2,052 research outputs found

    Non elliptic SPDEs and ambit fields: existence of densities

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    Relying on the method developed in [debusscheromito2014], we prove the existence of a density for two different examples of random fields indexed by (t,x)\in(0,T]\times \Rd. The first example consists of SPDEs with Lipschitz continuous coefficients driven by a Gaussian noise white in time and with a stationary spatial covariance, in the setting of [dalang1999]. The density exists on the set where the nonlinearity σ\sigma of the noise does not vanish. This complements the results in [sanzsuess2015] where σ\sigma is assumed to be bounded away from zero. The second example is an ambit field with a stochastic integral term having as integrator a L\'evy basis of pure-jump, stable-like type.Comment: 23 page

    Functional foods with added plant sterols for treatment of hypercholesterolaemia and prevention of ischaemic heart disease

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    Background. A spread with added plant sterols, Pro-activ, is marketed in South Africa as an adjunct to low-fat diets for lowering of total and low-density lipoprotein (LDL) cholesterol concentrations and to decrease risk of ischaemic heart disease (IHD). Objectives. The need for this functional food in South Africa, its efficacy, safety and target market, are evaluated in this review. Results. The high, and probably increasing incidence of hypercholesterolaemia and cardiovascular disease in South Africa motivates the need for appropriate functional foods. There is convincing evidence in the literature that an average daily intake of about 2 g plant sterols in about 20 g of spread significantly lowers total and LDL cholesterol concentrations by approximately 10 - 15%, without influencing high-density lipoprotein (HDL) cholesterol and triglyceride concentrations. There is some concern about the effects on absorption of lipid-soluble vitamins and pro-vitamins, but safety tests lasting for up to 3 years found no serious adverse effects. Conclusions. The target market for this spread should be nonpregnant, non-lactating adults with hypercholesterolaemia and/or increased risk of IHD. If it is considered for use in hypercholesterolaemic children, fat-soluble vitamin status should be monitored. It is recommended that post-marketing surveillance should be established to determine long-term effects and safety

    Measurement of an excess in the yield of J/ψ\psi at very low pTp_{\rm T} in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    We report on the first measurement of an excess in the yield of J/ψ\psi at very low transverse momentum (pT<0.3p_{\rm T}< 0.3 GeV/cc) in peripheral hadronic Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV, performed by ALICE at the CERN LHC. Remarkably, the measured nuclear modification factor of J/ψ\psi in the rapidity range 2.5<y<42.5<y<4 reaches about 7 (2) in the pTp_{\rm T} range 0-0.3 GeV/cc in the 70-90% (50-70%) centrality class. The J/ψ\psi production cross section associated with the observed excess is obtained under the hypothesis that coherent photoproduction of J/ψ\psi is the underlying physics mechanism. If confirmed, the observation of J/ψ\psi coherent photoproduction in Pb-Pb collisions at impact parameters smaller than twice the nuclear radius opens new theoretical and experimental challenges and opportunities. In particular, coherent photoproduction accompanying hadronic collisions may provide insight into the dynamics of photoproduction and nuclear reactions, as well as become a novel probe of the Quark-Gluon Plasma.Comment: 18 pages, 3 captioned figures, 1 table, authors from page 13, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/191
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