DSpace Coleção:http://repositorio.uem.br:8080/jspui/handle/1/10692024-03-28T11:14:47Z2024-03-28T11:14:47ZVisualização em geometria : um estudo com ingressantes e concluintes de um curso de licenciatura em matemáticaPolizeli, Raquelhttp://repositorio.uem.br:8080/jspui/handle/1/59202020-10-15T14:42:05Z2020-01-01T00:00:00ZTítulo: Visualização em geometria : um estudo com ingressantes e concluintes de um curso de licenciatura em matemática
Autor(es): Polizeli, Raquel
Abstract: RESUMO: Esta pesquisa tem por objetivo investigar a atividade de Visualização na resolução de tarefas de Geometria, pelos integrantes de dois grupos de estudantes de um curso de Licenciatura em Matemática de uma Universidade ao norte do Estado do Paraná. A motivação para este estudo deu-se a partir da participação da pesquisadora no Grupo de Pesquisa em Ensino de Geometria – GPEG, no qual a Visualização era um dos principais temas de interesse na época. Este trabalho é de cunho qualitativo, pautado no paradigma interpretativo e segue a modalidade estudo de casos múltiplos. Teve como unidades de análise um grupo formado por oito acadêmicos ingressantes no curso de Licenciatura em Matemática e outro formado por oito membros que já haviam cursado as disciplinas de Geometria deste curso. Nessa pesquisa a Visualização Geométrica entendida como uma atividade cognitiva intrinsecamente semiótica, na qual são articuladas imagens mentais, representações externas, ações de interpretação para a visualização e as habilidades para a visualização, de modo que proporcione a integração entre as funções heurística e discursiva. Essa adoção teve como base as aproximações delineadas neste estudo entre as concepções de Duval e Gutiérrez. O instrumento de análise escolhido para a produção dos dados desta pesquisa se constituiu a partir de uma entrevista semiestruturada, cuja estrutura foi pautada em seis tarefas do tipo problema de exploração, no contexto geométrico em que a Visualização é requerida. Os dados foram analisados a partir de procedimento metodológico descritivo, em que foram estabelecidas categorias a priori, pautadas na concepção de Visualização Geométrica adotada. Observou-se pela análise realizada que a produção de imagens mentais esteve presente no raciocínio dos entrevistados dos dois grupos, bem como o uso das representações externas, auxiliando no desenvolvimento e na expressão para a comunicação do raciocínio. Pôde-se notar que o processo de interpretação de informações obtidas a partir de imagens foi o mais requerido nas tarefas escolhidas. Observou-se que as habilidades foram mobilizadas como esperado em cada tarefa por parte de alguns dos participantes dos dois grupos, porém, nota-se que são necessárias estratégias para a promoção do seu uso e desenvolvimento, principalmente nos membros do grupo dos ingressantes. Pode-se inferir que as funções heurística e discursiva são empregadas nas resoluções das tarefas e que a coordenação entre elas ocorre, mas observou-se que o emprego dessas funções pode ser melhorado, visto que são notadas dificuldades, principalmente em relação ao emprego da função discursiva, por parte dos integrantes dos dois grupos e que essas dificuldades são acentuadas nas produções dos ingressantes. Também foram percebidas dificuldades com respeito a conceitos como quadrado, triângulo retângulo, rotação, translação. Observou-se que ao invés de evocarem o conceito em si, os entrevistados mobilizam uma imagem do conceito que é limitada do ponto de vista matemático, evidenciando dificuldade na formalização e em relação a características que definem os objetos matemáticos. Pôde-se observar ainda que os argumentos apresentados nas respostas das tarefas pelos participantes do grupo dos iniciantes eram mais sucintos, perceptivos e intuitivos quando comparados aos apresentados pelos membros do outro grupo. E como era esperado, o grupo daqueles que já haviam cursado as disciplinas de Geometria do curso tiveram um melhor desempenho em suas respostas, embora também se observe argumentos perceptivos e intuitivos em suas respostas. De modo geral, a esta pesquisa evidencia a necessidade de busca de estratégias que promovam o conhecimento, o manuseio e a aplicação dos elementos que compõe a Visualização Geométrica, em especial, as duas ações de interpretação da informação, as habilidades de visualização, as funções heurística e discursiva. Para que a visualização seja de fato efetiva e contribua com a aprendizagem em Geometria.; ABSTRACT: This research aims to investigate the Visualization activity in Geometry tasks solution, by two different groups of undergraduate students from a Mathematics Degree course at a State University in Northern Paraná. The thing that motivated this study is the involvement of the researcher at the Research Group in Teaching Geometry- GPEG, which had Visualization as one of the main topics of interests at that time. This is a qualitative research grounded on the interpretive paradigm and the multiple case study. The units of analysis consist of a group of eight Mathematics Degree’s freshmen and another group composed by eight students who had previously attended the Geometry subjects. In this