119 research outputs found

    Influence of fly ash blending on hydration and physical behavior of Belite-Alite-Ye'elimite cements

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    A cement powder, composed of belite, alite and ye’elimite, was blended with 0, 15 and 30 wt% of fly ash and the resulting lended cements were further characterized. During hydration, the presence of fly ash caused the partial inhibition of both AFt degradation and belite reactivity, even after 180 days. The compressive strength of the corresponding mortars increased by increasing the fly ash content (68, 73 and 82 MPa for mortars with 0, 15 and 30 wt% of fly ash, respectively, at 180 curing days), mainly due to the diminishing porosity and pore size values. Although pozzolanic reaction has not been directly proved there are indirect evidences.This work is part of the Ph.D. of D. Londono-Zuluaga funded by Beca Colciencias 646—Doctorado en el exterior and Enlaza Mundos 2013 program grant. Cement and Building materials group (CEMATCO) from National University of Colombia is acknowledged for providing the calorimetric measurements. Funding from Spanish MINECO BIA2017-82391-R and I3 (IEDI-2016-0079) grants, co-funded by FEDER, are acknowledged

    Communication for Peaceful Social Change and Global Citizenry

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    The adoption of the 17 Sustainable Development Goals (SDGs) by the United Nations (UN) in 2015 represents a universal call to action involving multiple international actors for the purpose of eradicating poverty, improving living conditions and promoting peace. This entry provides a theoretical overview of the contributions of scholars and practitioners who highlight the importance of a transformative, educational and emancipatory communication by different social actors to establish the main lines of action for the 2030 Agenda for Sustainable Development. This communicative model involves the coordination of actors and strategies, both short- and long-term, cross-cutting actions and discourses to build social, cultural and political settings based on the criteria of peace, equality, social justice and human rights. Specifically, this entails a contribution to the objectives set out in SDG 16, “Peace, Justice and Strong Institutions”, given that the proposed theoretical framework is grounded in Communication for Peace and Communication for Social Change, and includes a systematization of different strategies and experiences from a variety of social issuers, mainly institutions, non-governmental organizations (NGOs) or social movements, aimed at promoting peaceful and inclusive societies. Specifically, communication for peaceful social change and global citizenry contributes to the achievement of specific SDG 16 objectives, particularly 16.1: Significantly reduce all forms of violence... [...

    Enthalpy of formation of ye’elimite and ternesite

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    Calcium sulfoaluminate clinkers containing ye’elimite (Ca4Al6O12(SO4)) and ternesite (Ca5(SiO4)2SO4) are being widely investigated as components of calcium sulfoaluminate cement clinkers. These may become low energy replacements for Portland cement. Conditional thermodynamic data for ye’elimite and ternesite (enthalpy of formation) have been determined experimentally using a combination of techniques: isothermal conduction calorimetry, X-ray powder diffraction and thermogravimetric analysis. The enthalpies of formation of ye’elimite and ternesite at 25 °C were determined to be − 8523 and − 5993 kJ mol−1, respectively

    Recent advances in organic synthesis using light-mediated n-heterocyclic carbene catalysis

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    The combination of photocatalysis with other ground state catalytic systems have attracted much attention recently due to the enormous synthetic potential offered by a dual activation mode. The use of N-heterocyclic carbene (NHC) as organocatalysts emerged as an important synthetic tool. Its ability to harness umpolung reactivity by the formation of the Breslow intermediate has been employed in the synthesis of thousands of biologically important compounds. However, the available coupling partners are relatively restricted, and its combination with other catalytic systems might improve its synthetic versatility. Thus, merging photoredox and N-heterocyclic carbene (NHC) catalysis has emerged recently as a powerful strategy to develop new transformations and give access to a whole new branch of synthetic possibilities. This review compiles the NHC catalyzed methods mediated by light, either in the presence or absence of an external photocatalyst, that have been described so far, and aims to give an accurate overview of the potential of this activation modeL.M. acknowledges the Autonomous Community of Madrid (CAM) for the financial support (PEJD-2019-PRE/AMB-16640 and SI1/PJI/ 2019-00237) and for an “Atracción de Talento Investigador” contract (2017-T2/AMB-5037

