284 research outputs found

    Some remarks on the spectral functions of the Abelian Higgs Model

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    We consider the unitary Abelian Higgs model and investigate its spectral functions at one-loop order. This analysis allows to disentangle what is physical and what is not at the level of the elementary particle propagators, in conjunction with the Nielsen identities. We highlight the role of the tadpole graphs and the gauge choices to get sensible results. We also introduce an Abelian Curci-Ferrari action coupled to a scalar field to model a massive photon which, like the non-Abelian Curci-Ferarri model, is left invariant by a modified non-nilpotent BRST symmetry. We clearly illustrate its non-unitary nature directly from the spectral function viewpoint. This provides a functional analogue of the Ojima observation in the canonical formalism: there are ghost states with nonzero norm in the BRST-invariant states of the Curci-Ferrari model.Comment: 32 pages, 12 figure

    Trends en scenarios's voor de natuurverkenning 2

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    Waar heeft het natuurbeleid de komende jaren rekening mee te houden? Diverse auteurs analyseren verwachte trends in verstedelijking, landbouw en bestuur en gaan na welke trends een positief effect kunnen hebben op natuur en landschap

    Natuurverkenning 2010-2040 : visies op de ontwikkeling van natuur en landschap

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    De Natuurverkenning verschijnt in een turbulente tijd waarin natuur en landschap sterk gepolitiseerd zijn. Met de verkenning wil het PBL een bijdrage leveren aan het structureren van het debat over de vernieuwing van het langetermijnbeleid en een impuls geven aan de politieke afwegingen. Nieuw is het gebruik van normatieve toekomstscenario’s als hulpmiddel om de achterliggende drijfveren voor natuurbeleid te verhelderen

    Onderzoek naar de chemische en microbiologische kwaliteit van zachte kaas

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    Voor Konsumenten Kontakt zijn in augustus en september 1992 zevenenveertig monsters zachte kaas (Brie en Camembert) chemisch en microbiologisch onderzocht. Het chemisch onderzoek bestond uit het bepalen van de gehaltes aan vocht en vet. Het microbiologische gedeelte bestond uit een onderzoek naar de aanwezigheid en/of het gehalte aan Staphy/ococcus aureus, Listeria monocytogenes en Escherichia coli

    Empathy in multiple sclerosis-correlates with cognitive, psychological and occupational functioning

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    Background Recent studies report deficits in social cognition in individuals with multiple sclerosis (MS). Social cognitive skills such as empathy are important for adequate social and occupational functioning. Our objectives are: (1) to examine whether empathy differs between individuals with MS and healthy controls, (2) to examine relations between empathy and cognitive, psychological and occupational functioning. Methods 278 individuals with MS (relapsing-remitting subtype) and 128 healthy controls from the MS@Work study participated in this investigation. The participants completed questionnaires about demographics, cognitive, psychological and occupational functioning, and underwent neurological and neuropsychological examinations. Mann-Whitney U-tests were used to examine group differences in empathy. Pearson and Spearman rank correlation analyses were used to examine relations between empathy and the other measures. Results Empathy did not differ between individuals with MS and healthy controls. In individuals with MS, higher empathy was correlated with a higher educational level (X2(df) = 13.2(2), p = 0.001), better verbal learning (r = 0.20, p = 0.001), less symptoms of depression (r=−0.21, p = 0.001), higher extraversion (r = 0.25, p ≤ 0.001), agreeableness (r = 0.55, p ≤ 0.001) and conscientiousness (r = 0.27, p ≤ 0.001) and better occupational functioning in terms of work scheduling and output demands (r = 0.23, p = 0.002) and less cognitive/psychological work barriers (r = −0.21, p = 0.001). In healthy controls, higher empathy was correlated with less symptoms of depression (r = −0.34, p ≤ 0.001), less fatigue (r = −0.37, p ≤ 0.001), higher agreeableness (r = 0.59, p ≤ 0.001) and better occupational functioning in terms of work ability as compared to lifetime best (r = 0.28, p = 0.001) and less cognitive/psychological work barriers (r = −0.34, p ≤ 0.001). Empathy did not differ between unemployed and employed individuals with MS or healthy controls. Conclusion Empathy did not differ between individuals with MS and healthy controls. Within both investigated groups, higher empathy was weakly to moderately correlated with less symptoms of depression, higher agreeableness and better occupational functioning. We also found unique correlations for empathy within the investigated groups. Longitudinal studies are needed to further examine social cognition in relation to cognitive, psychological and occupational functioning in both individuals with MS and healthy controls. It would be particularly interesting to concurrently examine changes in the brain network involved with social cognition

