220 research outputs found
REFLEXÕES (ainda) NECESSÁRIAS ACERCA da MOBILIDADE ESTUDANTIL
O processo de internacionalização da educação superior e a mobilidade dos estudantes têm sido alvos de discussão tanto no meio acadêmico quanto empresarial. Nos últimos anos, porém, percebe-se alguma supremacia nos discursos em favor da visão que privilegia a esfera mercantil, dando-lhe contornos mercadológicos. A reflexão proposta retoma a postura dialética sobre a questão, descortinando as contradições próprias do processo e do discurso. A metodologia adotada concentra-se em pesquisa documental e bibliográfica, por meio da consulta a sítios especializados e acesso a resultados de pesquisas desenvolvidas pelo Banco Mundial (BIRD), Organização das Nações Unidas para a Educação, Ciência e a Cultura (UNESCO), e Instituto Internacional para a Educação Superior na América Latina e no Caribe (IESALC) ou com respectivas chancela. Na conclusão, a perspectiva crítica em relação ao fenômeno da mobilidade estudantil é reforçada. Dessa forma, o texto oferece alguns subsídios teóricos para a comunidade acadêmica questionar posturas que se querem hegemônicas, com alguma perspectiva de recuperar o potencial emancipatório presente na mobilidade estudantil
Factorial design for collagenase production by Penicillium sp. selected from the Caatinga soil
Collagenolytic proteases can hydrolyze both denatured and native collagen and are becoming
increasingly important commercially. The aim of this work was to select a new strain of Penicillium
sp. isolated from the soil of Caatinga for collagenase production. A factorial design 24 was
performed to determine the best conditions of enzyme production. Collagenolytic activity reported
on this work is about 2 times larger than existing data. According to the growth kinetics, after 126
hours of production, were obtained the highest values of collagenolytic activity and specific activity.
The highest values of collagenolytic activity and specific activity were obtained on a culture medium
containing 0.25% (w/v) gelatin, 200 rpm, pH 8.0 and 24 °C. Only two factors were statistically
significant: pH and temperature, both with negative effects. The experimental design made possible
to define fermentation culture conditions able to increase by 66% the value of the initial enzyme
activity.Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco
(FACEPE) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Purification and characterization of a collagenase from Penicillium sp. UCP 1286 by polyethylene glycol-phosphate aqueous two-phase system
Collagenases are proteolytic enzymes capable of degrading both native and denatured collagen, reported to be applied in industrial, medical and biotechnological sectors. Liquid-liquid extraction using aqueous two-phase system (ATPS) is one of the most promising bioseparation techniques, which can substitute difficult solid-liquid separation processes, offering many advantages over conventional methods including low-processing time, low-cost material and low-energy consumption. The collagenase produced by Penicillium sp. UCP 1286 showed a stronger affinity for the bottom salt-rich phase, where the highest levels of collagenolytic activity were observed at the center point runs, using 15.0% (w/w) PEG 3350 g/mol and 12.5% (w/w) phosphate salt at pH 7.0 and concentration. The enzyme was characterized by thermal stability, pH tolerance and effect of inhibitors, showing optimal collagenolytic activity at 37 °C and pH 9.0 and proved to be a serine protease. ATPS showed high efficiency in the collagenase purification, confirmed by a single band in SDS/PAGE, and can in fact be applied as a quick and inexpensive alternative method.This work was supported by the National Council of Technological and Scientific Development (CNPq) and Coordination for the Improvement of Higher Education Personnel (CAPES). Sara Silvério also acknowledges her post-doc grant (SFRH/BPD/88584/2012) from FCT (SFRH/BPD/88584/2012) (Portuguese Science and Technology Foundation), Portugal
Production and characterization of collagenase by Penicillium sp. UCP 1286 isolated from Caatinga soil
A new Penicillium sp. strain isolated from the soil of Caatinga, a Brazilian Biome (UCP 1286) was selected for collagenase production. Fermentation system allowing obtention of collagenolytic activity about 2.7 times higher than existing data, with the highest values of collagenolytic and specific activity (379.80 U/mL, 1460.77 U/mg, respectively), after 126 hours. Applying a factorial design, enzyme production was increased by about 65% compared to the preliminary results. The factorial design demonstrated the existence of two factors with statistical significance on the production of the enzyme: pH and temperature, both with negative effects. Enzyme was found to be more active at pH 9.0 and 37 °C, and also to be very stable in comparison with the collagenase produced by other microorganisms. The enzyme seems to belong to collagenolytic serine proteases family. Concerning the substrate specificity, it was observed that the highest enzyme activity corresponds to azocoll, there was no relevant activity on azocasein and the enzyme showed to be more specific to type V collagen and gelatin than the commercial colagenase produced by Clostridium histolyticum. Major band observed at electrophoresis was approximately 37 kDa. Zymogram analysis confirmed the collagenolytic activity. All data indicates this enzyme as promising biotechnology product.This work was supported by Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE) (IBPG-0137-2.08/12) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Sara Silvério also acknowledges her post-doc grant (SFRH/BPD/88584/2012) from FCT (Fundação para a Ciência e a Tecnologia), Portugal
