776 research outputs found

    Nanoparticles as vectors of other contaminants in estuarine suspended sediments: Natural and real conditions

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    Studding the behaviour and danger of nanoparticles (NPs, minerals and amorphous phases) in the estuarine ecosystem is presently incomplete by the lack of measureable description of NPs in the ecological conditions, such as suspended-sediments (SS). In the last years, several works have revealed the toxic consequences of ultra-fine and nanoparticulate compounds on diverse systems, raising apprehensions over the nanocontaminants behaviour and destiny in the numerous ecological partitions. The general objective of the manuscript is to explain the geochemical conditions of the LES (Laguna estuarine system, southern Brazil) suspended sediments covering an area around the main South American coal plant, enhancing the creation of future public policies for environmental recovery projects. Subsequently the discharge of nanoparticles and toxic element (TE) in the ecosystem, NPs react with several constituents of the nature and suffers active alteration progressions. Contamination coming from engineering actions, wastewater, are something identifiable, however when these contaminations are accompanied by other contamination sources (e.g. mining and farming) the work gets defaulted. By combining material about the concentration of TE contaminants and NPs occurrences, this work offers novel visions into contaminant contact and the possible effects of such exposure on estuarine systems in Brazil. The results presented here will be useful for different areas of estuaries around the world

    Environmental aspects of the depreciation of the culturally significant Wall of Cartagena de Indias – Colombia

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    Among the diverse archeological relics of the past, the Cartagena de Indias Wall is one of the greatest representations of European cultural architecture in South America. To assess the implication of contamination on the depreciation of the culturally significant Wall of Cartagena de Indias - Colombia, a detailed, multi-analytical approach was conducted on components of the wall. Accumulated ultra-fine particles (UFPs) and superficial nano-particles (NPs) containing hazardous elements (HEs) on the wall were identified in an attempt to understand whether atmospheric pollution is hastening the depreciation of the structure itself. Mortar which at one point held the stones together is now weak and has fallen away in places. Irreparable damage is being done by salt spray, acid rain and the site's tropical humid climate. Several HEs and organic compounds found within the local environment are also contributing to the gradual deterioration of the construction. In this study, advanced microscopy analyses have been applied to understand the properties of UFPs and NPs deposited onto the wall's weathered external walls through exposure to atmospheric pollution. Several materials identified by X-Ray Diffraction (XRD) can be detected using high-resolution transmission electron microscopy (HR-TEM) and field emission scanning electron microscope (FE-SEM). The presence of anglesite, gypsum, hematite containing HEs, and several organic compounds modified due to moisture and contamination was found. Black crusts located on the structure could potentially serve as a source of HEs pollution and a probable hazard to not only to the ecosystem but also to human health

    Nanoparticles and interfaces with toxic elements in fluvial suspended sediment

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    Studies examining nanoparticles (NPs) and hazardous elements (HEs) contained in suspended sediments (SSs) are vital for watershed administration and ecological impact evaluation. The biochemical consequence of titanium-nanoparticles (Ti-NPs) from SSs in Colombia's Magdalena River was examined utilizing an innovative approach involving nanogeochemistry in this study. In general, the toxicity and the human health risk assessment associated with the presence of some Ti-NPs + HEs in SSs from riverine systems need to be determined with a robust analytical procedure. The mode of occurrence of Ti-NPs, total Ti and other elements contained within SSs of the Magdalena River were evaluated through advanced electron microscopy (field emission scanning electron microscope-FE-SEM and high resolution transmission electron microscope-HR-TEM) coupled with an energy dispersive X-ray microanalysis system (EDS); X-Ray Diffractions (XRD); and inductively coupled plasma-mass spectrometry (ICP-MS). This work showed that enormous quantities of Ti-NPs were present in the river studied and that they displayed diverse geochemical properties and posed various possible ecological dangers. Ti-NP contamination indices must be established for measuring the environmental magnitudes of NP contamination and determining contamination rank among rivers. Finally, SS contamination guidelines must be recommended on an international level. This study contributes to the scientific understanding of the relationship of HE and Ti-NP dynamics from SSs in riverine systems around the world

    Bis(tetra­phenyl­phospho­nium) bis­[N-(octyl­sulfon­yl)dithio­carbimato(2–)-κ2 S,S′]­nickelate(II)

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    The Ni atom in the title complex, (C24H20P)2[Ni(C9H17NO2S3)2], lies on a twofold axis within a square-planar geometry defined by four S atoms derived from two dithio­carbimate dianions, each forming a four-membered chelate ring. A small distortion, described by a deviation of the NiII atom by 0.083 (1) Å from the plane through the four S atoms, and also by the torsion angles about the Ni—S bonds, implies a folded conformation for the chelate ring

