Artigo: um olhar sobre o conhecimento matemático Kaingang

Este artigo é fruto de uma pesquisa que busca conhecer a matemática utilizada pelos indígenas Kaingang da região central do Paraná-Brasil. Esses métodos e técnicas matemáticas, segundo a concepção de D’Ambrósio, é chamada de Etnomatemática. O conhecimento da Etnomatemática do grupo pode auxiliar os membros dessa comunidade no aprendizado da matemática institucionalizada e levar a novos conceitos e conhecimentos úteis para a Educação Matemática, bem como contribuir para uma consciência coletiva a respeito da importância desse povo. Utilizou-se recursos da História Oral para a coleta de dados. A entrevista foi realizada com um indígena Kaingang e com uma pedagoga que trabalha com crianças Kaingang. Como resultado obteve-se algumas informações, que através do olhar da matemática institucionalizada nos conduz aos conteúdos relacionados a números, formas e medidas e lógica. Para este artigo destacam-se o uso de um sistema de numeração de base cinco, o método para construção de retas baseados na propagação do som e indicios de uma lógica distinta da convencional. Com isso pressupõe-se a existência de uma matemática própria do povo Kaingang e sua importância, o que instiga a continuar a busca por mais elementos da Etnomatemática desse povo

Towards a reappraisal of the phenotype of the cell wall deficient fz;sg;os-1 ( slime ) triple mutant of Neurospora crassa

Morphological mutants represent roughly 23% of seven hundred-odd distinct chromosomal loci of N. crassa, as listed by Perkins et al. (1982, Microbiol. Rev. 46:426). Probably the most radical phenotype among these strains is that of the fz;sg;os-1 ( slime ) triple mutant, which was isolated by Sterling Emerson (1963, Genetica 34:162) in a mutagenic experiment using an os-1 strain. The slime strain has been systematically referred to in the literature as a strain lacking cell wall and growing as protoplasts or plasmodium (Perkins et al. 1982). Through the years, the fragile slime structures were frequently used as a source of organelles (Martinoia et al. 1979. Arch. Microbiol. 120:31), membranes (Scarborough, 1975. J. Biol. Chem. 250:1106) or for the study of membrane-bound enzymes (Brooks et al. 1983. J. Biol. Chem. 258:13909). Slime spheroplasts practically never revert to hyphal morphology; thus, the causes for impaired cell wall synthesis were investigated and attributed either to the lack of glucan synthase activity (Leal-Morales and Ruiz-Herrera, 1985. Exp. Mycol 9:28) or to improper ultrastructural characteristics of the organelles responsible for chitin synthesis: the chitosomes (Martinez et al. 1989. Biochem. Biophys. Acta 990:45)

Multi-step approach to add value to corncob: production of biomass-degrading enzymes, lignin and fermentable sugars

This work presents an integrated and multi-step approach for the recovery and/or application of the lignocellulosic fractions from corncob in the production of high value added compounds as xylo-oligosaccharides, enzymes, fermentable sugars, and lignin in terms of biorefinery concept. For that, liquid hot water followed by enzymatic hydrolysis were used. Liquid hot water was performed using different residence times (1050 minutes) and holding temperature (180200 °C), corresponding to severities (log(R0)) of 3.364.64. The most severe conditions showed higher xylo-oligosaccharides extraction (maximum of 93%) into the hydrolysates and higher recovery of cellulose on pretreated solids (maximum of 65%). Subsequently, hydrolysates and solids were used in the production of xylanases and cellulases, respectively, as well as, pretreated solids were also subjected to enzymatic hydrolysis for the recovery of lignin and fermentable sugars from cellulose. Maximum glucose yield (100%) was achieved for solids pretreated at log(R0) of 4.42 and 5% solid loading.Michele Michelin is a recipient of a FCT fellowship (SFRH/BPD/ 100786/2014). ThisstudywassupportedbythePortugueseFoundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-010145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. Héctor Ruiz would like to thank the financial support to the Mexican Science and Technology Council (CONACYT, Mexico) for the Basic Science Project-2015-01 (Ref. 254808) and the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (Cemie-Bio), and Cluster of Bioalcohols (Ref. 249564). We thank Dr. Nelson Lima from MUM (Micoteca da Universidade do Minho, PT) that gently provided the Trichoderma reesei fungi.info:eu-repo/semantics/publishedVersio

