Navegando por Data de Publicação, começando com "2019-03-22"

Filtrar resultados por ano ou mês

Agora exibindo 1 - 11 de 11

O uso da geometria fractal como ferramenta no ensino de progressões geométricas e logaritmos
(Universidade Federal de São Carlos, 2019-03-22) Vieira, Diogo Comin; Salvador, José Antonio; https://lattes.cnpq.br/2487171069472158; https://lattes.cnpq.br/4128546204648929
This essay is a study that seeks to introduce Fractal Geometry as a tool in Geometric Progressions and Logarithms teaching in high school, more precisely in the 1st (first) year, but the presented activities unfold a possibility of application in several Math teaching segments. The goal of this work is to provide theoretical basis and a didactical sequence that reaches several levels of contents mastery, so teachers may work the Fractal Geometry as a motivator agent at teaching and deepening the concepts that were studied in the classroom, also opening the possibility for an approach of themes such as Limits and Convergence of Sequence, even in an intuitive way. This didactical sequence application in the classroom starts with Fractal Cards cutting out, which is a playful (ludic) and funny activity, goes through the relations between Fractal and the subjects studied in high school, up until the development of general formulas and the demand of a certain algebraic mastery, ending in an interesting application of Logarithmic properties.
Modelos alternativos da TRI para dados politômicos
(Universidade Federal de São Carlos, 2019-03-22) Silva, Marcelo Andrade da; Bazán Guzmán, Jorge Luis; https://lattes.cnpq.br/7302778157579178; https://lattes.cnpq.br/5641187629276460
The item response theory (IRT) models for polytomous data are frequently used in the analysis of data coming from the behavioral and social sciences. From a practical point of view, polytomous data are more informative than dichotomous data, since it considers more than two response categories in each test item, making the models assigned to this type of data attractive. The purpose of this research is to explore alternative polytomous IRT models and their multidimensional extensions, filling some gaps in the literature. Specifically, the chapters of this work follow a construction sequence of IRT modeling. Firstly, we conducted a study to assist readers in choosing between two of the major polytomous IRT models in the one-dimensional context: the graded response (GR) model and the generalized partial credit (GPC) model. We conducted a sensitivity analysis of priors to choose a suitable priors scenario for each model and we verified the performance of some model comparison criteria against these models through a simulation study. Then, we extend the one-dimensional GPC model to the bifactor context, proposing the GPC-bifactor model, in which a global latent trait and specific latent traits are considered through an additive structure in its formulation. In addition, we flexibilize the structure of the GPC-bifactor model, making possible its use with other link functions beyond the usual logit, such as probit and clog-log. Then, we incorporate the relation between the items and the latent trait dimensions of the individuals in the formulation of the multidimensional item response theory (MIRT) models through the Q-matrix, a component present in the vast majority of cognitive diagnostic models (CDM), making it easy for users to express the item-trait relationship in MIRT models. Finally, we propose a validation method using the Q-matrix in MIRT models. In particular, we used in the study the multidimensional GPC model with Q-matrix embedded in its formulation. The different simulation studies and the applications performed in this research showed that these models are alternative models for the analysis of polytomous data and that can be used by the users in practice.
Retratos da escravidão em Vozes d’América (1864), de Fagundes Varella
(Universidade Federal de São Carlos, 2019-03-22) Mega, Rebeca Aparecida; Marques, Wilton José; https://lattes.cnpq.br/5763590592946918; https://lattes.cnpq.br/8084586094028727
Se presentan, en este trabajo, consideraciones acerca de la producción literaria de Fagundes Varella (1841-1875), sobretodo aquella cuyo temario reúne discusiones alrededor de una circunstancia peculiar: la esclavitud y la miseria humana del negro africano – condición que diseñó y sostuvo al Brasil desde el siglo XVI. Se considera, por ello, un texto representativo de una recopilación poética del escritor de los primeros cuatro años del decenio de 1860: o poema, “Mauro, o escravo”; la obra, Vozes d’América (1864). La implementación de temas esclavistas, si entendidos como disposiciones históricas que acentuaron la producción literaria de Varella, matizaron un público lector compuesto de círculos sociales propios de su convivencia en la línea Rio-São Paulo y pudieron no solamente anticipar la visada abolicionista que se manifestaba en el Romanticismo de aquel momento, sino también denunciar al tratamiento superficial que era ofrecido al problema de la esclavitud por parte del sistema político brasileño – hecho que afectó, inevitablemente, la dedicación literaria de la generación. Se observa que, en el decenio en cuestión, el autor trajo al ruedo el sentimiento antiesclavista y la conciencia del problemático pilar que sostenía la estructura socioeconómica brasileña mediante el empleo de retratos de la realidad esclavista de la provincia, en el poema considerado, y mediante la reverberación temática de símbolos asociados al universo de la esclavitud en otras composiciones. Este sentimiento, que ya había ventilado el comienzo del movimiento romántico por las manos del poeta Gonçalves Dias, recibió contornos más nítidos, por ejemplo, entre el 1861 y el 1869, con los poemas de Castro Alves, contemporáneo de Varella. Sin embargo, específicamente en el caso de Varella, se presenta la observación de que el poema “Mauro, o escravo” es lo que abre la recopilación Vozes d’América (1864) y el único que enfoca, con densidad y de modo inaugural, la cuestión esclavista, tanto en el libro cómo en la obra literaria de Varella de modo general. A este poema se destina especial enfoque, con el reto de validar al presupuesto de que Varella, casi siempre identificado por la buena o mala crítica como un ultra romántico decadente, puede que sea redescubierto y leído, también, como un poeta-autor-destaque del Romanticismo paulista y, cómo no, un poeta-crítico-osado por, justamente, haber puesto en discusión un asunto de tanto peso social para la época y cuyo retrato era, más allá de complejo, literariamente evitado.