    Conversion of MDF wastes into a char with remarkable potential to remove Food Red 17 dye from aqueous effluents

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    Medium density fiberboard (MDF) wastes were converted into an efficient char able to uptake Food Red 17 dye (FR17) from colored effluents. The yield of the pyrolysis process, in terms of char, was 29%. The produced char presented micro and mesoporous, with surface area of 218.8 m2 g−1 and total pore volume of 0.122 cm3 g−1. Regarding to the FR17 adsorption, removal percentages of 90% were found at pH 2 and using 0.5 g L−1 of char. Pseudo–first and pseudo–second order models were adequate to represent the adsorption kinetic profile, being the equilibrium reached within 20 min. Freundlich model was selected to represent the equilibrium data. The maximum adsorption capacity was 210 mg g−1. The adsorption of FR17 on the char was endothermic and physical in nature. The char was efficient for 8 adsorption–desorption cycles, maintaining the same adsorption capacity. In brief, this work demonstrated a useful practice in terms of cleaner production. It was possible add value to MDF wastes, generating an efficient and reusable adsorbent to treat colored effluents containing FR 17 dye

    Nanoparticles in fossil and mineral fuel sectors and their impact on environment and human health: A review and perspective

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    Nanoscience and technology have enabled better insights into the environmental and health impacts arising from the mining, production and use of fossil and mineral fuels. Here we provide an overview of the nanoscience-based applications and discoveries concerning coal and mineral fuel (i.e., uranium-containing minerals) mining, refining/production, use, and disposal of wastes. These processes result in massive nanoparticle release and secondary nanoparticle generation which have highly significant environmental implications and human health consequences on local, regional, and even global levels. Until recently, very little was known about nanoparticle fractions. Recent advancements and sophistications enable us to detect, collect and study these materials which are roughly 1 nm (0.001 µm) up to several tens of nanometers in size. These materials are known to behave differently (chemically, electrically, and mechanically), relative to their macroscopic equivalents. This is what makes nanoscience fascinating and difficult to predict, underscoring the importance of this emerging new field. For example, nanoparticles associated with coal and mineral fuel influence the release, uptake, and transportation of hazardous elements associated with mining, processing, and waste storage in the surrounding areas. This includes long distance transport down streams, rivers, and eventually to oceans such as from coal and uranium mine drainages. In terms of human health, in all phases of mining, production/refining, use, and waste disposal, the associated nanoparticles can be acquired through oral ingestion, inhalation, and dermal absorption. Inhalation has been shown to be particularly damaging, where lung, heart, kidney, and brain diseases are prevalent. Relative to all other fields of science and engineering associated with coal and mineral fuel mining, production, use, and clean-up efforts, nanoscience, although a much newer field then the rest by comparison, is still greatly under-represented and under-utilized. There is also a continuing gap between what we so far know about the behavior of nanoparticles, and what remains to be discovered

    Automatic subject-based contextualisation of programming assignment lists.

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    As programming must be learned by doing, introductory programming course learners need to solve many problems, e.g., on systems such as ’Online Judges’. However, as such courses are often compulsory for non-Computer Science (nonCS) undergraduates, this may cause difficulties to learners that do not have the typical intrinsic motivation for programming as CS students do. In this sense, contextualised assignment lists, with programming problems related to the students’ major, could enhance engagement in the learning process. Thus, students would solve programming problems related to their academic context, improving their comprehension of the applicability and importance of programming. Nonetheless, preparing these contextually personalised programming assignments for classes for different courses is really laborious and would increase considerably the instructors’/monitors’ workload. Thus, this work aims, for the first time, to the best of our knowledge, to automatically classify the programming assignments in Online Judges based on students’ academic contexts by proposing a new context taxonomy, as well as a comprehensive pipeline evaluation methodology of cutting edge competitive Natural Language Processing (NLP). Our comprehensive methodology pipeline allows for comparing state of the art data augmentation, classifiers, beside NLP approaches. The context taxonomy created contains 23 subject matters related to the non-CS majors, representing thus a challenging multi-classification problem. We show how even on this problem, our comprehensive pipeline evaluation methodology allows us to achieve an accuracy of 95.2%, which makes it possible to automatically create contextually personalised program assignments for non-CS with a minimal error rate (4.8%)

