Análise da influência do índice de risco-país nos retornos do Ibovespa

O objetivo do presente trabalho é avaliar a possível relação entre as variações do risco-país Brasil e os retornos do Ibovespa para o período entre janeiro de 2003 a dezembro de 2021. A metodologia adotada compreende análise de correlação linear e regressão multivariada. Os dados analisado compreendem os retornos mensais do Ibovespa - variável dependente - e as variações mensais do índice de risco-país Brasil. Foram incluídas variáveis macroeconômicas que, segundo a literatura, possuem capacidade de influenciar os retornos do Ibovespa. São elas: a taxa básica de juros, a taxa de câmbio, o índice de inflação e o índice de atividade econômica do Banco Central. Os dados referente ao Ibovespa foram obtidos através do site da bolsa de valores de São Paulo (B3). Para o risco-país, os dados foram coletados no site do Ipeadata. As demais variáveis foram extraídas diretamente no site do Banco Central. Para os cálculos de correlação e regressão, foi utilizado o software Excel 2007. Os resultados encontrados sugerem relação entre as variações do risco-país e os retornos do Ibovespa no período analisado. Além da influência sugerida, foi verificado que entre as variáveis independentes, o risco-país foi a variável com maior coeficiente beta (β) encontrado na regressão multivariada. Indicando que a cada aumento de 1% na variação do risco-país, podemos esperar uma queda média de - 7,32% nos retornos do Ibovespa.The present study aims to evaluate the possible relationship between the variations of Brazil’s country risk and returns in the Brazilian stock exchange indexes(Ibovespa) from January 2003 to December 2021. The methodologies used in the study were the linear correlation analysis and the multivariate regression. The data in the analysis comprehend monthly returns in the Brazilian stock exchange (Ibovespa) indexes - dependent variable - and monthly variations of Brazil’s country risk index. Macroeconomic variables were included, as according to literature, can influence the returns from Brazilian stock exchange (Ibovespa). Such as: basic interest rate, exchange rate, inflation rate and the economic activity index from the Brazilian Central Bank. The stock exchange (Ibovespa) data was obtained through their own website (B3). For the Brazil’s country risk, data was collected from the Ipeadata website. The other variables were collected directly from the Brazilian Central Bank website. To calculate the linear correlation and multivariate regression, was used the software Microsoft Excel 2007. The results found suggest a relationship between Brazil’s country risk variations and the stock exchange (Ibovespa) returns in the period studied. Be sides the suggested influence, it was also verified that among the independent variables, Brazil’s country risk was the variable with the highest beta coefficient (β) found in the multivariate regression, indicating that for each 1% increase in the variation of Brazil’s country risk, we can expect an average drop of - 7.32% in stock exchange (Ibovespa) returns

A Preference-guided Multiobjective Evolutionary Algorithm based on Decomposition

Multiobjective evolutionary algorithms based on decomposition (MOEA/Ds) represent a class of widely employed problem solvers for multicriteria optimization problems. In this work we investigate the adaptation of these methods for incorporating preference information prior to the optimization, so that the search process can be biased towards a Pareto-optimal region that better satisfies the aspirations of a decision-making entity. The incorporation of the Preference-based Adaptive Region-of-interest (PAR) framework into the MOEA/D requires only the modification of the reference points used within the scalarization function, which in principle allows a straightforward use in more sophisticated versions of the base algorithm. Experimental results using the UF benchmark set suggest gains in diversity within the region of interest, without significant losses in convergence

Estudo Dos Mecanismos De Funcionamento Do Algoritmo De Evolução Diferencial

This work presents theoretical considerations and experimental studies on the working mechanisms of the differential evolution (DE) algorithm for nonlinear optimization. A constant relationship between the covariance matrix of the population at a given iteration of the algorithm, and the corresponding covariance matrix of the probability distribution for the differential mutation operator, represented by the set of all possible mutation vectors, is obtained. This relationship is then employed for analyzing the adaptive behavior of the differential evolution algorithm

Metagenomic Approaches for Investigating the Role of the Microbiome in Gut Health and Inflammatory Diseases

