4,102 research outputs found
Pulmonary congestion assessment in heart failure: traditional and new tools
Congestion related to cardiac pressure and/or volume overload plays a central role in the pathophysiology, presentation, and prognosis of heart failure (HF). Most HF exacerbations are related to a progressive rise in cardiac filling pressures that precipitate pulmonary congestion and symptomatic decompensation. Furthermore, persistent symptoms and signs of congestion at discharge or among outpatients are strong predictors of an adverse outcome. Pulmonary congestion is also one of the most important diagnostic and therapeutic targets in chronic heart failure. The aim of this review is to analyze the importance of clinical, instrumental, and biochemical evaluation of congestion in HF by describing old and new tools. Lung ultrasonography (LUS) is an emerging method to assess pulmonary congestion. Accordingly, we describe the additive prognostic role of chest ultrasound with respect to traditional clinical and X-ray assessment in acute and chronic HF setting
Measuring topology in a laser-coupled honeycomb lattice: From Chern insulators to topological semi-metals
Ultracold fermions trapped in a honeycomb optical lattice constitute a
versatile setup to experimentally realize the Haldane model [Phys. Rev. Lett.
61, 2015 (1988)]. In this system, a non-uniform synthetic magnetic flux can be
engineered through laser-induced methods, explicitly breaking time-reversal
symmetry. This potentially opens a bulk gap in the energy spectrum, which is
associated with a non-trivial topological order, i.e., a non-zero Chern number.
In this work, we consider the possibility of producing and identifying such a
robust Chern insulator in the laser-coupled honeycomb lattice. We explore a
large parameter space spanned by experimentally controllable parameters and
obtain a variety of phase diagrams, clearly identifying the accessible
topologically non-trivial regimes. We discuss the signatures of Chern
insulators in cold-atom systems, considering available detection methods. We
also highlight the existence of topological semi-metals in this system, which
are gapless phases characterized by non-zero winding numbers, not present in
Haldane's original model.Comment: 30 pages, 12 figures, 4 Appendice
Completeness and consistency of renormalisation group flows
We study different renormalisation group flows for scale dependent effective
actions, including exact and proper-time renormalisation group flows. These
flows have a simple one loop structure. They differ in their dependence on the
full field-dependent propagator, which is linear for exact flows. We
investigate the inherent approximations of flows with a non-linear dependence
on the propagator. We check explicitly that standard perturbation theory is not
reproduced. We explain the origin of the discrepancy by providing links to
exact flows both in closed expressions and in given approximations. We show
that proper-time flows are approximations to Callan-Symanzik flows. Within a
background field formalism, we provide a generalised proper-time flow, which is
exact. Implications of these findings are discussed.Comment: 33 pages, 15 figures, revtex, typos corrected, to be published in
Phys.Rev.
Determinação do teor de metilxantinas e análise da variabilidade genética de seis variedades populares de erva-mate.
Os objetivos deste estudo foram determinar os conteúdos de metilxantinas e cafeína em folhas maduras de seis “variedades” populares de erva-mate (Ilex paraguariensis St. Hil. Aquifoliaceae) e avaliar a distância genética entre estas diferentes “variedades” por meio de marcadores RAPD (Random Amplified Polimorphic DNA). A concentração de metilxantinas foi determinada por espectrofotometria UV e a de cafeína por cromatografia gasosa. Foram estudadas seis “variedades” de erva-mate: nativa, folha grande, folha brilhosa, talo-roxo e folha cobre (consideradas variedades botânicas Ilex paraguariensis var. paraguariensis) e a “variedade” peluda (considerada variedade botânica Ilex paraguariensis var. vestita). A “variedade” folha cobre apresentou o maior conteúdo de metilxantinas (1,65 g%) e de cafeína (1,29 g%). A “variedade” peluda mostrou o menor teor de metilxantinas (0,25 g%) e de cafeína (0,06 g%). A diferença entre a quantidade de metilxantinas e cafeína deve-se provavelmente ao conteúdo das outras metilxantinas presentes na erva-mate, como a teobromina e a teofilina. Estas diferenças não foram observadas através de marcadores RAPD. De acordo com as análises do polimorfismo gerado pelo marcador RAPD, foram formados dois grupos distintos, os quais mostraram 58% de similaridade entre eles, utilizando o coeficiente de Jaccard. Um dos grupos incluiu as “variedades” folha cobre, peluda e nativa e o outro as “variedades” folha grande, brilhosa e talo roxo.bitstream/item/16992/1/Boletim_de_pesquisa08.pd
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