3,740 research outputs found

    Comparison of different small molecular weight alcohols for sustaining sulfidogenic bioreactors maintained at moderately low pH

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    Sulfate-reducing bacteria (SRB) catalyse the dissimilatory reduction of sulfate to hydrogen sulfide using a wide range of small molecular weight organic compounds, and hydrogen, as electron donors. Here we report the effects of different combinations of small molecular weight alcohols on the performance and bacterial composition of a moderately low pH sulfidogenic bioreactor (pH 4.0–5.5) operated at 35°C in continuous flow mode. Ethanol alone and methanol or ethanol used in combination with glycerol were evaluated based on their equivalent amounts of carbon. Although evidenced that methanol was utilised as electron donor to fuel sulfidogenesis at pH 5.5, rates of sulfate reduction/sulfide production were negatively impacted when this alcohol was first introduced to the system, though these rates increased in subsequent phases as a result of adaptation of the microbial community. Further increased dosage of methanol again caused rates of sulfidogenesis to decrease. Methanol addition resulted in perturbations of the bioreactor microbial community, and species not previously detected were present in relatively large abundance, including the sulfate-reducer Desulfovibrio desulfuricans. Ethanol utilization was evidenced by the increase in rates of sulfidogenesis as the dosage of ethanol increased, with rates being highest when the bioreactor was fed with ethanol alone. Concentrations of acetate in the effluent liquor also increased (up to 8 mM) as a result of incomplete oxidation of ethanol. This alcohol continued to be used as the electron donor for sulfate reduction when the bioreactor pH was decreased incrementally (to pH 4.0), but rates of sulfidogenesis decreased. The relative abundance of Dv. desulfuricans diminished as the bioreactor pH was lowered, while that of the acidophilic Firmicute Desulfosporosinus acididurans increased. This study has shown that all three alcohols can be used to fuel microbial sulfidogenesis in moderately acidic liquors, though the cost-effectiveness, availability and toxicity to the microbial community will dictate the choice of substrate

    Design and operation of empirical manganese-removing bioreactors and integration into a composite modular system for remediating and recovering metals from acidic mine waters

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    Packed bed bioreactors were used to remove soluble manganese from a synthetic mine water as the final stage of an integrated bioremediation process. The synthetic mine water had undergone initial processing using a sulfidogenic bioreactor (pH 4.0–5.5) which removed all transition metals present in elevated concentrations (Cu, Ni, Zn and Co) apart from manganese. The aerobic bioreactors were packed with pebbles collected from a freshwater stream that were coated with black-colored, Mn(IV)-containing biofilms, and their capacity to remove soluble Mn (II) from the synthetic mine water was tested at varying hydraulic retention times (11–45 h) and influent liquor pH values (5.0 or 6.5). Over 99% of manganese was removed from the partly processed mine water when operated at pH 6.5 and a HRT of 45 h. Molecular techniques (clone libraries and T-RFLP analysis) were used to characterize the biofilms and identified two heterotrophic Mn-oxidizing microorganisms: the bacterium Leptothrix discophora and what appears to be a novel fungal species. The latter was isolated and characterized in vitro

    System design perspective of healthcare provision in humanitarian aid

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    This study focuses on the role of Systems Design in addressing the challenges of healthcare provision by international emergency relief organizations in developing countries. More specifically the challenges related with the safety and performance of medical devices that are transferred in the aftermath of a humanitarian crisis. Our aim is to describe this transfer on the basis of two field studies in Indonesia and Haiti and reflect on the value of Human Factors and Ergonomics for a Systems Design approach. The presented concepts support designers in handling a larger degree of complexity and support them to think more steps ahead in a design project. Future studies will involve collaborative design projects dedicated to bring this reflection further to the development of healthcare products and services

    Methodology to design an economic and strategic offshore wind energy Roadmap in Portugal