The human gut microbiota makes fundamental contributions to host metabolism and immune system. Therefore, perturbations in its composition, a process known as dysbiosis, have an important role in the development of several chronicle diseases, mainly intestinal inflammatory disorders. Culture-independent molecular methods are allowing scientific community to uncover substantive findings, thus giving a more detailed description of the human intestinal microbiota. This chapter presents a review on current metagenomic approaches, based on next-generation sequencing technologies, for investigating bacterial taxonomic classification and predictive function associated with the human gut in health and disease. In this context, we describe recent studies that have been trying to elucidate important alterations in microbiome composition across individuals according to delivery mode, aging, diet and medication that might be linked to susceptibility to immune-mediated diseases. A description of the main bacterial taxa and genes acting in dysbiosis during inflammation, focusing on chronic inflammatory bowel diseases and colorectal cancer, is also explored in this chapter

Preference-guided evolutionary algorithms for optimization with many objectives

Exportado OPUSMade available in DSpace on 2019-08-10T03:20:57Z (GMT). No. of bitstreams: 1 fillipe___dissertation.pdf: 2926085 bytes, checksum: f7a6fbbd8e9115a94f4fe756f04e92bb (MD5) Previous issue date: 4Algoritmos evolutivos tornaram-se muito famosos na resolução de problemas multiobjetivos nas duas últimas décadas. Suas aplicações consistiam praticamente na aproximação de toda a fronteira Pareto-ótima de modo que um Tomador de Decisões pudesse escolher a sua solução preferida depois. Contudo, essa filosofia a posteriori não é muito apropriada para problemas com muitos objetivos, sobretudo devido ao número de soluções necessárias para aproximar a fronteira normalmente cresce exponencialmente, e o processo de decisão pode tornar-se extremamente complicado. Portanto, o presente trabalho propõe a inclusão de preferências durante a etapa de otimização de maneira que, ao invés de o foco estar em toda a fronteira eficiente, uma região menor é considerada, e o contratempo de escolher dentre uma miríade de soluções é amenizado. Dois métodos evolutivos diferentes - um adotando o conhecido non-dominated sorting com Pareto-dominância e outro baseado em indicadores - são considerados, bem como suas adaptações que adotam preferências. Aliado a eles, um novo método é também proposto aqui. Os algoritmos são comparados em um banco de problemas de teste com muitos objetivos, e a qualidade de suas populações finais é avaliada segundo indicadores de convergência e sua habilidade de aproximar a solução preferida do decisor. Os resultados mostram que a inclusão de preferências gera melhorias significativas nos algoritmos, indicando que este método deve receber mais atenção neste campo.Evolutionary Algorithms became very famous in solving multi-objective problems in the last two decades. They were mainly used to approximate the whole extension of the efficient front so a decision maker could choose a preferred solution later. However, this a posteriori way of thinking is not well suited for problems with many objectives, mainly because the number of solutions to approximate the whole front usually increases exponentially, and the decision process can get really hard. Therefore, this work proposes the inclusion of preferences during the optimization process, such that, instead of focusing on the whole Pareto front, a smaller region is considered, so the problem of choosing among many alternatives is alleviated. Two different evolutionary methods - one with the usual non-dominated sorting with Pareto-dominance and another based on indicators - are considered together with their counterparts that take preferences into account. Along with them, a new approach is also proposed here. These algorithms are compared in a benchmark of problems with many objectives, and their outcomes are measured according to convergence and the ability to find the most preferred solutions of the decision maker. The results show that the inclusion of preferences generates significant improvements in the algorithms, indicating that they should deserve more attention in this field

Whey Protein Isolate-Supplemented Beverage, Fermented by Lactobacillus casei BL23 and Propionibacterium freudenreichii 138, in the Prevention of Mucositis in Mice