    Information processing among high-performance managers

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    O propósito deste estudo foi avaliar o processamento da informação de 43 gestores empresariais de desempenho superior. No seu enquadramento teórico recorremos a três modelos: a Teoria dos Papéis Gerenciais de Henry Mintzberg, a Teoria do Processamento da Informação e o Modelo de Processo de Resposta ao Rorschach de John Exner. A ava-liação dos sujeitos recorreu ao método do Rorschach. Os resultados deste estudo mos-traram que esses gerentes são capazes de recolher dados, avaliá-los e estabelecer ran-kings de maneira adequada. Ao mesmo tempo, verifica-se que são capazes de ser objeti-vos e precisos na avaliação dos problemas. Este estilo de processamento de informação possibilita uma interpretação do mundo a partir de um modo de processamento ou de um estilo cognitivo, próprio e característico.The purpose of this study was to evaluate the information processing of 43 business managers with a professional superior performance. The theoretical framework consid-ers three models: the Theory of Managerial Roles of Henry Mintzberg, the Theory of In-formation Processing, and Process Model Response to Rorschach by John Exner. The participants have been evaluated by Rorschach method. The results show that these managers are able to collect data, evaluate them and establish rankings properly. At same time they are capable of being objective and accurate in the problems assessment. This information processing style permits an interpretation of the world around on basis of a very personal and characteristic processing way or cognitive style.Fundação para a Ciência e a Tecnologia (FCT), no âmbito do Fundo de Apoio à Comunidade Científica - Edição de Publicações Periódicas de Natureza Científica

    Influência de rotações de culturas nas propriedades físico-hídricas de um Latossolo Vermelho em plantio direto.

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    A adoção do plantio direto, com a inclusão de espécies gramíneas de relação C/N alta, poderá minimizar a degradação estrutural do solo. O objetivo deste trabalho foi avaliar a influência da inclusão da braquiária na rotação de culturas nas propriedades físico-hídricas e no conteúdo de matéria orgânica de um Latossolo Vermelho distrófico em plantio direto. O delineamento experimental foi o de blocos ao acaso, em parcelas subdivididas, com quatro repetições. As parcelas foram compostas por quatro sistemas de rotação, e as subparcelas, por quatro profundidades de amostragem (0-10; 10-20; 20-40, e 40-60 cm). As culturas utilizadas foram: arroz (A); feijão irrigado (F); milho (M); soja (S), e arroz (A+B), milho (M+B) e soja (S+B) consorciados com braquiária. Os sistemas de rotação foram: S1 - A/F/M/F/S/F; S2 - A+B/F/M+B/F/S+B/F; S3 - M/F/S/F/S/F, e S4 - M+B/F/S+B/F/S+B/F. Uma área de mata nativa, situada a 500 m do experimento, foi considerada como controle. A inclusão da braquiária na rotação de culturas não afetou a densidade, a macroporosidade e a capacidade de água disponível do solo. A porosidade total e o teor de matéria orgânica do solo foram favorecidos pelas rotações que incluíam maior número de cultivos de soja. A associação de soja com a braquiária contribuiu para a estabilidade dos agregados, e a de gramíneas de verão com a braquiária, para a diminuição da resistência do solo à penetração

    Medical students, spirituality and religiosity-results from the multicenter study SBRAME

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    Background: To evaluate the relationship between spirituality/religiosity (S/R) and the attitudes, beliefs and experiences of medical students in Brazil with respect to S/R in their undergraduate training and clinical practice.Methods: SBRAME (Spirituality and Brazilian Medical Education) is a multicenter study involving 12 Brazilian medical schools with 5950 medical students (MS). Participants completed a questionnaire that collected information on socio-demographic data and S/R in their undergraduate training and practice.Results: of all MS, 3630 participated in the survey (61.0%). the sample was 53.8% women and the mean age was 22.5 years. the majority of MS believed that spirituality has an impact on patients' health (71.2%) and that this impact was positive (68.2%). the majority also wanted to address S/R in their clinical practice (58.0%) and considered it relevant (75.3%), although nearly one-half (48.7%) felt unprepared to do so. Concerning their training, most MS reported that they had never participated in a spirituality and health activity (81.0%) and that their medical instructors had never or rarely addressed this issue (78.3%). the majority also believed that they should be prepared to address spiritual issues related to the health of their patients (61.6%) and that this content should be included in the medical curriculum (62.6%).Conclusion: There is a large gap between MS attitudes and expectations and the S/R training that they are receiving during their undergraduate training. the majority of MS surveyed believe that patients should have their beliefs addressed and that these beliefs could have important effects on their health and the doctor-patient relationship. These results should stimulate discussion about the place that S/R training should have in the medical curriculum.Univ Fed Juiz de Fora, Juiz de Fora, BrazilBrazilian Med Spiritist Assoc, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilDuke Univ, Med Ctr, Durham, NC USAKing Abdulaziz Univ, Jeddah 21413, Saudi ArabiaUniversidade Federal de São Paulo, São Paulo, BrazilWeb of Scienc
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