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    The main objective of this paper is to establish a roadmap for offshore wind energy in Portugal. It will determine the best sea areas to install fixed and floating offshore wind farms in this region, using spatial analysis of four economic indexes: Internal Rate of Return (IRR), Net Present Value (NPV), Discounted Pay-Back Period (DPBP) and Levelized Cost Of Energy (LCOE). Several economic parameters will be considered (Portuguese offshore tariff, investment and O&M costs, credit values, etc.).Three different discount rates were used into the sensitivity analysis. Several types of physical restrictions will be taking into account: submarine electrical cables, bathymetry, seabed geology, environmental conditions, protected areas in terms of heritage, navigation areas, seismic fault lines, etc. Moreover, location settings as proximity to shipyards or ports will be considered to complement the strategy. All of them will define the resulting area to install offshore wind farms along Portuguese coast. Spatial operations, considering economic, physical and strategic issues, have been carried out using Model Builder of GIS (Geographic Information Systems) software. Results indicate the Portuguese areas economically suitable for installing offshore wind farms

    Family relations, parents’ educational practices, and Angolan adolescents’ values

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    The purpose of this study was three-fold. First, to analyze psychometric properties of the instruments used to evaluate the perceived Family relations, Familiar socialization and Angolan adolescents’ Values. Second, to predict the adolescents’ Values based on Family relations and Family socialization.Third, to analyze adolescents’ Values sex differences. For this aim, 917 adolescents (384 males, 533 females) ages 14 to 17 years (M = 15.68; SD = 1.06)completed Portuguese translations of the Family relations, Family socialization and Value questionnaires. When psychometric properties of the instruments were assessed, a Structural Equation Model (SEM) controlling for sex was carried out, with Family relations and Family socialization as independent variables, and adolescents’ Values as dependent variables. Results showed acceptable psychometric properties of the Portuguese versions of the instruments. Related to the SEM, Familiar functioning predicted Achievement, Universalism, Securityand Conformity; Parents’ Support predicted Benevolence and Conformity; Family difficulties were negatively related with Achievement and Conformity; and Punishment/coercion were negatively related with Achievement, Benevolence and Conformity. The sex variable only differentiated two adolescents’ values. Boys assigned priority to Universalism and girls assigned priority to Conformity. These findings are discussed with regard to the implications to adolescents’ socialization

    Effect of redox potential on chalcopyrite dissolution imposed by addition of ferrous ions

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    Copper is a metal with a great economic interest and about 70% is found in nature in chalcopyrite form (CuFeS2). However the chalcopyrite dissolution is a challenge for industries as well as researchers because of its slow dissolution kinetics. The control of redox potential is one factor that can help in this drawback. This study was undertaken to evaluate the role of redox potential on chalcopyrite bioleaching by addition of ferrous ions. Acid leaching with addition of ferrous ions promoted high dissolution of chalcopyrite by the maintenance of low redox potential (420 mV/Ag/AgCl). On the other hand, the copper dissolution in bacterial systems showed low copper recovery (610 mV/Ag/AgCl). XRD of solid residues showed in abiotic conditions the formation of elemental sulfur, jarosites and a significant decrease on chalcopyrite’s peaks. In bacterial conditions, only jarosites was detected as new crystalline phase. SEM analysis confirmed the results obtained by XRD. In general, the results showed conclusive evidence that the maintenance of low redox potential and the addition of ferrous ions have positively influenced the copper recovery and confirmed the literature data, which indicate a critical potential range where chalcopyrite leaching is more favorable.</jats:p

