivers are generally satisfied with the treatments they are utilizing and find them helpful. The narratives told by caregivers further elucidate the tumultuous experiences of Black caregivers as they seek diagnostic and treatment services for their children. An experience that may be worsened by family, professional, and systemic barriers, and can be improved by advocacy, acceptance, peer and community support, and increased knowledge. Black families of autistic youth call for increased compassion, support, training, and humility among professionals who serve autistic youth.
We examine consequences of climate-induced range expansion on community composition and diversity within trees attacked by the southern pine beetle (Dendroctonus frontalis Zimmermann). At the northernmost limit of the southern pine beetle range where populations have persisted for multiple years (currently Long Island, NY), we collected and reared bark samples and placed emergence traps on southern pine beetle-attacked pitch pine, Pinus rigida Mill. (Pinales: Pinaceae). From these samples, we quantified southern pine beetle gallery length and emergence as well as the diversity and abundance of all associated insects including known and suspected competitors, predators, and parasitoids. We compared our results to that of historic sampling data (1975–1997) in the core of southern pine beetle’s range in the southern United States. Key community members were present in both the northern and southern regions; composition and relative abundances differed markedly. A key predator, the clerid beetle Thanasimus dubius (Fabricius) (Coleoptera: Cleridae), was present in similar densities in both regions. Southern pine beetle infested a greater proportion of the length of the tree bole in the North. This increased tree utilization may be a consequence of a lack of resource competition by Ips De Geer (Coleoptera: Curculionidae) engraver beetles, which we found only in very low abundance in the northern sites. We discuss the implications of these results in the context of southern pine beetle range expansion. Continued study of the southern pine beetle community and temporal southern pine beetle dynamics in the North will add to our current knowledge base and aid preservation of rare and ecologically valuable pine barrens of New England.
Capacitors are components predominantly used to stabilize voltage, store energy, and lower electrical ripples. To improve the flexibility and capacitance of capacitors, we were motivated to develop hybrid film capacitors using two emerging thin film techniques, atomic and molecular layer deposition (ALD and MLD). Validation of its operational reliability in a power module or an electrical system is critical to facilitate its adoption. Equivalent series resistance (ESR) and capacitance are key performance characteristics (PC) of a capacitor, whose degradation path and process are nonlinear and dependent. Few studies have implemented the Wiener process (WP), to capture the dependency between the PC, based on the assumption of a normally distributed performance loss, notwithstanding that the performance loss may not be normally distributed. To address this concern as well as improve the accuracy of reliability prediction, a reliability framework is proposed. The gamma distribution is found to better fit the incremental PC degradation used in this work. The derived reliability model captured the non-linearity in the PC degradation path as well as its dependency using a selected Copula function. Akaike information criterion (AIC) was used to determine the most suitable Copula. Reliability estimation based on dependency consideration shows the least mean square error (MSE) compared to reliability estimate using a model that considers only one PC or assumes independent PCs. In addition, the hybrid capacitor was compared with an aluminum oxide dielectric layer capacitor, and the result was discussed.
Quantum fluctuations (QFs) caused by zero-point phonon vibrations (ZPPVs) are known to prevent the occurrence of polar phases in bulk incipient ferroelectrics down to 0 K. On the other hand, little is known about the effects of QFs on the recently discovered topological patterns in ferroelectric nanostructures. Here, by using an atomistic effective Hamiltonian within classical Monte Carlo (CMC) and path integral quantum Monte Carlo (PI-QMC), we unveil how QFs affect the topology of several dipolar phases in ultrathin Pb(Zr0.4Ti0.6)O3 (PZT) films. In particular, our PI-QMC simulations show that the ZPPVs do not suppress polar patterns but rather stabilize the labyrinth, bimeron and bubble phases within a wider range of bias field magnitudes. Moreover, we reveal that quantum fluctuations induce a quantum critical point (QCP) separating a hexagonal bubble lattice from a liquid-like state characterized by spontaneous motion, creation and annihilation of polar bubbles at cryogenic temperatures. Finally, we show that the discovered quantum melting is associated with anomalous physical response, as, e.g., demonstrated by a negative longitudinal piezoelectric coefficient.
