200 research outputs found

    Rural Superintendents as Political Agents: Grassroots Advocacy in Appalachian Districts of Southeast Ohio

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    This qualitative inquiry explores the narratives of rural superintendents regarding their roles as moral agents in the politics of public school settings and how they view their moral and political advocacy as grassroots activism for student and community rights. Insights from superintendent narratives provided themes about the history, practice, and expectations of school leaders as political agents within their respective communities. These themes focused on activism and advocacy for equitable funding and policymaking that specifically related to transportation, testing, and technology. Findings describe and define how superintendents make meaning of their political and public obligations and provide data that can help leadership preparation programs better prepare candidates for meaningful political practice

    Molecular transport junctions: Current from electronic excitations in the leads

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    Using a model comprising a 2-level bridge connecting free electron reservoirs we show that coupling of a molecular bridge to electron-hole excitations in the leads can markedly effect the source-drain current through a molecular junction.In some cases, e.g. molecules that exhibit strong charge transfer transitions, the contribution from electron-hole excitations can exceed the Landauer elastic current and dominate the observed conduction.Comment: 4 pages, 2 figures, submitted to PR

    Acylation of the Lipooligosaccharide of Haemophilus influenzae and Colonization: an htrB Mutation Diminishes the Colonization of Human Airway Epithelial Cells

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    Haemophilus influenzae is a commensal and opportunistic pathogen of the human airways. A number of surface molecules contribute to colonization of the airways by H. influenzae, such as adhesins, including structures found in the lipooligosaccharide (LOS). A human bronchiolar xenograft model was employed to investigate the host-bacterial interactions involved in the colonization of the airway by H. influenzae. Differential display was used to identify H. influenzae mRNA that reflect genes which were preferentially expressed in the xenograft compared to growth. Eleven mRNA fragments had consistent increased expression when the bacteria grew in xenografts. On sequencing these fragments, eight open reading frames were identified. Three of these had no match in the NCBI or the TIGR database, while an additional three were homologous to genes involved in heme or iron acquisition and utilization: two of the mRNAs encoded proteins homologous to enzymes involved in LOS biosynthesis: a heptosyl transferase (rfaF) involved in the synthesis of the LOS core and a ketodeoxyoctonate phosphate-dependent acyltransferase (htrB) that performs one of the late acylation reactions in lipid A synthesis. Inoculation of human bronchiolar xenografts revealed a significant reduction in colonization capacity by htrB mutants. In vitro, htrB mutants elicited lesser degrees of cytoskeletal rearrangement and less stimulation of host cell signaling with 16HBE14o- cells and decreased intracellular survival. These results implicate acylation of H. influenzae lipid A as playing a key role in the organisms' colonization of the normal airway

    MnNiO3 revisited with modern theoretical and experimental methods

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    MnNiO3 is a strongly correlated transition metal oxide that has recently been investigated theoretically for its potential application as an oxygen-evolution photocatalyst. However, there is no experimental report on critical quantities such as the band gap or bulk modulus. Recent theoretical predictions with standard functionals such as LDA+U and HSE show large discrepancies in the band gaps (about 1.23 eV), depending on the nature of the functional used. Hence there is clearly a need for an accurate quantitative prediction of the band gap to gauge its utility as a photocatalyst. In this work, we present a diffusion quantum Monte Carlo study of the bulk properties of MnNiO3 and revisit the synthesis and experimental properties of the compound. We predict quasiparticle band gaps of 2.0(5) eV and 3.8(6) eV for the majority and minority spin channels, respectively, and an equilibrium volume of 92.8 Ã…3, which compares well to the experimental value of 94.4 Ã…3. A bulk modulus of 217 GPa is predicted for MnNiO3. We rationalize the difficulty for the formation of ordered ilmenite-type structure with specific sites for Ni and Mn to be potentially due to the formation of antisite defects that form during synthesis, which ultimately affects the physical properties of MnNiO3

    The End or Beginning? Either Way, the Credits Are Not Rolling Yet!

