19341 research outputs found
Sort by
O voo da Panapaná : dos corpos estranhos às corpas borboletas.
No full textPrograma de Pós-Graduação em Artes Cênicas. Departamento de Artes, Instituto de Filosofia, Artes e Cultura, Universidade Federal de Ouro Preto.A pesquisa intitulada “O Voo da Panapaná: dos corpos estranhos às corpas borboletas” tem como objetivo a construção simbólica de uma panapaná — um coletivo de bixas-borboletas — que transcende os medos, transmutando-os em orgulho de ser bixa, e desafiando a heteronormatividade compulsória, a cisgeneridade e o patriarcado. A partir da autodescoberta enquanto pessoa bixa e da ruptura com as expectativas da heterossexualidade compulsória, utilizo a performance como ferramenta para a criação de uma contra-esfera pública, especialmente voltada às minorias sexodissidentes, como meio de tensionar as fronteiras entre vida e arte. A pesquisa propõe uma análise da arte drag queen, das teorias queer/cuir e das linguagens cênicas da performance e do cabaré como formas de resistência e invenção de novas narrativas para essas corpas dissidentes. A metodologia se ancora no conceito de “antropofagya”, de Carlos Henrique Lucas Lima, que envolve apropriação, devoração, gongação e devolução de elementos da cultura do “normal” — tudo isso em constante metamorfose, sob uma perspectiva queer/cuir. Como desdobramento prático da pesquisa, desenvolvi um experimento que resulta na elaboração de um roteiro para uma possível performance intitulada “Seresta da Guguete: Hematomas de Amor”. Esse roteiro atua como dispositivo de criação de novas narrativas para esta corpa dissidente, provocando abalos (CIS)micos no mundo como o conhecemos, e explorando a arte drag como possibilidade de fuga, enfrentamento e reinvenção. A estrutura da pesquisa acompanha as fases do ciclo de vida da borboleta — ovo, lagarta, crisálida e borboleta —, alinhando cada etapa do processo investigativo a uma dimensão simbólica: da apresentação pessoal à emergência das reflexões finais.The research entitled “The Flight of the Panapaná: from Strange Bodies to Butterfly Bodies” aims to symbolically construct a panapaná—a collective of butterfly-queers (bixas-borboletas)—that transcends fear by transmuting it into pride in being a bixa, challenging compulsory heteronormativity, cisgenderism, and patriarchy. Arising from the process of self-discovery as a bixa person and a rupture with the expectations of compulsory heterosexuality, I employ performance as a tool to create a counter-public sphere, particularly oriented toward sex-dissident minorities, as a means of blurring the boundaries between life and art. This research proposes an analysis of drag queen art, queer/cuir theory, and the performative and cabaret languages as forms of resistance and invention of new narratives for these dissident bodies. The methodology is grounded in the concept of “antropofagya” by Carlos Henrique Lucas Lima, which involves the appropriation, devouring, mocking, and re-delivery of elements from “normal” culture—all in constant metamorphosis, through a queer/cuir lens. As a practical development of the research, I developed an experiment that resulted in the elaboration of a script for a potential performance entitled “Guguete’s Serenade: Bruises of Love”. This script functions as a device for creating new narratives for this dissident body, provoking (CIS)mic disruptions in the world as we know it, and exploring drag art as a means of escape, confrontation, and reinvention. The structure of the research follows the life cycle of the butterfly—egg, caterpillar, chrysalis, and butterfly—aligning each stage of the investigative process with a symbolic dimension: from personal presentation to the emergence of final reflections
Padronização de um modelo murino de cicatrização hipertrófica e avaliação in vitro de extratos de própolis verde sobre a viabilidade celular.
