538 research outputs found

    Ichthyofaunal Diversification and Distribution in the Big Creek Watershed, Craighead and Greene Counties, Arkansas

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    Big Creek is a relatively small deltaic stream, in northeastern Arkansas, in an area of intense cultivation. Recently it has been dredged in the interest of flood control. Lost Creek and Mud Creek are the major tributaries of Big Creek and collectively drain the Big Creek watershed. The streams were found to have relatively low alkalinity, moderate carbon dioxide, adequate oxygen values, and relatively high turbidity. Channeling of Big Creek and Lost Creek has effectively destroyed distinct pool-riffle biocies and reduced the number of acceptable spawning areas. Lost Creek, also, receives effluent from residential dwellings, a secondary treatment sewage plant, and a meat rendering plant. Mud Creek, in the absence of channeling and deleterious effects of effluents, provided a relatively greater diversity of habitat than did Big Creek or Lost Creek

    On the interpretation of ionospheric resonances stimulated by Alouette I

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    Interpretation of ionospheric resonances stimulated by Alouette I - electrostatic plasma wave theory, observation of group delay, and application to ionospher

    Face Coverings Differentially Alter Valence Judgments of Emotional Expressions

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    Face masks that prevent disease transmission obscure facial expressions, impairing nonverbal communication. We assessed the impact of lower (masks) and upper (sunglasses) face coverings on emotional valence judgments of clearly valenced (fearful, happy) and ambiguously valenced (surprised) expressions, the latter of which have both positive and negative meanings. Masks, but not sunglasses, impaired judgments of clearly valenced expressions compared to faces without coverings. Drift diffusion models revealed that lower, but not upper, face coverings slowed evidence accumulation and affected differences in non-judgment processes (i.e., stimulus encoding, response execution time) for all expressions. Our results confirm mask-interference effects in nonverbal communication. The findings have implications for nonverbal and intergroup communication, and we propose guidance for implementing strategies to overcome mask-related interference

    Averaging facial expression over time

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    The visual system groups similar features, objects, and motion (e.g., Gestalt grouping). Recent work suggests that the computation underlying perceptual grouping may be one of summary statistical representation. Summary representation occurs for low-level features, such as size, motion, and position, and even for high level stimuli, including faces; for example, observers accurately perceive the average expression in a group of faces (J

    Equality of Participation Online Versus Face to Face: Condensed Analysis of the Community Forum Deliberative Methods Demonstration

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    Online deliberation may provide a more cost-effective and/or less inhibiting environment for public participation than face to face (F2F). But do online methods bias participation toward certain individuals or groups? We compare F2F versus online participation in an experiment affording within-participants and cross-modal comparisons. For English speakers required to have Internet access as a condition of participation, we find no negative effects of online modes on equality of participation (EoP) related to gender, age, or educational level. Asynchronous online discussion appears to improve EoP for gender relative to F2F. Data suggest a dampening effect of online environments on black participants, as well as amplification for whites. Synchronous online voice communication EoP is on par with F2F across individuals. But individual-level EoP is much lower in the online forum, and greater online forum participation predicts greater F2F participation for individuals. Measured rates of participation are compared to self-reported experiences, and other findings are discussed.Comment: 14 pages, 10 tables, to appear in Efthimios Tambouris, Panos Panagiotopoulos, {\O}ystein S{\ae}b{\o}, Konstantinos Tarabanis, Michela Milano, Theresa Pardo, and Maria Wimmer (Editors), Electronic Participation: Proceedings of the 7th IFIP WG 8.5 International Conference, ePart 2015 (Thessaloniki, August 30-September 2), Springer LNCS Vol. 9249, 201

    New insights into the drainage of inundated ice-wedge polygons using fundamental hydrologic principles

