Exact algorithms for detecting all rotational and involutional symmetries in point sets, polygons and polyhedra are described. The time complexities of the algorithms are shown to be O(n) for polygons and O(nlogn) for two-and three-dimensional point sets. O(n logn) time is also required for general polyhedra, but for polyhedra with connected, planar surface graphs O(n) time canbe achieved. All algorithms are optimal in time complexity, within constants.
In 2014, infectious spleen and kidney necrosis virus (ISKNV), a member of the genus Megalocytivirus, was detected for the first time in ornamental fish in Germany. Since 2013, angelfish Pterophyllum spp. originating from Colombia have experienced significant epizootics in a number of German retailers' facilities. The diseased fish showed symptoms such as increased ventilation, swollen gills, and ulcerations of the skin. In 2014, diseased angelfish P. altum and platys Xiphophorus maculatus maintained in the same recirculating system were examined. Histopathological lesions included hypertrophic cells, single-cell necrosis, and an inflammatory infiltration of granulocytes, lymphocytes, and macrophages in liver, spleen, and kidney. Transmission electron microscopy revealed the presence of numerous poly gonal viral particles (150 nm in diameter) within the cytoplasm of enlarged cells. A PCR assay for the detection of megalocytiviruses amplified 777 bp of major capsid protein gene that was 100% identical to ISKNV. This is the first report of an ISKNV outbreak in Germany that most probably was introduced by infected angelfish from Colombia. To our knowledge, this is the first report of ISKNV detected in fish imported from South America. Given the lethal nature of megalocytiviruses, proper biosecurity would seem prudent in countries like Germany where these emerging pathogens are not established.
Robot S y s t e m s Division C e n t e r for Research on I n t e g r a t e d M a n u f a c t u r i n g University of MichiganAbstract: The problem of generating plans for ihe manufacture of assemblies differs zn imporiani respects f r o m ihe Yblock world" robot planning problems that have been studied in A I In mass production applications, a worksite is normally configured specifically for each task, so ihe layout of the workspace and the tniiial configuration of ihe parts musi be ireated as outpuis of the plannrng process, raiher ihan as inputs A sysiem to solve such problems must be capable of reasoning about a large varieiy of part insertion irajeciories and musi be able io opiimize wiih respeci to compler, appltcatzon-dependent sets of criieria This paper will iniroduce the assembly planning problem and describe an ezperimental assembly planning system which IS capable of rapldly generating plans for most assemblies
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