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Structural Analysis of Glaucoma Brain and its Association with Ocular Parameters
No full textPurpose: To evaluate structural brain abnormalities in glaucoma patients using 3-Tesla magnetic resonance imaging and assess their correlation with associated structural and functional ocular findings. Patients and Methods: This cross-sectional prospective study included 30 glaucoma patients and 18 healthy volunteers. All participants underwent standard automated perimetry, spectral-domain optical coherence tomography, and 3.0-Tesla magnetic resonance imaging. Results: There was a significant difference between the surface area of the occipital pole in the left hemisphere of glaucoma patients (mean: 1253.9±149.3 mm2) and that of control subjects (mean: 1341.9±129.8 mm2), P=0.043. There was also a significant difference between the surface area of the occipital pole in the right hemisphere of glaucoma patients (mean: 1910.5±309.4 mm2) and that of control subjects (mean: 2089.1±164.2 mm2), P=0.029. There was no significant difference between the lingual, calcarine, superior frontal, and inferior frontal gyri of glaucoma patients and those of the control subjects (P>0.05 for all comparisons). The surface area of the occipital pole in the left hemisphere was significantly correlated with perimetry mean deviation values, visual acuity, age, and retinal nerve fiber layer thickness (P=0.001, P<0.001, P=0.010, P=0.006, respectively). The surface area of the occipital pole in the right hemisphere was significantly correlated with perimetry mean deviation values, visual field indices, visual acuity, age, and retinal nerve fiber layer thickness (P<0.001, P=0.007, P<0.001, P=0.046, P<0.001, respectively). Conclusions: Glaucoma patients presented a decreased occipital pole surface area in both hemispheres that independently correlated with functional and structural ocular parameters. Copyright © 2020 Wolters Kluwer Health, Inc
Critical Hydrogen Coverage Effect on the Hydrogenation of Ethylene Catalyzed by δ-MoC(001): An Ab Initio Thermodynamic and Kinetic Study
No full textThe molecular mechanism of ethylene (C2H4) hydrogenation on a δ-MoC(001) surface has been studied by periodic density functional theory methods. Activation energy barriers and elementary reaction rates have been calculated as a function of the hydrogen surface coverage, θH, with relevant properties derived from ab initio thermodynamics and kinetic rate estimates. The hydrogen coverage has a very strong effect on the adsorption energy and the second hydrogenation step of ethylene. A relatively low energy barrier favors the dissociation of H2 on δ-MoC(001) leading to medium H coverages (>0.4 of a monolayer) where the energy barrier for the full hydrogenation of ethylene is already below the corresponding barriers seen on Pt(111) and Pd(111). At a high H coverage of ∼0.85 of a monolayer, the C2H4 adsorbs at 1 atm and 300 K over a system having as-formed CH3 moiety species, which critically favors the C2H4 second hydrogenation, typically a rate limiting step, by reducing its activation energy to a negligible value of 0.08 eV, significantly lower than the equivalent values of ∼0.5 eV reported for Pt(111) and Pd(111) catalyst surfaces. The ethane desorption rate is larger than the surface intermediate elementary reaction rates, pointing to its desorption upon formation, closing the catalytic cycle. The present results put δ-MoC under the spotlight as an economic and improved replacement catalyst for Pt and Pd, with significant improvements in enthalpy and activation energy barriers. Here, we provide a detailed study for the C2H4 hydrogenation reaction mechanism over a carbide showing characteristics or features not seen on metal catalysts. These can be exploited when dealing with technical or industrial applications. © 2020 American Chemical Society
What has happened to the principles of Universality, Solidarity and Efficiency of the General System of Social Security in Health of Colombia? [¿qué ha pasado con los principios de Universalidad, Solidaridad y Eficiencia del Sistema General de Seguridad Social en Salud de Colombia?]
