1,687 research outputs found

    Maxitive functions with respect to general orders

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    In decision-making, maxitive functions are used for worst-case and best-case evaluations. Maxitivity gives rise to a rich structure that is well-studied in the context of the pointwise order. In this article, we investigate maxitivity with respect to general preorders and provide a representation theorem for such functionals. The results are illustrated for different stochastic orders in the literature, including the usual stochastic order, the increasing convex/concave order, and the dispersive order

    The association of positive psychological factors with work ability one year after myocardial infarction

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    Background Positive psychological factors like optimism, resilience and self-efficacy may facilitate successful adjustment after hospitalization for myocardial infarction (MI) and treatment with percutaneous coronary intervention (PCI), including return to work. Objective To examine whether positive psychological factors (optimism, resilience, and self-efficacy) predict work ability one year after PCI for MI. Methods Patients treated with PCI and with paid employment were included and completed questionnaires at 1 and 12 months post PCI discharge. Patients filled out the LOT-R optimism scale, the dispositional resilience scale (DRS-15), and the Cardiac Self-efficacy Scale (CSE) at 1-month, and the work ability index (WAI) at 1-year follow-up. Hierarchical linear regression models were used. Sensitivity analysis was performed for the acuteness of the PCI treatment. Results In total, 323 patients (14% women; mean age 59.5 ± 6.8y; 74% acute PCI) completed both surveys. At 1-year follow-up, resilience (β = 0.152, p = 0.009) and cardiac self-efficacy (β = 0.273, p < 0.001), but not optimism (β = 0.044, p = 0.432), were associated with work ability at 1 year, irrespective of cardiac history, or sex. Age (β = −0.158, p = 0.002) and comorbidity index (β = −0.104, p = 0.044) were significant covariates. Sensitivity analysis revealed that in patients receiving an elective Conclusion Resilience and cardiac self-efficacy were independently associated with work ability 1 year post PCI, whereas optimism was not. Identification and support of patients low in cardiac self-efficacy and resilience may contribute to improved restoration of work ability post PCI

    Het meten van kennisdoorwerking : meten van de doorwerking van onderzoekskennis in de biologische landbouw : onderzoeksproject "dierenwelzijn in de biologische melkveehouderij"

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    Het project “Kennisbenutting in de Biologische Landbouw” ontwikkelt een methode voor het meten van de doorwerking van onderzoekskennis in de biologische praktijk. Tegelijk met het ontwikkelen wordt de methode toegepast in verschillende pilots. Zo wordt de aanpak ontwikkeld, toegepast en getest. Deze pilot gaat over onderzoek naar dierenwelzijn in de biologische melkveehouderij (koeien). Het betreft hier een groep van projecten die in een periode van ongeveer vier jaar zijn uitgevoerd. Welzijn van dieren heeft uiteenlopende aspecten die vaak in afzonderlijke projecten zijn onderzocht. In de praktijk van het boerenbedrijf moet de ondernemer een keuze maken hoe hij de diverse welzijnsaspecten met elkaar combineert om tot een aanpak voor zijn eigen bedrijf te komen. De complexiteit van deze casus is dan ook de vertaling van een brede projectenportfolio naar meetbare benutting in de bedrijfspraktijk

    Parental cooperation in an extreme hot environment: natural behaviour and experimental evidence

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    One of the most apparent examples of cooperation between unrelated individuals is biparental care whereby the male and the female parent share the rearing of the offspring. Theoretical models of care predict that selection should favour biparental care if it substantially improves the survival of the offspring. Although various ecological factors have been proposed to necessitate biparental care, experimental evidence is scant given the challenges of manipulating ecological factors in the natural habitat of animals. We carried out one such experiment in a small shorebird, the Kentish plover, Charadrius alexandrinus, that breeds in an extreme desert environment. Nest cover and thus exposure to solar radiation vary between nests, and we show that parents at exposed nests spent more time incubating than those at nests shaded by a bush (covered nests). Experimental removal and supplementation of nest cover gave results consistent with the observational data; at experimentally exposed nests both males and females increased incubation effort and relieved each other more frequently whereas at experimentally covered nests we observed the opposite. We conclude that exposure to extreme solar radiation influences biparental care and this necessitates parental cooperation in the Kentish plover. Furthermore, since parental care often coevolves with mating strategies, we conjecture that where the environment puts less pressure on the parents and provides the opportunity for reduced care, both mating systems and parental care can diversify over evolutionary time. (C) 2011 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved

    Het meten van kennisdoorwerking : meten van de doorwerking van onderzoekskennis in de biologische landbouw : onderzoeksproject "mechanische onkruidbestrijding"

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    Het project “Kennisbenutting in de Biologische Landbouw” ontwikkelt een methode voor het meten van de doorwerking van onderzoekskennis in de biologische praktijk. Tegelijk met het ontwikkelen wordt de methode toegepast in verschillende pilots. Zo wordt de aanpak ontwikkeld, toegepast en getest. Deze pilot gaat over onderzoek naar mechanische onkruidbestrijding in de biologische landbouw. Het gaat hier om een groep van projecten die in een periode van vier jaar zijn uitgevoerd. In deze casus is een essentiële intermediaire partij aanwezig tussen onderzoek en praktijk, namelijk de machinefabrikanten. De praktijkcontext is tamelijk complex door de variatie in cultuurgewassen, grondsoorten, onkruiden en bedrijfsomvang

    A systematic review comparing two popular methods to assess a Type D personality effect

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    Introduction:  Type D personality, operationalized as high scores on negative affectivity (NA) and social inhibition (SI), has been associated with various medical and psychosocial outcomes. The recent failure to replicate several earlier findings could result from the various methods used to assess the Type D effect. Despite recommendations to analyze the continuous NA and SI scores, a popular approach groups people as having Type D personality or not. This method does not adequately detect a Type D effect as it is also sensitive to main effects of NA or SI only, suggesting the literature contains false positive Type D effects. Here, we systematically assess the extent of this problem. Method:  We conducted a systematic review including 44 published studies assessing a Type D effect with both a continuous and dichotomous operationalization. Results:  The dichotomous method showed poor agreement with the continuous Type D effect. Of the 89 significant dichotomous method effects, 37 (41.6%) were Type D effects according to the continuous method. The remaining 52 (58.4%) are therefore likely not Type D effects based on the continuous method, as 42 (47.2%) were main effects of NA or SI only. Conclusion:  Half of the published Type D effect according to the dichotomous method may be false positives, with only NA or SI driving the outcome

    Qualitative and quantitative analysis of stability and instability dynamics of positive lattice solitons

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    We present a unified approach for qualitative and quantitative analysis of stability and instability dynamics of positive bright solitons in multi-dimensional focusing nonlinear media with a potential (lattice), which can be periodic, periodic with defects, quasiperiodic, single waveguide, etc. We show that when the soliton is unstable, the type of instability dynamic that develops depends on which of two stability conditions is violated. Specifically, violation of the slope condition leads to an amplitude instability, whereas violation of the spectral condition leads to a drift instability. We also present a quantitative approach that allows to predict the stability and instability strength
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