4,299 research outputs found
Maintenance and distribution of mammalian mitochondrial nucleoids
Mitochondria derive from the capture of an ancestral α-proteobacteria within an archaeal cell about 2 billion years ago. Since then mitochondria have retained a small proportion of genes within their multi-copy genome mitochondrial DNA (mtDNA) that encode proteins essential to the oxidative phosphorylation system. They have also evolved into a major metabolic hub in eukaryotic cells. Many biosynthetic pathways require mitochondria such as the synthesis of iron-sulfur clusters, heme, lipids and coenzyme Q. However, mitochondria are best known for their efficient ATP production through aerobic metabolism.
The mitochondrial network is a dynamic structure. Through coordinated actions of membrane fusion and fission, mitochondria are able to remodel their shapes and sizes, but also their distribution within the cell. Mitochondrial dynamics is an essential process that impacts mammalian physiology in many different ways. One of the clearest examples is the relationship between mitochondrial fusion and mtDNA maintenance. In animal studies, the absence of mitochondrial fusion proteins resulted in severe reduction in mtDNA copy number. Moreover, loss of mitochondrial fusion proteins, mitofusins, was also associated with an increase in mtDNA point mutations and deletions. However, the molecular basis of these findings is poorly understood.
The research presented in this thesis aims to address the underlying link between mitochondrial fusion and mtDNA maintenance. We report that inactivation of mitofusin 1 and 2 leads to mtDNA depletion and nucleoid clustering in mouse embryonic fibroblasts and heart tissue. With super-resolution microscopy and fluorescent in situ hybridization, we show that clustered nucleoids have normal diameters and are transcribed. We report that the loss of mtDNA accounts for the reduction in transcription and bioenergetic defects. Moreover, we demonstrate that the profound mtDNA depletion is not explained by genome instability, but instead it is caused by altered stoichiometry of protein components of the mtDNA replisome. Lastly, we show that outer membrane fusion is necessary to sustain rapid mtDNA replication in MEFs recovering from mtDNA depletion and in the mouse heart during postnatal development. We thus report an unexpected link between OMM fusion and replication and distribution of mtDNA in mammalian cells
Escola livre de teoria musical
A Escola Livre de Teoria Musical pretende enfrentar a falta de oferta de conhecimentos qualificados em música na região de Foz do Iguaçu. Num contexto de forte estratificação social, o conhecimento musical é oferecido apenas em escolas particulares ou associações, que os fornecem preferencialmente aos seus membros. Pretende-se, com o presente projeto, difundir o conhecimento musical na comunidade, atrair possíveis alunos para a UNILA e auxiliar, nessa atividade extracurricular, alunos com dificuldades, dispondo-os como monitores ou mesmo como alunos do projeto. Para tanto, neste semestre, duas turmas foram abertas, uma durante a semana, no período noturno, e outra com aulas aos sábados, no período vespertino, com duração ampliada, o que possibilita atender a diferentes segmentos da comunidade, com dinâmicas de aprendizado e disponibilidade de tempo variada. Ambas as turmas são de nível básico e entre os alunos nota-se forte diversidade, incluindo desde discentes da UNILA que não cursam música, bem como da comunidade trinacional, incluindo músicos práticos que não possuíam instrução formal sobre a música, oriundos de grupos religiosos. Nota-se também faixa etária significativamente ampla entre os matriculados nos cursos da Escola. Com o exposto, parece adequado afirmar que a Escola Livre de Teoria Musical vem cumprindo com seus objetivos iniciais, apoiando a democratização do acesso ao conhecimento musical de qualidade junto à comunidade de Foz do Iguaçu e região e atuando como ponte entre academia e sociedade
Jornalismo impresso protestante e suas relações de poder no processo de consolidação da república brasileira : a comunicação-político-religiosa nas páginas do jornal "O Estandarte"
Orientador :Monografia (especialização) - Universidade Federal do Paraná, Setor de ..., Curso de Especialização em ...Inclui referência
Esforço tributário e interação estratégica dos governos municipais : uma análise com modelos geograficamente ponderados