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    The pathways and timing of drainage from the inundated centers of ice-wedge polygons in a warming climate have important implications for carbon flushing, advective heat transport, and transitions from methane to carbon dioxide dominated emissions. Here, we expand on previous research using a recently developed analytical model of drainage from a low-centered polygon. Specifically, we perform (1) a calibration to field data identifying necessary model refinements and (2) a rigorous model sensitivity analysis that expands on previously published indications of polygon drainage characteristics. This research provides intuition on inundated polygon drainage by presenting the first in-depth analysis of drainage within a polygon based on hydrogeological first principles. We verify a recently developed analytical solution of polygon drainage through a calibration to a season of field measurements. Due to the parsimony of the model, providing the potential that it could fail, we identify the minimum necessary refinements that allow the model to match water levels measured in a low-centered polygon. We find that (1) the measured precipitation must be increased by a factor of around 2.2, and (2) the vertical soil hydraulic conductivity must decrease with increasing thaw depth. Model refinement (1) accounts for runoff from rims into the ice-wedge polygon pond during precipitation events and possible rain gauge undercatch, while refinement (2) accounts for the decreasing permeability of deeper soil layers. The calibration to field measurements supports the validity of the model, indicating that it is able to represent ice-wedge polygon drainage dynamics. We then use the analytical solution in non-dimensional form to provide a baseline for the effects of polygon aspect ratios (radius to thaw depth) and coefficient of hydraulic conductivity anisotropy (horizontal to vertical hydraulic conductivity) on drainage pathways and temporal depletion of ponded water from inundated ice-wedge polygon centers. By varying the polygon aspect ratio, we evaluate the relative effect of polygon size (width), inter-annual increases in active-layer thickness, and seasonal increases in thaw depth on drainage. The results of our sensitivity analysis rigorously confirm a previous analysis indicating that most drainage through the active layer occurs along an annular region of the polygon center near the rims. This has important implications for transport of nutrients (such as dissolved organic carbon) and advection of heat towards ice-wedge tops. We also provide a comprehensive investigation of the effect of polygon aspect ratio and anisotropy on drainage timing and patterns, expanding on previously published research. Our results indicate that polygons with large aspect ratios and high anisotropy will have the most distributed drainage, while polygons with large aspect ratios and low anisotropy will have their drainage most focused near their periphery and will drain most slowly. Polygons with small aspect ratios and high anisotropy will drain most quickly. These results, based on parametric investigation of idealized scenarios, provide a baseline for further research considering the geometric and hydraulic complexities of ice-wedge polygons

    Reported Barriers to Hepatitis C Treatment among Pregnant and Early-Parenting Mothers Undergoing Substance Use Disorder Treatment in One U.S. State

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    Nationwide, the prevalence of the hepatitis C virus (HCV) has risen in recent years. At least 90% of infected persons must be treated to achieve global elimination targets. The current study aimed to explore barriers to, and facilitators of, direct-acting antiviral (DAA) HCV treatment uptake amongst pregnant and early-parenting women undergoing comprehensive substance use treatment. Twenty participants with documented HCV antibody positivity were recruited from two substance use treatment centers in central Kentucky. Semi-structured interviews were conducted to explore knowledge about HCV, previous experiences, and intentions to seek care. Themes were extracted using an inductive analytical approach. Most participants were aware of the dangers posed by HCV infection. However, there was a high degree of misinformation about transmission mechanisms and treatment eligibility requirements. Low priority for HCV treatment also surfaced as a barrier to treatment uptake. Participants reported being unable to seek care due to time and resource limitations in the presence of a highly demanding treatment process. Findings from the current study suggest that more work is needed to eliminate residual barriers that limit access to HCV treatment among pregnant and early-parenting women in treatment for substance use disorder

    Cross-Sections of Large-Angle Hadron Production in Proton- and Pion-Nucleus Interactions III: Tantalum Nuclei and Beam Momenta from +/-3 Gev/c to +/-15 Gev/c

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    We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% nuclear interaction length thick stationary tantalum target, of proton and pion beams with momentum from +/-3 GeV/c to +/-15 GeV/c. Results are given for secondary particles with production angles between 20 and 125 degrees. They are of particular relevance for the optimization of the design parameters of the proton driver of a neutrino factory.Comment: 68 pages, 12 figures, corrections in v2: added 'HARP -CDP group' to author name, corrected two typos in Table 4 (last two p values for 65-90 degrees were all 0.972

    Framing ideology: How Time magazine represents nationalism and identities through visual reporting

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    Visual images in news photographs guide individuals’ understandings of people, places and events, especially when news audiences are unable to personally experience those represented images. When 41 Time newsmagazine covers from the first five years of the U.S.-led war on Iraq are considered through a framing analysis, four frames surface: The Sanitized War, Against the Powers-That-Be; The American Soldier in a Time of War; and The "Other" of the War, or "Us versus Them." These findings highlight the power of media messages to frame identity ideologies and stress the importance of complementing quantitative studies with qualitative approaches. ----------------------------------------------------- Las imágenes periodísticas orientan la comprensión sobre individuos, lugares y eventos, especialmente cuando las audiencias no pueden experimentar personalmente aquello representado en la prensa. Al analizar 41 portadas de la revista Time de los primeros cinco años de la Guerra de Irak liderada por los Estados Unidos, se identifican cuatro encuadres: La guerra desinfectada, Contra el poder, El soldado estadounidense en tiempos de guerra y El otro en la guerra (Ellos contra nosotros). Estos hallazgos subrayan el poder de los mensajes mediales para enmarcar ideologías de identidad y destacan la importancia de complementar estudios cuantitativos con enfoques cualitativos
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