1,249 research outputs found

    Impact of forgoing care because of costs on the quality of diabetes care: A three-year cohort study.

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    Forgoing care because of costs is a frequent situation in many countries, with estimated prevalences going from 4% to 30% [1–6]. It can be defined as a decision of not seeking care when needed because of financial reasons and the term is used interchangeably with unmet needs as both terms provide similar information [7]. Whereas most studies on the prevalence of forgoing care because of costs target the general populations, little is known of the prevalence of forgoing care for people with specific chronic conditions. The few studies exploring this issue reported a prevalence close to general population figures [5,8–9]. As people with chronic conditions have a high demand of health care, such prevalence may either be lower, since they are being followed by a health practitioner and are already navigating the system, or on the contrary, may be similar or higher, since they might decide to prioritize some health issues at the expense of other conditions. Our main objective was to assess the prevalence of forgoing care because of costs in Swiss patients with diabetes; a secondary objective was to explore whether forgoing care because of costs was related to a risk of worsening the quality of their care after three years of follow-up

    On CP-Odd Effects in K_L \to 2\pi and K^{\pm} \to \pi^{\pm} \pi^{\pm} \pi^{\mp} Decays Generated by Direct CP Violation

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    The amplitudes of the K^{\pm} \to 3\pi and K \to 2\pi decays are expressed in terms of different combinations of one and the same set of CP-conserving and CP-odd parameters. Extracting the magnitudes of these parameters from the data on K \to 2\pi decays, we estimate an expected CP-odd difference between the values of the slope parameters g^+ and g^- of the energy distributions of "odd" pions in K^+ \to \pi^+\pi^+\pi^- and K^- \to \pi^-\pi^-\pi^+ decays.Comment: 12 pages, no figure

    Heavy Ion Physics at the LHC with the ATLAS Detector

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    The ATLAS detector at CERN will provide a high-resolution longitudinally-segmented calorimeter and precision tracking for the upcoming study of heavy ion collisions at the LHC (sqrt(s_NN)=5520 GeV). The calorimeter covers |eta|<5 with both electromagnetic and hadronic sections, while the inner detector spectrometer covers |eta|<2.5. ATLAS will study a full range of observables necessary to characterize the hot and dense matter formed at the LHC. Global measurements (particle multiplicities, collective flow) will provide access into its thermodynamic and hydrodynamic properties. Measuring complete jets out to 100's of GeV will allow detailed studies of energy loss and its effect on jets. Quarkonia will provide a handle on deconfinement mechanisms. ATLAS will also study the structure of the nucleon and nucleus using forward physics probes and ultraperipheral collisions, both enabled by segmented Zero Degree Calorimeters.Comment: 9 pages, 8 figures, submitted to the Proceedings of Quark Matter 2006, Shanghai, China, November 14-20, 200

    Pion Interactions in Chiral Field Theories

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    We study in various chiral models the pion charge radius, πe3\pi_{e3} form factor ratio, πγγ\pi^\circ \to \gamma \gamma amplitude, charge pion polarizabilities, γγππ\gamma\gamma \to \pi^\circ \pi^\circ amplitude at low energies and the ππ\pi\pi s-wave I = 0 scattering length. We find that a quark-level linear sigma-model approach (also being consistent with tree-level vector meson dominance) is quite compatible with all of the above data.Comment: 12 pages, 9 eps figure

    The isospin symmetry breaking effects in Ke4K_{e4} decays

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    The Fermi-Watson theorem is generalized to the case of two coupled channels with different masses and applied to final state interaction in Ke4K_{e4} decays. The impact of considered effect on the phase of the ππ\pi\pi scattering is estimated and shown that it can be crucial for scattering lengths extraction from experimental data on Ke4K_{e4} decays

    Light quarks masses and condensates in QCD

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    We review some theoretical and phenomenological aspects of the scenario in which the spontaneous breaking of chiral symmetry is not triggered by a formation of a large condensate . Emphasis is put on the resulting pattern of light quark masses, on the constraints arising from QCD sum rules and on forthcoming experimental tests.Comment: 23 pages, 12 Postscript figures, LaTeX, uses svcon2e.sty, to be published in the Proceedings of the Workshop on Chiral Dynamics 1997, Mainz, Germany, Sept. 1-5, 199

