388 research outputs found

    Pre-K in Texas: A Critical Component for Academic Success

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    With funding from the Meadows Foundation and the Miles Foundation, researchers at CHILDREN AT RISK engaged in a study to examine how participation in Texas public PreKindergarten Pre-K1 is associated with performance on the 3rd Grade State of Texas Assessment of Academic Readiness (STAAR) Reading assessment. CHILDREN AT RISK tracked approximately 47,000 students from the 2010-2011 school year to the 2014-2015 school year.2 These students began public Pre-K in 2010 and completed 3rd grade in 2015. The study focused on five major independent school districts (ISD) in Texas (Austin ISD, Dallas ISD, Fort Worth ISD, Houston ISD, and San Antonio ISD) and 12 additional school districts surrounding these major metropolitan areas.3 The purpose of this report is twofold. The first purpose is to educate parents, policy makers, and the public about the association between Texas public Pre-K and 3rd grade STAAR Reading outcomes. Across campuses and students, this study examines the relationship between varying levels of public Pre-K participation and STAAR Reading scores by comparing 3rd grade STAAR Reading means among multiple sub-groups of economically disadvantaged students. The second purpose is to offer policy recommendations that will increase access to and improve the quality of the Texas public Pre-K program on behalf of parents, taxpayers, and—most importantly—children

    Khovanov homotopy types and the Dold-Thom functor

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    We show that the spectrum constructed by Everitt and Turner as a possible Khovanov homotopy type is a product of Eilenberg-MacLane spaces and is thus determined by Khovanov homology. By using the Dold-Thom functor it can therefore be obtained from the Khovanov homotopy type constructed by Lipshitz and Sarkar

    A conjecture on Exceptional Orthogonal Polynomials

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    Exceptional orthogonal polynomial systems (X-OPS) arise as eigenfunctions of Sturm-Liouville problems and generalize in this sense the classical families of Hermite, Laguerre and Jacobi. They also generalize the family of CPRS orthogonal polynomials. We formulate the following conjecture: every exceptional orthogonal polynomial system is related to a classical system by a Darboux-Crum transformation. We give a proof of this conjecture for codimension 2 exceptional orthogonal polynomials (X2-OPs). As a by-product of this analysis, we prove a Bochner-type theorem classifying all possible X2-OPS. The classification includes all cases known to date plus some new examples of X2-Laguerre and X2-Jacobi polynomials

    Bayesian Parameter Estimation for Latent Markov Random Fields and Social Networks

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    Undirected graphical models are widely used in statistics, physics and machine vision. However Bayesian parameter estimation for undirected models is extremely challenging, since evaluation of the posterior typically involves the calculation of an intractable normalising constant. This problem has received much attention, but very little of this has focussed on the important practical case where the data consists of noisy or incomplete observations of the underlying hidden structure. This paper specifically addresses this problem, comparing two alternative methodologies. In the first of these approaches particle Markov chain Monte Carlo (Andrieu et al., 2010) is used to efficiently explore the parameter space, combined with the exchange algorithm (Murray et al., 2006) for avoiding the calculation of the intractable normalising constant (a proof showing that this combination targets the correct distribution in found in a supplementary appendix online). This approach is compared with approximate Bayesian computation (Pritchard et al., 1999). Applications to estimating the parameters of Ising models and exponential random graphs from noisy data are presented. Each algorithm used in the paper targets an approximation to the true posterior due to the use of MCMC to simulate from the latent graphical model, in lieu of being able to do this exactly in general. The supplementary appendix also describes the nature of the resulting approximation.Comment: 26 pages, 2 figures, accepted in Journal of Computational and Graphical Statistics (http://www.amstat.org/publications/jcgs.cfm

    Sexual Behavior of Bowhead Whales Observed Off the North Coast of Alaska

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    ... on 8 May 1976 approximately 32 km east of Point Barrow ... we observed and photographed a group of six bowhead whales engaged in sexual behavior in an open water "lead" in the pack ice. ... A series of 15, 35 mm photographs taken with a motor drive attachment provided a clear record of the observation. ... The aspect of each whale will be described as dorsal, lateral, or ventral, depending on which surface of the whale was toward the observer. ..

    Space-based research in fundamental physics and quantum technologies

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    Space-based experiments today can uniquely address important questions related to the fundamental laws of Nature. In particular, high-accuracy physics experiments in space can test relativistic gravity and probe the physics beyond the Standard Model; they can perform direct detection of gravitational waves and are naturally suited for precision investigations in cosmology and astroparticle physics. In addition, atomic physics has recently shown substantial progress in the development of optical clocks and atom interferometers. If placed in space, these instruments could turn into powerful high-resolution quantum sensors greatly benefiting fundamental physics. We discuss the current status of space-based research in fundamental physics, its discovery potential, and its importance for modern science. We offer a set of recommendations to be considered by the upcoming National Academy of Sciences' Decadal Survey in Astronomy and Astrophysics. In our opinion, the Decadal Survey should include space-based research in fundamental physics as one of its focus areas. We recommend establishing an Astronomy and Astrophysics Advisory Committee's interagency ``Fundamental Physics Task Force'' to assess the status of both ground- and space-based efforts in the field, to identify the most important objectives, and to suggest the best ways to organize the work of several federal agencies involved. We also recommend establishing a new NASA-led interagency program in fundamental physics that will consolidate new technologies, prepare key instruments for future space missions, and build a strong scientific and engineering community. Our goal is to expand NASA's science objectives in space by including ``laboratory research in fundamental physics'' as an element in agency's ongoing space research efforts.Comment: a white paper, revtex, 27 pages, updated bibliograph
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