71,687 research outputs found

    Management of diabetes from preconception to the postnatal period: summary of NICE guidance

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    Diabetes in pregnancy is associated with risks to the woman (for example, higher rates of miscarriage, preeclampsia, and preterm labour) and to the developing fetus and baby (for example, higher rates of congenital malformations, macrosomia, birth injury, and perinatal mortality). This article summarises the most recent guidance from the National Institute for Health and Clinical Excellence (NICE) on how to manage diabetes and its complications from preconception to the postnatal period

    Sum rules for total hadronic widths of light mesons and rectilineal stitch of the masses on the complex plane

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    Mass formulae for light meson multiplets derived by means of exotic commutator technique are written for complex masses and considered as complex mass sum rules (CMSR). The real parts of the (CMSR) give the well known mass formulae for real masses (Gell-Mann--Okubo, Schwinger and Ideal Mixing ones) and the imaginary parts of CMSR give appropriate sum rules for the total hadronic widths - width sum rules (WSR). Most of the observed meson nonets satisfy the Schwinger mass formula (S nonets). The CMSR predict for S nonet that the points (m,Γ)(m,\Gamma{}) form the rectilinear stitch (RS) on the complex mass plane. For low-mass nonets WSR are strongly violated due to ``kinematical'' suppression of the particle decays, but the violation decreases as the mass icreases and disappears above 1.5GeV\sim 1.5 GeV. The slope ksk_s of the RS is not predicted, but the data show that it is negative for all S nonets and its numerical values are concentrated in the vicinity of the value -0.5. If ksk_s is known for a nonet, we can evaluate ``kinematical'' suppressions of its individual particles. The masses and the widths of the S nonet mesons submit to some rules of ordering which matter in understanding the properties of the nonet. We give the table of the S nonets indicating masses, widths, mass and width orderings. We show also mass-width diagrams for them. We suggest to recognize a few multiplets as degenerate octets. In Appendix we analyze the nonets of 1+1^+ mesons.Comment: 20 pages, 3 figures; title and discussion expanded; additional text; final version accepted for publication in EPJ

    Decays of b hadrons and a possible new four-quark interaction

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    A possibility is considered of explaining the low experimental value of the ratio of the lifetimes tau(Lambda_b)/tau(B_d) by a new `centiweak' four-quark interaction, i.e with a strength on the order of 10^{-2}G_F. It is noted that the considered interaction can also improve agreement with the data on low semileptonic branching ratio B_{sl}(B) in B meson decays with a simultaneous slight decrease in the prediction for the average charm yield in those decays. The proposed new interaction modifies within the present experimental limits the predictions for differences of lifetimes among B mesons, and can thus be probed by more precise data on these differences. A sample model is briefly discussed, where the new interaction arises through a weak SU(2) singlet scalar field with quantum numbers of a diquark.Comment: 10 page

    Analysis of Ba1(1260)(b1(1235))KB \to a_1(1260)(b_1(1235))K^* decays in the perturbative QCD approach

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    Within the framework of perturbative QCD approach, we study the charmless two-body decays Ba1(1260)K,b1(1235)KB\to a_1(1260)K^*, b_1(1235)K^*. Using the decays constants and the light-cone distribution amplitudes for these mesons derived from the QCD sum rule method, we find the following results: (a) Our predictions for the branching ratios are consistent well with the QCDF results within errors, but much larger than the naive factorization approach calculation values. (b) We predict that the anomalous polarizations occurring in the decays BϕK,ρKB\to \phi K^*, \rho K^* also happen in the decays Ba1KB\to a_1K^*, while do not happen in the decays Bb1KB\to b_1K^*. Here the contributions from the annihilation diagrams play an important role to explain the lager transverse polarizations in the decays Ba1KB\to a_1K^*, while they are not sensitive to the polarizations in decays Bb1KB\to b_1K^*. (c) Our predictions for the direct CP-asymmetries agree well with the QCDF results within errors. The decays Bˉ0b1+K,Bb10K\bar B^0\to b^{+}_1K^{*-}, B^-\to b^{0}_1K^{*-} have larger direct CP-asymmetries, which could be measured by the present LHCb experiments.Comment: 12pages, 1figures. arXiv admin note: substantial text overlap with arXiv:1203.5913, arXiv:1203.591

    On the Parity Degeneracy of Baryons

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    The gross features of the observed baryon excitation spectrum below 2 GeV are well explained if the spectrum generating algebra of its intrinsic orbital angular momentum states is o(4)*su(2)_I. The spins of the resonances are obtained through the coupling of a Lorentz bi-spinor (1/2,0)+ (0,1/ 2) to a multiplet of the type (j,j) in its O(4)/O(3) reduction. The parities of the resonances follow from those of the O(3) members of the (j,j) multiplets. In this way relativistic SL(2,C) representations are constructed. For example, the first S11, P11, and D13 states with masses around 1500 MeV fit into the (1/2, 1/2)* [(1/2,0)+(0,1/2)] representation. The observed parities of the resonances correspond to natural parities of the (1/2,1/2) states. The second P11, S11, D13- together with the first P13, F15, D15, and (a predicted) F17 -resonances, centered around 1700 MeV, are organized into the (3/2,3/2)*[(1/2,0)+(0,1/2)] representation. I argue that the members of the (3/2,3/2) multiplet carry unnatural parities and that in this region chiral symmetry is restored. In the N(939)- N(1650) transition the chiral symmetry mode is changed, and therefore, a chiral phase transition is predicted to take place.Comment: 9 pages, LaTex, 1 figure; published in Mod.Phys.Lett. A12 (1997) 2373; minor misprints corrected, no statement change

    Development and validation of a risk score for chronic kidney disease in HIV infection using prospective cohort data from the D:A:D study.

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    Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice

    Regularizing the quark-level σ\sigma model

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    We show that the finite difference, iπ2m2-i\pi^2 m^2, between quadratic and logarithmic divergent integrals d4p[m2(p2m2)2(p2m2)1]\int d^4p[m^2(p^2-m^2)^{-2}-(p^2-m^2)^{-1}], as encountered in the linear σ\sigma model, is in fact regularization independent.Comment: 9 pages, 2 figures, Latex, to appear in Mod. Phys. Lett.

    Dalitz plot slope parameters for KπππK \to \pi\pi\pi decays and two particle interference

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    We study the possible distortion of phase-space in the decays KπππK \to \pi \pi \pi, which may result from final state interference among the decay products. Such distortion may influence the values of slope parameters extracted from the Dalitz plot distribution of these decays. We comment on the consequences on the magnitude of violation of the ΔI=1/2\mid \Delta I \mid = 1/2 rule in these decays.Comment: 17 pages, LaTex2e, 6 figures, v2 authors' affiliation modified, to appear in Mod. Phys. Lett.
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