Modern comparative biology owes much to phylogenetic regression. At its conception, this technique sparked a revolution that armed biologists with phylogenetic comparative methods (PCMs) for disentangling evolutionary correlations from those arising from hierarchical phylogenetic relationships. Over the past few decades, the phylogenetic regression framework has become a paradigm of modern comparative biology that has been widely embraced as a remedy for shared ancestry. However, recent evidence has sown doubt over the efficacy of phylogenetic regression, and PCMs more generally, with the suggestion that many of these methods fail to provide an adequate defense against unreplicated evolution—the primary justification for using them in the first place. Importantly, some of the most compelling examples of biological innovation in nature result from abrupt lineage-specific evolutionary shifts, which current regression models are largely ill-equipped to deal with. Here we explore a solution to this problem by applying robust linear regression to comparative trait data. We formally introduce robust phylogenetic regression to the PCM toolkit with linear estimators that are less sensitive to model violations than the standard least-squares estimator, while still retaining high power to detect true trait associations. Our analyses also highlight an ingenuity of the original algorithm for phylogenetic regression based on independent contrasts, whereby robust estimators are particularly effective. Collectively, we find that robust estimators hold promise for improving tests of trait associations and offer a path forward in scenarios where classical approaches may fail. Our study joins recent arguments for increased vigilance against unreplicated evolution and a better understanding of evolutionary model performance in challenging–yet biologically important–settings.
As racial and ethnic diversity have increased in America, prejudice too has expanded. Citizens are more wary of immigrants, with attitudes toward Asian immigrants in particular worsening during COVID-19. Yet less is known about the prejudice directed at other immigrant groups during this period, with research suggesting that feeling capable of interacting with new people could reduce misgivings about diversity. A web survey was conducted in April of 2020 to test the potential for digital and physical social competence to improve attitudes toward Mexican immigrants, as the largest immigrant group in the United States ( N = 665). Interpersonal competence was inversely associated with prejudice toward Mexican immigrants, with interpersonal skills such as attentiveness, expressiveness, and mindfulness being especially valuable for prejudice reduction. Computer-mediated communication competence was indirectly associated with feeling less prejudiced, through interpersonal competence, and social presence also moderated the conversion of CMC competence into interpersonal competence, diminishing prejudice even further. Digital social capabilities encourage admiration and sympathy for immigrants by making users feel more capable of interacting with them locally. Networked settings now have the potential to train dissimilar users to interact together in person, as a way of reducing prejudice.
Two low-dose dicamba exposure trials were conducted on container-grown peach trees in Fayetteville, AR. Peach trees were ‘July Prince’ scions grafted onto ‘Guardian’ rootstock and were transplanted into 19 L containers and received experimental dicamba treatments in each year. Container trials were initiated in 2020 and repeated on new trees in 2021. In the repeated application trial, dicamba was applied at 5.6 g ae ha ⁻¹ (1/100× field rate) in five sequences: an untreated control receiving no herbicide, one treatment receiving only initial application, and three treatments receiving initial application plus sequential applications at the same rate occurring 14 d, 28 d, 14 d + 28 d after initial treatment (DAT). A separate trial assessed peach tree responses to dicamba applied at 11.2 g ae ha ⁻¹ (1/50× field rate) using a selection of nozzles with differing droplet spectrum characteristics: Turbo TeeJet® Induction (TTI11002), Air Induction Turbo TeeJet® (AITTJ60-11002), AIXR TeeJet® (AIXR11002, air induction extended range), XR TeeJet® (XR11002, extended range flat fan), and XR TeeJet® (XR1100067, extended range flat fan). Peach tree height, tree cross sectional area (TCSA) and leaf chlorophyll content were not reduced in response to any sequence of dicamba application or nozzle selection. Repeated applications of dicamba at 1/100× rate did not increase peach injury after 28 DAT. By 84 DAT, no effect of nozzle type on peach tree injury was discernable, and all treatments caused below 4% injury. No dicamba or dicamba metabolites were observed in leaf samples collected at 14, 69, or 85 DAT from trees treated with XR1100067 nor in untreated controls. While peach tree injury was observed throughout the experiment, dicamba residues were only detected consistently in 2020 from leaf samples of trees treated with dicamba at 1/50× rate using TTI1102, AITTJ60-11002, AIXR11002, and XR11002 nozzles.