No full textPrograma de Pós-Graduação em Ciências Farmacêuticas. Escola de Farmácia, Universidade Federal de Ouro Preto.Histopatologicamente, o processo de formação de cicatrizes hipertróficas é descrito como um transtorno fibroproliferativo que afeta à derme reticular, caracterizado por um microambiente inflamatório desregulado e associado ao desequilibro entre os mecanismos de sínteses, deposição e degradação de tecido fibrovascular na área da lesão. O desenvolvimento de modelos experimentais para o estudo da formação de cicatrizes hipertróficas é fundamental para a compreensão dos mecanismos fisiopatológicos inerentes a essa condição. No presente estudo foi proposto o desenvolvimento de um modelo murino de implante subcutâneo de esponja a longo prazo para mimetizar a cinética inflamatória e fibrovascular observada nas fases proliferativa, maduração e remodelação do processo de formação de cicatrizes hipertróficas. Dessa forma, discos de esponja de poliéster poliuretano foram implantados subcutaneamente em camundongos Swiss durante períodos de 15, 30 e 45 dias. Análises histomorfométricas e imuno-histoquímicas foram realizadas utilizando a coloração H&E, picrosirius red e imunohistoquímica de α-SMA. Adicionalmente, foi realizada a quantificação da expressão da citocina TGF-β1. As análises histomorfométricas evidenciaram que houve uma diminuição progressiva na área ocupada por vasos sanguíneos ao longo dos períodos avaliados. No período de 15 dias de implante, observou-se um maior número de vasos sanguíneos com um área inferior a 100 μm2 em comparação com os grupos de 30 e 45 dias. A área ocupada por fibras colágenas maduras e a área imunomarcada com α-SMA aumentaram ao longo dos períodos avaliados. No período de 30 dias de implante, evidenciou-se a estabilização na deposição de fibras colágenas maduras e imaturas, bem como na expressão da citocina TGF-β1. Adicionalmente, foi realizada a caracterização química e a avaliação do efeito de dois extratos de própolis verde sobre a viabilidade celular, visando sua aplicação em um modelo murino de cicatrização hipertrófica. A caracterização química dos extratos de própolis verde EAP1 e EAP2 foi realizada pelo método de cromatografia gasosa acoplada à espectrometria de massas (CG-MS). Foram realizados ensaios de viabilidade celular para determinar o efeito dos extratos na viabilidade de fibroblastos murinos da linhagem L929 e em células embrionárias de rim humano (HEK-293), por meio do ensaio de viabilidade celular MTT. Nossos resultados sugerem que o modelo de implante de discos de esponja a longo prazo mimetizou a cinética inflamatória e fibrovascular observada nas fases proliferativa, maduração e remodelação, características do processo de cicatrização hipertrófica. Assim, o período de 15 dias de implante mimetizou os eventos fibrovasculares observados na fase proliferativa; o período de 30 dias correspondeu à fase de maduração; e o período de 45 dias assemelhou-se à fase de remodelação. A caracterização química dos extratos demonstrou que o extrato EAP2 apresentou um maior número e variedade de compostos voláteis pertencentes às classes dos ácidos fenólicos, terpenos e ácidos graxos. Os ensaios de viabilidade celular demonstraram que o tratamento com ambos os extratos não alterou a viabilidade das células. Em conclusão, o modelo murino de implante de esponja mimetizou a cinética dos principais fenômenos inflamatórios e fibróticos observados nas fases proliferativa, maduração e de remodelação do processo de cicatrização hipertrófica humana. Por outro lado, a caracterização química de ambos os extratos revelou que o extrato EAP2 apresentou um maior número e variedade de compostos voláteis na sua composição. Finalmente, o tratamento com ambos os extratos não foi citotóxico para as linhagens celulares avaliadas.Histopathologically, the process of hypertrophic scar formation is described as a fibroproliferative disorder that affects the reticular dermis, characterized by a dysregulated inflammatory microenvironment associated with an imbalance between the mechanisms of synthesis, deposition and degradation of fibrovascular tissue in the lesion area. The development of experimental models for the study of hypertrophic scar formation is essential for understanding the pathophysiological mechanisms inherent to this condition. In the present study, the