No full textThe Constitution of Colombia in its article 48 establishes that the guiding principles of the right to Social Security are universality, solidarity and efÂficiency. In 1993 the current General System of Social Security in Health was created through law 100. What has happened to these principles during these 25 years? With a descriptive-analytical methodology it was concluded that we have achieved universality and solidarity, but we have an inefficient system. © 2020 Centro Universitario de Brasilia. All rights reserved
Effect of sediment management decision on a hydropower plant value [Incidencia de la decisión de manejo de sedimentos en el valor de una central hidroeléctrica]
No full textSedimentation reduces the useful life of reservoirs and the value of hydropower plants. The aim is to determine the effect of sediment management decisions on the value of a plant. First, management alternatives are ranked with the AHP technique according to the perception of six experts. Second, the plant is valued by cash flow (FCL) and RESCON 2 BETA (RES). Results shows three alternatives ranked: reforestation, agriculture and dam construction. The useful life of reservoir increases in 84% (reforestation), 40% (agriculture), and 76% (dam). The value of the plant increases in 21% (FCL) and 21.74% (RES) for reforestation, 11.59% (FCL) and 13.18% (RES) for agriculture, and 20.07% (FCL) and 19.93% (RES) for dam building. It is concluded that sediment management affects the value of the plant since the useful life of the reservoir affects the value of continuity. © The author; licensee Universidad Nacional de Colombia
The influence of shape and orientation of scatters on the photonic band gap in two-dimensional Bravais-Moiré lattices
No full textWe perform a theoretical study of light propagation properties in two-dimensional square photonic crystals following Bravais-Moiré patterns, paying particular attention to the influence of the transversal shape and the orientation of the dielectric scatters onto the width and position of photonic band gaps. In this sense, we have considered both square and triangular transversal geometries for the dielectric scatters, together with the possible rotation of either all the elements or of one half of them, within the unit cell. Results for the photonic dispersion relations and band gaps are compared with those arising from the analysis of structures with simple bi-atomic Bravais unit cells. It comes out that wider photonic gaps appear when using square-shaped scatters. The use of Bravais-Moiré cells with the same kind of cores enhance the width of these gaps but shift them towards higher frequencies. Rotation of all elements within the cell in angles of 0.23 rad and 0.46 rad causes very small, if not null, changes in the photonic gap widths. However, the rotation of one half of the scatters in the cell, leaving the other half unrotated does produce noticeable modifications in the photonic band structure: For crystals made of square-shaped dielectric cores and simple cubic cells, this rotation strongly modifies the photonic structure, whilst for Bravais-Moiré crystals the same kind of change takes place for cells made of triangular-shaped cores. © 2020 Elsevier B.V
Scientific literature analysis on sustainability with the implication of open innovation
No full textStudies related to sustainability have been performed extensively around the world to evaluate the environmental, economic, and social impact of practices that meet the current and future needs of society. Based on the Scopus database, this study presents a bibliometric analysis for the long, medium, and short term to represent the characteristics of publications related to sustainability, identify research trends and thematic areas with a promising future in research. The analysis covers the following topics: general statistical description, most addressed thematic areas in sustainability, the geographical distribution of sustainability publications, and most influential and cited journals, authors, and articles. The results show sustainability prevails in areas like Engineering, Energy, Environmental Science, and Business, Management, and Accounting, and the publication rate in this field has increased exponentially in the last 10 years. This study also shows that the most productive journals in sustainability research are Sustainability Switzerland and Journal of Cleaner Production, focusing on interdisciplinary and transdisciplinary topics. Likewise, the critical issues of sustainability research are related to sustainable development, humans, environmental sustainability, climate change, decision-making, and environmental impact. As sustainability with open innovation represents a topic with an increasing number of publications, future research can be oriented toward this topic. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
A discrete particle swarm optimization to solve the put-away routing problem in distribution centres
