Ensino com Temas: Uma Experiência no Curso de Licenciatura em Física

A contextualização de conceitos científicos apresenta-se como estratégia pedagógica para tornar os conteúdos curriculares socialmente relevantes e promover maior articulação com as vivências, saberes e concepções dos alunos. Esses aspectos devem estar presentes ao longo da formação do futuro professor e é fundamental promover oportunidades de vivenciar abordagens pedagógicas que levem a atitudes e compreensões que possam vir a desenvolver com seus futuros alunos. É nesse contexto que foi proposta a incorporação de temas em uma disciplina oferecida para o curso de Licenciatura em Física-IFUSP, que trata de fenômenos oscilatórios e ondas mecânicas, uma vez que esses fenômenos são observados em outras áreas da Física, com aplicações em diversas áreas da ciência. A escolha dos temas se deu de maneira a ilustrar a aplicação dos conceitos científicos abordados na disciplina em outras áreas de conhecimento, como, por exemplo, no estudo de clima, geofísica, astronomia e economia, e devido a suas implicações sociais e ambientais. Na programação da disciplina, grupos de alunos tornaram-se responsáveis pela apresentação desses temas na forma de seminários curtos inseridos nas aulas. Abriu-se, assim, um espaço interdisciplinar, no qual os alunos prepararam o material didático, o que exigiu, por parte deles, uma reflexão sobre o processo de aprendizagem e a relação entre o conteúdo da disciplina e sua vinculação com questões atuais com dimensões sociais, econômicas e tecnológicas. O ambiente criado favoreceu o compartilhamento de saberes dos alunos, a criação de vínculos sociais mais sólidos na sala de aula e o aumento da autoestima desses estudantes, que contribuem para a permanência no curso.The contextualization of the scientific concepts presents itself as a pedagogical strategy to make the curricular contents socially relevant and to promote greater articulation with the experiences, knowledge and conceptions of the students. These aspects must be present throughout the formation of future teachers and it is fundamental to promote opportunities to experience pedagogical approaches that lead to the attitudes and conceptions that are expected be developed with their future students. In this context, it was proposed the incorporation of themes in a discipline offered for the Licentiate degree in Physics-IFUSP, which deals with oscillatory phenomena and mechanical waves, since these phenomena are observed in other areas of physics, with applications in several areas of science. The themes were chosen in order to illustrate the application of the scientific concepts addressed in the discipline in other fields of knowledge, such as in the study of climate, geophysics, astronomy and economy, and due to their social and environmental implications. In the planning of the discipline, groups of students became responsible for presenting these topics in the form of short seminars inserted in the classes. An interdisciplinary space was opened in which the students prepared the didactic material, which demanded, on their part, a reflection on the learning process and the relation between the content of the discipline and its connection with current issues with social, economic and technological dimensions. This environment favored the sharing of students’ knowledge, the creation of stronger social bonds in the classroom and the increase in the self-esteem of these students that contribute to the permanence in the course

The study the properties structurals and elastics of phases lamellar of lipid.

Lamellar systems composed of lipid bilayers have been widely used as model system\ud for investigating properties of biological membranes, interactions between membranes and with biomolecules. The composition of the membrane determines its\ud three dimensional shape and its properties such as rigidity and compressibility\ud which play an important role on membrane fusion, protein adhesion, interactions\ud between proteins, etc. We present a systematic study of a lamellar system composed of lecithin and a commercial co-surfactant (Simusol), which is a mixture of\ud ethoxylated fatty acids. Using X ray scattering and a new procedure to fit X-ray\ud experimental data, we determine relevant parameters characterizing the lamellar\ud structure, varying membrane composition from 100% of lecithin to 100% of Simulsol. We present experimental data illustrating the swelling behavior for the membrane of different compositions and the respective behavior of the Caillé parameter.\ud From and GISAXS experiments on oriented films under controlled humidity we investigate the compressibility of the lamellar phase and the effect of incorporating\ud co-surfactant. Combining the Caillé parameter and compressibility studies we determine the bending rigidity of membranes. The results obtained with this experimental approach and new procedure to fit X-ray experimental allows us to identify\ud structural changes in the bilayer depending both on hydration and co-surfactant\ud content, with implications on elastic properties of membranes

