4,057 research outputs found

    Electrical impedance as a technique for civil engineer structures surveillance : considerations on the galvanic insulation of samples

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    Since Electric Impedance Spectroscopy (EIS) has been widely used to determine physical properties of materials, it becomes necessary to evaluate different error contributions. In this work, it is studied the effect of the current leakage due to the lack of galvanic insulation from sample to ground, which could distort the results. In order to known the effects of ground coupling, an electric equivalent model is developed to distinguish between the contribution of the sample impedance and the stray impedance one. Model values agree with measured ones.Peer Reviewe

    Skeletal Muscle Mitochondrial Function/Dysfunction and Type 2 Diabetes

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    “Let food be your medicine and medicine be your food” stated Hippocrates, the father of Western medicine, in 400 B.C. This statement was based on the belief that food was able to influence disease, a concept that was revived several times in later years by painters, writers, scientists, and philosophers. One such philosopher, Ludwig Feuerbach, famously wrote in his 1863-4 essay “man is what he eats” introducing the idea that if we want to improve the spiritual conditions of people we must first improve their material conditions (Feuerbach, 2003). However, for years his warnings remained unheeded, at least in Western countries, in contrast to the teachings of Indian and Chinese medicine which for millennia have argued that a living organism has to assume a healthy diet. Like diet, physical activity has been also considered an important starting point for people's health. Hippocrates wrote in his book Regimen "if we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health" (Hippocrates, 1955). Our knowledge about the links between diet, exercise, and disease has vastly increased since Hippocrates time. A healthy lifestyle based on diet and physical activity is now considered the keystone of disease prevention and the basis for a healthy aging. However, modern society has created conditions with virtually unrestricted access to food resources and reduced physical activity, resulting in a positive overall energy balance. This is far from the environment of our ”hunter-gathered ancestros” whose genes were modulated over thousands of years adapting our metabolism to survive when food was scarce and maximizing energy storage when food became available. In terms of evolution, this radical and sudden lifestyle change in modern society has led to a dramatic increase in the incidence of metabolic diseases including obesity and type 2 diabetes mellitus (T2DM). It seems clear that the development of T2DM has a genetic component that becomes obvious when individuals are exposed to western lifestyle. However, environment plays a critical role in the incidence of the disease being obesity the main etiological cause of T2DM. Thus, modest weight loss is enough for obese glucose intolerant subjects to prevent the development of T2DM (National Task Force on the Prevention and Treatment of Obesity, 2000)..

    Hydrodynamic description for ballistic annihilation systems

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    The problem of the validity of a hydrodynamic description for a system in which there are no collisional invariants is addressed. Hydrodynamic equations have been derived and successfully tested against simulation data for a system where particles annihilate with a probability p, or collide elastically otherwise. The response of the system to a linear perturbation is analyzed as well

    Análisis de los metabolitos secundarios producidos por los agentes de control biológico Bacillus amyloliquefaciens CECT 8237 Y CECT 8238

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    Las cepas de Bacillus amyloliquefaciens CECT 8237 (UMAF6639) y CECT 8238 (UMAF6614) han sido ampliamente estudiadas en trabajos previos de nuestro grupo por su reseñable capacidad de biocontrol. Desde un principio ha destacado su actividad antagonista frente a Podosphaera fusca y ciertas bacterias patógenas de cucurbitáceas, siendo la antibiosis mediada por lipopéptidos tales como iturinas y fengicinas, uno de los principales mecanismos de acción. La secuenciación de los genomas de ambas cepas nos ha permitido localizar un amplio grupo de genes implicados en la síntesis de otros antibióticos ya descritos con anterioridad en otras cepas del género Bacillus. Sin embargo, las cepas CECT 8237 y CECT 8238 siguen mostrando mayor capacidad de biocontrol que otros agentes de biocontrol, lo que nos lleva a pensar en la producción de otras moléculas activas. Por ello, hemos desarrollado herramientas bioinformáticas que han facilitado la identificación de regiones poco conservadas con respecto al género Bacillus, así como regiones presentes solo en las cepas de estudio. También se pudo determinar si la adquisición de estas regiones genómicas por parte de estas bacterias se debía a procesos de transferencia horizontal, debido a las variaciones en el patrón de tripletes de aminoácidos y/o en el contenido en GC de dichas zonas. Actualmente, se está realizando la caracterización de algunas de las regiones identificadas en la cepa CECT 8237, cuyos genes parecen estar implicados en la síntesis de nuevos antibióticos no descritos hasta la fecha. Todos estos resultados refuerzan la hipótesis de que la producción de antibióticos es el mecanismo de acción determinante en la actividad de biocontrol de estas bacterias.Este trabajo ha sido financiado por ayudas del Plan Nacional de I+D+I del Ministerio de Ciencia e Innovación (AGL2010-21848-CO2-01) e Incentivos a Proyectos de Excelencia de la Junta de Andalucía (P10-AGR-5797), ambos cofinanciados con fondos FEDER (UE) y una ayuda del Plan Propio de Investigación de la Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech

