446 research outputs found

    Searching for Fast Optical Transients using VERITAS Cherenkov Telescopes

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    Astronomical transients are intrinsically interesting things to study. Fast optical transients (microsecond timescale) are a largely unexplored field of optical astronomy mainly due to the fact that large optical telescopes are oversubscribed. Furthermore, most optical observations use instruments with integration times on the order of seconds and are thus unable to resolve fast transients. Current-generation atmospheric Cherenkov gamma-ray telescopes, however, have huge collecting areas (e.g., VERITAS, which consists of four 12-m telescopes), larger than any existing optical telescopes, and time is typically available for such studies without interfering with gamma-ray observations. The following outlines the benefits of using a Cherenkov telescope to detect optical transients and the implementation of the VERITAS Transient Detector (TRenDy), a dedicated multi-channel photometer based on field-programmable gate arrays. Data are presented demonstrating the ability of TRenDy to detect transient events such as a star passing through its field of view and the optical light curve of a pulsar

    Using Social Media for Professional Development

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    Sean Griffin is a social media marketer with a degree in marketing from Louisiana Tech University and a background in consumer behavior, sales & entrepreneurship and communications (business and interdepartmental). Topics to be covered at this seminar include: - Social media etiquette - LinkedIn for beginners and intermediate users - Personal branding and marketing - How to use social media to find prospective employers, connections, and research Come at 3:30pm for refreshments, speaker at 4:00p

    Development of a Silicon Tracker for the All-Sky Medium Energy Gamma-ray Observatory Prototype

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    The gamma-ray sky from several hundred keV to a hundred MeV has remained largely unexplored due to the challenging nature of detecting gamma rays in this regime. At lower energies, Compton scattering is the dominant interaction process whereas at higher energies pair production dominates, with a crossover at a few MeV. Thus, an instrument designed to work in this energy range must be optimized for both Compton and pair-production events. AMEGO, the All-sky Medium Energy Gamma-ray Observatory, a Probe-class mission in consideration for the 2020 decadal survey, is designed to operate at energies from 200 keV to > 10 GeV with over an order of magnitude increase in sensitivity and with superior angular and energy resolution compared to previous instruments. AMEGO comprises four major subsystems: a plastic anticoincidence detector for rejecting cosmic-ray events, a silicon tracker for tracking pair-production products and tracking and measuring the energies of Compton-scattered electrons, a cadmium-zinc-telluride (CZT) calorimeter for measuring the energy and location of Compton scattered photons, and a CsI calorimeter for measuring the energy of the pair-production products at high energies. A prototype instrument, known as ComPair, is under development at NASAs Goddard Space Flight Center and the US Naval Research Laboratory. In this contribution, we provide details on the development of the silicon tracker subsystem

    A Reformers\u27 Union: Land Reform, Labor, and the Evolution of Antislavery Politics, 1790–1860

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    “A Reformers’ Union: Land Reform, Labor, and the Evolution of Antislavery Politics, 1790–1860” offers a critical revision of the existing literature on both the early labor and antislavery movements by examining the ideologies and organizational approaches that labor reformers and abolitionists used to challenge both the expansion of slavery and the spread of market relationships. Extending the timeframe of the antislavery and labor movements backwards to the 1790s, this dissertation situates the origins of the pre-Civil War labor movement in republican ideology and currents of transatlantic radical thought, and traces the rise of agrarian and communitarian labor reform against the backdrop of the growing economic and political salience of chattel slavery. While acknowledging and seeking to explain the real differences that divided labor reformers and abolitionists throughout the period, A Reformers\u27 Union argues that important strains within each movement shared common understandings about the limitations of private property and the reach of the market. These shared understandings, and the discursive debates that shaped them, eventually fostered important organizational and institutional connections between the two movements, even as developments surrounding the slavery’s expansion in the 1840s and 50s inextricably linked the cause of land reform to antislavery. Land and labor reformers made critical contributions to the ideological foundations and popular appeal of the Liberty, Free Soil, and Republican parties, thus highlighting both the limitations and the potential of the politics of “free soil” and “free labor.

    Δ\Delta-Springer varieties and Hall-Littlewood polynomials

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    The Δ\Delta-Springer varieties are a generalization of Springer fibers introduced by Levinson, Woo, and the author that have connections to the Delta Conjecture from algebraic combinatorics. We prove a positive Hall-Littlewood expansion formula for the graded Frobenius characteristic of the cohomology ring of a Δ\Delta-Springer variety. We do this by interpreting the Frobenius characteristic in terms of counting points over a finite field Fq\mathbb{F}_q and partitioning the Δ\Delta-Springer variety into copies of Springer fibers crossed with affine spaces. As a special case, our proof method gives a geometric meaning to a formula of Haglund, Rhoades, and Shimozono for the Hall-Littlewood expansion of the symmetric function in the Delta Conjecture at t=0t=0.Comment: 21 page
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