research, Geometric Visualization is thought to be a cognitive activity intrinsically semiotic, in which mental images, external representation, elements of interpretation for image view, and visual abilities are articulated, so that, there is an integration among heuristic and discursive functions. This choice was based on outlined approximations in this study within Duval and Gutiérrez’s rationale. The analysis instrument chosen for the production of the data was constituted from a semi-structured interview, whose structure was guided in six tasks of the type exploration problem, in the context geometric where the Visualization is required. Data were analysed from the descriptive research method, in which categories were established based on the Geometric Visualization idea applied. It was observed that the production of mental images was present in both interviewees groups’ reasoning, as well as the use of external representations, supporting the development and expression of the reasoning communication. The interpretation process of information taken from images was noticed to be one of the most required on the chosen tasks. Abilities were noticed to be applied as it was expected in each one of the tasks, considering only some of the people from both groups, however some strategies are needed to promote their use and development, specially from the freshmen group. That can be inferred that heuristic and discursive functions are used in tasks solutions, and there is a coordination between them, in spite of this, that was observed that the application of these two functions can be enhanced, considering that difficulties are noticed, mainly taking into account the two groups discursive function usage, and these difficulties are stronger in freshmen productions. Difficulties concerning concepts such as square, right triangle, rotation and translation were also noticed. That was perceived that, instead of remembering the concept itself, the interviewees mobilized a concept image, which is restricted from the mathematics perspective, highlighting the difficulty in formalize and also in regard to the features that define mathematical objects. It could be noticed that the arguments on the freshmen’s answers were more concise, perceptive, intuitive than those presented by the members of the other group. Furthermore, as a foregone conclusion, those who had already attended the Geometry subjects, had a better outcome in their answers, even though that perceptive and intuitive arguments were noticed in their answers. In general, this research highlights the need to search for strategies that promote the knowledge, handling and application of the elements that make up Geometric Visualization, in particular, the two actions of interpretation of information, visual abilities, heuristic and discursive functions. For Visualization to be truly effective and contribute to learning in Geometry.
Descrição: Orientador: Prof. Dr. Valdeni Soliani Franco; Tese (doutorado em Educação para a Ciência e a Matemática) - Universidade Estadual de Maringá, 20202020-01-01T00:00:00ZUtilização de polissacarídeos para desenvolvimento de materiais avançados : nanowhiskers de quitina/quitosana e microesferas de amidoPereira, Antonio Guilherme Bassohttp://repositorio.uem.br:8080/jspui/handle/1/39302018-10-15T19:19:02Z2013-01-01T00:00:00ZTítulo: Utilização de polissacarídeos para desenvolvimento de materiais avançados : nanowhiskers de quitina/quitosana e microesferas de amido
Autor(es): Pereira, Antonio Guilherme Basso
Abstract: The study developed in this Thesis has two main focuses. In the first one, the preparation of chitin and chitosan nanowhiskers and their application in the preparation of electrospun nanofibers based on cellulose acetate were described. Pure chitin was isolated from crab shell chitin at 75 % yield and hydrolyzed (3 N HCl, 30 mL/g, 104 ºC) to chitin nanowhiskers (CtNWs) at 65 % yield with degree of acetylation (DA) of 81 % confirmed by FTIR. TEM analysis showed the CtNWs dimensions are 16 nm (width) and 214 nm (length) with aspect ratio of 13. CtNWs self-assemble during freezing drying into layers containing sub-micron structures. Chitosan nanowhiskers (CsNWs) were derived from deacetylation of CtNWs under alkaline treatment. A systematic study on CtNWs condition (suspension or freeze-dried), temperature and reaction time on deacetylation and on yield of final product was performed. FTIR revealed that DA of CsNWs was ca. 60 % independent on reaction time. It was shown the deacetylation occurs preferentially at the surface of CtNWs and the extension of reaction increases with increasing of reaction time, as evidenced by the increase of positive charges in zeta potential measurements, associated to loss of crystallinity from 86 % (CtNWs) to ca. 50 % (CsNWs) and reduction of yield. However, the rod-shape morphology was maintained. TGA and DSC data showed only slightly variations between CtNWs and CsNWs corroborating to zeta potential and FTIR data which suggest surface deacetylation. Furthermore, it was possible to follow the deacetylation reaction through 1H NMR e 13C NMR spectroscopy. The 1H NMR spectra presented good