    2 nd Brazilian Consensus on Chagas Disease, 2015

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    Abstract Chagas disease is a neglected chronic condition with a high burden of morbidity and mortality. It has considerable psychological, social, and economic impacts. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on the articulation and strategic contribution of renowned Brazilian experts with knowledge and experience on various aspects of the disease. It is the result of a close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. It is hoped that this document will strengthen the development of integrated actions against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research

    Baixa percepção de risco entre adolescentes espanhóis em relação ao consumo de álcool

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    Según los estudios recientes, los adolescentes españoles muestran una baja percepción del riesgo asociado al consumo de alcohol. El objetivo de la presente investigación es analizar los factores que favorecen esta baja percepción a partir de la opinión de un grupo de 32 profesionales/expertos en adolescencia, familia, escuela, medios de comunicación y políticas locales. Se utilizó una metodología cualitativa, fundamentada en Grounded Theory, a partir de la información obtenida mediante 5 grupos de discusión guiados por entrevistas semiestructuradas. Se identificaron 12 factores o subcategorías agrupados en 4 categorías generales: riesgo a corto plazo, inmediatez y percepción de invulnerabilidad (categoría ¿pensamiento adolescente¿); concepción benévola del alcohol, normalización del consumo y binomio alcohol-diversión (categoría ¿normas sociales¿); consumo habitual en los padres, inconsistencia verbal-no verbal en el modelado parental, consumo sin riesgo en los medios, consumo con resultados positivos en los medios (categoría ¿modelos sociales¿); excesivo contenido sanitario, riesgo a largo plazo (categoría ¿discurso preventivo¿). Tras discutir los resultados en el contexto de la literatura científica actual, se realizan varias propuestas con el objetivo de aumentar la percepción del riesgo en los adolescentes: incidir con mayor fuerza en contenidos sobre los riesgos a corto plazo del alcohol; orientar las estrategias educativas dirigidas al adolescente, también hacia los agentes de socialización, especialmente los padres; incidir en políticas centradas en la sustancia y en reducir la oferta.According to recent studies, Spanish adolescents show low perception of risk in alcohol consumption. The current study aims to analyze the factors that favor this low perception based on the opinion of a group of 32 professional experts on adolescence, family, school, mass media, and local policies. A qualitative methodology was used, based on Grounded Theory, using information from 5 focus groups guided by semi-structured interviews. Twelve factors or subcategories were identified, grouped in 4 general categories: short-term risk, immediacy, and perception of invulnerability (¿adolescent thinking¿ category); benevolent view of alcohol, normalization of consumption, and alcohol-entertainment binomial (¿social norms¿ category); parents¿ habitual consumption, verbal/non-verbal inconsistency in parental model, risk-free consumption depicted in the mass media, consumption with positive results in the media (¿social models¿ category); and excessive health content, long-term risk (¿preventive discourse¿ category). After discussing the results in the context of the current scientific literature, the article offers various proposals for increasing risk perception in adolescents: stronger impact of contents on short-term risks of alcohol; educational strategies targeted to adolescents to include agents of socialization, especially parents; and policies centered on the substance and reduction of supply.De acordo com estudos recentes, os adolescentes espanhóis mostram baixa percepção de risco em relação ao consumo de álcool. O estudo tem como objetivo analisar os fatores associados com a baixa percepção de risco, com base nas opiniões de um grupo de 32 especialistas em adolescência, família, escola, mídia e políticas locais. Foi utilizada uma metodologia qualitativa, baseada na Teoria Fundamentada, usando informações de cinco grupos focais orientados por entrevistas semi-estruturadas. Foram identificados 12 fatores ou subcategorias, agrupados em quatro categorias gerais: risco no curto prazo, imediatismo e percepção de invulnerabilidade (categoria de ¿pensamento adolescente¿); visão benevolente em relação ao álcool, normalização do consumo e binômio álcool-entretenimento (categoria de ¿normas sociais¿); consumo habitual pelos pais, inconsistência na comunicação verbal versus não verbal no modelo representado pelos pais, consumo isento de risco retratado pela mídia, consumo com resultados positivos na mídia (categoria de ¿modelos sociais¿) e excesso de conteúdo relacionado à saúde, risco no longo prazo (categoria de ¿discurso preventivo¿). Depois de discutir os resultados no contexto da literatura científica atual, o artigo oferece várias propostas para aumentar a percepção de risco entre os adolescentes: impacto mais forte de conteúdos sobre os riscos do álcool no curto prazo; estratégias educativas orientadas aos adolescentes para incluir os agentes da socialização, especialmente os pais, além de políticas centradas na substância e na redução da oferta.Departamento de Educación y Psicología SocialVersión del edito