Mucositis is a clinically important gastrointestinal inflammatory infirmity, generated by antineoplastic drugs cytotoxic effects. The inflammatory process caused by this disease frequently leads to derangements in the alimentary tract and great malaise for the patient. Novel strategies are necessary for its prevention or treatment, as currently available treatments of mucositis have several limitations in relieving its symptoms. In this context, several research groups have investigated the use of probiotic bacteria, and in particular dairy bacterial strains. Compelling evidences reveal that milk fermented by certain probiotic bacteria has the capacity to ameliorate intestinal inflammatory disorders. In addition, innovative probiotic delivery strategies, based on probiotics incorporation into protective matrices, such as whey proteins, were able to increase the therapeutic effect of probiotic strains by providing extra protection for bacteria against environmental stresses. Therefore, in this study, we evaluated the role of the whey protein isolate (WPI), when added to skim milk fermented by Lactobacillus casei BL23 (L. casei BL23) or by Propionibacterium freudenreichii CIRM-BIA138 (P. freudenreichii 138), as a protective matrix against in vitro stress challenges. In addition, we investigated the therapeutic effect of these fermented beverages in a murine model of mucositis induced by 5-Fluorouracil (5-FU). Our results demonstrated that milk supplementation with 30% (w/v) of WPI increases the survival rate of both strains when challenged with acid, bile salts, high temperature and cold storage stresses, compared to fermented skim milk without the addition of WPI. Moreover, treatment with the probiotic beverages prevented weight loss and intestinal damages in mice receiving 5-FU. We conclude that the presence of WPI maximizes the anti-inflammatory effects of L. casei BL23, but not for P. freudenreichii 138, suggesting that whey protein enhancement of probiotic activity might be strain-dependent

Fermented milks, using Lactobacillus casei or Propionibacterium freudenreichii, prevent mucositis, a side effect of chemotherapy, in mice

Mucositis, a common and often debilitating side effect of cancer chemotherapy, is a clinically important gastrointestinal inflammatory disease. It consists in a painful inflammation and ulceration of the mucosa lining the digestive tract, which may compromise proper nutrition of the patient, as well as termination of the treatment. It thus increases mortality and morbidity and contributes to rising health care costs. Its treatment is mainly supportive and often fails to relieve symptoms. Several studies indicate a role of the microbiota and suggest a healing effect of probiotic ingestion. Probiotic bacteria may maintain homeostasis and reduce side effects of chemotherapy toxicity. A major limit to probiotic bacteria anti-inflammatory effect is their susceptibility to digestive stresses and several studies indicate the key protective role of food matrices in increasing probiotics’ effect via the protection of bacteria against digestive constraints. In this study, we investigated the role of fermented milk, using Lactobacillus casei or Propionibacterium freudenreichii as probiotic starter, and of its fortification via addition of whey proteins.Matériels et Méthodes/Materials and methodsWe evaluated the role of whey protein isolate (WPI), when added to skim milk fermented by L. casei BL23 or by P. freudenreichii 138, as a protective matrix against in vitro stress challenges. In addition, we investigated in vivo the therapeutic effect of these fermented beverages in a murine model of mucositis induced by 5-Fluorouracil (5-FU). The monitored outcomes included weight loss, ileum histopathological score, villus height, crypt depth and number of mucus-producing goblet cells.Résultats principaux/Main ResultsThis study demonstrated that milk supplementation with 30% (w/v) of WPI increases the survival rate of both strains when challenged with acid, bile salts, high temperature and cold storage stresses, compared to fermented skim milk without the addition of WPI. Moreover, treatment with the probiotic beverages prevented weight loss and intestinal damages in mice receiving 5-FU. All symptoms of mucositis were drastically reduced by the consumption of developed probiotic fermented milks.ConclusionThis study evidenced the protective effect of selected strains of both lactic and propionic acid bacteria, in the context of induced mucositis. It confirmed that selected strains might be used bot as starter and probiotic. It opens new avenues for the development of fermented functional foods for target populations

Fermented milks, using Lactobacillus casei or Propionibacterium freudenreichii, prevent mucositis, a side effect of chemotherapy, in mice

