7,914 research outputs found

    Preen Gland-Secreted Alkanols Enhance Male Attractiveness in Parrots

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    The skin glands are widely used in pheromone production throughout the vertebrate worlds. Growing evidences show that birds also have chemical communication, but the uropygial (also called preen or oil) glands, serving as only specialized skin glands of birds, have no sex pheromones characterized. Here, by combining GC-MS analysis and bioassay, we show with the budgerigar, Melopsittacus undulatus, that birds can used the preen gland-secreted volatiles (a blend of octadecanol, nonadecanol and eicosanol for male budgerigars) spread over body plumage when preening to convey sex information. Here, we first report the avian pheromones derived from the uropyginal gland and suggests that the gland has broader implications than previously known (e.g. plumage waterproofing and reflectance in sexual behaviour of birds

    Analytic smoothness effect of solutions for spatially homogeneous Landau equation

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    In this paper, we study the smoothness effect of Cauchy problem for the spatially homogeneous Landau equation in the hard potential case and the Maxwellian molecules case. We obtain the analytic smoothing effect for the solutions under rather weak assumptions on the initial datum.Comment: 16 page

    A Continuously Growing Dataset of Sentential Paraphrases

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    A major challenge in paraphrase research is the lack of parallel corpora. In this paper, we present a new method to collect large-scale sentential paraphrases from Twitter by linking tweets through shared URLs. The main advantage of our method is its simplicity, as it gets rid of the classifier or human in the loop needed to select data before annotation and subsequent application of paraphrase identification algorithms in the previous work. We present the largest human-labeled paraphrase corpus to date of 51,524 sentence pairs and the first cross-domain benchmarking for automatic paraphrase identification. In addition, we show that more than 30,000 new sentential paraphrases can be easily and continuously captured every month at ~70% precision, and demonstrate their utility for downstream NLP tasks through phrasal paraphrase extraction. We make our code and data freely available.Comment: 11 pages, accepted to EMNLP 201

    The Gevrey Hypoellipticity for linear and non-linear Fokker-Planck equations

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    In this paper, we study the Gevrey regularity of weak solution for a class of linear and quasilinear Fokker-Planck equations
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