10,535 research outputs found

    Permanencia y cambio. Comprensión de los determinantes en el proyecto de arquitectura por medio del análisis de la obra producida en el despacho: “Brasil Arquitetura”

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    En este trabajo se ha buscado reflexionar acerca del tema de la producción arquitectónica, respecto a lo que sea el pensar, el concebir y el ejecutar arquitectura. Para eso, como objeto de análisis se ha elegido el despacho paulistano Brasil Arquitetura. Ubicado en la ciudad de São Paulo desde el año de 1979 es dirigido actualmente por Marcelo ferraz y Francisco Fanucci

    Band Power Analysis of the EEG Frequency Spectrum: An Evaluation of Interictal Periods of the Migraine Phase Using an Eyes-open vs. Eyes-closed Resting State Paradigm

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    Migraine is a primary headache disorder characterized by abnormal cortical activity acrossmigraine phases. However, less is known about electroencephalographic activity present duringasymptomatic periods of the migraine cycle or during resting-state conditions. Given the theorythat these testing conditions may reflect more permanent cortical states, the present studyexamined the interacting role of resting-state conditions (eyes-open vs. eyes-closed) andheadache diagnosis (migraine vs. control) on absolute band power across the EEG frequencyspectrum. In-line with previous research, we hypothesized that interictal periods of the migrainephase would be characterized by a difference in alpha frequency and an increase in slow-waveactivity compared to controls. We further predicted that group-related effects would differdepending on resting-state conditions. In general, slow-wave activity was greater in migriane compared to controls, although a significant interaction effect was obtained regarding fast-wavebeta power. Broad spectrum cortical differences between migraine and healthy controls arediscussed

    Translocation of NS3 from Hepatitis C Virus on RNA: Insights from Atomistic Molecular Simulations

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    Helicases are motor proteins that unwind double stranded nucleic acids and are important parts of the genetic apparatus. A notable member of this family of enzymes is the nun-structural protein NS3 from Hepatitis C Virus. NS3 helicase unwinds nucleic acids by translocating along a single strand. Single molecule experiments and X-ray crystallography suggest that NS3 follows an inchworm-like motion during the translocation mechanism, consuming one ATP molecule per cycle. In spite of the available experimental data, the mechanistic and chemical details of the translocation process are still unclear. The aim of this study is to model at atomistic detail the NS3h-RNA complex at the different stages of the translocation. For this purpose, atomistic molecular dynamics simulations were performed in explicit solvent in the presence and in the absence of ATP and ADP. Simulations were initialized based on existing crystallographic structures. All the stages of translocation were considered, and their relative stabilities were analyzed by computing electrostatic interactions, relative enthalpies, and hydrogen-bond patterns. Additionally, well-tempered metadynamics and Hamiltonian replica exchange simulations were performed to characterize the free-energy landscape associated to translocation and to describe the conformational transitions

    SWIPT techniques for multiuser MIMO broadcast systems

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    In this paper, we present an approach to solve the nonconvex optimization problem that arises when designing the transmit covariance matrices in multiuser multiple-input multiple-output (MIMO) broadcast networks implementing simultaneous wireless information and power transfer (SWIPT). The MIMO SWIPT design is formulated as a nonconvex optimization problem in which system sum rate is optimized considering per-user harvesting constraints. Two different approaches are proposed. The first approach is based on a classical gradient-based method for constrained optimization. The second approach is based on difference of convex (DC) programming. The idea behind this approach is to obtain a convex function that approximates the nonconvex objective and, then, solve a series of convex subproblems that, eventually, will provide a (locally) optimum solution of the general nonconvex problem. The solution obtained from the proposed approach is compared to the classical block-diagonalization (BD) strategy, typically used to solve the nonconvex multiuser MIMO network by forcing no inter-user interference. Simulation results show that the proposed approach improves both the system sum rate and the power harvested by users simultaneously. In terms of computational time, the proposed DC programming outperforms the classical gradient methods.Peer ReviewedPostprint (author's final draft

    Emerging role of angiogenesis in adaptive and maladaptive right ventricular remodeling in pulmonary hypertension