No full textPut-away operations typically consist of moving products from depots to allocated storage locations using either operators or Material Handling Equipment (MHE), accounting for important operative costs in warehouses and impacting operations efficiency. Therefore, this paper aims to formulate and solve a Put-away Routing Problem (PRP) in distribution centres (DCs). This PRP formulation represents a novel approach due to the consideration of a fleet of homogeneous Material Handling Equipment (MHE), heterogeneous products linked to a put-away list size, depot location and multi-parallel aisles in a distribution centre. It should be noted that the slotting problem, rather than the PRP, has usually been studied in the literature, whereas the PRP is addressed in this paper. The PRP is solved using a discrete particle swarm optimization (PSO) algorithm that is compared to tabu search approaches (Classical Tabu Search (CTS), Tabu Search (TS) 2-Opt) and an empirical rule. As a result, it was found that a discrete PSO generates the best solutions, as the time savings range from 2 to 13% relative to CTS and TS 2-Opt for different combinations of factor levels evaluated in the experimentation. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
Genesis of Atrial Fibrillation Under Different Diffuse Fibrosis Density Related with Atmospheric Pollution. In-Silico Study
No full textAtrial remodeling is a widely acknowledged process that accelerates the susceptibility to and progression of atrial fibrillation. An increasingly recognized structural component is atrial fibrosis. Recent studies have shown that air pollution increases the risk of heart arrhythmias, where the exposure to particulate matter (PM) contributes to the generation of myocardial fibrosis, increasing the cardiovascular risk. The density and patterns of fibrosis (interstitial, compact and diffuse) are relevant in abnormal conduction and vulnerability to cardiac arrhythmias. Taking into account that fibrosis has been widely reported as one of the consequences of PM exposure, in this work, we evaluated the effects of low and high diffuse fibrosis density on conduction velocity and arrhythmic propagation patterns. For this purpose, cellular models of atrial myocyte and fibroblast were implemented in a 3D model of the human atria. Low (6.25%) and high (25%) fibrosis densities were simulated in the left atrium and its effect on conduction velocity and fibrillatory dynamics was evaluated. Results showed a conduction velocity reduction of 71% associated with a high fibrosis density. At low fibrosis density, few reentries were observed. On the other hand, at high fibrosis density, irregular propagation patterns, characterized by multiple wavelets and rotors, were observed. Our results suggest that high diffuse fibrosis density is associated with a significant conduction velocity reduction and with chaotic propagation patterns during atrial fibrillation. © 2020, Springer Nature Switzerland AG
Comprenhensive reparation as a prevailing principle in the responsability of the state –a perspective based on the constitutional court and the Colombian council of state case-law- [La reparación integral como principio prevalente en la responsabilidad del estado –una visión a partir de la jurisprudencia de la corte constitucional y del consejo de estado Colombiano–]
No full textThis paper addresses comprehensive reparation as a fundamental right and guiding principle in civil and State liability so that it is taken into account in a prevalent manner when assessing material and immaterial damages suffered by people. Due to the need to weigh such principle, there are many discussions raised from a normative, doctrinal, and – even-jurisprudential point of view, not only in the domestic sphere but also in the international sphere. However, its evolution has been remarkable and, currently, judges must apply it based on grounds of protection of human rights and international humanitarian law. For this research, the development, the analysis, the content, and the scope of the reparation principle was studied in the various international human rights instruments. Afterward, the research focuses on the criteria used by the Constitutional Court and the Council of State from 1991 onwards; along with the relevant doctrine on this subject. Lastly, the paper argues that the comprehensive reparation principle has consolidated as a prevalent principle within Colombian case-law which faces interesting interaction with the block of constitutionality and conventionality in the search of true restorative and transformative justice. © 2020, Corporacion Universitaria Republicana. All rights reserved
Virtual platforms that recognize learning styles and allow the deployment of Problem Based Learning methodology -ABP [Plataformas virtuales que reconocen estilos de aprendizaje y permiten el despliegue de metodología Aprendizaje Basado en Problemas -ABPV]
No full textThis article shows the results of a research project developed by the University of Medellín, Kuepa company, Minciencias and the Government of Antioquia, which starts with the problem of designing virtual courses based on traditional pedagogical approaches, that they do not promote active learning and do not take into account student learning styles. For this, a project is developed in which new functionalities are added to a virtual learning platform to allow the detection of student learning styles, and the configuration of courses under ABP methodology (Problem Based Learning). To achieve this, artificial intelligence (AI) techniques are used. In the development of the article it is shown that the model used to determine learning styles was Kolb, this one was used as input to train a SOM (Self-Organizing Maps) neural network. In this way, the material and problems assignment are customized according to the student characteristics. This article shows the modules that make up the platform and the built-in neural network structure to provide intelligence to the system are shown. © 2020 AISTI