Mucositis, a common and often debilitating side effect of cancer chemotherapy, is a clinically important gastrointestinal inflammatory disease. It consists in a painful inflammation and ulceration of the mucosa lining the digestive tract, which may compromise proper nutrition of the patient, as well as termination of the treatment. It thus increases mortality and morbidity and contributes to rising health care costs. Its treatment is mainly supportive and often fails to relieve symptoms. Several studies indicate a role of the microbiota and suggest a healing effect of probiotic ingestion. Probiotic bacteria may maintain homeostasis and reduce side effects of chemotherapy toxicity. A major limit to probiotic bacteria anti-inflammatory effect is their susceptibility to digestive stresses and several studies indicate the key protective role of food matrices in increasing probiotics’ effect via the protection of bacteria against digestive constraints. In this study, we investigated the role of fermented milk, using Lactobacillus casei or Propionibacterium freudenreichii as probiotic starter, and of its fortification via addition of whey proteins.Matériels et Méthodes/Materials and methodsWe evaluated the role of whey protein isolate (WPI), when added to skim milk fermented by L. casei BL23 or by P. freudenreichii 138, as a protective matrix against in vitro stress challenges. In addition, we investigated in vivo the therapeutic effect of these fermented beverages in a murine model of mucositis induced by 5-Fluorouracil (5-FU). The monitored outcomes included weight loss, ileum histopathological score, villus height, crypt depth and number of mucus-producing goblet cells.Résultats principaux/Main ResultsThis study demonstrated that milk supplementation with 30% (w/v) of WPI increases the survival rate of both strains when challenged with acid, bile salts, high temperature and cold storage stresses, compared to fermented skim milk without the addition of WPI. Moreover, treatment with the probiotic beverages prevented weight loss and intestinal damages in mice receiving 5-FU. All symptoms of mucositis were drastically reduced by the consumption of developed probiotic fermented milks.ConclusionThis study evidenced the protective effect of selected strains of both lactic and propionic acid bacteria, in the context of induced mucositis. It confirmed that selected strains might be used bot as starter and probiotic. It opens new avenues for the development of fermented functional foods for target populations

Fermented milks, using Lactobacillus casei or Propionibacterium freudenreichii, prevent mucositis, a side effect of chemotherapy, in mice

Mucositis, a common and often debilitating side effect of cancer chemotherapy, is a clinically important gastrointestinal inflammatory disease. It consists in a painful inflammation and ulceration of the mucosa lining the digestive tract, which may compromise proper nutrition of the patient, as well as termination of the treatment. It thus increases mortality and morbidity and contributes to rising health care costs. Its treatment is mainly supportive and often fails to relieve symptoms. Several studies indicate a role of the microbiota and suggest a healing effect of probiotic ingestion. Probiotic bacteria may maintain homeostasis and reduce side effects of chemotherapy toxicity. A major limit to probiotic bacteria anti-inflammatory effect is their susceptibility to digestive stresses and several studies indicate the key protective role of food matrices in increasing probiotics’ effect via the protection of bacteria against digestive constraints. In this study, we investigated the role of fermented milk, using Lactobacillus casei or Propionibacterium freudenreichii as probiotic starter, and of its fortification via addition of whey proteins.Matériels et Méthodes/Materials and methodsWe evaluated the role of whey protein isolate (WPI), when added to skim milk fermented by L. casei BL23 or by P. freudenreichii 138, as a protective matrix against in vitro stress challenges. In addition, we investigated in vivo the therapeutic effect of these fermented beverages in a murine model of mucositis induced by 5-Fluorouracil (5-FU). The monitored outcomes included weight loss, ileum histopathological score, villus height, crypt depth and number of mucus-producing goblet cells.Résultats principaux/Main ResultsThis study demonstrated that milk supplementation with 30% (w/v) of WPI increases the survival rate of both strains when challenged with acid, bile salts, high temperature and cold storage stresses, compared to fermented skim milk without the addition of WPI. Moreover, treatment with the probiotic beverages prevented weight loss and intestinal damages in mice receiving 5-FU. All symptoms of mucositis were drastically reduced by the consumption of developed probiotic fermented milks.ConclusionThis study evidenced the protective effect of selected strains of both lactic and propionic acid bacteria, in the context of induced mucositis. It confirmed that selected strains might be used bot as starter and probiotic. It opens new avenues for the development of fermented functional foods for target populations