643 research outputs found

    The minimum vertex degree for an almost-spanning tight cycle in a 33-uniform hypergraph

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    We prove that any 33-uniform hypergraph whose minimum vertex degree is at least (59+o(1))(n2)\left(\frac{5}{9} + o(1) \right)\binom{n}{2} admits an almost-spanning tight cycle, that is, a tight cycle leaving o(n)o(n) vertices uncovered. The bound on the vertex degree is asymptotically best possible. Our proof uses the hypergraph regularity method, and in particular a recent version of the hypergraph regularity lemma proved by Allen, B\"ottcher, Cooley and Mycroft.Comment: 10 pages. arXiv admin note: text overlap with arXiv:1411.495

    State Land Policy in Alaska: Progress and Prospects

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    New Records of Michigan Cicadidae (Homoptera), With Notes on the Use of Songs to Monitor Range Changes

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    We present records of Diceroprocta vitripennis, Tibicen chloromera, and Tibicen pruinosa (new state record) in Michigan. Monitoring geographic range changes and population size differences by song suggests several population situations for cicadas: (1) sizable populations in most areas of apparently good habitat; (2) widely separated single individuals or small populations on the edges of populated regions, representing range extensions that may be of limited duration; (3) one or a few individuals present only once, probably transferred in soil on roots, and ultimately unsuccessful. Species- specific calling songs allow sensitive measurement of species\u27 range changes

    Downscaling extremes: A comparison of extreme value distributions in point-source and gridded precipitation data

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    There is substantial empirical and climatological evidence that precipitation extremes have become more extreme during the twentieth century, and that this trend is likely to continue as global warming becomes more intense. However, understanding these issues is limited by a fundamental issue of spatial scaling: most evidence of past trends comes from rain gauge data, whereas trends into the future are produced by climate models, which rely on gridded aggregates. To study this further, we fit the Generalized Extreme Value (GEV) distribution to the right tail of the distribution of both rain gauge and gridded events. The results of this modeling exercise confirm that return values computed from rain gauge data are typically higher than those computed from gridded data; however, the size of the difference is somewhat surprising, with the rain gauge data exhibiting return values sometimes two or three times that of the gridded data. The main contribution of this paper is the development of a family of regression relationships between the two sets of return values that also take spatial variations into account. Based on these results, we now believe it is possible to project future changes in precipitation extremes at the point-location level based on results from climate models.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS287 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Tight cycles in hypergraphs

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    We apply a recent version of the Strong Hypergraph Regularity Lemma(see [1], [2]) to prove two new results on tight cycles in k-uniform hypergraphs. The first result is an extension of the Erdos-Gallai Theorem for graphs: For every > 0, every sufficiently large k-uniform hypergraph on n vertices with at least edges contains a tight cycle of length @n for any @ 2 [0; 1]. Our second result concerns k-partite k-uniform hypergraphs with partition classes of size n and for each @ 2 (0; 1) provides an asymptotically optimal minimum codegree requirement for the hypergraph to contain a cycle of length @kn

    Regular slices for hypergraphs

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    We present a ‘Regular Slice Lemma’ which, given a k -graph GG, returns a regular (k−1)(k−1)-complex JJ with respect to which GG has useful regularity properties. We believe that many arguments in extremal hypergraph theory are made considerably simpler by using this lemma rather than existing forms of the Strong Hypergraph Regularity Lemma, and advocate its use for this reason

    Parasitic infection surveillance in Mississippi delta children

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    Some recent studies suggest ongoing transmission of parasitic diseases in the American South; however, surveys in Mississippi children are lacking. We enrolled 166 children (median age 8 years, range 4–13 years) from the Mississippi Delta region and carried out multi-parallel real-time polymerase chain reaction (PCR) for Necator americanus, Ascaris lumbricoides, and Strongyloides stercoralis on their stool samples. Dried blood spots were obtained for multiplex serology antibody detection. Of 166 children, all reported having flushable toilets, 11% had soil exposure, and 34% had a pet dog or cat. None had prior diagnosis or treatment of parasitic disease. Multi-parallel real-time PCRs were negative on the 89 stool DNA extracts available for testing. Dried blood spot testing of all 166 children determined the seroprevalence of IgG antibodies to Toxocara spp. (3.6%), Cryptosporidium (2.4%), S. stercoralis, Fasciola hepatica, and Giardia duodenalis (all 0%). In conclusion, parasitic infections and exposure were scarce in this population. Larger studies of at-risk populations are needed. © 2020 by The American Society of Tropical Medicine and Hygiene. ***Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Richard Bradbury ” is provided in this record***This work was funded by the Centers for Disease Control and Prevention (RSB), the Blakeslee Fund for Genetics Research at Smith College (N. P. and S. A. W.), and the University of Mississippi Medical Center (Office of the Vice Chancellor for Research, the University of Mississippi Medical Center). R. B. reports a patent WO2019060840 “Removing Interfering Host NucleicAcids for Molecular Parasite Detection” with royalties paid to Centers for Disease Control and Prevention. This trial was observational and is exempt from registration at clinicaltrials.gov Disclaimer: The findings and conclusions of this work are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention/the Agency for Toxic Substances and Disease Registry. This work was presented at the American Society of Tropical Medicine and Hygiene Conference: Poster 522, October 28–November 1, New Orleans, L

    Parasitic disease surveillance, Mississippi, USA

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    Surveillance for soil-transmitted helminths, strongyloidiasis, cryptosporidiosis, and giardiasis was conducted in Mississippi, USA. PCR performed on 224 fecal samples for all soil-transmitted helminths and on 370 samples for only Necator americanus and Strongyloides stercoralis identified 1 S. stercoralis infection. Seroprevalences were 8.8% for Toxocara, 27.4% for Cryptosporidium, 5.7% for Giardia, and 0.2% for Strongyloides parasites. © 2021 Centers for Disease Control and Prevention (CDC). All rights reserved. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Richard Bradbury" is provided in this record*
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