Orientador : Prof. Dr. Alexandre Alves PorsseDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciencias Sociais Aplicadas, Programa de Pós-Graduação em Desenvolvimento Ecônomico. Defesa : Curitiba, 31/03/2016Inclui referências : f. 74-79Resumo: O imposto sobre circulação de serviços de qualquer natureza (ISS) e o imposto sobre a propriedade predial e territorial urbana (IPTU) são os dois tributos mais importantes na arrecadação municipal, de maneira que dada a sua maior discricionariedade em relação às demais fontes de receita, é possível que os municípios brasileiros se engajem em algum tipo de comportamento estratégico visando atender seus interesses individuais. Este estudo utiliza a abordagem de regressões ponderadas geograficamente para investigar se existe interação espacial e heterogeneidade no comportamento estratégico dos governos municipais quanto à arrecadação dos tributos ISS e IPTU para os anos 2000 e 2010. Investiga-se também como o esforço tributário municipal se comporta nesse contexto, levando-se em consideração as transferências intergovernamentais na composição da receita final dos municípios. Os resultados apontam para a existência de interação estratégica na determinação das alíquotas efetivas dos dois tributos, bem como influência negativa das transferências sobre o esforço tributário municipal. No entanto, o comportamento estratégico e o efeito das transferências sobre o esforço tributário são espacialmente heterogêneos e se modificam entre 2000 e 2010. No caso do ISS, o comportamento estratégico em 2000 era espacialmente heterogêneo e tornou-se homogêneo em 2010. No caso do IPTU, esse efeito é espacialmente heterogêneo tanto em 2000 como em 2010, concentrando-se mais na vizinhança de grandes centros urbanos das regiões Sudeste e Sul. Palavras-chave: Interação estratégica, regressão ponderada geograficamente, esforço tributário, competição interjurisdicional.Abstract: The municipal service tax (ISS) and the municipal property tax (IPTU) are two of the most important taxes in municipal tax revenue. Given their greater discretion relating to other revenue sources, it is possible that Brazilian municipalities engage in some kind of strategic behavior to meet their individual interests. This study employs a geographically weighted regression approach to investigate whether there is interaction and spatial heterogeneity or not in the strategic behavior of local governments in the collection of ISS and IPTU taxes for the years of 2000 and 2010. It also investigates how the municipal tax effort behaves in this context, taking into account the intergovernmental transfers in the composition of the municipalities' final revenues. The results point to the existence of strategic interaction in determining the effective rates of the two taxes, as well as a negative influence of transfers on municipal tax effort. However, the strategic behavior and the effect of transfers on the tax effort are spatially heterogeneous and distinct between 2000 and 2010. In the case of ISS, the strategic behavior in 2000 was spatially heterogeneous and became homogeneous in 2010. In the case of the property tax, this effect is spatially heterogeneous in both 2000 and 2010, focusing more in Southeastern and Southern large cities vicinity. Keywords: Strategic Interaction, geographically weighted regression, tax effort, interjurisdictional competition
A RELAÇÃO ENTRE O IGC E O PROJETO PEDAGÓGICO INSTITUCIONAL: REFLEXÕES A PARTIR DE UMA ANÁLISE DO PDI EM FACULDADES ISOLADAS
O artigo versa sobre um estudo que tem a intenção de apresentar as principais ações que confirmam a relação entre o IGC e o PDI na perspectiva do Projeto Pedagógico Institucional no contexto de Faculdades Isoladas localizadas no sul do estado de Santa Catarina. No escopo teórico, a pesquisa elenca aspectos que contextualizam a estrutura das faculdades isoladas, considerando a expansão proporcionada a partir de 1996 sob o advento da LDB. Elenca, ainda, considerações sobre o PDI e sua estrutura dinâmica de seus eixos, os quais são responsáveis pelo desenvolvimento das questões operacionais e estratégicas das instituições. O trabalho, ainda em seu escopo teórico, traz assertivas que consideram o IGC um referencial no contexto avaliativo e regulatório, orientando as atividades acadêmicas e administrativas em nível institucional. A metodologia, para tanto, se esmera em uma pesquisa predominantemente qualitativa, considerando uma entrevista semi-estruturada como instrumento de coleta de dados, utilizando, também, bases da pesquisa descritiva e explicativa no contexto metodológico. Os resultados permitem concluir, entre outros aspectos, que o IGC traz influencia no PPI das Instituições e orienta um processo de reflexão sobre o desenvolvimento institucional
How can management scholars contribute with research in the COVID-19 crisis?
