1,097 research outputs found
Effect of plain and carboxylated styrene-butadiene rubber on the rheological behavior of silica fume-class G Portland cement slurries
The incorpation of a high pozzolan content in cement systems enables an enhanced thermal stability. In an even harsh condition, where imposed deformations occur in addition to high temperatures, it is desirable that cementitious systems present high ductility, which can be achieved for example by adding polymers. The aim of this paper, is to better understand the rheological behavior of ductile cement slurries, designed for oil wells subjected to cyclic steam stimulation. The studied cement formulations contain Silica Fume and two different copolymers (Styrene-Butadiene and its carboxylated version). The influence of each copolymer content on the rheological parameters was investigated. Isothermal calorimetry was used to measure the induction period to guarantee that rheological parameters were carried out in the same hydration period. As the rheometer test was carried out in a non-isothermal condition together with a vane applied shear rate, increased reaction rates are expected. However, it is plausible to assume that the pastes remained in the induction period otherwise they would be in the acceleratory period where pastes start to set. Attempts have been made to correlate properties found by rheometry in the mini-slump test. It was observed that the XSBR delays and decreases the ettringite formation in the first hours of cement hydration, leading to lower yield stress values and increased viscosity and thixotropy. Good correlations were established between parameters measured by rheometry and mini-slump tests, which show promising results for potential use in on-site yield stress and plastic viscosity tests in Oil Well applications
PARAYSYRY: DESENVOLVIMENTO DE UM JOGO MOBILE SOBRE EDUCA??O AMBIENTAL
O projeto prop?e o desenvolvimento de um jogo infantil para smartphones sobre educa??o
ambiental utilizando o m?todo de game design ?Regra do Ciclo?, de Jesse Schell. Diante de
pesquisas relacionando jogos e educa??o, al?m da problem?tica da polui??o do meio ambiente,
procurou-se construir um prot?tipo digital para o sistema Android com foco no projeto gr?fico,
e com conte?do ambiental elaborado em consulta com especialistas da ?rea. O resultado foi um
modelo funcional com um n?vel, do g?nero aventura, que contextualiza a quest?o da
preserva??o da ?gua
Letramento liter?rio e bibliotecas escolares : uma pesquisa explorat?ria no munic?pio de Ouro Preto.
Programa de P?s-Gradua??o em Educa??o. Departamento de Educa??o, Instituto de Ci?ncias Humanas e Sociais, Universidade Federal de Ouro Preto.Esta pesquisa teve como objetivo investigar o uso das bibliotecas escolares para o letramento liter?rio de alunos de Ensino Fundamental da Rede Municipal de Ouro Preto. Para isso, realizamos um estudo em duas escolas de Ensino Fundamental. Participaram da pesquisa oito professoras, sendo seis professoras regentes e duas em readapta??o funcional, respons?veis pelas bibliotecas dessas escolas. Os dados coletados foram obtidos a partir de entrevistas semiestruturadas realizadas com as docentes, documentos e observa??es pontuais do ambiente escolar. O embasamento te?rico-metodol?gico da pesquisa est? alicer?ado em trabalhos como os de Soares (1998), Paulino (2001), Cosson (2006), Souza (2009) e Corr?a (2016). Dentre os principais resultados encontrados destacam-se: 1) Constata??o de que apenas 37% das escolas da Rede Municipal de Ouro Preto que atendem ao Ensino Fundamental possuem bibliotecas e de que inexiste uma pol?tica de bibliotecas ou de leitura no munic?pio. 2) Exist?ncia de uma nova concep??o de biblioteca entre as professoras investigadas, pensada como um lugar de intera??o, movimento, divulga??o de informa??es, cultura, lazer, entretenimento, inven??o e circula??o da informa??o. 3) Identifica??o de tr?s tipos gerais de pr?ticas de letramento liter?rio empregadas pelas professoras em sala de aula: a) pr?ticas de letramento liter?rio com intuito de alfabetizar (fins utilitaristas e pedag?gicos); b) pr?ticas de letramento liter?rio abordando quest?es ligadas a temas transversais (fins morais); c) pr?ticas de letramento liter?rio com a inten??o do deleite e da frui??o.4) Nas