6,471 research outputs found

    Impact of basidiomycete fungi on the wettability of soil contaminated with a hydrophobic polycyclic aromatic hydrocarbon

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    Polyaromatic hydrocarbons (PAHs) present a challenge to bioremediation because they are hydrophobic, thus influencing the water availability and repellency of soil. The addition of different concentrations of the PAH, anthracene, showed it to induce moderate levels of repellency. We investigated the efficacy of three basidiomycete fungal species on improving the wettability of soil by reducing repellency caused by contamination of soil with 7 ppm anthracene. A microcosm system was used that enabled determination of the impact of fungi on wettability at three locations down a 30 mm deep repacked soil core. Before incubation with fungi, the contaminated soil had a repellency of R = 3.12 ± 0.08 (s.e.). After 28 days incubation, Coriolus versicolor caused a significant reduction in repellency to R = 1.79 ± 0.35 (P <0.001) for the top section of the soil in a microcosm. Phanerochaete chrysosporium and Phlebia radiata did not influence repellency. None of the fungi had an effect at 20 mm depth

    Review of Approaching Emily Dickinson: Critical Currents and Crosscurrents Since1960

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    Mutagens in contaminated soil: a review

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    The intentional and accidental discharges of toxic pollutants into the lithosphere results in soil contamination. In some cases (e.g., wood preserving wastes, coal-tar, airborne combustion by-products), the contaminated soil constitutes a genotoxic hazard. This work is a comprehensive review of published information on soil mutagenicity. In total, 1312 assessments of genotoxic activity from 118 works were examined. The majority of the assessments (37.6%) employed the Salmonella mutagenicity test with strains TA98 and/or TA100. An additional 37.6% of the assessments employed a variety of plant species (e.g., Tradescantia clone 4430, Vicia faba, Zea mays, Allium cepa) to assess mutagenic activity. The compiled data on Salmonella mutagenicity indicates significant differences (p \u3c 0.0001) in mean potency (revertents per gram dry weight) between industrial, urban, and rural/agricultural sites. Additional analyses showed significant empirical relationships between S9-activated TA98 mutagenicity and soil polycyclic aromatic hydrocarbon (PAH) concentration (r2 = 0.19 to 0.25, p \u3c 0.0001), and between direct-acting TA98 mutagenicity and soil dinitropyrene (DNP) concentration (r2 = 0.87, p \u3c 0.0001). The plant assay data revealed excellent response ranges and significant differences between heavily contaminated, industrial, rural/agricultural, and reference sites, for the anaphase aberration in Allium cepa (direct soil contact) and the waxy locus mutation assay in Zea mays (direct soil contact). The Tradescantia assays appeared to be less responsive, particularly for exposures to aqueous soil leachates. Additional data analyses showed empirical relationships between anaphase aberrations in Allium, or mutations in Arabidopsis, and the 137Cs contamination of soils. Induction of micronuclei in Tradescantia is significantly related to the soil concentration of several metals (e.g., Sb, Cu, Cr, As, Pb, Cd, Ni, Zn). Review of published remediation exercises showed effective removal of genotoxic petrochemical wastes within one year. Remediation of more refractory genotoxic material (e.g., explosives, creosote) frequently showed increases in mutagenic hazard that remained for extended periods. Despite substantial contamination and mutagenic hazards, the risk of adverse effect (e.g., mutation, cancer) in humans or terrestrial biota is difficult to quantify

    Academic Tax Articles 1980-2000: Tax Faculty Productivity Analyses

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    This study extends knowledge pertaining to accounting research productivity in taxation and provides data that may be useful for faculty career development or assessment purposes by administrators.  The authors develop an academic tax article database that contains research from 1980 through 2000 and use it to review tax faculty publication quantity and timing over a 20-year career window for both those at doctoral and non-doctoral granting institutions.  Results indicate that publication rates tend to spike within the first five years in academia for faculty at both doctoral and non-doctoral institutions and trail off from that point to year +20.  Further, faculty at doctoral schools published almost twice as many academic tax articles as faculty at non-doctoral institutions.  Relative publication differences between faculty at the two school types remain constant over time.  Additional insights include that non-tax accounting faculty contributed to almost half of all academic tax articles in the study, most faculty retain the tax designation during the first 20 years of their career, movement to doctoral schools by tax faculty happens early in a career, and in contrast, movement from doctoral schools happens later in academia

    Healthcare Price Transparency: Policy Approaches and Estimated Impacts on Spending