IntroductionAs the Covid-19 crisis ensues throughout the world, researchers from several fields of research consider how they could contribute to the current understanding of the crisis. In the field of strategic management, we face a special problem as most companies scraped their strategic plans for the year 2020 as they are currently more focused on surviving the crisis with emergent strategies. Strategic management researchers are now in a position where their main object of research has been highly influenced by the pandemic and face the challenge of developing impactful and meaningful research in a world where all eyes are looking for answers to the crisis.In the Iberoamerican Journal of Strategic Management, we decided that we would encourage researchers in our field to develop research that contributes to a better understanding of the pandemic crisis and their impacts on organizations. We are not currently announcing a special issue dedicated to the pandemic crisis. However, we are stating that we welcome and encourage research on the investigation of aspects that link the pandemic to organizations and strategy.We believe that it is crucial for researchers to acknowledge and to understand the impacts that the pandemic crisis has on organizations. The more we understand this crisis, the more we can contribute to reducing the effects it will have on organizations and jobs. Besides, we believe that this is a time when we, as researchers, have to contribute to society by helping in every way we can. The best way to contribute with our skills is to provide a better understanding of how, in which conditions, and to what extent the pandemic crisis will influence organizations.We provide two following sections for this editorial. First, a suggestion of research themes to be addressed, and secondly, a section regarding the cautions we must have when researching the effects of the pandemic crisis. Suggestions of research themes Impacts of the pandemic crisis over firm performance. Some works are already looking into how the pandemic crisis will impact firm performance (Aifuwa et al., 2020; Gonzalez-Uribe & Wang, 2020). This is a very important topic as the economic performance of the world will be hindered by the crisis. It is important not only to understand how the pandemic will reduce the performance of firms but also to investigate under which conditions this reduction will happen, in which industries, and depending on which firm-specific settings. Strategic responses to the pandemic crisis. Which strategies have firms put up to deal with the crisis? Which kinds of strategic moves have been successful and reduced the impact of the crisis? How could these strategies shape businesses in the near future? It is especially interesting to investigate if firms can develop capabilities through the crisis and how these capabilities willshape future strategies. Global value chains and the pandemic. As companies throughout the world will have to deal with the disruption of global value chains during the pandemic (Bonadio et al., 2020), it is important to investigate how this disruption could shape the future of global value chains. Will companies diversify their value chains to avoid future problems in similar situations? What have we learned with the challenges of finding alternatives and dealing with disruptions of the chain? Institutional pressures, adaptation, and conformity in times of pandemics. Institutions are crucial for strategic decisions and the following performance of firms. However, the institutional environment is usually perceived as the rules of the game that change in a very slow fashion (North, 1990). The challenges that the pandemic crisis imposed upon firms have greatly changed the way that business is conducted. But are institutional pressures reinforced or loosened during a crisis as the pandemic? Could the pandemic crisis spark an institutional change? Pandemic-driven stress and its effects on decision-making. Organizations already struggle to maintain acceptable levels of strategic decision-making in normal circumstances, and in situations such as the current one, this becomes even more complex, subjective, and difficult. Decision-making is the cornerstone of most schools of thought in strategy, and crises escalate choices and consequences (Oroszi, 2018). Latin American organizations are sometimes considered more vulnerable in a plethora of dimensions, and the ongoing pandemic is most likely to influence decision-making in the area negatively. Teams, coordination and multinational efforts. Crises stir trouble but also provide interesting aspects worth of studying for teams and coordination (Driskell et al., 2018). Whereas technologies may mitigate the negative effects of the pandemic