duas escolas investigadas as bibliotecas, mesmo com as devidas limita??es, t?m funcionado como espa?os destinados ? realiza??o de atividades de letramento liter?rio e de est?mulo ? leitura. Ficou evidenciado que as bibliotecas s?o locais valorizados pelos docentes e nos quais as crian?as gostam de estar. Os principais usos da biblioteca para o letramento liter?rio foram: a) hor?rios espec?ficos para o desenvolvimento de atividades para garantir que as crian?as frequentem a biblioteca e para que as professoras desenvolvam pr?ticas de letramento liter?rio. b) Realiza??o de eventos culturais envolvendo a leitura e leitura liter?ria com forte participa??o das fam?lias. Por fim, espera-se que os resultados deste estudo tenham contribu?do para evidenciar que ? preciso e urgente inserir a biblioteca escolar na pauta das discuss?es sobre a melhoria do ensino e a forma??o de leitores em Ouro Preto e no Brasil.This research aimed to investigate the usage of school libraries to the literary literacy of students at Ouro Preto Municipal Primary School. Thus, a study was conducted at two primary schools. Eight teachers, six regents and two in functional realignment, in charge of the libraries of these schools, participated of this research. The data collected was obtained from semi-structured interviews with the docents, documents and punctual observation of the school environment. The theoretical and methodological framework for this study was built from works such as those of Soares (1998), Paulino (2001), Cosson (2016), Souza (2009) and Corr?a (2017). Among the main results found, there can be highlighted: 1) The confirmation that only 37% of Ouro Preto Municipal Schools of Primary Education have libraries and that there is not a library or reading policy in the city. 2) The existence of a new conception of library between the investigated teachers, thought as a place of interaction, dynamics, and information sharing, culture, leisure, invention and information flow. 3) Identification of three kinds of literary literacy practice applied by the teachers in class: a) literary literacy practices in order to alphabetize (utilitarian and pedagogical purposes); b) literary literacy practices regarding questions about transversal themes (moral purposes); c) literary literacy practices to achieve enjoyment and fruition. 4) Both of the investigated schools libraries, even with their limitations, have functioned as a space where literary literacy activities and encouragement of reading take place. It was evidenced that the libraries are places which are valued by the teachers and in where children like to be. The main usages of the library for the literary literacy were: a) specific schedules for the development of activities to guarantee that children would frequent the library and for the teachers to conduct practices of literary literacy. b) Accomplishment of cultural events regarding reading and literary reading with a strong participation of the families. Lastly, it is expected that the results of this study help to contribute to evidence that it is required and urgent to insert the school library in the discussions about education improvement and readers formation in Ouro Preto and in Brazil
Efeitos de um protocolo de treinamento de subida em escada sobre vari?veis relacionadas ? resist?ncia ? insulina em camundongos alimentados com dieta hiperlip?dica
O presente trabalho foi realizado com apoio da Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - Brasil (CAPES) - C?digo de Financiamento 001.O treinamento f?sico ? um importante m?todo terap?utico n?o farmacol?gico para
o tratamento e preven??o de diversas doen?as como a obesidade, a resist?ncia ? insulina
e o diabetes mellitus tipo 2. O treinamento de subida em escadas para roedores pode ser
uma estrat?gia para estudar os efeitos do treinamento no metabolismo da glicose.
Anteriormente, nosso grupo de pesquisa observou que o treinamento de subida em escada
foi capaz de melhorar a toler?ncia ? glicose e reduzir a adiposidade em camundongos
alimentados com dieta hiperlip?dica. No presente estudo utilizamos amostras
provenientes daquele estudo para analisarmos a resist?ncia ? insulina, a fun??o
mitocondrial no tecido muscular e adiposo, e prote?nas envolvidas com a resist?ncia ?