    Ecological risk assessment of endocrine disruptors.

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    The European Centre for Ecotoxicology and Toxicology of Chemicals proposes a tiered approach for the ecological risk assessment of endocrine disruptors, integrating exposure and hazard (effects) characterization. Exposure assessment for endocrine disruptors should direct specific tests for wildlife species, placing hazard data into a risk assessment context. Supplementing the suite of mammalian screens now under Organization for Economic Cooperation and Development (OECD) validation, high priority should be given to developing a fish screening assay for detecting endocrine activity in oviparous species. Taking into account both exposure characterization and alerts from endocrine screening, higher tier tests are also a priority for defining adverse effects. We propose that in vivo mammalian and fish assays provide a comprehensive screening battery for diverse hormonal functions (including androgen, estrogen, and thyroid hormone), whereas Amphibia should be considered at higher tiers if there are exposure concerns. Higher tier endocrine-disruptor testing should include fish development and fish reproduction tests, whereas a full life-cycle test could be subsequently used to refine aquatic risk assessments when necessary. For avian risk assessment, the new OECD Japanese quail reproduction test guideline provides a valuable basis for developing a test to detecting endocrine-mediated reproductive effects; this species could be used, where necessary, for an avian life-cycle test. For aquatic and terrestrial invertebrates, data from existing developmental and reproductive tests remain of high value for ecological risk assessment. High priority should be given to research into comparative endocrine physiology of invertebrates to support data extrapolation to this diverse fauna

    Self-reported work productivity in people with multiple sclerosis and its association with mental and physical health

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    PURPOSE: This study aimed to identify mental health, physical health, demographic and disease characteristics relating to work productivity in people with multiple sclerosis (MS). METHODS: In this cross-sectional study, 236 employed people with MS (median age = 42 years, 78.8% female) underwent neurological and neuropsychological assessments. Additionally, they completed questionnaires inquiring about work productivity (presenteeism: reduced productivity while working, and absenteeism: loss of productivity due to absence from work), mental and physical health, demographic and disease characteristics. Multiple linear and logistic regression analyses were performed with presenteeism and absenteeism as dependent variables, respectively. RESULTS: A model with mental and physical health factors significantly predicted presenteeism F(11,202) = 11.33, p < 0.001, R2 = 0.38; a higher cognitive (p < 0.001) and physical impact (p = 0.042) of fatigue were associated with more presenteeism. A model with only mental health factors significantly predicted absenteeism; χ2(11)=37.72, p < 0.001, with R2 = 0.27 (Nagelkerke) and R2 = 0.16 (Cox and Snell). Specifically, we observed that more symptoms of depression (p = 0.041) and a higher cognitive impact of fatigue (p = 0.011) were significantly associated with more absenteeism. CONCLUSIONS: In people with MS, both cognitive and physical impact of fatigue are positively related to presenteeism, while symptoms of depression and cognitive impact of fatigue are positively related to absenteeism.Implications for rehabilitationMultiple sclerosis (MS) affects people of working age, significantly interfering with work productivity.Higher cognitive and physical impact of fatigue were associated with more presenteeism in workers with MS.A higher cognitive impact of fatigue and more depressive symptoms were associated with absenteeism in workers with MS.Occupational and healthcare professionals should be aware of the impact of both physical and mental health on work productivity in workers with MS
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