1,096 research outputs found

    Robust computer-aided synthesis and optimization of linear multivariable control systems with varying plant dynamics via AUTOCON

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    AUTOCON is an automated computer-aided design tool for the synthesis and optimization of linear multivariable control systems based upon user-defined control parameter optimization. Violations in stability and performance requirements are computed from constraints on Single Input/Single Output (SISO) open- and closed-loop transfer function frequency responses, and from constraints on the singular-value frequency responses of Multiple Input/Multiple Output (MIMO) transfer functions, for all critical plant variations. Optimum nonlinear programming algorithms are used in the search for local constrained solutions in which violations in stability and performance are caused either to vanish or be minimized for a proper selection of the control parameters. Classical control system stability and performance design can, in this way, be combined with modern multivariable robustness methods to offer general frequency response loop-shaping via a computer-aided design tool. Complete Nichols, Nyquist, Bode, singular-value Bode magnitude and transient response plots are produced, including user-defined boundary responses. AUTOCON is used to synthesize and optimize the lateral/directional flight control system for a typical high-performance aircraft

    Do international institutions matter? Socialization and international bureaucrats

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    A key component of (neo-)functionalist and constructivist approaches to the study of international organizations concerns staff socialization. Existing analyses of how, or indeed whether, staff develop more pro-internationalist attitudes over time draw predominantly on cross-sectional data. Yet, such data cannot address (self-)selection issues or capture the inherently temporal nature of attitude change. This article proposes an innovative approach to the study of international socialization using an explicitly longitudinal design. Analysing two waves of a large-scale survey conducted within the European Commission in 2008 and 2014, it examines the beliefs and values of the same individuals over time and exploits exogenous organizational changes to identify causal effects. Furthermore, the article theorizes and assesses specified scope conditions affecting socialization processes. Showing that international institutions do, in fact, influence value acquisition by individual bureaucrats, our results contest the widely held view that international organizations are not a socializing environment. Our analysis also demonstrates that age at entry and gender significantly affect the intensity of such value change

    Concentration Dependence of Superconductivity and Order-Disorder Transition in the Hexagonal Rubidium Tungsten Bronze RbxWO3. Interfacial and bulk properties

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    We revisited the problem of the stability of the superconducting state in RbxWO3 and identified the main causes of the contradictory data previously published. We have shown that the ordering of the Rb vacancies in the nonstoichiometric compounds have a major detrimental effect on the superconducting temperature Tc.The order-disorder transition is first order only near x = 0.25, where it cannot be quenched effectively and Tc is reduced below 1K. We found that the high Tc's which were sometimes deduced from resistivity measurements, and attributed to compounds with .25 < x < .30, are to be ascribed to interfacial superconductivity which generates spectacular non-linear effects. We also clarified the effect of acid etching and set more precisely the low-rubidium-content boundary of the hexagonal phase.This work makes clear that Tc would increase continuously (from 2 K to 5.5 K) as we approach this boundary (x = 0.20), if no ordering would take place - as its is approximately the case in CsxWO3. This behaviour is reminiscent of the tetragonal tungsten bronze NaxWO3 and asks the same question : what mechanism is responsible for this large increase of Tc despite the considerable associated reduction of the electron density of state ? By reviewing the other available data on these bronzes we conclude that the theoretical models which are able to answer this question are probably those where the instability of the lattice plays a major role and, particularly, the model which call upon local structural excitations (LSE), associated with the missing alkali atoms.Comment: To be published in Physical Review

    Integrating High-Sensitivity Troponin T and Sacubitril/Valsartan Treatment in HFpEF

