1,231 research outputs found

    Instruments for the identification of patients in need of palliative care: protocol for a systematic review of measurement properties.

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    The objective of this review is to provide a comprehensive overview of the psychometric properties of available clinician-reported instruments developed to identify patients in need of general and specialized palliative care in acute care settings. Identification of patients in need of palliative care has been recognized as an area where many health care professionals need guidance. Differentiating between patients who require general palliative care and patients with more complex conditions who need specialized palliative care is particularly challenging. To our knowledge, no dedicated instruments are available to date to assist health care professionals to make this identification. Included studies will report on i) instruments aiming to identify patients in need of palliative care, ii) adult patients in need of palliative care in acute-care settings, iii) clinician-reported outcome measures, or iv) the development process or one or more of its measurement properties. Studies conducted in intensive care units, emergency departments, or nursing homes will be excluded. We will search for studies published in English and French in a variety of sources, including Embase, Medline Ovid SP, PubMed, CINAHL EBSCO, Google Scholar, government websites, and hospice websites. All citations will be screened and selected by two independent reviewers. Data extraction, quality assessment, and syntheses of included studies will be performed according to the COnsensus-based Standards for the selection of health Measurement Instruments (COSMIN) criteria. PROSPERO CRD42020150074

    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

    Strong Interactions at Low Energy

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    The lectures review some of the basic concepts relevant for an understanding of the low energy properties of the strong interactions: chiral symmetry, spontaneous symmetry breakdown, Goldstone bosons, quark condensate. The effective field theory used to analyze the low energy structure is briefly sketched. As an illustration, I discuss the implications of the recent data on the decay KππeνK\to \pi\pi e\nu for the magnitude of the quark condensate.Comment: Lectures given at the school of physics "Understanding the structure of hadrons", Prague, July 2001, 20 p

    A global fit of ππ\pi\pi and πK\pi K elastic scattering in ChPT with dispersion relations

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    We apply the one-loop results of the SU(3)L×SU(3)RSU(3)_L\times SU(3)_R ChPT suplemented with the inverse amplitude method to fit the available experimental data on ππ\pi\pi and πK\pi K scattering. With esentially only three parameters we describe accurately data corresponding to six different channels, namely (I,J)=(0,0),(2,0),(1,1),(1/2,0),(3/2,0)(I,J)=(0,0), (2,0), (1,1), (1/2,0), (3/2,0) and (1/2,1)(1/2,1). In addition we reproduce the first resonances of the (1,1)(1,1) and (1/2,1)(1/2,1) channel with the right mass corresponding to the ρ\rho and the K(892)K^*(892) particles.Comment: 19 pages, 5 figures available on request, FT/UCM/10/9

    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

    \pi\pi, K\pi and \pi N potential scattering and a prediction of a narrow \sigma meson resonance

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    Low energy scattering and bound state properties of the \pi N, \pi\pi and K\pi systems are studied as coupled channel problems using inversion potentials of phase shift data. In a first step we apply the potential model to explain recent measurements of pionic hydrogen shift and width. Secondly, predictions of the model for pionium lifetime and shift confirm a well known and widely used effective range expression. Thirdly, as extension of this confirmation, we predict an unexpected medium effect of the pionium lifetime which shortens by several orders of magnitude. The \sigma meson shows a narrow resonance structure as a function of the medium modified mass with the implication of being essentially energy independent. Similarly, we see this medium resonance effect realized for the K\pi system. To support our findings we present also results for the \rho meson and the \Delta(1232) resonance.Comment: 42 pages, 17 PS figures, REFTeX, epsfig.sty needed, submitted to Phys. Re

    Nonselective versus selective inhibition of inducible nitric oxide synthase in experimental endotoxic shock

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    The effects of two nitric oxide synthase (NOS) inhibitors with different isoform selectivity were compared in a murine model of endotoxemia. Mice challenged with 70 mg/kg intraperitoneal (ip) lipopolysaccharide (LPS) were treated 6 h after LPS with either NG-gamma-L-arginine methyl ester (L-NAME, nonselective NOS inhibitor, 10-60 mg/kg), L-canavanine (selective inhibitor of inducible NOS, 50-300 mg/kg), or saline (0.2 mL) given ip. In a subset of mice, plasma concentrations of nitrate (NO breakdown product), lipase (pancreas injury), lactate dehydrogenase, and transaminases (liver injury) were measured 16 h after LPS. Although both inhibitors reduced plasma nitrate, they produced contrasting effects on survival and organ injury. L-NAME enhanced liver damage and tended to accelerate the time of death, while L-canavanine significantly reduced mortality and had no deleterious effects in terms of organ damage. These results indicate that nonselective NOS inhibitors are detrimental in endotoxic shock and support the potential usefulness of selective inducible NOS inhibitors in this setting

    Pion Mass Effects in the Large NN Limit of \chiPT

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    We compute the large NN effective action of the O(N+1)/O(N)O(N+1)/O(N) non-linear sigma model including the effect of the pion mass to order mπ2/fπ2m^2_{\pi}/f_{\pi}^2. This action is more complex than the one corresponding to the chiral limit not only because of the pion propagators but also because chiral symmetry produce new interactions proportional to mπ2/fπ2m^2_{\pi}/f_{\pi}^2. We renormalize the action by including the appropriate counter terms and find the renormalization group equations for the corresponding couplings. Then we estudy the unitarity propierties of the scattering amplitudes. Finally our results are applied to the particular case of the linear sigma model and also are used to fit the pion scattering phase shifts.Comment: FT/UCM/18/9

    The Inverse Amplitude Method in ππ\pi\pi Scattering in Chiral Perturbation Theory to Two Loops

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    The inverse amplitude method is used to unitarize the two loop ππ\pi\pi scattering amplitudes of SU(2) Chiral Perturbation Theory in the I=0,J=0I=0,J=0, I=1,J=1I=1,J=1 and I=2,J=0I=2,J=0 channels. An error analysis in terms of the low energy one-loop parameters lˉ1,2,3,4,\bar l_{1,2,3,4,} and existing experimental data is undertaken. A comparison to standard resonance saturation values for the two loop coefficients bˉ1,2,3,4,5,6\bar b_{1,2,3,4,5,6} is also carried out. Crossing violations are quantified and the convergence of the expansion is discussed.Comment: (Latex, epsfig) 30 pages, 13 figures, 8 table

    Analyticity, Crossing Symmetry and the Limits of Chiral Perturbation Theory

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    The chiral Lagrangian for Goldstone boson scattering is a power series expansion in numbers of derivatives. Each successive term is suppressed by powers of a scale, Λχ\Lambda_\chi, which must be less than of order 4πf/N4\pi f/\sqrt{N} where ff is the Goldstone boson decay constant and NN is the number of flavors. The chiral expansion therefore breaks down at or below 4πf/N4 \pi f/\sqrt{N}. We argue that the breakdown of the chiral expansion is associated with the appearance of physical states other than Goldstone bosons. Because of crossing symmetry, some ``isospin'' channels will deviate from their low energy behavior well before they approach the scale at which their low energy amplitudes would violate unitarity. We argue that the estimates of ``oblique'' corrections from technicolor obtained by scaling from QCD are untrustworthy.Comment: harvmac, 18 pages (3 figures), HUTP-92/A025, BUHEP-92-18, new version fixes a TeX problem in little mod
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