Entre mágoas e sonhos do povo: Lima Barreto e o folclore urbano
(Universidade Federal de São Carlos, 2019-03-22) Carneiro, Daniel Machado Vivacqua; Marques, Wilton José; https://lattes.cnpq.br/5763590592946918; https://lattes.cnpq.br/2058759808670205
A stage of the great transformations that served as a vector of the modernization of Brazil in the passage from the nineteenth century to the twentieth century, Rio de Janeiro comprehended such a great diversity of people from all regions of the country, as well as foreigners, who took Lima Barreto to see it not only as Federal Capital, but also as the country's “spiritual capital”. The sorrows and dreams of the people represent a plunge of the chronicler of the suburb of Todos os Santos in the universe of customs and popular beliefs found in the city he loved so much. The present study tries to demonstrate that, like all the work in chronicle of the author, this series of texts about the Brazilian urban folklore represents a criticism to the modernization of the country done, particularly, from flagrant ones that reveal the incorporation of modern values in the popular culture. In it one can observe the comprehensive manner in which Lima Barreto portrays the people and it’s “spiritual transformation” reflecting on the future of the country and defending the ideal of a society of solidarity.
Programa de Habilidades Sociais com pais e professores: efeitos sobre educadores e crianças escolares
(Universidade Federal de São Carlos, 2019-03-22) Casali, Ivana Gisel; Del Prette, Zilda Aparecida Pereira; https://lattes.cnpq.br/8113238388739093; https://lattes.cnpq.br/7861631051569929
The literature points out the importance of social skills for the quality of interpersonal relationships, being learned, from a young age, in the interaction with other people. Children with an elaborate repertoire of social skills exhibit fewer behavioral problems and better academic performance, having more favorable perspectives in the future. When favorable, the educational practices of parents and teachers in the school and family environment are indicated as protective factors of the child development, minimizing or neutralizing risk factors. These practices should be based on a repertoire of general and educational social skills of these educational agents. However, there are still insufficient programs aimed at promoting this repertoire and, in particular, the systematic study of its impacts on the Brazilian population. Based on this, the present study had as main objective to evaluate a Social Skills Program for parents and teachers of school children, examining their effects: (1) direct, on the social repertoire of the agents education; and (2) indirect, on children in terms of social skills, behavioral problems and academic performance. After a pilot study, the program for teachers were conducted, with 18 sessions of 75 minutes in weekly frequency and the program for parents, with 17 sessions of 90 minutes, also weekly. Thirty parents, eight teachers and their children/students (N = 35) participated in four groups, one non-intervention control (CG) and three experimental groups: EG1, involving parents and teachers; EG2, teachers only; and EG3, only parents. The children's repertoire was evaluated through the Social Skills Assessment System (SSRS-BR2) and the School Performance Test (TDE); and parents e teachers was evaluated through the Social Skills Inventory (IHS-Del-Prette), Inventory of Educational Social Skills (IHSE-Parents and IHSE-Teachers) and the Parental Assessment Protocol (PAP). Statistical analyzes showed effects: (1) direct on the social repertoire of parents and teachers who participated in the sessions, when compared to the control group; and (2) indirectly on the repertoire of social skills and academic performance, greater for EG1 children, who benefited from the involvement of parents and teachers in the program. Among the teachers, there was a statistically significant change between pre and postintervention (cultivate affection, support and good mood) and a significant late effect in the follow-up in the global social skills score and in specific factors (self-defense assertiveness; affective-sexual assertiveness; reprove, restrict and correct behaviors). Among the parents, there were statistically significant differences between pre and post intervention in the global scores of social skills and educational social skills and in specific factors (assertiveness of social self-exposition; affective-sexual assertiveness; establish limits, correct and control; talk/dialogue). Finally, those children whose parents and teachers participated in the program (EG1) showed, after the intervention, a significant improvement in the overall score of self-rated social skills and academic performance and in specific indicators (assertiveness, assertiveness and social entrepreneurship; writing). The results suggest the effectiveness of the program and the importance of investing in the planning of interventions in the family and school environment as a way to contribute to the social-emotional development of schoolchildren, even as indirect targets of intervention. Programs that include triadic intervention, frequent in international research, and that advance the limitations pointed out in the present study could provide even more robust results in the area.