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    Right ventricular (RV) function is the primary prognostic factor for both morbidity and mortality in pulmonary hypertension (PH). RV hypertrophy is initially an adaptive physiological response to increased overload; however, with persistent and/or progressive afterload increase, this response frequently transitions to more pathological maladaptive remodeling. The mechanisms and disease processes underlying this transition are mostly unknown. Angiogenesis has recently emerged as a major modifier of RV adaptation in the setting of pressure overload. A novel paradigm has emerged that suggests that angiogenesis and angiogenic signaling are required for RV adaptation to afterload increases and that impaired and/or insufficient angiogenesis is a major driver of RV decompensation. Here, we summarize our current understanding of the concepts of maladaptive and adaptive RV remodeling, discuss the current literature on angiogenesis in the adapted and failing RV, and identify potential therapeutic approaches targeting angiogenesis in RV failure

    Towards a holistic understanding of the role of green infrastructure in improving urban air quality

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    Air pollution has been identified as a major problem in modern societies, threatening urban population health. Pedestrians, in particular, are directly exposed to one of the main sources of air pollutants: road transport, which is concentrated in proximity to the road, worsening the air. Green infrastructure (GI) has been promoted as a natural method for reducing exposure to local street air pollutants and providing additional Ecosystem Services with a range of environmental, social and economic benefits for citizens. The effectiveness of GI for improving air quality depends on the spatio-temporal context and the species-specific characteristics of the GI. Urban planting could maximise this benefit by a holistic understanding of the effects of GI in cities, balancing its benefits and constraints. However, little is currently known about the application of GI design and planning with regard to air pollution mitigation. Moreover, there is little agreement on the quantifiable effectiveness of GI in improving street air quality as its effectiveness is highly context dependent. Holistic guidance is therefore needed to inform practitioners of site- and species- specifics, trade-offs, and GI maintenance considerations for successful urban planting. This research reviews the academic literature addressing GI-related characteristics in streets, creating a holistic framework to help guide decision-makers on using GI solutions to improve air quality. Additionally, this research aims to understand how and which GI, along with other local characteristics, influence pedestrian air quality and how these characteristics are considered in real-world practice within the United Kingdom. This research progresses through three stages: First, the mechanisms by which GI is considered to influence air quality were identified through literature reviews. A specific literature review was then conducted for each mechanism to extract the associated GI and spatial characteristics that affect the potential for GI to mitigate urban air pollution. In the second stage, this list of characteristics, together with other Ecosystem Services, was discussed in consultation with practitioners in the UK. A survey was conducted to explore and evaluate the recommendations and resources available for planning plantings, as well as the practitioners’ knowledge about the characteristics associated with mitigating air pollution. Supported by results from the survey and the literature reviews, the third stage evaluated (validated) an easy-to-use computational model for its potential use in improving planting decisions for air pollution mitigation. Green infrastructure influences air quality by providing surfaces for pollutant deposition and absorption, effects on airflow and dispersion, and biogenic emissions. The relationship between the specific GI and the spatio-temporal context also influences air quality. Street structure, weather variables, and the type, shape and size of GI influence the dispersion of pollutants, with micro-and macro-morphological traits additionally influencing particulate deposition and gas absorption. In addition, maintaining GI lessens air quality deterioration by controlling biogenic emissions. According to participants in the survey, aesthetics were the principal drivers of urban planting, followed by improving well-being and increasing biodiversity and air pollution mitigation as a lesser priority. Characteristics such as airflow manipulation, leaf surface traits, and biogenic emissions were the less important influences in planting decisions in the UK, despite the fact that these characteristics influence air quality. Perhaps, a lack of communication of current information and low confidence about which specific characteristics have a tangible effect on air quality reduces the incorporation of GI for air pollution mitigation purposes. Uncertainties exist about the quantification of pollutants removed by GI. Field campaigns and computational models still need improvement to address the effectiveness of GI in real-world environments adequately and also to understand whether GI can exert a significant effect on pollutant levels under real-world conditions. This research showed that a promising and easy-to-use model used to evaluate the effectiveness of trees in removing particles was not an acceptable model to study the effect of GI on streets. The validation results showed a poor agreement between wind tunnel data and the model results. More effort is needed to develop better modelling tools that can quantify the actual effect of GI on improving street air quality. This research contributes to the air pollution mitigation field, explicitly helping to inform decision-making for more health-promoting urban settings by optimising the expected benefits of GI through a holistic understanding of their impacts. Facilitating the communication of current evidence through a holistic guide that considers both the benefits and trade-offs of planting decisions for air quality improvement. Improving information on air pollution mitigation to feed the decision-making process might maximise the benefits of GI planting for air pollution mitigation in streets.Open Acces
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