on team coordination, new ways of organizing work and making group efforts and decisions may also come up. Multiple stakeholders and conflicts in decision-making. Critical times impose extreme pressures not only on teams but also on stakeholders, especially external ones. Current literature still has gaps on conflicts between ideas as competing pressures and crises tend to overemphasize and distort stakes (van der Wal, 2020). Born globals, startups, and innovation in times of crisis. What are the effects – both negative and positive – of crises on innovation? More specifically, what happens to supposedly more vulnerable beginning endeavors such as born globals (Pepelasis & Protogerou, 2018) and startups (Haase & Eberl, 2019)? What are the capabilities they have developed or are seeking in order to survive these troubling times? SME Entrepreneurship and frugal innovation. As with born globals and startups, we must look to the opposite end of the scale. How are small and medium organizations dealing with the effects of the current crisis? Are there any behavior shifts and strategic alterations that can subside such negative consequences?Countercyclical industries and fields during crises. In the Iberoamerican territories, are there any industries and fields that are gaining momentum in a countercyclical fashion? What are these and what features do they have to promote growth? Can this growth be sustainable once the crisis subsides? Agroindustrial and low-tech industries may be examples, but other fields can also shed light on the matter (Martins et al., 2019). Cautions for researching the pandemic crisis As the pandemic crisis is still undergoing as we write this editorial, we thought of providing some guidance about the special care researcher must-have when dealing with this delicate issue. These are ethical guidelines that we see as important to be followed to ensure a meaningful discussion in the academic field. Do not put a value on lives and health. It is impossible to put a value on life. As researchers of the management field, we are focused on understanding the effects of the pandemic on organizations. We have seen statements treating the crisis as a tradeoff between lives and jobs, or between health and the economy. We are not in a position of pointing a side in this situation. We advise researchers always to remember that lives are invaluable. Do not step outside of your field of research. Many scholars from several fields have conducted research trying to understand and predict the spread of the Covid-19 disease, mainly using their skills with data. This effort is remarkable; however, this is not a competence of the management field as we are not trained in understanding diseases. We, therefore, encourage researchers to look at the effects of the crisis in organizations, and we advise not to delve into understanding the disease per se as this is not our expertise. Do not guide the research question by political agendas. We understand that there are many political interests regarding the results of research on the crisis. We also understand that it is tempting to answer direct questions posed by politicians in the issue. However, we advise scholars not to directly tackle into answering politically-driven questions and to maintain the impartiality we always have. Do not twist your theory/method/argumentation to fit a crisis. As of now, we see a surge on pandemic-related research on all fields. While in some fields this is expected (such as epidemiology or economics), not all management research is closely related to the topic. Several fields have also seen a surge in pandemic-framed research that is only marginally tangential to the topic – management included. Reshaping your study to fit the crisis it does not directly relate to is not only intellectually dishonest but also takes space and time from editors and reviewers from doing their job on papers that actually can contribute to the ongoing scenario.IntroductionAs the Covid-19 crisis ensues throughout the world, researchers from several fields of research consider how they could contribute to the current understanding of the crisis. In the field of strategic management, we face a special problem as most companies scraped their strategic plans for the year 2020 as they are currently more focused on surviving the crisis with emergent strategies. Strategic management researchers are now in a position where their main object of research has been highly influenced by the pandemic and face the challenge of developing impactful and meaningful research in a world where all eyes are looking for answers to the crisis.In the Iberoamerican Journal of Strategic Management, we decided that we would encourage researchers in our field to develop