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    Healthcare price transparency discussions typically focus on increasing patients' access to information about their out-of-pocket costs, but that focus is too narrow and should include other audiences -- physicians, employers, health plans and policymakers -- each with distinct needs and uses for healthcare price information. Greater price transparency can reduce U.S. healthcare spending.For example, an estimated 100billioncouldbesavedoverthenext10yearsifthreeselectinterventionswereundertaken.However,mostoftheprojectedsavingscomefrommakingpriceinformationavailabletoemployersandphysicians,accordingtoananalysisbyresearchersattheformerCenterforStudyingHealthSystemChange(HSC).Basedonthecurrentavailabilityandmodestimpactofplanbasedtransparencytools,requiringallprivateplanstoprovidepersonalizedoutofpocketpricedatatoenrolleeswouldreducetotalhealthspendingbyanestimated100 billion could be saved over the next 10 years if three select interventions were undertaken. However, most of the projected savings come from making price information available to employers and physicians, according to an analysis by researchers at the former Center for Studying Health System Change (HSC). Based on the current availability and modest impact of plan-based transparency tools, requiring all private plans to provide personalized out-of-pocket price data to enrollees would reduce total health spending by an estimated 18 billion over the next decade. While 18billionisasubstantialdollaramount,itislessthanatenthofapercentofthe18 billion is a substantial dollar amount, it is less than a tenth of a percent of the 40 trillionin total projected health spending over the same period. In contrast, using state all-payer claims databases to gather and report hospital-specific prices might reduce spending by an estimated $61 billion over 10 years.The effects of price transparency depend critically on the intended audience, the decision-making context and how prices are presented. And the impact of price transparency can be greatly amplified if target audiences are able and motivated to act on the information. Simply providing prices is insufficient to control spending without other shifts in healthcare financing, including changes in benefit design to make patients more sensitive to price differences among providers and alternative treatments. Other reforms that can amplify the impact of price transparency include shifting from fee-for-service payments that reward providers for volume to payment methods that put providers at risk for spending for episodes of care or defined patient populations. While price transparency alone seems unlikely to transform the healthcare system, it can play a needed role in enabling effective reforms in value-based benefit design and provider payment

    Constraints on the correlation between QSO luminosity and host halo mass from high-redshift quasar clustering

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    Recent measurements of high-redshift QSO clustering from the Sloan Digital Sky Survey indicate that QSOs at z~4 have a bias b~14. We find that this extremely high clustering amplitude, combined with the corresponding space density, constrains the dispersion in the L-Mhalo relation to be less than 50% at 99% confidence for the most conservative case of a 100% duty cycle. This upper limit to the intrinsic dispersion provides as strong a constraint as current upper limits to the intrinsic dispersion in the local M_BH-sigma relation and the ratio of bolometric to Eddington luminosity of luminous QSOs.Comment: 6 pages, 4 figures. Minor revisions to address questions from referee. References update

    An Examination of Educational Success

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    The Gravitational Lens Candidate FBQ 1633+3134

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    We present our ground-based optical imaging, spectral analysis, and high resolution radio mapping of the gravitational lens candidate FBQ 1633+3134. This z=1.52, B=17.7 quasar appears double on CCD images with an image separation of 0.66 arcseconds and a flux ratio of ~3:1 across BVRI filters. A single 0.27 mJy radio source is detected at 8.46 GHz, coincident to within an arcsecond of both optical components, but no companion at radio wavelengths is detected down to a flux level of 0.1 mJy (3 sigma). Spectral observations reveal a rich metal-line absorption system consisting of a strong Mg II doublet and associated Fe I and Fe II absorption features, all at an intervening redshift of z=0.684, suggestive of a lensing galaxy. Point spread function subtraction however shows no obvious signs of a third object between the two quasar images, and places a detection limit of I > 23.0 if such an object exists. Although the possibility that FBQ 1633+3134 is a binary quasar cannot be ruled out, the evidence is consistent with it being a single quasar lensed by a faint, metal-rich galaxy.Comment: 24 pages, 5 figures. Accepted by AJ. A calibration error affecting B and V band apparent magnitudes has been corrected. The conclusions of the paper are not change

    A Comparison of Modified Team-Based Learning and Lecture-Based Instruction in Occupational Therapy Education

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    This study explored the comparative effectiveness of team-based learning and lecture-based instruction in consecutive cohorts of occupational therapy students. Further, the study explored student perceptions of team-based learning. The mixed method study employed a two-group, quasi-experimental design and a broad qualitative design using thematic analysis with a convenience sample of consecutive occupational therapy student cohorts (N=70, N=62) in a human movement class. Cohort A (N=70) received instruction using a lecture-based instruction (LBI) approach and individual assessment. Cohort B (N=62) received modified team-based learning (TBL). Mid-term, final examination, and final course grades were compared. Thematic analysis was employed to assess student perceptions of TBL as an instructional method. Students receiving LBI had higher mid-term scores than those receiving TBL (p=.000). Final examination scores were also higher for LBI when compared to TBL (p=.000). However, the final course grade score showed no significant difference between LBI and TBL (p=.562). Thematic analysis revealed that students felt positive about the TBL instructional method. Further, students who participated in the TBL class perceived less academic stress, and believed testing and competency assessments were effective reflections of their learning. Both TBL and LBI are viable methods for occupational therapy educators to use in human movement/kinesiology-based courses
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