This is an update of a previous review: Electronic and optical properties of strained graphene and other strained 2D materials: a review, by GG Naumis, S Barraza-Lopez, M Oliva-Leyva, H Terrones, Reports on Progress in Physics 80 (9), 096501 . Experimental and theoretical advances for straining graphene and other metallic, insulating, ferroelectric, ferroelastic, ferromagnetic and multiferroic 2D materials have been considered. Specific topics of discussion include: (i) methods to induce valley and sublattice polarisation in graphene, (ii) time-dependent strain and its impact on graphene's electronic properties, (iii) the role of local and global strain on superconductivity and other highly correlated and/or topological phases of graphene, inducing polarisation on hexagonal boron nitride monolayers via strain, (iv) measuring strain, and modifying through strain the optoelectronic properties of transition metal dichalcogenides, (v) ferroic 2D materials with intrinsic elastic ($\sigma$), electric ($\mathbf{P}$) and magnetic ($\mathbf{M}$) polarisation under strain, as well as incipient 2D multiferroics and (vi) moir'e bilayers exhibiting flat electronic bands and exotic quantum phase diagrams, and other bilayer or few-layer systems exhibiting ferroic orders tunable by rotations and shear strain. The review features the extremely recent experimental realizations of a tunable two-dimensional Quantum Spin Hall effect in germanene, of monoelemental 2D ferroelectric bismuth, and 2D multiferroic NiI_2. The document was structured for a discussion of effects taking place in monolayers first, followed by discussions concerning bilayers and few-layers, and it represents a fresh and up-to-date overview of exciting and newest developments on the fast-paced field of 2D materials.
Remote Sensing Image Captioning (RSIC) plays a crucial role in advancing semantic understanding and has increasingly become a focal point of research. Nevertheless, existing RSIC methods grapple with challenges due to the intricate multi-scale nature and multifaceted backgrounds inherent in Remote Sensing Images (RSIs). Compounding these challenges are the perceptible information disparities across diverse modalities. In response to these challenges, we propose a novel multi-scale contextual information aggregation image captioning network (MC-Net). This network incorporates an image encoder enhanced with a multi-scale feature extraction module, a feature fusion module, and a finely tuned adaptive decoder equipped with a visual-text alignment module. Notably, MC-Net possesses the capability to extract informative multiscale features, facilitated by the multilayer perceptron and transformer. We also introduce an adaptive gating mechanism during the decoding phase to ensure precise alignment between visual regions and their corresponding text descriptions. Empirical studies conducted on four publicly recognized cross-modal datasets unequivocally demonstrate the superior robustness and efficacy of MC-Net in comparison to contemporaneous RSIC methods.
This article examines the relationship between legislative civility and legislative productivity in US state legislatures. The research employs data from the National Survey of State Legislative Lobbyists and from the State Policy Innovation and Diffusion (SPID) database. The former dataset is used to generate an overall civility index for each state as developed by Kettler et al. The SPID database allows one to measure the legislative productivity of a state legislature. Employing these data, negative binomial and Poisson regression models reveal that state legislatures rated as more civil by their own lobbyists produced significantly more pieces of noteworthy legislation than those legislative bodies rated as less civil. These results suggest that the quality of internal legislative dynamics matters for legislative productivity.