Cerebellar Transcranial Direct Current Stimulation Applied over Multiple Days Does Not Enhance Motor Learning of a Complex Overhand Throwing Task in Young Adults
Cerebellar transcranial direct current stimulation (tDCS) enhances motor skill and learning in relatively simple motor tasks, but it is unclear if c-tDCS can improve motor performance in complex motor tasks. The purpose of this study was to determine the influence of c-tDCS applied over multiple days on motor learning in a complex overhand throwing task. In a double-blind, randomized, between-subjects, SHAM-controlled, experimental design, 30 young adults were assigned to either a c-tDCS or a SHAM group. Participants completed three identical experiments on consecutive days that involved overhand throwing in a pre-test block, five practice blocks with concurrent c-tDCS, and a post-test block. Overhand throwing endpoint accuracy was quantified as the endpoint error. The first dorsal interosseous muscle motor evoked potential (MEP) amplitude elicited by transcranial magnetic stimulation was used to quantify primary motor cortex (M1) excitability modulations via c-tDCS. Endpoint error significantly decreased over the 3 days of practice, but the magnitude of decrease was not significantly different between the c-tDCS and SHAM group. Similarly, MEP amplitude slightly increased from the pre-tests to the post-tests, but these increases did not differ between groups. These results indicate that multi-day c-tDCS does not improve motor learning in an overhand throwing task or increase M1 excitability
Transcranial direct current stimulation of primary motor cortex over multiple days improves motor learning of a complex overhand throwing task
Transcranial direct current stimulation (tDCS) applied to the primary motor cortex (M1) improves motor learning in relatively simple motor tasks performed with the hand and arm. However, it is unknown if tDCS can improve motor learning in complex motor tasks involving whole-body coordination with significant endpoint accuracy requirements. The primary purpose was to determine the influence of tDCS on motor learning over multiple days in a complex over-hand throwing task. This study utilized a double-blind, randomized, SHAM-controlled, between-subjects experimental design. Forty-six young adults were allocated to either a tDCS group or a SHAM group and completed three experimental sessions on three consecutive days at the same time of day. Each experimental session was identical and consisted of overhand throwing trials to a target in a pre-test block, five practice blocks performed simultaneously with 20 min of tDCS, and a post-test block. Overhand throwing performance was quantified as the endpoint error. Transcranial magnetic stimulation was used to obtain motor-evoked potentials (MEPs) from the first dorsal interosseus muscle to quantify changes in M1 excitability due to tDCS. Endpoint error significantly decreased over the three days of practice in the tDCS group but not in the SHAM group. MEP amplitude significantly increased in the tDCS group, but the MEP increases were not associated with increases in motor learning. These findings indicate that tDCS applied over multiple days can improve motor learning in a complex motor tasks in healthy young adults
GRAMÁTICA DA PAQUERA ONTEM E HOJE EM GURUPI (TO)
The discussion about the grammars of relationships and regimes of desire are transversal themes to the debates of and in contemporary society. In this article, we seek to discuss what is in common and the possible changes in the demonstrations of affective-love-sexual interest among young people, in two distinct moments (1999 and 2019), in the municipality of Gurupi, specifically narrated in two media, namely: section Recadinhos of the local newspaper Cocktail and Instagram profile Crush Gurupi. For this, we avail ourselves of the methodological assumptions of Motta's Critical Analysis of Narrative (2013). We understand that there is the existence of relationship models and desire regime 'romantic love' and 'neoliberal love'/liquid love, which are presented through narratives with tacit lexicons of each era.La discusión sobre las gramáticas de las relaciones y los regímenes del deseo son temas transversales a los debates de y en la sociedad contemporánea. En este artículo, buscamos discutir lo que hay en común y los posibles cambios en las manifestaciones de interés afectivo-amoroso-sexual entre los jóvenes, en dos momentos distintos (1999 y 2019), en el municipio de Gurupi, específicamente narrados en dos soportes, a saber: sección Recadinhos del periódico local Cocktail y perfil en Instagram Crush Gurupi. Para ello, hacemos uso de los supuestos metodológicos del Análisis Crítico de la Narrativa de Motta (2013). Entendemos que existe la existencia de modelos de relación y régimen de deseo 'amor romántico' y 'amor neoliberal'/líquido, que se presentan a través de narrativas con léxicos tácitos de cada época.A discussão sobre as gramaticas de relacionamentos e regimes de desejo são temas transversais à debates da e na sociedade contemporânea. Neste artigo, buscamos discutir o que há em comum e as possíveis mudanças nas demonstrações de interesse afetivo-amoroso-sexual entre pessoas jovens, em dois momentos distintos (1999 e 2019), no município de Gurupi, especificamente narrado em dois suportes, a saber: secção Recadinhos do jornal local Cocktail e perfil no Instagram Crush Gurupi. Para tanto, valemo-nos dos pressupostos metodológicos da Análise Crítica da Narrativa de Motta (2013). Compreendemos que há a existência de modelos de relacionamento e regime de desejos ‘amor romântico’ e ‘amor neoliberal’/líquido, os quais são apresentados por meio de narrativas com léxicos tácitos de cada época
