14,979 research outputs found

    Exciton-polariton emission from organic semiconductor optical waveguides

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    We photo-excite slab polymer waveguides doped with J-aggregating dye molecules and measure the leaky emission from strongly coupled waveguide exciton polariton modes at room temperature. We show that the momentum of the waveguide exciton polaritons can be controlled by modifying the thickness of the excitonic waveguide. Non-resonantly pumped excitons in the slab excitonic waveguide decay into transverse electric and transverse magnetic strongly coupled exciton waveguide modes with radial symmetry. These leak to cones of light with radial and azimuthal polarizations

    Tests of Ocean-Tide Models by Analysis of Satellite-To-Satellite Range Measurements: An Update

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    Seven years of GRACE intersatellite range-rate measurements are used to test the new ocean tide model FES2014 and to compare against similar results obtained with earlier models. These qualitative assessments show that FES2014 represents a marked improvement in accuracy over its earlier incarnation, FES2012, with especially notable improvements in the Arctic Ocean for constituents K(sub 1) and S(sub 2). Degradation appears to have occurred in two anomalous regions: the Ross Sea for the O(sub 1) constituent and the Weddell Sea for M(sub 2)

    Effects of virus infection on release of volatile organic compounds from insect-damaged bean, Phaseolus vulgaris

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    Insects can serve as important vectors of plant pathogens, especially viruses. Insect feeding on plants causes the systemic release of a wide range of plant volatile compounds that can serve as an indirect plant defense by attracting natural enemies of the herbivorous insect. Previous work suggests that the Mexican bean beetle (Epilachna varivestis) prefers to feed on plants infected by either of two viruses that it is known to transmit: Southern bean mosaic virus (SBMV) or Bean pod mottle virus (BPMV). A possible explanation for the preferred feeding on virus-infected tissues is that the beetles are attracted by volatile signals released from leaves. The purpose of this work was to determine whether volatile compounds from virus-infected plants are released differentially from those emitted by uninfected plants. To test the hypothesis, common bean plants (Phaseolus vulgaris cv. Black Valentine) were inoculated with either BPMV, SBMV, or a mixture of both viruses, and infected plants were compared to uninfected plants. An Ouchterlony assay was used with SBMVand BPMV-specific antisera to confirm the presence of virus in inoculated plants. RNA blot analysis was performed on tissue from each plant and indicated that a well-characterized defense gene, encoding phenylalanine ammonia-lyase (PAL), was not induced in systemic tissue following virus infection. Plant volatiles were collected—and analyzed via gas chromatography (GC)—from plants that were either undamaged or beetle-damaged. In undamaged plants, there were no measurable differences in profiles or quantities of compounds released by uninfected and virus-infected plants. After Mexican bean beetles were allowed to feed on plants for 48 h, injured plants released several compounds that were not released from undamaged plants. Lower quantities of volatile compounds were released from virus-infected plants suggesting that enhanced release of plant-derived volatile organic compounds is not the cause for attraction of Mexican bean beetles to virus-infected plants

    Promoting Librarian-Faculty Collaboration to Advance Information Literacy: Hanover College's Pilot Program

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    In 2005, a team from Hanover College (Academic Dean, Library Director, Faculty member) took part in Transformation of the College Library, a workshop offered by The Council of Independent Colleges. The focus of the meeting, advancing Information Literacy, culminated in participating instructions outlining an actionable plan for implementing/improving these important standards on their campus. As a result, the Duggan Library at Hanover College formed a year-long pilot program designed to support faculty wishing to incorporate information literacy concepts into their courses. During the Winter term of 2006, the Library completed a series of classes with topics ranging from research assignment development, to plagiarism and web technology. The remainder of the pilot program includes a session on evaluation followed by a campus-wide forum in January 2007 as Hanover considers the next steps in the Information Literacy initiative

    Numic fires: modeling the effects of anthropogenic fire on foraging decisions in the Great Basin

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    PosterAcross Western North America, hunter-gatherers modified their surrounding environment with the application of fire (1; 11; 15). However, to date we lack a general theoretical framework to investigate the reasons why people would burn or its effects on traditional foraging economies. To begin to fill in these gaps, here we examine the immediate benefits fire may provide in the context of driving rabbits in shrubland ecosystems across the ethnographic Great Basin occupied by Numic speaking foragers. Poster for the Society for American Archaeology 80th Annual Meeting, San Francisco, CA (2015)

    An Environmental Study of the Origin, Distribution, and Bioaccumulation of Selenium in Kentucky and Barkley Lakes

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    Many samples of water, bottom sediment, and fish were analyzed for toxic metal ion content. The samples were collected from several selected sites along Kentucky and Barkley Lakes as well as the Cumberland River and several sub-impoundments along these aquatic systems. Emphasis was placed on selenium, although several other metal ions were determined. The results showed that there are no serious pollution problems with As, Cd, Cr, Cu, Hg, Pb, Se, Sr, Zn, or Zr at any of the sites examined. Actually, none of the trace metals examined even come close to the EPA limits on fish, with the exception of lead in the White Crappie and mercury in the Bass. There appears to be no serious problem with lead in White Crappie as only two fish out of a total of nineteen were above the limit of 2 PPM. The same holds for mercury in the bass as only three fish out of thirty four were above the 0.5 PPM level. Water and sediment analyses for the above mentioned metal ions fell well within expected normal limits for unpolluted fresh water systems. No point sources could be identified for any of the metal ions. This is in contrast with results obtained on the lower Tennessee River by Hancock, et al. in which a large chemical complex was found to contribute significant quantities of trace metals. No significant seasonal variation of trace element content was observed in any of the sample types. Since the selenium content of all samples was so low, no laboratory bioaccumulation data were obtained. No general correlation between fish length and trace element content could be established, although there was a relationship for some elements, usually positive but sometimes negative. There was some correlation between trace element content and area and between elemental content and species of fish. However, these relationships are complex and depend on the trace element studied. The most important conclusion to be drawn from this study is that at this time there appears to be little problem with trace metal pollution in Kentucky and Barkley Lakes

    Diversity Matters: Race, Gender and Ethnicity in Legal Education.

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    This Article presents more evidence of the inequality that persists in legal education for students. Based on a survey of University of Florida law students conducted in 2001, this study reaffirms the existence of differential experience and an inegalitarian culture in legal education. However, it also demonstrates the importance of diversity and the recognition by a significant majority of students of the value of race and gender pluralism. These competing findings provide a clear guide to the future direction of legal education
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