397 research outputs found

    Induced Ramsey-type results and binary predicates for point sets

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    Let kk and pp be positive integers and let QQ be a finite point set in general position in the plane. We say that QQ is (k,p)(k,p)-Ramsey if there is a finite point set PP such that for every kk-coloring cc of (Pp)\binom{P}{p} there is a subset QQ' of PP such that QQ' and QQ have the same order type and (Qp)\binom{Q'}{p} is monochromatic in cc. Ne\v{s}et\v{r}il and Valtr proved that for every kNk \in \mathbb{N}, all point sets are (k,1)(k,1)-Ramsey. They also proved that for every k2k \ge 2 and p2p \ge 2, there are point sets that are not (k,p)(k,p)-Ramsey. As our main result, we introduce a new family of (k,2)(k,2)-Ramsey point sets, extending a result of Ne\v{s}et\v{r}il and Valtr. We then use this new result to show that for every kk there is a point set PP such that no function Γ\Gamma that maps ordered pairs of distinct points from PP to a set of size kk can satisfy the following "local consistency" property: if Γ\Gamma attains the same values on two ordered triples of points from PP, then these triples have the same orientation. Intuitively, this implies that there cannot be such a function that is defined locally and determines the orientation of point triples.Comment: 22 pages, 3 figures, final version, minor correction

    Vitamin D Deficiency and Myocardial Dysfunction

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    Potenzial entomopathogener Pilze zur Kontrolle des Rapsglanzkäfers

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    Fungal isolates of Beauveria bassiana (21 isolates), B. brongniartii (2), Paecilomyces fumosoroseus (1) and Metarhizium anisopliae (1) were screened for virulence against pollen beetle Meligethes aeneus. Most of the tested B. bassiana isolates originated from naturally infected pollen beetles collected in Switzerland. In a lab bioassay adult beetles were dipped into a defined conidial suspension and fungal infection was recorded after 15 days. Seven isolates of B. bassiana as well as the P. fumosoroseus F4K caused infection rates between 67.9% and 80% respectively and proved to be promising strains for potential use against pollen beetles. However, more experiments are needed to confirm their biological control potential under field conditions

    Advanced Techniques in Mortality Trend Estimation: Integrating Generalized Additive Models and Machine Learning to Evaluate the COVID-19 Impact

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    The last two centuries have seen a significant increase in life expectancy. Although past trends suggest that mortality will continue to decline in the future, uncertainty and instability about the development is greatly increased due to the ongoing COVID-19 pandemic. It is therefore of essential interest, particularly to annuity and life insurers, to predict the mortality of their members or policyholders with reliable accuracy. The goal of this study is to improve the state-of-the-art stochastic mortality models using machine learning techniques and generalize them to a multi-population model. Detailed cross-country results conducted for Finland, Germany, Italy, the Netherlands, and the United States show that the best forecasting performance is achieved by a generalized additive model that uses the framework of APC analysis. Based on this finding, trend forecasts of mortality rates as a measure of longevity are fulfilled for the future, given a range of COVID-19 scenarios, from mild to severe. Discussing and evaluating the plausibility of these scenarios, this study is useful for preparation, planning, and informed decision-making

    Lebensdauermodelle mit flexibler Hazardrate

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    Vitamin D supplementation after the menopause

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    The purpose of this review was to assess recent evidence regarding the effects of low vitamin D levels on some highly prevalent clinical conditions of postmenopausal women. We reviewed and selected recent literature regarding menopause-related conditions associated with vitamin D deficiency and interventions to manage them. Low circulating 25-hydroxyvitamin D (25(OH)D) levels related to menopause are linked to diet, lifestyle, changes in body composition, insulin sensitivity, and reduced physical activity. Vitamin D supplementation increases serum 25(OH)D levels while normalizing parathyroid hormone and bone markers, and in women with serum 25(OH)D levels below 10 ng/ml supplementation may improve bone mineral density. Low vitamin D status has been associated with the metabolic syndrome, high triglyceride levels, and low high-density lipoprotein cholesterol levels. When compared with placebo, vitamin D supplementation may lower the risk of the metabolic syndrome, hypertriglyceridemia, and hyperglycemia. There is an inverse relationship between fat mass and serum 25(OH)D levels and, therefore, the dosage of supplementation should be adjusted according to the body mass index. Although vitamin D supplementation may improve glucose metabolism in prediabetic subjects, data regarding muscle strength are conflictive. There is evidence that vitamin D over-treatment, to reach extremely high circulating 25(OH)D levels, does not result in better clinical outcomes. The identification and treatment of vitamin D deficiency in postmenopausal women may improve their general health and health outcomes. Vitamin D supplementation should preferably be based on the use of either cholecalciferol or calcifediol
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