    Assessment of fibre content and 3D profile in cylindrical SFRC specimens

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    The final publication is available at Springer via http://dx.doi.org/10.1617/s11527-014-0521-2The inductive method from Torrents et al. (Mater Struct 45(10):1577–1592, 2012, 1) is used to assess the fibre content and orientation in steel fibre reinforced concrete. Despite several advantages, the method presents limitations. On one hand, it was conceived for cubic specimens, which complicates its application in existing structures given the difficulty to obtain cubic cores. On the other hand, it only shows the fibre orientation in the three axes perpendicular to the faces of the specimen, being impossible to derive the orientation in other directions with these results. Moreover, it only gives average values without providing any information on the scatter or probabilistic distribution of the fibre orientation—a parameter that may be essential to for design and to explain differences in the behaviour of concretes apparently with the same average fibre distribution. The objective of this paper is to propose an assessment of the fibre content and orientation profile using the inductive method and cylindrical specimens. First, a modification of the method is proposed. Then, new equations are deducted to generalize the test to samples with different shapes and to assess the anisotropy level as well as the directions with the maximum and the minimum fibre contribution. An extensive experimental program and FEM simulations are performed to validate and determine the accuracy of the formulation developed. The results show that the execution of only one additional measurement per specimen is enough to determine the fibre probabilistic profile in all in-plane directions with a high accuracy.Peer ReviewedPostprint (author's final draft

    Detailed-level-accounting approach calculation of radiative properties of aluminium plasmas in a wide range of density and temperature

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    In this work it is accomplished a study of radiative properties of aluminium plasmas. It is analyzed the calculation of spectrally resolved and mean opacities both under NLTE and LTE approaches. Furthermore, the effect of the re-absorption of the radiation in these magnitudes is also examined. The calculations were performed into the detailed-levelaccounting approach including configuration interaction among the levels belonging to the same non-relativistic configuration

    Determination of level populations and radiative properties of optically thin and thick carbon plasmas

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    In several research fields of current interest such as astrophysics or inertial fusion confinement the knowledge of the interactions between the photons and the plasma particles, i.e. plasma radiative properties, result essential. Thus, for example, the understanding of these plasmas requires properties such as emissivities and opacities both for hydro-simulations and diagnostics. Carbon is one of the most interesting elements under investigation, since it is likely to be a major plasma-facing wall component in ITER, and it plays a major role in inertial fusion scenarios. Also, some laser experiments have focused on the spectrally resolved emission from hydrocarbon systems. Therefore, radiative properties from carbon plasmas must be known and, as a consequence, the theoretical study of these plasmas is a subject of current interest and many efforts are headed. In particular, recent NLTE workshops have focused on comparisons of modelling calculations for specific cases that allow testing the models since there are very few experimental measurements for carbon plasmas. For these reasons it is interesting to characterize them in a wide range of plasma conditions. In a previous work we carried out an exhaustive study of optically thin carbon plasmas under steady state condition in a wide range of electron densities and temperatures given by (1-200) eV and (10 12 -10 22 ) cm -3 respectively [1], where CE, NLTE or LTE regimes are achieved. In this work we analyse the reabsorption radiation effects for homogeneous carbon plasmas in planar geometry by means of the escape factor formalism. We focus our attention on the average ionization and ionic populations as well as the multifrequential and mean opacity. All the calculations presented in this work were performed by using ABAKO code [1] which integrates the RAPCAL code [2] in order to calculate optical properties for a wide range of temperatures and electron number densitie

    Influence of cardiovascular condition on retinal and retinal nerve fiber layer measurements

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    Objective To assess changes in the retinal nerve fiber layer (RNFL) and macula in subjects with cardiovascular risk factors or subclinical ischemia. Design Prospective and observational study. Methods A total of 152 healthy men underwent cardiovascular examination, including quantification of subclinical atheroma plaques by artery ultrasound scans, blood analysis, and a complete ophthalmic evaluation, including spectral-domain optical coherence tomography. The variables registered in cardiovascular examination were quantification of classic major risk factors, subclinical atheroma plaques by artery ultrasound scans, and analytical records. The ophthalmic evaluation registered RNFL and macular thickness. Results Mean subject age was 51.27±3.71 years. The 40 subjects without classic cardiovascular risk factors did not show differences in RNFL and macular thicknesses compared with the 112 subjects with at least one risk factor (except in sector 9 that showed higher thicknesses in subjects with 1 risk factor). Comparison between the group of subjects with and without atheroma plaques revealed no differences in RNFL and macular thicknesses. The sub-analysis of subjects with subclinical atheroma plaques in the common carotid artery revealed a significant reduction in central macular thickness in the left eye compared with the right eye (p = 0.016), RNFL in the superior quadrant (p = 0.007), and the 11 o’clock sector (p = 0.020). Comparison between smokers and nonsmokers revealed that smokers had significant thinning of the central macular thickness (p = 0.034), the nasal RNFL quadrant (p = 0.006), and the 3 and 5 o’clock sectors (p = 0.016 and 0.009). Conclusions Classic cardiovascular risk factors do not cause RNFL or macular thickness reduction, but tobacco smoking habit reduces nasal RNFL thickness. Subclinical atherosclerosis in the common carotid artery associates a reduction in central macular and nasal RNFL quadrant thicknesses in the left eye compared with the right eye

    Analytical opacity formulas for low Z plasmas

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    The accurate computation of radiative opacities is basic in the ICF target physics analysis, in which the radiation is an important feature to determine in detail. For this reason, accurate analytical formulas for giving mean opacities versus temperature and density of the plasma seem to be a useful tool. In this work we analyse some analytical expressions found in the literature for the opacity low Z plasmas in a wide range of temperature and densities. The validity of these formulas for computing the opacity under NLTE conditions is investigated using the new code ABAKO
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