insulina no tecido muscular esquel?tico. Quarenta e oito animais foram divididos em 2
grupos (n=24) sendo grupo chow alimentado com ra??o comercial (10% das calorias de
gordura) e grupo HFD (de high fat diet) alimentado com dieta hiperlip?dica (42% das
calorias de gordura) por 12 semanas. Na quinta semana todos os animais foram adaptados
para a subida em escada e passaram por testes f?sicos para determina??o da carga utilizada
no treinamento. Os grupos foram subdivididos em grupos sedent?rios e grupos treinados
(n=12/grupo). Na sexta semana experimental se deu o in?cio do protocolo de treinamento
de forma progressiva que durou por 6 semanas. O treinamento de for?a de subida em
escada melhorou a resist?ncia ? insulina e aumentou o conte?do e fosforila??o de
prote?nas relacionadas ao metabolismo de glicose que estavam alterados no animais
sedent?rios alimentados com dieta hiperlip?dica. O presente estudo mostrou que o
treinamento de for?a de subida em escada foi capaz de melhorar a resist?ncia ? insulina,
provavelmente por modular prote?nas intracelulares relacionadas ? via de sinaliza??o da
insulina.Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Disserta??o (Mestrado) ? Programa Multic?ntrico de P?s-gradua??o em Ci?ncias Fisiol?gicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2020.Physical training is an important non-pharmacological therapeutic method for
the treatment and prevention of diseases such as obesity, insulin resistance and type 2
diabetes mellitus. Rodent ladder training can be a strategy to study the effects of training
without glucose metabolism. Previously, our research group noted that stair climbing
training was able to improve glucose tolerance and reduce adiposity in mice fed a high-fat
diet. In the present study, we used data from that study to analyze insulin resistance,
mitochondrial function in muscle and adipose tissue, the proteins involved with insulin
resistance in skeletal muscle tissue. Forty-eight animals were divided into 2 groups (n =
24) with a chow group fed commercial feed (10% of the fat calories) and an HFD group
(on a high fat diet) fed with a high fat diet (42% of the fat calories) by 12 weeks. In the
fifth week, all animals were adapted to climb stairs and underwent physical tests to
determine the load used in training. The groups were subdivided into sedentary groups
and trained groups (n = 12 / group). In the sixth experimental week, the training protocol
started progressively, which lasted for 6 weeks. Stair climbing strength training improved
insulin resistance and increased protein content and phosphorylation related to glucose
metabolism that was altered in sedentary animals fed a high-fat diet. The present study
showed that stair climbing strength training was able to improve insulin resistance,
probably due to modular intracellular proteins related to the insulin signaling pathway
Narrowing Perceptual Sensitivity to the Native Language in Infancy: Exogenous Influences on Developmental Timing
The infancy literature situates the perceptual narrowing of speech sounds at around 10 months of age, but little is known about the mechanisms that influence individual differences in this developmental milestone. We hypothesized that such differences might in part be explained by characteristics of mother-child interaction. Infant sensitivity to syllables from their native tongue was compared longitudinally to sensitivity to non-native phonemes, at 6 months and again at 10 months. We replicated previous findings that at the group level, both 6- and 10- month-olds were able to discriminate contrasts in their native language, but only 6-month-olds succeeded in discriminating contrasts in the non-native language. However, when discrimination was assessed for separate groups on the basis of mother-child interaction—a ‘high contingency group’ and a ‘moderate contingency’ group—the vast majority of infants in both groups showed the expected developmental pattern by 10 months, but only infants in the ‘high contingency’ group showed early specialization for their native phonemes by failing to discriminate non-native contrasts at 6-months. The findings suggest that the quality of mother-child interaction is one of the exogenous factors influencing the timing of infant specialization for speech processing
Descomposición de datos multi-espectrales: interfaz gráfica para Matlab
Avances recientes han permitido el desarrollo de dispositivos capaces de capturar información en múltiples longitudes de onda. Estos datos tienen diversas aplicaciones con el problema en común de cómo interpretarlos. Una de las técnicas utilizadas con este fin es la descomposición espectral, que separa los datos de una muestra en sus componentes básicos y concentraciones proporcionales. Nuestro trabajo previo ha estado enfocado en la descomposición espectral de datos de fluorescencia multiespectral, donde se han desarrollado métodos que proporcionan una solución cuantitativa, robusta y rápida, la cual no está limitada por el número de componentes que se pueden caracterizar. En este trabajo, presentamos una interface desarrollada en Matlab que puede estimar los perfiles característicos de los componentes constituyentes de una muestra y sus abundancias. En caso de que no se tenga información alguna sobre la muestra, nos permite obtener además el número de componentes en ella. El artículo hace una descripción del software y sus herramientas.Además, se ejemplifica su uso en la caracterización de muestras ex-vivo de arterias coronarias. El programa se encuentra disponible de manera gratuita y provee al usuario de una herramienta fácil de usar para el análisis de datos multi o hiper-espectrales.Palabra(s) Clave(s): descomposición ciega, fluorescencia endógena, interfaz gráfica, optimización cuadrática, quimiometría