    a intervenção do enfermeiro de saúde mental

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    Atualmente a percentagem de pessoas com doença mental tem vindo a aumentar, sendo frequente encontrar pessoas com ansiedade, agressividade e/ou agitação psicomotora, internadas em unidades de cuidados intensivos. É necessário intervir junto destas, de modo a dar-lhes atenção, proporcionar a expressão de sentimentos, o esclarecimento de dúvidas, de modo a compreender as significações da experiência do internamento e ajudá-las na identificação das suas necessidades. De modo a colmatar uma necessidade sentida na prática clínica, o presente relatório foi desenvolvido tendo por base a dimensão relacional da prática de enfermagem, nomeadamente, na empatia enquanto característica do enfermeiro promotora da relação terapêutica com a pessoa com doença mental. Este tema surge da interseção de duas áreas de prestação de cuidados distintas: doente crítico e saúde mental e psiquiatria. Estabelecer uma relação terapêutica com a pessoa com doença mental, requer que o enfermeiro desenvolva competências humanas e técnicas específicas, sustentadas em teorias atuais, nomeadamente a Teoria das Relações Interpessoais de Hildegard Peplau. Com a realização do estágio, em contexto de Hospital de Dia e internamento de psiquiatria de agudos, pretendeu-se consolidar competências no relacionamento terapêutico com a pessoa com doença mental através do exercício autorreflexivo. Foram desenvolvidas atividades de grupo e individuais, que permitiram pensar a empatia na relação terapêutica, contribuindo para aumento do conhecimento na práxis de enfermagem. O caminho percorrido na área da saúde mental e psiquiatria foi um desafio pessoal e profissional, que contribuiu positivamente para o desenvolvimento consistente das competências específicas de Enfermeira Especialista em Enfermagem de Saúde Mental e Psiquiatria

    Seal Appeal: uma produção audiovisual de animação em 3D para a conscientização sobre a poluição do oceano, modelação 3D e captura de movimento

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    Desde o final do século XX, as técnicas de animação têm sido amplamente utilizadas em produções, anúncios, filmes, publicidade, efeitos visuais e assim por diante, e se tornaram uma parte indispensá vel do cinema e da televisão. O rápido crescimento da tecnologia e seu impacto em toda a indústria de produção permitiu que as técnicas de animação geradas por computador se tornassem variadas e generalizadas. As técnicas de animação por computador não só economizam trabalho e dinheiro, mas também dão ao produtor a opção de aplicar a técnica em duas dimensões (2D) ou tridimensio nais (3D), dependendo do período de tempo, cenário e conteúdos dados. Existe uma vasta gama de softwares e hardwares disponível tanto para a produção de uma animação 3D como para a captura de movimento, com valores bastante acessíveis ou até mesmo gratuitos que torna a criação pessoal de uma animação tridimensional possível. Assim, neste projeto foi encontrada uma solução acessível para a produção de uma curta-metragem de animação em 3D com o objetivo de conscientizar o pú blico em geral para o problema da poluição do oceano. Foi seguida uma metodologia própria para a realização deste projeto dividida em três fases tais como pré-produção - constituída por idealização, criação de um guião, de um storboard e finalmente, design dos conceitos visuais; produção - onde foi realizada toda a modelação, texturização, rigging e animação; e por último, pós-produção - constituí- da por edição de vídeo, áudio e efeitos visuais 2D. Desde modo, o resultado final do projeto foi uma curta-metragem de animação 3D criada com o uso de ferramentas acessíveis.Since the end of the 20th century, animation techniques have been widely used in productions, ad vertisements, films, advertising, visual effects and so on, and have become an indispensable part of cinema and television. The rapid growth of technology and its impact on the entire production industry has allowed computer-generated animation techniques to become varied and widespread. Computer animation techniques not only save labor and money, but also give the producer the option of applying the technique in two dimensions (2D) or three dimensional (3D), depending on the time period, scenario and content given. There is a wide range of software and hardware available both for the production of a 3D animation and for the capture of motion, with very accessible or even free values that makes the personal creation of a three-dimensional animation possible. Thus, in this project an accessible solu- tion was found for the production of a 3D animation short film with the objective of raising the general public’s awareness of the problem of ocean pollution. A specific methodology was followed to carry out this project, divided into three phases such as pre-production - consisting of idealization, creation of a script, a storboard and finally, design of visual concepts; production - where all modeling, texturing, rigging and animation was carried out; and finally, post-production - consisting of video editing, audio and 2D visual effects. In this way, the final result of the project was a 3D animation short film created using accessible tools
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