1,171 research outputs found

    Combinations of bleeding and ischemic risk and their association with clinical outcomes in acute coronary syndrome.

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    Background: Clinical predictors of future ischemic events in patients with acute coronary syndrome (ACS) are also risk factors for bleeding, with patients often at high-risk of both outcomes. We aimed to define the clinical outcomes and provision of guideline-recommended care in ACS management for different combinations of ischemic and bleeding risk defined using a combined GRACE and CRUSADE score.Methods: A retrospective observational analysis of a national ACS database was performed for patients with ACS admitted to three tertiary centres from January 2010 to March 2016. Patients were stratified into 9 groups based on possible CRUSADE-GRACE risk combinations. Multiple logistic regression was used to estimate adjusted odds ratios (ORs [95% CI]) for outcomes (in-hospital net adverse cardiac events (NACE), in-hospital all-cause mortality, 30-day mortality and treatment strategy).Results: A total of 17,701 patients were included in the analysis. We observed a graded risk of mortality and adverse events in the high-risk GRACE strata (Groups 3, 6 and 9). Almost a third of patients with ACS were at a ‘dual high-risk’ (Group 9, 32%) and were independently associated with higher in-hospital NACE (composite of cardiac mortality, all-cause bleeding and re-infarction): aOR 6.33 [3.55, 11.29], all-cause mortality: aOR 14.17 [5.27, 38.1], all-cause bleeding: aOR 4.82 [1.96, 11.86], and 30-day mortality: aOR 10.79 [5.33, 21.81]. This group was also the least likely to be offered coronary angiography (aOR 0.24 [0.20, 0.29]) and dual anti-platelet therapy (aOR 0.26 [0.20, 0.34]). Conclusions: One in five patients presenting with an ACS are high ischemic and high bleeding risk, and these patients are more likely to experience poor clinical outcomes and reduced odds of receiving guideline-recommended therapy. <br/

    Size Dependence In The Disordered Kondo Problem

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    We study here the role randomly-placed non-magnetic scatterers play on the Kondo effect. We show that spin relaxation effects (with time τso\tau_s^o)in the vertex corrections to the Kondo self-energy lead to an exact cancellation of the singular temperature dependence arising from the diffusion poles. For a thin film of thickness LL and a mean-free path ℓ\ell, disorder provides a correction to the Kondo resistivity of the form τso/(kFLℓ2)ln⁥T\tau_s^o/(k_FL\ell^2)\ln T that explains both the disorder and sample-size depression of the Kondo effect observed by Blachly and Giordano (PRB {\bf 51}, 12537 (1995)).Comment: 11 pages, LaTeX, 2 Postscript figure

    Resistivity of a Metal between the Boltzmann Transport Regime and the Anderson Transition

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    We study the transport properties of a finite three dimensional disordered conductor, for both weak and strong scattering on impurities, employing the real-space Green function technique and related Landauer-type formula. The dirty metal is described by a nearest neighbor tight-binding Hamiltonian with a single s-orbital per site and random on-site potential (Anderson model). We compute exactly the zero-temperature conductance of a finite size sample placed between two semi-infinite disorder-free leads. The resistivity is found from the coefficient of linear scaling of the disorder averaged resistance with sample length. This ``quantum'' resistivity is compared to the semiclassical Boltzmann expression computed in both Born approximation and multiple scattering approximation.Comment: 5 pages, 3 embedded EPS figure

    Spin versus Lattice Polaron: Prediction for Electron-Doped CaMnO3

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    CaMnO3 is a simple bi-partite antiferromagnet(AF) which can be continuously electron-doped up to LaMnO3. Electrons enter the doubly degenerate E_g subshell with spins aligned to the S=3/2 core of Mn^4+ (T_2g^3)$. We take the Hubbard and Hund energies to be effectively infinite. Our model Hamiltonian has two E_g orbitals per Mn atom, nearest neighbor hopping, nearest neighbor exchange coupling of the S=3/2 cores, and electron-phonon coupling of Mn orbitals to adjacent oxygen atoms. We solve this model for light doping. Electrons are confined in local ferromagnetic (FM) regions (spin polarons) where there proceeds an interesting competition between spin polarization (spin polarons) which enlarges the polaron, and lattice polarization (Jahn-Teller polarons) which makes it smaller. A symmetric 7-atom ferromagnetic cluster (Mn_7^27+) is the stable result, with net spin S=2 relative to the undoped AF. The distorted oxygen positions around the electron are predicted. The model also predicts a critical doping x_c=0.045 where the polaronic insulator becomes unstable relative to a FM metal.Comment: 9 pages with 7 embedded postscript figures and 2 table