Discussão dos determinantes do investimento externo direto na China a partir dos anos 1990

A China tem se destacado mundialmente por seu fortecrescimento econômico, 10,3% em média no período de 1980 a 2000,e por caracterizar-se como um importante receptor de InvestimentoExterno Direto (IED), acumulando de 1979 a 2000 um total deUS 346 bilhões, configurando-se como a principal naçãoabsorvedora dessa modalidade de capital, entre os países em desenvolvimento.Os estímulos à entrada de IED se iniciaram nofinal da década de 1970, mas até o início dos anos 1990 os fluxosnão foram expressivos. Foi a partir de 1991 que a China passou aatrair IED em volumes crescentes, tanto que em 1997 atingiu US44,23 bilhões. Diante disso, este trabalho objetiva discutir algunsdos condicionantes internos que explicam o direcionamento doIED para a China a partir dos anos 1990. Constatou-se que o IEDfoi fortemente atraído para o país dada a importância de suasespecificidades locais, como o tamanho e o potencial de crescimentodo mercado consumidor e a mão-de-obra abundante, barata ecom relativa qualificação. Um outro condicionante relevante foi aestabilidade e previsibilidade das políticas macroeconômicasadotadas pelo governo chinês. Ademais, também se observou opapel do governo na condução das políticas de incentivos fiscais,de marketing e de concorrência, além da sua atuação na adoção demedidas práticas visando regulamentar e reduzir as restrições impostasa esse tipo de capital

Application of a fungal extract with laccase activity to improve the enzymatic hydrolysis of eucalyptus bark residues

This work had the financial support from the Portuguese Foundation for Science and Technology under the scope of Project EcoTech (POCI-01-0145-FEDER-032206). The authors also acknowledge RAIZ for kindly providing the residues of eucalyptus bark.info:eu-repo/semantics/publishedVersio

Rhizopus microsporus var. rhizopodiformis: a thermotolerant fungus with potential for production of thermostable amylases

The effect of several nutritional and environmental parameters on growth and amylase production from Rhizopus microsporus var. rhizopodiformis was analysed. This fungus was isolated from soil of the Brazilian “cerrado” and produced high levels of amylolytic activity at 45°C in liquid medium supplemented with starch, sugar cane bagasse, oat meal or cassava flour. Glucose in the culture medium drastically repressed the amylolytic activity. The products of hydrolysis were analysed by thin layer chromatography, and glucose was detected as the main component. The amylolytic activity hydrolysed several substrates, such as amylopectin, amylase, glycogen, pullulan, starch, and maltose. Glucose was always the main end product detected by high-pressure liquid chromatography analysis. These results indicated that the amylolytic activity studied is a glucoamylase, but there were also low levels of α-amylase. As compared to other fungi, R. microsporus var. rhizopodiformis can be considered an efficient producer of thermostable amylases, using raw residues of low cost as substrates. This information is of technological value, considering the importance of amylases for industrial hydrolysis

Nanocellulose production: exploring the enzymatic route and residues of pulp and paper industry

Increasing environmental and sustainability concerns, caused by current population growth, has promoted a raising utilization of renewable bio-resources for the production of materials and energy. Recently, nanocellulose (NC) has been receiving great attention due to its many attractive features such as non-toxic nature, biocompatibility, and biodegradability, associated with its mechanical properties and those related to its nanoscale, emerging as a promising material in many sectors, namely packaging, regenerative medicine, and electronics, among others. Nanofibers and nanocrystals, derived from cellulose sources, have been mainly produced by mechanical and chemical treatments; however, the use of cellulases to obtain NC attracted much attention due to their environmentally friendly character. This review presents an overview of general concepts in NC production. Especial emphasis is given to enzymatic hydrolysis processes using cellulases and the utilization of pulp and paper industry residues. Integrated process for the production of NC and other high-value products through enzymatic hydrolysis is also approached. Major challenges found in this context are discussed along with its properties, potential application, and future perspectives of the use of enzymatic hydrolysis as a pretreatment in the scale-up of NC production.This work was carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)- LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitiveness andInternationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Programme (Lisboa 2020)and by North Portugal Regional Operational Program (Norte 2020) under the Portugal 2020 PartnershipAgreement, through the European Regional Development Fund (ERDF) and was supported by the PortugueseFoundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 and through Project EcoTech (POCI-01-0145-FEDER-032206/FAPESP 2018/07522-6) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope ofNorte2020-Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Visualização em Geometria, aproximações entre as perspectivas de Duval e Gutiérrez: um estudo com acadêmicos de um curso de licenciatura em Matemática

