منابع مشابه
A Tame Cantor Set
A Cantor set is a non-empty, compact set that has neither interior nor isolated points. In this paper a Cantor set K ⊆ R is constructed such that every set definable in (R, <,+, ·,K) is Borel. In addition, we prove quantifierelimination and completeness results for (R, <,+, ·,K), making the set K the first example of a modeltheoretically tame Cantor set. This answers questions raised by Friedma...
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We have conducted the first study of sleep in the platypus Ornithorhynchus anatinus. Periods of quiet sleep, characterized by raised arousal thresholds, elevated electroencephalogram amplitude and motor and autonomic quiescence, occupied 6-8 h/day. The platypus also had rapid eye movement sleep as defined by atonia with rapid eye movements, twitching and the electrocardiogram pattern of rapid e...
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STEP is an ISO standard (ISO-10303) for the computer-interpretable representation and exchange of product data. Parts of STEP standardize conceptual structures and usage of information in generic or specific domains. The standardization process of these constructs is an approach which can be applied to a data-based integration. Platypus is a STEP-based meta-environment. From the data integratio...
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For over two centuries, the platypus (Ornithorhynchus anatinus) has been constructed and categorized in multiple ways. An unprecedented mélange of anatomical features and physiological functions, it long remained a systematic quandary. Nevertheless, since 1797, naturalists and biologists have pursued two recurring obsessions. Investigations into platypus reproduction and lactation have focused ...
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ژورنال
عنوان ژورنال: Nature
سال: 1935
ISSN: 0028-0836,1476-4687
DOI: 10.1038/135875b0