Outcomes of elective liver surgery worldwide: a global, prospective, multicenter, cross-sectional study

Background: The outcomes of liver surgery worldwide remain unknown. The true population-based outcomes are likely different to those vastly reported that reflect the activity of highly specialized academic centers. The aim of this study was to measure the true worldwide practice of liver surgery and associated outcomes by recruiting from centers across the globe. The geographic distribution of liver surgery activity and complexity was also evaluated to further understand variations in outcomes. Methods: LiverGroup.org was an international, prospective, multicenter, cross-sectional study following the Global Surgery Collaborative Snapshot Research approach with a 3-month prospective, consecutive patient enrollment within January–December 2019. Each patient was followed up for 90 days postoperatively. All patients undergoing liver surgery at their respective centers were eligible for study inclusion. Basic demographics, patient and operation characteristics were collected. Morbidity was recorded according to the Clavien–Dindo Classification of Surgical Complications. Country-based and hospital-based data were collected, including the Human Development Index (HDI). (NCT03768141). Results: A total of 2159 patients were included from six continents. Surgery was performed for cancer in 1785 (83%) patients. Of all patients, 912 (42%) experienced a postoperative complication of any severity, while the major complication rate was 16% (341/2159). The overall 90-day mortality rate after liver surgery was 3.8% (82/2,159). The overall failure to rescue rate was 11% (82/ 722) ranging from 5 to 35% among the higher and lower HDI groups, respectively. Conclusions: This is the first to our knowledge global surgery study specifically designed and conducted for specialized liver surgery. The authors identified failure to rescue as a significant potentially modifiable factor for mortality after liver surgery, mostly related to lower Human Development Index countries. Members of the LiverGroup.org network could now work together to develop quality improvement collaboratives

Medida de espessura de filmes finos com interferômetro de haidinger

Orientador: Jaime FrejlichDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb WataghinResumo: Apresentamos um método não destrutivo para medida de espessura de filmes finos transparentes depositados em substratos transparentes, usando um interferômetro de Haidinger. A partir das frações de interferência, medidas para vários comprimentos de onda, e do índice de refração para um único comprimento de onda, determinamos a espessura do filme e sua dispersão cromática, através de um procedimento analítico-numéricoAbstract: We introduce a non-destructive method for the thickness measurement of thin transparent films coated on transparent substrates, using a Haidinger interferometer. From the interference fractions measured for various wavelengths, and the refraction index for only one wavelength, we determine the film thickness and its chromatic dispersion through an analytic-numeric procedureMestradoFísicaMestre em Físic

Study of chemical stability and properties of anchoring in lyotropic liquid crystals

Apresentamos um novo cristal liquido liotrópico, onde o álcool (utilizado nas misturas liotrópicas com fases nemáticas biaxial e uniaxiais), é substituído por um detergente. Essa nova mistura é composta por laurato de potássio, cloreto de decilamônia e água e apresenta fases nemáticas uniaxiais, calamitica e discótica, e biaxial. É apresentada uma superfície do diagrama de fases dessa mistura e são determinados alguns parâmetros microscópicos. Nesse estudo são utilizadas as técnicas de microscopia óptica de luz polarizada, conoscopia e difração de raios x. É feito um estudo comparativo da estabilidade química desse sistema, em relação à mistura com álcool. É feito um estudo sistemático das propriedades de ancoramento de cristais líquidos liotrópicos em superfícies de vidro (lisas e com ranhuras), utilizando a técnica de microscopia óptica de luz polarizada. Um novo fenômeno é observado, o deslizamento do diretor na superfície de contorno. Um modelo qualitativo, é proposto, baseado na existência de urna bicamada anfifílica, com defeitos, na interface. São determinados os tempo de orientação e tempo de relaxação para as amostras e os resultados são comparados às previsões do modelo proposto. Também é apresentado um método de tratamento de superfícies de vidro para orientação de cristais líquidos liotrópicos.We present a new lyotropic liquid crystal, where the alcohol (used in lyotropic mixtures that present biaxial and uniaxial nematic phases) is substituted by a detergent. This new mixture is composed by potassium laurate, ammonium decylchloride and water and presents uniaxial and biaxial nematic phases. A surface of the phase diagram os this mixture is presented and some microscopical parameters are determined. In this investigation the techniques of polarised optical microscopy, conoscopy and X ray- diffraction are used. The chemical stability of this mixture is compared to the mixture with alcohol. The anchoring properties of lyotropic liquid crystals on glass surfaces (smooth and with grooves) are also investigated, using optical polarising microscopy. A new phenomen is observed, the gliding of the director at the boundary surfaces. A qualitative model is proposed, based on the existence of an anphiphilic bilayer with defects, at the interface. The orientation and relaxation times are determined and compared to the ones predicted by the model. It is also presented, a method for treating glass surfaces with ferrofluid that is applied to orient lyotropic liquid crystal samples