As geoscience and water related enrollment and degrees continue to decline, new methods are needed to recruit and engage students in these interesting and challenging interdisciplinary fields. An existing water-themed distinguished lecture tour was reinvented and reinvigorated to include a workshop to (1) promote interdisciplinary collaboration and (2) increase student engagement in earth sciences. The Geological Society of America has dedicated foundation support for a domestic and international lecture tour to promote the scientific discipline of hydrogeology. In addition to the lecture tour with a standard presentation and meetings with faculty, staff, and students, a half-day, interactive field demonstration of the inventory and assessment techniques for springs ecosystems was conducted at a spring near the lecture site. Local faculty hosts were encouraged to engage students in the planning and implementation of the demonstration workshop. The students were provided additional training to enter the interdisciplinary ecosystem data into a cloud-sourced database and to be actively engaged in producing a publication related to the springs ecosystems inventories and assessments. Of the participants of the demonstration workshops, students at eight of the host institutions became co-authors of the resulting manuscript. With the significant investment of time, resources, and logistics to implement a lecture tour, an additional interactive, hands-on, demonstration workshop is a cost-effective way to increase student engagement and provide interdisciplinary collaboration.
It is repeatedly stressed the need to characterize the extant biodiversity in tropical ecosystems. However, inventory studies are still progressing slowly in dry ecosystems, leading to the underestimation of their true biodiversity and hindering conservation efforts. In this study, we present primary and secondary data, along with an updated list of amphibians and reptiles from two localities in the São Francisco-Gurguéia region in Piauí. Additionally, we compare the species composition between nine areas within the Caatinga, which were sampled using standardized methods over the past ten years, to examine broader spatial patterns of community composition. To survey reptiles and amphibians, we employed similar methods and sampling efforts in two areas within the Serra das Confusões National Park (SCNP) region. Our surveys recorded a total of 73 species of amphibians and reptiles, of which 24 are new distribution records for the SCNP region. Consequently, our findings increase the known herpetofauna in the region to 94 species. Despite their proximity, the two sites in the SCNP region exhibited only 42% similarity in species composition, and they differed significantly from other areas within the Caatinga. Furthermore, even the closer Caatinga areas presented differences in species composition, highlighting the necessity to evaluate biodiversity across the landscape and contribute to understanding biogeographic patterns.
Aquatic bacterial pathogens can cause severe economic loss in aquaculture industry. An opportunistic pathogen, Aeromonas hydrophila is responsible for Motile Aeromonas Septicemia, leading to high mortality rates in fish. The present study was focused on the efficacy of Aloe barbadensis replacing fishmeal diets on hematological, serum biochemical, antioxidant, histopathological parameters, and disease resistance against A. hydrophila infection in Labeo rohita. Isonitrogenous fishmeal replaced diets (FMR) were prepared with varying levels of A. barbadensis at D1 (0%) (control), D2 (25%), D3 (50%), D4 (75%) and D5 (100%) then fed to L. rohita. After 60 days of post-feeding, the experimental fish were challenged with A. hydrophila. Blood and organs were collected and examined at 1- and 15-days post infection (dpi). The results demonstrated that on 1 dpi, white blood cells (WBC), total protein, cholesterol and low-density lipoprotein (LDL) levels were significantly increased in D3 diet fed groups. The D2 and D3 diet fed group showed decreasing trends of serum glutamic pyruvic transaminase (SGPT) and antioxidant enzymes activity on 15 dpi. The histopathological architecture results clearly illustrated that the D3 diet fed group had given a higher protective effect by reducing the pathological changes associated with A. hydrophila infection in liver, intestine and muscle. Higher percentage of survival rate was also observed in D3 diet fed group. Therefore, the present study suggested that the dietary administration of A. barbadensis up to 50% fishmeal replacement (D3 diet) can elicit earlier antioxidant activity, innate immune response and improve survival rate in L. rohita against A. hydrophila infection.
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8,203 members
Ainong Shi
  • Department of Horticulture
Prabodh Kumar Bajpai
  • Department of Biological Sciences
Rohana Liyanage
  • Department of Chemistry and Biochemistry
Malcolm Cleaveland
  • Department of Geosciences
Rafael Eufrasio
  • Department of Physics
72701, Fayetteville, AR, United States
Head of institution
Dr. Joseph E. Steinmetz (Chancellor)