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    OBJECTIVES This study examined the relationship among high-sensitivity troponin-T (hs-TnT), outcomes, and treatment with sacubitril/valsartan in patients with heart failure (HF) and preserved ejection fraction (HFpEF). BACKGROUND hs-TnT is a marker of myocardial injury in HF. METHODS The PARAGON-HF trial randomized 4,796 patients with HFpEF to sacubitril/valsartan or valsartan. We compared the risk of the composite outcome of cardiovascular death (CVD) and total HF hospitalization (HHF) according to hs-TnT. We also assessed the effect of allocated treatment on hs-TnT. RESULTS hs-TnT was available in 1,141 patients (24%) at run-in (median value: 17 ng/L) and 1,260 (26%) at randomization, with 58.3% having hs-TnT >14 ng/L (upper limit of normal). During a median follow-up of 34 months, there were 393 outcome events (82 CVD, 311 HHF). Adjusting for demographics, comorbidities, left ventricular ejection fraction (LVEF), and N-terminal pro B-type natriuretic peptide (NT-proBNP), log-hs-TnT at randomization was an independent predictor of the composite outcome (HR: 1.38; 95% CI: 1.19-1.59; P 17 ng/L) appeared to have a greater benefit from sacubitril/valsartan treatment when accounting for other potential effect modifiers (P interaction = 0.07). CONCLUSIONS Higher baseline hs-TnT was associated with increased risk of CVD/HHF, whereas hs-TnT decrease at 16 weeks led to lower subsequent risk of CVD/HHF compared with those who had persistently elevated values. Sacubitril/valsartan significantly reduced hs-TnT compared with valsartan. hs-TnT may be helpful in identifying patients with HFpEF who are more likely to benefit from sacubitril/valsartan. (J Am Coll Cardiol HF 2021;9:627-635) (c) 2021 by the American College of Cardiology Foundation

    Angiotensin-Neprilysin Inhibition in Heart Failure with Preserved Ejection Fraction

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    Background The angiotensin receptor-neprilysin inhibitor sacubitril-valsartan led to a reduced risk of hospitalization for heart failure or death from cardiovascular causes among patients with heart failure and reduced ejection fraction. The effect of angiotensin receptor-neprilysin inhibition in patients with heart failure with preserved ejection fraction is unclear. Methods We randomly assigned 4822 patients with New York Heart Association (NYHA) class II to IV heart failure, ejection fraction of 45% or higher, elevated level of natriuretic peptides, and structural heart disease to receive sacubitril-valsartan (target dose, 97 mg of sacubitril with 103 mg of valsartan twice daily) or valsartan (target dose, 160 mg twice daily). The primary outcome was a composite of total hospitalizations for heart failure and death from cardiovascular causes. Primary outcome components, secondary outcomes (including NYHA class change, worsening renal function, and change in Kansas City Cardiomyopathy Questionnaire [KCCQ] clinical summary score [scale, 0 to 100, with higher scores indicating fewer symptoms and physical limitations]), and safety were also assessed. Results There were 894 primary events in 526 patients in the sacubitril-valsartan group and 1009 primary events in 557 patients in the valsartan group (rate ratio, 0.87; 95% confidence interval [CI], 0.75 to 1.01; P=0.06). The incidence of death from cardiovascular causes was 8.5% in the sacubitril-valsartan group and 8.9% in the valsartan group (hazard ratio, 0.95; 95% CI, 0.79 to 1.16); there were 690 and 797 total hospitalizations for heart failure, respectively (rate ratio, 0.85; 95% CI, 0.72 to 1.00). NYHA class improved in 15.0% of the patients in the sacubitril-valsartan group and in 12.6% of those in the valsartan group (odds ratio, 1.45; 95% CI, 1.13 to 1.86); renal function worsened in 1.4% and 2.7%, respectively (hazard ratio, 0.50; 95% CI, 0.33 to 0.77). The mean change in the KCCQ clinical summary score at 8 months was 1.0 point (95% CI, 0.0 to 2.1) higher in the sacubitril-valsartan group. Patients in the sacubitril-valsartan group had a higher incidence of hypotension and angioedema and a lower incidence of hyperkalemia. Among 12 prespecified subgroups, there was suggestion of heterogeneity with possible benefit with sacubitril-valsartan in patients with lower ejection fraction and in women. Conclusions Sacubitril-valsartan did not result in a significantly lower rate of total hospitalizations for heart failure and death from cardiovascular causes among patients with heart failure and an ejection fraction of 45% or higher. (Funded by Novartis; PARAGON-HF ClinicalTrials.gov number, NCT01920711.