resolution considering the fact that the samples are nanocrystals (solids). Nanocomposites electrospun nanofibers based on cellulose acetate and chitin nanowhiskers (CtNWs) were prepared by electrospinning (14 kV, 1 mL/h, distance of 25 cm, concentration of 15 %) a suspension prepared in ternary solvent system: Acetone/DAMAc/H2O (61.7/33.3/5 %-v/v/v). The addition of CtNWs at 2.5 % induced a decrease in the average diameter of fibers from 563 nm (control) to 240 nm. It was also showed that the surface properties of electrospun nanofibers could be tuned by the electrostatic adsorption of CsNWs. Biological assays showed the nanofibers based on pure CA, or those containing CtNWs or CsNWs promoted an increase in the VERO cell growth. Besides, the nanofibers with chitosan nanowhiskers adsorbed at the surface have antibacterial activity against Escherichia coli with 99 % of CFU death in 24 h. Similarly, CtNWs and CsNWs suspensions presented antibacterial activity, as well. For 24 h of contact the bacterial death was 85 % and 98 % for CtNWs and CsNWs, respectively. In the second focus of this Thesis, crosslinked microspheres based on starch, previously modified by the insertion o vinyl groups, were prepared to act as oral curcumin deliverer, drug that presents antitumor activity. The microspheres showed high loading efficiency (~90%) even in loading solution with different CUR concentrations. In vitro release assays data showed that the CUR release is governed by anomalous transport (n = 0.73, contribution of both diffusion and swelling) and pH-dependent. Cytotoxicity assays showed that starch-mod/MBA microspheres could improve the cytotoxicity of CUR towards Caco-2 and HCT-116 cell lines up to 40 times than that found for pure CUR. This behavior was attributed to the slowly and sustained release of CUR from the microspheres, avoiding premature degradation.2013-01-01T00:00:00ZUtilização de polissacarídeos para a obtenção de biocompósitos multifuncionais empregando técnicas avançadas de polimerização controlada e de microemulsão via ultrassonicaçãoMauricio, Marcos Robertohttp://repositorio.uem.br:8080/jspui/handle/1/67042023-08-30T20:03:11Z2014-01-01T00:00:00ZTítulo: Utilização de polissacarídeos para a obtenção de biocompósitos multifuncionais empregando técnicas avançadas de polimerização controlada e de microemulsão via ultrassonicação
Autor(es): Mauricio, Marcos Roberto
Abstract: RESUMO: Polissacarídeos constituem uma classe de polímeros com vasto interesse de estudos no desenvolvimento de aplicações industriais e tecnológicas. Atualmente os polissacarídeos que estão sendo amplamente investigados são a celulose, devido à extração dos nanocristais de celulose (CNC), o amido e as ciclodextrinas (CDs). O desenvolvimento de biomateriais micrométricos empregando estes substratos apresenta potencial aplicação em inúmeras áreas, principalmente a área de materiais, farmacêuticas e médicas. A funcionalização destes materiais utilizando nanopartículas inorgânicas do tipo magnetita ou ouro possibilita a criação de biomateriais "inteligentes", os quais podem apresentar resposta a estímulos externos apropriados. Neste trabalho foi explorado inicialmente o amido e a amilose para obtenção de micropartículas aplicando a técnica de ultrassonicação. As micropartículas de amido foram reticulados com CNC e aplicados como sistemas de liberação controlada de fármacos. As micropartículas obtidas a partir de amilose foram carregados com magnetita para obtenção de biomateriais "inteligentes". Além disso, os CNC foram aplicados como substratos para polimerização controlada do tipo ATRP. O emprego do CNC em processo de polimerização controlada possibilita a criação de materiais com arquitetura definida, no caso polímeros escova. O polímero escova obtido foi funcionalizado com nanopartículas magnéticas e aplicado em processos de adsorção. Por fim, foi explorada a ?-ciclodextrina (?-CD) como macroiniciador para obtenção de polímeros estrela utilizando a técnica de ATRP. Nesta etapa foi explorada a polimerização do monômero metacrilato de glicidila (GMA) juntamente com a posterior modificação pós polimerização. O polímero estrela obtido foi utilizado como agente redutor e estabilizador de nanopartículas de ouro, obtendo suspensões coloidais extremamente estáveis. De modo geral os polissacarídeos explorados neste trabalho e as técnicas empregadas de ultrassonicação e de polimerização controlada do tipo ATRP possibilitaram a obtenção de materiais com diferentes morfologias, os quais apresentaram potenciais aplicações para diversos campos; ABSTRACT: Polysaccharides embody a class of polymers with extensive interest in studies for the development of industrial and technological applications. Nowadays, cellulose (due to the extraction of cellulose nanocrystals (CNC)), starch, and cyclodextrins (CDs) are appealing and widely investigated polysaccharides. The development of micrometric biomaterials using these substrates has potential application in many areas, mainly related to biomaterials, pharmaceutical and medical research fields. The functionalization of these materials using inorganic nanoparticles, such as magnetite or gold nanoparticles, enables