Relation of gallbladder function and Helicobacter pylori infection to gastric mucosa inflammation in patients with symptomatic cholecystolithiasis
Background. Inflammatory alterations of the gastric mucosa are commonly caused by Helicobacter pylori (Hp) infection in patients with symptomatic gallstone disease. However, the additional pathogenetic role of an impaired gallbladder function leading to an increased alkaline duodenogastric reflux is controversially discussed. Aim:To investigate the relation of gallbladder function and Hp infection to gastric mucosa inflammation in patients with symptomatic gallstones prior to cholecystectomy. Patients: Seventy-three patients with symptomatic gallstones were studied by endoscopy and Hp testing. Methods: Gastritis classification was performed according to the updated Sydney System and gallbladder function was determined by total lipid concentration of gallbladder bile collected during mainly laparoscopic cholecystectomy. Results: Fifteen patients revealed no, 39 patients mild, and 19 moderate to marked gastritis. No significant differences for bile salts, phospholipids, cholesterol, or total lipids in gallbladder bile were found between these three groups of patients. However, while only 1 out of 54 (< 2%) patients with mild or no gastritis was found histologically positive for Hp, this infection could be detected in 14 (74%) out of 19 patients with moderate to marked gastritis. Conclusion: Moderate to marked gastric mucosa inflammation in gallstone patients is mainly caused by Hp infection, whereas gallbladder function is not related to the degree of gastritis. Thus, an increased alkaline duodenogastric reflux in gallstone patients seems to be of limited pathophysiological relevance. Copyright (c) 2006 S. Karger AG, Basel
Modeling relationships between calving traits: a comparison between standard and recursive mixed models
<p>Abstract</p> <p>Background</p> <p>The use of structural equation models for the analysis of recursive and simultaneous relationships between phenotypes has become more popular recently. The aim of this paper is to illustrate how these models can be applied in animal breeding to achieve parameterizations of different levels of complexity and, more specifically, to model phenotypic recursion between three calving traits: gestation length (GL), calving difficulty (CD) and stillbirth (SB). All recursive models considered here postulate heterogeneous recursive relationships between GL and liabilities to CD and SB, and between liability to CD and liability to SB, depending on categories of GL phenotype.</p> <p>Methods</p> <p>Four models were compared in terms of goodness of fit and predictive ability: 1) standard mixed model (SMM), a model with unstructured (co)variance matrices; 2) recursive mixed model 1 (RMM1), assuming that residual correlations are due to the recursive relationships between phenotypes; 3) RMM2, assuming that correlations between residuals and contemporary groups are due to recursive relationships between phenotypes; and 4) RMM3, postulating that the correlations between genetic effects, contemporary groups and residuals are due to recursive relationships between phenotypes.</p> <p>Results</p> <p>For all the RMM considered, the estimates of the structural coefficients were similar. Results revealed a nonlinear relationship between GL and the liabilities both to CD and to SB, and a linear relationship between the liabilities to CD and SB.</p> <p>Differences in terms of goodness of fit and predictive ability of the models considered were negligible, suggesting that RMM3 is plausible.</p> <p>Conclusions</p> <p>The applications examined in this study suggest the plausibility of a nonlinear recursive effect from GL onto CD and SB. Also, the fact that the most restrictive model RMM3, which assumes that the only cause of correlation is phenotypic recursion, performs as well as the others indicates that the phenotypic recursion may be an important cause of the observed patterns of genetic and environmental correlations.</p
Disruption of CTCF-YY1-dependent looping of the human papillomavirus genome activates differentiation-induced viral oncogene transcription.
The complex life cycle of oncogenic human papillomavirus (HPV) initiates in undifferentiated basal epithelial keratinocytes where expression of the E6 and E7 oncogenes is restricted. Upon epithelial differentiation, E6/E7 transcription is increased through unknown mechanisms to drive cellular proliferation required to support virus replication. We report that the chromatin-organising CCCTC-binding factor (CTCF) promotes the formation of a chromatin loop in the HPV genome that epigenetically represses viral enhancer activity controlling E6/E7 expression. CTCF-dependent looping is dependent on the expression of the CTCF-associated Yin Yang 1 (YY1) transcription factor and polycomb repressor complex (PRC) recruitment, resulting in trimethylation of histone H3 at lysine 27. We show that viral oncogene up-regulation during cellular differentiation results from YY1 down-regulation, disruption of viral genome looping, and a loss of epigenetic repression of viral enhancer activity. Our data therefore reveal a key role for CTCF-YY1-dependent looping in the HPV life cycle and identify a regulatory mechanism that could be disrupted in HPV carcinogenesis
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