    S-wave Meson-Meson Scattering from Unitarized U(3) Chiral Lagrangians

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    An investigation of the s-wave channels in meson-meson scattering is performed within a U(3) chiral unitary approach. Our calculations are based on a chiral effective Lagrangian which includes the eta' as an explicit degree of freedom and incorporates important features of the underlying QCD Lagrangian such as the axial U(1) anomaly. We employ a coupled channel Bethe-Salpeter equation to generate poles from composed states of two pseudoscalar mesons. Our results are compared with experimental phase shifts up to 1.5 GeV and effects of the eta' within this scheme are discussed.Comment: 18 pages, 6 figure

    Analysis of the nature of the ϕγπη\phi\to\gamma\pi\eta and ϕγπ0π0\phi\to\gamma\pi^0\pi^0 decays

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    We study interference patterns in the ϕ(γa0+π0ρ)γπη\phi\to(\gamma a_0+\pi^0\rho)\to\gamma\pi\eta and ϕ(γf0+π0ρ)γπ0π0\phi\to(\gamma f_0+\pi^0\rho)\to\gamma \pi^0\pi^0 reactions. Taking into account the interference, we fit the experimental data and show that the background reaction does not distort the π0η\pi^0\eta spectrum in the decay ϕγπη\phi\to\gamma\pi\eta everywhere over the energy region and does not distort the π0π0\pi^0\pi^0 spectrum in the decay ϕγπ0π0\phi\to\gamma\pi^0\pi^0 in the wide region of the π0π0\pi^0\pi^0 system invariant mass, mππ>670m_{\pi\pi}>670 MeV, or when the photon energy is less than 300 MeV. We discuss the details of the scalar meson production in the radiative decays and note that there are reasonable arguments in favor of the one-loop mechanism ϕK+Kγa0\phi\to K^+K^-\to\gamma a_0 and ϕK+Kγf0\phi\to K^+K^-\to\gamma f_0. We discuss also distinctions between the four-quark, molecular, and two-quark models and argue that the Novosibirsk data give evidence in favor of the four-quark nature of the scalar a0(980)a_0(980) and f0(980)f_0(980) mesons.Comment: 15 pages, 7 figures, title is changed, a few clarifying remarks are added, accepted for publication in Physical Review

    Bethe-Salpeter Approach for Unitarized Chiral Perturbation Theory

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    The Bethe-Salpeter equation restores exact elastic unitarity in the ss- channel by summing up an infinite set of chiral loops. We use this equation to show how a chiral expansion can be undertaken in the two particle irreducible amplitude and the propagators accomplishing exact elastic unitarity at any step. Renormalizability of the amplitudes can be achieved by allowing for an infinite set of counter-terms as it is the case in ordinary Chiral Perturbation Theory. Crossing constraints can be imposed on the parameters to a given order. Within this framework, we calculate the leading and next-to-leading contributions to the elastic ππ\pi \pi scattering amplitudes, for all isospin channels, and to the vector and scalar pion form factors in several renormalization schemes. A satisfactory description of amplitudes and form factors is obtained. In this latter case, Watson's theorem is automatically satisfied. From such studies we obtain a quite accurate determination of some of the ChPT SU(2)SU(2)-low energy parameters ({\bar l}_1 - {\bar l}_2 = -6.1\er{0.1}{0.3} and lˉ6=19.14±0.19{\bar l}_6= 19.14 \pm 0.19). We also compare the two loop piece of our amplitudes to recent two--loop calculations.Comment: 63 pages, 9 figures. Some discussions on off-shell ambiguities and convergence of the expansion adde

    UNDERSTANDING THE SCALAR MESON qqˉq\bar q NONET

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    It is shown that one can fit the available data on the a0(980), f0(980), f0(1300) and K*0(1430) mesons as a distorted 0++ qq bar nonet using very few (5-6) parameters and an improved version of the unitarized quark model. This includes all light two-pseudoscalar thresholds, constraints from Adler zeroes, flavour symmetric couplings, unitarity and physically acceptable analyticity. The parameters include a bare uu bar or dd bar mass, an over-all coupling constant, a cutoff and a strange quark mass of 100 MeV, which is in accord with expectations from the quark model. It is found that in particular for the a0(980) and f0(980) the KK bar component in the wave function is large, i.e., for a large fraction of the time the qq bar state is transformed into a virtual KK bar pair. This KK bar component, together with a similar component of eta' pi for the a0(980) , and eta eta, eta eta' and eta' eta' components for the f0(980), causes the substantial shift to a lower mass than what is naively expected from the qq bar component alone. Mass, width and mixing parameters, including sheet and pole positions, of the four resonances are given, with a detailed pedagogical discussion of their meaning.Comment: 35 pages in plain latex (ZPC in press), 10 figures obtainable from the author ([email protected]) with regular mail or as a large PS fil
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