    Complete Pseudohole and Heavy-Pseudoparticle Operator Representation for the Hubbard Chain

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    We introduce the pseudohole and heavy-pseudoparticle operator algebra that generates all Hubbard-chain eigenstates from a single reference vacuum. In addition to the pseudoholes already introduced for the description of the low-energy physics, this involves the heavy pseudoparticles associated with Hamiltonian eigenstates whose energy spectrum has a gap relatively to the many-electron ground state. We introduce a generalized pseudoparticle perturbation theory which describes the relevant finite-energy ground state transitions. In the present basis these excitations refer to a small density of excited pseudoparticles. Our operator basis goes beyond the Bethe-ansatz solution and it is the suitable and correct starting point for the study of the finite-frequency properties, which are of great relevance for the understanding of the unusual spectral properties detected in low-dimensional novel materials.Comment: LaTeX, 32 pages, no Figures. To be published in Phys. Rev. B (15th of August 1997

    Different paths to the modern state in Europe: the interaction between domestic political economy and interstate competition

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    Theoretical work on state formation and capacity has focused mostly on early modern Europe and on the experience of western European states during this period. While a number of European states monopolized domestic tax collection and achieved gains in state capacity during the early modern era, for others revenues stagnated or even declined, and these variations motivated alternative hypotheses for determinants of fiscal and state capacity. In this study we test the basic hypotheses in the existing literature making use of the large date set we have compiled for all of the leading states across the continent. We find strong empirical support for two prevailing threads in the literature, arguing respectively that interstate wars and changes in economic structure towards an urbanized economy had positive fiscal impact. Regarding the main point of contention in the theoretical literature, whether it was representative or authoritarian political regimes that facilitated the gains in fiscal capacity, we do not find conclusive evidence that one performed better than the other. Instead, the empirical evidence we have gathered lends supports to the hypothesis that when under pressure of war, the fiscal performance of representative regimes was better in the more urbanized-commercial economies and the fiscal performance of authoritarian regimes was better in rural-agrarian economie

    Stochastic Theory of Relativistic Particles Moving in a Quantum Field: II. Scalar Abraham-Lorentz-Dirac-Langevin Equation, Radiation Reaction and Vacuum Fluctuations

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    We apply the open systems concept and the influence functional formalism introduced in Paper I to establish a stochastic theory of relativistic moving spinless particles in a quantum scalar field. The stochastic regime resting between the quantum and semi-classical captures the statistical mechanical attributes of the full theory. Applying the particle-centric world-line quantization formulation to the quantum field theory of scalar QED we derive a time-dependent (scalar) Abraham-Lorentz-Dirac (ALD) equation and show that it is the correct semiclassical limit for nonlinear particle-field systems without the need of making the dipole or non-relativistic approximations. Progressing to the stochastic regime, we derive multiparticle ALD-Langevin equations for nonlinearly coupled particle-field systems. With these equations we show how to address time-dependent dissipation/noise/renormalization in the semiclassical and stochastic limits of QED. We clarify the the relation of radiation reaction, quantum dissipation and vacuum fluctuations and the role that initial conditions may play in producing non-Lorentz invariant noise. We emphasize the fundamental role of decoherence in reaching the semiclassical limit, which also suggests the correct way to think about the issues of runaway solutions and preacceleration from the presence of third derivative terms in the ALD equation. We show that the semiclassical self-consistent solutions obtained in this way are ``paradox'' and pathology free both technically and conceptually. This self-consistent treatment serves as a new platform for investigations into problems related to relativistic moving charges.Comment: RevTex; 20 pages, 3 figures, Replaced version has corrected typos, slightly modified derivation, improved discussion including new section with comparisons to related work, and expanded reference
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