Phytoconstituents from Sidastrum micranthum (A. St.-Hil.) Fryxell (Malvaceae) and antimicrobial activity of pheophytin a
Sidastrum micranthum (A. St.-Hil.) Fryxell, a member of the Malvaceae family, is called malva preta in Brazil. As this species is commonly used to treat bronchitis, cough, and asthma, better knowledge of its chemical compounds is important. The phytochemical study of its hexane extract, using chromatographic techniques, led to isolation of six compounds: the triterpene isoarborinol, a mixture of sitosterol and stigmasterol, sitosterol-3-O-β-D-glucopyranoside, pheophytin a, and 132-hydroxy-(132-S)-pheophytin a. Structural identification of these compounds was carried out using spectroscopic methods such as IR and 1D and 2D NMR (HOMOCOSY, HMQC, HMBC, and NOESY). Compounds isolated from S. micranthum were screened for their in vitro antifungal and antibacterial activity against twenty fungal and bacterial standard strains. Pheophytin a exhibited antimicrobial action against all microorganisms tested.Sidastrum micranthum (A. St.-Hil.) Fryxell, pertencente à família Malvaceae, é conhecida no Brasil como "malva preta". A espécie é popularmente usada contra bronquite, tosse e asma, mostrando a relevância de conhecer melhor sua composição química. O estudo fitoquímico do extrato hexânico da espécie, utilizando técnicas cromatográficas, conduziu ao isolamento de seis compostos: o triterpeno isoarborinol, mistura de sitosterol e estigmasterol, sitosterol-3-O-β-D-glicopiranosídeo, feofitina a e de 132-hidroxi-(132-S)-feofitina a. A identificação estrutural destes compostos foi realizada com base em métodos espectroscópicos, tais como IV, RMN 1D e 2D (HOMOCOSY, HMQC, HMBC e NOESY). As substâncias isoladas de Sidastrum micranthum foram avaliadas quanto às suas atividades antimicrobianas in vitro, contra vinte cepas fúngicas e bacterianas. A feofitina a mostrou ação antimicrobiana contra todos os microrganismos testados
Modelos para volume comercial do fuste com e sem casca de eucalipto citriodora
O eucalipto citriodora (Corymbia citriodora (Hook.) K.D.Hill & L.A.S. Johnson), apesar de ter um potencial de investimentos em plantios comerciais no Brasil, é pouco estudado, principalmente, quanto à estimativa do volume de árvores individuais. Diante do exposto, objetivou-se com o presente trabalho avaliar alguns modelos volumétricos de dupla entrada, a fim de estimar o volume de madeira do fuste comercial com e sem casca de árvores individuais de eucalipto citriodora. Para isso, inicialmente, foram avaliados 18 modelos de dupla entrada por meio de critérios estatísticos, como erro padrão residual, coeficiente de determinação ajustado e análise gráfica da distribuição dos resíduos. Nesta oportunidade, utilizando o modelo que mais se destacou, fez-se o seu ajuste para gerar uma única equação volumétrica, tanto para volume com casca, como para sem casca. Neste caso, incluiu-se neste ajuste, a variável binária Tx = 0 para volume com casca e Tx = 1 para volume sem casca. Na avaliação das estimativas com e sem casca empregou-se a média dos erros absolutos, raiz quadrada do erro médio e soma dos quadrados dos resíduos relativos. Concluiu-se pelo uso de um modelo volumétrico com melhor desempenho que o de Schumacher e Hall e que, este modelo selecionado, ao ser adaptado ao uso da variável binária Tx, gerou uma única equação para estimar volume com e sem casca tendo um comportamento similar ao emprego da forma usual, onde são geradas duas equações volumétricas em separado para volume com e sem casca
Práticas de RSAE em usinas de cana-de-açúcar: caso de uma região tradicionalmente produtora
O presente estudo foi desenvolvido visando identificar a gestão práticada nas usinas de cana-de-açúcar e relacionando-as ao conceito de Responsabilidade Socioambiental Empresarial (RSAE). Utilizou-se como base teórica o tripé da sustentabilidade, Triple Bottom Line, que se funda no estudo dos aspectos econômicos, sociais e ambientais. Pesquisa de natureza descritiva do tipo quali-quantitativa. Adotado como metodologia de abordagem o estudo de casos múltiplos realizado em um universo de treze usinas em operação na região escolhida (PE). Para coleta de dados utilizou-se entrevistas semi-diretivas e questionários em escala Likert, envolvendo gestores das usinas, dirigentes de sindicatos, associações e agentes de órgãos de fiscalização ambiental. Foram utilizadas para interpretação dos dados, técnicas de análise de conteúdo, estatística descritiva (teste de hipóteses) e análise multivariada de dados (análise de cluster). Observou-se que a gestão praticada pelas usinas converge para a existência de dois grupos: um formado por empresas que desempenham com responsabilidade socioambiental e outro formado por usinas menos adeptas às práticas sustentáveis. A constatação que se pode extrair permite concluir que a RSAE até existe na prática das usinas do setor, mas não advém da expectativa em obter vantagem competitiva e sim, como estratégia de sobrevivência
- …