development of a murine model of long-term subcutaneous sponge implantation was proposed to mimic the inflammatory and fibrovascular kinetics observed in the proliferative, maturation and remodeling phases of the hypertrophic scar formation process. Thus, polyester polyurethane sponge discs were implanted subcutaneously in Swiss mice for periods of 15, 30 and 45 days. Histomorphometric and immunohistochemical analyses were performed using H&E, picrosirius red and α-SMA immunohistochemistry staining. Additionally, quantification of the expression of the cytokine TGF-β1 was performed. Histomorphometric analyses showed a progressive decrease in the area occupied by blood vessels over the evaluated periods. In the 15-day implantation period, a greater number of blood vessels with an area of less than 100 μm2 was observed compared to the 30- and 45-day groups. The area occupied by mature collagen fibers and the area immunostained with α-SMA increased over the evaluated periods. In the 30- day implantation period, stabilization in the deposition of mature and immature collagen fibers was evidenced, as well as in the expression of the cytokine TGF-β1. Additionally, the chemical characterization and evaluation of the effect of two green propolis extracts on cell viability were performed, aiming at their application in a murine model of hypertrophic wound healing. The chemical characterization of the green propolis extracts EAP1 and EAP2 was performed by gas chromatography-mass spectrometry (GC-MS). Cell viability assays were performed to determine the effect of the extracts on the viability of murine fibroblasts of the L929 lineage and human embryonic kidney cells (HEK-293), using the MTT cell viability assay. Our results suggest that the long-term sponge disc implantation model mimicked the inflammatory and fibrovascular kinetics observed in the proliferative, maturation and remodeling phases, characteristic of the hypertrophic wound healing process. Thus, the 15-day implantation period mimicked the fibrovascular events observed in the proliferative phase; the 30-day period corresponded to the maturation phase; and the 45-day period resembled the remodeling phase. The chemical characterization of the extracts demonstrated that the EAP2 extract presented a greater number and variety of volatile compounds belonging to the classes of phenolic acids, terpenes and fatty acids. Cell viability assays demonstrated that treatment with both extracts promoted cell viability. In conclusion, the murine sponge implant model mimicked the kinetics of the main inflammatory and fibrotic symptoms observed in the proliferative, maturation and remodeling phases of the human hypertrophic healing process. On the other hand, the chemical characterization of both extracts revealed that the EAP2 extract presented a greater number and variety of volatile compounds in its composition. Finally, the treatment with both extracts was not cytotoxic to the cell lines evaluated
Production of a wood–plastic composite with wastes from disposable masks and corrugated cardboard : a sustainable post-pandemic approach.
No full textThe increasing demand for disposable textile products, personal care items, and electronic commerce has led to a substantial rise in waste generation, particularly from nonwoven fabric masks (wNWFs) and corrugated cardboard (wCC). This study assessed the feasibility of utilizing these waste materials, which were produced in significant amounts during the COVID-19 pandemic, as both a matrix and reinforcement filler in wood–plastic composites (WPCs). The WPC was fabricated using either two extrusion cycles or thermokinetic homogenization, with both processes being followed by hot pressing. The formulations consisted of virgin polypropylene (vPP), wNWF, and wCC in proportions of 45, 45, and 10 wt %, respectively. The results demonstrated that the composites produced via two extrusion cycles exhibited a tensile strength that was 85% higher and three-point flexural strength three times greater than those produced through thermokinetic homogenization. These findings contribute to advancements in scientific and technological knowledge and offer an efficient solution for managing these types of waste, which continue to be generated post-pandemic
Large-scale prediction of biological activities with Active-IT system.