    XIPE: the x-ray imaging polarimetry explorer

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    XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially- resolved X-ray polarimetry as a breakthrough in high energy astrophysics and fundamental physics. Indeed the payload consists of three Gas Pixel Detectors at the focus of three X-ray optics with a total effective area larger than one XMM mirror but with a low weight. The payload is compatible with the fairing of the Vega launcher. XIPE is designed as an observatory for X-ray astronomers with 75 % of the time dedicated to a Guest Observer competitive program and it is organized as a consortium across Europe with main contributions from Italy, Germany, Spain, United Kingdom, Poland, Sweden

    Evaluation of eye and skin irritation of arginine-derivative surfactants using different in vitro endpoints as alternatives to the in vivo assays

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    Arginine-derivative surfactants constitute a novel class of surfactants, which can be regarded as an alternative to conventional surfactants. Prior to human exposure, it is necessary to assess their irritation potential. The classical in vivo evaluation of the irritancy potential via the Draize test has been extensively criticized. In that regard, a great number of in vitro alternatives have been developed. Erythrocytes were chosen as the target cells for eye irritation assessment and hemolysis and hemoglobin denaturation were selected as appropriate endpoints. For skin irritancy assessment, the keratinocyte cell line NCTC 2544 was used and different in vitro endpoints were measured: two cytotoxicity assays (NRU and MTT) and the synthesis of the proinflammatory cytokine IL-1alpha. The eye and skin Draize tests were also performed for comparative purposes. The results point out that, according to in vivo and in vitro assays, the new arginine-derivative surfactants have lower eye and skin irritation potential than the synthetic surfactant SDS. Furthermore, in vitro methods were also able to detect differences in irritancy among the new surfactants not noticeable by the Draize tests, indicating that in vitro methods can be more sensitive than the in vivo test, offering the opportunity to detect subtle differences in irritanc

    Searching for the antioxidant, anti-inflammatory, and neuroprotective potential of natural food and nutritional supplements for ocular health in the mediterranean population.

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    Adherence to a healthy diet offers a valuable intervention to compete against the increasing cases of ocular diseases worldwide, such as dry eye disorders, myopia progression, cataracts, glaucoma, diabetic retinopathy, or age macular degeneration. Certain amounts of micronutrients must be daily provided for proper functioning of the visual system, such as vitamins, carotenoids, trace metals and omega-3 fatty acids. Among natural foods, the following have to be considered for boosting eye/vision health: fish, meat, eggs, nuts, legumes, citrus fruits, nuts, leafy green vegetables, orange-colored fruits/vegetables, olives-olive oil, and dairy products. Nutritional supplements have received much attention as potential tools for managing chronic-degenerative ocular diseases. A systematic search of PubMed, Web of Science, hand-searched publications and historical archives were performed by the professionals involved in this study, to include peer-reviewed articles in which natural food, nutrient content, and its potential relationship with ocular health. Five ophthalmologists and two researchers collected the characteristics, quality and suitability of the above studies. Finally, 177 publications from 1983 to 2021 were enclosed, mainly related to natural food, Mediterranean diet (MedDiet) and nutraceutic supplementation. For the first time, original studies with broccoli and tigernut (chufa de Valencia) regarding the ocular surface dysfunction, macular degeneration, diabetic retinopathy and glaucoma were enclosed. These can add value to the diet, counteract nutritional defects, and help in the early stages, as well as in the course of ophthalmic pathologies. The main purpose of this review, enclosed in the Special Issue "Health Benefits and Nutritional Quality of Fruits, Nuts and Vegetables," is to identify directions for further research on the role of diet and nutrition in the eyes and vision, and the potential antioxidant, anti-inflammatory and neuroprotective effects of natural food (broccoli, saffron, tigernuts and walnuts), the Mediterranean Diet, and nutraceutic supplements that may supply a promising and highly affordable scenario for patients at risk of vision loss. This review work was designed and carried out by a multidisciplinary group involved in ophthalmology and ophthalmic research and especially in nutritional ophthalmology
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