the creation of "smart" biomaterials, which may make appropriate response to external stimuli. In this work, initially amylose (starch) was explored to obtain microparticles applying ultrasonication technique. Starch microparticles were cross-linked with CNC and applied as controlled drug delivery systems. Microparticles obtained from amylose were loaded with magnetite to obtain "smart" biomaterials with magnetic properties. Furthermore, CNC were applied as substrates for the controlled ATRP polymerization. The use of CNC in controlled polymerization process enables the creation of materials with defined architecture known as brush polymers. The obtained polymer brush functionalized with magnetic nanoparticles were successfully applied for adsorption processes. Finally, we explored the ?-cyclodextrin (??CD) as macroinitiator for obtaining star polymers using ATRP technique. The polymerization of the monomer glycidyl methacrylate (GMA) with subsequent post-polymerization modification was carried out in this step. The obtained star polymer was used as a reducing agent and stabilizing the gold nanoparticles, obtained extremely stable colloidal suspensions. In summary, polysaccharides used along with ultrasonication and controlled polymerization (ATRP) techniques provide materials with special and unique morphologies, which showed potential applications for various fields
Descrição: Orientador: Prof. Dr. Adley Forti Rubira; Tese (doutorado em Química) - Universidade Estadual de Maringá, 20142014-01-01T00:00:00ZO trabalho de campo e a educação ambiental na formação continuada de professoresBerezuk, Paulo Augustohttp://repositorio.uem.br:8080/jspui/handle/1/45472018-04-23T19:38:11Z2015-01-01T00:00:00ZTítulo: O trabalho de campo e a educação ambiental na formação continuada de professores
Autor(es): Berezuk, Paulo Augusto
Abstract: The importance of Environmental Education for the scientific and citizen formation has presented a huge increasing in the last decades due to the intense environmental degradation in the planet. Because of this concerning, there are teachers from several levels of teaching who are working with Environmental themes on their classes. However, although the Environmental Education is essential for students' formation, this sort of teaching still deals with strong resistance if you consider its development as an actual transformation proposal in schools nowadays. This kind of situation provokes the decreasing and even the lack of lessons on Fieldwork, for the teaching practice. Furthermore, it also prevents students from having the opportunity of witnessing the complexity, the diversity and the extent of the natural phenomena. Thus, this research has investigated how the Fieldwork is inset in the Environmental Education, which is developed by teachers. Moreover, this research contributes with the continuing education of teachers, and it helps therefore with the improvement of teaching quality at schools. For this, we developed a qualitative and quantitative research type, and we divided it in two parts: interviewing teachers, and carrying out with a short-term course. We interviewed twenty-nine teachers from different subjects and from schools previously chosen in order to obtain the data for the first part of this research. We worked with a ten-question semi-structured questionnaire. The data analysis has been developed based on the analysis method of contents. The obtained data from the interviews has guided us to create themes we worked during the short-term course. We developed the analysis of this short-term course by the observation of the participants' behavior and speeches. Furthermore, the obtained data from the activities proposed was also analyzed in order to find out the participants' previous knowledge, as well as if it had been improved throughout the course. We could conclude that few teachers work with themes related to Sustainable Development, and none of the teachers have declared they work with the Critical Environmental Education theme. Almost every interviewed teachers have declared that they work with Environmental Education contents in their classes. However, they are much dependent on lectures and lessons without students participation for developing their approach. Considering the Fieldwork, we observed that the interviewed teachers have shown lack of knowledge. Moreover, during the short-term course, teachers have reported they did not know what are social representations and its connections to Environmental Education, as well as information about international and national histories of Environmental Education. We could also noticed that many teachers use to elaborate their Fieldwork plannings in an incomplete way, spoiling its application. In fact, several difficulties caused the decreasing of the frequency of fieldworks, as lack of financial resources and pedagogical support in schools as well. From discussions and practical activities, the short-term course could provide for most participants a changing related to their conceptions, causing an improvement on their knowledges about Environmental Education and also about Fieldwork.2015-01-01T00:00:00Z