No full textTraditional testing methods in pharmaceutical development can be time-consuming and costly, but in silico evaluation tools can offer a solution. Our in-house Active-IT system, a Ligand-Based Virtual Screening (LBVS) tool, was developed to predict the biological and pharmacological activities of small organic molecules. It includes four independent modules for generating molecular descriptors (3D-Pharma), machine learning modeling (ExCVBA), a database of bioactivity models, and a prediction module. Activity data collected from the PubChem BioAssay database was used for modelling SVM and Naïve Bayes machine learning methods. Models have been constructed using a recursive stratified partition method and validated through an activity randomization (Y-random) process. Over 3500 bioassays were modeled, each comprising 30 SVM and 30 Naïve Bayes models and 60 randomized models. Bioassays with low performance or discrimination between regular and randomized were discarded. Using the Active-IT system we have evaluated three bioactive compounds of Ayahuasca tea. The predictions were thoroughly validated using known targets described in several public databases. The external validation results are noteworthy, with 16 of 33 (48.5% with p-valuevalue<0.0001) known targets correctly predicted. This level of accuracy in large-scale virtual screening methods is very significant and demonstrates the effectiveness of the Active-IT methodology in predicting the potential biological activities of small organic molecules
Distance-based loss function for deep feature space learning of convolutional neural networks.
No full textConvolutional Neural Networks (CNNs) have been on the forefront of neural network research in recent years. Their breakthrough performance in fields such as image classification has gathered efforts in the development of new CNN-based architectures, but recently more attention has been directed to the study of new loss functions. Softmax loss remains the most popular loss function due mainly to its efficiency in class separation, but the function is unsatisfactory in terms of intra-class compactness. While some studies have addressed this problem, most solutions attempt to refine softmax loss or combine it with other approaches. We present a novel loss function based on distance matrices (LDMAT), softmax independent, that maximizes interclass distance and minimizes intraclass distance. The loss function operates directly on deep features, allowing their use on arbitrary classifiers. LDMAT minimizes the distance between two distance matrices, one constructed with the model’s deep features and the other calculated from the labels. The use of a distance matrix in the loss function allows a two-dimensional representation of features and imposes a fixed distance between classes, while improving intra-class compactness. A regularization method applied to the distance matrix of labels is also presented, that allows a degree of relaxation of the solution and leads to a better spreading of features in the separation space. Efficient feature extraction was observed on datasets such as MNIST, CIFAR10 and CIFAR100
Reimagining beauty : digital consumption practices in a disrupted world.
No full textObjective: the COVID-19 pandemic profoundly disrupted societal norms, reshaping daily routines and consumption practices by blurring the boundaries between personal and public spaces. This study examines how beauty consumption adapted to these disruptions, focusing on the role of digital platforms in fostering self-expression, self-care, and social interaction. Methods: using practice theory as a framework, we employed netnography, in-depth interviews, and archival analysis to explore the interplay between digital tools, self-presentation, and consumer behavior during the pandemic. Results: our findings highlight three key triggers — perception of free time, domestic social exhibition, and insecurity with new routines — that drove the adaptation of beauty practices. Consumers prioritized mental health and self-presentation in digital spaces, embracing new at-home routines facilitated by tools like social media tutorials and virtual try-on technologies. Social media influencers encouraged experimentation, while brands adapted their strategies to promote DIY solutions and align products with emerging values around self-care and virtual presence. Conclusions: this study extends the literature on consumption disruption, offering a framework to understand the co- evolution of consumer practices and market adaptations in digitally mediated contexts
A new methodology proposed to study the evolution of fatigue damage in metallic alloys.
No full textThe aim of this work was to develop and demonstrate the efficiency of an accessible and simple methodology, adapted from small punch fatigue (SPF) concepts, to study the evolution of the fatigue damage in metallic alloys. This demonstration was carried out using a 10 mm thick hot rolled sheet of a lean duplex stainless steel (UNS S32304). The methodology proposed consisted of the design and construction of a SPF device that was adapted to a traditional mechanical testing machine for carrying out fatigue tests in small discs of 10 mm of diameter and 1 mm thickness. Microstructural analyses were performed by Scanning Electron Microscopy (SEM) before and after the fatigue tests loading with predefined interruptions to monitor the fatigue degradation evolution until it was considered the complete failure of the specimen, when the dominant cracks exceeded 1 mm length. In addition, samples of this steel, before and after being subjected to cyclic fatigue loading, were analyzed by Transmission Electron Microscopy (TEM). The methodology proved to be efficient, allowing to identify and monitor, from the initial stages, the events of cyclic plastic deformation that occurred on the surface of the test specimens. Furthermore, it was also possible to identify the initial stages of nucleation and crack growth as well as their relationships with the microstructural aspects of the steel and its thermal history
Social dilemmas, network reciprocity, and small-world property.