    Theory of Coexistence of Superconductivity and Ferroelectricity : A Dynamical Symmetry Model

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    We propose and investigate a model for the coexistence of Superconductivity (SC) and Ferroelectricity (FE) based on the dynamical symmetries su(2)su(2) for the pseudo-spin SC sector, h(4)h(4) for the displaced oscillator FE sector, and su(2)h(4)su(2) \otimes h(4) for the composite system. We assume a minimal symmetry-allowed coupling, and simplify the hamiltonian using a double mean field approximation (DMFA). A variational coherent state (VCS) trial wave-function is used for the ground state: the energy, and the relevant order parameters for SC and FE are obtained. For positive sign of the SC-FE coupling coefficient, a non-zero value of either order parameter can suppress the other (FE polarization suppresses SC and vice versa). This gives some support to "Matthias' Conjecture" [1964], that SC and FE tend to be mutually exclusive. For such a Ferroelectric Superconductor we predict: a) the SC gap Δ\Delta (and TcT_c ) will increase with increasing applied pressure when pressure quenches FE as in many ferroelectrics, and b) the FE polarization will increase with increaesing magnetic field up to HcH_c . The last result is equivalent to the prediction of a new type of Magneto-Electric Effect in a coexistent SC-FE material. Some discussion will be given of the relation of these results to the cuprate superconductors.Comment: 46 page

    Jeux péritextuels : "Quel petit vélo à guidon chromé au fond de la cour?" de Georges Perec

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    Chez Perec, style, techniques narratives, règles génériques deviennent prétexte au ludique. Toutefois, se jouer des conventions littéraires suppose qu'elles sont familières au lecteur. Or, s'il sait reconnaître les conventions du récit fictif traditionnel, sait-il toujours identifier les entorses qui y sont faites? Il faut que les jeux proposés se présentent ouvertement. Dans Quel petit vélo , le jeu commence par la remise en cause des fonctions et des conventions du péritexte (défini par Genette comme les éléments « situés autour du texte mais dans l'espace du même volume ») et jette une nouvelle lumière sur les possibilités du livre en tant que production et objet de consommation.In Perec's writing, style, narrative techniques, generic rules are always conducing to the ludic purpose of the author. Yet, playing with literary conventions assumes familiarity with these on the part of the reader. Now, if he can recognize the conventions of traditional narrative fiction, does it follow that he will also identify the dislocations done to them? It is necessary that the games proposed by the text should be overtly presented. In Quel petit vélo the game begins by questioning the functioning and conventions of what Genette defines as the "peritext" (those elements "situated around the text but within the book") and sheds new light on the possibilities of the book as both production and article of consumption

    Global Differences in Heart Failure With Preserved Ejection Fraction The PARAGON-HF Trial

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    Background: Heart failure with preserved ejection fraction (HFpEF) is a global public health problem with important regional differences. We investigated these differences in the PARAGON-HF trial (Prospective Comparison of Angiotensin Receptor Neprilysin Inhibitor With Angiotensin Receptor Blocker Global Outcomes in HFpEF), the largest and most inclusive global HFpEF trial. Methods: We studied differences in clinical characteristics, outcomes, and treatment effects of sacubitril/valsartan in 4796 patients with HFpEF from the PARAGON-HF trial, grouped according to geographic region. Results: Regional differences in patient characteristics and comorbidities were observed: patients from Western Europe were oldest (mean 75 +/- 7 years) with the highest prevalence of atrial fibrillation/flutter (36%); Central/Eastern European patients were youngest (mean 71 +/- 8 years) with the highest prevalence of coronary artery disease (50%); North American patients had the highest prevalence of obesity (65%) and diabetes (49%); Latin American patients were younger (73 +/- 9 years) and had a high prevalence of obesity (53%); and Asia-Pacific patients had a high prevalence of diabetes (44%), despite a low prevalence of obesity (26%). Rates of the primary composite end point of total hospitalizations for HF and death from cardiovascular causes were lower in patients from Central Europe (9 per 100 patient-years) and highest in patients from North America (28 per 100 patient-years), which was primarily driven by a greater number of total hospitalizations for HF. The effect of treatment with sacubitril-valsartan was not modified by region (interaction P>0.05). Conclusions: Among patients with HFpEF recruited worldwide in PARAGON-HF, there were important regional differences in clinical characteristics and outcomes, which may have implications for the design of future clinical trials. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01920711
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