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    (First paragraph) Thank you to all our reviewers, editorial board members, authors, and those who chose the Journal of Urban Mathematics Education (JUME) as their outlet of choice this past year. JUME has had many recent successes, and we in the editorial team plan to release the salient performance data for the journal. For JUME to advance its mission, we believe that accountability and transparency are essential. To this end, our readers will from now on receive an annual progress report about JUME in our first issue of each year

    A Comparison of Embedded and Nonembedded Print Coverage of the U.S. Invasion and Occupation of Iraq

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    This study examines the impact of embedded versus nonembedded (unilateral) news coverage during the U.S. invasion and occupation of Iraq. A content analysis was conduycted of the Washington Post, New York Times, Los Angeles Times, and Chicago Tribune news coverage of the invasion and occupation examining whether embedded and nonembedded new reports were different and, if so, how. News reports were examined for differences in tone toward the military, trust in the military, framing, and authoritativeness. The results of the study revealed significant differences in overall tone toward the military, trust in military personnel, framing, and authoritativeness between embedded and nonembedded articles.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Behavior of a Metabolic Cycling Population at the Single Cell Level as Visualized by Fluorescent Gene Expression Reporters

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    BACKGROUND: During continuous growth in specific chemostat cultures, budding yeast undergo robust oscillations in oxygen consumption that are accompanied by highly periodic changes in transcript abundance of a majority of genes, in a phenomenon called the Yeast Metabolic Cycle (YMC). This study uses fluorescent reporters of genes specific to different YMC phases in order to visualize this phenomenon and understand the temporal regulation of gene expression at the level of individual cells within the cycling population. METHODOLOGY: Fluorescent gene expression reporters for different phases of the YMC were constructed and stably integrated into the yeast genome. Subsequently, these reporter-expressing yeast were used to visualize YMC dynamics at the individual cell level in cultures grown in a chemostat or in a microfluidics platform under varying glucose concentrations, using fluorescence microscopy and quantitative Western blots. CONCLUSIONS: The behavior of single cells within a metabolic cycling population was visualized using phase-specific fluorescent reporters. The reporters largely recapitulated genome-specified mRNA expression profiles. A significant fraction of the cell population appeared to exhibit basal expression of the reporters, supporting the hypothesis that there are at least two distinct subpopulations of cells within the cycling population. Although approximately half of the cycling population initiated cell division in each permissive window of the YMC, metabolic synchrony of the population was maintained. Using a microfluidics platform we observed that low glucose concentrations appear to be necessary for metabolic cycling. Lastly, we propose that there is a temporal window in the oxidative growth phase of the YMC where the cycling population segregates into at least two subpopulations, one which will enter the cell cycle and one which does not

    What Does the Geometry of the HβBLR Depend On?

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    We combine our dynamical modeling black-hole mass measurements from the Lick AGN Monitoring Project 2016 sample with measured cross-correlation time lags and line widths to recover individual scale factors, f, used in traditional reverberation-mapping analyses. We extend our sample by including prior results from Code for AGN Reverberation and Modeling of Emission Lines (CARAMEL) studies that have utilized our methods. Aiming to improve the precision of black-hole mass estimates, as well as uncover any regularities in the behavior of the broad-line region (BLR), we search for correlations between f and other AGN/BLR parameters. We find (i) evidence for a correlation between the virial coefficient log10(fmean,σ) and black-hole mass, (ii) marginal evidence for a similar correlation between log10( frms,σ) and black-hole mass, (iii) marginal evidence for an anticorrelation of BLR disk thickness with log10( fmean,FWHM) and log10( frms,FWHM), and (iv) marginal evidence for an anticorrelation of inclination angle with log10( fmean,FWHM), log10( frms,σ), and log10( fmean,σ). Last, we find marginal evidence for a correlation between line-profile shape, when using the root-mean-square spectrum, log10(FWHM/σ)rms, and the virial coefficient, log10( frms,σ), and investigate how BLR properties might be related to line-profile shape using CARAMEL models
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