71,687 research outputs found
Management of diabetes from preconception to the postnatal period: summary of NICE guidance
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
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 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 . The slope 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
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 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
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 decays in the perturbative QCD approach
Within the framework of perturbative QCD approach, we study the charmless
two-body decays . 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 also happen in the decays , while do not happen in
the decays . Here the contributions from the annihilation diagrams
play an important role to explain the lager transverse polarizations in the
decays , while they are not sensitive to the polarizations in
decays . (c) Our predictions for the direct CP-asymmetries agree
well with the QCDF results within errors. The decays 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
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.
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 model
We show that the finite difference, , between quadratic and
logarithmic divergent integrals ,
as encountered in the linear model, is in fact regularization
independent.Comment: 9 pages, 2 figures, Latex, to appear in Mod. Phys. Lett.
Dalitz plot slope parameters for decays and two particle interference
We study the possible distortion of phase-space in the decays , 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 rule in these decays.Comment: 17 pages, LaTex2e, 6 figures, v2 authors' affiliation modified, to
appear in Mod. Phys. Lett.
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