No full textWe revisit two evolutionary game theory models, namely the Prisoner and the Snowdrift dilem- mas, on top of small-world networks. These dynamics on networked populations (individuals occupying nodes of a graph) are mainly concerned with the competition between cooperating or defecting by allowing some process of revision of strategies. Cooperators avoid defectors by forming clusters in a process known as network reciprocity. This defense strategy is based on the fact that any individual interacts only with its nearest neighbors. The minimum cluster, in turn, is formed by a set of three completely connected nodes, and the bulk of these triplets is associated with the transitivity property of a network. We show that the transitivity increases eventually, assuming a constant behavior when observed as a function of the number of contacts an individual has. We investigate the influence of the network reciprocity on that transitivity-increasing regime on promoting cooperative behavior. The dynamics of small-world networks are compared with those of random regular and annealed networks, the latter typically studied as the well-mixed approach. The Snowdrift Game converges to an annealed scenario as randomness and coordination numbers increase. In contrast, the Prisoner’s Dilemma becomes more severe against the cooperative behavior under an increasing network reciprocity regime
Sistema de gerenciamento de controle de riscos (RCMS) para avaliação da gestão e governança de estruturas para disposição de rejeitos.
No full textPrograma de Pós-Graduação em Geotecnia. Núcleo de Geotecnia, Escola de Minas, Universidade Federal de Ouro Preto.Esta pesquisa resultou no desenvolvimento de uma ferramenta inovadora para avaliar a efetividade dos controles de riscos na gestão e governança de estruturas de disposição de rejeitos. A ferramenta demonstra a viabilidade de utilizar os requisitos do Padrão Global da Indústria para Gestão de Rejeitos (GISTM) para avaliar o desempenho dessas estruturas, com foco nos controles aplicáveis à gestão e mitigação de riscos. Além disso, engloba a análise de conformidade aos requisitos do GISTM, utilizando um formulário de avaliação de lacunas e propõe uma estrutura organizacional própria que integra o GISTM às diversas áreas-chave da gestão e governança de rejeitos. Para verificar a aplicabilidade da metodologia, foi construído um conjunto de dados de 35 estruturas de disposição de rejeitos de 7 empresas em 5 países. Essa amostragem demonstra boa representatividade e confiabilidade dos resultados da pesquisa. A metodologia para avaliação de desempenho de estruturas de rejeito foi consolidada em um SISTEMA DE GESTÃO DE CONTROLE DE RISCOS denominado RCMS, e oferece dois benefícios principais. O primeiro é facilitar a parametrização dos requisitos do GISTM, minimizando interpretações subjetivas e introduzindo maior consistência na avaliação. O segundo é a introdução de uma avaliação semiquantitativa e sistemática do desempenho da gestão e governança das estruturas de disposição de rejeitos, proporcionando uma visão clara e acionável dos riscos envolvidos. A metodologia utiliza a Análise de Componentes Principais (PCA) para estabelecer índices que estimam os níveis de maturidade dos controles, que, por sua vez, demonstram a influência na consequência e a probabilidade de falha de uma estrutura de disposição de rejeitos, fornecendo um bom indicador para a gestão de riscos. O sistema auxilia na identificação de oportunidades de melhoria para gestão e governança de rejeitos, além de apoiar a tomada de decisões para definir indicadores relacionados aos controles e mitigação do risco de falha. Em resumo, a pesquisa apresenta uma ferramenta robusta e inovadora para avaliar a efetividade dos controles de riscos em estruturas de disposição de rejeitos, contribuindo significativamente para a segurança e o gerenciamento sustentável dessas estruturas.This research resulted in the development of an innovative tool to evaluate the effectiveness of risk controls in the management and governance of tailings storage facilities. The tool demonstrates the feasibility of using the requirements of the Global Industry Standard on Tailings Management (GISTM) to assess the performance of these facilities, focusing on applicable