Obtenção de anticorpo monoclonal murino anti-cd25 através do cultivo do hibridoma pc-61 em biorreatores spinner em meio livre de soro
(Universidade Federal de São Carlos, 2019-03-22) Damada, Pedro Henrique; Suazo, Cláudio Alberto Torres; https://lattes.cnpq.br/9591447226240450; Anibal, Fernanda de Freitas; https://lattes.cnpq.br/4918261968772806; https://lattes.cnpq.br/0873656684206368
Cancer is one of the deadliest diseases in the world. Its treatment includes surgical, chemotherapeutic and radiotherapeutic methods, which, although efficient, are expensive, long and can have several side effects to the patient. In order to seek new methodologies, immunotherapy, a treatment based on stimulation of the immune system to control cancer, has been one of the most interesting. One of the most used immunotherapeutic methods for this purpose is based on the use of monoclonal antibodies (mAbs), high specificity glycoproteins that are gaining space and arousing interest due to the positive results have already obtained for different diseases, such as multiple sclerosis and breast cancer. The objective of this work was to optimize the culture of PC-61 hybridomas in spinner flask for the production of the anti-CD25 mAb, with serum free commercial medium (SFM) and with RPMI medium supplemented with fetal bovine serum (FBS), used as control. Two modes of operation were used: batch and fed batch, in order to compare the results and propose a better methodology of cultivation. In addition, the purification of the antibodies was done using the techniques of ion exchange chromatography and immunoprecipitation with protein G in Sepharose. As a result, by batch culture, it was possible to identify the behavior of the cells and to stipulate the best conditions to carry out batch culture. Thus, it was possible to prolong the pre-stationary phase of the culture where a higher production of monoclonal antibody was observed. The SFM medium presented the best results compared to RPMI (with FBS) in batch culture, it was found that the production of mAbs in SFM was 3 times higher than in RPMI (with FBS). Furthermore, through these cultures, cells have been noted to direct their metabolism to produce the antibody when the nutrient level in the culture medium is reduced, and stress conditions (without causing cell death) can lead to increased production of antibody. In relation to purification, the immunoprecipitation technique with G protein proved to be very efficient, mainly for the separation of the antibodies present in the supernatant of the SFM culture, which has low protein content. Therefore, the use of the SFM medium is a great alternative to the culture media supplemented with FBS, since, in certain conditions, it allows the obtaining of larger amounts of antibody, and ensures greater ease in the application of purification techniques, reducing production costs.
