Time-frequency analysis of signals using support adaptive Hermite-Gaussian expansions

Cataloged from PDF version of article.Since Hermite–Gaussian (HG) functions provide an orthonormal basis with the most compact time– frequency supports (TFSs), they are ideally suited for time–frequency component analysis of finite energy signals. For a signal component whose TFS tightly fits into a circular region around the origin, HG function expansion provides optimal representation by using the fewest number of basis functions. However, for signal components whose TFS has a non-circular shape away from the origin, straight forward expansions require excessively large number of HGs resulting to noise fitting. Furthermore, for closely spaced signal components with non-circular TFSs, direct application of HG expansion cannot provide reliable estimates to the individual signal components. To alleviate these problems, by using expectation maximization (EM) iterations, we propose a fully automated pre-processing technique which identifies and transforms TFSs of individual signal components to circular regions centered around the origin so that reliable signal estimates for the signal components can be obtained. The HG expansion order for each signal component is determined by using a robust estimation technique. Then, the estimated components are post-processed to transform their TFSs back to their original positions. The proposed technique can be used to analyze signals with overlapping components as long as the overlapped supports of the components have an area smaller than the effective support of a Gaussian atom which has the smallest time-bandwidth product. It is shown that if the area of the overlap region is larger than this threshold, the components cannot be uniquely identified. Obtained results on the synthetic and real signals demonstrate the effectiveness for the proposed time–frequency analysis technique under severe noise cases. © 2012 Elsevier Inc. All rights reserved

Interleukin-1 regulates multiple atherogenic mechanisms in response to fat feeding

Background: Atherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood pressure and promote atheroma. Methodology/Principal Findings: Apoe(-/-) and Apoe(-/-)/IL-1R1(-/-) mice were fed high fat diets for 8 weeks, and their blood pressure and atherosclerosis development measured. Apoe(-/-)/IL-R1(-/-) mice had a reduced blood pressure and significantly less atheroma than Apoe(-/-) mice. Selective loss of IL-1 signaling in the vessel wall by bone marrow transplantation also reduced plaque burden (p<0.05). This was associated with an IL-1 mediated loss of endothelium-dependent relaxation and an increase in vessel wall Nox 4. Inhibition of IL-1 restored endothelium-dependent vasodilatation and reduced levels of arterial oxidative stress. Conclusions/Significance: The IL-1 cytokine system links atherogenic environmental stimuli with arterial inflammation, oxidative stress, increased blood pressure and atherosclerosis. This is the first demonstration that inhibition of a single cytokine can block the rise in blood pressure in response to an environmental stimulus. IL-1 inhibition may have profound beneficial effects on atherogenesis in man

Nuclear Inelastic X-Ray Scattering of FeO to 48 GPa

The partial density of vibrational states has been measured for Fe in compressed FeO (w\"ustite) using nuclear resonant inelastic x-ray scattering. Substantial changes have been observed in the overall shape of the density of states close to the magnetic transiton around 20 GPa from the paramagnetic (low pressure) to the antiferromagnetic (high pressure) state. Our data indicate a substantial softening of the aggregate sound velocities far below the transition, starting between 5 and 10 GPa. This is consistent with recent radial x-ray diffraction measurements of the elastic constants in FeO. The results indicate that strong magnetoelastic coupling in FeO is the driving force behind the changes in the phonon spectrum of FeO.Comment: 4 pages, 4 figure

Measuring velocity of sound with nuclear resonant inelastic x-ray scattering

Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crystalline and noncrystalline materials. Advantages and limitations of this method are elucidated

Video enhancement using adaptive spatio-temporal connective filter and piecewise mapping

This paper presents a novel video enhancement system based on an adaptive spatio-temporal connective (ASTC) noise filter and an adaptive piecewise mapping function (APMF). For ill-exposed videos or those with much noise, we first introduce a novel local image statistic to identify impulse noise pixels, and then incorporate it into the classical bilateral filter to form ASTC, aiming to reduce the mixture of the most two common types of noises - Gaussian and impulse noises in spatial and temporal directions. After noise removal, we enhance the video contrast with APMF based on the statistical information of frame segmentation results. The experiment results demonstrate that, for diverse low-quality videos corrupted by mixed noise, underexposure, overexposure, or any mixture of the above, the proposed system can automatically produce satisfactory results

Strong cooperative coupling of pressure-induced magnetic order and nematicity in FeSe

