Voltage collapse in power systems: Dynamical studies from a static formulation

This paper addresses the problem of voltage collapse in power systems. More precisely, we exhibit a voltage collapse in a power system with two buses. This study is carried out with the help of two approaches. The first is a dynamical approach where a saddle-node bifurcation is analyzed and the second is an algebraic approach. Both approaches deal with the static behavior of the power system, but some dynamic aspects may be observed. An equivalence between the algebraic and dynamical approaches is obtained. The need to use both models comes from the fact that they are usually exploited in the literature, but a deep theoretical justification is still pending. Such a justification is meant in this work

Mental health, quality of life and optimism during the covid-19 pandemic: a comparison between Brazil and Portugal

Purpose Although there have been numerous studies investigating the mental health of individuals during the pandemic, a comparison between countries is still scarce in the literature. To explore this gap, the present study aimed to compare the mental health (i.e., anxiety and depression), quality of life (QoL), and optimism/pessimism among individuals from Brazil and Portugal during the COVID-19 pandemic and the associated factors. Method A cross-sectional population-based study was conducted during the COVID-19 pandemic in Brazil and Portugal. Data collection was carried out between May and June 2020, using an online form which was sent through social networks. A total of 2069 participants (1156 from Brazil and 913 from Portugal) were included. Depressive symptoms (PHQ-9), Anxiety (GAD-7), optimism/pessimism (Revised Life Orientation Test – LOT), QoL (WHOQOL-Bref), and sociodemographic, health, and social distancing variables were assessed. Data was analyzed using univariate and multivariate models. Results There were remarkable diferences between Brazil and Portugal in all outcomes during the COVID-19 pandemic, including higher levels of depressive symptoms, anxiety, and optimism for the Brazilian individuals and higher levels of QoL and pessimism for the Portuguese individuals. The following factors were associated with the mental health and QoL in both Brazilian and Portuguese populations: gender, age, being a healthcare professional, and days in social distancing. Conclusion Despite the fact that Brazilians were more optimistic during the COVID-19 pandemic, they had lower levels of mental health and QoL as compared to the Portuguese individuals.info:eu-repo/semantics/publishedVersio

Analise in vitro da modelagem de canais radiculares apos instrumentação endodontica com limas tipo K, Profile.04 e Quantec 2000

Orientador : Caio Cezar Randi FerrazDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaMestrad

Analise in vitro da microinfiltração coronaria em dentes obturados com tres diferentes tecnicas, utilizando no topo da obturação adesivo dentinario e resina composta

Orientador : Luiz ValdrighiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O presente trabalho teve por objetivo avaliar in vitro a capacidade de selamento de três diferentes técnicas de obturação de canal radicular com e sem barreira de proteção. Foram utilizados 144 canais de raízes mesiais de molares inferiores humanos, extraídos com raízes completamente formadas, armazenados em solução de formol a 10%. Os dentes foram separados aleatoriamente em três grupos experimentais contendo 48 canais obturados com três diferentes técnicas de obturação. Os grupos foram divididos em dois subgrupos A (com proteção) e B (sem proteção) com 24 canais cada. O preparo químico-mecânico dos canais radiculares foi realizado pela técnica mecanizada rotatória Crown-Down de BUCHANAN modificada, com limas GT (Greater Taper) e a matriz apical preparadas com limas manuais tipo K "step-back". Para as obturações foram utilizadas as técnicas da Condensação Lateral de NGUYEN, Compressão Hidráulica de DE DEUS e a Híbrida de TAGGER, tendo sido empregado, para todos os grupos o cimento AH plus. Os dentes foram impermeabilizados com esmalte para unha, imersos em tinta Nanquim por um período de 7 dias e submetidos ao vácuo por 30 minutos. Para a observação dos níveis de infiltração, as amostras foram desmineralizadas, desidratadas, diafanizadas e examinadas em lupa esteroscópio. Os resultados foram submetidos à análise de variância e teste Tukey para comparações entre as médias. Observou-se que não houve diferença estatística significante entre as técnicas de obturação, e evidenciou-se que os procedimentos complementares aplicados sobre o topo da obturação, assoalho e paredes laterais da câmara pulpar contribuiu significativamente para a prevenção da microinfiltração coronáriaAbstract: The purpose of this in vitro study was to compare the ability of three different root canal filling techniques to prevent coronal microleakage. Seventy two extracted human mandibular posterior teeth (144 root canais) were prepared, to a size 35 (MAF). The Crown-Down and Step-Back techniques were associated and GT rotary files were used. Three groups of 48 root canais each and divided in two subgroups with 24 root canais each were randomly placed. The canais were filled with gutta-percha points and AH plus sealer using by Hybrid Technique, Hydraulic Compression and Lateral Condensation techniques. After the sealer had set, the whole roots surfaces were coated with two layers nail vanish. The specimens were placed in 60mm Hg vacuum for thirty minutes and then immersed in India ink for five days. These teeth were decalcified, dehydrated and cleared to allow direct measurement of linear dye penetration under stereomicroscope. The analysis of variance and Tukey test were used and no difference statistically significant was related to leakage among the groupsDoutoradoEndodontiaDoutor em Clínica Odontológic

A mathematical model on acute promyelocytic leukemia based on ordinary differential equations