research that contributes to a better understanding of the pandemic crisis and their impacts on organizations. We are not currently announcing a special issue dedicated to the pandemic crisis. However, we are stating that we welcome and encourage research on the investigation of aspects that link the pandemic to organizations and strategy.We believe that it is crucial for researchers to acknowledge and to understand the impacts that the pandemic crisis has on organizations. The more we understand this crisis, the more we can contribute to reducing the effects it will have on organizations and jobs. Besides, we believe that this is a time when we, as researchers, have to contribute to society by helping in every way we can. The best way to contribute with our skills is to provide a better understanding of how, in which conditions, and to what extent the pandemic crisis will influence organizations.We provide two following sections for this editorial. First, a suggestion of research themes to be addressed, and secondly, a section regarding the cautions we must have when researching the effects of the pandemic crisis. Suggestions of research themes Impacts of the pandemic crisis over firm performance. Some works are already looking into how the pandemic crisis will impact firm performance (Aifuwa et al., 2020; Gonzalez-Uribe & Wang, 2020). This is a very important topic as the economic performance of the world will be hindered by the crisis. It is important not only to understand how the pandemic will reduce the performance of firms but also to investigate under which conditions this reduction will happen, in which industries, and depending on which firm-specific settings. Strategic responses to the pandemic crisis. Which strategies have firms put up to deal with the crisis? Which kinds of strategic moves have been successful and reduced the impact of the crisis? How could these strategies shape businesses in the near future? It is especially interesting to investigate if firms can develop capabilities through the crisis and how these capabilities willshape future strategies. Global value chains and the pandemic. As companies throughout the world will have to deal with the disruption of global value chains during the pandemic (Bonadio et al., 2020), it is important to investigate how this disruption could shape the future of global value chains. Will companies diversify their value chains to avoid future problems in similar situations? What have we learned with the challenges of finding alternatives and dealing with disruptions of the chain? Institutional pressures, adaptation, and conformity in times of pandemics. Institutions are crucial for strategic decisions and the following performance of firms. However, the institutional environment is usually perceived as the rules of the game that change in a very slow fashion (North, 1990). The challenges that the pandemic crisis imposed upon firms have greatly changed the way that business is conducted. But are institutional pressures reinforced or loosened during a crisis as the pandemic? Could the pandemic crisis spark an institutional change? Pandemic-driven stress and its effects on decision-making. Organizations already struggle to maintain acceptable levels of strategic decision-making in normal circumstances, and in situations such as the current one, this becomes even more complex, subjective, and difficult. Decision-making is the cornerstone of most schools of thought in strategy, and crises escalate choices and consequences (Oroszi, 2018). Latin American organizations are sometimes considered more vulnerable in a plethora of dimensions, and the ongoing pandemic is most likely to influence decision-making in the area negatively. Teams, coordination and multinational efforts. Crises stir trouble but also provide interesting aspects worth of studying for teams and coordination (Driskell et al., 2018). Whereas technologies may mitigate the negative effects of the pandemic on team coordination, new ways of organizing work and making group efforts and decisions may also come up. Multiple stakeholders and conflicts in decision-making. Critical times impose extreme pressures not only on teams but also on stakeholders, especially external ones. Current literature still has gaps on conflicts between ideas as competing pressures and crises tend to overemphasize and distort stakes (van der Wal, 2020). Born globals, startups, and innovation in times of crisis. What are the effects – both negative and positive – of crises on innovation? More specifically, what happens to supposedly more vulnerable beginning endeavors such as born globals (Pepelasis & Protogerou, 2018) and startups (Haase & Eberl, 2019)? What are the capabilities they have developed or are