19 research outputs found

    Move blocking strategies in receding horizon control

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    Abstract — In order to deal with the computational burden of optimal control, it is common practice to reduce the degrees of freedom by fixing the input or its derivatives to be constant over several time-steps. This policy is referred to as “move blocking”. This paper will address two issues. First, a survey of various move blocking strategies is presented and the shortcomings of these blocking policies, such as the lack of stability and constraint satisfaction guarantees, will be illustrated. Second, a novel move blocking scheme, “Moving Window Blocking” (MWB), will be presented. In MWB, the blocking strategy is time-dependent such that the scheme yields stability and feasibility guarantees for the closed-loop system. Finally, the results of a large case-study are presented that illustrate the advantages and drawbacks of the various control strategies discussed in this paper

    Delineation of Culicoides species by morphology and barcode exemplified by three new species of the subgenus Culicoides (Diptera: Ceratopogonidae) from Scandinavia

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    BACKGROUND: Culicoides biting midges (Diptera: Ceratopogonidae) cause biting nuisance to livestock and humans and are vectors of a range of pathogens of medical and veterinary importance. Despite their economic significance, the delineation and identification of species where only morphology is considered, as well as the evolutionary relationships between species within this genus remains problematic. In recent years molecular barcoding has assisted substantially in the identification of biting midges in the multiple entomological survey projects which were initiated in many European countries following the bluetongue outbreak in 2006–2009. These studies revealed potentially new species and “species-complexes” with large genetic and morphological variability. Here we use molecular barcoding, together with morphological analysis, to study subgenus Culicoides Latreille from Scandinavia with focus on three potentially new species. METHODS: Biting midges were collected at various sites in Denmark and Sweden. Culicoides specimens were described by variation of a fragment of their cytochrome c oxidase subunit 1 (COI) gene sequence and wing, palp and antennal characters. RESULTS: It is shown that three new species initially separated by DNA barcoding with mitochondrial COI can be distinguished by morphological characters. In this context a key to Scandinavian subgenus Culicoides using wing and maxillary palp characters is presented. The key is including the three new species Culicoides boyi, Culicoides selandicus and Culicoides kalix. CONCLUSION: Three new species of Culicoides biting midges were identified and could be identified by both molecular and morphological differences. Evaluation of differences between and within taxa of biting midges using COI barcode yielded a rough estimate of species delineation; interspecies differences across Culicoides subgenera approaches 20%, whereas intraspecies differences are below 4% and in most cases below 1%. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13071-015-0750-4) contains supplementary material, which is available to authorized users

    A power measure analysis of Amendment 36 in Colorado

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    Colorado’s Amendment 36 proposed to switch Colorado’s representation in the Electoral College from winner-takes-all to proportionality. We evaluate unilateral and uniform switches to proportionality both from Colorado’s perspective and from an impartial perspective on the basis of a priori and a posteriori voting power measures. The present system is to be preferred to a unilateral switch from any perspective on any measure. A uniform switch is to be preferred to the present system from Colorado’s perspective on an a priori measure, and from an impartial perspective on an a posteriori measure. The present system is to be preferred to a uniform switch from Colorado’s perspective on an a posteriori measure (with some qualifications), and from an impartial perspective on an a priori measure. We conclude with a discussion of the appropriateness of these measures

    Anaplasmose in einem Milchviehbetrieb in GraubĂźnden: Epidemiologische Ausbruchsuntersuchung

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    In summer of 2002, a case of severe clinical bovine anaplasmosis caused great losses in a dairy farm of an animal trader in Grisons. This article outlines the general approach of an outbreak investigation considering the case of anaplasmosis as an example. The goals of such investigations are to identify and eliminate the source of a disease outbreak in order to avoid additional cases. In addition, recommendations should be developed for preventing or limiting the magnitude of similar outbreaks in the future. In the outbreak presented, the causative agents were probably brought into the dairy farm by animal trade. Due to the large herd size, a missing quarantine for new animals and the coinfection with several pathogens, this case led to a high number of fatalities. The investigations of this outbreak demonstrated the importance of an universal and consistent identification of individual animals for the reconstruction of their movements. The veterinary practitioner should be reminded to act cautiously when facing strange clinical cases and to also consider "exotic diseases" as a possible cause
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