controls for risk management and mitigation. Additionally, it encompasses the analysis of compliance with GISTM requirements using a gap assessment form and proposes a unique organizational framework that integrates GISTM into various key areas of tailings management and governance. To verify the applicability of the methodology, a dataset of 35 tailings storage facilities from 7 companies in 5 countries. This sampling demonstrates good representativeness and reliability of the research results. The methodology for evaluating the performance of tailings facilities was consolidated into a RISK CONTROL MANAGEMENT SYSTEM called RCMS, offering two main benefits. The first is facilitating the parameterization of GISTM requirements, minimizing subjective interpretations, and introducing greater consistency in the assessment. The second is introducing a semiquantitative and systematic evaluation of the performance of tailings storage facilities management and governance, providing a clear and actionable view of the risks involved. The methodology uses Principal Component Analysis (PCA) to establish indices that estimate the maturity levels of controls, which, in turn, demonstrate the influence on the consequence and probability of failure of a tailings storage facility, providing a good indicator for risk management. The system assists in identifying improvement opportunities for tailings management and governance, as well as supporting decision-making to define indicators related to controls and the mitigation of failure risk. In summary, the research presents a robust and innovative tool to evaluate the effectiveness of risk controls in tailings storage facilities, significantly contributing to the safety and sustainable management of these facilities
Razones de adherencia a la actividad física entre estudiantes de secundaria.
No full textO presente estudo verificou os motivos que levam jovens estudantes a aderirem à prática de atividade física. A amostra foi constituída por 489 escolares do 3° ano do ensino médio de Minas Gerais (179 do sexo masculino e 310 do sexo feminino), com idade entre os 16 e 19 anos. Os dados foram obtidos através de questões sociodemográficas e do uso dos questionários IPAQ e IMPRAF-54. Para a análise de dados foi utilizado o software estatístico SPSS 20, com estatística descritiva, comparativa (Teste T-student, Anova com Bonferroni) e correlacional (Pearson e Spearman). Apenas 47.6% da amostra praticam atividade física, sendo o futebol mais praticado pelos rapazes (34.7%) e a musculação pelas moças (8.2%). As dimensões motivacionais mais pontuadas para a prática de atividade física foram a saúde e o prazer, e a menos pontuada foi a competitividade. As comparações em função do sexo e idade apresentaram diferenças significativas na motivação e no nível de atividade física. Também foram encontradas correlações significativas entre os dois questionários, sendo que a dimensão prazer apresentou maior correlação com os dias totais de atividades. Conclui-se que os principais fatores motivacionais para a prática são advindos do interesse à saúde e ao prazer.The present study verified the reasons that lead young students to adhere to the practice of physical activity. The sample consisted of 489 students from the 3rd year of secondary education in Minas Gerais (179 males and 310 females), aged between 16 and 19. Data were obtained through sociodemographic and use of the IPAQ and IMPRAF-54 questionnaires. Statistical software SPSS 20 was used for data analysis, with descriptive, comparative (T student, Anova with Bonferroni) and correlational (Pearson and Spearman) statistics. Only 47.6% of the subjects practice physical activity, with soccer being more practiced by boys (34.7%) and bodybuilding by girls (8.2%). The most scored motivational dimensions for the practice of physical activity were health and pleasure, and the less scored was competitiveness. Comparisons regarding sex and age showed significant differences in motivation and level of physical activity. Significant correlations were also found between the two questionnaires, and pleasure dimension showed higher correlation with the total days of activities. It concludes that the main motivational factors for the practice are of interest for health and pleasure