seeking in order to survive these troubling times? SME Entrepreneurship and frugal innovation. As with born globals and startups, we must look to the opposite end of the scale. How are small and medium organizations dealing with the effects of the current crisis? Are there any behavior shifts and strategic alterations that can subside such negative consequences?Countercyclical industries and fields during crises. In the Iberoamerican territories, are there any industries and fields that are gaining momentum in a countercyclical fashion? What are these and what features do they have to promote growth? Can this growth be sustainable once the crisis subsides? Agroindustrial and low-tech industries may be examples, but other fields can also shed light on the matter (Martins et al., 2019). Cautions for researching the pandemic crisis As the pandemic crisis is still undergoing as we write this editorial, we thought of providing some guidance about the special care researcher must-have when dealing with this delicate issue. These are ethical guidelines that we see as important to be followed to ensure a meaningful discussion in the academic field. Do not put a value on lives and health. It is impossible to put a value on life. As researchers of the management field, we are focused on understanding the effects of the pandemic on organizations. We have seen statements treating the crisis as a tradeoff between lives and jobs, or between health and the economy. We are not in a position of pointing a side in this situation. We advise researchers always to remember that lives are invaluable. Do not step outside of your field of research. Many scholars from several fields have conducted research trying to understand and predict the spread of the Covid-19 disease, mainly using their skills with data. This effort is remarkable; however, this is not a competence of the management field as we are not trained in understanding diseases. We, therefore, encourage researchers to look at the effects of the crisis in organizations, and we advise not to delve into understanding the disease per se as this is not our expertise. Do not guide the research question by political agendas. We understand that there are many political interests regarding the results of research on the crisis. We also understand that it is tempting to answer direct questions posed by politicians in the issue. However, we advise scholars not to directly tackle into answering politically-driven questions and to maintain the impartiality we always have. Do not twist your theory/method/argumentation to fit a crisis. As of now, we see a surge on pandemic-related research on all fields. While in some fields this is expected (such as epidemiology or economics), not all management research is closely related to the topic. Several fields have also seen a surge in pandemic-framed research that is only marginally tangential to the topic – management included. Reshaping your study to fit the crisis it does not directly relate to is not only intellectually dishonest but also takes space and time from editors and reviewers from doing their job on papers that actually can contribute to the ongoing scenario
Entropy measures reveal collective tactical behaviours in volleyball teams: how variability and regularity in game actions influence competitive rankings and match status
This study analysed and compared the influence of match status and final team rankings on variability of tactical performance behaviours within side-out phase, in female volleyball teams of different competitive levels. Performance data were analysed from matches (n = 8 for each level) in the 2012 Olympic women’s volleyball competition (elite level) and the Portuguese women’s league (national level) in the 2014–2015 season, with a total of 1496 rallies observed. Variability of setting conditions, attack zone, attack tempo and block opposition were assessed using Shannon entropy measures. Magnitude-based inferences were used to analyse and compare values of selected variables. Results showed that current match status had no influence on tactical performance of elite teams showing that they adapted their collective organisation without losing their game patterns. Analysis of final team rankings showed that, at national level, the highest ranked teams revealed greater unpredictability in all tactical performance measures (mainly in attack tempo and block opposition), emphasising the importance of the setter to differentiate performance of national teams. These findings may guide coaches in designing practice contexts for developing specific game patterns (setting conditions) and in seeking greater variability in other game actions (in attack), regardless of competitive level of performance
