536 research outputs found

    Comparison of non-archimedean and logarithmic mirror constructions via the Frobenius structure theorem

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    For a log Calabi Yau pair (X,D) with X\D affine, satisfying either assumption 1.1 of "The canonical wall structure and intrinsic mirror symmetry" or contains a Zariski dense torus, we prove under the condition that D is the support of a nef divisor, that structure constants defining a trace form on the mirror algebra constructed by Gross-Siebert are given by the naive curve count defined by Keel-Yu in definition 1.1 of "The Frobenius structure theorem for log Calabi-Yau varieties containing a torus". As a corollary, we deduce the equality of the mirror algebras constructed by Gross-Siebert and Keel-Yu in the case X\D contains a Zariski dense torus. In addition, we use this result to prove a mirror conjecture proposed by Mandel in "Fano mirror periods from the Frobenius structure conjecture" for Fano pairs satisfying assumption 1.1.Comment: 41 page

    Letter to Philander Chase

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    Johnston offers condolences for the death of Philander Chase Jr. and tells Bp. Chase that his friends in Cincinnati are eager to see him.https://digital.kenyon.edu/chase_letters/1260/thumbnail.jp

    A tractable genotype-phenotype map for the self-assembly of protein quaternary structure

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    The mapping between biological genotypes and phenotypes is central to the study of biological evolution. Here we introduce a rich, intuitive, and biologically realistic genotype-phenotype (GP) map, that serves as a model of self-assembling biological structures, such as protein complexes, and remains computationally and analytically tractable. Our GP map arises naturally from the self-assembly of polyomino structures on a 2D lattice and exhibits a number of properties: redundancy\textit{redundancy} (genotypes vastly outnumber phenotypes), phenotype bias\textit{phenotype bias} (genotypic redundancy varies greatly between phenotypes), genotype component disconnectivity\textit{genotype component disconnectivity} (phenotypes consist of disconnected mutational networks) and shape space covering\textit{shape space covering} (most phenotypes can be reached in a small number of mutations). We also show that the mutational robustness of phenotypes scales very roughly logarithmically with phenotype redundancy and is positively correlated with phenotypic evolvability. Although our GP map describes the assembly of disconnected objects, it shares many properties with other popular GP maps for connected units, such as models for RNA secondary structure or the HP lattice model for protein tertiary structure. The remarkable fact that these important properties similarly emerge from such different models suggests the possibility that universal features underlie a much wider class of biologically realistic GP maps.Comment: 12 pages, 6 figure

    Peer Learning in Virtual Schools

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    This is the published version. Copyright 2014 Canadian Network for Innovation in EducationThis article is about peer-to-peer learning amongst students within K–12 virtual schools. This issue is examined through a case study of experiences of three students with disabilities enrolled in one virtual school and that of their parents, teachers, and school administrators. The article is framed around variability in learners’ aptitudes for peer-to-peer learning, in the design of the learning environment and what it affords for interpersonal interactions, and in the context where that learning design is implemented (and whether or not it promotes peer-to-peer learning). Each of these areas of variability impacted whether or not peer-to-peer learning occurred

    Just One More Chance

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    Photograph of Ruth Etting; Black waved illustration with green backgroundhttps://scholarsjunction.msstate.edu/cht-sheet-music/7815/thumbnail.jp

    Cocktails for Two

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    Illustration of a woman wearing a broad rimmed hat and hot pink lipstick advertising the film, Murder at the Vanities.https://scholarsjunction.msstate.edu/cht-sheet-music/2798/thumbnail.jp

    Effect of Moisture Content on Dust-Layer Dispersion Behind a Moving Shock Wave

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    PresentationSecondary dust explosions in coal mines or industrial settings are known to cause greater catastrophic hazards than the coupled primary explosions themselves. The shock waves produced during a primary explosion, which are initiated by inadvertent stimuli in an explosive atmosphere such as methane, lift surrounding coal particles from neighboring areas, and if added in an effort to create an inert mixture, limestone as well. This experimental study works with limestone dust, as its density is close to that of coal particles and its likely presence in the hazardous environment. The current study explored limestone moisture content to understand its effect on dust dispersion, which ultimately can influence the severity of a secondary explosion. A shock tube modified to evaluate dust dispersion provides the optical access to characterize the shock- wave / dust-layer interaction. Based on three shock Mach numbers, namely Ms = 1.1, 1.23, and 1.4, the trending data show an average increase of 10% in overall lifting heights and 20% in initial linear growth rates for the moisture-reduced, dried samples, as compared to undried samples stored in standard temperature and pressure (STP) conditions. Conceivably, the effective moisture reduction in the samples led to fewer agglomerations and/or reduced densities, influencing the ability of lift forces to act on the particles. The quantification of weight loss and weight differences between dried and undried samples was compared. The dust-layer rise height was measured with respect to time after the shock passage, where regardless of moisture content in the samples, initial dust growth rates increased with Mach number. Laminar and unstable regimes were also identified in the data samples, as seen in previous studies by the authors
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