5,077 research outputs found

    The Bees of A.L. Mangham Jr. Regional Airport, Nacogdoches, Texas

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    The United States is home to about 4,000 species of native bees, and many are critically important due to the pollination services they provide (Buchman & Nabhan 1996). Most of these are inconspicuous, solitary bees that nest in the ground. In recent years, a number of bee species have been shown to be in decline (Burkle 2013). Due to these declines, it is important to study and provide habitat for local bee populations. As a result of periodic mowing, the surroundings of the A.L. Mangham Jr. Regional Airport in Nacogdoches County, Texas provide a grassy, prairie-like habitat that results in a high diversity of wildflowers. This site may contain high bee diversity as well. In order to explore this possibility, a survey of bees at this location was conducted in the late summer and fall of 2016

    An Assessment of Uncertainty in Atmospheric State Measurements on Airborne Platforms

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    Several federal agencies, including NASA, maintain a fleet of highly specialized research aircraft which are routinely used in airborne science field studies. Well characterized measurements of atmospheric state parameters, such as pressure, ambient temperature, and wind speed are paramount in the ability to perform higher level analysis towards complex research questions. Even though measurements have been made over several decades, they remain a challenge given the compressibility of air along the aircraft axis, instrument placement along the aircraft skin, and the potential for probe contamination. Therefore, a set of redundant measurements is often acquired to ensure a complete instrument time series. This uncertainty assessment takes advantage of various inter-comparison techniques devised to diagnose the temporal and spatial fidelity of atmospheric state parameters, often between different instrumentation sources and aircraft assets. To be discussed are the impacts of this ongoing study, current limitations to the airborne probes, and plans for future work

    Uncertainty benchmarks for time-dependent transport problems

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    Uncertainty quantification results are presented for a well known verification solution, the time dependent transport infinite plane pulse. The method of polynomial chaos expansions (PCE) is employed for quick and accurate calculation of the quantities of interest. Also, the method of uncollided solutions is used in this problem to treat part of the uncertainty calculation analytically

    Generalized Ramsey numbers at the linear and quadratic thresholds

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    The generalized Ramsey number f(n,p,q)f(n, p, q) is the smallest number of colors needed to color the edges of the complete graph KnK_n so that every pp-clique spans at least qq colors. Erd\H{o}s and Gy\'arf\'as showed that f(n,p,q)f(n, p, q) grows linearly in nn when pp is fixed and q=qlin(p):=(p2)−p+3q=q_{\text{lin}}(p):=\binom p2-p+3. Similarly they showed that f(n,p,q)f(n, p, q) is quadratic in nn when pp is fixed and q=qquad(p):=(p2)−p2+2q=q_{\text{quad}}(p):=\binom p2-\frac p2+2. In this note we improve on the known estimates for f(n,p,qlin)f(n, p, q_{\text{lin}}) and f(n,p,qquad)f(n, p, q_{\text{quad}}). Our proofs involve establishing a significant strengthening of a previously known connection between f(n,p,q)f(n, p, q) and another extremal problem first studied by Brown, Erd\H{o}s and S\'os, as well as building on some recent progress on this extremal problem by Delcourt and Postle and by Shangguan. Also, our upper bound on f(n,p,qlin)f(n, p, q_{\text{lin}}) follows from an application of the recent forbidden submatchings method of Delcourt and Postle.Comment: 16 page

    Morphological and molecular characterisation of a mixed Cryptosporidium muris/Cryptosporidium felis infection in a cat

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    To date Cryptosporidium muris has been identified by microscopy and genotyping in cats in two studies. We report morphological and genetic evidence of a mixed C. muris and C. felis infection in a cat and provide the first histological, immunohistochemical, in situ hybridisation and genetic confirmation of a C. muris infection in the stomach of a cat. The cat suffered persistent diarrhoea after the initial consultation, which remained unresolved, despite several medical interventions. Further studies are required to determine the range, prevalence and clinical impact of Cryptosporidium species infecting cats
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