Nanoemulsões de óleos essenciais: mecanismos de estabilidade e interação com pectina em bionanocompósitos para aplicação em embalagens ativas
(Universidade Federal de São Carlos, 2019-03-22) Lorevice, Marcos Vinicius; Mattoso, Luiz Henrique Capparelli; https://lattes.cnpq.br/5839043594908917; https://lattes.cnpq.br/2975504886357030
Microbial growth is among the challenges impairing food preservation and shelf-life. Essential oils (EO) featuring antimicrobial and antioxidant activities denote an alternative for lessening the contents of synthetic additives that may be harmful to human health. The limitations due the low EO solubility in water and their poor stability in aqueous media have been suppressed by the use of nanoemulsions (NE), which feature kinetic stability, intensify the antimicrobial effect of EO, and allow their dispersions in aqueous systems such as those involving polysaccharides for applications as packaging materials. The objective of this study were i) the production of NE having rosemary or clove EO as dispersed phase through high-energy (microfluidization - MF) or low-energy (catastrophic phase inversion - CPI) emulsification methods; ii) the evaluation of the NE stability with regard to the surfactant content in relation to the dispersed phase; and iii) the NE incorporation into pectin films to investigate the interaction among the components and the effect of the surfactant content on the physicochemical and active properties of the nanocomposites. The NE were characterized as to their average droplet sizes, zeta potentials, colloidal stability, and morphology. The films were evaluated as to their film-forming viscosity, morphology, wettability by water as well as mechanical, antimicrobial, and antioxidant properties. Regardless of the EO, the CPI-produced NE presented average droplet sizes and zeta potentials ranging from 100 to 500 nm and from -10 to -1 mV, respectively, being surfactant concentration and location the major factors affecting polydispersity. The MF was more efficient than CPI because the former led to average diameters ranging from 10 to 100 nm, and surfactant content was the dominant factor. The rosemary NE obtained through MF were more stable against creaming than clove NE against sedimentation. Cryo-TEM images indicate quasi-spherical particles with polydisperse diameters for CPI and homogeneous pattern for MF. Dynamic light scattering experiments did not evidence electrostatic interactions among pectin and surfactant, but the increased viscosity for surfactant contents between 10 and 20 wt.% suggested possible hydrophobic interactions, which led to films with increased hydrophobicity as well as sponge-like internal for both pectin/surfactant and pectin/NE films. The tensile strength and elastic modulus were decreased for surfactant contents higher than 20 wt.%. Rosemary EO exhibited antioxidant activity by capturing 85% of DPPH radicals and presenting an EC50% value of 50% of the initial EO concentration. The EC50% was decreased in the nanocomposites because of EO loss through evaporation upon drying, without any effect of the surfactant. On the other hand, antimicrobial activity was not detected because of the EO diffusion towards the culture medium, which was limited by the surfactant quantity and low oil-soluble in aqueous culture medium. This reported study is innovative because it relates the properties of pectin/rosemary NE nanocomposites with the content and characteristics of the surfactant, paving the route for a novel understanding on the role played by each component on the active and physicochemical properties.
Modelos de Controle de Acesso Sensíveis ao Contexto com uso de Smart Contracts
(Universidade Federal de São Carlos, 2019-03-22) Souza, Marcos Vinicius Menezes Rodrigues de; Guardia, Hélio Crestana; https://lattes.cnpq.br/1780902767520967; https://lattes.cnpq.br/2834699287629948
The constant advances in ubiquitous computing and in the Internet of things (IoT) bring new challenges to access control systems, such as building a mechanism not dependent on a centralized trusted party, and the need to account for contextual data. Such characteristics may be required to enable IoT services in smart homes, smart cities, medical services, or even in mobile computer based health monitoring systems. In these distributed computing environments, direct device to device interactions are commonly based on service requests among the participants, which reinforce the need for flexible and scalable authenticity and confidentiality mechanisms. This work deals with the development of an access control model to address such challenges using a blockchain infrastructure. In the proposed method, services and contextual data are defined using smart contracts, and blockchain logs are used for distributed and trustful information management. Blockchain assets are associated with permissions, and their transfers are used to directly verify access control rights in service invocation requests. A reference implementation of the the proposed model has been developed using the Hyperledger system and the results show the viability of this methodology.
Caracterização microestrutural e mecânica da liga AA2024 conformada por spray e processada termomecanicamente
(Universidade Federal de São Carlos, 2019-03-22) Asato, Gabriel Hitoshi; Bolfarini, Claudemiro; https://lattes.cnpq.br/9231627080617037; Jorge Júnior, Alberto Moreira; https://lattes.cnpq.br/6360362248108490; https://lattes.cnpq.br/0739042399340119
This work aimed to evaluate the possibility of combining spray forming processing with mechanical processing techniques (for instance, extrusion, rotary forging, and equal-channel angular pressing (ECAP)) to be used as processing routes for reuse of aluminum alloys. In the specific case of the AA2024 alloy, in applications nobler than the intended for production of casting alloys. For such an aiming, the final alloy must have a refined microstructure, solubilized alloying elements, be entirely homogeneous, absent of porosity that can affect mechanical properties, and chemical composition similar to the as received alloy. Our results have shown that, after spray forming, the microstructure presented equiaxed grains with an average size of 50 μm, alloying elements more solubilized than the as received alloy and a significant fraction of porosity. Chemical analysis of the deposit showed chemical composition with a small variation in composition, but still inside the allowed values imposed by the ASTM standard. The deposit was machined into cylindrical samples to be processed by extrusion and rotary forging and square-like samples to be processed by ECAP. The combination of rotary forging and ECAP were also performed. After processing, microstructural characterizations were accomplished to verify porosity closing and microstructure refinement. Mechanical compression tests were conducted to evaluate the mechanical strength of the processed alloys compared to the as received one. Results obtained from mechanical tests for the alloys processed by extrusion and rotary forging presented higher values than for the initial alloy. However, ECAP presented a decrease in mechanical resistance. Concerning the microstructure, the grains remained elongated, characteristic of mechanically processed alloys without recrystallization, secondary phases were sufficiently solubilized, no coring effect was observed in grains, and the porosity was significantly reduced.