Síntese e caracterização da céria dopada com gadolínia e samária para aplicação em células combustíveis SOFC’s
Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Faculdade UnB Gama, Curso de Engenharia de Energia, 2016.Considerando a necessidade crescente do mundo no desenvolvimento de novas
tecnologias para produção de energia limpa, novos materiais são pesquisados para
suprir estas necessidades. Este é o caso de materiais condutores de íons oxigênio
baseados em céria dopada, que atualmente são muito atraentes por oferecer elevada
condutividade iônica (10-2 σ/cm-1) a temperaturas consideradas intermediarias (∼600
°C). Esta característica torna os materiais baseados em céria dopada promissores
para aplicações em células combustíveis de óxido sólido (SOFCs). Este trabalho de
conclusão de curso tem por objetivo principal desenvolver eletrólitos sólidos cerâmicos
para aplicações em células combustíveis. São propostas duas estequiometrias:
Ce0.8Gd0.2O2 e Ce0.8Gd0.18Sm0.02O2 a fim de estudar a influência da mono e dupla
dopagem na condutividade elétrica da céria. Os materiais de partida foram nitratos
hexaidratados com pureza de 99,95%. Como métodos de síntese para obtenção do
material cerâmico foram escolhidos o método dos precursores poliméricos (Pechini) e
a precipitação controlada, pois estes métodos garantem homogeneidade química,
obtenção de pós com tamanho de partícula da ordem dos nanômetros e
principalmente, reprodutibilidade do processo. A caracterização dos óxidos
sintetizados revelou a formação de solução sólida substitucional na céria, pois na
difração de raios X não foi identificada a formação de segundas fases. Corpos de
prova foram conformados via prensagem uniaxial a frio (249 MPa) e posteriormente
sinterizados à temperatura de 1500 °C por duas horas. Após caracterização dos
compactados foi constatada a maior densidade aparente, 91%, na amostra de
Ce0.8Gd0.18Sm0.02O2 obtida pelo método Pechini. A amostra Ce0.8Gd0.2O2, obtida pelo
mesmo método, obteve uma densidade aparente de 87%. A espectroscopia de
impedância revelou que a condutividade iônica destas amostras na temperatura de
600 °C foi de 1.5x10-2 σ/cm-1 e de 0.4x10-2 σ/cm-1 respectivamente. Estes resultados
sugerem que a incorporação de um segundo dopante influência de forma benéfica a
sinterabilidade e a condutividade da céria.Considering the growing necessity in the world for developing new clean energy
technologies, research is done to create new materials that can supply the demand for
those necessities. That is the case of the new materials used as oxygen ions
conductors based in doped ceria. Nowadays they are attractive since they offer high
ionic conductivity (10-2 σ/cm-1) in temperature considered intermediaries (~600ºC).
This characteristic makes those materials based in doped ceria, a candidate for
application in solid oxide fuels cells (SOFCs). The goal of this final project is develop
solid ceramics electrolytes to be applied in fuel cells. Two stoichiometries are proposed
in order to study the influence of the mono and double doping in the electrical
conductivity of the ceria: Ce0.8Gd0.2O2 and Ce0.8Gd0.18Sm0.02O2. The materials
of the first were hexahydrate nitrates with a purity of 99.95%. As far as synthesis
methods to obtain the ceramic materials, the Pechini method and the controlled
precipitation method were chosen. This is because those methods allow for chemical
homogeneity, powders with grain sizes in nanometer orders and mainly, the capacity
to reproduce the work. The characterization of the synthesized oxides revealed the
formation of a substitutional solid solution in the ceria, because the XRD was not
identified any second phase formations. Samples were conformed by cold uniaxial
pressing (187 MPa) and after that sintered at 1500ºC for two hours. After the
characterization of the compacted samples, a higher bulk density was found (91%) in
the Ce0.8Gd0.18Sm0.02O2 sample synthesized by Pechini’s method. The sample
Ce0.8Gd0.2O2 obtained by the same method, had a bulk density of 87%. The
impedance spectroscopy revealed that the ionic conductivity of those samples at
600ºC were 1.5x10-2 σ/cm-1 e de 0.4x10-2σ/cm-1 respectively. These results suggest
that the incorporation of a second dopant will positively influence the sinterability and
the ceria’s conductivity, which may be potentially beneficial technology in the field of
clean energy
Black coated tongue in integrative medicine: An alarm signal
Univ Fed Sao Paulo, Dept Neurol, Div Neuromuscular Dis Invest, Sao Paulo, SP, BrazilUniv Fed Sao Paulo Unifesp, Sao Paulo, SP, BrazilDivision of Neuromuscular Disease Investigation, Department of Neurology, Universidade Federal de São Paulo, São Paulo, SP, BrazilWeb of Scienc
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