A hallmark of the iron-based superconductors is the strong coupling between magnetic, structural and electronic degrees of freedom. However, a universal picture of the normal state properties of these compounds has been confounded by recent investigations of FeSe where the nematic (structural) and magnetic transitions appear to be decoupled. Here, using synchrotron-based high-energy x-ray diffraction and time-domain Mössbauer spectroscopy, we show that nematicity and magnetism in FeSe under applied pressure are indeed strongly coupled. Distinct structural and magnetic transitions are observed for pressures between 1.0 and 1.7 GPa and merge into a single first-order transition for pressures ≳1.7 GPa, reminiscent of what has been found for the evolution of these transitions in the prototypical system Ba(Fe1−xCox)2As2. Our results are consistent with a spin-driven mechanism for nematic order in FeSe and provide an important step towards a universal description of the normal state properties of the iron-based superconductors

Atrial fibrillation, anticoagulation management and risk of stroke in the Cardiomyopathy/Myocarditis registry of the EURObservational Research Programme of the European Society of Cardiology

Aims: Cardiomyopathies are a heterogeneous group of disorders that increase the risk for atrial fibrillation (AF). The aim of the study is to assess the prevalence of AF, anticoagulation management, and risk of stroke/transient ischaemic attack (TIA) in patients with cardiomyopathy. / Methods and results: Three thousand two hundred eight consecutive adult patients with cardiomyopathy (34.9% female; median age: 55.0 years) were prospectively enrolled as part of the EURObservational Research Programme Cardiomyopathy/Myocarditis Registry. At baseline, 903 (28.2%) patients had AF (29.4% dilated, 27.5% hypertrophic, 51.5% restrictive, and 14.7% arrhythmogenic right ventricular cardiomyopathy, P < 0.001). AF was associated with more advanced New York Heart Association class (P < 0.001), increased prevalence of cardiovascular risk factors and co‐morbidities, and a history of stroke/TIA (P < 0.001). Oral anticoagulation was administered in 71.7% of patients with AF (vitamin K antagonist: 51.6%; direct oral anticoagulant: 20.1%). At 1 year follow‐up, the incidence of cardiovascular endpoints was as follows: stroke/TIA 1.85% (AF vs. non‐AF: 3.17% vs. 1.19%, P < 0.001), death from any cause 3.43% (AF vs. non‐AF: 5.39% vs. 2.50%, P < 0.001), and death from heart failure 1.67% (AF vs. non‐AF: 2.44% vs. 1.31%, P = 0.033). The independent predictors for stroke/TIA were as follows: AF [odds ratio (OR) 2.812, P = 0.005], history of stroke (OR 7.311, P = 0.010), and anaemia (OR 3.119, P = 0.006). / Conclusions: The study reveals a high prevalence and diverse distribution of AF in patients with cardiomyopathies, inadequate anticoagulation regimen, and high risk of stroke/TIA in this population

Sobre a (im)prescritibilidade da pretensão de ressarcimento de danos causados ao erário por ato de improbidade administrativa

TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Jurídicas. Direito.O presente trabalho objetiva dirimir a dúvida existente acerca da sujeição da pretensão de ressarcimento de danos causados ao erário por ato de improbidade administrativa ao instituto da prescrição. Tal incerteza surge a partir da redação da ressalva contida no artigo 37, § 5º, da Constituição da República Federativa do Brasil, que possibilita variadas interpretações, algumas defendendo a imprescritibilidade de tal pretensão, outras advogando a tese da sujeição de tal pretensão a lapso prescricional. Com o fito de se concluir pelo entendimento mais condizente à ordem jurídico-normativa brasileira, divide-se o estudo em três capítulos principais. No primeiro, são delineados o conceito e a finalidade da prescrição, apresentando-se a garantia da segurança jurídica como sendo seu fundamento constitucional. Em seguida, são explanadas as noções de supremacia do interesse público e segurança jurídica, entendidas por boa parte dos estudiosos como os dois princípios a partir dos quais deve ser analisada a questão. Por fim, no terceiro e último capítulo, depois de serem descritas as principais interpretações que podem derivar da leitura do dispositivo, chega-se ao entendimento pela conformação da pretensão estudada ao manto prescricional. Esta acepção parece melhor se amoldar aos contornos pretendidos pelo ordenamento jurídico-constitucional contemporâneo para a construção de um Direito Administrativo efetivamente democrático, com a sobrevalorização dos direitos fundamentais, individuais e coletivos, e a realização da ideia de supremacia da Constituição. No plano legal e normativo, a compreensão pela prescritibilidade afigura-se coerente à própria construção histórica do comando constitucional, com a delimitação de dois regimes prescricionais distintos para as pretensões originadas com a prática de ato de improbidade. Da mesma forma, a identificação do ressarcimento como consequência, e não sanção, do ato ímprobo, bem como a evolução do tratamento dado à matéria pelo Supremo Tribunal Federal parecem caminhar no mesmo sentido interpretativo