Este artigo é parte de uma pesquisa de doutorado em Educação Matemática e se propõe a analisar a atividade de visualização, colaborando para a discussão da temática em cursos de licenciatura em Matemática, contribuindo para que mais alternativas que favoreçam a aprendizagem em Geometria sejam encontradas. Tem-se por objetivo investigar a atividade de visualização na resolução de uma tarefa de Geometria por acadêmicos de um curso de licenciatura em Matemática de uma Universidade ao norte do estado do Paraná, ao ingressarem no curso e ao concluírem as disciplinas de Geometria constantes na estrutura curricular do referido curso, e também identificar se os conceitos Geométricos requeridos na tarefa estão matematicamente consolidados. Trata-se uma pesquisa qualitativa, na perspectiva do paradigma interpretativo, segundo a modalidade estudo de casos múltiplos. A fundamentação teórica para análise dos dados se pauta nas ideias apresentadas por Duval e por Gutiérrez sobre a visualização em Geometria. Foi observado que os elementos e operações que compõe a visualização ocorrem, de modo geral, nos dois grupos. Porém, notou-se uma diferença -ainda que pequena- entre o desempenho dos integrantes dos grupos. Foram observadas dificuldades em relação ao conceito formal de quadrado e ao emprego de alguns dos elementos e operações que compõe a visualização pela perspectiva adotada

Assessing potential effects of a laccase extract over the enzymatichydrolysis of Eucalyptus bark residues

Lignocellulosic materials are rising as an alternative to petroleum, from which biofuels and numerous compounds may be produced. Eucalyptus barks, abundantly generated by pulp & paper mills, are a good example of such materials, being typically used for energy production. Holocellulose conversion of these materials is usually made by enzyme preparations, mainly acting on the hydrolysis of complex cellulose into monomer sugars. These materials, however, can still present a substantial amount of lignin, a well-documented enzymes barrier. This work aimed to assess how a laccases extract can influence the hydrolysis of eucalyptus bark and the best conditions for their action. Eucalyptus bark residues (EBR) were initially subjected to autohydrolysis with a severity (S0) of 3.84 [1]. The pre-treated solid was then hydrolyzed using Cellic CTec2, combined with a laccases-mediated treatment employing an extract prepared by the group of Maria de Lourdes Polizelli [2]. Potential effects of laccases were estimated through the quantification of the glucose produced over time and differences in the profile of enzymes adsorption onto the solid. The effects of laccases over the hydrolysis of EBR seemed to be dependent of numerous factors. For a solids load of 2 %, laccases addition simultaneously with cellulases had no positive effects but when added 24 h before cellulases, glucose production increased 11 %, possibly from an inferior electron donors competition with LPMOs on Cellic Ctec. Increasing laccases dosage from 2 to 10 IU/g solid led to a visible reduction of hydrolysis efficiency, suggesting possible toxicity/inhibition effects above a given level. Applying a washing step showed to be efficient in removing some of the formed phenolics, while its overall benefit seemed to depend on the extension of laccases action before being washed. When an efficient laccases treatment was conducted before the washing step, involving reduced mass transfer limitations and an adequate period of time, subsequent enzymatic hydrolysis produced nearly 30 % more glucose for a 8 % solids load. In accordance, there was also a significant increase on the levels of free Cel7A after hydrolysis of this new solid, suggesting important modifications on the levels and structure of its lignin. The utilization of laccases on the hydrolysis of lignocellulosic biomass may represent an interesting element for more efficient and economic processes.This work had the financial support from the Portuguese Foundation for Science and Technology under the scope of Project EcoTech (POCI-01-0145-FEDER-032206). The authors also acknowledge RAIZ for kindly providing the residues of eucalyptus bark.info:eu-repo/semantics/publishedVersio