Study of chemical stability and properties of anchoring in lyotropic liquid crystals

Apresentamos um novo cristal liquido liotrópico, onde o álcool (utilizado nas misturas liotrópicas com fases nemáticas biaxial e uniaxiais), é substituído por um detergente. Essa nova mistura é composta por laurato de potássio, cloreto de decilamônia e água e apresenta fases nemáticas uniaxiais, calamitica e discótica, e biaxial. É apresentada uma superfície do diagrama de fases dessa mistura e são determinados alguns parâmetros microscópicos. Nesse estudo são utilizadas as técnicas de microscopia óptica de luz polarizada, conoscopia e difração de raios x. É feito um estudo comparativo da estabilidade química desse sistema, em relação à mistura com álcool. É feito um estudo sistemático das propriedades de ancoramento de cristais líquidos liotrópicos em superfícies de vidro (lisas e com ranhuras), utilizando a técnica de microscopia óptica de luz polarizada. Um novo fenômeno é observado, o deslizamento do diretor na superfície de contorno. Um modelo qualitativo, é proposto, baseado na existência de urna bicamada anfifílica, com defeitos, na interface. São determinados os tempo de orientação e tempo de relaxação para as amostras e os resultados são comparados às previsões do modelo proposto. Também é apresentado um método de tratamento de superfícies de vidro para orientação de cristais líquidos liotrópicos.We present a new lyotropic liquid crystal, where the alcohol (used in lyotropic mixtures that present biaxial and uniaxial nematic phases) is substituted by a detergent. This new mixture is composed by potassium laurate, ammonium decylchloride and water and presents uniaxial and biaxial nematic phases. A surface of the phase diagram os this mixture is presented and some microscopical parameters are determined. In this investigation the techniques of polarised optical microscopy, conoscopy and X ray- diffraction are used. The chemical stability of this mixture is compared to the mixture with alcohol. The anchoring properties of lyotropic liquid crystals on glass surfaces (smooth and with grooves) are also investigated, using optical polarising microscopy. A new phenomen is observed, the gliding of the director at the boundary surfaces. A qualitative model is proposed, based on the existence of an anphiphilic bilayer with defects, at the interface. The orientation and relaxation times are determined and compared to the ones predicted by the model. It is also presented, a method for treating glass surfaces with ferrofluid that is applied to orient lyotropic liquid crystal samples

Supramolecular polymorphism of DNA in non-cationic L(alpha) lipid phases

The structure of a complex between hydrated DNA and a non-cationic lipid is studied, including its phase diagram. The complex is spontaneously formed by adding DNA fragments (ca. 150 base pairs in length) to non-cationic lipids and water. The self-assembly process often leads to highly ordered structures. The structures were studied by combining X-ray scattering, fluorescence and polarized microscopy, as well as freeze-fracture experiments with transmission electron microscopy. We observe a significant increase of the smectic order as DNA is incorporated into the water layers of the lamellar host phase, and stabilization of single phase domains for large amounts of DNA. The effect of confinement on DNA ordering is investigated by varying the water content, following three dilution lines. A rich polymorphism is found, ranging from weakly correlated DNA-DNA in-plane organizations to highly ordered structures, where transmembrane correlations lead to the formation of columnar rectangular and columnar hexagonal superlattices of nucleotides embedded between lipid lamellae. From these observations, we suggest that addition of DNA to the lamellar phase significantly restricts membrane fluctuations above a certain concentration and helps the formation of the lipoplex. The alteration of membrane steric interactions, together with the appearance of interfacial interactions between membranes and DNA molecules may be a relevant mechanism for the emergence of highly ordered structures in the concentrated regime.French Ministry of Foreign and European AffairsCAPES-CoFECUB[558/07