Nanomateriais semicondutores aplicados na fabricação de dispositivos eletroquímicos
(Universidade Federal de São Carlos, 2019-03-22) Carrico, Amanda; Moraes, Fernando Cruz de; https://lattes.cnpq.br/8597473049054728; https://lattes.cnpq.br/6308872004159807
This dissertation was subdivided into 3 different studies. In the first study, it was proposed the development of a photo-electrochemical system for the removal of caffeine in natural water samples. Photo-anodes made with bismuth vanadate (BiVO4) modified with reduced graphene oxide were developed and characterized. The number of layers deposited in the photo-anode, the potential difference applied in the photo-electrochemical system, the power, the wavelength and the positioning of the irradiated light were evaluated by linear scanning voltammetry. Finally, the proposed system promoted a removal of up to 99.1% for caffeine after 6 hours of photo-electrocatalytic treatment under pseudo first order kinetics. In the second study, a photo-electrochemical sensor was developed for the detection of dopamine through immobilization of bismuth vanadate and graphene quantum dots (GQDs) on a fluoride-doped tin oxide (FTO) electrode. The electrochemical and photo-electrochemical behavior of BiVO4/GQDs was studied using linear scanning voltammetry in a system with on/off lighting and electrochemical impedance spectroscopy under visible light irradiation. The analytical performance of the sensor was studied in the concentration range between 3.6 × 10-8 and 2.5 × 10-4 mol L-1. A limit of detection of 8.2 × 10-9 mol L-1 and a limit of quantification of 2.7 × 10-8 mol L-1 was estimated. The selectivity of the sensor was evaluated in the presence of ascorbic and uric acid in concentration values up to 10 and 100 times higher, respectively. Therefore, this sensor had potential to be applied in the monitoring of free dopamine in the urine of humans. In a third study, a method was developed for the simultaneous quantification of diclofenac, acetaminophen and caffeine in lake water samples, using a chemically modified voltammetric sensor with reduced graphene oxide (RGO) and silver nanoparticles ( AgNPs). For the simultaneous detection of these endocrine disruptors, the differential pulse voltammetry technique was used. A linear response of the current signals as a function of the endocrine disruptors concentration was obtained with detection limits in the order of 10-7 mol L-1, thus presenting potential to be applied in effluent treatment plants and in the online monitoring of the photo-electro-degradation process of environmental contaminants.
Estudo comparativo do efeito da temperatura na estabilidade e espectros de bioluminescência das luciferases de Phrixotrix hirtus e outros besouros bioluminescentes
(Universidade Federal de São Carlos, 2019-03-22) Oliveira, Gabriela de; Viviani, Vadim Ravara; https://lattes.cnpq.br/3942043373510668; https://lattes.cnpq.br/1539841107867462
Firefly luciferases have been extensively used as bioanalytical reagents and their cDNAs as reporter genes and bioimaging biosensors. Luciferases of fireflies, “rail-road” worm and "tec-tec" beetles, have different characteristics of thermostability, kinetics and spectrum of bioluminescence, being able to offer alternatives to increase the applications of these enzymes. However, most of these enzymes are unstable at temperatures above 30 ° C, and firefly luciferases exhibit bioluminescence spectra sensitive to temperature. In this thesis, we conducted an extensive study of the effect of temperature on the stability and bioluminescence spectra of recombinant luciferases from Brazilian bioluminescent beetles, and we used site-directed mutagenesis to increase the thermostability of red-light-emitting luciferase from Phrixotrix hirtus. The most thermostable luciferases were the ones that emitted the most shifted light to the blue within each family: that of the Elateridae Pyrearinus termitilluminans (534 nm), that of the Phengodidae Phrixotrix vivianii (546 nm) and that of the Lampyridae Amydetes vivianii (538 nm), confirming that emitting luciferases in the region from green to blue are more stable. All the pH-sensitive luciferases of fireflies studied here presented sensitivity of the bioluminescence spectrum to temperature. The luciferases with the most displaced bioluminescence spectrum for blue were also less temperature sensitive in the following order: Amydetes