17 research outputs found

    Poisson-Jacobi reduction of homogeneous tensors

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    The notion of homogeneous tensors is discussed. We show that there is a one-to-one correspondence between multivector fields on a manifold MM, homogeneous with respect to a vector field Δ\Delta on MM, and first-order polydifferential operators on a closed submanifold NN of codimension 1 such that Δ\Delta is transversal to NN. This correspondence relates the Schouten-Nijenhuis bracket of multivector fields on MM to the Schouten-Jacobi bracket of first-order polydifferential operators on NN and generalizes the Poissonization of Jacobi manifolds. Actually, it can be viewed as a super-Poissonization. This procedure of passing from a homogeneous multivector field to a first-order polydifferential operator can be also understood as a sort of reduction; in the standard case -- a half of a Poisson reduction. A dual version of the above correspondence yields in particular the correspondence between Δ\Delta-homogeneous symplectic structures on MM and contact structures on NN.Comment: 19 pages, minor corrections, final version to appear in J. Phys. A: Math. Ge

    The European Solar Telescope

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    The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design combines the knowledge and expertise gathered by the European solar physics community during the construction and operation of state-of-the-art solar telescopes operating in visible and near-infrared wavelengths: the Swedish 1m Solar Telescope, the German Vacuum Tower Telescope and GREGOR, the French Télescope Héliographique pour l’Étude du Magnétisme et des Instabilités Solaires, and the Dutch Open Telescope. With its 4.2 m primary mirror and an open configuration, EST will become the most powerful European ground-based facility to study the Sun in the coming decades in the visible and near-infrared bands. EST uses the most innovative technological advances: the first adaptive secondary mirror ever used in a solar telescope, a complex multi-conjugate adaptive optics with deformable mirrors that form part of the optical design in a natural way, a polarimetrically compensated telescope design that eliminates the complex temporal variation and wavelength dependence of the telescope Mueller matrix, and an instrument suite containing several (etalon-based) tunable imaging spectropolarimeters and several integral field unit spectropolarimeters. This publication summarises some fundamental science questions that can be addressed with the telescope, together with a complete description of its major subsystems

    Effect of angina in the week before myocardial infarction on long-term cardiovascular morbidity and mortality after hospital discharge

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    Journal ArticleThe occurrence of angina in the week preceding myocardial infarction is associated with a reduction in cardiovascular complications in the acute phase. However, little is known about it relationship with prognosis after hospitalization (e.g., cardiovascular death and the development of heart failure or ischemic cardiomyopathy). The study included 290 consecutive patients admitted for a first myocardial infarction: 107 (36.9%) had preceding angina while 183 did not. Those with a history of ischemic cardiomyopathy of more than 1 week or structural cardiopathy were excluded. There was no difference in baseline characteristics between the two groups. Moreover, there was no difference in the rates of cardiovascular complications after hospital discharge: cardiovascular death (7% vs. 12.6%; P=.3), heart failure (7.4% vs. 11.6%; P=.2), and myocardial ischemia, including myocardial infarction and unstable angina, requiring hospitalization (41.2% vs. 31.3%; P=.3). The occurrence of angina in the week before a first myocardial infarction did not influence cardiovascular complications after hospital discharge (odds ratio = 0.75 [0.51-1.11]; P=.15).YesLa angina preinfarto precoz (semana previa) se asocia a una reducción de las complicaciones cardiovasculares en la fase aguda del infarto, pero es escasa la información sobre su relación con el pronóstico tras la fase hospitalaria (muerte cardiovascular y desarrollo de insuficiencia cardiaca e isquemia miocárdica). Estudiamos a 290 pacientes consecutivos ingresados con un primer infarto, 107 con angina precoz (36,9%) y 183 sin ella. Se excluyó a los pacientes con antecedentes de cardiopatía isquémica de más de 1 semana o cardiopatía estructural de base. No se aprecian diferencias en las características basales de ambos grupos. No hay diferencias en las complicaciones cardiovasculares tras el alta hospitalaria (mortalidad cardiovascular, 7 frente a 12,6%; p = 0,3), insuficiencia cardiaca (7,4 frente a 11,6%; p = 0,2) o isquemia miocárdica (infarto o angina inestable, 41,2 frente a 31,3%; p = 0,3) que motiven ingreso hospitalario. La angina precoz no es un factor asociado a complicaciones cardiovasculares tras el alta hospitalaria (odds ratio = 0,75; intervalo de confianza del 95%, 0,51-1,11; p = 0,15)
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