A Leucemia Promielocítica Aguda (LPA) é uma condição incomum, potencialmente letal, no qual o tratamento baseado em análise de risco de recaída levou a melhores resultados terapêuticos. Devido à raridade e sobrevida global relativamente alta, ensaios clínicos prospectivos para investigar protocolos alternativos de tratamento são desafiadores. Modelos matemáticos podem oferecer informações úteis neste cenário, otimizando tempo e custos de estudo, aumento as chances de resultados positivos. Foram coletados dados clínicos e laboratoriais dos primeiros 30 dias de tratamento de todos os 39 pacientes diagnosticados com LPA tratados no Hospital das Clínicas de Ribeirão Preto (HCRP) sob o protocolo de tratamento do International Consortium on Acute Leukemia (ICAL). Foi proposto um modelo matemático baseado em Equações Diferenciais Ordinárias (EDOs) que representa a dinâmica dos leucócitos no sangue periférico e os efeitos do protocolo ICAL de tratamento na dinâmica da doença. Observou-se que a coorte do HCRP apresenta características demográficas e desfechos clínicos comparáveis aos publicados em estudos prévios em LPA. Com 41,8 meses de seguimento mediano, sobrevida livre de recaída e sobrevida global em dois anos foram ambos de 78,7%. Para um conjunto adequado de dados laboratoriais, as soluções oferecidas pelo modelo ajustam-se adequadamente. Informações derivadas do modelo podem auxiliar na prática clínica e no desenho de ensaios clínicos, sugerindo protocolos de tratamento e determinando riscos de recaída.Acute Promyelocytic Leukemia (APL) is a rare condition, potentially lethal, in which risk-based therapy led to better outcomes. Due to its rarity and relatively high overall survival rate, prospective randomized trials to investigate alternative treatment schedules are challenging. Mathematical models may provide useful information in this matter. We collected clinical data from 39 patients treated for APL under the International Consortium on Acute Leukemia (ICAL) protocol and laboratory data during induction. We propose a mathematical model based on Ordinary Differential Equations (ODEs) that represents the dynamics of leucocytes in peripheral blood and the effect of ICAL treatment on the disease\'s dynamics. We observed that our cohort presents demographic characteristics and clinical outcomes similar to previous clinical trials on APL. With 41.8 months of follow-up, relapse-free survival and overall survival at two years were both 78.7%. For an adequate set of clinical data, the model solutions show good fit. Pieces of information derived from the model may assist in clinical practice and design of clinical trials, suggesting alternative chemotherapy protocols and determining the risk of relapse

Vivência de mulheres frente ao câncer de mama: revisão da literatura brasileira / The experience of women facing breast cancer: a review of Brazilian scientific literature

O câncer de mama é a neoplasia mais incidente nas mulheres (exceto o câncer de pele não melanoma), justificando-se uma preocupação com seu impacto na vida dessas pacientes. Procedeu-se uma revisão integrativa da literatura nacional, buscando artigos relacionados ao tema na plataforma SciELO, utilizando-se os buscadores “câncer de mama” e “vivência”, sem restrições com relação ao período de publicação ou tipo de artigo, sendo recuperadas onze publicações. Da análise integrativa das publicações, conclui-se que a experiência de cada paciente com seu processo de doença é pessoal; porém, guarda algumas similaridades que devem ser identificadas e corretamente trabalhadas, posto que sentimentos conflitantes podem coexistir. Tais conflitos são evidenciados na identificação de distorções de autoimagem, sexualidade e a incerteza sobre o futuro, em contraposição à coragem para o enfrentamento, ressignificação da vida e a percepção do apoio familiar. Palavras-Chave: Neoplasias da mama; Acontecimentos que mudam a vida; Equipe de assistência ao paciente Breast cancer is the most incident neoplasm in women (except for non-melanoma skin cancer). This fact justifies a concern on how it impacts on the life of the patients. We proceeded an integrative review of the national literature, in SciELO database, under the following keywords: "breast cancer" and " life experience." No restriction regarding the period of publication was imposed. We retrieved eleven articles. From the analysis of the publications, we concluded that the experience of each patient with their disease process is personal, but it does have some similarities that must be identified and correctly worked out since conflicting feelings can coexist. We highlight distortions on self-image, issues regarding sexuality and uncertainties about the future as negative factors. On the other hand, courage facing the future after the disease, life's meaning resignification, and family's support were identified as positive factors. Keywords: Breast neoplasms; Life change events; Patient care tea

Modeling dynamics and alternative treatment strategies in acute promyelocytic leukemia.

Acute Promyelocytic Leukemia (APL) is a rare and potentially lethal condition in which risk-based therapy often leads to better outcomes. Because of its rarity and relatively high overall survival rate, prospective randomized trials to investigate alternative APL treatment schedules are challenging. Mathematical models may provide useful information in this regard. We collected clinical data from 38 patients treated for APL under the International Consortium on Acute Leukemia (ICAL) protocol and laboratory data during induction therapy. We propose a mathematical model that represents the dynamics of leukocytes in peripheral blood and the effect of ICAL treatment on the disease's dynamics. We observe that our cohort presents demographic characteristics and clinical outcomes similar to previous clinical trials on APL. Over a follow-up period of 41.8 months, the relapse-free survival and overall survival at two years are both found to be 78.7%. For two selected patients, the model produces a good fit to the clinical data. Information such as the response to treatment and risk of relapse can be derived from the model, and this may assist in clinical practice and the design of clinical trials